1 /* vi: set sw=4 ts=4: */
3 * Mini xargs implementation for busybox
5 * (C) 2002,2003 by Vladimir Oleynik <dzo@simtreas.ru>
8 * - Mark Whitley and Glenn McGrath for stimulus to rewrite :)
9 * - Mike Rendell <michael@cs.mun.ca>
10 * and David MacKenzie <djm@gnu.ai.mit.edu>.
12 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
14 * xargs is described in the Single Unix Specification v3 at
15 * http://www.opengroup.org/onlinepubs/007904975/utilities/xargs.html
19 //config: bool "xargs"
22 //config: xargs is used to execute a specified command for
23 //config: every item from standard input.
25 //config:config FEATURE_XARGS_SUPPORT_CONFIRMATION
26 //config: bool "Enable -p: prompt and confirmation"
28 //config: depends on XARGS
30 //config: Support -p: prompt the user whether to run each command
31 //config: line and read a line from the terminal.
33 //config:config FEATURE_XARGS_SUPPORT_QUOTES
34 //config: bool "Enable single and double quotes and backslash"
36 //config: depends on XARGS
38 //config: Support quoting in the input.
40 //config:config FEATURE_XARGS_SUPPORT_TERMOPT
41 //config: bool "Enable -x: exit if -s or -n is exceeded"
43 //config: depends on XARGS
45 //config: Support -x: exit if the command size (see the -s or -n option)
46 //config: is exceeded.
48 //config:config FEATURE_XARGS_SUPPORT_ZERO_TERM
49 //config: bool "Enable -0: NUL-terminated input"
51 //config: depends on XARGS
53 //config: Support -0: input items are terminated by a NUL character
54 //config: instead of whitespace, and the quotes and backslash
55 //config: are not special.
57 //applet:IF_XARGS(APPLET_NOEXEC(xargs, xargs, BB_DIR_USR_BIN, BB_SUID_DROP, xargs))
59 //kbuild:lib-$(CONFIG_XARGS) += xargs.o
63 /* This is a NOEXEC applet. Be very careful! */
66 //#define dbg_msg(...) bb_error_msg(__VA_ARGS__)
67 #define dbg_msg(...) ((void)0)
71 # ifndef ENABLE_FEATURE_XARGS_SUPPORT_CONFIRMATION
72 # define ENABLE_FEATURE_XARGS_SUPPORT_CONFIRMATION 1
74 # ifndef ENABLE_FEATURE_XARGS_SUPPORT_QUOTES
75 # define ENABLE_FEATURE_XARGS_SUPPORT_QUOTES 1
77 # ifndef ENABLE_FEATURE_XARGS_SUPPORT_TERMOPT
78 # define ENABLE_FEATURE_XARGS_SUPPORT_TERMOPT 1
80 # ifndef ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM
81 # define ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM 1
91 #define G (*(struct globals*)&bb_common_bufsiz1)
92 #define INIT_G() do { \
93 G.eof_str = NULL; /* need to clear by hand because we are NOEXEC applet */ \
98 * This function has special algorithm.
99 * Don't use fork and include to main!
101 static int xargs_exec(void)
105 status = spawn_and_wait(G.args);
107 bb_simple_perror_msg(G.args[0]);
108 return errno == ENOENT ? 127 : 126;
111 bb_error_msg("%s: exited with status 255; aborting", G.args[0]);
114 if (status >= 0x180) {
115 bb_error_msg("%s: terminated by signal %d",
116 G.args[0], status - 0x180);
124 /* In POSIX/C locale isspace is only these chars: "\t\n\v\f\r" and space.
125 * "\t\n\v\f\r" happen to have ASCII codes 9,10,11,12,13.
127 #define ISSPACE(a) ({ unsigned char xargs__isspace = (a) - 9; xargs__isspace == (' ' - 9) || xargs__isspace <= (13 - 9); })
129 static void store_param(char *s)
131 /* Grow by 256 elements at once */
132 if (!(G.idx & 0xff)) { /* G.idx == N*256 */
133 /* Enlarge, make G.args[(N+1)*256 - 1] last valid idx */
134 G.args = xrealloc(G.args, sizeof(G.args[0]) * (G.idx + 0x100));
140 * Read characters into buf[n_max_chars+1], and when parameter delimiter
141 * is seen, store the address of a new parameter to args[].
142 * If reading discovers that last chars do not form the complete
143 * parameter, the pointer to the first such "tail character" is returned.
144 * (buf has extra byte at the end to accomodate terminating NUL
145 * of "tail characters" string).
146 * Otherwise, the returned pointer points to NUL byte.
147 * On entry, buf[] may contain some "seed chars" which are to become
148 * the beginning of the first parameter.
151 #if ENABLE_FEATURE_XARGS_SUPPORT_QUOTES
152 static char* FAST_FUNC process_stdin(int n_max_chars, int n_max_arg, char *buf)
158 char q = '\0'; /* quote char */
160 char *s = buf; /* start of the word */
161 char *p = s + strlen(buf); /* end of the word */
163 buf += n_max_chars; /* past buffer's end */
165 /* "goto ret" is used instead of "break" to make control flow
175 if (state == BACKSLASH) {
179 if (state == QUOTE) {
184 } else { /* if (state == NORM) */
195 } else if (c == '\'' || c == '"') {
204 if (state == SPACE) { /* word's delimiter or EOF detected */
206 bb_error_msg_and_die("unmatched %s quote",
207 q == '\'' ? "single" : "double");
209 /* A full word is loaded */
211 if (strcmp(s, G.eof_str) == 0) {
212 while (getchar() != EOF)
219 dbg_msg("args[]:'%s'", s);
222 if (n_max_arg == 0) {
233 /* store_param(NULL) - caller will do it */
234 dbg_msg("return:'%s'", s);
238 /* The variant does not support single quotes, double quotes or backslash */
239 static char* FAST_FUNC process_stdin(int n_max_chars, int n_max_arg, char *buf)
241 char *s = buf; /* start of the word */
242 char *p = s + strlen(buf); /* end of the word */
244 buf += n_max_chars; /* past buffer's end */
252 if (c == EOF || ISSPACE(c)) {
257 *p++ = (c == EOF ? '\0' : c);
258 if (c == EOF) { /* word's delimiter or EOF detected */
259 /* A full word is loaded */
261 if (strcmp(s, G.eof_str) == 0) {
262 while (getchar() != EOF)
269 dbg_msg("args[]:'%s'", s);
272 if (n_max_arg == 0) {
282 /* store_param(NULL) - caller will do it */
283 dbg_msg("return:'%s'", s);
286 #endif /* FEATURE_XARGS_SUPPORT_QUOTES */
288 #if ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM
289 static char* FAST_FUNC process0_stdin(int n_max_chars, int n_max_arg, char *buf)
291 char *s = buf; /* start of the word */
292 char *p = s + strlen(buf); /* end of the word */
294 buf += n_max_chars; /* past buffer's end */
304 if (c == '\0') { /* word's delimiter or EOF detected */
305 /* A full word is loaded */
307 dbg_msg("args[]:'%s'", s);
310 if (n_max_arg == 0) {
320 /* store_param(NULL) - caller will do it */
321 dbg_msg("return:'%s'", s);
324 #endif /* FEATURE_XARGS_SUPPORT_ZERO_TERM */
326 #if ENABLE_FEATURE_XARGS_SUPPORT_CONFIRMATION
327 /* Prompt the user for a response, and
328 if the user responds affirmatively, return true;
329 otherwise, return false. Uses "/dev/tty", not stdin. */
330 static int xargs_ask_confirmation(void)
335 tty_stream = xfopen_for_read(CURRENT_TTY);
336 fputs(" ?...", stderr);
338 c = savec = getc(tty_stream);
339 while (c != EOF && c != '\n')
340 c = getc(tty_stream);
342 return (savec == 'y' || savec == 'Y');
345 # define xargs_ask_confirmation() 1
348 //usage:#define xargs_trivial_usage
349 //usage: "[OPTIONS] [PROG ARGS]"
350 //usage:#define xargs_full_usage "\n\n"
351 //usage: "Run PROG on every item given by stdin\n"
352 //usage: IF_FEATURE_XARGS_SUPPORT_CONFIRMATION(
353 //usage: "\n -p Ask user whether to run each command"
355 //usage: "\n -r Don't run command if input is empty"
356 //usage: IF_FEATURE_XARGS_SUPPORT_ZERO_TERM(
357 //usage: "\n -0 Input is separated by NUL characters"
359 //usage: "\n -t Print the command on stderr before execution"
360 //usage: "\n -e[STR] STR stops input processing"
361 //usage: "\n -n N Pass no more than N args to PROG"
362 //usage: "\n -s N Pass command line of no more than N bytes"
363 //usage: IF_FEATURE_XARGS_SUPPORT_TERMOPT(
364 //usage: "\n -x Exit if size is exceeded"
366 //usage:#define xargs_example_usage
367 //usage: "$ ls | xargs gzip\n"
368 //usage: "$ find . -name '*.c' -print | xargs rm\n"
370 /* Correct regardless of combination of CONFIG_xxx */
378 IF_FEATURE_XARGS_SUPPORT_CONFIRMATION(OPTBIT_INTERACTIVE,)
379 IF_FEATURE_XARGS_SUPPORT_TERMOPT( OPTBIT_TERMINATE ,)
380 IF_FEATURE_XARGS_SUPPORT_ZERO_TERM( OPTBIT_ZEROTERM ,)
382 OPT_VERBOSE = 1 << OPTBIT_VERBOSE ,
383 OPT_NO_EMPTY = 1 << OPTBIT_NO_EMPTY ,
384 OPT_UPTO_NUMBER = 1 << OPTBIT_UPTO_NUMBER,
385 OPT_UPTO_SIZE = 1 << OPTBIT_UPTO_SIZE ,
386 OPT_EOF_STRING = 1 << OPTBIT_EOF_STRING , /* GNU: -e[<param>] */
387 OPT_EOF_STRING1 = 1 << OPTBIT_EOF_STRING1, /* SUS: -E<param> */
388 OPT_INTERACTIVE = IF_FEATURE_XARGS_SUPPORT_CONFIRMATION((1 << OPTBIT_INTERACTIVE)) + 0,
389 OPT_TERMINATE = IF_FEATURE_XARGS_SUPPORT_TERMOPT( (1 << OPTBIT_TERMINATE )) + 0,
390 OPT_ZEROTERM = IF_FEATURE_XARGS_SUPPORT_ZERO_TERM( (1 << OPTBIT_ZEROTERM )) + 0,
392 #define OPTION_STR "+trn:s:e::E:" \
393 IF_FEATURE_XARGS_SUPPORT_CONFIRMATION("p") \
394 IF_FEATURE_XARGS_SUPPORT_TERMOPT( "x") \
395 IF_FEATURE_XARGS_SUPPORT_ZERO_TERM( "0")
397 int xargs_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
398 int xargs_main(int argc, char **argv)
408 #if ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM
409 char* FAST_FUNC (*read_args)(int, int, char*) = process_stdin;
411 #define read_args process_stdin
416 #if ENABLE_DESKTOP && ENABLE_LONG_OPTS
417 /* For example, Fedora's build system uses --no-run-if-empty */
418 applet_long_options =
419 "no-run-if-empty\0" No_argument "r"
422 opt = getopt32(argv, OPTION_STR, &max_args, &max_chars, &G.eof_str, &G.eof_str);
424 /* -E ""? You may wonder why not just omit -E?
425 * This is used for portability:
426 * old xargs was using "_" as default for -E / -e */
427 if ((opt & OPT_EOF_STRING1) && G.eof_str[0] == '\0')
430 if (opt & OPT_ZEROTERM)
431 IF_FEATURE_XARGS_SUPPORT_ZERO_TERM(read_args = process0_stdin);
436 /* default behavior is to echo all the filenames */
437 *--argv = (char*)"echo";
441 /* -s NUM default. fileutils-4.4.2 uses 128k, but I heasitate
442 * to use such a big value - first need to change code to use
443 * growable buffer instead of fixed one.
445 n_max_chars = 32 * 1024;
446 /* Make smaller if system does not allow our default value.
447 * The Open Group Base Specifications Issue 6:
448 * "The xargs utility shall limit the command line length such that
449 * when the command line is invoked, the combined argument
450 * and environment lists (see the exec family of functions
451 * in the System Interfaces volume of IEEE Std 1003.1-2001)
452 * shall not exceed {ARG_MAX}-2048 bytes".
456 #if defined _SC_ARG_MAX
457 arg_max = sysconf(_SC_ARG_MAX) - 2048;
458 #elif defined ARG_MAX
459 arg_max = ARG_MAX - 2048;
461 if (arg_max > 0 && n_max_chars > arg_max)
462 n_max_chars = arg_max;
464 if (opt & OPT_UPTO_SIZE) {
465 n_max_chars = xatou_range(max_chars, 1, INT_MAX);
467 /* Account for prepended fixed arguments */
470 for (i = 0; argv[i]; i++) {
471 n_chars += strlen(argv[i]) + 1;
473 n_max_chars -= n_chars;
476 if (n_max_chars <= 0) {
477 bb_error_msg_and_die("can't fit single argument within argument list size limit");
480 buf = xzalloc(n_max_chars + 1);
482 n_max_arg = n_max_chars;
483 if (opt & OPT_UPTO_NUMBER) {
484 n_max_arg = xatou_range(max_args, 1, INT_MAX);
485 /* Not necessary, we use growable args[]: */
486 /* if (n_max_arg > n_max_chars) n_max_arg = n_max_chars */
489 /* Allocate pointers for execvp */
490 /* We can statically allocate (argc + n_max_arg + 1) elements
491 * and do not bother with resizing args[], but on 64-bit machines
492 * this results in args[] vector which is ~8 times bigger
493 * than n_max_chars! That is, with n_max_chars == 20k,
494 * args[] will take 160k (!), which will most likely be
495 * almost entirely unused.
497 /* See store_param() for matching 256-step growth logic */
498 G.args = xmalloc(sizeof(G.args[0]) * ((argc + 0xff) & ~0xff));
500 /* Store the command to be executed, part 1 */
501 for (i = 0; argv[i]; i++)
508 rem = read_args(n_max_chars, n_max_arg, buf);
513 bb_error_msg_and_die("argument line too long");
514 if (opt & OPT_NO_EMPTY)
519 if (opt & (OPT_INTERACTIVE | OPT_VERBOSE)) {
520 const char *fmt = " %s" + 1;
521 char **args = G.args;
522 for (i = 0; args[i]; i++) {
523 fprintf(stderr, fmt, args[i]);
526 if (!(opt & OPT_INTERACTIVE))
527 bb_putchar_stderr('\n');
530 if (!(opt & OPT_INTERACTIVE) || xargs_ask_confirmation()) {
531 child_error = xargs_exec();
534 if (child_error > 0 && child_error != 123) {
538 overlapping_strcpy(buf, rem);
541 if (ENABLE_FEATURE_CLEAN_UP) {
552 const char *applet_name = "debug stuff usage";
554 void bb_show_usage(void)
556 fprintf(stderr, "Usage: %s [-p] [-r] [-t] -[x] [-n max_arg] [-s max_chars]\n",
561 int main(int argc, char **argv)
563 return xargs_main(argc, argv);