diff options
| -rw-r--r-- | shell/hush.c | 171 | ||||
| -rw-r--r-- | shell/hush_doc.txt | 13 |
2 files changed, 107 insertions, 77 deletions
diff --git a/shell/hush.c b/shell/hush.c index ca2a1d21f..21cb36564 100644 --- a/shell/hush.c +++ b/shell/hush.c @@ -54,7 +54,7 @@ * to-do: * port selected bugfixes from post-0.49 busybox lash - done? * change { and } from special chars to reserved words - * builtins: break, continue, eval, return, set, trap, ulimit + * builtins: return, trap, ulimit * test magic exec * check setting of global_argc and global_argv * follow IFS rules more precisely, including update semantics @@ -74,6 +74,7 @@ #include <fnmatch.h> #endif +#define HUSH_VER_STR "0.9" #if !BB_MMU && ENABLE_HUSH_TICK //#undef ENABLE_HUSH_TICK @@ -230,7 +231,7 @@ void xxfree(void *ptr) #define SPECIAL_VAR_SYMBOL 3 #define PARSEFLAG_EXIT_FROM_LOOP 1 -typedef enum { +typedef enum redir_type { REDIRECT_INPUT = 1, REDIRECT_OVERWRITE = 2, REDIRECT_APPEND = 3, @@ -253,14 +254,14 @@ static const struct { { O_RDWR, 1, "<>" } }; -typedef enum { +typedef enum pipe_style { PIPE_SEQ = 1, PIPE_AND = 2, PIPE_OR = 3, PIPE_BG = 4, } pipe_style; -typedef enum { +typedef enum reserved_style { RES_NONE = 0, #if ENABLE_HUSH_IF RES_IF , @@ -358,7 +359,7 @@ struct variable { smallint flg_read_only; }; -typedef struct { +typedef struct o_string { char *data; int length; /* position where data is appended */ int maxlen; @@ -378,9 +379,9 @@ enum { /* Used for initialization: o_string foo = NULL_O_STRING; */ #define NULL_O_STRING { NULL } -/* I can almost use ordinary FILE *. Is open_memstream() universally +/* I can almost use ordinary FILE*. Is open_memstream() universally * available? Where is it documented? */ -struct in_str { +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 */ @@ -392,7 +393,7 @@ struct in_str { FILE *file; int (*get) (struct in_str *); int (*peek) (struct in_str *); -}; +} in_str; #define i_getch(input) ((input)->get(input)) #define i_peek(input) ((input)->peek(input)) @@ -403,7 +404,11 @@ enum { CHAR_SPECIAL = 3, /* example: $ */ }; -#define HUSH_VER_STR "0.02" +enum { + BC_BREAK = 1, + BC_CONTINUE = 2, +}; + /* "Globals" within this file */ @@ -429,6 +434,7 @@ struct globals { struct pipe *toplevel_list; smallint ctrl_z_flag; #endif + smallint flag_break_continue; smallint fake_mode; /* these three support $?, $#, and $1 */ smalluint last_return_code; @@ -481,6 +487,7 @@ enum { run_list_level = 0 }; #define global_argc (G.global_argc ) #define last_return_code (G.last_return_code) #define ifs (G.ifs ) +#define flag_break_continue (G.flag_break_continue) #define fake_mode (G.fake_mode ) #define cwd (G.cwd ) #define last_bg_pid (G.last_bg_pid ) @@ -713,6 +720,8 @@ static int builtin_shift(char **argv); static int builtin_source(char **argv); static int builtin_umask(char **argv); static int builtin_unset(char **argv); +static int builtin_break(char **argv); +static int builtin_continue(char **argv); //static int builtin_not_written(char **argv); /* Table of built-in functions. They can be forked or not, depending on @@ -742,10 +751,10 @@ static const struct built_in_command bltins[] = { #if ENABLE_HUSH_JOB BLTIN("bg" , builtin_fg_bg, "Resume a job in the background"), #endif -// BLTIN("break" , builtin_not_written, "Exit for, while or until loop"), + BLTIN("break" , builtin_break, "Exit from a loop"), BLTIN("cd" , builtin_cd, "Change directory"), -// BLTIN("continue", builtin_not_written, "Continue for, while or until loop"), - BLTIN("echo" , builtin_echo, "Write strings to stdout"), + BLTIN("continue", builtin_continue, "Start new loop iteration"), + BLTIN("echo" , builtin_echo, "Write to stdout"), 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"), @@ -2016,29 +2025,25 @@ static int run_list(struct pipe *pi) char *case_word = NULL; #endif #if ENABLE_HUSH_LOOPS - struct pipe *loop_top = loop_top; /* just for compiler */ + struct pipe *loop_top = NULL; char *for_varname = NULL; char **for_lcur = NULL; char **for_list = NULL; - smallint flag_run_loop = 0; - smallint flag_goto_looptop = 0; #endif smallint flag_skip = 1; smalluint rcode = 0; /* probably just for compiler */ #if ENABLE_HUSH_IF smalluint cond_code = 0; -///experimentally off: last_cond_code seems to be bogus - ///smalluint last_cond_code = 0; /* need double-buffer to handle "elif" */ #else - enum { cond_code = 0, /* ///last_cond_code = 0 */ }; + enum { cond_code = 0, }; #endif - /*reserved_style*/ smallint rword IF_HAS_NO_KEYWORDS(= RES_NONE); - /*reserved_style*/ smallint skip_more_for_this_rword = RES_XXXX; + /*enum reserved_style*/ smallint rword = RES_NONE; + /*enum reserved_style*/ smallint skip_more_for_this_rword = RES_XXXX; debug_printf_exec("run_list start lvl %d\n", run_list_level + 1); #if ENABLE_HUSH_LOOPS - /* check syntax for "for" */ + /* 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; @@ -2108,20 +2113,16 @@ static int run_list(struct pipe *pi) } #endif /* JOB */ - /* Go through list of pipes, (maybe) executing them */ - for (; pi; pi = USE_HUSH_LOOPS( flag_goto_looptop ? loop_top : ) pi->next) { + /* Go through list of pipes, (maybe) executing them. */ + for (; pi; pi = USE_HUSH_LOOPS(rword == RES_DONE ? loop_top : ) pi->next) { IF_HAS_KEYWORDS(rword = pi->res_word;) IF_HAS_NO_KEYWORDS(rword = RES_NONE;) - debug_printf_exec(": rword=%d cond_code=%d last_cond_code=%d skip_more=%d flag_run_loop=%d\n", - rword, cond_code, last_cond_code, skip_more_for_this_rword, flag_run_loop); + debug_printf_exec(": rword=%d cond_code=%d skip_more=%d\n", + rword, cond_code, skip_more_for_this_rword); #if ENABLE_HUSH_LOOPS if (rword == RES_WHILE || rword == RES_UNTIL || rword == RES_FOR) { - /* start of a loop: remember it */ - flag_goto_looptop = 0; /* not yet reached final "done" */ -// if (!loop_top) { /* hmm why this check is needed? */ -// flag_run_loop = 0; /* suppose loop condition is false (for now) */ - loop_top = pi; /* remember where loop starts */ -// } + /* start of a loop: remember where loop starts */ + loop_top = pi; } #endif if (rword == skip_more_for_this_rword && flag_skip) { @@ -2134,18 +2135,21 @@ static int run_list(struct pipe *pi) flag_skip = 1; skip_more_for_this_rword = RES_XXXX; #if ENABLE_HUSH_IF -/// if (rword == RES_THEN) // || rword == RES_ELSE) -/// cond_code = last_cond_code; - if (rword == RES_THEN && cond_code) - continue; /* "if <false> THEN cmd": skip cmd */ - if (rword == RES_ELSE && !cond_code) - //continue; /* "if <true> then ... ELSE cmd": skip cmd */ - break; //TEST - if (rword == RES_ELIF && !cond_code) - break; /* "if <true> then ... ELIF cmd": skip cmd and all following ones */ + if (cond_code) { + if (rword == RES_THEN) { + /* "if <false> THEN cmd": skip cmd */ + continue; + } + } else { + if (rword == RES_ELSE || rword == RES_ELIF) { + /* "if <true> then ... ELSE/ELIF cmd": + * skip cmd and all following ones */ + break; + } + } #endif #if ENABLE_HUSH_LOOPS - if (rword == RES_FOR && pi->num_progs) { /* hmm why "&& pi->num_progs"? */ + if (rword == RES_FOR) { /* && pi->num_progs - always == 1 */ if (!for_lcur) { /* first loop through for */ @@ -2161,7 +2165,7 @@ static int run_list(struct pipe *pi) if (pi->next->res_word == RES_IN) { /* if no variable values after "in" we skip "for" */ if (!pi->next->progs->argv) - continue; + break; vals = pi->next->progs->argv; } /* else: "for var; do..." -> assume "$@" list */ /* create list of variable values */ @@ -2171,7 +2175,6 @@ static int run_list(struct pipe *pi) debug_print_strings("for_list", for_list); for_varname = pi->progs->argv[0]; pi->progs->argv[0] = NULL; - flag_run_loop = 1; /* "for" has no loop condition, loop... */ } free(pi->progs->argv[0]); if (!*for_lcur) { @@ -2179,33 +2182,22 @@ static int run_list(struct pipe *pi) free(for_list); for_list = NULL; for_lcur = NULL; - flag_run_loop = 0; /* ... until end of value list */ pi->progs->argv[0] = for_varname; - continue; + break; } /* insert next value from for_lcur */ //TODO: does it need escaping? pi->progs->argv[0] = xasprintf("%s=%s", for_varname, *for_lcur++); } - if (rword == RES_IN) /* "for v IN list; do ..." - no pipe to execute here */ + if (rword == RES_IN) /* "for v IN list;..." - "in" has no cmds anyway */ continue; - if (rword == RES_DO) { /* "...; DO cmd; cmd" - this pipe is in loop body */ - if (!flag_run_loop) - continue; /* we are skipping this iteration */ - } - if (rword == RES_DONE) { /* end of loop? */ - if (flag_run_loop) { - flag_goto_looptop = 1; -// } else { -// loop_top = NULL; - } - continue; //TEST /* "done" has no cmd 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->progs->argv); - //bb_error_msg("case: arg:'%s' case_word:'%s'", pi->progs->argv[0], case_word); continue; } if (rword == RES_MATCH) { @@ -2215,35 +2207,53 @@ static int run_list(struct pipe *pi) /* all prev words didn't match, does this one match? */ pattern = expand_strvec_to_string(pi->progs->argv); /* TODO: which FNM_xxx flags to use? */ - /* ///last_ */ cond_code = (fnmatch(pattern, case_word, /*flags:*/ 0) != 0); - //bb_error_msg("fnmatch('%s','%s'):%d", pattern, case_word, cond_code); + cond_code = (fnmatch(pattern, case_word, /*flags:*/ 0) != 0); free(pattern); - if (/* ///last_ */ cond_code == 0) { /* match! we will execute this branch */ + if (cond_code == 0) { /* match! we will execute this branch */ free(case_word); /* make future "word)" stop */ case_word = NULL; } continue; } if (rword == RES_CASEI) { /* inside of a case branch */ - if (/* ///last_ */ cond_code != 0) + if (cond_code != 0) continue; /* not matched yet, skip this pipe */ } #endif if (pi->num_progs == 0) continue; - /* After analyzing all keywrds and conditions, we decided - * to execute this pipe */ + /* After analyzing all keywords and conditions, we decided + * to execute this pipe. NB: has 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_progs); { int r; + flag_break_continue = 0; rcode = r = run_pipe(pi); /* NB: rcode is a smallint */ if (r != -1) { - /* We only ran a builtin: rcode was set by the return value - * of run_pipe(), and we don't need to wait for anything. */ + /* we only ran a builtin: rcode is already known + * and we don't need to wait for anything. */ + /* was it "break" or "continue"? */ + if (flag_break_continue) { + smallint fbc = flag_break_continue; + /* we might fall into outer *loop*, + * don't want to break it too */ + flag_break_continue = 0; + if (loop_top) { + if (fbc == BC_BREAK) + goto check_jobs_and_break; + /* "continue": simulate end of loop */ + rword = RES_DONE; + continue; + } + bb_error_msg("break/continue: only meaningful in a loop"); + /* bash compat: exit code is still 0 */ + } } 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: + /* 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 */ #if ENABLE_HUSH_JOB @@ -2271,16 +2281,19 @@ static int run_list(struct pipe *pi) /* Analyze how result affects subsequent commands */ #if ENABLE_HUSH_IF if (rword == RES_IF || rword == RES_ELIF) - /* ///last_cond_code = */ cond_code = rcode; + cond_code = rcode; #endif #if ENABLE_HUSH_LOOPS if (rword == RES_WHILE) { - flag_run_loop = !rcode; - debug_printf_exec(": setting flag_run_loop=%d\n", flag_run_loop); + if (rcode) + goto check_jobs_and_break; } if (rword == RES_UNTIL) { - flag_run_loop = rcode; - debug_printf_exec(": setting flag_run_loop=%d\n", flag_run_loop); + if (!rcode) { + check_jobs_and_break: + checkjobs(NULL); + break; + } } #endif if ((rcode == 0 && pi->followup == PIPE_OR) @@ -4498,3 +4511,15 @@ static int builtin_unset(char **argv) unset_local_var(argv[1]); return EXIT_SUCCESS; } + +static int builtin_break(char **argv UNUSED_PARAM) +{ + flag_break_continue = BC_BREAK; + return EXIT_SUCCESS; +} + +static int builtin_continue(char **argv UNUSED_PARAM) +{ + flag_break_continue = BC_CONTINUE; + return EXIT_SUCCESS; +} diff --git a/shell/hush_doc.txt b/shell/hush_doc.txt index 39f7dcee5..c68dc2416 100644 --- a/shell/hush_doc.txt +++ b/shell/hush_doc.txt @@ -2,9 +2,10 @@ Command parsing -Command parsing results in "pipe" structures. "Pipe" structure -does not always correspond to what sh language calls "pipe", -it also controls execution of if, while, etc statements. +Command parsing results in a list of "pipe" structures. +This list correspond not only to usual "pipe1 || pipe2 && pipe3" +lists, but it also controls execution of if, while, etc statements. +Every such statement is a list for hush. List consists of pipes. struct pipe fields: smallint res_word - "none" for normal commands, @@ -18,7 +19,7 @@ Blocks of commands { pipe; pipe; } and (pipe; pipe) are represented as one pipe struct with one progs[0] element which is a "group" - struct child_prog can contain a list of pipes. Sometimes these "groups" are created implicitly, e.g. every control -statement (if, while, etc) sits inside its own "pipe" struct). +statement (if, while, etc) sits inside its own group. res_word controls statement execution. Examples: @@ -41,6 +42,10 @@ res_word=NONE followup=SEQ pipe 4 res_word=NONE followup=(null) pipe 1 res_word=NONE followup=SEQ +Above you see that if is a list, and it sits in a {} group +implicitly created by hush. Also note two THEN res_word's - +it is explained below. + "if true; then { echo Hello; true; }; fi" - pipe 0 res_word=NONE followup=SEQ prog 0 group {}: |