/* vi: set sw=4 ts=4: */ /* * A prototype Bourne shell grammar parser. * Intended to follow the original Thompson and Ritchie * "small and simple is beautiful" philosophy, which * incidentally is a good match to today's BusyBox. * * Copyright (C) 2000,2001 Larry Doolittle * Copyright (C) 2008,2009 Denys Vlasenko * * Credits: * The parser routines proper are all original material, first * written Dec 2000 and Jan 2001 by Larry Doolittle. The * execution engine, the builtins, and much of the underlying * support has been adapted from busybox-0.49pre's lash, which is * Copyright (C) 1999-2004 by Erik Andersen * written by Erik Andersen . That, in turn, * is based in part on ladsh.c, by Michael K. Johnson and Erik W. * Troan, which they placed in the public domain. I don't know * how much of the Johnson/Troan code has survived the repeated * rewrites. * * Other credits: * o_addchr derived from similar w_addchar function in glibc-2.2. * parse_redirect, redirect_opt_num, and big chunks of main * and many builtins derived from contributions by Erik Andersen. * Miscellaneous bugfixes from Matt Kraai. * * There are two big (and related) architecture differences between * this parser and the lash parser. One is that this version is * actually designed from the ground up to understand nearly all * of the Bourne grammar. The second, consequential change is that * the parser and input reader have been turned inside out. Now, * the parser is in control, and asks for input as needed. The old * way had the input reader in control, and it asked for parsing to * take place as needed. The new way makes it much easier to properly * handle the recursion implicit in the various substitutions, especially * across continuation lines. * * POSIX syntax not implemented: * aliases * <(list) and >(list) Process Substitution * Tilde Expansion * * Bash stuff (optionally enabled): * &> and >& redirection of stdout+stderr * Brace Expansion * reserved words: [[ ]] function select * substrings ${var:1:5} * let EXPR [EXPR...] * Each EXPR is an arithmetic expression (ARITHMETIC EVALUATION) * If the last arg evaluates to 0, let returns 1; 0 otherwise. * NB: let `echo 'a=a + 1'` - error (IOW: multi-word expansion is used) * ((EXPR)) * The EXPR is evaluated according to ARITHMETIC EVALUATION. * This is exactly equivalent to let "expression". * * TODOs: * grep for "TODO" and fix (some of them are easy) * special variables (done: PWD) * follow IFS rules more precisely, including update semantics * export builtin should be special, its arguments are assignments * and therefore expansion of them should be "one-word" expansion: * $ export i=`echo 'a b'` # export has one arg: "i=a b" * compare with: * $ ls i=`echo 'a b'` # ls has two args: "i=a" and "b" * ls: cannot access i=a: No such file or directory * ls: cannot access b: No such file or directory * Note1: same applies to local builtin. * Note2: bash 3.2.33(1) does this only if export word itself * is not quoted: * $ export i=`echo 'aaa bbb'`; echo "$i" * aaa bbb * $ "export" i=`echo 'aaa bbb'`; echo "$i" * aaa * * Licensed under the GPL v2 or later, see the file LICENSE in this tarball. */ #include "busybox.h" /* for APPLET_IS_NOFORK/NOEXEC */ #include /* for malloc_trim */ #include /* #include */ #if ENABLE_HUSH_CASE # include #endif #include "shell_common.h" #include "builtin_read.h" #include "builtin_ulimit.h" #include "math.h" #include "match.h" #if ENABLE_HUSH_RANDOM_SUPPORT # include "random.h" #else # define CLEAR_RANDOM_T(rnd) ((void)0) #endif #ifndef PIPE_BUF # define PIPE_BUF 4096 /* amount of buffering in a pipe */ #endif /* Build knobs */ #define LEAK_HUNTING 0 #define BUILD_AS_NOMMU 0 /* Enable/disable sanity checks. Ok to enable in production, * only adds a bit of bloat. Set to >1 to get non-production level verbosity. * Keeping 1 for now even in released versions. */ #define HUSH_DEBUG 1 /* Slightly bigger (+200 bytes), but faster hush. * So far it only enables a trick with counting SIGCHLDs and forks, * which allows us to do fewer waitpid's. * (we can detect a case where neither forks were done nor SIGCHLDs happened * and therefore waitpid will return the same result as last time) */ #define ENABLE_HUSH_FAST 0 #if BUILD_AS_NOMMU # undef BB_MMU # undef USE_FOR_NOMMU # undef USE_FOR_MMU # define BB_MMU 0 # define USE_FOR_NOMMU(...) __VA_ARGS__ # define USE_FOR_MMU(...) #endif #define SKIP_definitions 1 #include "applet_tables.h" #undef SKIP_definitions #if NUM_APPLETS == 1 /* STANDALONE does not make sense, and won't compile */ # undef CONFIG_FEATURE_SH_STANDALONE # undef ENABLE_FEATURE_SH_STANDALONE # undef IF_FEATURE_SH_STANDALONE # undef IF_NOT_FEATURE_SH_STANDALONE # define ENABLE_FEATURE_SH_STANDALONE 0 # define IF_FEATURE_SH_STANDALONE(...) # define IF_NOT_FEATURE_SH_STANDALONE(...) __VA_ARGS__ #endif #if !ENABLE_HUSH_INTERACTIVE # undef ENABLE_FEATURE_EDITING # define ENABLE_FEATURE_EDITING 0 # undef ENABLE_FEATURE_EDITING_FANCY_PROMPT # define ENABLE_FEATURE_EDITING_FANCY_PROMPT 0 #endif /* Do we support ANY keywords? */ #if ENABLE_HUSH_IF || ENABLE_HUSH_LOOPS || ENABLE_HUSH_CASE # define HAS_KEYWORDS 1 # define IF_HAS_KEYWORDS(...) __VA_ARGS__ # define IF_HAS_NO_KEYWORDS(...) #else # define HAS_KEYWORDS 0 # define IF_HAS_KEYWORDS(...) # define IF_HAS_NO_KEYWORDS(...) __VA_ARGS__ #endif /* If you comment out one of these below, it will be #defined later * to perform debug printfs to stderr: */ #define debug_printf(...) do {} while (0) /* Finer-grained debug switches */ #define debug_printf_parse(...) do {} while (0) #define debug_print_tree(a, b) do {} while (0) #define debug_printf_exec(...) do {} while (0) #define debug_printf_env(...) do {} while (0) #define debug_printf_jobs(...) do {} while (0) #define debug_printf_expand(...) do {} while (0) #define debug_printf_glob(...) do {} while (0) #define debug_printf_list(...) do {} while (0) #define debug_printf_subst(...) do {} while (0) #define debug_printf_clean(...) do {} while (0) #define ERR_PTR ((void*)(long)1) #define JOB_STATUS_FORMAT "[%d] %-22s %.40s\n" #define SPECIAL_VAR_SYMBOL 3 struct variable; static const char hush_version_str[] ALIGN1 = "HUSH_VERSION="BB_VER; /* This supports saving pointers malloced in vfork child, * to be freed in the parent. */ #if !BB_MMU typedef struct nommu_save_t { char **new_env; struct variable *old_vars; char **argv; char **argv_from_re_execing; } nommu_save_t; #endif typedef enum reserved_style { RES_NONE = 0, #if ENABLE_HUSH_IF RES_IF , RES_THEN , RES_ELIF , RES_ELSE , RES_FI , #endif #if ENABLE_HUSH_LOOPS RES_FOR , RES_WHILE , RES_UNTIL , RES_DO , RES_DONE , #endif #if ENABLE_HUSH_LOOPS || ENABLE_HUSH_CASE RES_IN , #endif #if ENABLE_HUSH_CASE RES_CASE , /* three pseudo-keywords support contrived "case" syntax: */ RES_CASE_IN, /* "case ... IN", turns into RES_MATCH when IN is observed */ RES_MATCH , /* "word)" */ RES_CASE_BODY, /* "this command is inside CASE" */ RES_ESAC , #endif RES_XXXX , RES_SNTX } reserved_style; typedef struct o_string { char *data; int length; /* position where data is appended */ int maxlen; /* Protect newly added chars against globbing * (by prepending \ to *, ?, [, \) */ smallint o_escape; smallint o_glob; /* At least some part of the string was inside '' or "", * possibly empty one: word"", wo''rd etc. */ smallint o_quoted; smallint has_empty_slot; smallint o_assignment; /* 0:maybe, 1:yes, 2:no */ } o_string; enum { MAYBE_ASSIGNMENT = 0, DEFINITELY_ASSIGNMENT = 1, NOT_ASSIGNMENT = 2, WORD_IS_KEYWORD = 3, /* not assigment, but next word may be: "if v=xyz cmd;" */ }; /* Used for initialization: o_string foo = NULL_O_STRING; */ #define NULL_O_STRING { NULL } /* I can almost use ordinary FILE*. Is open_memstream() universally * available? Where is it documented? */ typedef struct in_str { const char *p; /* eof_flag=1: last char in ->p is really an EOF */ char eof_flag; /* meaningless if ->p == NULL */ char peek_buf[2]; #if ENABLE_HUSH_INTERACTIVE smallint promptme; smallint promptmode; /* 0: PS1, 1: PS2 */ #endif FILE *file; int (*get) (struct in_str *) FAST_FUNC; int (*peek) (struct in_str *) FAST_FUNC; } in_str; #define i_getch(input) ((input)->get(input)) #define i_peek(input) ((input)->peek(input)) /* The descrip member of this structure is only used to make * debugging output pretty */ static const struct { int mode; signed char default_fd; char descrip[3]; } redir_table[] = { { O_RDONLY, 0, "<" }, { O_CREAT|O_TRUNC|O_WRONLY, 1, ">" }, { O_CREAT|O_APPEND|O_WRONLY, 1, ">>" }, { O_CREAT|O_RDWR, 1, "<>" }, { O_RDONLY, 0, "<<" }, /* Should not be needed. Bogus default_fd helps in debugging */ /* { O_RDONLY, 77, "<<" }, */ }; struct redir_struct { struct redir_struct *next; char *rd_filename; /* filename */ int rd_fd; /* fd to redirect */ /* fd to redirect to, or -3 if rd_fd is to be closed (n>&-) */ int rd_dup; smallint rd_type; /* (enum redir_type) */ /* note: for heredocs, rd_filename contains heredoc delimiter, * and subsequently heredoc itself; and rd_dup is a bitmask: * bit 0: do we need to trim leading tabs? * bit 1: is heredoc quoted (<<'delim' syntax) ? */ }; typedef enum redir_type { REDIRECT_INPUT = 0, REDIRECT_OVERWRITE = 1, REDIRECT_APPEND = 2, REDIRECT_IO = 3, REDIRECT_HEREDOC = 4, REDIRECT_HEREDOC2 = 5, /* REDIRECT_HEREDOC after heredoc is loaded */ REDIRFD_CLOSE = -3, REDIRFD_SYNTAX_ERR = -2, REDIRFD_TO_FILE = -1, /* otherwise, rd_fd is redirected to rd_dup */ HEREDOC_SKIPTABS = 1, HEREDOC_QUOTED = 2, } redir_type; struct command { pid_t pid; /* 0 if exited */ int assignment_cnt; /* how many argv[i] are assignments? */ smallint is_stopped; /* is the command currently running? */ smallint cmd_type; /* CMD_xxx */ #define CMD_NORMAL 0 #define CMD_SUBSHELL 1 /* used for "[[ EXPR ]]" */ #if ENABLE_HUSH_BASH_COMPAT # define CMD_SINGLEWORD_NOGLOB 2 #endif /* used for "export noglob=* glob* a=`echo a b`" */ //#define CMD_SINGLEWORD_NOGLOB_COND 3 // It is hard to implement correctly, it adds significant amounts of tricky code, // and all this is only useful for really obscure export statements // almost nobody would use anyway. #ifdef CMD_SINGLEWORD_NOGLOB_COND // guards the code which implements it, but I have doubts it works // in all cases (especially with mixed globbed/non-globbed arguments) #if ENABLE_HUSH_FUNCTIONS # define CMD_FUNCDEF 3 #endif /* if non-NULL, this "command" is { list }, ( list ), or a compound statement */ struct pipe *group; #if !BB_MMU char *group_as_string; #endif #if ENABLE_HUSH_FUNCTIONS struct function *child_func; /* This field is used to prevent a bug here: * while...do f1() {a;}; f1; f1() {b;}; f1; done * When we execute "f1() {a;}" cmd, we create new function and clear * cmd->group, cmd->group_as_string, cmd->argv[0]. * When we execute "f1() {b;}", we notice that f1 exists, * and that its "parent cmd" struct is still "alive", * we put those fields back into cmd->xxx * (struct function has ->parent_cmd ptr to facilitate that). * When we loop back, we can execute "f1() {a;}" again and set f1 correctly. * Without this trick, loop would execute a;b;b;b;... * instead of correct sequence a;b;a;b;... * When command is freed, it severs the link * (sets ->child_func->parent_cmd to NULL). */ #endif char **argv; /* command name and arguments */ /* argv vector may contain variable references (^Cvar^C, ^C0^C etc) * and on execution these are substituted with their values. * Substitution can make _several_ words out of one argv[n]! * Example: argv[0]=='.^C*^C.' here: echo .$*. * References of the form ^C`cmd arg^C are `cmd arg` substitutions. */ struct redir_struct *redirects; /* I/O redirections */ }; /* Is there anything in this command at all? */ #define IS_NULL_CMD(cmd) \ (!(cmd)->group && !(cmd)->argv && !(cmd)->redirects) struct pipe { struct pipe *next; int num_cmds; /* total number of commands in pipe */ int alive_cmds; /* number of commands running (not exited) */ int stopped_cmds; /* number of commands alive, but stopped */ #if ENABLE_HUSH_JOB int jobid; /* job number */ pid_t pgrp; /* process group ID for the job */ char *cmdtext; /* name of job */ #endif struct command *cmds; /* array of commands in pipe */ smallint followup; /* PIPE_BG, PIPE_SEQ, PIPE_OR, PIPE_AND */ IF_HAS_KEYWORDS(smallint pi_inverted;) /* "! cmd | cmd" */ IF_HAS_KEYWORDS(smallint res_word;) /* needed for if, for, while, until... */ }; typedef enum pipe_style { PIPE_SEQ = 1, PIPE_AND = 2, PIPE_OR = 3, PIPE_BG = 4, } pipe_style; /* Is there anything in this pipe at all? */ #define IS_NULL_PIPE(pi) \ ((pi)->num_cmds == 0 IF_HAS_KEYWORDS( && (pi)->res_word == RES_NONE)) /* This holds pointers to the various results of parsing */ struct parse_context { /* linked list of pipes */ struct pipe *list_head; /* last pipe (being constructed right now) */ struct pipe *pipe; /* last command in pipe (being constructed right now) */ struct command *command; /* last redirect in command->redirects list */ struct redir_struct *pending_redirect; #if !BB_MMU o_string as_string; #endif #if HAS_KEYWORDS smallint ctx_res_w; smallint ctx_inverted; /* "! cmd | cmd" */ #if ENABLE_HUSH_CASE smallint ctx_dsemicolon; /* ";;" seen */ #endif /* bitmask of FLAG_xxx, for figuring out valid reserved words */ int old_flag; /* group we are enclosed in: * example: "if pipe1; pipe2; then pipe3; fi" * when we see "if" or "then", we malloc and copy current context, * and make ->stack point to it. then we parse pipeN. * when closing "then" / fi" / whatever is found, * we move list_head into ->stack->command->group, * copy ->stack into current context, and delete ->stack. * (parsing of { list } and ( list ) doesn't use this method) */ struct parse_context *stack; #endif }; /* On program start, environ points to initial environment. * putenv adds new pointers into it, unsetenv removes them. * Neither of these (de)allocates the strings. * setenv allocates new strings in malloc space and does putenv, * and thus setenv is unusable (leaky) for shell's purposes */ #define setenv(...) setenv_is_leaky_dont_use() struct variable { struct variable *next; char *varstr; /* points to "name=" portion */ #if ENABLE_HUSH_LOCAL unsigned func_nest_level; #endif int max_len; /* if > 0, name is part of initial env; else name is malloced */ smallint flg_export; /* putenv should be done on this var */ smallint flg_read_only; }; enum { BC_BREAK = 1, BC_CONTINUE = 2, }; #if ENABLE_HUSH_FUNCTIONS struct function { struct function *next; char *name; struct command *parent_cmd; struct pipe *body; # if !BB_MMU char *body_as_string; # endif }; #endif /* "Globals" within this file */ /* Sorted roughly by size (smaller offsets == smaller code) */ struct globals { /* interactive_fd != 0 means we are an interactive shell. * If we are, then saved_tty_pgrp can also be != 0, meaning * that controlling tty is available. With saved_tty_pgrp == 0, * job control still works, but terminal signals * (^C, ^Z, ^Y, ^\) won't work at all, and background * process groups can only be created with "cmd &". * With saved_tty_pgrp != 0, hush will use tcsetpgrp() * to give tty to the foreground process group, * and will take it back when the group is stopped (^Z) * or killed (^C). */ #if ENABLE_HUSH_INTERACTIVE /* 'interactive_fd' is a fd# open to ctty, if we have one * _AND_ if we decided to act interactively */ int interactive_fd; const char *PS1; const char *PS2; # define G_interactive_fd (G.interactive_fd) #else # define G_interactive_fd 0 #endif #if ENABLE_FEATURE_EDITING line_input_t *line_input_state; #endif pid_t root_pid; pid_t root_ppid; pid_t last_bg_pid; #if ENABLE_HUSH_RANDOM_SUPPORT random_t random_gen; #endif #if ENABLE_HUSH_JOB int run_list_level; int last_jobid; pid_t saved_tty_pgrp; struct pipe *job_list; # define G_saved_tty_pgrp (G.saved_tty_pgrp) #else # define G_saved_tty_pgrp 0 #endif smallint flag_SIGINT; #if ENABLE_HUSH_LOOPS smallint flag_break_continue; #endif #if ENABLE_HUSH_FUNCTIONS /* 0: outside of a function (or sourced file) * -1: inside of a function, ok to use return builtin * 1: return is invoked, skip all till end of func */ smallint flag_return_in_progress; #endif smallint fake_mode; smallint exiting; /* used to prevent EXIT trap recursion */ /* These four support $?, $#, and $1 */ smalluint last_exitcode; /* are global_argv and global_argv[1..n] malloced? (note: not [0]) */ smalluint global_args_malloced; smalluint inherited_set_is_saved; /* how many non-NULL argv's we have. NB: $# + 1 */ int global_argc; char **global_argv; #if !BB_MMU char *argv0_for_re_execing; #endif #if ENABLE_HUSH_LOOPS unsigned depth_break_continue; unsigned depth_of_loop; #endif const char *ifs; const char *cwd; struct variable *top_var; /* = &G.shell_ver (set in main()) */ struct variable shell_ver; #if ENABLE_HUSH_FUNCTIONS struct function *top_func; # if ENABLE_HUSH_LOCAL struct variable **shadowed_vars_pp; unsigned func_nest_level; # endif #endif /* Signal and trap handling */ #if ENABLE_HUSH_FAST unsigned count_SIGCHLD; unsigned handled_SIGCHLD; smallint we_have_children; #endif /* which signals have non-DFL handler (even with no traps set)? */ unsigned non_DFL_mask; char **traps; /* char *traps[NSIG] */ sigset_t blocked_set; sigset_t inherited_set; #if HUSH_DEBUG unsigned long memleak_value; int debug_indent; #endif char user_input_buf[ENABLE_FEATURE_EDITING ? CONFIG_FEATURE_EDITING_MAX_LEN : 2]; }; #define G (*ptr_to_globals) /* Not #defining name to G.name - this quickly gets unwieldy * (too many defines). Also, I actually prefer to see when a variable * is global, thus "G." prefix is a useful hint */ #define INIT_G() do { \ SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \ } while (0) /* Function prototypes for builtins */ static int builtin_cd(char **argv) FAST_FUNC; static int builtin_echo(char **argv) FAST_FUNC; static int builtin_eval(char **argv) FAST_FUNC; static int builtin_exec(char **argv) FAST_FUNC; static int builtin_exit(char **argv) FAST_FUNC; static int builtin_export(char **argv) FAST_FUNC; #if ENABLE_HUSH_JOB static int builtin_fg_bg(char **argv) FAST_FUNC; static int builtin_jobs(char **argv) FAST_FUNC; #endif #if ENABLE_HUSH_HELP static int builtin_help(char **argv) FAST_FUNC; #endif #if ENABLE_HUSH_LOCAL static int builtin_local(char **argv) FAST_FUNC; #endif #if HUSH_DEBUG static int builtin_memleak(char **argv) FAST_FUNC; #endif #if ENABLE_PRINTF static int builtin_printf(char **argv) FAST_FUNC; #endif static int builtin_pwd(char **argv) FAST_FUNC; static int builtin_read(char **argv) FAST_FUNC; static int builtin_set(char **argv) FAST_FUNC; static int builtin_shift(char **argv) FAST_FUNC; static int builtin_source(char **argv) FAST_FUNC; static int builtin_test(char **argv) FAST_FUNC; static int builtin_trap(char **argv) FAST_FUNC; static int builtin_type(char **argv) FAST_FUNC; static int builtin_true(char **argv) FAST_FUNC; static int builtin_umask(char **argv) FAST_FUNC; static int builtin_unset(char **argv) FAST_FUNC; static int builtin_wait(char **argv) FAST_FUNC; #if ENABLE_HUSH_LOOPS static int builtin_break(char **argv) FAST_FUNC; static int builtin_continue(char **argv) FAST_FUNC; #endif #if ENABLE_HUSH_FUNCTIONS static int builtin_return(char **argv) FAST_FUNC; #endif /* Table of built-in functions. They can be forked or not, depending on * context: within pipes, they fork. As simple commands, they do not. * When used in non-forking context, they can change global variables * in the parent shell process. If forked, of course they cannot. * For example, 'unset foo | whatever' will parse and run, but foo will * still be set at the end. */ struct built_in_command { const char *b_cmd; int (*b_function)(char **argv) FAST_FUNC; #if ENABLE_HUSH_HELP const char *b_descr; # define BLTIN(cmd, func, help) { cmd, func, help } #else # define BLTIN(cmd, func, help) { cmd, func } #endif }; static const struct built_in_command bltins1[] = { BLTIN("." , builtin_source , "Run commands in a file"), BLTIN(":" , builtin_true , NULL), #if ENABLE_HUSH_JOB BLTIN("bg" , builtin_fg_bg , "Resume a job in the background"), #endif #if ENABLE_HUSH_LOOPS BLTIN("break" , builtin_break , "Exit from a loop"), #endif BLTIN("cd" , builtin_cd , "Change directory"), #if ENABLE_HUSH_LOOPS BLTIN("continue" , builtin_continue, "Start new loop iteration"), #endif BLTIN("eval" , builtin_eval , "Construct and run shell command"), BLTIN("exec" , builtin_exec , "Execute command, don't return to shell"), BLTIN("exit" , builtin_exit , "Exit"), BLTIN("export" , builtin_export , "Set environment variables"), #if ENABLE_HUSH_JOB BLTIN("fg" , builtin_fg_bg , "Bring job into the foreground"), #endif #if ENABLE_HUSH_HELP BLTIN("help" , builtin_help , NULL), #endif #if ENABLE_HUSH_JOB BLTIN("jobs" , builtin_jobs , "List jobs"), #endif #if ENABLE_HUSH_LOCAL BLTIN("local" , builtin_local , "Set local variables"), #endif #if HUSH_DEBUG BLTIN("memleak" , builtin_memleak , NULL), #endif BLTIN("read" , builtin_read , "Input into variable"), #if ENABLE_HUSH_FUNCTIONS BLTIN("return" , builtin_return , "Return from a function"), #endif BLTIN("set" , builtin_set , "Set/unset positional parameters"), BLTIN("shift" , builtin_shift , "Shift positional parameters"), BLTIN("trap" , builtin_trap , "Trap signals"), BLTIN("type" , builtin_type , "Write a description of command type"), BLTIN("ulimit" , shell_builtin_ulimit , "Control resource limits"), BLTIN("umask" , builtin_umask , "Set file creation mask"), BLTIN("unset" , builtin_unset , "Unset variables"), BLTIN("wait" , builtin_wait , "Wait for process"), }; /* For now, echo and test are unconditionally enabled. * Maybe make it configurable? */ static const struct built_in_command bltins2[] = { BLTIN("[" , builtin_test , NULL), BLTIN("echo" , builtin_echo , NULL), #if ENABLE_PRINTF BLTIN("printf" , builtin_printf , NULL), #endif BLTIN("pwd" , builtin_pwd , NULL), BLTIN("test" , builtin_test , NULL), }; /* Debug printouts. */ #if HUSH_DEBUG /* prevent disasters with G.debug_indent < 0 */ # define indent() fprintf(stderr, "%*s", (G.debug_indent * 2) & 0xff, "") # define debug_enter() (G.debug_indent++) # define debug_leave() (G.debug_indent--) #else # define indent() ((void)0) # define debug_enter() ((void)0) # define debug_leave() ((void)0) #endif #ifndef debug_printf # define debug_printf(...) (indent(), fprintf(stderr, __VA_ARGS__)) #endif #ifndef debug_printf_parse # define debug_printf_parse(...) (indent(), fprintf(stderr, __VA_ARGS__)) #endif #ifndef debug_printf_exec #define debug_printf_exec(...) (indent(), fprintf(stderr, __VA_ARGS__)) #endif #ifndef debug_printf_env # define debug_printf_env(...) (indent(), fprintf(stderr, __VA_ARGS__)) #endif #ifndef debug_printf_jobs # define debug_printf_jobs(...) (indent(), fprintf(stderr, __VA_ARGS__)) # define DEBUG_JOBS 1 #else # define DEBUG_JOBS 0 #endif #ifndef debug_printf_expand # define debug_printf_expand(...) (indent(), fprintf(stderr, __VA_ARGS__)) # define DEBUG_EXPAND 1 #else # define DEBUG_EXPAND 0 #endif #ifndef debug_printf_glob # define debug_printf_glob(...) (indent(), fprintf(stderr, __VA_ARGS__)) # define DEBUG_GLOB 1 #else # define DEBUG_GLOB 0 #endif #ifndef debug_printf_list # define debug_printf_list(...) (indent(), fprintf(stderr, __VA_ARGS__)) #endif #ifndef debug_printf_subst # define debug_printf_subst(...) (indent(), fprintf(stderr, __VA_ARGS__)) #endif #ifndef debug_printf_clean # define debug_printf_clean(...) (indent(), fprintf(stderr, __VA_ARGS__)) # define DEBUG_CLEAN 1 #else # define DEBUG_CLEAN 0 #endif #if DEBUG_EXPAND static void debug_print_strings(const char *prefix, char **vv) { indent(); fprintf(stderr, "%s:\n", prefix); while (*vv) fprintf(stderr, " '%s'\n", *vv++); } #else # define debug_print_strings(prefix, vv) ((void)0) #endif /* Leak hunting. Use hush_leaktool.sh for post-processing. */ #if LEAK_HUNTING static void *xxmalloc(int lineno, size_t size) { void *ptr = xmalloc((size + 0xff) & ~0xff); fdprintf(2, "line %d: malloc %p\n", lineno, ptr); return ptr; } static void *xxrealloc(int lineno, void *ptr, size_t size) { ptr = xrealloc(ptr, (size + 0xff) & ~0xff); fdprintf(2, "line %d: realloc %p\n", lineno, ptr); return ptr; } static char *xxstrdup(int lineno, const char *str) { char *ptr = xstrdup(str); fdprintf(2, "line %d: strdup %p\n", lineno, ptr); return ptr; } static void xxfree(void *ptr) { fdprintf(2, "free %p\n", ptr); free(ptr); } #define xmalloc(s) xxmalloc(__LINE__, s) #define xrealloc(p, s) xxrealloc(__LINE__, p, s) #define xstrdup(s) xxstrdup(__LINE__, s) #define free(p) xxfree(p) #endif /* Syntax and runtime errors. They always abort scripts. * In interactive use they usually discard unparsed and/or unexecuted commands * and return to the prompt. * HUSH_DEBUG >= 2 prints line number in this file where it was detected. */ #if HUSH_DEBUG < 2 # define die_if_script(lineno, ...) die_if_script(__VA_ARGS__) # define syntax_error(lineno, msg) syntax_error(msg) # define syntax_error_at(lineno, msg) syntax_error_at(msg) # define syntax_error_unterm_ch(lineno, ch) syntax_error_unterm_ch(ch) # define syntax_error_unterm_str(lineno, s) syntax_error_unterm_str(s) # define syntax_error_unexpected_ch(lineno, ch) syntax_error_unexpected_ch(ch) #endif static void die_if_script(unsigned lineno, const char *fmt, ...) { va_list p; #if HUSH_DEBUG >= 2 bb_error_msg("hush.c:%u", lineno); #endif va_start(p, fmt); bb_verror_msg(fmt, p, NULL); va_end(p); if (!G_interactive_fd) xfunc_die(); } static void syntax_error(unsigned lineno, const char *msg) { if (msg) die_if_script(lineno, "syntax error: %s", msg); else die_if_script(lineno, "syntax error", NULL); } static void syntax_error_at(unsigned lineno, const char *msg) { die_if_script(lineno, "syntax error at '%s'", msg); } static void syntax_error_unterm_str(unsigned lineno, const char *s) { die_if_script(lineno, "syntax error: unterminated %s", s); } /* It so happens that all such cases are totally fatal * even if shell is interactive: EOF while looking for closing * delimiter. There is nowhere to read stuff from after that, * it's EOF! The only choice is to terminate. */ static void syntax_error_unterm_ch(unsigned lineno, char ch) NORETURN; static void syntax_error_unterm_ch(unsigned lineno, char ch) { char msg[2] = { ch, '\0' }; syntax_error_unterm_str(lineno, msg); xfunc_die(); } static void syntax_error_unexpected_ch(unsigned lineno, int ch) { char msg[2]; msg[0] = ch; msg[1] = '\0'; die_if_script(lineno, "syntax error: unexpected %s", ch == EOF ? "EOF" : msg); } #if HUSH_DEBUG < 2 # undef die_if_script # undef syntax_error # undef syntax_error_at # undef syntax_error_unterm_ch # undef syntax_error_unterm_str # undef syntax_error_unexpected_ch #else # define die_if_script(...) die_if_script(__LINE__, __VA_ARGS__) # define syntax_error(msg) syntax_error(__LINE__, msg) # define syntax_error_at(msg) syntax_error_at(__LINE__, msg) # define syntax_error_unterm_ch(ch) syntax_error_unterm_ch(__LINE__, ch) # define syntax_error_unterm_str(s) syntax_error_unterm_str(__LINE__, s) # define syntax_error_unexpected_ch(ch) syntax_error_unexpected_ch(__LINE__, ch) #endif #if ENABLE_HUSH_INTERACTIVE static void cmdedit_update_prompt(void); #else # define cmdedit_update_prompt() ((void)0) #endif /* Utility functions */ /* Replace each \x with x in place, return ptr past NUL. */ static char *unbackslash(char *src) { char *dst = src = strchrnul(src, '\\'); while (1) { if (*src == '\\') src++; if ((*dst++ = *src++) == '\0') break; } return dst; } static char **add_strings_to_strings(char **strings, char **add, int need_to_dup) { int i; unsigned count1; unsigned count2; char **v; v = strings; count1 = 0; if (v) { while (*v) { count1++; v++; } } count2 = 0; v = add; while (*v) { count2++; v++; } v = xrealloc(strings, (count1 + count2 + 1) * sizeof(char*)); v[count1 + count2] = NULL; i = count2; while (--i >= 0) v[count1 + i] = (need_to_dup ? xstrdup(add[i]) : add[i]); return v; } #if LEAK_HUNTING static char **xx_add_strings_to_strings(int lineno, char **strings, char **add, int need_to_dup) { char **ptr = add_strings_to_strings(strings, add, need_to_dup); fdprintf(2, "line %d: add_strings_to_strings %p\n", lineno, ptr); return ptr; } #define add_strings_to_strings(strings, add, need_to_dup) \ xx_add_strings_to_strings(__LINE__, strings, add, need_to_dup) #endif /* Note: takes ownership of "add" ptr (it is not strdup'ed) */ static char **add_string_to_strings(char **strings, char *add) { char *v[2]; v[0] = add; v[1] = NULL; return add_strings_to_strings(strings, v, /*dup:*/ 0); } #if LEAK_HUNTING static char **xx_add_string_to_strings(int lineno, char **strings, char *add) { char **ptr = add_string_to_strings(strings, add); fdprintf(2, "line %d: add_string_to_strings %p\n", lineno, ptr); return ptr; } #define add_string_to_strings(strings, add) \ xx_add_string_to_strings(__LINE__, strings, add) #endif static void free_strings(char **strings) { char **v; if (!strings) return; v = strings; while (*v) { free(*v); v++; } free(strings); } /* Helpers for setting new $n and restoring them back */ typedef struct save_arg_t { char *sv_argv0; char **sv_g_argv; int sv_g_argc; smallint sv_g_malloced; } save_arg_t; static void save_and_replace_G_args(save_arg_t *sv, char **argv) { int n; sv->sv_argv0 = argv[0]; sv->sv_g_argv = G.global_argv; sv->sv_g_argc = G.global_argc; sv->sv_g_malloced = G.global_args_malloced; argv[0] = G.global_argv[0]; /* retain $0 */ G.global_argv = argv; G.global_args_malloced = 0; n = 1; while (*++argv) n++; G.global_argc = n; } static void restore_G_args(save_arg_t *sv, char **argv) { char **pp; if (G.global_args_malloced) { /* someone ran "set -- arg1 arg2 ...", undo */ pp = G.global_argv; while (*++pp) /* note: does not free $0 */ free(*pp); free(G.global_argv); } argv[0] = sv->sv_argv0; G.global_argv = sv->sv_g_argv; G.global_argc = sv->sv_g_argc; G.global_args_malloced = sv->sv_g_malloced; } /* Basic theory of signal handling in shell * ======================================== * This does not describe what hush does, rather, it is current understanding * what it _should_ do. If it doesn't, it's a bug. * http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#trap * * Signals are handled only after each pipe ("cmd | cmd | cmd" thing) * is finished or backgrounded. It is the same in interactive and * non-interactive shells, and is the same regardless of whether * a user trap handler is installed or a shell special one is in effect. * ^C or ^Z from keyboard seems to execute "at once" because it usually * backgrounds (i.e. stops) or kills all members of currently running * pipe. * * Wait builtin in interruptible by signals for which user trap is set * or by SIGINT in interactive shell. * * Trap handlers will execute even within trap handlers. (right?) * * User trap handlers are forgotten when subshell ("(cmd)") is entered, * except for handlers set to '' (empty string). * * If job control is off, backgrounded commands ("cmd &") * have SIGINT, SIGQUIT set to SIG_IGN. * * Commands which are run in command substitution ("`cmd`") * have SIGTTIN, SIGTTOU, SIGTSTP set to SIG_IGN. * * Ordinary commands have signals set to SIG_IGN/DFL as inherited * by the shell from its parent. * * Signals which differ from SIG_DFL action * (note: child (i.e., [v]forked) shell is not an interactive shell): * * SIGQUIT: ignore * SIGTERM (interactive): ignore * SIGHUP (interactive): * send SIGCONT to stopped jobs, send SIGHUP to all jobs and exit * SIGTTIN, SIGTTOU, SIGTSTP (if job control is on): ignore * Note that ^Z is handled not by trapping SIGTSTP, but by seeing * that all pipe members are stopped. Try this in bash: * while :; do :; done - ^Z does not background it * (while :; do :; done) - ^Z backgrounds it * SIGINT (interactive): wait for last pipe, ignore the rest * of the command line, show prompt. NB: ^C does not send SIGINT * to interactive shell while shell is waiting for a pipe, * since shell is bg'ed (is not in foreground process group). * Example 1: this waits 5 sec, but does not execute ls: * "echo $$; sleep 5; ls -l" + "kill -INT " * Example 2: this does not wait and does not execute ls: * "echo $$; sleep 5 & wait; ls -l" + "kill -INT " * Example 3: this does not wait 5 sec, but executes ls: * "sleep 5; ls -l" + press ^C * * (What happens to signals which are IGN on shell start?) * (What happens with signal mask on shell start?) * * Implementation in hush * ====================== * We use in-kernel pending signal mask to determine which signals were sent. * We block all signals which we don't want to take action immediately, * i.e. we block all signals which need to have special handling as described * above, and all signals which have traps set. * After each pipe execution, we extract any pending signals via sigtimedwait() * and act on them. * * unsigned non_DFL_mask: a mask of such "special" signals * sigset_t blocked_set: current blocked signal set * * "trap - SIGxxx": * clear bit in blocked_set unless it is also in non_DFL_mask * "trap 'cmd' SIGxxx": * set bit in blocked_set (even if 'cmd' is '') * after [v]fork, if we plan to be a shell: * unblock signals with special interactive handling * (child shell is not interactive), * unset all traps except '' (note: regardless of child shell's type - {}, (), etc) * after [v]fork, if we plan to exec: * POSIX says fork clears pending signal mask in child - no need to clear it. * Restore blocked signal set to one inherited by shell just prior to exec. * * Note: as a result, we do not use signal handlers much. The only uses * are to count SIGCHLDs * and to restore tty pgrp on signal-induced exit. * * Note 2 (compat): * Standard says "When a subshell is entered, traps that are not being ignored * are set to the default actions". bash interprets it so that traps which * are set to '' (ignore) are NOT reset to defaults. We do the same. */ enum { SPECIAL_INTERACTIVE_SIGS = 0 | (1 << SIGTERM) | (1 << SIGINT) | (1 << SIGHUP) , SPECIAL_JOB_SIGS = 0 #if ENABLE_HUSH_JOB | (1 << SIGTTIN) | (1 << SIGTTOU) | (1 << SIGTSTP) #endif }; #if ENABLE_HUSH_FAST static void SIGCHLD_handler(int sig UNUSED_PARAM) { G.count_SIGCHLD++; //bb_error_msg("[%d] SIGCHLD_handler: G.count_SIGCHLD:%d G.handled_SIGCHLD:%d", getpid(), G.count_SIGCHLD, G.handled_SIGCHLD); } #endif #if ENABLE_HUSH_JOB /* After [v]fork, in child: do not restore tty pgrp on xfunc death */ #define disable_restore_tty_pgrp_on_exit() (die_sleep = 0) /* After [v]fork, in parent: restore tty pgrp on xfunc death */ #define enable_restore_tty_pgrp_on_exit() (die_sleep = -1) /* Restores tty foreground process group, and exits. * May be called as signal handler for fatal signal * (will resend signal to itself, producing correct exit state) * or called directly with -EXITCODE. * We also call it if xfunc is exiting. */ static void sigexit(int sig) NORETURN; static void sigexit(int sig) { /* Disable all signals: job control, SIGPIPE, etc. */ sigprocmask_allsigs(SIG_BLOCK); /* Careful: we can end up here after [v]fork. Do not restore * tty pgrp then, only top-level shell process does that */ if (G_saved_tty_pgrp && getpid() == G.root_pid) tcsetpgrp(G_interactive_fd, G_saved_tty_pgrp); /* Not a signal, just exit */ if (sig <= 0) _exit(- sig); kill_myself_with_sig(sig); /* does not return */ } #else #define disable_restore_tty_pgrp_on_exit() ((void)0) #define enable_restore_tty_pgrp_on_exit() ((void)0) #endif /* Restores tty foreground process group, and exits. */ static void hush_exit(int exitcode) NORETURN; static void hush_exit(int exitcode) { if (G.exiting <= 0 && G.traps && G.traps[0] && G.traps[0][0]) { /* Prevent recursion: * trap "echo Hi; exit" EXIT; exit */ char *argv[] = { NULL, G.traps[0], NULL }; G.traps[0] = NULL; G.exiting = 1; builtin_eval(argv); free(argv[1]); } #if ENABLE_HUSH_JOB fflush_all(); sigexit(- (exitcode & 0xff)); #else exit(exitcode); #endif } static int check_and_run_traps(int sig) { static const struct timespec zero_timespec = { 0, 0 }; smalluint save_rcode; int last_sig = 0; if (sig) goto jump_in; while (1) { sig = sigtimedwait(&G.blocked_set, NULL, &zero_timespec); if (sig <= 0) break; jump_in: last_sig = sig; if (G.traps && G.traps[sig]) { if (G.traps[sig][0]) { /* We have user-defined handler */ char *argv[] = { NULL, xstrdup(G.traps[sig]), NULL }; save_rcode = G.last_exitcode; builtin_eval(argv); free(argv[1]); G.last_exitcode = save_rcode; } /* else: "" trap, ignoring signal */ continue; } /* not a trap: special action */ switch (sig) { #if ENABLE_HUSH_FAST case SIGCHLD: G.count_SIGCHLD++; //bb_error_msg("[%d] check_and_run_traps: G.count_SIGCHLD:%d G.handled_SIGCHLD:%d", getpid(), G.count_SIGCHLD, G.handled_SIGCHLD); break; #endif case SIGINT: /* Builtin was ^C'ed, make it look prettier: */ bb_putchar('\n'); G.flag_SIGINT = 1; break; #if ENABLE_HUSH_JOB case SIGHUP: { struct pipe *job; /* bash is observed to signal whole process groups, * not individual processes */ for (job = G.job_list; job; job = job->next) { if (job->pgrp <= 0) continue; debug_printf_exec("HUPing pgrp %d\n", job->pgrp); if (kill(- job->pgrp, SIGHUP) == 0) kill(- job->pgrp, SIGCONT); } sigexit(SIGHUP); } #endif default: /* ignored: */ /* SIGTERM, SIGQUIT, SIGTTIN, SIGTTOU, SIGTSTP */ break; } } return last_sig; } static const char *get_cwd(int force) { if (force || G.cwd == NULL) { /* xrealloc_getcwd_or_warn(arg) calls free(arg), * we must not try to free(bb_msg_unknown) */ if (G.cwd == bb_msg_unknown) G.cwd = NULL; G.cwd = xrealloc_getcwd_or_warn((char *)G.cwd); if (!G.cwd) G.cwd = bb_msg_unknown; } return G.cwd; } /* * Shell and environment variable support */ static struct variable **get_ptr_to_local_var(const char *name) { struct variable **pp; struct variable *cur; int len; len = strlen(name); pp = &G.top_var; while ((cur = *pp) != NULL) { if (strncmp(cur->varstr, name, len) == 0 && cur->varstr[len] == '=') return pp; pp = &cur->next; } return NULL; } static struct variable *get_local_var(const char *name) { struct variable **pp = get_ptr_to_local_var(name); if (pp) return *pp; return NULL; } static const char* FAST_FUNC get_local_var_value(const char *name) { struct variable **pp = get_ptr_to_local_var(name); if (pp) return strchr((*pp)->varstr, '=') + 1; if (strcmp(name, "PPID") == 0) return utoa(G.root_ppid); // bash compat: UID? EUID? #if ENABLE_HUSH_RANDOM_SUPPORT if (strcmp(name, "RANDOM") == 0) { return utoa(next_random(&G.random_gen)); } #endif return NULL; } /* str holds "NAME=VAL" and is expected to be malloced. * We take ownership of it. * flg_export: * 0: do not change export flag * (if creating new variable, flag will be 0) * 1: set export flag and putenv the variable * -1: clear export flag and unsetenv the variable * flg_read_only is set only when we handle -R var=val */ #if !BB_MMU && ENABLE_HUSH_LOCAL /* all params are used */ #elif BB_MMU && ENABLE_HUSH_LOCAL #define set_local_var(str, flg_export, local_lvl, flg_read_only) \ set_local_var(str, flg_export, local_lvl) #elif BB_MMU && !ENABLE_HUSH_LOCAL #define set_local_var(str, flg_export, local_lvl, flg_read_only) \ set_local_var(str, flg_export) #elif !BB_MMU && !ENABLE_HUSH_LOCAL #define set_local_var(str, flg_export, local_lvl, flg_read_only) \ set_local_var(str, flg_export, flg_read_only) #endif static int set_local_var(char *str, int flg_export, int local_lvl, int flg_read_only) { struct variable **var_pp; struct variable *cur; char *eq_sign; int name_len; eq_sign = strchr(str, '='); if (!eq_sign) { /* not expected to ever happen? */ free(str); return -1; } name_len = eq_sign - str + 1; /* including '=' */ var_pp = &G.top_var; while ((cur = *var_pp) != NULL) { if (strncmp(cur->varstr, str, name_len) != 0) { var_pp = &cur->next; continue; } /* We found an existing var with this name */ if (cur->flg_read_only) { #if !BB_MMU if (!flg_read_only) #endif bb_error_msg("%s: readonly variable", str); free(str); return -1; } if (flg_export == -1) { // "&& cur->flg_export" ? debug_printf_env("%s: unsetenv '%s'\n", __func__, str); *eq_sign = '\0'; unsetenv(str); *eq_sign = '='; } #if ENABLE_HUSH_LOCAL if (cur->func_nest_level < local_lvl) { /* New variable is declared as local, * and existing one is global, or local * from enclosing function. * Remove and save old one: */ *var_pp = cur->next; cur->next = *G.shadowed_vars_pp; *G.shadowed_vars_pp = cur; /* bash 3.2.33(1) and exported vars: * # export z=z * # f() { local z=a; env | grep ^z; } * # f * z=a * # env | grep ^z * z=z */ if (cur->flg_export) flg_export = 1; break; } #endif if (strcmp(cur->varstr + name_len, eq_sign + 1) == 0) { free_and_exp: free(str); goto exp; } if (cur->max_len != 0) { if (cur->max_len >= strlen(str)) { /* This one is from startup env, reuse space */ strcpy(cur->varstr, str); goto free_and_exp; } } else { /* max_len == 0 signifies "malloced" var, which we can * (and has to) free */ free(cur->varstr); } cur->max_len = 0; goto set_str_and_exp; } /* Not found - create new variable struct */ cur = xzalloc(sizeof(*cur)); #if ENABLE_HUSH_LOCAL cur->func_nest_level = local_lvl; #endif cur->next = *var_pp; *var_pp = cur; set_str_and_exp: cur->varstr = str; #if !BB_MMU cur->flg_read_only = flg_read_only; #endif exp: if (flg_export == 1) cur->flg_export = 1; if (name_len == 4 && cur->varstr[0] == 'P' && cur->varstr[1] == 'S') cmdedit_update_prompt(); if (cur->flg_export) { if (flg_export == -1) { cur->flg_export = 0; /* unsetenv was already done */ } else { debug_printf_env("%s: putenv '%s'\n", __func__, cur->varstr); return putenv(cur->varstr); } } return 0; } /* Used at startup and after each cd */ static void set_pwd_var(int exp) { set_local_var(xasprintf("PWD=%s", get_cwd(/*force:*/ 1)), /*exp:*/ exp, /*lvl:*/ 0, /*ro:*/ 0); } static int unset_local_var_len(const char *name, int name_len) { struct variable *cur; struct variable **var_pp; if (!name) return EXIT_SUCCESS; var_pp = &G.top_var; while ((cur = *var_pp) != NULL) { if (strncmp(cur->varstr, name, name_len) == 0 && cur->varstr[name_len] == '=') { if (cur->flg_read_only) { bb_error_msg("%s: readonly variable", name); return EXIT_FAILURE; } *var_pp = cur->next; debug_printf_env("%s: unsetenv '%s'\n", __func__, cur->varstr); bb_unsetenv(cur->varstr); if (name_len == 3 && cur->varstr[0] == 'P' && cur->varstr[1] == 'S') cmdedit_update_prompt(); if (!cur->max_len) free(cur->varstr); free(cur); return EXIT_SUCCESS; } var_pp = &cur->next; } return EXIT_SUCCESS; } static int unset_local_var(const char *name) { return unset_local_var_len(name, strlen(name)); } static void unset_vars(char **strings) { char **v; if (!strings) return; v = strings; while (*v) { const char *eq = strchrnul(*v, '='); unset_local_var_len(*v, (int)(eq - *v)); v++; } free(strings); } #if ENABLE_SH_MATH_SUPPORT #define is_name(c) ((c) == '_' || isalpha((unsigned char)(c))) #define is_in_name(c) ((c) == '_' || isalnum((unsigned char)(c))) static char* FAST_FUNC endofname(const char *name) { char *p; p = (char *) name; if (!is_name(*p)) return p; while (*++p) { if (!is_in_name(*p)) break; } return p; } #endif static void FAST_FUNC set_local_var_from_halves(const char *name, const char *val) { char *var = xasprintf("%s=%s", name, val); set_local_var(var, /*flags:*/ 0, /*lvl:*/ 0, /*ro:*/ 0); } /* * Helpers for "var1=val1 var2=val2 cmd" feature */ static void add_vars(struct variable *var) { struct variable *next; while (var) { next = var->next; var->next = G.top_var; G.top_var = var; if (var->flg_export) { debug_printf_env("%s: restoring exported '%s'\n", __func__, var->varstr); putenv(var->varstr); } else { debug_printf_env("%s: restoring variable '%s'\n", __func__, var->varstr); } var = next; } } static struct variable *set_vars_and_save_old(char **strings) { char **s; struct variable *old = NULL; if (!strings) return old; s = strings; while (*s) { struct variable *var_p; struct variable **var_pp; char *eq; eq = strchr(*s, '='); if (eq) { *eq = '\0'; var_pp = get_ptr_to_local_var(*s); *eq = '='; if (var_pp) { /* Remove variable from global linked list */ var_p = *var_pp; debug_printf_env("%s: removing '%s'\n", __func__, var_p->varstr); *var_pp = var_p->next; /* Add it to returned list */ var_p->next = old; old = var_p; } set_local_var(*s, /*exp:*/ 1, /*lvl:*/ 0, /*ro:*/ 0); } s++; } return old; } /* * in_str support */ static int FAST_FUNC static_get(struct in_str *i) { int ch = *i->p++; if (ch != '\0') return ch; i->p--; return EOF; } static int FAST_FUNC static_peek(struct in_str *i) { return *i->p; } #if ENABLE_HUSH_INTERACTIVE static void cmdedit_update_prompt(void) { if (ENABLE_FEATURE_EDITING_FANCY_PROMPT) { G.PS1 = get_local_var_value("PS1"); if (G.PS1 == NULL) G.PS1 = "\\w \\$ "; G.PS2 = get_local_var_value("PS2"); } else { G.PS1 = NULL; } if (G.PS2 == NULL) G.PS2 = "> "; } static const char* setup_prompt_string(int promptmode) { const char *prompt_str; debug_printf("setup_prompt_string %d ", promptmode); if (!ENABLE_FEATURE_EDITING_FANCY_PROMPT) { /* Set up the prompt */ if (promptmode == 0) { /* PS1 */ free((char*)G.PS1); /* bash uses $PWD value, even if it is set by user. * It uses current dir only if PWD is unset. * We always use current dir. */ G.PS1 = xasprintf("%s %c ", get_cwd(0), (geteuid() != 0) ? '$' : '#'); prompt_str = G.PS1; } else prompt_str = G.PS2; } else prompt_str = (promptmode == 0) ? G.PS1 : G.PS2; debug_printf("result '%s'\n", prompt_str); return prompt_str; } static void get_user_input(struct in_str *i) { int r; const char *prompt_str; prompt_str = setup_prompt_string(i->promptmode); #if ENABLE_FEATURE_EDITING /* Enable command line editing only while a command line * is actually being read */ do { G.flag_SIGINT = 0; /* buglet: SIGINT will not make new prompt to appear _at once_, * only after . (^C will work) */ r = read_line_input(prompt_str, G.user_input_buf, CONFIG_FEATURE_EDITING_MAX_LEN-1, G.line_input_state); /* catch *SIGINT* etc (^C is handled by read_line_input) */ check_and_run_traps(0); } while (r == 0 || G.flag_SIGINT); /* repeat if ^C or SIGINT */ i->eof_flag = (r < 0); if (i->eof_flag) { /* EOF/error detected */ G.user_input_buf[0] = EOF; /* yes, it will be truncated, it's ok */ G.user_input_buf[1] = '\0'; } #else do { G.flag_SIGINT = 0; fputs(prompt_str, stdout); fflush_all(); G.user_input_buf[0] = r = fgetc(i->file); /*G.user_input_buf[1] = '\0'; - already is and never changed */ //do we need check_and_run_traps(0)? (maybe only if stdin) } while (G.flag_SIGINT); i->eof_flag = (r == EOF); #endif i->p = G.user_input_buf; } #endif /* INTERACTIVE */ /* This is the magic location that prints prompts * and gets data back from the user */ static int FAST_FUNC file_get(struct in_str *i) { int ch; /* If there is data waiting, eat it up */ if (i->p && *i->p) { #if ENABLE_HUSH_INTERACTIVE take_cached: #endif ch = *i->p++; if (i->eof_flag && !*i->p) ch = EOF; /* note: ch is never NUL */ } else { /* need to double check i->file because we might be doing something * more complicated by now, like sourcing or substituting. */ #if ENABLE_HUSH_INTERACTIVE if (G_interactive_fd && i->promptme && i->file == stdin) { do { get_user_input(i); } while (!*i->p); /* need non-empty line */ i->promptmode = 1; /* PS2 */ i->promptme = 0; goto take_cached; } #endif do ch = fgetc(i->file); while (ch == '\0'); } debug_printf("file_get: got '%c' %d\n", ch, ch); #if ENABLE_HUSH_INTERACTIVE if (ch == '\n') i->promptme = 1; #endif return ch; } /* All callers guarantee this routine will never * be used right after a newline, so prompting is not needed. */ static int FAST_FUNC file_peek(struct in_str *i) { int ch; if (i->p && *i->p) { if (i->eof_flag && !i->p[1]) return EOF; return *i->p; /* note: ch is never NUL */ } do ch = fgetc(i->file); while (ch == '\0'); i->eof_flag = (ch == EOF); i->peek_buf[0] = ch; i->peek_buf[1] = '\0'; i->p = i->peek_buf; debug_printf("file_peek: got '%c' %d\n", ch, ch); return ch; } static void setup_file_in_str(struct in_str *i, FILE *f) { i->peek = file_peek; i->get = file_get; #if ENABLE_HUSH_INTERACTIVE i->promptme = 1; i->promptmode = 0; /* PS1 */ #endif i->file = f; i->p = NULL; } static void setup_string_in_str(struct in_str *i, const char *s) { i->peek = static_peek; i->get = static_get; #if ENABLE_HUSH_INTERACTIVE i->promptme = 1; i->promptmode = 0; /* PS1 */ #endif i->p = s; i->eof_flag = 0; } /* * o_string support */ #define B_CHUNK (32 * sizeof(char*)) static void o_reset_to_empty_unquoted(o_string *o) { o->length = 0; o->o_quoted = 0; if (o->data) o->data[0] = '\0'; } static void o_free(o_string *o) { free(o->data); memset(o, 0, sizeof(*o)); } static ALWAYS_INLINE void o_free_unsafe(o_string *o) { free(o->data); } static void o_grow_by(o_string *o, int len) { if (o->length + len > o->maxlen) { o->maxlen += (2*len > B_CHUNK ? 2*len : B_CHUNK); o->data = xrealloc(o->data, 1 + o->maxlen); } } static void o_addchr(o_string *o, int ch) { debug_printf("o_addchr: '%c' o->length=%d o=%p\n", ch, o->length, o); o_grow_by(o, 1); o->data[o->length] = ch; o->length++; o->data[o->length] = '\0'; } static void o_addblock(o_string *o, const char *str, int len) { o_grow_by(o, len); memcpy(&o->data[o->length], str, len); o->length += len; o->data[o->length] = '\0'; } #if !BB_MMU static void o_addstr(o_string *o, const char *str) { o_addblock(o, str, strlen(str)); } static void nommu_addchr(o_string *o, int ch) { if (o) o_addchr(o, ch); } #else # define nommu_addchr(o, str) ((void)0) #endif static void o_addstr_with_NUL(o_string *o, const char *str) { o_addblock(o, str, strlen(str) + 1); } static void o_addblock_duplicate_backslash(o_string *o, const char *str, int len) { while (len) { o_addchr(o, *str); if (*str++ == '\\' && (*str != '*' && *str != '?' && *str != '[') ) { o_addchr(o, '\\'); } len--; } } #undef HUSH_BRACE_EXP /* * HUSH_BRACE_EXP code needs corresponding quoting on variable expansion side. * Currently, "v='{q,w}'; echo $v" erroneously expands braces in $v. * Apparently, on unquoted $v bash still does globbing * ("v='*.txt'; echo $v" prints all .txt files), * but NOT brace expansion! Thus, there should be TWO independent * quoting mechanisms on $v expansion side: one protects * $v from brace expansion, and other additionally protects "$v" against globbing. * We have only second one. */ #ifdef HUSH_BRACE_EXP # define MAYBE_BRACES "{}" #else # define MAYBE_BRACES "" #endif /* My analysis of quoting semantics tells me that state information * is associated with a destination, not a source. */ static void o_addqchr(o_string *o, int ch) { int sz = 1; char *found = strchr("*?[\\" MAYBE_BRACES, ch); if (found) sz++; o_grow_by(o, sz); if (found) { o->data[o->length] = '\\'; o->length++; } o->data[o->length] = ch; o->length++; o->data[o->length] = '\0'; } static void o_addQchr(o_string *o, int ch) { int sz = 1; if (o->o_escape && strchr("*?[\\" MAYBE_BRACES, ch)) { sz++; o->data[o->length] = '\\'; o->length++; } o_grow_by(o, sz); o->data[o->length] = ch; o->length++; o->data[o->length] = '\0'; } static void o_addQstr(o_string *o, const char *str, int len) { if (!o->o_escape) { o_addblock(o, str, len); return; } while (len) { char ch; int sz; int ordinary_cnt = strcspn(str, "*?[\\" MAYBE_BRACES); if (ordinary_cnt > len) /* paranoia */ ordinary_cnt = len; o_addblock(o, str, ordinary_cnt); if (ordinary_cnt == len) return; str += ordinary_cnt; len -= ordinary_cnt + 1; /* we are processing + 1 char below */ ch = *str++; sz = 1; if (ch) { /* it is necessarily one of "*?[\\" MAYBE_BRACES */ sz++; o->data[o->length] = '\\'; o->length++; } o_grow_by(o, sz); o->data[o->length] = ch; o->length++; o->data[o->length] = '\0'; } } /* A special kind of o_string for $VAR and `cmd` expansion. * It contains char* list[] at the beginning, which is grown in 16 element * increments. Actual string data starts at the next multiple of 16 * (char*). * list[i] contains an INDEX (int!) into this string data. * It means that if list[] needs to grow, data needs to be moved higher up * but list[i]'s need not be modified. * NB: remembering how many list[i]'s you have there is crucial. * o_finalize_list() operation post-processes this structure - calculates * and stores actual char* ptrs in list[]. Oh, it NULL terminates it as well. */ #if DEBUG_EXPAND || DEBUG_GLOB static void debug_print_list(const char *prefix, o_string *o, int n) { char **list = (char**)o->data; int string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]); int i = 0; indent(); fprintf(stderr, "%s: list:%p n:%d string_start:%d length:%d maxlen:%d\n", prefix, list, n, string_start, o->length, o->maxlen); while (i < n) { indent(); fprintf(stderr, " list[%d]=%d '%s' %p\n", i, (int)list[i], o->data + (int)list[i] + string_start, o->data + (int)list[i] + string_start); i++; } if (n) { const char *p = o->data + (int)list[n - 1] + string_start; indent(); fprintf(stderr, " total_sz:%ld\n", (long)((p + strlen(p) + 1) - o->data)); } } #else # define debug_print_list(prefix, o, n) ((void)0) #endif /* n = o_save_ptr_helper(str, n) "starts new string" by storing an index value * in list[n] so that it points past last stored byte so far. * It returns n+1. */ static int o_save_ptr_helper(o_string *o, int n) { char **list = (char**)o->data; int string_start; int string_len; if (!o->has_empty_slot) { string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]); string_len = o->length - string_start; if (!(n & 0xf)) { /* 0, 0x10, 0x20...? */ debug_printf_list("list[%d]=%d string_start=%d (growing)\n", n, string_len, string_start); /* list[n] points to string_start, make space for 16 more pointers */ o->maxlen += 0x10 * sizeof(list[0]); o->data = xrealloc(o->data, o->maxlen + 1); list = (char**)o->data; memmove(list + n + 0x10, list + n, string_len); o->length += 0x10 * sizeof(list[0]); } else { debug_printf_list("list[%d]=%d string_start=%d\n", n, string_len, string_start); } } else { /* We have empty slot at list[n], reuse without growth */ string_start = ((n+1 + 0xf) & ~0xf) * sizeof(list[0]); /* NB: n+1! */ string_len = o->length - string_start; debug_printf_list("list[%d]=%d string_start=%d (empty slot)\n", n, string_len, string_start); o->has_empty_slot = 0; } list[n] = (char*)(ptrdiff_t)string_len; return n + 1; } /* "What was our last o_save_ptr'ed position (byte offset relative o->data)?" */ static int o_get_last_ptr(o_string *o, int n) { char **list = (char**)o->data; int string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]); return ((int)(ptrdiff_t)list[n-1]) + string_start; } #ifdef HUSH_BRACE_EXP /* There in a GNU extension, GLOB_BRACE, but it is not usable: * first, it processes even {a} (no commas), second, * I didn't manage to make it return strings when they don't match * existing files. Need to re-implement it. */ /* Helper */ static int glob_needed(const char *s) { while (*s) { if (*s == '\\') { if (!s[1]) return 0; s += 2; continue; } if (*s == '*' || *s == '[' || *s == '?' || *s == '{') return 1; s++; } return 0; } /* Return pointer to next closing brace or to comma */ static const char *next_brace_sub(const char *cp) { unsigned depth = 0; cp++; while (*cp != '\0') { if (*cp == '\\') { if (*++cp == '\0') break; cp++; continue; } /*{*/ if ((*cp == '}' && depth-- == 0) || (*cp == ',' && depth == 0)) break; if (*cp++ == '{') /*}*/ depth++; } return *cp != '\0' ? cp : NULL; } /* Recursive brace globber. Note: may garble pattern[]. */ static int glob_brace(char *pattern, o_string *o, int n) { char *new_pattern_buf; const char *begin; const char *next; const char *rest; const char *p; size_t rest_len; debug_printf_glob("glob_brace('%s')\n", pattern); begin = pattern; while (1) { if (*begin == '\0') goto simple_glob; if (*begin == '{') /*}*/ { /* Find the first sub-pattern and at the same time * find the rest after the closing brace */ next = next_brace_sub(begin); if (next == NULL) { /* An illegal expression */ goto simple_glob; } /*{*/ if (*next == '}') { /* "{abc}" with no commas - illegal * brace expr, disregard and skip it */ begin = next + 1; continue; } break; } if (*begin == '\\' && begin[1] != '\0') begin++; begin++; } debug_printf_glob("begin:%s\n", begin); debug_printf_glob("next:%s\n", next); /* Now find the end of the whole brace expression */ rest = next; /*{*/ while (*rest != '}') { rest = next_brace_sub(rest); if (rest == NULL) { /* An illegal expression */ goto simple_glob; } debug_printf_glob("rest:%s\n", rest); } rest_len = strlen(++rest) + 1; /* We are sure the brace expression is well-formed */ /* Allocate working buffer large enough for our work */ new_pattern_buf = xmalloc(strlen(pattern)); /* We have a brace expression. BEGIN points to the opening {, * NEXT points past the terminator of the first element, and REST * points past the final }. We will accumulate result names from * recursive runs for each brace alternative in the buffer using * GLOB_APPEND. */ p = begin + 1; while (1) { /* Construct the new glob expression */ memcpy( mempcpy( mempcpy(new_pattern_buf, /* We know the prefix for all sub-patterns */ pattern, begin - pattern), p, next - p), rest, rest_len); /* Note: glob_brace() may garble new_pattern_buf[]. * That's why we re-copy prefix every time (1st memcpy above). */ n = glob_brace(new_pattern_buf, o, n); /*{*/ if (*next == '}') { /* We saw the last entry */ break; } p = next + 1; next = next_brace_sub(next); } free(new_pattern_buf); return n; simple_glob: { int gr; glob_t globdata; memset(&globdata, 0, sizeof(globdata)); gr = glob(pattern, 0, NULL, &globdata); debug_printf_glob("glob('%s'):%d\n", pattern, gr); if (gr != 0) { if (gr == GLOB_NOMATCH) { globfree(&globdata); /* NB: garbles parameter */ unbackslash(pattern); o_addstr_with_NUL(o, pattern); debug_printf_glob("glob pattern '%s' is literal\n", pattern); return o_save_ptr_helper(o, n); } if (gr == GLOB_NOSPACE) bb_error_msg_and_die(bb_msg_memory_exhausted); /* GLOB_ABORTED? Only happens with GLOB_ERR flag, * but we didn't specify it. Paranoia again. */ bb_error_msg_and_die("glob error %d on '%s'", gr, pattern); } if (globdata.gl_pathv && globdata.gl_pathv[0]) { char **argv = globdata.gl_pathv; while (1) { o_addstr_with_NUL(o, *argv); n = o_save_ptr_helper(o, n); argv++; if (!*argv) break; } } globfree(&globdata); } return n; } /* Performs globbing on last list[], * saving each result as a new list[]. */ static int o_glob(o_string *o, int n) { char *pattern, *copy; debug_printf_glob("start o_glob: n:%d o->data:%p\n", n, o->data); if (!o->data) return o_save_ptr_helper(o, n); pattern = o->data + o_get_last_ptr(o, n); debug_printf_glob("glob pattern '%s'\n", pattern); if (!glob_needed(pattern)) { /* unbackslash last string in o in place, fix length */ o->length = unbackslash(pattern) - o->data; debug_printf_glob("glob pattern '%s' is literal\n", pattern); return o_save_ptr_helper(o, n); } copy = xstrdup(pattern); /* "forget" pattern in o */ o->length = pattern - o->data; n = glob_brace(copy, o, n); free(copy); if (DEBUG_GLOB) debug_print_list("o_glob returning", o, n); return n; } #else /* Helper */ static int glob_needed(const char *s) { while (*s) { if (*s == '\\') { if (!s[1]) return 0; s += 2; continue; } if (*s == '*' || *s == '[' || *s == '?') return 1; s++; } return 0; } /* Performs globbing on last list[], * saving each result as a new list[]. */ static int o_glob(o_string *o, int n) { glob_t globdata; int gr; char *pattern; debug_printf_glob("start o_glob: n:%d o->data:%p\n", n, o->data); if (!o->data) return o_save_ptr_helper(o, n); pattern = o->data + o_get_last_ptr(o, n); debug_printf_glob("glob pattern '%s'\n", pattern); if (!glob_needed(pattern)) { literal: /* unbackslash last string in o in place, fix length */ o->length = unbackslash(pattern) - o->data; debug_printf_glob("glob pattern '%s' is literal\n", pattern); return o_save_ptr_helper(o, n); } memset(&globdata, 0, sizeof(globdata)); /* Can't use GLOB_NOCHECK: it does not unescape the string. * If we glob "*.\*" and don't find anything, we need * to fall back to using literal "*.*", but GLOB_NOCHECK * will return "*.\*"! */ gr = glob(pattern, 0, NULL, &globdata); debug_printf_glob("glob('%s'):%d\n", pattern, gr); if (gr != 0) { if (gr == GLOB_NOMATCH) { globfree(&globdata); goto literal; } if (gr == GLOB_NOSPACE) bb_error_msg_and_die(bb_msg_memory_exhausted); /* GLOB_ABORTED? Only happens with GLOB_ERR flag, * but we didn't specify it. Paranoia again. */ bb_error_msg_and_die("glob error %d on '%s'", gr, pattern); } if (globdata.gl_pathv && globdata.gl_pathv[0]) { char **argv = globdata.gl_pathv; /* "forget" pattern in o */ o->length = pattern - o->data; while (1) { o_addstr_with_NUL(o, *argv); n = o_save_ptr_helper(o, n); argv++; if (!*argv) break; } } globfree(&globdata); if (DEBUG_GLOB) debug_print_list("o_glob returning", o, n); return n; } #endif /* If o->o_glob == 1, glob the string so far remembered. * Otherwise, just finish current list[] and start new */ static int o_save_ptr(o_string *o, int n) { if (o->o_glob) { /* if globbing is requested */ /* If o->has_empty_slot, list[n] was already globbed * (if it was requested back then when it was filled) * so don't do that again! */ if (!o->has_empty_slot) return o_glob(o, n); /* o_save_ptr_helper is inside */ } return o_save_ptr_helper(o, n); } /* "Please convert list[n] to real char* ptrs, and NULL terminate it." */ static char **o_finalize_list(o_string *o, int n) { char **list; int string_start; n = o_save_ptr(o, n); /* force growth for list[n] if necessary */ if (DEBUG_EXPAND) debug_print_list("finalized", o, n); debug_printf_expand("finalized n:%d\n", n); list = (char**)o->data; string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]); list[--n] = NULL; while (n) { n--; list[n] = o->data + (int)(ptrdiff_t)list[n] + string_start; } return list; } /* Expansion can recurse */ #if ENABLE_HUSH_TICK static int process_command_subs(o_string *dest, const char *s); #endif static char *expand_string_to_string(const char *str); #if BB_MMU #define parse_stream_dquoted(as_string, dest, input, dquote_end) \ parse_stream_dquoted(dest, input, dquote_end) #endif static int parse_stream_dquoted(o_string *as_string, o_string *dest, struct in_str *input, int dquote_end); /* expand_strvec_to_strvec() takes a list of strings, expands * all variable references within and returns a pointer to * a list of expanded strings, possibly with larger number * of strings. (Think VAR="a b"; echo $VAR). * This new list is allocated as a single malloc block. * NULL-terminated list of char* pointers is at the beginning of it, * followed by strings themself. * Caller can deallocate entire list by single free(list). */ /* Store given string, finalizing the word and starting new one whenever * we encounter IFS char(s). This is used for expanding variable values. * End-of-string does NOT finalize word: think about 'echo -$VAR-' */ static int expand_on_ifs(o_string *output, int n, const char *str) { while (1) { int word_len = strcspn(str, G.ifs); if (word_len) { if (output->o_escape || !output->o_glob) o_addQstr(output, str, word_len); else /* protect backslashes against globbing up :) */ o_addblock_duplicate_backslash(output, str, word_len); str += word_len; } if (!*str) /* EOL - do not finalize word */ break; o_addchr(output, '\0'); debug_print_list("expand_on_ifs", output, n); n = o_save_ptr(output, n); str += strspn(str, G.ifs); /* skip ifs chars */ } debug_print_list("expand_on_ifs[1]", output, n); return n; } /* Helper to expand $((...)) and heredoc body. These act as if * they are in double quotes, with the exception that they are not :). * Just the rules are similar: "expand only $var and `cmd`" * * Returns malloced string. * As an optimization, we return NULL if expansion is not needed. */ static char *expand_pseudo_dquoted(const char *str) { char *exp_str; struct in_str input; o_string dest = NULL_O_STRING; if (strchr(str, '$') == NULL #if ENABLE_HUSH_TICK && strchr(str, '`') == NULL #endif ) { return NULL; } /* We need to expand. Example: * echo $(($a + `echo 1`)) $((1 + $((2)) )) */ setup_string_in_str(&input, str); parse_stream_dquoted(NULL, &dest, &input, EOF); //bb_error_msg("'%s' -> '%s'", str, dest.data); exp_str = expand_string_to_string(dest.data); //bb_error_msg("'%s' -> '%s'", dest.data, exp_str); o_free_unsafe(&dest); return exp_str; } /* Expand all variable references in given string, adding words to list[] * at n, n+1,... positions. Return updated n (so that list[n] is next one * to be filled). This routine is extremely tricky: has to deal with * variables/parameters with whitespace, $* and $@, and constructs like * 'echo -$*-'. If you play here, you must run testsuite afterwards! */ static NOINLINE int expand_vars_to_list(o_string *output, int n, char *arg, char or_mask) { /* or_mask is either 0 (normal case) or 0x80 - * expansion of right-hand side of assignment == 1-element expand. * It will also do no globbing, and thus we must not backslash-quote! */ char ored_ch; char *p; ored_ch = 0; debug_printf_expand("expand_vars_to_list: arg:'%s' or_mask:%x\n", arg, or_mask); debug_print_list("expand_vars_to_list", output, n); n = o_save_ptr(output, n); debug_print_list("expand_vars_to_list[0]", output, n); while ((p = strchr(arg, SPECIAL_VAR_SYMBOL)) != NULL) { char first_ch; int i; char *dyn_val = NULL; const char *val = NULL; #if ENABLE_HUSH_TICK o_string subst_result = NULL_O_STRING; #endif #if ENABLE_SH_MATH_SUPPORT char arith_buf[sizeof(arith_t)*3 + 2]; #endif o_addblock(output, arg, p - arg); debug_print_list("expand_vars_to_list[1]", output, n); arg = ++p; p = strchr(p, SPECIAL_VAR_SYMBOL); first_ch = arg[0] | or_mask; /* forced to "quoted" if or_mask = 0x80 */ /* "$@" is special. Even if quoted, it can still * expand to nothing (not even an empty string) */ if ((first_ch & 0x7f) != '@') ored_ch |= first_ch; switch (first_ch & 0x7f) { /* Highest bit in first_ch indicates that var is double-quoted */ case '$': /* pid */ val = utoa(G.root_pid); break; case '!': /* bg pid */ val = G.last_bg_pid ? utoa(G.last_bg_pid) : (char*)""; break; case '?': /* exitcode */ val = utoa(G.last_exitcode); break; case '#': /* argc */ if (arg[1] != SPECIAL_VAR_SYMBOL) /* actually, it's a ${#var} */ goto case_default; val = utoa(G.global_argc ? G.global_argc-1 : 0); break; case '*': case '@': i = 1; if (!G.global_argv[i]) break; ored_ch |= first_ch; /* do it for "$@" _now_, when we know it's not empty */ if (!(first_ch & 0x80)) { /* unquoted $* or $@ */ smallint sv = output->o_escape; /* unquoted var's contents should be globbed, so don't escape */ output->o_escape = 0; while (G.global_argv[i]) { n = expand_on_ifs(output, n, G.global_argv[i]); debug_printf_expand("expand_vars_to_list: argv %d (last %d)\n", i, G.global_argc - 1); if (G.global_argv[i++][0] && G.global_argv[i]) { /* this argv[] is not empty and not last: * put terminating NUL, start new word */ o_addchr(output, '\0'); debug_print_list("expand_vars_to_list[2]", output, n); n = o_save_ptr(output, n); debug_print_list("expand_vars_to_list[3]", output, n); } } output->o_escape = sv; } else /* If or_mask is nonzero, we handle assignment 'a=....$@.....' * and in this case should treat it like '$*' - see 'else...' below */ if (first_ch == ('@'|0x80) && !or_mask) { /* quoted $@ */ while (1) { o_addQstr(output, G.global_argv[i], strlen(G.global_argv[i])); if (++i >= G.global_argc) break; o_addchr(output, '\0'); debug_print_list("expand_vars_to_list[4]", output, n); n = o_save_ptr(output, n); } } else { /* quoted $*: add as one word */ while (1) { o_addQstr(output, G.global_argv[i], strlen(G.global_argv[i])); if (!G.global_argv[++i]) break; if (G.ifs[0]) o_addchr(output, G.ifs[0]); } } break; case SPECIAL_VAR_SYMBOL: /* */ /* "Empty variable", used to make "" etc to not disappear */ arg++; ored_ch = 0x80; break; #if ENABLE_HUSH_TICK case '`': /* `cmd */ *p = '\0'; arg++; /* Can't just stuff it into output o_string, * expanded result may need to be globbed * and $IFS-splitted */ debug_printf_subst("SUBST '%s' first_ch %x\n", arg, first_ch); G.last_exitcode = process_command_subs(&subst_result, arg); debug_printf_subst("SUBST RES '%s'\n", subst_result.data); val = subst_result.data; goto store_val; #endif #if ENABLE_SH_MATH_SUPPORT case '+': { /* +cmd */ arith_eval_hooks_t hooks; arith_t res; int errcode; char *exp_str; arg++; /* skip '+' */ *p = '\0'; /* replace trailing */ debug_printf_subst("ARITH '%s' first_ch %x\n", arg, first_ch); exp_str = expand_pseudo_dquoted(arg); hooks.lookupvar = get_local_var_value; hooks.setvar = set_local_var_from_halves; hooks.endofname = endofname; res = arith(exp_str ? exp_str : arg, &errcode, &hooks); free(exp_str); if (errcode < 0) { const char *msg = "error in arithmetic"; switch (errcode) { case -3: msg = "exponent less than 0"; break; case -2: msg = "divide by 0"; break; case -5: msg = "expression recursion loop detected"; break; } die_if_script(msg); } debug_printf_subst("ARITH RES '"arith_t_fmt"'\n", res); sprintf(arith_buf, arith_t_fmt, res); val = arith_buf; break; } #endif default: /* varname */ case_default: { bool exp_len = false; bool exp_null = false; char *var = arg; char exp_save = exp_save; /* for compiler */ char exp_op = exp_op; /* for compiler */ char *exp_word = exp_word; /* for compiler */ size_t exp_off = 0; *p = '\0'; arg[0] = first_ch & 0x7f; /* prepare for expansions */ if (var[0] == '#') { /* handle length expansion ${#var} */ exp_len = true; ++var; } else { /* maybe handle parameter expansion */ exp_off = strcspn(var, ":-=+?%#"); if (!var[exp_off]) exp_off = 0; if (exp_off) { exp_save = var[exp_off]; exp_null = exp_save == ':'; exp_word = var + exp_off; if (exp_null) ++exp_word; exp_op = *exp_word++; var[exp_off] = '\0'; } } /* lookup the variable in question */ if (isdigit(var[0])) { /* handle_dollar() should have vetted var for us */ i = xatoi_u(var); if (i < G.global_argc) val = G.global_argv[i]; /* else val remains NULL: $N with too big N */ } else val = get_local_var_value(var); /* handle any expansions */ if (exp_len) { debug_printf_expand("expand: length of '%s' = ", val); val = utoa(val ? strlen(val) : 0); debug_printf_expand("%s\n", val); } else if (exp_off) { if (exp_op == '%' || exp_op == '#') { if (val) { /* we need to do a pattern match */ bool match_at_left; char *loc; scan_t scan = pick_scan(exp_op, *exp_word, &match_at_left); if (exp_op == *exp_word) /* ## or %% */ ++exp_word; val = dyn_val = xstrdup(val); loc = scan(dyn_val, exp_word, match_at_left); if (match_at_left) /* # or ## */ val = loc; else if (loc) /* % or %% and match was found */ *loc = '\0'; } } else { /* we need to do an expansion */ int exp_test = (!val || (exp_null && !val[0])); if (exp_op == '+') exp_test = !exp_test; debug_printf_expand("expand: op:%c (null:%s) test:%i\n", exp_op, exp_null ? "true" : "false", exp_test); if (exp_test) { if (exp_op == '?') { //TODO: how interactive bash aborts expansion mid-command? /* ${var?[error_msg_if_unset]} */ /* ${var:?[error_msg_if_unset_or_null]} */ /* mimic bash message */ die_if_script("%s: %s", var, exp_word[0] ? exp_word : "parameter null or not set" ); } else { val = exp_word; } if (exp_op == '=') { /* ${var=[word]} or ${var:=[word]} */ if (isdigit(var[0]) || var[0] == '#') { /* mimic bash message */ die_if_script("$%s: cannot assign in this way", var); val = NULL; } else { char *new_var = xasprintf("%s=%s", var, val); set_local_var(new_var, /*exp:*/ 0, /*lvl:*/ 0, /*ro:*/ 0); } } } } var[exp_off] = exp_save; } arg[0] = first_ch; #if ENABLE_HUSH_TICK store_val: #endif if (!(first_ch & 0x80)) { /* unquoted $VAR */ debug_printf_expand("unquoted '%s', output->o_escape:%d\n", val, output->o_escape); if (val) { /* unquoted var's contents should be globbed, so don't escape */ smallint sv = output->o_escape; output->o_escape = 0; n = expand_on_ifs(output, n, val); val = NULL; output->o_escape = sv; } } else { /* quoted $VAR, val will be appended below */ debug_printf_expand("quoted '%s', output->o_escape:%d\n", val, output->o_escape); } } /* default: */ } /* switch (char after ) */ if (val) { o_addQstr(output, val, strlen(val)); } free(dyn_val); /* Do the check to avoid writing to a const string */ if (*p != SPECIAL_VAR_SYMBOL) *p = SPECIAL_VAR_SYMBOL; #if ENABLE_HUSH_TICK o_free(&subst_result); #endif arg = ++p; } /* end of "while (SPECIAL_VAR_SYMBOL is found) ..." */ if (arg[0]) { debug_print_list("expand_vars_to_list[a]", output, n); /* this part is literal, and it was already pre-quoted * if needed (much earlier), do not use o_addQstr here! */ o_addstr_with_NUL(output, arg); debug_print_list("expand_vars_to_list[b]", output, n); } else if (output->length == o_get_last_ptr(output, n) /* expansion is empty */ && !(ored_ch & 0x80) /* and all vars were not quoted. */ ) { n--; /* allow to reuse list[n] later without re-growth */ output->has_empty_slot = 1; } else { o_addchr(output, '\0'); } return n; } static char **expand_variables(char **argv, int or_mask) { int n; char **list; char **v; o_string output = NULL_O_STRING; if (or_mask & 0x100) { output.o_escape = 1; /* protect against globbing for "$var" */ /* (unquoted $var will temporarily switch it off) */ output.o_glob = 1; } n = 0; v = argv; while (*v) { n = expand_vars_to_list(&output, n, *v, (unsigned char)or_mask); v++; } debug_print_list("expand_variables", &output, n); /* output.data (malloced in one block) gets returned in "list" */ list = o_finalize_list(&output, n); debug_print_strings("expand_variables[1]", list); return list; } static char **expand_strvec_to_strvec(char **argv) { return expand_variables(argv, 0x100); } #if ENABLE_HUSH_BASH_COMPAT static char **expand_strvec_to_strvec_singleword_noglob(char **argv) { return expand_variables(argv, 0x80); } #endif #ifdef CMD_SINGLEWORD_NOGLOB_COND static char **expand_strvec_to_strvec_singleword_noglob_cond(char **argv) { int n; char **list; char **v; o_string output = NULL_O_STRING; n = 0; v = argv; while (*v) { int is_var = is_well_formed_var_name(*v, '='); /* is_var * 0x80: singleword expansion for vars */ n = expand_vars_to_list(&output, n, *v, is_var * 0x80); /* Subtle! expand_vars_to_list did not glob last word yet. * It does this only when fed with further data. * Therefore we set globbing flags AFTER it, not before: */ /* if it is not recognizably abc=...; then: */ output.o_escape = !is_var; /* protect against globbing for "$var" */ /* (unquoted $var will temporarily switch it off) */ output.o_glob = !is_var; /* and indeed do globbing */ v++; } debug_print_list("expand_cond", &output, n); /* output.data (malloced in one block) gets returned in "list" */ list = o_finalize_list(&output, n); debug_print_strings("expand_cond[1]", list); return list; } #endif /* Used for expansion of right hand of assignments */ /* NB: should NOT do globbing! "export v=/bin/c*; env | grep ^v=" outputs * "v=/bin/c*" */ static char *expand_string_to_string(const char *str) { char *argv[2], **list; argv[0] = (char*)str; argv[1] = NULL; list = expand_variables(argv, 0x80); /* 0x80: singleword expansion */ if (HUSH_DEBUG) if (!list[0] || list[1]) bb_error_msg_and_die("BUG in varexp2"); /* actually, just move string 2*sizeof(char*) bytes back */ overlapping_strcpy((char*)list, list[0]); unbackslash((char*)list); debug_printf_expand("string_to_string='%s'\n", (char*)list); return (char*)list; } /* Used for "eval" builtin */ static char* expand_strvec_to_string(char **argv) { char **list; list = expand_variables(argv, 0x80); /* Convert all NULs to spaces */ if (list[0]) { int n = 1; while (list[n]) { if (HUSH_DEBUG) if (list[n-1] + strlen(list[n-1]) + 1 != list[n]) bb_error_msg_and_die("BUG in varexp3"); /* bash uses ' ' regardless of $IFS contents */ list[n][-1] = ' '; n++; } } overlapping_strcpy((char*)list, list[0]); debug_printf_expand("strvec_to_string='%s'\n", (char*)list); return (char*)list; } static char **expand_assignments(char **argv, int count) { int i; char **p = NULL; /* Expand assignments into one string each */ for (i = 0; i < count; i++) { p = add_string_to_strings(p, expand_string_to_string(argv[i])); } return p; } #if BB_MMU /* never called */ void re_execute_shell(char ***to_free, const char *s, char *g_argv0, char **g_argv, char **builtin_argv) NORETURN; static void reset_traps_to_defaults(void) { /* This function is always called in a child shell * after fork (not vfork, NOMMU doesn't use this function). */ unsigned sig; unsigned mask; /* Child shells are not interactive. * SIGTTIN/SIGTTOU/SIGTSTP should not have special handling. * Testcase: (while :; do :; done) + ^Z should background. * Same goes for SIGTERM, SIGHUP, SIGINT. */ if (!G.traps && !(G.non_DFL_mask & SPECIAL_INTERACTIVE_SIGS)) return; /* already no traps and no SPECIAL_INTERACTIVE_SIGS */ /* Switching off SPECIAL_INTERACTIVE_SIGS. * Stupid. It can be done with *single* &= op, but we can't use * the fact that G.blocked_set is implemented as a bitmask * in libc... */ mask = (SPECIAL_INTERACTIVE_SIGS >> 1); sig = 1; while (1) { if (mask & 1) { /* Careful. Only if no trap or trap is not "" */ if (!G.traps || !G.traps[sig] || G.traps[sig][0]) sigdelset(&G.blocked_set, sig); } mask >>= 1; if (!mask) break; sig++; } /* Our homegrown sig mask is saner to work with :) */ G.non_DFL_mask &= ~SPECIAL_INTERACTIVE_SIGS; /* Resetting all traps to default except empty ones */ mask = G.non_DFL_mask; if (G.traps) for (sig = 0; sig < NSIG; sig++, mask >>= 1) { if (!G.traps[sig] || !G.traps[sig][0]) continue; free(G.traps[sig]); G.traps[sig] = NULL; /* There is no signal for 0 (EXIT) */ if (sig == 0) continue; /* There was a trap handler, we just removed it. * But if sig still has non-DFL handling, * we should not unblock the sig. */ if (mask & 1) continue; sigdelset(&G.blocked_set, sig); } sigprocmask(SIG_SETMASK, &G.blocked_set, NULL); } #else /* !BB_MMU */ static void re_execute_shell(char ***to_free, const char *s, char *g_argv0, char **g_argv, char **builtin_argv) NORETURN; static void re_execute_shell(char ***to_free, const char *s, char *g_argv0, char **g_argv, char **builtin_argv) { #define NOMMU_HACK_FMT ("-$%x:%x:%x:%x:%x:%llx" IF_HUSH_LOOPS(":%x")) /* delims + 2 * (number of bytes in printed hex numbers) */ char param_buf[sizeof(NOMMU_HACK_FMT) + 2 * (sizeof(int)*6 + sizeof(long long)*1)]; char *heredoc_argv[4]; struct variable *cur; # if ENABLE_HUSH_FUNCTIONS struct function *funcp; # endif char **argv, **pp; unsigned cnt; unsigned long long empty_trap_mask; if (!g_argv0) { /* heredoc */ argv = heredoc_argv; argv[0] = (char *) G.argv0_for_re_execing; argv[1] = (char *) "-<"; argv[2] = (char *) s; argv[3] = NULL; pp = &argv[3]; /* used as pointer to empty environment */ goto do_exec; } cnt = 0; pp = builtin_argv; if (pp) while (*pp++) cnt++; empty_trap_mask = 0; if (G.traps) { int sig; for (sig = 1; sig < NSIG; sig++) { if (G.traps[sig] && !G.traps[sig][0]) empty_trap_mask |= 1LL << sig; } } sprintf(param_buf, NOMMU_HACK_FMT , (unsigned) G.root_pid , (unsigned) G.root_ppid , (unsigned) G.last_bg_pid , (unsigned) G.last_exitcode , cnt , empty_trap_mask IF_HUSH_LOOPS(, G.depth_of_loop) ); #undef NOMMU_HACK_FMT /* 1:hush 2:-$::: * 3:-c 4: 5: 6:NULL */ cnt += 6; for (cur = G.top_var; cur; cur = cur->next) { if (!cur->flg_export || cur->flg_read_only) cnt += 2; } # if ENABLE_HUSH_FUNCTIONS for (funcp = G.top_func; funcp; funcp = funcp->next) cnt += 3; # endif pp = g_argv; while (*pp++) cnt++; *to_free = argv = pp = xzalloc(sizeof(argv[0]) * cnt); *pp++ = (char *) G.argv0_for_re_execing; *pp++ = param_buf; for (cur = G.top_var; cur; cur = cur->next) { if (cur->varstr == hush_version_str) continue; if (cur->flg_read_only) { *pp++ = (char *) "-R"; *pp++ = cur->varstr; } else if (!cur->flg_export) { *pp++ = (char *) "-V"; *pp++ = cur->varstr; } } # if ENABLE_HUSH_FUNCTIONS for (funcp = G.top_func; funcp; funcp = funcp->next) { *pp++ = (char *) "-F"; *pp++ = funcp->name; *pp++ = funcp->body_as_string; } # endif /* We can pass activated traps here. Say, -Tnn:trap_string * * However, POSIX says that subshells reset signals with traps * to SIG_DFL. * I tested bash-3.2 and it not only does that with true subshells * of the form ( list ), but with any forked children shells. * I set trap "echo W" WINCH; and then tried: * * { echo 1; sleep 20; echo 2; } & * while true; do echo 1; sleep 20; echo 2; break; done & * true | { echo 1; sleep 20; echo 2; } | cat * * In all these cases sending SIGWINCH to the child shell * did not run the trap. If I add trap "echo V" WINCH; * _inside_ group (just before echo 1), it works. * * I conclude it means we don't need to pass active traps here. * Even if we would use signal handlers instead of signal masking * in order to implement trap handling, * exec syscall below resets signals to SIG_DFL for us. */ *pp++ = (char *) "-c"; *pp++ = (char *) s; if (builtin_argv) { while (*++builtin_argv) *pp++ = *builtin_argv; *pp++ = (char *) ""; } *pp++ = g_argv0; while (*g_argv) *pp++ = *g_argv++; /* *pp = NULL; - is already there */ pp = environ; do_exec: debug_printf_exec("re_execute_shell pid:%d cmd:'%s'\n", getpid(), s); sigprocmask(SIG_SETMASK, &G.inherited_set, NULL); execve(bb_busybox_exec_path, argv, pp); /* Fallback. Useful for init=/bin/hush usage etc */ if (argv[0][0] == '/') execve(argv[0], argv, pp); xfunc_error_retval = 127; bb_error_msg_and_die("can't re-execute the shell"); } #endif /* !BB_MMU */ static void setup_heredoc(struct redir_struct *redir) { struct fd_pair pair; pid_t pid; int len, written; /* the _body_ of heredoc (misleading field name) */ const char *heredoc = redir->rd_filename; char *expanded; #if !BB_MMU char **to_free; #endif expanded = NULL; if (!(redir->rd_dup & HEREDOC_QUOTED)) { expanded = expand_pseudo_dquoted(heredoc); if (expanded) heredoc = expanded; } len = strlen(heredoc); close(redir->rd_fd); /* often saves dup2+close in xmove_fd */ xpiped_pair(pair); xmove_fd(pair.rd, redir->rd_fd); /* Try writing without forking. Newer kernels have * dynamically growing pipes. Must use non-blocking write! */ ndelay_on(pair.wr); while (1) { written = write(pair.wr, heredoc, len); if (written <= 0) break; len -= written; if (len == 0) { close(pair.wr); free(expanded); return; } heredoc += written; } ndelay_off(pair.wr); /* Okay, pipe buffer was not big enough */ /* Note: we must not create a stray child (bastard? :) * for the unsuspecting parent process. Child creates a grandchild * and exits before parent execs the process which consumes heredoc * (that exec happens after we return from this function) */ #if !BB_MMU to_free = NULL; #endif pid = vfork(); if (pid < 0) bb_perror_msg_and_die("vfork"); if (pid == 0) { /* child */ disable_restore_tty_pgrp_on_exit(); pid = BB_MMU ? fork() : vfork(); if (pid < 0) bb_perror_msg_and_die(BB_MMU ? "fork" : "vfork"); if (pid != 0) _exit(0); /* grandchild */ close(redir->rd_fd); /* read side of the pipe */ #if BB_MMU full_write(pair.wr, heredoc, len); /* may loop or block */ _exit(0); #else /* Delegate blocking writes to another process */ xmove_fd(pair.wr, STDOUT_FILENO); re_execute_shell(&to_free, heredoc, NULL, NULL, NULL); #endif } /* parent */ #if ENABLE_HUSH_FAST G.count_SIGCHLD++; //bb_error_msg("[%d] fork in setup_heredoc: G.count_SIGCHLD:%d G.handled_SIGCHLD:%d", getpid(), G.count_SIGCHLD, G.handled_SIGCHLD); #endif enable_restore_tty_pgrp_on_exit(); #if !BB_MMU free(to_free); #endif close(pair.wr); free(expanded); wait(NULL); /* wait till child has died */ } /* squirrel != NULL means we squirrel away copies of stdin, stdout, * and stderr if they are redirected. */ static int setup_redirects(struct command *prog, int squirrel[]) { int openfd, mode; struct redir_struct *redir; for (redir = prog->redirects; redir; redir = redir->next) { if (redir->rd_type == REDIRECT_HEREDOC2) { /* rd_fd<rd_fd < 3 && squirrel[redir->rd_fd] < 0 ) { squirrel[redir->rd_fd] = dup(redir->rd_fd); } /* for REDIRECT_HEREDOC2, rd_filename holds _contents_ * of the heredoc */ debug_printf_parse("set heredoc '%s'\n", redir->rd_filename); setup_heredoc(redir); continue; } if (redir->rd_dup == REDIRFD_TO_FILE) { /* rd_fd<*>file case (<*> is <,>,>>,<>) */ char *p; if (redir->rd_filename == NULL) { /* Something went wrong in the parse. * Pretend it didn't happen */ bb_error_msg("bug in redirect parse"); continue; } mode = redir_table[redir->rd_type].mode; p = expand_string_to_string(redir->rd_filename); openfd = open_or_warn(p, mode); free(p); if (openfd < 0) { /* this could get lost if stderr has been redirected, but * bash and ash both lose it as well (though zsh doesn't!) */ //what the above comment tries to say? return 1; } } else { /* rd_fd<*>rd_dup or rd_fd<*>- cases */ openfd = redir->rd_dup; } if (openfd != redir->rd_fd) { if (squirrel && redir->rd_fd < 3 && squirrel[redir->rd_fd] < 0 ) { squirrel[redir->rd_fd] = dup(redir->rd_fd); } if (openfd == REDIRFD_CLOSE) { /* "n>-" means "close me" */ close(redir->rd_fd); } else { xdup2(openfd, redir->rd_fd); if (redir->rd_dup == REDIRFD_TO_FILE) close(openfd); } } } return 0; } static void restore_redirects(int squirrel[]) { int i, fd; for (i = 0; i < 3; i++) { fd = squirrel[i]; if (fd != -1) { /* We simply die on error */ xmove_fd(fd, i); } } } static void free_pipe_list(struct pipe *head); /* Return code is the exit status of the pipe */ static void free_pipe(struct pipe *pi) { char **p; struct command *command; struct redir_struct *r, *rnext; int a, i; if (pi->stopped_cmds > 0) /* why? */ return; debug_printf_clean("run pipe: (pid %d)\n", getpid()); for (i = 0; i < pi->num_cmds; i++) { command = &pi->cmds[i]; debug_printf_clean(" command %d:\n", i); if (command->argv) { for (a = 0, p = command->argv; *p; a++, p++) { debug_printf_clean(" argv[%d] = %s\n", a, *p); } free_strings(command->argv); command->argv = NULL; } /* not "else if": on syntax error, we may have both! */ if (command->group) { debug_printf_clean(" begin group (cmd_type:%d)\n", command->cmd_type); free_pipe_list(command->group); debug_printf_clean(" end group\n"); command->group = NULL; } /* else is crucial here. * If group != NULL, child_func is meaningless */ #if ENABLE_HUSH_FUNCTIONS else if (command->child_func) { debug_printf_exec("cmd %p releases child func at %p\n", command, command->child_func); command->child_func->parent_cmd = NULL; } #endif #if !BB_MMU free(command->group_as_string); command->group_as_string = NULL; #endif for (r = command->redirects; r; r = rnext) { debug_printf_clean(" redirect %d%s", r->rd_fd, redir_table[r->rd_type].descrip); /* guard against the case >$FOO, where foo is unset or blank */ if (r->rd_filename) { debug_printf_clean(" fname:'%s'\n", r->rd_filename); free(r->rd_filename); r->rd_filename = NULL; } debug_printf_clean(" rd_dup:%d\n", r->rd_dup); rnext = r->next; free(r); } command->redirects = NULL; } free(pi->cmds); /* children are an array, they get freed all at once */ pi->cmds = NULL; #if ENABLE_HUSH_JOB free(pi->cmdtext); pi->cmdtext = NULL; #endif } static void free_pipe_list(struct pipe *head) { struct pipe *pi, *next; for (pi = head; pi; pi = next) { #if HAS_KEYWORDS debug_printf_clean(" pipe reserved word %d\n", pi->res_word); #endif free_pipe(pi); debug_printf_clean("pipe followup code %d\n", pi->followup); next = pi->next; /*pi->next = NULL;*/ free(pi); } } static int run_list(struct pipe *pi); #if BB_MMU #define parse_stream(pstring, input, end_trigger) \ parse_stream(input, end_trigger) #endif static struct pipe *parse_stream(char **pstring, struct in_str *input, int end_trigger); static void parse_and_run_string(const char *s); static char *find_in_path(const char *arg) { char *ret = NULL; const char *PATH = get_local_var_value("PATH"); if (!PATH) return NULL; while (1) { const char *end = strchrnul(PATH, ':'); int sz = end - PATH; /* must be int! */ free(ret); if (sz != 0) { ret = xasprintf("%.*s/%s", sz, PATH, arg); } else { /* We have xxx::yyyy in $PATH, * it means "use current dir" */ ret = xstrdup(arg); } if (access(ret, F_OK) == 0) break; if (*end == '\0') { free(ret); return NULL; } PATH = end + 1; } return ret; } static const struct built_in_command* find_builtin_helper(const char *name, const struct built_in_command *x, const struct built_in_command *end) { while (x != end) { if (strcmp(name, x->b_cmd) != 0) { x++; continue; } debug_printf_exec("found builtin '%s'\n", name); return x; } return NULL; } static const struct built_in_command* find_builtin1(const char *name) { return find_builtin_helper(name, bltins1, &bltins1[ARRAY_SIZE(bltins1)]); } static const struct built_in_command* find_builtin(const char *name) { const struct built_in_command *x = find_builtin1(name); if (x) return x; return find_builtin_helper(name, bltins2, &bltins2[ARRAY_SIZE(bltins2)]); } #if ENABLE_HUSH_FUNCTIONS static struct function **find_function_slot(const char *name) { struct function **funcpp = &G.top_func; while (*funcpp) { if (strcmp(name, (*funcpp)->name) == 0) { break; } funcpp = &(*funcpp)->next; } return funcpp; } static const struct function *find_function(const char *name) { const struct function *funcp = *find_function_slot(name); if (funcp) debug_printf_exec("found function '%s'\n", name); return funcp; } /* Note: takes ownership on name ptr */ static struct function *new_function(char *name) { struct function **funcpp = find_function_slot(name); struct function *funcp = *funcpp; if (funcp != NULL) { struct command *cmd = funcp->parent_cmd; debug_printf_exec("func %p parent_cmd %p\n", funcp, cmd); if (!cmd) { debug_printf_exec("freeing & replacing function '%s'\n", funcp->name); free(funcp->name); /* Note: if !funcp->body, do not free body_as_string! * This is a special case of "-F name body" function: * body_as_string was not malloced! */ if (funcp->body) { free_pipe_list(funcp->body); # if !BB_MMU free(funcp->body_as_string); # endif } } else { debug_printf_exec("reinserting in tree & replacing function '%s'\n", funcp->name); cmd->argv[0] = funcp->name; cmd->group = funcp->body; # if !BB_MMU cmd->group_as_string = funcp->body_as_string; # endif } } else { debug_printf_exec("remembering new function '%s'\n", name); funcp = *funcpp = xzalloc(sizeof(*funcp)); /*funcp->next = NULL;*/ } funcp->name = name; return funcp; } static void unset_func(const char *name) { struct function **funcpp = find_function_slot(name); struct function *funcp = *funcpp; if (funcp != NULL) { debug_printf_exec("freeing function '%s'\n", funcp->name); *funcpp = funcp->next; /* funcp is unlinked now, deleting it. * Note: if !funcp->body, the function was created by * "-F name body", do not free ->body_as_string * and ->name as they were not malloced. */ if (funcp->body) { free_pipe_list(funcp->body); free(funcp->name); # if !BB_MMU free(funcp->body_as_string); # endif } free(funcp); } } # if BB_MMU #define exec_function(to_free, funcp, argv) \ exec_function(funcp, argv) # endif static void exec_function(char ***to_free, const struct function *funcp, char **argv) NORETURN; static void exec_function(char ***to_free, const struct function *funcp, char **argv) { # if BB_MMU int n = 1; argv[0] = G.global_argv[0]; G.global_argv = argv; while (*++argv) n++; G.global_argc = n; /* On MMU, funcp->body is always non-NULL */ n = run_list(funcp->body); fflush_all(); _exit(n); # else re_execute_shell(to_free, funcp->body_as_string, G.global_argv[0], argv + 1, NULL); # endif } static int run_function(const struct function *funcp, char **argv) { int rc; save_arg_t sv; smallint sv_flg; save_and_replace_G_args(&sv, argv); /* "we are in function, ok to use return" */ sv_flg = G.flag_return_in_progress; G.flag_return_in_progress = -1; # if ENABLE_HUSH_LOCAL G.func_nest_level++; # endif /* On MMU, funcp->body is always non-NULL */ # if !BB_MMU if (!funcp->body) { /* Function defined by -F */ parse_and_run_string(funcp->body_as_string); rc = G.last_exitcode; } else # endif { rc = run_list(funcp->body); } # if ENABLE_HUSH_LOCAL { struct variable *var; struct variable **var_pp; var_pp = &G.top_var; while ((var = *var_pp) != NULL) { if (var->func_nest_level < G.func_nest_level) { var_pp = &var->next; continue; } /* Unexport */ if (var->flg_export) bb_unsetenv(var->varstr); /* Remove from global list */ *var_pp = var->next; /* Free */ if (!var->max_len) free(var->varstr); free(var); } G.func_nest_level--; } # endif G.flag_return_in_progress = sv_flg; restore_G_args(&sv, argv); return rc; } #endif /* ENABLE_HUSH_FUNCTIONS */ #if BB_MMU #define exec_builtin(to_free, x, argv) \ exec_builtin(x, argv) #else #define exec_builtin(to_free, x, argv) \ exec_builtin(to_free, argv) #endif static void exec_builtin(char ***to_free, const struct built_in_command *x, char **argv) NORETURN; static void exec_builtin(char ***to_free, const struct built_in_command *x, char **argv) { #if BB_MMU int rcode = x->b_function(argv); fflush_all(); _exit(rcode); #else /* On NOMMU, we must never block! * Example: { sleep 99 | read line; } & echo Ok */ re_execute_shell(to_free, argv[0], G.global_argv[0], G.global_argv + 1, argv); #endif } static void execvp_or_die(char **argv) NORETURN; static void execvp_or_die(char **argv) { debug_printf_exec("execing '%s'\n", argv[0]); sigprocmask(SIG_SETMASK, &G.inherited_set, NULL); execvp(argv[0], argv); bb_perror_msg("can't execute '%s'", argv[0]); _exit(127); /* bash compat */ } #if BB_MMU #define pseudo_exec_argv(nommu_save, argv, assignment_cnt, argv_expanded) \ pseudo_exec_argv(argv, assignment_cnt, argv_expanded) #define pseudo_exec(nommu_save, command, argv_expanded) \ pseudo_exec(command, argv_expanded) #endif /* Called after [v]fork() in run_pipe, or from builtin_exec. * Never returns. * Don't exit() here. If you don't exec, use _exit instead. * The at_exit handlers apparently confuse the calling process, * in particular stdin handling. Not sure why? -- because of vfork! (vda) */ static void pseudo_exec_argv(nommu_save_t *nommu_save, char **argv, int assignment_cnt, char **argv_expanded) NORETURN; static NOINLINE void pseudo_exec_argv(nommu_save_t *nommu_save, char **argv, int assignment_cnt, char **argv_expanded) { char **new_env; /* Case when we are here: ... | var=val | ... */ if (!argv[assignment_cnt]) _exit(EXIT_SUCCESS); new_env = expand_assignments(argv, assignment_cnt); #if BB_MMU set_vars_and_save_old(new_env); free(new_env); /* optional */ /* we can also destroy set_vars_and_save_old's return value, * to save memory */ #else nommu_save->new_env = new_env; nommu_save->old_vars = set_vars_and_save_old(new_env); #endif if (argv_expanded) { argv = argv_expanded; } else { argv = expand_strvec_to_strvec(argv + assignment_cnt); #if !BB_MMU nommu_save->argv = argv; #endif } #if ENABLE_FEATURE_SH_STANDALONE || BB_MMU if (strchr(argv[0], '/') != NULL) goto skip; #endif /* Check if the command matches any of the builtins. * Depending on context, this might be redundant. But it's * easier to waste a few CPU cycles than it is to figure out * if this is one of those cases. */ { /* On NOMMU, it is more expensive to re-execute shell * just in order to run echo or test builtin. * It's better to skip it here and run corresponding * non-builtin later. */ const struct built_in_command *x; x = BB_MMU ? find_builtin(argv[0]) : find_builtin1(argv[0]); if (x) { exec_builtin(&nommu_save->argv_from_re_execing, x, argv); } } #if ENABLE_HUSH_FUNCTIONS /* Check if the command matches any functions */ { const struct function *funcp = find_function(argv[0]); if (funcp) { exec_function(&nommu_save->argv_from_re_execing, funcp, argv); } } #endif #if ENABLE_FEATURE_SH_STANDALONE /* Check if the command matches any busybox applets */ { int a = find_applet_by_name(argv[0]); if (a >= 0) { # if BB_MMU /* see above why on NOMMU it is not allowed */ if (APPLET_IS_NOEXEC(a)) { debug_printf_exec("running applet '%s'\n", argv[0]); run_applet_no_and_exit(a, argv); } # endif /* Re-exec ourselves */ debug_printf_exec("re-execing applet '%s'\n", argv[0]); sigprocmask(SIG_SETMASK, &G.inherited_set, NULL); execv(bb_busybox_exec_path, argv); /* If they called chroot or otherwise made the binary no longer * executable, fall through */ } } #endif #if ENABLE_FEATURE_SH_STANDALONE || BB_MMU skip: #endif execvp_or_die(argv); } /* Called after [v]fork() in run_pipe */ static void pseudo_exec(nommu_save_t *nommu_save, struct command *command, char **argv_expanded) NORETURN; static void pseudo_exec(nommu_save_t *nommu_save, struct command *command, char **argv_expanded) { if (command->argv) { pseudo_exec_argv(nommu_save, command->argv, command->assignment_cnt, argv_expanded); } if (command->group) { /* Cases when we are here: * ( list ) * { list } & * ... | ( list ) | ... * ... | { list } | ... */ #if BB_MMU int rcode; debug_printf_exec("pseudo_exec: run_list\n"); reset_traps_to_defaults(); rcode = run_list(command->group); /* OK to leak memory by not calling free_pipe_list, * since this process is about to exit */ _exit(rcode); #else re_execute_shell(&nommu_save->argv_from_re_execing, command->group_as_string, G.global_argv[0], G.global_argv + 1, NULL); #endif } /* Case when we are here: ... | >file */ debug_printf_exec("pseudo_exec'ed null command\n"); _exit(EXIT_SUCCESS); } #if ENABLE_HUSH_JOB static const char *get_cmdtext(struct pipe *pi) { char **argv; char *p; int len; /* This is subtle. ->cmdtext is created only on first backgrounding. * (Think "cat, , fg, , fg, ...." here...) * On subsequent bg argv is trashed, but we won't use it */ if (pi->cmdtext) return pi->cmdtext; argv = pi->cmds[0].argv; if (!argv || !argv[0]) { pi->cmdtext = xzalloc(1); return pi->cmdtext; } len = 0; do { len += strlen(*argv) + 1; } while (*++argv); p = xmalloc(len); pi->cmdtext = p; argv = pi->cmds[0].argv; do { len = strlen(*argv); memcpy(p, *argv, len); p += len; *p++ = ' '; } while (*++argv); p[-1] = '\0'; return pi->cmdtext; } static void insert_bg_job(struct pipe *pi) { struct pipe *job, **jobp; int i; /* Linear search for the ID of the job to use */ pi->jobid = 1; for (job = G.job_list; job; job = job->next) if (job->jobid >= pi->jobid) pi->jobid = job->jobid + 1; /* Add job to the list of running jobs */ jobp = &G.job_list; while ((job = *jobp) != NULL) jobp = &job->next; job = *jobp = xmalloc(sizeof(*job)); *job = *pi; /* physical copy */ job->next = NULL; job->cmds = xzalloc(sizeof(pi->cmds[0]) * pi->num_cmds); /* Cannot copy entire pi->cmds[] vector! This causes double frees */ for (i = 0; i < pi->num_cmds; i++) { job->cmds[i].pid = pi->cmds[i].pid; /* all other fields are not used and stay zero */ } job->cmdtext = xstrdup(get_cmdtext(pi)); if (G_interactive_fd) printf("[%d] %d %s\n", job->jobid, job->cmds[0].pid, job->cmdtext); /* Last command's pid goes to $! */ G.last_bg_pid = job->cmds[job->num_cmds - 1].pid; G.last_jobid = job->jobid; } static void remove_bg_job(struct pipe *pi) { struct pipe *prev_pipe; if (pi == G.job_list) { G.job_list = pi->next; } else { prev_pipe = G.job_list; while (prev_pipe->next != pi) prev_pipe = prev_pipe->next; prev_pipe->next = pi->next; } if (G.job_list) G.last_jobid = G.job_list->jobid; else G.last_jobid = 0; } /* Remove a backgrounded job */ static void delete_finished_bg_job(struct pipe *pi) { remove_bg_job(pi); pi->stopped_cmds = 0; free_pipe(pi); free(pi); } #endif /* JOB */ /* Check to see if any processes have exited -- if they * have, figure out why and see if a job has completed */ static int checkjobs(struct pipe* fg_pipe) { int attributes; int status; #if ENABLE_HUSH_JOB struct pipe *pi; #endif pid_t childpid; int rcode = 0; debug_printf_jobs("checkjobs %p\n", fg_pipe); attributes = WUNTRACED; if (fg_pipe == NULL) attributes |= WNOHANG; errno = 0; #if ENABLE_HUSH_FAST if (G.handled_SIGCHLD == G.count_SIGCHLD) { //bb_error_msg("[%d] checkjobs: G.count_SIGCHLD:%d G.handled_SIGCHLD:%d children?:%d fg_pipe:%p", //getpid(), G.count_SIGCHLD, G.handled_SIGCHLD, G.we_have_children, fg_pipe); /* There was neither fork nor SIGCHLD since last waitpid */ /* Avoid doing waitpid syscall if possible */ if (!G.we_have_children) { errno = ECHILD; return -1; } if (fg_pipe == NULL) { /* is WNOHANG set? */ /* We have children, but they did not exit * or stop yet (we saw no SIGCHLD) */ return 0; } /* else: !WNOHANG, waitpid will block, can't short-circuit */ } #endif /* Do we do this right? * bash-3.00# sleep 20 | false * * [3]+ Stopped sleep 20 | false * bash-3.00# echo $? * 1 <========== bg pipe is not fully done, but exitcode is already known! * [hush 1.14.0: yes we do it right] */ wait_more: while (1) { int i; int dead; #if ENABLE_HUSH_FAST i = G.count_SIGCHLD; #endif childpid = waitpid(-1, &status, attributes); if (childpid <= 0) { if (childpid && errno != ECHILD) bb_perror_msg("waitpid"); #if ENABLE_HUSH_FAST else { /* Until next SIGCHLD, waitpid's are useless */ G.we_have_children = (childpid == 0); G.handled_SIGCHLD = i; //bb_error_msg("[%d] checkjobs: waitpid returned <= 0, G.count_SIGCHLD:%d G.handled_SIGCHLD:%d", getpid(), G.count_SIGCHLD, G.handled_SIGCHLD); } #endif break; } dead = WIFEXITED(status) || WIFSIGNALED(status); #if DEBUG_JOBS if (WIFSTOPPED(status)) debug_printf_jobs("pid %d stopped by sig %d (exitcode %d)\n", childpid, WSTOPSIG(status), WEXITSTATUS(status)); if (WIFSIGNALED(status)) debug_printf_jobs("pid %d killed by sig %d (exitcode %d)\n", childpid, WTERMSIG(status), WEXITSTATUS(status)); if (WIFEXITED(status)) debug_printf_jobs("pid %d exited, exitcode %d\n", childpid, WEXITSTATUS(status)); #endif /* Were we asked to wait for fg pipe? */ if (fg_pipe) { for (i = 0; i < fg_pipe->num_cmds; i++) { debug_printf_jobs("check pid %d\n", fg_pipe->cmds[i].pid); if (fg_pipe->cmds[i].pid != childpid) continue; if (dead) { fg_pipe->cmds[i].pid = 0; fg_pipe->alive_cmds--; if (i == fg_pipe->num_cmds - 1) { /* last process gives overall exitstatus */ rcode = WEXITSTATUS(status); /* bash prints killer signal's name for *last* * process in pipe (prints just newline for SIGINT). * Mimic this. Example: "sleep 5" + (^\ or kill -QUIT) */ if (WIFSIGNALED(status)) { int sig = WTERMSIG(status); printf("%s\n", sig == SIGINT ? "" : get_signame(sig)); /* TODO: MIPS has 128 sigs (1..128), what if sig==128 here? * Maybe we need to use sig | 128? */ rcode = sig + 128; } IF_HAS_KEYWORDS(if (fg_pipe->pi_inverted) rcode = !rcode;) } } else { fg_pipe->cmds[i].is_stopped = 1; fg_pipe->stopped_cmds++; } debug_printf_jobs("fg_pipe: alive_cmds %d stopped_cmds %d\n", fg_pipe->alive_cmds, fg_pipe->stopped_cmds); if (fg_pipe->alive_cmds - fg_pipe->stopped_cmds <= 0) { /* All processes in fg pipe have exited or stopped */ /* Note: *non-interactive* bash does not continue if all processes in fg pipe * are stopped. Testcase: "cat | cat" in a script (not on command line!) * and "killall -STOP cat" */ if (G_interactive_fd) { #if ENABLE_HUSH_JOB if (fg_pipe->alive_cmds) insert_bg_job(fg_pipe); #endif return rcode; } if (!fg_pipe->alive_cmds) return rcode; } /* There are still running processes in the fg pipe */ goto wait_more; /* do waitpid again */ } /* it wasnt fg_pipe, look for process in bg pipes */ } #if ENABLE_HUSH_JOB /* We asked to wait for bg or orphaned children */ /* No need to remember exitcode in this case */ for (pi = G.job_list; pi; pi = pi->next) { for (i = 0; i < pi->num_cmds; i++) { if (pi->cmds[i].pid == childpid) goto found_pi_and_prognum; } } /* Happens when shell is used as init process (init=/bin/sh) */ debug_printf("checkjobs: pid %d was not in our list!\n", childpid); continue; /* do waitpid again */ found_pi_and_prognum: if (dead) { /* child exited */ pi->cmds[i].pid = 0; pi->alive_cmds--; if (!pi->alive_cmds) { if (G_interactive_fd) printf(JOB_STATUS_FORMAT, pi->jobid, "Done", pi->cmdtext); delete_finished_bg_job(pi); } } else { /* child stopped */ pi->cmds[i].is_stopped = 1; pi->stopped_cmds++; } #endif } /* while (waitpid succeeds)... */ return rcode; } #if ENABLE_HUSH_JOB static int checkjobs_and_fg_shell(struct pipe* fg_pipe) { pid_t p; int rcode = checkjobs(fg_pipe); if (G_saved_tty_pgrp) { /* Job finished, move the shell to the foreground */ p = getpgrp(); /* our process group id */ debug_printf_jobs("fg'ing ourself: getpgrp()=%d\n", (int)p); tcsetpgrp(G_interactive_fd, p); } return rcode; } #endif /* Start all the jobs, but don't wait for anything to finish. * See checkjobs(). * * Return code is normally -1, when the caller has to wait for children * to finish to determine the exit status of the pipe. If the pipe * is a simple builtin command, however, the action is done by the * time run_pipe returns, and the exit code is provided as the * return value. * * Returns -1 only if started some children. IOW: we have to * mask out retvals of builtins etc with 0xff! * * The only case when we do not need to [v]fork is when the pipe * is single, non-backgrounded, non-subshell command. Examples: * cmd ; ... { list } ; ... * cmd && ... { list } && ... * cmd || ... { list } || ... * If it is, then we can run cmd as a builtin, NOFORK [do we do this?], * or (if SH_STANDALONE) an applet, and we can run the { list } * with run_list. If it isn't one of these, we fork and exec cmd. * * Cases when we must fork: * non-single: cmd | cmd * backgrounded: cmd & { list } & * subshell: ( list ) [&] */ static NOINLINE int run_pipe(struct pipe *pi) { static const char *const null_ptr = NULL; int i; int nextin; struct command *command; char **argv_expanded; char **argv; char *p; /* it is not always needed, but we aim to smaller code */ int squirrel[] = { -1, -1, -1 }; int rcode; debug_printf_exec("run_pipe start: members:%d\n", pi->num_cmds); debug_enter(); IF_HUSH_JOB(pi->pgrp = -1;) pi->stopped_cmds = 0; command = &(pi->cmds[0]); argv_expanded = NULL; if (pi->num_cmds != 1 || pi->followup == PIPE_BG || command->cmd_type == CMD_SUBSHELL ) { goto must_fork; } pi->alive_cmds = 1; debug_printf_exec(": group:%p argv:'%s'\n", command->group, command->argv ? command->argv[0] : "NONE"); if (command->group) { #if ENABLE_HUSH_FUNCTIONS if (command->cmd_type == CMD_FUNCDEF) { /* "executing" func () { list } */ struct function *funcp; funcp = new_function(command->argv[0]); /* funcp->name is already set to argv[0] */ funcp->body = command->group; # if !BB_MMU funcp->body_as_string = command->group_as_string; command->group_as_string = NULL; # endif command->group = NULL; command->argv[0] = NULL; debug_printf_exec("cmd %p has child func at %p\n", command, funcp); funcp->parent_cmd = command; command->child_func = funcp; debug_printf_exec("run_pipe: return EXIT_SUCCESS\n"); debug_leave(); return EXIT_SUCCESS; } #endif /* { list } */ debug_printf("non-subshell group\n"); rcode = 1; /* exitcode if redir failed */ if (setup_redirects(command, squirrel) == 0) { debug_printf_exec(": run_list\n"); rcode = run_list(command->group) & 0xff; } restore_redirects(squirrel); IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;) debug_leave(); debug_printf_exec("run_pipe: return %d\n", rcode); return rcode; } argv = command->argv ? command->argv : (char **) &null_ptr; { const struct built_in_command *x; #if ENABLE_HUSH_FUNCTIONS const struct function *funcp; #else enum { funcp = 0 }; #endif char **new_env = NULL; struct variable *old_vars = NULL; if (argv[command->assignment_cnt] == NULL) { /* Assignments, but no command */ /* Ensure redirects take effect. Try "a=t >file" */ rcode = setup_redirects(command, squirrel); //FIXME: "false; q=`false`; echo $?" should print 1 restore_redirects(squirrel); /* Set shell variables */ while (*argv) { p = expand_string_to_string(*argv); debug_printf_exec("set shell var:'%s'->'%s'\n", *argv, p); set_local_var(p, /*exp:*/ 0, /*lvl:*/ 0, /*ro:*/ 0); argv++; } /* Do we need to flag set_local_var() errors? * "assignment to readonly var" and "putenv error" */ IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;) debug_leave(); debug_printf_exec("run_pipe: return %d\n", rcode); return rcode; } /* Expand the rest into (possibly) many strings each */ if (0) {} #if ENABLE_HUSH_BASH_COMPAT else if (command->cmd_type == CMD_SINGLEWORD_NOGLOB) { argv_expanded = expand_strvec_to_strvec_singleword_noglob(argv + command->assignment_cnt); } #endif #ifdef CMD_SINGLEWORD_NOGLOB_COND else if (command->cmd_type == CMD_SINGLEWORD_NOGLOB_COND) { argv_expanded = expand_strvec_to_strvec_singleword_noglob_cond(argv + command->assignment_cnt); } #endif else { argv_expanded = expand_strvec_to_strvec(argv + command->assignment_cnt); } /* if someone gives us an empty string: `cmd with empty output` */ if (!argv_expanded[0]) { free(argv_expanded); debug_leave(); return G.last_exitcode; } x = find_builtin(argv_expanded[0]); #if ENABLE_HUSH_FUNCTIONS funcp = NULL; if (!x) funcp = find_function(argv_expanded[0]); #endif if (x || funcp) { if (!funcp) { if (x->b_function == builtin_exec && argv_expanded[1] == NULL) { debug_printf("exec with redirects only\n"); rcode = setup_redirects(command, NULL); goto clean_up_and_ret1; } } /* setup_redirects acts on file descriptors, not FILEs. * This is perfect for work that comes after exec(). * Is it really safe for inline use? Experimentally, * things seem to work. */ rcode = setup_redirects(command, squirrel); if (rcode == 0) { new_env = expand_assignments(argv, command->assignment_cnt); old_vars = set_vars_and_save_old(new_env); if (!funcp) { debug_printf_exec(": builtin '%s' '%s'...\n", x->cmd, argv_expanded[1]); rcode = x->b_function(argv_expanded) & 0xff; fflush_all(); } #if ENABLE_HUSH_FUNCTIONS else { # if ENABLE_HUSH_LOCAL struct variable **sv; sv = G.shadowed_vars_pp; G.shadowed_vars_pp = &old_vars; # endif debug_printf_exec(": function '%s' '%s'...\n", funcp->name, argv_expanded[1]); rcode = run_function(funcp, argv_expanded) & 0xff; # if ENABLE_HUSH_LOCAL G.shadowed_vars_pp = sv; # endif } #endif } #if ENABLE_FEATURE_SH_STANDALONE clean_up_and_ret: #endif restore_redirects(squirrel); unset_vars(new_env); add_vars(old_vars); clean_up_and_ret1: free(argv_expanded); IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;) debug_leave(); debug_printf_exec("run_pipe return %d\n", rcode); return rcode; } #if ENABLE_FEATURE_SH_STANDALONE i = find_applet_by_name(argv_expanded[0]); if (i >= 0 && APPLET_IS_NOFORK(i)) { rcode = setup_redirects(command, squirrel); if (rcode == 0) { new_env = expand_assignments(argv, command->assignment_cnt); old_vars = set_vars_and_save_old(new_env); debug_printf_exec(": run_nofork_applet '%s' '%s'...\n", argv_expanded[0], argv_expanded[1]); rcode = run_nofork_applet(i, argv_expanded); } goto clean_up_and_ret; } #endif /* It is neither builtin nor applet. We must fork. */ } must_fork: /* NB: argv_expanded may already be created, and that * might include `cmd` runs! Do not rerun it! We *must* * use argv_expanded if it's non-NULL */ /* Going to fork a child per each pipe member */ pi->alive_cmds = 0; nextin = 0; for (i = 0; i < pi->num_cmds; i++) { struct fd_pair pipefds; #if !BB_MMU volatile nommu_save_t nommu_save; nommu_save.new_env = NULL; nommu_save.old_vars = NULL; nommu_save.argv = NULL; nommu_save.argv_from_re_execing = NULL; #endif command = &(pi->cmds[i]); if (command->argv) { debug_printf_exec(": pipe member '%s' '%s'...\n", command->argv[0], command->argv[1]); } else { debug_printf_exec(": pipe member with no argv\n"); } /* pipes are inserted between pairs of commands */ pipefds.rd = 0; pipefds.wr = 1; if ((i + 1) < pi->num_cmds) xpiped_pair(pipefds); command->pid = BB_MMU ? fork() : vfork(); if (!command->pid) { /* child */ #if ENABLE_HUSH_JOB disable_restore_tty_pgrp_on_exit(); CLEAR_RANDOM_T(&G.random_gen); /* or else $RANDOM repeats in child */ /* Every child adds itself to new process group * with pgid == pid_of_first_child_in_pipe */ if (G.run_list_level == 1 && G_interactive_fd) { pid_t pgrp; pgrp = pi->pgrp; if (pgrp < 0) /* true for 1st process only */ pgrp = getpid(); if (setpgid(0, pgrp) == 0 && pi->followup != PIPE_BG && G_saved_tty_pgrp /* we have ctty */ ) { /* We do it in *every* child, not just first, * to avoid races */ tcsetpgrp(G_interactive_fd, pgrp); } } #endif if (pi->alive_cmds == 0 && pi->followup == PIPE_BG) { /* 1st cmd in backgrounded pipe * should have its stdin /dev/null'ed */ close(0); if (open(bb_dev_null, O_RDONLY)) xopen("/", O_RDONLY); } else { xmove_fd(nextin, 0); } xmove_fd(pipefds.wr, 1); if (pipefds.rd > 1) close(pipefds.rd); /* Like bash, explicit redirects override pipes, * and the pipe fd is available for dup'ing. */ if (setup_redirects(command, NULL)) _exit(1); /* Restore default handlers just prior to exec */ /*signal(SIGCHLD, SIG_DFL); - so far we don't have any handlers */ /* Stores to nommu_save list of env vars putenv'ed * (NOMMU, on MMU we don't need that) */ /* cast away volatility... */ pseudo_exec((nommu_save_t*) &nommu_save, command, argv_expanded); /* pseudo_exec() does not return */ } /* parent or error */ #if ENABLE_HUSH_FAST G.count_SIGCHLD++; //bb_error_msg("[%d] fork in run_pipe: G.count_SIGCHLD:%d G.handled_SIGCHLD:%d", getpid(), G.count_SIGCHLD, G.handled_SIGCHLD); #endif enable_restore_tty_pgrp_on_exit(); #if !BB_MMU /* Clean up after vforked child */ free(nommu_save.argv); free(nommu_save.argv_from_re_execing); unset_vars(nommu_save.new_env); add_vars(nommu_save.old_vars); #endif free(argv_expanded); argv_expanded = NULL; if (command->pid < 0) { /* [v]fork failed */ /* Clearly indicate, was it fork or vfork */ bb_perror_msg(BB_MMU ? "fork" : "vfork"); } else { pi->alive_cmds++; #if ENABLE_HUSH_JOB /* Second and next children need to know pid of first one */ if (pi->pgrp < 0) pi->pgrp = command->pid; #endif } if (i) close(nextin); if ((i + 1) < pi->num_cmds) close(pipefds.wr); /* Pass read (output) pipe end to next iteration */ nextin = pipefds.rd; } if (!pi->alive_cmds) { debug_leave(); debug_printf_exec("run_pipe return 1 (all forks failed, no children)\n"); return 1; } debug_leave(); debug_printf_exec("run_pipe return -1 (%u children started)\n", pi->alive_cmds); return -1; } #ifndef debug_print_tree static void debug_print_tree(struct pipe *pi, int lvl) { static const char *const PIPE[] = { [PIPE_SEQ] = "SEQ", [PIPE_AND] = "AND", [PIPE_OR ] = "OR" , [PIPE_BG ] = "BG" , }; static const char *RES[] = { [RES_NONE ] = "NONE" , # if ENABLE_HUSH_IF [RES_IF ] = "IF" , [RES_THEN ] = "THEN" , [RES_ELIF ] = "ELIF" , [RES_ELSE ] = "ELSE" , [RES_FI ] = "FI" , # endif # if ENABLE_HUSH_LOOPS [RES_FOR ] = "FOR" , [RES_WHILE] = "WHILE", [RES_UNTIL] = "UNTIL", [RES_DO ] = "DO" , [RES_DONE ] = "DONE" , # endif # if ENABLE_HUSH_LOOPS || ENABLE_HUSH_CASE [RES_IN ] = "IN" , # endif # if ENABLE_HUSH_CASE [RES_CASE ] = "CASE" , [RES_CASE_IN ] = "CASE_IN" , [RES_MATCH] = "MATCH", [RES_CASE_BODY] = "CASE_BODY", [RES_ESAC ] = "ESAC" , # endif [RES_XXXX ] = "XXXX" , [RES_SNTX ] = "SNTX" , }; static const char *const CMDTYPE[] = { "{}", "()", "[noglob]", # if ENABLE_HUSH_FUNCTIONS "func()", # endif }; int pin, prn; pin = 0; while (pi) { fprintf(stderr, "%*spipe %d res_word=%s followup=%d %s\n", lvl*2, "", pin, RES[pi->res_word], pi->followup, PIPE[pi->followup]); prn = 0; while (prn < pi->num_cmds) { struct command *command = &pi->cmds[prn]; char **argv = command->argv; fprintf(stderr, "%*s cmd %d assignment_cnt:%d", lvl*2, "", prn, command->assignment_cnt); if (command->group) { fprintf(stderr, " group %s: (argv=%p)%s%s\n", CMDTYPE[command->cmd_type], argv #if !BB_MMU , " group_as_string:", command->group_as_string #else , "", "" #endif ); debug_print_tree(command->group, lvl+1); prn++; continue; } if (argv) while (*argv) { fprintf(stderr, " '%s'", *argv); argv++; } fprintf(stderr, "\n"); prn++; } pi = pi->next; pin++; } } #endif /* debug_print_tree */ /* NB: called by pseudo_exec, and therefore must not modify any * global data until exec/_exit (we can be a child after vfork!) */ static int run_list(struct pipe *pi) { #if ENABLE_HUSH_CASE char *case_word = NULL; #endif #if ENABLE_HUSH_LOOPS struct pipe *loop_top = NULL; char **for_lcur = NULL; char **for_list = NULL; #endif smallint last_followup; smalluint rcode; #if ENABLE_HUSH_IF || ENABLE_HUSH_CASE smalluint cond_code = 0; #else enum { cond_code = 0 }; #endif #if HAS_KEYWORDS smallint rword; /* enum reserved_style */ smallint last_rword; /* ditto */ #endif debug_printf_exec("run_list start lvl %d\n", G.run_list_level); debug_enter(); #if ENABLE_HUSH_LOOPS /* Check syntax for "for" */ for (struct pipe *cpipe = pi; cpipe; cpipe = cpipe->next) { if (cpipe->res_word != RES_FOR && cpipe->res_word != RES_IN) continue; /* current word is FOR or IN (BOLD in comments below) */ if (cpipe->next == NULL) { syntax_error("malformed for"); debug_leave(); debug_printf_exec("run_list lvl %d return 1\n", G.run_list_level); return 1; } /* "FOR v; do ..." and "for v IN a b; do..." are ok */ if (cpipe->next->res_word == RES_DO) continue; /* next word is not "do". It must be "in" then ("FOR v in ...") */ if (cpipe->res_word == RES_IN /* "for v IN a b; not_do..."? */ || cpipe->next->res_word != RES_IN /* FOR v not_do_and_not_in..."? */ ) { syntax_error("malformed for"); debug_leave(); debug_printf_exec("run_list lvl %d return 1\n", G.run_list_level); return 1; } } #endif /* Past this point, all code paths should jump to ret: label * in order to return, no direct "return" statements please. * This helps to ensure that no memory is leaked. */ #if ENABLE_HUSH_JOB G.run_list_level++; #endif #if HAS_KEYWORDS rword = RES_NONE; last_rword = RES_XXXX; #endif last_followup = PIPE_SEQ; rcode = G.last_exitcode; /* Go through list of pipes, (maybe) executing them. */ for (; pi; pi = IF_HUSH_LOOPS(rword == RES_DONE ? loop_top : ) pi->next) { if (G.flag_SIGINT) break; IF_HAS_KEYWORDS(rword = pi->res_word;) debug_printf_exec(": rword=%d cond_code=%d last_rword=%d\n", rword, cond_code, last_rword); #if ENABLE_HUSH_LOOPS if ((rword == RES_WHILE || rword == RES_UNTIL || rword == RES_FOR) && loop_top == NULL /* avoid bumping G.depth_of_loop twice */ ) { /* start of a loop: remember where loop starts */ loop_top = pi; G.depth_of_loop++; } #endif /* Still in the same "if...", "then..." or "do..." branch? */ if (IF_HAS_KEYWORDS(rword == last_rword &&) 1) { if ((rcode == 0 && last_followup == PIPE_OR) || (rcode != 0 && last_followup == PIPE_AND) ) { /* It is " || CMD" or " && CMD" * and we should not execute CMD */ debug_printf_exec("skipped cmd because of || or &&\n"); last_followup = pi->followup; continue; } } last_followup = pi->followup; IF_HAS_KEYWORDS(last_rword = rword;) #if ENABLE_HUSH_IF if (cond_code) { if (rword == RES_THEN) { /* if false; then ... fi has exitcode 0! */ G.last_exitcode = rcode = EXIT_SUCCESS; /* "if THEN cmd": skip cmd */ continue; } } else { if (rword == RES_ELSE || rword == RES_ELIF) { /* "if then ... ELSE/ELIF cmd": * skip cmd and all following ones */ break; } } #endif #if ENABLE_HUSH_LOOPS if (rword == RES_FOR) { /* && pi->num_cmds - always == 1 */ if (!for_lcur) { /* first loop through for */ static const char encoded_dollar_at[] ALIGN1 = { SPECIAL_VAR_SYMBOL, '@' | 0x80, SPECIAL_VAR_SYMBOL, '\0' }; /* encoded representation of "$@" */ static const char *const encoded_dollar_at_argv[] = { encoded_dollar_at, NULL }; /* argv list with one element: "$@" */ char **vals; vals = (char**)encoded_dollar_at_argv; if (pi->next->res_word == RES_IN) { /* if no variable values after "in" we skip "for" */ if (!pi->next->cmds[0].argv) { G.last_exitcode = rcode = EXIT_SUCCESS; debug_printf_exec(": null FOR: exitcode EXIT_SUCCESS\n"); break; } vals = pi->next->cmds[0].argv; } /* else: "for var; do..." -> assume "$@" list */ /* create list of variable values */ debug_print_strings("for_list made from", vals); for_list = expand_strvec_to_strvec(vals); for_lcur = for_list; debug_print_strings("for_list", for_list); } if (!*for_lcur) { /* "for" loop is over, clean up */ free(for_list); for_list = NULL; for_lcur = NULL; break; } /* Insert next value from for_lcur */ /* note: *for_lcur already has quotes removed, $var expanded, etc */ set_local_var(xasprintf("%s=%s", pi->cmds[0].argv[0], *for_lcur++), /*exp:*/ 0, /*lvl:*/ 0, /*ro:*/ 0); continue; } if (rword == RES_IN) { continue; /* "for v IN list;..." - "in" has no cmds anyway */ } if (rword == RES_DONE) { continue; /* "done" has no cmds too */ } #endif #if ENABLE_HUSH_CASE if (rword == RES_CASE) { case_word = expand_strvec_to_string(pi->cmds->argv); continue; } if (rword == RES_MATCH) { char **argv; if (!case_word) /* "case ... matched_word) ... WORD)": we executed selected branch, stop */ break; /* all prev words didn't match, does this one match? */ argv = pi->cmds->argv; while (*argv) { char *pattern = expand_string_to_string(*argv); /* TODO: which FNM_xxx flags to use? */ cond_code = (fnmatch(pattern, case_word, /*flags:*/ 0) != 0); free(pattern); if (cond_code == 0) { /* match! we will execute this branch */ free(case_word); /* make future "word)" stop */ case_word = NULL; break; } argv++; } continue; } if (rword == RES_CASE_BODY) { /* inside of a case branch */ if (cond_code != 0) continue; /* not matched yet, skip this pipe */ } #endif /* Just pressing in shell should check for jobs. * OTOH, in non-interactive shell this is useless * and only leads to extra job checks */ if (pi->num_cmds == 0) { if (G_interactive_fd) goto check_jobs_and_continue; continue; } /* After analyzing all keywords and conditions, we decided * to execute this pipe. NB: have to do checkjobs(NULL) * after run_pipe to collect any background children, * even if list execution is to be stopped. */ debug_printf_exec(": run_pipe with %d members\n", pi->num_cmds); { int r; #if ENABLE_HUSH_LOOPS G.flag_break_continue = 0; #endif rcode = r = run_pipe(pi); /* NB: rcode is a smallint */ if (r != -1) { /* We ran a builtin, function, or group. * rcode is already known * and we don't need to wait for anything. */ G.last_exitcode = rcode; debug_printf_exec(": builtin/func exitcode %d\n", rcode); check_and_run_traps(0); #if ENABLE_HUSH_LOOPS /* Was it "break" or "continue"? */ if (G.flag_break_continue) { smallint fbc = G.flag_break_continue; /* We might fall into outer *loop*, * don't want to break it too */ if (loop_top) { G.depth_break_continue--; if (G.depth_break_continue == 0) G.flag_break_continue = 0; /* else: e.g. "continue 2" should *break* once, *then* continue */ } /* else: "while... do... { we are here (innermost list is not a loop!) };...done" */ if (G.depth_break_continue != 0 || fbc == BC_BREAK) goto check_jobs_and_break; /* "continue": simulate end of loop */ rword = RES_DONE; continue; } #endif #if ENABLE_HUSH_FUNCTIONS if (G.flag_return_in_progress == 1) { /* same as "goto check_jobs_and_break" */ checkjobs(NULL); break; } #endif } else if (pi->followup == PIPE_BG) { /* What does bash do with attempts to background builtins? */ /* even bash 3.2 doesn't do that well with nested bg: * try "{ { sleep 10; echo DEEP; } & echo HERE; } &". * I'm NOT treating inner &'s as jobs */ check_and_run_traps(0); #if ENABLE_HUSH_JOB if (G.run_list_level == 1) insert_bg_job(pi); #endif G.last_exitcode = rcode = EXIT_SUCCESS; debug_printf_exec(": cmd&: exitcode EXIT_SUCCESS\n"); } else { #if ENABLE_HUSH_JOB if (G.run_list_level == 1 && G_interactive_fd) { /* Waits for completion, then fg's main shell */ rcode = checkjobs_and_fg_shell(pi); debug_printf_exec(": checkjobs_and_fg_shell exitcode %d\n", rcode); check_and_run_traps(0); } else #endif { /* This one just waits for completion */ rcode = checkjobs(pi); debug_printf_exec(": checkjobs exitcode %d\n", rcode); check_and_run_traps(0); } G.last_exitcode = rcode; } } /* Analyze how result affects subsequent commands */ #if ENABLE_HUSH_IF if (rword == RES_IF || rword == RES_ELIF) cond_code = rcode; #endif #if ENABLE_HUSH_LOOPS /* Beware of "while false; true; do ..."! */ if (pi->next && pi->next->res_word == RES_DO) { if (rword == RES_WHILE) { if (rcode) { /* "while false; do...done" - exitcode 0 */ G.last_exitcode = rcode = EXIT_SUCCESS; debug_printf_exec(": while expr is false: breaking (exitcode:EXIT_SUCCESS)\n"); goto check_jobs_and_break; } } if (rword == RES_UNTIL) { if (!rcode) { debug_printf_exec(": until expr is true: breaking\n"); check_jobs_and_break: checkjobs(NULL); break; } } } #endif check_jobs_and_continue: checkjobs(NULL); } /* for (pi) */ #if ENABLE_HUSH_JOB G.run_list_level--; #endif #if ENABLE_HUSH_LOOPS if (loop_top) G.depth_of_loop--; free(for_list); #endif #if ENABLE_HUSH_CASE free(case_word); #endif debug_leave(); debug_printf_exec("run_list lvl %d return %d\n", G.run_list_level + 1, rcode); return rcode; } /* Select which version we will use */ static int run_and_free_list(struct pipe *pi) { int rcode = 0; debug_printf_exec("run_and_free_list entered\n"); if (!G.fake_mode) { debug_printf_exec(": run_list: 1st pipe with %d cmds\n", pi->num_cmds); rcode = run_list(pi); } /* free_pipe_list has the side effect of clearing memory. * In the long run that function can be merged with run_list, * but doing that now would hobble the debugging effort. */ free_pipe_list(pi); debug_printf_exec("run_and_free_list return %d\n", rcode); return rcode; } static struct pipe *new_pipe(void) { struct pipe *pi; pi = xzalloc(sizeof(struct pipe)); /*pi->followup = 0; - deliberately invalid value */ /*pi->res_word = RES_NONE; - RES_NONE is 0 anyway */ return pi; } /* Command (member of a pipe) is complete, or we start a new pipe * if ctx->command is NULL. * No errors possible here. */ static int done_command(struct parse_context *ctx) { /* The command is really already in the pipe structure, so * advance the pipe counter and make a new, null command. */ struct pipe *pi = ctx->pipe; struct command *command = ctx->command; if (command) { if (IS_NULL_CMD(command)) { debug_printf_parse("done_command: skipping null cmd, num_cmds=%d\n", pi->num_cmds); goto clear_and_ret; } pi->num_cmds++; debug_printf_parse("done_command: ++num_cmds=%d\n", pi->num_cmds); //debug_print_tree(ctx->list_head, 20); } else { debug_printf_parse("done_command: initializing, num_cmds=%d\n", pi->num_cmds); } /* Only real trickiness here is that the uncommitted * command structure is not counted in pi->num_cmds. */ pi->cmds = xrealloc(pi->cmds, sizeof(*pi->cmds) * (pi->num_cmds+1)); ctx->command = command = &pi->cmds[pi->num_cmds]; clear_and_ret: memset(command, 0, sizeof(*command)); return pi->num_cmds; /* used only for 0/nonzero check */ } static void done_pipe(struct parse_context *ctx, pipe_style type) { int not_null; debug_printf_parse("done_pipe entered, followup %d\n", type); /* Close previous command */ not_null = done_command(ctx); ctx->pipe->followup = type; #if HAS_KEYWORDS ctx->pipe->pi_inverted = ctx->ctx_inverted; ctx->ctx_inverted = 0; ctx->pipe->res_word = ctx->ctx_res_w; #endif /* Without this check, even just on command line generates * tree of three NOPs (!). Which is harmless but annoying. * IOW: it is safe to do it unconditionally. */ if (not_null #if ENABLE_HUSH_IF || ctx->ctx_res_w == RES_FI #endif #if ENABLE_HUSH_LOOPS || ctx->ctx_res_w == RES_DONE || ctx->ctx_res_w == RES_FOR || ctx->ctx_res_w == RES_IN #endif #if ENABLE_HUSH_CASE || ctx->ctx_res_w == RES_ESAC #endif ) { struct pipe *new_p; debug_printf_parse("done_pipe: adding new pipe: " "not_null:%d ctx->ctx_res_w:%d\n", not_null, ctx->ctx_res_w); new_p = new_pipe(); ctx->pipe->next = new_p; ctx->pipe = new_p; /* RES_THEN, RES_DO etc are "sticky" - * they remain set for pipes inside if/while. * This is used to control execution. * RES_FOR and RES_IN are NOT sticky (needed to support * cases where variable or value happens to match a keyword): */ #if ENABLE_HUSH_LOOPS if (ctx->ctx_res_w == RES_FOR || ctx->ctx_res_w == RES_IN) ctx->ctx_res_w = RES_NONE; #endif #if ENABLE_HUSH_CASE if (ctx->ctx_res_w == RES_MATCH) ctx->ctx_res_w = RES_CASE_BODY; if (ctx->ctx_res_w == RES_CASE) ctx->ctx_res_w = RES_CASE_IN; #endif ctx->command = NULL; /* trick done_command below */ /* Create the memory for command, roughly: * ctx->pipe->cmds = new struct command; * ctx->command = &ctx->pipe->cmds[0]; */ done_command(ctx); //debug_print_tree(ctx->list_head, 10); } debug_printf_parse("done_pipe return\n"); } static void initialize_context(struct parse_context *ctx) { memset(ctx, 0, sizeof(*ctx)); ctx->pipe = ctx->list_head = new_pipe(); /* Create the memory for command, roughly: * ctx->pipe->cmds = new struct command; * ctx->command = &ctx->pipe->cmds[0]; */ done_command(ctx); } /* If a reserved word is found and processed, parse context is modified * and 1 is returned. */ #if HAS_KEYWORDS struct reserved_combo { char literal[6]; unsigned char res; unsigned char assignment_flag; int flag; }; enum { FLAG_END = (1 << RES_NONE ), # if ENABLE_HUSH_IF FLAG_IF = (1 << RES_IF ), FLAG_THEN = (1 << RES_THEN ), FLAG_ELIF = (1 << RES_ELIF ), FLAG_ELSE = (1 << RES_ELSE ), FLAG_FI = (1 << RES_FI ), # endif # if ENABLE_HUSH_LOOPS FLAG_FOR = (1 << RES_FOR ), FLAG_WHILE = (1 << RES_WHILE), FLAG_UNTIL = (1 << RES_UNTIL), FLAG_DO = (1 << RES_DO ), FLAG_DONE = (1 << RES_DONE ), FLAG_IN = (1 << RES_IN ), # endif # if ENABLE_HUSH_CASE FLAG_MATCH = (1 << RES_MATCH), FLAG_ESAC = (1 << RES_ESAC ), # endif FLAG_START = (1 << RES_XXXX ), }; static const struct reserved_combo* match_reserved_word(o_string *word) { /* Mostly a list of accepted follow-up reserved words. * FLAG_END means we are done with the sequence, and are ready * to turn the compound list into a command. * FLAG_START means the word must start a new compound list. */ static const struct reserved_combo reserved_list[] = { # if ENABLE_HUSH_IF { "!", RES_NONE, NOT_ASSIGNMENT , 0 }, { "if", RES_IF, WORD_IS_KEYWORD, FLAG_THEN | FLAG_START }, { "then", RES_THEN, WORD_IS_KEYWORD, FLAG_ELIF | FLAG_ELSE | FLAG_FI }, { "elif", RES_ELIF, WORD_IS_KEYWORD, FLAG_THEN }, { "else", RES_ELSE, WORD_IS_KEYWORD, FLAG_FI }, { "fi", RES_FI, NOT_ASSIGNMENT , FLAG_END }, # endif # if ENABLE_HUSH_LOOPS { "for", RES_FOR, NOT_ASSIGNMENT , FLAG_IN | FLAG_DO | FLAG_START }, { "while", RES_WHILE, WORD_IS_KEYWORD, FLAG_DO | FLAG_START }, { "until", RES_UNTIL, WORD_IS_KEYWORD, FLAG_DO | FLAG_START }, { "in", RES_IN, NOT_ASSIGNMENT , FLAG_DO }, { "do", RES_DO, WORD_IS_KEYWORD, FLAG_DONE }, { "done", RES_DONE, NOT_ASSIGNMENT , FLAG_END }, # endif # if ENABLE_HUSH_CASE { "case", RES_CASE, NOT_ASSIGNMENT , FLAG_MATCH | FLAG_START }, { "esac", RES_ESAC, NOT_ASSIGNMENT , FLAG_END }, # endif }; const struct reserved_combo *r; for (r = reserved_list; r < reserved_list + ARRAY_SIZE(reserved_list); r++) { if (strcmp(word->data, r->literal) == 0) return r; } return NULL; } /* Return 0: not a keyword, 1: keyword */ static int reserved_word(o_string *word, struct parse_context *ctx) { # if ENABLE_HUSH_CASE static const struct reserved_combo reserved_match = { "", RES_MATCH, NOT_ASSIGNMENT , FLAG_MATCH | FLAG_ESAC }; # endif const struct reserved_combo *r; if (word->o_quoted) return 0; r = match_reserved_word(word); if (!r) return 0; debug_printf("found reserved word %s, res %d\n", r->literal, r->res); # if ENABLE_HUSH_CASE if (r->res == RES_IN && ctx->ctx_res_w == RES_CASE_IN) { /* "case word IN ..." - IN part starts first MATCH part */ r = &reserved_match; } else # endif if (r->flag == 0) { /* '!' */ if (ctx->ctx_inverted) { /* bash doesn't accept '! ! true' */ syntax_error("! ! command"); ctx->ctx_res_w = RES_SNTX; } ctx->ctx_inverted = 1; return 1; } if (r->flag & FLAG_START) { struct parse_context *old; old = xmalloc(sizeof(*old)); debug_printf_parse("push stack %p\n", old); *old = *ctx; /* physical copy */ initialize_context(ctx); ctx->stack = old; } else if (/*ctx->ctx_res_w == RES_NONE ||*/ !(ctx->old_flag & (1 << r->res))) { syntax_error_at(word->data); ctx->ctx_res_w = RES_SNTX; return 1; } else { /* "{...} fi" is ok. "{...} if" is not * Example: * if { echo foo; } then { echo bar; } fi */ if (ctx->command->group) done_pipe(ctx, PIPE_SEQ); } ctx->ctx_res_w = r->res; ctx->old_flag = r->flag; word->o_assignment = r->assignment_flag; if (ctx->old_flag & FLAG_END) { struct parse_context *old; done_pipe(ctx, PIPE_SEQ); debug_printf_parse("pop stack %p\n", ctx->stack); old = ctx->stack; old->command->group = ctx->list_head; old->command->cmd_type = CMD_NORMAL; # if !BB_MMU o_addstr(&old->as_string, ctx->as_string.data); o_free_unsafe(&ctx->as_string); old->command->group_as_string = xstrdup(old->as_string.data); debug_printf_parse("pop, remembering as:'%s'\n", old->command->group_as_string); # endif *ctx = *old; /* physical copy */ free(old); } return 1; } #endif /* HAS_KEYWORDS */ /* Word is complete, look at it and update parsing context. * Normal return is 0. Syntax errors return 1. * Note: on return, word is reset, but not o_free'd! */ static int done_word(o_string *word, struct parse_context *ctx) { struct command *command = ctx->command; debug_printf_parse("done_word entered: '%s' %p\n", word->data, command); if (word->length == 0 && word->o_quoted == 0) { debug_printf_parse("done_word return 0: true null, ignored\n"); return 0; } if (ctx->pending_redirect) { /* We do not glob in e.g. >*.tmp case. bash seems to glob here * only if run as "bash", not "sh" */ /* http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html * "2.7 Redirection * ...the word that follows the redirection operator * shall be subjected to tilde expansion, parameter expansion, * command substitution, arithmetic expansion, and quote * removal. Pathname expansion shall not be performed * on the word by a non-interactive shell; an interactive * shell may perform it, but shall do so only when * the expansion would result in one word." */ ctx->pending_redirect->rd_filename = xstrdup(word->data); /* Cater for >\file case: * >\a creates file a; >\\a, >"\a", >"\\a" create file \a * Same with heredocs: * for <<\H delim is H; <<\\H, <<"\H", <<"\\H" - \H */ if (ctx->pending_redirect->rd_type == REDIRECT_HEREDOC) { unbackslash(ctx->pending_redirect->rd_filename); /* Is it <<"HEREDOC"? */ if (word->o_quoted) { ctx->pending_redirect->rd_dup |= HEREDOC_QUOTED; } } debug_printf_parse("word stored in rd_filename: '%s'\n", word->data); ctx->pending_redirect = NULL; } else { /* If this word wasn't an assignment, next ones definitely * can't be assignments. Even if they look like ones. */ if (word->o_assignment != DEFINITELY_ASSIGNMENT && word->o_assignment != WORD_IS_KEYWORD ) { word->o_assignment = NOT_ASSIGNMENT; } else { if (word->o_assignment == DEFINITELY_ASSIGNMENT) command->assignment_cnt++; word->o_assignment = MAYBE_ASSIGNMENT; } #if HAS_KEYWORDS # if ENABLE_HUSH_CASE if (ctx->ctx_dsemicolon && strcmp(word->data, "esac") != 0 /* not "... pattern) cmd;; esac" */ ) { /* already done when ctx_dsemicolon was set to 1: */ /* ctx->ctx_res_w = RES_MATCH; */ ctx->ctx_dsemicolon = 0; } else # endif if (!command->argv /* if it's the first word... */ # if ENABLE_HUSH_LOOPS && ctx->ctx_res_w != RES_FOR /* ...not after FOR or IN */ && ctx->ctx_res_w != RES_IN # endif # if ENABLE_HUSH_CASE && ctx->ctx_res_w != RES_CASE # endif ) { debug_printf_parse("checking '%s' for reserved-ness\n", word->data); if (reserved_word(word, ctx)) { o_reset_to_empty_unquoted(word); debug_printf_parse("done_word return %d\n", (ctx->ctx_res_w == RES_SNTX)); return (ctx->ctx_res_w == RES_SNTX); } # ifdef CMD_SINGLEWORD_NOGLOB_COND if (strcmp(word->data, "export") == 0 # if ENABLE_HUSH_LOCAL || strcmp(word->data, "local") == 0 # endif ) { command->cmd_type = CMD_SINGLEWORD_NOGLOB_COND; } else # endif # if ENABLE_HUSH_BASH_COMPAT if (strcmp(word->data, "[[") == 0) { command->cmd_type = CMD_SINGLEWORD_NOGLOB; } /* fall through */ # endif } #endif if (command->group) { /* "{ echo foo; } echo bar" - bad */ syntax_error_at(word->data); debug_printf_parse("done_word return 1: syntax error, " "groups and arglists don't mix\n"); return 1; } if (word->o_quoted /* word had "xx" or 'xx' at least as part of it. */ /* optimization: and if it's ("" or '') or ($v... or `cmd`...): */ && (word->data[0] == '\0' || word->data[0] == SPECIAL_VAR_SYMBOL) /* (otherwise it's known to be not empty and is already safe) */ ) { /* exclude "$@" - it can expand to no word despite "" */ char *p = word->data; while (p[0] == SPECIAL_VAR_SYMBOL && (p[1] & 0x7f) == '@' && p[2] == SPECIAL_VAR_SYMBOL ) { p += 3; } if (p == word->data || p[0] != '\0') { /* saw no "$@", or not only "$@" but some * real text is there too */ /* insert "empty variable" reference, this makes * e.g. "", $empty"" etc to not disappear */ o_addchr(word, SPECIAL_VAR_SYMBOL); o_addchr(word, SPECIAL_VAR_SYMBOL); } } command->argv = add_string_to_strings(command->argv, xstrdup(word->data)); debug_print_strings("word appended to argv", command->argv); } #if ENABLE_HUSH_LOOPS if (ctx->ctx_res_w == RES_FOR) { if (word->o_quoted || !is_well_formed_var_name(command->argv[0], '\0') ) { /* bash says just "not a valid identifier" */ syntax_error("not a valid identifier in for"); return 1; } /* Force FOR to have just one word (variable name) */ /* NB: basically, this makes hush see "for v in ..." * syntax as if it is "for v; in ...". FOR and IN become * two pipe structs in parse tree. */ done_pipe(ctx, PIPE_SEQ); } #endif #if ENABLE_HUSH_CASE /* Force CASE to have just one word */ if (ctx->ctx_res_w == RES_CASE) { done_pipe(ctx, PIPE_SEQ); } #endif o_reset_to_empty_unquoted(word); debug_printf_parse("done_word return 0\n"); return 0; } /* Peek ahead in the input to find out if we have a "&n" construct, * as in "2>&1", that represents duplicating a file descriptor. * Return: * REDIRFD_CLOSE if >&- "close fd" construct is seen, * REDIRFD_SYNTAX_ERR if syntax error, * REDIRFD_TO_FILE if no & was seen, * or the number found. */ #if BB_MMU #define parse_redir_right_fd(as_string, input) \ parse_redir_right_fd(input) #endif static int parse_redir_right_fd(o_string *as_string, struct in_str *input) { int ch, d, ok; ch = i_peek(input); if (ch != '&') return REDIRFD_TO_FILE; ch = i_getch(input); /* get the & */ nommu_addchr(as_string, ch); ch = i_peek(input); if (ch == '-') { ch = i_getch(input); nommu_addchr(as_string, ch); return REDIRFD_CLOSE; } d = 0; ok = 0; while (ch != EOF && isdigit(ch)) { d = d*10 + (ch-'0'); ok = 1; ch = i_getch(input); nommu_addchr(as_string, ch); ch = i_peek(input); } if (ok) return d; //TODO: this is the place to catch ">&file" bashism (redirect both fd 1 and 2) bb_error_msg("ambiguous redirect"); return REDIRFD_SYNTAX_ERR; } /* Return code is 0 normal, 1 if a syntax error is detected */ static int parse_redirect(struct parse_context *ctx, int fd, redir_type style, struct in_str *input) { struct command *command = ctx->command; struct redir_struct *redir; struct redir_struct **redirp; int dup_num; dup_num = REDIRFD_TO_FILE; if (style != REDIRECT_HEREDOC) { /* Check for a '>&1' type redirect */ dup_num = parse_redir_right_fd(&ctx->as_string, input); if (dup_num == REDIRFD_SYNTAX_ERR) return 1; } else { int ch = i_peek(input); dup_num = (ch == '-'); /* HEREDOC_SKIPTABS bit is 1 */ if (dup_num) { /* <<-... */ ch = i_getch(input); nommu_addchr(&ctx->as_string, ch); ch = i_peek(input); } } if (style == REDIRECT_OVERWRITE && dup_num == REDIRFD_TO_FILE) { int ch = i_peek(input); if (ch == '|') { /* >|FILE redirect ("clobbering" >). * Since we do not support "set -o noclobber" yet, * >| and > are the same for now. Just eat |. */ ch = i_getch(input); nommu_addchr(&ctx->as_string, ch); } } /* Create a new redir_struct and append it to the linked list */ redirp = &command->redirects; while ((redir = *redirp) != NULL) { redirp = &(redir->next); } *redirp = redir = xzalloc(sizeof(*redir)); /* redir->next = NULL; */ /* redir->rd_filename = NULL; */ redir->rd_type = style; redir->rd_fd = (fd == -1) ? redir_table[style].default_fd : fd; debug_printf_parse("redirect type %d %s\n", redir->rd_fd, redir_table[style].descrip); redir->rd_dup = dup_num; if (style != REDIRECT_HEREDOC && dup_num != REDIRFD_TO_FILE) { /* Erik had a check here that the file descriptor in question * is legit; I postpone that to "run time" * A "-" representation of "close me" shows up as a -3 here */ debug_printf_parse("duplicating redirect '%d>&%d'\n", redir->rd_fd, redir->rd_dup); } else { /* Set ctx->pending_redirect, so we know what to do at the * end of the next parsed word. */ ctx->pending_redirect = redir; } return 0; } /* If a redirect is immediately preceded by a number, that number is * supposed to tell which file descriptor to redirect. This routine * looks for such preceding numbers. In an ideal world this routine * needs to handle all the following classes of redirects... * echo 2>foo # redirects fd 2 to file "foo", nothing passed to echo * echo 49>foo # redirects fd 49 to file "foo", nothing passed to echo * echo -2>foo # redirects fd 1 to file "foo", "-2" passed to echo * echo 49x>foo # redirects fd 1 to file "foo", "49x" passed to echo * * http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html * "2.7 Redirection * ... If n is quoted, the number shall not be recognized as part of * the redirection expression. For example: * echo \2>a * writes the character 2 into file a" * We are getting it right by setting ->o_quoted on any \ * * A -1 return means no valid number was found, * the caller should use the appropriate default for this redirection. */ static int redirect_opt_num(o_string *o) { int num; if (o->data == NULL) return -1; num = bb_strtou(o->data, NULL, 10); if (errno || num < 0) return -1; o_reset_to_empty_unquoted(o); return num; } #if BB_MMU #define fetch_till_str(as_string, input, word, skip_tabs) \ fetch_till_str(input, word, skip_tabs) #endif static char *fetch_till_str(o_string *as_string, struct in_str *input, const char *word, int skip_tabs) { o_string heredoc = NULL_O_STRING; int past_EOL = 0; int ch; goto jump_in; while (1) { ch = i_getch(input); nommu_addchr(as_string, ch); if (ch == '\n') { if (strcmp(heredoc.data + past_EOL, word) == 0) { heredoc.data[past_EOL] = '\0'; debug_printf_parse("parsed heredoc '%s'\n", heredoc.data); return heredoc.data; } do { o_addchr(&heredoc, ch); past_EOL = heredoc.length; jump_in: do { ch = i_getch(input); nommu_addchr(as_string, ch); } while (skip_tabs && ch == '\t'); } while (ch == '\n'); } if (ch == EOF) { o_free_unsafe(&heredoc); return NULL; } o_addchr(&heredoc, ch); nommu_addchr(as_string, ch); } } /* Look at entire parse tree for not-yet-loaded REDIRECT_HEREDOCs * and load them all. There should be exactly heredoc_cnt of them. */ static int fetch_heredocs(int heredoc_cnt, struct parse_context *ctx, struct in_str *input) { struct pipe *pi = ctx->list_head; while (pi && heredoc_cnt) { int i; struct command *cmd = pi->cmds; debug_printf_parse("fetch_heredocs: num_cmds:%d cmd argv0:'%s'\n", pi->num_cmds, cmd->argv ? cmd->argv[0] : "NONE"); for (i = 0; i < pi->num_cmds; i++) { struct redir_struct *redir = cmd->redirects; debug_printf_parse("fetch_heredocs: %d cmd argv0:'%s'\n", i, cmd->argv ? cmd->argv[0] : "NONE"); while (redir) { if (redir->rd_type == REDIRECT_HEREDOC) { char *p; redir->rd_type = REDIRECT_HEREDOC2; /* redir->rd_dup is (ab)used to indicate <<- */ p = fetch_till_str(&ctx->as_string, input, redir->rd_filename, redir->rd_dup & HEREDOC_SKIPTABS); if (!p) { syntax_error("unexpected EOF in here document"); return 1; } free(redir->rd_filename); redir->rd_filename = p; heredoc_cnt--; } redir = redir->next; } cmd++; } pi = pi->next; } #if 0 /* Should be 0. If it isn't, it's a parse error */ if (heredoc_cnt) bb_error_msg_and_die("heredoc BUG 2"); #endif return 0; } #if ENABLE_HUSH_TICK static FILE *generate_stream_from_string(const char *s, pid_t *pid_p) { pid_t pid; int channel[2]; # if !BB_MMU char **to_free = NULL; # endif xpipe(channel); pid = BB_MMU ? fork() : vfork(); if (pid < 0) bb_perror_msg_and_die(BB_MMU ? "fork" : "vfork"); if (pid == 0) { /* child */ disable_restore_tty_pgrp_on_exit(); /* Process substitution is not considered to be usual * 'command execution'. * SUSv3 says ctrl-Z should be ignored, ctrl-C should not. */ bb_signals(0 + (1 << SIGTSTP) + (1 << SIGTTIN) + (1 << SIGTTOU) , SIG_IGN); CLEAR_RANDOM_T(&G.random_gen); /* or else $RANDOM repeats in child */ close(channel[0]); /* NB: close _first_, then move fd! */ xmove_fd(channel[1], 1); /* Prevent it from trying to handle ctrl-z etc */ IF_HUSH_JOB(G.run_list_level = 1;) /* Awful hack for `trap` or $(trap). * * http://www.opengroup.org/onlinepubs/009695399/utilities/trap.html * contains an example where "trap" is executed in a subshell: * * save_traps=$(trap) * ... * eval "$save_traps" * * Standard does not say that "trap" in subshell shall print * parent shell's traps. It only says that its output * must have suitable form, but then, in the above example * (which is not supposed to be normative), it implies that. * * bash (and probably other shell) does implement it * (traps are reset to defaults, but "trap" still shows them), * but as a result, "trap" logic is hopelessly messed up: * * # trap * trap -- 'echo Ho' SIGWINCH <--- we have a handler * # (trap) <--- trap is in subshell - no output (correct, traps are reset) * # true | trap <--- trap is in subshell - no output (ditto) * # echo `true | trap` <--- in subshell - output (but traps are reset!) * trap -- 'echo Ho' SIGWINCH * # echo `(trap)` <--- in subshell in subshell - output * trap -- 'echo Ho' SIGWINCH * # echo `true | (trap)` <--- in subshell in subshell in subshell - output! * trap -- 'echo Ho' SIGWINCH * * The rules when to forget and when to not forget traps * get really complex and nonsensical. * * Our solution: ONLY bare $(trap) or `trap` is special. */ s = skip_whitespace(s); if (strncmp(s, "trap", 4) == 0 && (*skip_whitespace(s + 4) == '\0')) { static const char *const argv[] = { NULL, NULL }; builtin_trap((char**)argv); exit(0); /* not _exit() - we need to fflush */ } # if BB_MMU reset_traps_to_defaults(); parse_and_run_string(s); _exit(G.last_exitcode); # else /* We re-execute after vfork on NOMMU. This makes this script safe: * yes "0123456789012345678901234567890" | dd bs=32 count=64k >BIG * huge=`cat BIG` # was blocking here forever * echo OK */ re_execute_shell(&to_free, s, G.global_argv[0], G.global_argv + 1, NULL); # endif } /* parent */ *pid_p = pid; # if ENABLE_HUSH_FAST G.count_SIGCHLD++; //bb_error_msg("[%d] fork in generate_stream_from_string: G.count_SIGCHLD:%d G.handled_SIGCHLD:%d", getpid(), G.count_SIGCHLD, G.handled_SIGCHLD); # endif enable_restore_tty_pgrp_on_exit(); # if !BB_MMU free(to_free); # endif close(channel[1]); close_on_exec_on(channel[0]); return xfdopen_for_read(channel[0]); } /* Return code is exit status of the process that is run. */ static int process_command_subs(o_string *dest, const char *s) { FILE *fp; struct in_str pipe_str; pid_t pid; int status, ch, eol_cnt; fp = generate_stream_from_string(s, &pid); /* Now send results of command back into original context */ setup_file_in_str(&pipe_str, fp); eol_cnt = 0; while ((ch = i_getch(&pipe_str)) != EOF) { if (ch == '\n') { eol_cnt++; continue; } while (eol_cnt) { o_addchr(dest, '\n'); eol_cnt--; } o_addQchr(dest, ch); } debug_printf("done reading from `cmd` pipe, closing it\n"); fclose(fp); /* We need to extract exitcode. Test case * "true; echo `sleep 1; false` $?" * should print 1 */ safe_waitpid(pid, &status, 0); debug_printf("child exited. returning its exitcode:%d\n", WEXITSTATUS(status)); return WEXITSTATUS(status); } #endif /* ENABLE_HUSH_TICK */ #if !ENABLE_HUSH_FUNCTIONS #define parse_group(dest, ctx, input, ch) \ parse_group(ctx, input, ch) #endif static int parse_group(o_string *dest, struct parse_context *ctx, struct in_str *input, int ch) { /* dest contains characters seen prior to ( or {. * Typically it's empty, but for function defs, * it contains function name (without '()'). */ struct pipe *pipe_list; int endch; struct command *command = ctx->command; debug_printf_parse("parse_group entered\n"); #if ENABLE_HUSH_FUNCTIONS if (ch == '(' && !dest->o_quoted) { if (dest->length) if (done_word(dest, ctx)) return 1; if (!command->argv) goto skip; /* (... */ if (command->argv[1]) { /* word word ... (... */ syntax_error_unexpected_ch('('); return 1; } /* it is "word(..." or "word (..." */ do ch = i_getch(input); while (ch == ' ' || ch == '\t'); if (ch != ')') { syntax_error_unexpected_ch(ch); return 1; } nommu_addchr(&ctx->as_string, ch); do ch = i_getch(input); while (ch == ' ' || ch == '\t' || ch == '\n'); if (ch != '{') { syntax_error_unexpected_ch(ch); return 1; } nommu_addchr(&ctx->as_string, ch); command->cmd_type = CMD_FUNCDEF; goto skip; } #endif #if 0 /* Prevented by caller */ if (command->argv /* word [word]{... */ || dest->length /* word{... */ || dest->o_quoted /* ""{... */ ) { syntax_error(NULL); debug_printf_parse("parse_group return 1: " "syntax error, groups and arglists don't mix\n"); return 1; } #endif #if ENABLE_HUSH_FUNCTIONS skip: #endif endch = '}'; if (ch == '(') { endch = ')'; command->cmd_type = CMD_SUBSHELL; } else { /* bash does not allow "{echo...", requires whitespace */ ch = i_getch(input); if (ch != ' ' && ch != '\t' && ch != '\n') { syntax_error_unexpected_ch(ch); return 1; } nommu_addchr(&ctx->as_string, ch); } { #if !BB_MMU char *as_string = NULL; #endif pipe_list = parse_stream(&as_string, input, endch); #if !BB_MMU if (as_string) o_addstr(&ctx->as_string, as_string); #endif /* empty ()/{} or parse error? */ if (!pipe_list || pipe_list == ERR_PTR) { /* parse_stream already emitted error msg */ #if !BB_MMU free(as_string); #endif debug_printf_parse("parse_group return 1: " "parse_stream returned %p\n", pipe_list); return 1; } command->group = pipe_list; #if !BB_MMU as_string[strlen(as_string) - 1] = '\0'; /* plink ')' or '}' */ command->group_as_string = as_string; debug_printf_parse("end of group, remembering as:'%s'\n", command->group_as_string); #endif } debug_printf_parse("parse_group return 0\n"); return 0; /* command remains "open", available for possible redirects */ } #if ENABLE_HUSH_TICK || ENABLE_SH_MATH_SUPPORT /* Subroutines for copying $(...) and `...` things */ static void add_till_backquote(o_string *dest, struct in_str *input); /* '...' */ static void add_till_single_quote(o_string *dest, struct in_str *input) { while (1) { int ch = i_getch(input); if (ch == EOF) { syntax_error_unterm_ch('\''); /*xfunc_die(); - redundant */ } if (ch == '\'') return; o_addchr(dest, ch); } } /* "...\"...`..`...." - do we need to handle "...$(..)..." too? */ static void add_till_double_quote(o_string *dest, struct in_str *input) { while (1) { int ch = i_getch(input); if (ch == EOF) { syntax_error_unterm_ch('"'); /*xfunc_die(); - redundant */ } if (ch == '"') return; if (ch == '\\') { /* \x. Copy both chars. */ o_addchr(dest, ch); ch = i_getch(input); } o_addchr(dest, ch); if (ch == '`') { add_till_backquote(dest, input); o_addchr(dest, ch); continue; } //if (ch == '$') ... } } /* Process `cmd` - copy contents until "`" is seen. Complicated by * \` quoting. * "Within the backquoted style of command substitution, backslash * shall retain its literal meaning, except when followed by: '$', '`', or '\'. * The search for the matching backquote shall be satisfied by the first * backquote found without a preceding backslash; during this search, * if a non-escaped backquote is encountered within a shell comment, * a here-document, an embedded command substitution of the $(command) * form, or a quoted string, undefined results occur. A single-quoted * or double-quoted string that begins, but does not end, within the * "`...`" sequence produces undefined results." * Example Output * echo `echo '\'TEST\`echo ZZ\`BEST` \TESTZZBEST */ static void add_till_backquote(o_string *dest, struct in_str *input) { while (1) { int ch = i_getch(input); if (ch == EOF) { syntax_error_unterm_ch('`'); /*xfunc_die(); - redundant */ } if (ch == '`') return; if (ch == '\\') { /* \x. Copy both chars unless it is \` */ int ch2 = i_getch(input); if (ch2 == EOF) { syntax_error_unterm_ch('`'); /*xfunc_die(); - redundant */ } if (ch2 != '`' && ch2 != '$' && ch2 != '\\') o_addchr(dest, ch); ch = ch2; } o_addchr(dest, ch); } } /* Process $(cmd) - copy contents until ")" is seen. Complicated by * quoting and nested ()s. * "With the $(command) style of command substitution, all characters * following the open parenthesis to the matching closing parenthesis * constitute the command. Any valid shell script can be used for command, * except a script consisting solely of redirections which produces * unspecified results." * Example Output * echo $(echo '(TEST)' BEST) (TEST) BEST * echo $(echo 'TEST)' BEST) TEST) BEST * echo $(echo \(\(TEST\) BEST) ((TEST) BEST */ static void add_till_closing_paren(o_string *dest, struct in_str *input, bool dbl) { int count = 0; while (1) { int ch = i_getch(input); if (ch == EOF) { syntax_error_unterm_ch(')'); /*xfunc_die(); - redundant */ } if (ch == '(') count++; if (ch == ')') { if (--count < 0) { if (!dbl) break; if (i_peek(input) == ')') { i_getch(input); break; } } } o_addchr(dest, ch); if (ch == '\'') { add_till_single_quote(dest, input); o_addchr(dest, ch); continue; } if (ch == '"') { add_till_double_quote(dest, input); o_addchr(dest, ch); continue; } if (ch == '\\') { /* \x. Copy verbatim. Important for \(, \) */ ch = i_getch(input); if (ch == EOF) { syntax_error_unterm_ch(')'); /*xfunc_die(); - redundant */ } o_addchr(dest, ch); continue; } } } #endif /* ENABLE_HUSH_TICK || ENABLE_SH_MATH_SUPPORT */ /* Return code: 0 for OK, 1 for syntax error */ #if BB_MMU #define handle_dollar(as_string, dest, input) \ handle_dollar(dest, input) #endif static int handle_dollar(o_string *as_string, o_string *dest, struct in_str *input) { int ch = i_peek(input); /* first character after the $ */ unsigned char quote_mask = dest->o_escape ? 0x80 : 0; debug_printf_parse("handle_dollar entered: ch='%c'\n", ch); if (isalpha(ch)) { ch = i_getch(input); nommu_addchr(as_string, ch); make_var: o_addchr(dest, SPECIAL_VAR_SYMBOL); while (1) { debug_printf_parse(": '%c'\n", ch); o_addchr(dest, ch | quote_mask); quote_mask = 0; ch = i_peek(input); if (!isalnum(ch) && ch != '_') break; ch = i_getch(input); nommu_addchr(as_string, ch); } o_addchr(dest, SPECIAL_VAR_SYMBOL); } else if (isdigit(ch)) { make_one_char_var: ch = i_getch(input); nommu_addchr(as_string, ch); o_addchr(dest, SPECIAL_VAR_SYMBOL); debug_printf_parse(": '%c'\n", ch); o_addchr(dest, ch | quote_mask); o_addchr(dest, SPECIAL_VAR_SYMBOL); } else switch (ch) { case '$': /* pid */ case '!': /* last bg pid */ case '?': /* last exit code */ case '#': /* number of args */ case '*': /* args */ case '@': /* args */ goto make_one_char_var; case '{': { bool first_char, all_digits; int expansion; ch = i_getch(input); nommu_addchr(as_string, ch); o_addchr(dest, SPECIAL_VAR_SYMBOL); /* TODO: maybe someone will try to escape the '}' */ expansion = 0; first_char = true; all_digits = false; while (1) { ch = i_getch(input); nommu_addchr(as_string, ch); if (ch == '}') { break; } if (first_char) { if (ch == '#') { /* ${#var}: length of var contents */ goto char_ok; } if (isdigit(ch)) { all_digits = true; goto char_ok; } /* They're being verbose and doing ${?} */ if (i_peek(input) == '}' && strchr("$!?#*@_", ch)) goto char_ok; } if (expansion < 2 && ( (all_digits && !isdigit(ch)) || (!all_digits && !isalnum(ch) && ch != '_') ) ) { /* handle parameter expansions * http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html#tag_02_06_02 */ if (first_char) goto case_default; switch (ch) { case ':': /* null modifier */ if (expansion == 0) { debug_printf_parse(": null modifier\n"); ++expansion; break; } goto case_default; case '#': /* remove prefix */ case '%': /* remove suffix */ if (expansion == 0) { debug_printf_parse(": remove suffix/prefix\n"); expansion = 2; break; } goto case_default; case '-': /* default value */ case '=': /* assign default */ case '+': /* alternative */ case '?': /* error indicate */ debug_printf_parse(": parameter expansion\n"); expansion = 2; break; default: case_default: syntax_error_unterm_str("${name}"); debug_printf_parse("handle_dollar return 1: unterminated ${name}\n"); return 1; } } char_ok: debug_printf_parse(": '%c'\n", ch); o_addchr(dest, ch | quote_mask); quote_mask = 0; first_char = false; } /* while (1) */ o_addchr(dest, SPECIAL_VAR_SYMBOL); break; } #if ENABLE_SH_MATH_SUPPORT || ENABLE_HUSH_TICK case '(': { # if !BB_MMU int pos; # endif ch = i_getch(input); nommu_addchr(as_string, ch); # if ENABLE_SH_MATH_SUPPORT if (i_peek(input) == '(') { ch = i_getch(input); nommu_addchr(as_string, ch); o_addchr(dest, SPECIAL_VAR_SYMBOL); o_addchr(dest, /*quote_mask |*/ '+'); # if !BB_MMU pos = dest->length; # endif add_till_closing_paren(dest, input, true); # if !BB_MMU if (as_string) { o_addstr(as_string, dest->data + pos); o_addchr(as_string, ')'); o_addchr(as_string, ')'); } # endif o_addchr(dest, SPECIAL_VAR_SYMBOL); break; } # endif # if ENABLE_HUSH_TICK o_addchr(dest, SPECIAL_VAR_SYMBOL); o_addchr(dest, quote_mask | '`'); # if !BB_MMU pos = dest->length; # endif add_till_closing_paren(dest, input, false); # if !BB_MMU if (as_string) { o_addstr(as_string, dest->data + pos); o_addchr(as_string, ')'); } # endif o_addchr(dest, SPECIAL_VAR_SYMBOL); # endif break; } #endif case '_': ch = i_getch(input); nommu_addchr(as_string, ch); ch = i_peek(input); if (isalnum(ch)) { /* it's $_name or $_123 */ ch = '_'; goto make_var; } /* else: it's $_ */ /* TODO: $_ and $-: */ /* $_ Shell or shell script name; or last argument of last command * (if last command wasn't a pipe; if it was, bash sets $_ to ""); * but in command's env, set to full pathname used to invoke it */ /* $- Option flags set by set builtin or shell options (-i etc) */ default: o_addQchr(dest, '$'); } debug_printf_parse("handle_dollar return 0\n"); return 0; } #if BB_MMU #define parse_stream_dquoted(as_string, dest, input, dquote_end) \ parse_stream_dquoted(dest, input, dquote_end) #endif static int parse_stream_dquoted(o_string *as_string, o_string *dest, struct in_str *input, int dquote_end) { int ch; int next; again: ch = i_getch(input); if (ch != EOF) nommu_addchr(as_string, ch); if (ch == dquote_end) { /* may be only '"' or EOF */ if (dest->o_assignment == NOT_ASSIGNMENT) dest->o_escape ^= 1; debug_printf_parse("parse_stream_dquoted return 0\n"); return 0; } /* note: can't move it above ch == dquote_end check! */ if (ch == EOF) { syntax_error_unterm_ch('"'); /*xfunc_die(); - redundant */ } next = '\0'; if (ch != '\n') { next = i_peek(input); } debug_printf_parse("\" ch=%c (%d) escape=%d\n", ch, ch, dest->o_escape); if (ch == '\\') { if (next == EOF) { syntax_error("\\"); xfunc_die(); } /* bash: * "The backslash retains its special meaning [in "..."] * only when followed by one of the following characters: * $, `, ", \, or . A double quote may be quoted * within double quotes by preceding it with a backslash." */ if (strchr("$`\"\\\n", next) != NULL) { ch = i_getch(input); if (ch != '\n') { o_addqchr(dest, ch); nommu_addchr(as_string, ch); } } else { o_addqchr(dest, '\\'); nommu_addchr(as_string, '\\'); } goto again; } if (ch == '$') { if (handle_dollar(as_string, dest, input) != 0) { debug_printf_parse("parse_stream_dquoted return 1: " "handle_dollar returned non-0\n"); return 1; } goto again; } #if ENABLE_HUSH_TICK if (ch == '`') { //int pos = dest->length; o_addchr(dest, SPECIAL_VAR_SYMBOL); o_addchr(dest, 0x80 | '`'); add_till_backquote(dest, input); o_addchr(dest, SPECIAL_VAR_SYMBOL); //debug_printf_subst("SUBST RES3 '%s'\n", dest->data + pos); goto again; } #endif o_addQchr(dest, ch); if (ch == '=' && (dest->o_assignment == MAYBE_ASSIGNMENT || dest->o_assignment == WORD_IS_KEYWORD) && is_well_formed_var_name(dest->data, '=') ) { dest->o_assignment = DEFINITELY_ASSIGNMENT; } goto again; } /* * Scan input until EOF or end_trigger char. * Return a list of pipes to execute, or NULL on EOF * or if end_trigger character is met. * On syntax error, exit is shell is not interactive, * reset parsing machinery and start parsing anew, * or return ERR_PTR. */ static struct pipe *parse_stream(char **pstring, struct in_str *input, int end_trigger) { struct parse_context ctx; o_string dest = NULL_O_STRING; int is_in_dquote; int heredoc_cnt; /* Double-quote state is handled in the state variable is_in_dquote. * A single-quote triggers a bypass of the main loop until its mate is * found. When recursing, quote state is passed in via dest->o_escape. */ debug_printf_parse("parse_stream entered, end_trigger='%c'\n", end_trigger ? end_trigger : 'X'); debug_enter(); /* If very first arg is "" or '', dest.data may end up NULL. * Preventing this: */ o_addchr(&dest, '\0'); dest.length = 0; G.ifs = get_local_var_value("IFS"); if (G.ifs == NULL) G.ifs = defifs; reset: #if ENABLE_HUSH_INTERACTIVE input->promptmode = 0; /* PS1 */ #endif /* dest.o_assignment = MAYBE_ASSIGNMENT; - already is */ initialize_context(&ctx); is_in_dquote = 0; heredoc_cnt = 0; while (1) { const char *is_ifs; const char *is_special; int ch; int next; int redir_fd; redir_type redir_style; if (is_in_dquote) { /* dest.o_quoted = 1; - already is (see below) */ if (parse_stream_dquoted(&ctx.as_string, &dest, input, '"')) { goto parse_error; } /* We reached closing '"' */ is_in_dquote = 0; } ch = i_getch(input); debug_printf_parse(": ch=%c (%d) escape=%d\n", ch, ch, dest.o_escape); if (ch == EOF) { struct pipe *pi; if (heredoc_cnt) { syntax_error_unterm_str("here document"); goto parse_error; } /* end_trigger == '}' case errors out earlier, * checking only ')' */ if (end_trigger == ')') { syntax_error_unterm_ch('('); /* exits */ /* goto parse_error; */ } if (done_word(&dest, &ctx)) { goto parse_error; } o_free(&dest); done_pipe(&ctx, PIPE_SEQ); pi = ctx.list_head; /* If we got nothing... */ /* (this makes bare "&" cmd a no-op. * bash says: "syntax error near unexpected token '&'") */ if (pi->num_cmds == 0 IF_HAS_KEYWORDS( && pi->res_word == RES_NONE) ) { free_pipe_list(pi); pi = NULL; } #if !BB_MMU debug_printf_parse("as_string '%s'\n", ctx.as_string.data); if (pstring) *pstring = ctx.as_string.data; else o_free_unsafe(&ctx.as_string); #endif debug_leave(); debug_printf_parse("parse_stream return %p\n", pi); return pi; } nommu_addchr(&ctx.as_string, ch); next = '\0'; if (ch != '\n') next = i_peek(input); is_special = "{}<>;&|()#'" /* special outside of "str" */ "\\$\"" IF_HUSH_TICK("`"); /* always special */ /* Are { and } special here? */ if (ctx.command->argv /* word [word]{... */ || dest.length /* word{... */ || dest.o_quoted /* ""{... */ || (next != ';' && next != ')' && !strchr(G.ifs, next)) /* {word */ ) { /* They are not special, skip "{}" */ is_special += 2; } is_special = strchr(is_special, ch); is_ifs = strchr(G.ifs, ch); if (!is_special && !is_ifs) { /* ordinary char */ ordinary_char: o_addQchr(&dest, ch); if ((dest.o_assignment == MAYBE_ASSIGNMENT || dest.o_assignment == WORD_IS_KEYWORD) && ch == '=' && is_well_formed_var_name(dest.data, '=') ) { dest.o_assignment = DEFINITELY_ASSIGNMENT; } continue; } if (is_ifs) { if (done_word(&dest, &ctx)) { goto parse_error; } if (ch == '\n') { #if ENABLE_HUSH_CASE /* "case ... in word) ..." - * newlines are ignored (but ';' wouldn't be) */ if (ctx.command->argv == NULL && ctx.ctx_res_w == RES_MATCH ) { continue; } #endif /* Treat newline as a command separator. */ done_pipe(&ctx, PIPE_SEQ); debug_printf_parse("heredoc_cnt:%d\n", heredoc_cnt); if (heredoc_cnt) { if (fetch_heredocs(heredoc_cnt, &ctx, input)) { goto parse_error; } heredoc_cnt = 0; } dest.o_assignment = MAYBE_ASSIGNMENT; ch = ';'; /* note: if (is_ifs) continue; * will still trigger for us */ } } /* "cmd}" or "cmd }..." without semicolon or &: * } is an ordinary char in this case, even inside { cmd; } * Pathological example: { ""}; } should exec "}" cmd */ if (ch == '}') { if (!IS_NULL_CMD(ctx.command) /* cmd } */ || dest.length != 0 /* word} */ || dest.o_quoted /* ""} */ ) { goto ordinary_char; } if (!IS_NULL_PIPE(ctx.pipe)) /* cmd | } */ goto skip_end_trigger; /* else: } does terminate a group */ } if (end_trigger && end_trigger == ch && (ch != ';' || heredoc_cnt == 0) #if ENABLE_HUSH_CASE && (ch != ')' || ctx.ctx_res_w != RES_MATCH || (!dest.o_quoted && strcmp(dest.data, "esac") == 0) ) #endif ) { if (heredoc_cnt) { /* This is technically valid: * { cat < before deciding whether this word is * an assignment. a=1 2>z b=2: b=2 is still assignment */ switch (ch) { case '>': redir_fd = redirect_opt_num(&dest); if (done_word(&dest, &ctx)) { goto parse_error; } redir_style = REDIRECT_OVERWRITE; if (next == '>') { redir_style = REDIRECT_APPEND; ch = i_getch(input); nommu_addchr(&ctx.as_string, ch); } #if 0 else if (next == '(') { syntax_error(">(process) not supported"); goto parse_error; } #endif if (parse_redirect(&ctx, redir_fd, redir_style, input)) goto parse_error; continue; /* back to top of while (1) */ case '<': redir_fd = redirect_opt_num(&dest); if (done_word(&dest, &ctx)) { goto parse_error; } redir_style = REDIRECT_INPUT; if (next == '<') { redir_style = REDIRECT_HEREDOC; heredoc_cnt++; debug_printf_parse("++heredoc_cnt=%d\n", heredoc_cnt); ch = i_getch(input); nommu_addchr(&ctx.as_string, ch); } else if (next == '>') { redir_style = REDIRECT_IO; ch = i_getch(input); nommu_addchr(&ctx.as_string, ch); } #if 0 else if (next == '(') { syntax_error("<(process) not supported"); goto parse_error; } #endif if (parse_redirect(&ctx, redir_fd, redir_style, input)) goto parse_error; continue; /* back to top of while (1) */ } if (dest.o_assignment == MAYBE_ASSIGNMENT /* check that we are not in word in "a=1 2>word b=1": */ && !ctx.pending_redirect ) { /* ch is a special char and thus this word * cannot be an assignment */ dest.o_assignment = NOT_ASSIGNMENT; } /* Note: nommu_addchr(&ctx.as_string, ch) is already done */ switch (ch) { case '#': if (dest.length == 0) { while (1) { ch = i_peek(input); if (ch == EOF || ch == '\n') break; i_getch(input); /* note: we do not add it to &ctx.as_string */ } nommu_addchr(&ctx.as_string, '\n'); } else { o_addQchr(&dest, ch); } break; case '\\': if (next == EOF) { syntax_error("\\"); xfunc_die(); } ch = i_getch(input); if (ch != '\n') { o_addchr(&dest, '\\'); /*nommu_addchr(&ctx.as_string, '\\'); - already done */ o_addchr(&dest, ch); nommu_addchr(&ctx.as_string, ch); /* Example: echo Hello \2>file * we need to know that word 2 is quoted */ dest.o_quoted = 1; } #if !BB_MMU else { /* It's "\". Remove trailing '\' from ctx.as_string */ ctx.as_string.data[--ctx.as_string.length] = '\0'; } #endif break; case '$': if (handle_dollar(&ctx.as_string, &dest, input) != 0) { debug_printf_parse("parse_stream parse error: " "handle_dollar returned non-0\n"); goto parse_error; } break; case '\'': dest.o_quoted = 1; while (1) { ch = i_getch(input); if (ch == EOF) { syntax_error_unterm_ch('\''); /*xfunc_die(); - redundant */ } nommu_addchr(&ctx.as_string, ch); if (ch == '\'') break; o_addqchr(&dest, ch); } break; case '"': dest.o_quoted = 1; is_in_dquote ^= 1; /* invert */ if (dest.o_assignment == NOT_ASSIGNMENT) dest.o_escape ^= 1; break; #if ENABLE_HUSH_TICK case '`': { #if !BB_MMU int pos; #endif o_addchr(&dest, SPECIAL_VAR_SYMBOL); o_addchr(&dest, '`'); #if !BB_MMU pos = dest.length; #endif add_till_backquote(&dest, input); #if !BB_MMU o_addstr(&ctx.as_string, dest.data + pos); o_addchr(&ctx.as_string, '`'); #endif o_addchr(&dest, SPECIAL_VAR_SYMBOL); //debug_printf_subst("SUBST RES3 '%s'\n", dest.data + pos); break; } #endif case ';': #if ENABLE_HUSH_CASE case_semi: #endif if (done_word(&dest, &ctx)) { goto parse_error; } done_pipe(&ctx, PIPE_SEQ); #if ENABLE_HUSH_CASE /* Eat multiple semicolons, detect * whether it means something special */ while (1) { ch = i_peek(input); if (ch != ';') break; ch = i_getch(input); nommu_addchr(&ctx.as_string, ch); if (ctx.ctx_res_w == RES_CASE_BODY) { ctx.ctx_dsemicolon = 1; ctx.ctx_res_w = RES_MATCH; break; } } #endif new_cmd: /* We just finished a cmd. New one may start * with an assignment */ dest.o_assignment = MAYBE_ASSIGNMENT; break; case '&': if (done_word(&dest, &ctx)) { goto parse_error; } if (next == '&') { ch = i_getch(input); nommu_addchr(&ctx.as_string, ch); done_pipe(&ctx, PIPE_AND); } else { done_pipe(&ctx, PIPE_BG); } goto new_cmd; case '|': if (done_word(&dest, &ctx)) { goto parse_error; } #if ENABLE_HUSH_CASE if (ctx.ctx_res_w == RES_MATCH) break; /* we are in case's "word | word)" */ #endif if (next == '|') { /* || */ ch = i_getch(input); nommu_addchr(&ctx.as_string, ch); done_pipe(&ctx, PIPE_OR); } else { /* we could pick up a file descriptor choice here * with redirect_opt_num(), but bash doesn't do it. * "echo foo 2| cat" yields "foo 2". */ done_command(&ctx); #if !BB_MMU o_reset_to_empty_unquoted(&ctx.as_string); #endif } goto new_cmd; case '(': #if ENABLE_HUSH_CASE /* "case... in [(]word)..." - skip '(' */ if (ctx.ctx_res_w == RES_MATCH && ctx.command->argv == NULL /* not (word|(... */ && dest.length == 0 /* not word(... */ && dest.o_quoted == 0 /* not ""(... */ ) { continue; } #endif case '{': if (parse_group(&dest, &ctx, input, ch) != 0) { goto parse_error; } goto new_cmd; case ')': #if ENABLE_HUSH_CASE if (ctx.ctx_res_w == RES_MATCH) goto case_semi; #endif case '}': /* proper use of this character is caught by end_trigger: * if we see {, we call parse_group(..., end_trigger='}') * and it will match } earlier (not here). */ syntax_error_unexpected_ch(ch); goto parse_error; default: if (HUSH_DEBUG) bb_error_msg_and_die("BUG: unexpected %c\n", ch); } } /* while (1) */ parse_error: { struct parse_context *pctx; IF_HAS_KEYWORDS(struct parse_context *p2;) /* Clean up allocated tree. * Sample for finding leaks on syntax error recovery path. * Run it from interactive shell, watch pmap `pidof hush`. * while if false; then false; fi; do break; fi * Samples to catch leaks at execution: * while if (true | {true;}); then echo ok; fi; do break; done * while if (true | {true;}); then echo ok; fi; do (if echo ok; break; then :; fi) | cat; break; done */ pctx = &ctx; do { /* Update pipe/command counts, * otherwise freeing may miss some */ done_pipe(pctx, PIPE_SEQ); debug_printf_clean("freeing list %p from ctx %p\n", pctx->list_head, pctx); debug_print_tree(pctx->list_head, 0); free_pipe_list(pctx->list_head); debug_printf_clean("freed list %p\n", pctx->list_head); #if !BB_MMU o_free_unsafe(&pctx->as_string); #endif IF_HAS_KEYWORDS(p2 = pctx->stack;) if (pctx != &ctx) { free(pctx); } IF_HAS_KEYWORDS(pctx = p2;) } while (HAS_KEYWORDS && pctx); /* Free text, clear all dest fields */ o_free(&dest); /* If we are not in top-level parse, we return, * our caller will propagate error. */ if (end_trigger != ';') { #if !BB_MMU if (pstring) *pstring = NULL; #endif debug_leave(); return ERR_PTR; } /* Discard cached input, force prompt */ input->p = NULL; IF_HUSH_INTERACTIVE(input->promptme = 1;) goto reset; } } /* Executing from string: eval, sh -c '...' * or from file: /etc/profile, . file, sh