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
18 //config: bool "xargs (7.2 kb)"
21 //config: xargs is used to execute a specified command for
22 //config: every item from standard input.
24 //config:config FEATURE_XARGS_SUPPORT_CONFIRMATION
25 //config: bool "Enable -p: prompt and confirmation"
27 //config: depends on XARGS
29 //config: Support -p: prompt the user whether to run each command
30 //config: line and read a line from the terminal.
32 //config:config FEATURE_XARGS_SUPPORT_QUOTES
33 //config: bool "Enable single and double quotes and backslash"
35 //config: depends on XARGS
37 //config: Support quoting in the input.
39 //config:config FEATURE_XARGS_SUPPORT_TERMOPT
40 //config: bool "Enable -x: exit if -s or -n is exceeded"
42 //config: depends on XARGS
44 //config: Support -x: exit if the command size (see the -s or -n option)
45 //config: is exceeded.
47 //config:config FEATURE_XARGS_SUPPORT_ZERO_TERM
48 //config: bool "Enable -0: NUL-terminated input"
50 //config: depends on XARGS
52 //config: Support -0: input items are terminated by a NUL character
53 //config: instead of whitespace, and the quotes and backslash
54 //config: are not special.
56 //config:config FEATURE_XARGS_SUPPORT_REPL_STR
57 //config: bool "Enable -I STR: string to replace"
59 //config: depends on XARGS
61 //config: Support -I STR and -i[STR] options.
63 //config:config FEATURE_XARGS_SUPPORT_PARALLEL
64 //config: bool "Enable -P N: processes to run in parallel"
66 //config: depends on XARGS
68 //config:config FEATURE_XARGS_SUPPORT_ARGS_FILE
69 //config: bool "Enable -a FILE: use FILE instead of stdin"
71 //config: depends on XARGS
73 //applet:IF_XARGS(APPLET_NOEXEC(xargs, xargs, BB_DIR_USR_BIN, BB_SUID_DROP, xargs))
75 //kbuild:lib-$(CONFIG_XARGS) += xargs.o
78 #include "common_bufsiz.h"
80 /* This is a NOEXEC applet. Be very careful! */
83 //#define dbg_msg(...) bb_error_msg(__VA_ARGS__)
84 #define dbg_msg(...) ((void)0)
88 # ifndef ENABLE_FEATURE_XARGS_SUPPORT_CONFIRMATION
89 # define ENABLE_FEATURE_XARGS_SUPPORT_CONFIRMATION 1
91 # ifndef ENABLE_FEATURE_XARGS_SUPPORT_QUOTES
92 # define ENABLE_FEATURE_XARGS_SUPPORT_QUOTES 1
94 # ifndef ENABLE_FEATURE_XARGS_SUPPORT_TERMOPT
95 # define ENABLE_FEATURE_XARGS_SUPPORT_TERMOPT 1
97 # ifndef ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM
98 # define ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM 1
105 #if ENABLE_FEATURE_XARGS_SUPPORT_REPL_STR
107 const char *repl_str;
112 #if ENABLE_FEATURE_XARGS_SUPPORT_PARALLEL
116 smalluint xargs_exitcode;
118 #define G (*(struct globals*)bb_common_bufsiz1)
119 #define INIT_G() do { \
120 setup_common_bufsiz(); \
121 G.eof_str = NULL; /* need to clear by hand because we are NOEXEC applet */ \
123 IF_FEATURE_XARGS_SUPPORT_PARALLEL(G.running_procs = 0;) \
124 IF_FEATURE_XARGS_SUPPORT_PARALLEL(G.max_procs = 1;) \
125 G.xargs_exitcode = 0; \
126 IF_FEATURE_XARGS_SUPPORT_REPL_STR(G.repl_str = "{}";) \
127 IF_FEATURE_XARGS_SUPPORT_REPL_STR(G.eol_ch = '\n';) \
132 * Returns 0 if xargs should continue (but may set G.xargs_exitcode to 123).
133 * Else sets G.xargs_exitcode to error code and returns nonzero.
135 * If G.max_procs == 0, performs final waitpid() loop for all children.
137 static int xargs_exec(void)
141 #if !ENABLE_FEATURE_XARGS_SUPPORT_PARALLEL
142 status = spawn_and_wait(G.args);
144 if (G.max_procs == 1) {
145 status = spawn_and_wait(G.args);
150 if (G.running_procs >= G.max_procs)
151 pid = safe_waitpid(-1, &wstat, 0);
153 pid = wait_any_nohang(&wstat);
155 /* We may have children we don't know about:
156 * sh -c 'sleep 1 & exec xargs ...'
157 * Do not make G.running_procs go negative.
159 if (G.running_procs != 0)
161 status = WIFSIGNALED(wstat)
162 ? 0x180 + WTERMSIG(wstat)
163 : WEXITSTATUS(wstat);
164 if (status > 0 && status < 255) {
165 /* See below why 123 does not abort */
166 G.xargs_exitcode = 123;
170 goto again; /* maybe we have more children? */
171 /* else: "bad" status, will bail out */
172 } else if (G.max_procs != 0) {
173 /* Not in final waitpid() loop,
174 * and G.running_procs < G.max_procs: start more procs
176 status = spawn(G.args);
177 /* here "status" actually holds pid, or -1 */
182 /* else: status == -1 (failed to fork or exec) */
184 /* final waitpid() loop: must be ECHILD "no more children" */
190 * """xargs exits with the following status:
192 * 123 if any invocation of the command exited with status 1-125
193 * 124 if the command exited with status 255
194 * ("""If any invocation of the command exits with a status of 255,
195 * xargs will stop immediately without reading any further input.
196 * An error message is issued on stderr when this happens.""")
197 * 125 if the command is killed by a signal
198 * 126 if the command cannot be run
199 * 127 if the command is not found
200 * 1 if some other error occurred."""
203 bb_simple_perror_msg(G.args[0]);
204 status = (errno == ENOENT) ? 127 : 126;
206 else if (status >= 0x180) {
207 bb_error_msg("'%s' terminated by signal %u",
208 G.args[0], status - 0x180);
211 else if (status != 0) {
213 bb_error_msg("%s: exited with status 255; aborting", G.args[0]);
217 /* "123 if any invocation of the command exited with status 1-125"
218 * This implies that nonzero exit code is remembered,
219 * but does not cause xargs to stop: we return 0.
221 G.xargs_exitcode = 123;
226 G.xargs_exitcode = status;
230 /* In POSIX/C locale isspace is only these chars: "\t\n\v\f\r" and space.
231 * "\t\n\v\f\r" happen to have ASCII codes 9,10,11,12,13.
233 #define ISSPACE(a) ({ unsigned char xargs__isspace = (a) - 9; xargs__isspace == (' ' - 9) || xargs__isspace <= (13 - 9); })
235 static void store_param(char *s)
237 /* Grow by 256 elements at once */
238 if (!(G.idx & 0xff)) { /* G.idx == N*256? */
239 /* Enlarge, make G.args[(N+1)*256 - 1] last valid idx */
240 G.args = xrealloc(G.args, sizeof(G.args[0]) * (G.idx + 0x100));
246 * Read characters into buf[n_max_chars+1], and when parameter delimiter
247 * is seen, store the address of a new parameter to args[].
248 * If reading discovers that last chars do not form the complete
249 * parameter, the pointer to the first such "tail character" is returned.
250 * (buf has extra byte at the end to accommodate terminating NUL
251 * of "tail characters" string).
252 * Otherwise, the returned pointer points to NUL byte.
253 * On entry, buf[] may contain some "seed chars" which are to become
254 * the beginning of the first parameter.
257 #if ENABLE_FEATURE_XARGS_SUPPORT_QUOTES
258 static char* FAST_FUNC process_stdin(int n_max_chars, int n_max_arg, char *buf)
264 char q = '\0'; /* quote char */
266 char *s = buf; /* start of the word */
267 char *p = s + strlen(buf); /* end of the word */
269 buf += n_max_chars; /* past buffer's end */
271 /* "goto ret" is used instead of "break" to make control flow
281 if (state == BACKSLASH) {
285 if (state == QUOTE) {
290 } else { /* if (state == NORM) */
301 } else if (c == '\'' || c == '"') {
310 if (state == SPACE) { /* word's delimiter or EOF detected */
312 bb_error_msg_and_die("unmatched %s quote",
313 q == '\'' ? "single" : "double");
315 /* A full word is loaded */
317 if (strcmp(s, G.eof_str) == 0) {
318 while (getchar() != EOF)
325 dbg_msg("args[]:'%s'", s);
328 if (n_max_arg == 0) {
339 /* store_param(NULL) - caller will do it */
340 dbg_msg("return:'%s'", s);
344 /* The variant does not support single quotes, double quotes or backslash */
345 static char* FAST_FUNC process_stdin(int n_max_chars, int n_max_arg, char *buf)
347 char *s = buf; /* start of the word */
348 char *p = s + strlen(buf); /* end of the word */
350 buf += n_max_chars; /* past buffer's end */
358 if (c == EOF || ISSPACE(c)) {
363 *p++ = (c == EOF ? '\0' : c);
364 if (c == EOF) { /* word's delimiter or EOF detected */
365 /* A full word is loaded */
367 if (strcmp(s, G.eof_str) == 0) {
368 while (getchar() != EOF)
375 dbg_msg("args[]:'%s'", s);
378 if (n_max_arg == 0) {
388 /* store_param(NULL) - caller will do it */
389 dbg_msg("return:'%s'", s);
392 #endif /* FEATURE_XARGS_SUPPORT_QUOTES */
394 #if ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM
395 static char* FAST_FUNC process0_stdin(int n_max_chars, int n_max_arg, char *buf)
397 char *s = buf; /* start of the word */
398 char *p = s + strlen(buf); /* end of the word */
400 buf += n_max_chars; /* past buffer's end */
410 if (c == '\0') { /* NUL or EOF detected */
411 /* A full word is loaded */
413 dbg_msg("args[]:'%s'", s);
416 if (n_max_arg == 0) {
426 /* store_param(NULL) - caller will do it */
427 dbg_msg("return:'%s'", s);
430 #endif /* FEATURE_XARGS_SUPPORT_ZERO_TERM */
432 #if ENABLE_FEATURE_XARGS_SUPPORT_REPL_STR
434 * Used if -I<repl> was specified.
435 * In this mode, words aren't appended to PROG ARGS.
436 * Instead, entire input line is read, then <repl> string
437 * in every PROG and ARG is replaced with the line:
438 * echo -e "ho ho\nhi" | xargs -I_ cmd __ _
439 * results in "cmd 'ho hoho ho' 'ho ho'"; "cmd 'hihi' 'hi'".
440 * -n MAX_ARGS seems to be ignored.
441 * Tested with GNU findutils 4.5.10.
443 //FIXME: n_max_chars is not handled the same way as in GNU findutils.
444 //FIXME: quoting is not implemented.
445 static char* FAST_FUNC process_stdin_with_replace(int n_max_chars, int n_max_arg UNUSED_PARAM, char *buf)
450 /* Free strings from last invocation, if any */
451 for (i = 0; G.args && G.args[i]; i++)
452 if (G.args[i] != G.argv[i])
455 end = buf + n_max_chars;
460 if (c == EOF || c == G.eol_ch) {
462 goto ret; /* empty line */
466 if (c == '\0') { /* EOL or EOF detected */
469 char *arg = G.argv[i];
470 int count = count_strstr(arg, G.repl_str);
472 arg = xmalloc_substitute_string(arg, count, G.repl_str, buf);
474 dbg_msg("args[]:'%s'", arg);
486 /* store_param(NULL) - caller will do it */
487 dbg_msg("return:'%s'", buf);
492 #if ENABLE_FEATURE_XARGS_SUPPORT_CONFIRMATION
493 /* Prompt the user for a response, and
494 * if user responds affirmatively, return true;
495 * otherwise, return false. Uses "/dev/tty", not stdin.
497 static int xargs_ask_confirmation(void)
502 tty_stream = xfopen_for_read(CURRENT_TTY);
504 fputs(" ?...", stderr);
505 r = bb_ask_y_confirmation_FILE(tty_stream);
512 # define xargs_ask_confirmation() 1
515 //usage:#define xargs_trivial_usage
516 //usage: "[OPTIONS] [PROG ARGS]"
517 //usage:#define xargs_full_usage "\n\n"
518 //usage: "Run PROG on every item given by stdin\n"
519 //usage: IF_FEATURE_XARGS_SUPPORT_ZERO_TERM(
520 //usage: "\n -0 Input is separated by NULs"
522 //usage: IF_FEATURE_XARGS_SUPPORT_ARGS_FILE(
523 //usage: "\n -a FILE Read from FILE instead of stdin"
525 //usage: "\n -r Don't run command if input is empty"
526 //usage: "\n -t Print the command on stderr before execution"
527 //usage: IF_FEATURE_XARGS_SUPPORT_CONFIRMATION(
528 //usage: "\n -p Ask user whether to run each command"
530 //usage: "\n -E STR,-e[STR] STR stops input processing"
531 //usage: IF_FEATURE_XARGS_SUPPORT_REPL_STR(
532 //usage: "\n -I STR Replace STR within PROG ARGS with input line"
534 //usage: "\n -n N Pass no more than N args to PROG"
535 //usage: "\n -s N Pass command line of no more than N bytes"
536 //usage: IF_FEATURE_XARGS_SUPPORT_PARALLEL(
537 //usage: "\n -P N Run up to N PROGs in parallel"
539 //usage: IF_FEATURE_XARGS_SUPPORT_TERMOPT(
540 //usage: "\n -x Exit if size is exceeded"
542 //usage:#define xargs_example_usage
543 //usage: "$ ls | xargs gzip\n"
544 //usage: "$ find . -name '*.c' -print | xargs rm\n"
546 /* Correct regardless of combination of CONFIG_xxx */
554 IF_FEATURE_XARGS_SUPPORT_CONFIRMATION(OPTBIT_INTERACTIVE,)
555 IF_FEATURE_XARGS_SUPPORT_TERMOPT( OPTBIT_TERMINATE ,)
556 IF_FEATURE_XARGS_SUPPORT_ZERO_TERM( OPTBIT_ZEROTERM ,)
557 IF_FEATURE_XARGS_SUPPORT_REPL_STR( OPTBIT_REPLSTR ,)
558 IF_FEATURE_XARGS_SUPPORT_REPL_STR( OPTBIT_REPLSTR1 ,)
560 OPT_VERBOSE = 1 << OPTBIT_VERBOSE ,
561 OPT_NO_EMPTY = 1 << OPTBIT_NO_EMPTY ,
562 OPT_UPTO_NUMBER = 1 << OPTBIT_UPTO_NUMBER,
563 OPT_UPTO_SIZE = 1 << OPTBIT_UPTO_SIZE ,
564 OPT_EOF_STRING = 1 << OPTBIT_EOF_STRING , /* GNU: -e[<param>] */
565 OPT_EOF_STRING1 = 1 << OPTBIT_EOF_STRING1, /* SUS: -E<param> */
566 OPT_INTERACTIVE = IF_FEATURE_XARGS_SUPPORT_CONFIRMATION((1 << OPTBIT_INTERACTIVE)) + 0,
567 OPT_TERMINATE = IF_FEATURE_XARGS_SUPPORT_TERMOPT( (1 << OPTBIT_TERMINATE )) + 0,
568 OPT_ZEROTERM = IF_FEATURE_XARGS_SUPPORT_ZERO_TERM( (1 << OPTBIT_ZEROTERM )) + 0,
569 OPT_REPLSTR = IF_FEATURE_XARGS_SUPPORT_REPL_STR( (1 << OPTBIT_REPLSTR )) + 0,
570 OPT_REPLSTR1 = IF_FEATURE_XARGS_SUPPORT_REPL_STR( (1 << OPTBIT_REPLSTR1 )) + 0,
572 #define OPTION_STR "+trn:s:e::E:" \
573 IF_FEATURE_XARGS_SUPPORT_CONFIRMATION("p") \
574 IF_FEATURE_XARGS_SUPPORT_TERMOPT( "x") \
575 IF_FEATURE_XARGS_SUPPORT_ZERO_TERM( "0") \
576 IF_FEATURE_XARGS_SUPPORT_REPL_STR( "I:i::") \
577 IF_FEATURE_XARGS_SUPPORT_PARALLEL( "P:+") \
578 IF_FEATURE_XARGS_SUPPORT_ARGS_FILE( "a:")
580 int xargs_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
581 int xargs_main(int argc UNUSED_PARAM, char **argv)
591 #if ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM \
592 || ENABLE_FEATURE_XARGS_SUPPORT_REPL_STR
593 char* FAST_FUNC (*read_args)(int, int, char*) = process_stdin;
595 #define read_args process_stdin
597 IF_FEATURE_XARGS_SUPPORT_ARGS_FILE(char *opt_a = NULL;)
601 opt = getopt32long(argv, OPTION_STR,
602 "no-run-if-empty\0" No_argument "r",
603 &max_args, &max_chars, &G.eof_str, &G.eof_str
604 IF_FEATURE_XARGS_SUPPORT_REPL_STR(, &G.repl_str, &G.repl_str)
605 IF_FEATURE_XARGS_SUPPORT_PARALLEL(, &G.max_procs)
606 IF_FEATURE_XARGS_SUPPORT_ARGS_FILE(, &opt_a)
609 #if ENABLE_FEATURE_XARGS_SUPPORT_PARALLEL
610 if (G.max_procs <= 0) /* -P0 means "run lots of them" */
611 G.max_procs = 100; /* let's not go crazy high */
614 #if ENABLE_FEATURE_XARGS_SUPPORT_ARGS_FILE
616 xmove_fd(xopen(opt_a, O_RDONLY), 0);
619 /* -E ""? You may wonder why not just omit -E?
620 * This is used for portability:
621 * old xargs was using "_" as default for -E / -e */
622 if ((opt & OPT_EOF_STRING1) && G.eof_str[0] == '\0')
625 if (opt & OPT_ZEROTERM) {
626 IF_FEATURE_XARGS_SUPPORT_ZERO_TERM(read_args = process0_stdin;)
627 IF_FEATURE_XARGS_SUPPORT_REPL_STR(G.eol_ch = '\0';)
633 /* default behavior is to echo all the filenames */
634 *--argv = (char*)"echo";
639 * The Open Group Base Specifications Issue 6:
640 * "The xargs utility shall limit the command line length such that
641 * when the command line is invoked, the combined argument
642 * and environment lists (see the exec family of functions
643 * in the System Interfaces volume of IEEE Std 1003.1-2001)
644 * shall not exceed {ARG_MAX}-2048 bytes".
646 n_max_chars = bb_arg_max();
647 if (n_max_chars > 32 * 1024)
648 n_max_chars = 32 * 1024;
650 * POSIX suggests substracting 2048 bytes from sysconf(_SC_ARG_MAX)
651 * so that the process may safely modify its environment.
655 if (opt & OPT_UPTO_SIZE) {
656 n_max_chars = xatou_range(max_chars, 1, INT_MAX);
658 /* Account for prepended fixed arguments */
661 for (i = 0; argv[i]; i++) {
662 n_chars += strlen(argv[i]) + 1;
664 n_max_chars -= n_chars;
667 if (n_max_chars <= 0) {
668 bb_simple_error_msg_and_die("can't fit single argument within argument list size limit");
671 buf = xzalloc(n_max_chars + 1);
673 n_max_arg = n_max_chars;
674 if (opt & OPT_UPTO_NUMBER) {
675 n_max_arg = xatou_range(max_args, 1, INT_MAX);
676 /* Not necessary, we use growable args[]: */
677 /* if (n_max_arg > n_max_chars) n_max_arg = n_max_chars */
680 #if ENABLE_FEATURE_XARGS_SUPPORT_REPL_STR
681 if (opt & (OPT_REPLSTR | OPT_REPLSTR1)) {
684 * Unmodified args are kept in G.argv[i],
685 * G.args[i] receives malloced G.argv[i] with <str> replaced
686 * with input line. Setting this up:
690 read_args = process_stdin_with_replace;
691 /* Make -I imply -r. GNU findutils seems to do the same: */
692 /* (otherwise "echo -n | xargs -I% echo %" would SEGV) */
697 /* Store the command to be executed, part 1.
698 * We can statically allocate (argc + n_max_arg + 1) elements
699 * and do not bother with resizing args[], but on 64-bit machines
700 * this results in args[] vector which is ~8 times bigger
701 * than n_max_chars! That is, with n_max_chars == 20k,
702 * args[] will take 160k (!), which will most likely be
703 * almost entirely unused.
705 for (i = 0; argv[i]; i++)
706 store_param(argv[i]);
714 rem = read_args(n_max_chars, n_max_arg, buf);
717 if (!G.args[initial_idx]) { /* not even one ARG was added? */
719 bb_simple_error_msg_and_die("argument line too long");
720 if (opt & OPT_NO_EMPTY)
725 if (opt & (OPT_INTERACTIVE | OPT_VERBOSE)) {
726 const char *fmt = " %s" + 1;
727 char **args = G.args;
728 for (i = 0; args[i]; i++) {
729 fprintf(stderr, fmt, args[i]);
732 if (!(opt & OPT_INTERACTIVE))
733 bb_putchar_stderr('\n');
736 if (!(opt & OPT_INTERACTIVE) || xargs_ask_confirmation()) {
737 if (xargs_exec() != 0)
738 break; /* G.xargs_exitcode is set by xargs_exec() */
741 overlapping_strcpy(buf, rem);
744 if (ENABLE_FEATURE_CLEAN_UP) {
749 #if ENABLE_FEATURE_XARGS_SUPPORT_PARALLEL
751 xargs_exec(); /* final waitpid() loop */
754 return G.xargs_exitcode;
760 const char *applet_name = "debug stuff usage";
762 void bb_show_usage(void)
764 fprintf(stderr, "Usage: %s [-p] [-r] [-t] -[x] [-n max_arg] [-s max_chars]\n",
769 int main(int argc, char **argv)
771 return xargs_main(argc, argv);