/* vi: set sw=4 ts=4: */ /* * Mini xargs implementation for busybox * * (C) 2002,2003 by Vladimir Oleynik <dzo@simtreas.ru> * * Special thanks * - Mark Whitley and Glenn McGrath for stimulus to rewrite :) * - Mike Rendell <michael@cs.mun.ca> * and David MacKenzie <djm@gnu.ai.mit.edu>. * * Licensed under GPLv2 or later, see file LICENSE in this source tree. * * xargs is described in the Single Unix Specification v3 at * http://www.opengroup.org/onlinepubs/007904975/utilities/xargs.html */ //config:config XARGS //config: bool "xargs" //config: default y //config: help //config: xargs is used to execute a specified command for //config: every item from standard input. //config: //config:config FEATURE_XARGS_SUPPORT_CONFIRMATION //config: bool "Enable -p: prompt and confirmation" //config: default y //config: depends on XARGS //config: help //config: Support -p: prompt the user whether to run each command //config: line and read a line from the terminal. //config: //config:config FEATURE_XARGS_SUPPORT_QUOTES //config: bool "Enable single and double quotes and backslash" //config: default y //config: depends on XARGS //config: help //config: Support quoting in the input. //config: //config:config FEATURE_XARGS_SUPPORT_TERMOPT //config: bool "Enable -x: exit if -s or -n is exceeded" //config: default y //config: depends on XARGS //config: help //config: Support -x: exit if the command size (see the -s or -n option) //config: is exceeded. //config: //config:config FEATURE_XARGS_SUPPORT_ZERO_TERM //config: bool "Enable -0: NUL-terminated input" //config: default y //config: depends on XARGS //config: help //config: Support -0: input items are terminated by a NUL character //config: instead of whitespace, and the quotes and backslash //config: are not special. //applet:IF_XARGS(APPLET_NOEXEC(xargs, xargs, BB_DIR_USR_BIN, BB_SUID_DROP, xargs)) //kbuild:lib-$(CONFIG_XARGS) += xargs.o #include "libbb.h" /* This is a NOEXEC applet. Be very careful! */ //#define dbg_msg(...) bb_error_msg(__VA_ARGS__) #define dbg_msg(...) ((void)0) #ifdef TEST # ifndef ENABLE_FEATURE_XARGS_SUPPORT_CONFIRMATION # define ENABLE_FEATURE_XARGS_SUPPORT_CONFIRMATION 1 # endif # ifndef ENABLE_FEATURE_XARGS_SUPPORT_QUOTES # define ENABLE_FEATURE_XARGS_SUPPORT_QUOTES 1 # endif # ifndef ENABLE_FEATURE_XARGS_SUPPORT_TERMOPT # define ENABLE_FEATURE_XARGS_SUPPORT_TERMOPT 1 # endif # ifndef ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM # define ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM 1 # endif #endif struct globals { char **args; const char *eof_str; int idx; } FIX_ALIASING; #define G (*(struct globals*)&bb_common_bufsiz1) #define INIT_G() do { \ G.eof_str = NULL; /* need to clear by hand because we are NOEXEC applet */ \ } while (0) /* * This function has special algorithm. * Don't use fork and include to main! */ static int xargs_exec(void) { int status; status = spawn_and_wait(G.args); if (status < 0) { bb_simple_perror_msg(G.args[0]); return errno == ENOENT ? 127 : 126; } if (status == 255) { bb_error_msg("%s: exited with status 255; aborting", G.args[0]); return 124; } if (status >= 0x180) { bb_error_msg("%s: terminated by signal %d", G.args[0], status - 0x180); return 125; } if (status) return 123; return 0; } /* In POSIX/C locale isspace is only these chars: "\t\n\v\f\r" and space. * "\t\n\v\f\r" happen to have ASCII codes 9,10,11,12,13. */ #define ISSPACE(a) ({ unsigned char xargs__isspace = (a) - 9; xargs__isspace == (' ' - 9) || xargs__isspace <= (13 - 9); }) static void store_param(char *s) { /* Grow by 256 elements at once */ if (!(G.idx & 0xff)) { /* G.idx == N*256 */ /* Enlarge, make G.args[(N+1)*256 - 1] last valid idx */ G.args = xrealloc(G.args, sizeof(G.args[0]) * (G.idx + 0x100)); } G.args[G.idx++] = s; } /* process[0]_stdin: * Read characters into buf[n_max_chars+1], and when parameter delimiter * is seen, store the address of a new parameter to args[]. * If reading discovers that last chars do not form the complete * parameter, the pointer to the first such "tail character" is returned. * (buf has extra byte at the end to accomodate terminating NUL * of "tail characters" string). * Otherwise, the returned pointer points to NUL byte. * On entry, buf[] may contain some "seed chars" which are to become * the beginning of the first parameter. */ #if ENABLE_FEATURE_XARGS_SUPPORT_QUOTES static char* FAST_FUNC process_stdin(int n_max_chars, int n_max_arg, char *buf) { #define NORM 0 #define QUOTE 1 #define BACKSLASH 2 #define SPACE 4 char q = '\0'; /* quote char */ char state = NORM; char *s = buf; /* start of the word */ char *p = s + strlen(buf); /* end of the word */ buf += n_max_chars; /* past buffer's end */ /* "goto ret" is used instead of "break" to make control flow * more obvious: */ while (1) { int c = getchar(); if (c == EOF) { if (p != s) goto close_word; goto ret; } if (state == BACKSLASH) { state = NORM; goto set; } if (state == QUOTE) { if (c != q) goto set; q = '\0'; state = NORM; } else { /* if (state == NORM) */ if (ISSPACE(c)) { if (p != s) { close_word: state = SPACE; c = '\0'; goto set; } } else { if (c == '\\') { state = BACKSLASH; } else if (c == '\'' || c == '"') { q = c; state = QUOTE; } else { set: *p++ = c; } } } if (state == SPACE) { /* word's delimiter or EOF detected */ if (q) { bb_error_msg_and_die("unmatched %s quote", q == '\'' ? "single" : "double"); } /* A full word is loaded */ if (G.eof_str) { if (strcmp(s, G.eof_str) == 0) { while (getchar() != EOF) continue; p = s; goto ret; } } store_param(s); dbg_msg("args[]:'%s'", s); s = p; n_max_arg--; if (n_max_arg == 0) { goto ret; } state = NORM; } if (p == buf) { goto ret; } } ret: *p = '\0'; /* store_param(NULL) - caller will do it */ dbg_msg("return:'%s'", s); return s; } #else /* The variant does not support single quotes, double quotes or backslash */ static char* FAST_FUNC process_stdin(int n_max_chars, int n_max_arg, char *buf) { char *s = buf; /* start of the word */ char *p = s + strlen(buf); /* end of the word */ buf += n_max_chars; /* past buffer's end */ while (1) { int c = getchar(); if (c == EOF) { if (p == s) goto ret; } if (c == EOF || ISSPACE(c)) { if (p == s) continue; c = EOF; } *p++ = (c == EOF ? '\0' : c); if (c == EOF) { /* word's delimiter or EOF detected */ /* A full word is loaded */ if (G.eof_str) { if (strcmp(s, G.eof_str) == 0) { while (getchar() != EOF) continue; p = s; goto ret; } } store_param(s); dbg_msg("args[]:'%s'", s); s = p; n_max_arg--; if (n_max_arg == 0) { goto ret; } } if (p == buf) { goto ret; } } ret: *p = '\0'; /* store_param(NULL) - caller will do it */ dbg_msg("return:'%s'", s); return s; } #endif /* FEATURE_XARGS_SUPPORT_QUOTES */ #if ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM static char* FAST_FUNC process0_stdin(int n_max_chars, int n_max_arg, char *buf) { char *s = buf; /* start of the word */ char *p = s + strlen(buf); /* end of the word */ buf += n_max_chars; /* past buffer's end */ while (1) { int c = getchar(); if (c == EOF) { if (p == s) goto ret; c = '\0'; } *p++ = c; if (c == '\0') { /* word's delimiter or EOF detected */ /* A full word is loaded */ store_param(s); dbg_msg("args[]:'%s'", s); s = p; n_max_arg--; if (n_max_arg == 0) { goto ret; } } if (p == buf) { goto ret; } } ret: *p = '\0'; /* store_param(NULL) - caller will do it */ dbg_msg("return:'%s'", s); return s; } #endif /* FEATURE_XARGS_SUPPORT_ZERO_TERM */ #if ENABLE_FEATURE_XARGS_SUPPORT_CONFIRMATION /* Prompt the user for a response, and if the user responds affirmatively, return true; otherwise, return false. Uses "/dev/tty", not stdin. */ static int xargs_ask_confirmation(void) { FILE *tty_stream; int c, savec; tty_stream = xfopen_for_read(CURRENT_TTY); fputs(" ?...", stderr); fflush_all(); c = savec = getc(tty_stream); while (c != EOF && c != '\n') c = getc(tty_stream); fclose(tty_stream); return (savec == 'y' || savec == 'Y'); } #else # define xargs_ask_confirmation() 1 #endif //usage:#define xargs_trivial_usage //usage: "[OPTIONS] [PROG ARGS]" //usage:#define xargs_full_usage "\n\n" //usage: "Run PROG on every item given by stdin\n" //usage: "\nOptions:" //usage: IF_FEATURE_XARGS_SUPPORT_CONFIRMATION( //usage: "\n -p Ask user whether to run each command" //usage: ) //usage: "\n -r Don't run command if input is empty" //usage: IF_FEATURE_XARGS_SUPPORT_ZERO_TERM( //usage: "\n -0 Input is separated by NUL characters" //usage: ) //usage: "\n -t Print the command on stderr before execution" //usage: "\n -e[STR] STR stops input processing" //usage: "\n -n N Pass no more than N args to PROG" //usage: "\n -s N Pass command line of no more than N bytes" //usage: IF_FEATURE_XARGS_SUPPORT_TERMOPT( //usage: "\n -x Exit if size is exceeded" //usage: ) //usage:#define xargs_example_usage //usage: "$ ls | xargs gzip\n" //usage: "$ find . -name '*.c' -print | xargs rm\n" /* Correct regardless of combination of CONFIG_xxx */ enum { OPTBIT_VERBOSE = 0, OPTBIT_NO_EMPTY, OPTBIT_UPTO_NUMBER, OPTBIT_UPTO_SIZE, OPTBIT_EOF_STRING, OPTBIT_EOF_STRING1, IF_FEATURE_XARGS_SUPPORT_CONFIRMATION(OPTBIT_INTERACTIVE,) IF_FEATURE_XARGS_SUPPORT_TERMOPT( OPTBIT_TERMINATE ,) IF_FEATURE_XARGS_SUPPORT_ZERO_TERM( OPTBIT_ZEROTERM ,) OPT_VERBOSE = 1 << OPTBIT_VERBOSE , OPT_NO_EMPTY = 1 << OPTBIT_NO_EMPTY , OPT_UPTO_NUMBER = 1 << OPTBIT_UPTO_NUMBER, OPT_UPTO_SIZE = 1 << OPTBIT_UPTO_SIZE , OPT_EOF_STRING = 1 << OPTBIT_EOF_STRING , /* GNU: -e[<param>] */ OPT_EOF_STRING1 = 1 << OPTBIT_EOF_STRING1, /* SUS: -E<param> */ OPT_INTERACTIVE = IF_FEATURE_XARGS_SUPPORT_CONFIRMATION((1 << OPTBIT_INTERACTIVE)) + 0, OPT_TERMINATE = IF_FEATURE_XARGS_SUPPORT_TERMOPT( (1 << OPTBIT_TERMINATE )) + 0, OPT_ZEROTERM = IF_FEATURE_XARGS_SUPPORT_ZERO_TERM( (1 << OPTBIT_ZEROTERM )) + 0, }; #define OPTION_STR "+trn:s:e::E:" \ IF_FEATURE_XARGS_SUPPORT_CONFIRMATION("p") \ IF_FEATURE_XARGS_SUPPORT_TERMOPT( "x") \ IF_FEATURE_XARGS_SUPPORT_ZERO_TERM( "0") int xargs_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; int xargs_main(int argc, char **argv) { int i; int child_error = 0; char *max_args; char *max_chars; char *buf; unsigned opt; int n_max_chars; int n_max_arg; #if ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM char* FAST_FUNC (*read_args)(int, int, char*) = process_stdin; #else #define read_args process_stdin #endif INIT_G(); #if ENABLE_DESKTOP && ENABLE_LONG_OPTS /* For example, Fedora's build system uses --no-run-if-empty */ applet_long_options = "no-run-if-empty\0" No_argument "r" ; #endif opt = getopt32(argv, OPTION_STR, &max_args, &max_chars, &G.eof_str, &G.eof_str); /* -E ""? You may wonder why not just omit -E? * This is used for portability: * old xargs was using "_" as default for -E / -e */ if ((opt & OPT_EOF_STRING1) && G.eof_str[0] == '\0') G.eof_str = NULL; if (opt & OPT_ZEROTERM) IF_FEATURE_XARGS_SUPPORT_ZERO_TERM(read_args = process0_stdin); argv += optind; argc -= optind; if (!argv[0]) { /* default behavior is to echo all the filenames */ *--argv = (char*)"echo"; argc++; } /* -s NUM default. fileutils-4.4.2 uses 128k, but I heasitate * to use such a big value - first need to change code to use * growable buffer instead of fixed one. */ n_max_chars = 32 * 1024; /* Make smaller if system does not allow our default value. * The Open Group Base Specifications Issue 6: * "The xargs utility shall limit the command line length such that * when the command line is invoked, the combined argument * and environment lists (see the exec family of functions * in the System Interfaces volume of IEEE Std 1003.1-2001) * shall not exceed {ARG_MAX}-2048 bytes". */ { long arg_max = 0; #if defined _SC_ARG_MAX arg_max = sysconf(_SC_ARG_MAX) - 2048; #elif defined ARG_MAX arg_max = ARG_MAX - 2048; #endif if (arg_max > 0 && n_max_chars > arg_max) n_max_chars = arg_max; } if (opt & OPT_UPTO_SIZE) { n_max_chars = xatou_range(max_chars, 1, INT_MAX); } /* Account for prepended fixed arguments */ { size_t n_chars = 0; for (i = 0; argv[i]; i++) { n_chars += strlen(argv[i]) + 1; } n_max_chars -= n_chars; } /* Sanity check */ if (n_max_chars <= 0) { bb_error_msg_and_die("can't fit single argument within argument list size limit"); } buf = xzalloc(n_max_chars + 1); n_max_arg = n_max_chars; if (opt & OPT_UPTO_NUMBER) { n_max_arg = xatou_range(max_args, 1, INT_MAX); /* Not necessary, we use growable args[]: */ /* if (n_max_arg > n_max_chars) n_max_arg = n_max_chars */ } /* Allocate pointers for execvp */ /* We can statically allocate (argc + n_max_arg + 1) elements * and do not bother with resizing args[], but on 64-bit machines * this results in args[] vector which is ~8 times bigger * than n_max_chars! That is, with n_max_chars == 20k, * args[] will take 160k (!), which will most likely be * almost entirely unused. */ /* See store_param() for matching 256-step growth logic */ G.args = xmalloc(sizeof(G.args[0]) * ((argc + 0xff) & ~0xff)); /* Store the command to be executed, part 1 */ for (i = 0; argv[i]; i++) G.args[i] = argv[i]; while (1) { char *rem; G.idx = argc; rem = read_args(n_max_chars, n_max_arg, buf); store_param(NULL); if (!G.args[argc]) { if (*rem != '\0') bb_error_msg_and_die("argument line too long"); if (opt & OPT_NO_EMPTY) break; } opt |= OPT_NO_EMPTY; if (opt & (OPT_INTERACTIVE | OPT_VERBOSE)) { const char *fmt = " %s" + 1; char **args = G.args; for (i = 0; args[i]; i++) { fprintf(stderr, fmt, args[i]); fmt = " %s"; } if (!(opt & OPT_INTERACTIVE)) bb_putchar_stderr('\n'); } if (!(opt & OPT_INTERACTIVE) || xargs_ask_confirmation()) { child_error = xargs_exec(); } if (child_error > 0 && child_error != 123) { break; } overlapping_strcpy(buf, rem); } /* while */ if (ENABLE_FEATURE_CLEAN_UP) { free(G.args); free(buf); } return child_error; } #ifdef TEST const char *applet_name = "debug stuff usage"; void bb_show_usage(void) { fprintf(stderr, "Usage: %s [-p] [-r] [-t] -[x] [-n max_arg] [-s max_chars]\n", applet_name); exit(EXIT_FAILURE); } int main(int argc, char **argv) { return xargs_main(argc, argv); } #endif /* TEST */