2 * SPDX-License-Identifier: BSD-3-Clause
4 * Copyright (c) 1990, 1993
5 * The Regents of the University of California. All rights reserved.
7 * This code is derived from software contributed to Berkeley by
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * $xMach: xargs.c,v 1.6 2002/02/23 05:27:47 tim Exp $
39 static const char copyright[] =
40 "@(#) Copyright (c) 1990, 1993\n\
41 The Regents of the University of California. All rights reserved.\n";
45 static char sccsid[] = "@(#)xargs.c 8.1 (Berkeley) 6/6/93";
48 #include <sys/cdefs.h>
49 __FBSDID("$FreeBSD$");
51 #include <sys/types.h>
54 #include <sys/limits.h>
55 #include <sys/resource.h>
70 #include "pathnames.h"
72 static void parse_input(int, char *[]);
73 static void prerun(int, char *[]);
74 static int prompt(void);
75 static void run(char **);
76 static void usage(void);
77 bool strnsubst(char **, const char *, const char *, size_t);
78 static pid_t xwait(int block, int *status);
79 static void xexit(const char *, const int);
80 static void waitchildren(const char *, int);
81 static void pids_init(void);
82 static int pids_empty(void);
83 static int pids_full(void);
84 static void pids_add(pid_t pid);
85 static int pids_remove(pid_t pid);
86 static int findslot(pid_t pid);
87 static int findfreeslot(void);
88 static void clearslot(int slot);
90 static char echo[] = _PATH_ECHO;
91 static char **av, **bxp, **ep, **endxp, **xp;
92 static char *argp, *bbp, *ebp, *inpline, *p, *replstr;
93 static const char *eofstr;
95 static int count, insingle, indouble, oflag, pflag, tflag, Rflag, rval, zflag;
96 static int cnt, Iflag, jfound, Lflag, Sflag, wasquoted, xflag;
97 static int curprocs, maxprocs;
98 static pid_t *childpids;
100 static volatile int childerr;
102 extern char **environ;
104 static const char *optstr = "+0E:I:J:L:n:oP:pR:S:s:rtx";
106 static const struct option long_options[] =
108 {"exit", no_argument, NULL, 'x'},
109 {"interactive", no_argument, NULL, 'p'},
110 {"max-args", required_argument, NULL, 'n'},
111 {"max-chars", required_argument, NULL, 's'},
112 {"max-procs", required_argument, NULL, 'P'},
113 {"no-run-if-empty", no_argument, NULL, 'r'},
114 {"null", no_argument, NULL, '0'},
115 {"verbose", no_argument, NULL, 't'},
117 {NULL, no_argument, NULL, 0},
121 main(int argc, char *argv[])
124 int ch, Jflag, nargs, nflag, nline;
129 inpline = replstr = NULL;
135 (void)setlocale(LC_ALL, "");
138 * POSIX.2 limits the exec line length to ARG_MAX - 2K. Running that
139 * caused some E2BIG errors, so it was changed to ARG_MAX - 4K. Given
140 * that the smallest argument is 2 bytes in length, this means that
141 * the number of arguments is limited to:
143 * (ARG_MAX - 4K - LENGTH(utility + arguments)) / 2.
145 * We arbitrarily limit the number of arguments to 5000. This is
146 * allowed by POSIX.2 as long as the resulting minimum exec line is
147 * at least LINE_MAX. Realloc'ing as necessary is possible, but
148 * probably not worthwhile.
151 if ((arg_max = sysconf(_SC_ARG_MAX)) == -1)
152 errx(1, "sysconf(_SC_ARG_MAX) failed");
153 nline = arg_max - 4 * 1024;
154 while (*ep != NULL) {
155 /* 1 byte for each '\0' */
156 nline -= strlen(*ep++) + 1 + sizeof(*ep);
159 while ((ch = getopt_long(argc, argv, optstr, long_options, NULL)) != -1)
163 eoflen = strlen(eofstr);
177 Lflag = (int)strtonum(optarg, 0, INT_MAX, &errstr);
179 errx(1, "-%c %s: %s", ch, optarg, errstr);
183 nargs = (int)strtonum(optarg, 1, INT_MAX, &errstr);
185 errx(1, "-%c %s: %s", ch, optarg, errstr);
191 maxprocs = (int)strtonum(optarg, 0, INT_MAX, &errstr);
193 errx(1, "-%c %s: %s", ch, optarg, errstr);
194 if (getrlimit(RLIMIT_NPROC, &rl) != 0)
195 errx(1, "getrlimit failed");
196 if (maxprocs == 0 || maxprocs > rl.rlim_cur)
197 maxprocs = rl.rlim_cur;
203 Rflag = (int)strtonum(optarg, 0, INT_MAX, &errstr);
205 errx(1, "-%c %s: %s", ch, optarg, errstr);
208 /* GNU compatibility */
211 Sflag = (int)strtonum(optarg, 0, INT_MAX, &errstr);
213 errx(1, "-%c %s: %s", ch, optarg, errstr);
216 nline = (int)strtonum(optarg, 0, INT_MAX, &errstr);
218 errx(1, "-%c %s: %s", ch, optarg, errstr);
248 if (replstr != NULL && *replstr == '\0')
249 errx(1, "replstr may not be empty");
254 * Allocate pointers for the utility name, the utility arguments,
255 * the maximum arguments to be read from stdin and the trailing
258 linelen = 1 + argc + nargs + 1;
259 if ((av = bxp = malloc(linelen * sizeof(char *))) == NULL)
260 errx(1, "malloc failed");
263 * Use the user's name for the utility as argv[0], just like the
264 * shell. Echo is the default. Set up pointers for the user's
268 cnt = strlen(*bxp++ = echo);
271 if (Jflag && strcmp(*argv, replstr) == 0) {
275 for (avj = argv; *avj; avj++)
276 cnt += strlen(*avj) + 1;
279 cnt += strlen(*bxp++ = *argv) + 1;
280 } while (*++argv != NULL);
284 * Set up begin/end/traversing pointers into the array. The -n
285 * count doesn't include the trailing NULL pointer, so the malloc
286 * added in an extra slot.
288 endxp = (xp = bxp) + nargs;
291 * Allocate buffer space for the arguments read from stdin and the
292 * trailing NULL. Buffer space is defined as the default or specified
293 * space, minus the length of the utility name and arguments. Set up
294 * begin/end/traversing pointers into the array. The -s count does
295 * include the trailing NULL, so the malloc didn't add in an extra
300 errx(1, "insufficient space for command");
302 if ((bbp = malloc((size_t)(nline + 1))) == NULL)
303 errx(1, "malloc failed");
304 ebp = (argp = p = bbp) + nline - 1;
306 parse_input(argc, argv);
310 parse_input(int argc, char *argv[])
317 switch (ch = getchar()) {
319 /* No arguments since last exec. */
321 waitchildren(*av, 1);
327 /* Quotes escape tabs and spaces. */
328 if (insingle || indouble || zflag)
334 * Increment 'count', so that nulls will be treated
335 * as end-of-line, as well as end-of-argument. This
336 * is needed so -0 works properly with -I and -L.
345 count++; /* Indicate end-of-line (used by -L) */
347 /* Quotes do not escape newlines. */
348 arg1: if (insingle || indouble) {
349 warnx("unterminated quote");
353 foundeof = eoflen != 0 && p - argp == eoflen &&
354 strncmp(argp, eofstr, eoflen) == 0;
356 /* Do not make empty args unless they are quoted */
357 if ((argp != p || wasquoted) && !foundeof) {
367 * If this string is not zero
368 * length, append a space for
369 * separation before the next
372 if ((curlen = strlen(inpline)))
373 strcat(inpline, " ");
377 * Allocate enough to hold what we will
378 * be holding in a second, and to append
379 * a space next time through, if we have
382 inpline = realloc(inpline, curlen + 2 +
384 if (inpline == NULL) {
385 warnx("realloc failed");
389 strcpy(inpline, argp);
391 strcat(inpline, argp);
396 * If max'd out on args or buffer, or reached EOF,
397 * run the command. If xflag and max'd out on buffer
398 * but not on args, object. Having reached the limit
399 * of input lines, as specified by -L is the same as
400 * maxing out on arguments.
402 if (xp == endxp || p > ebp || ch == EOF ||
403 (Lflag <= count && xflag) || foundeof) {
404 if (xflag && xp != endxp && p > ebp) {
405 warnx("insufficient space for arguments");
409 for (avj = argv; *avj; avj++)
413 if (ch == EOF || foundeof) {
414 waitchildren(*av, 1);
425 if (indouble || zflag)
427 insingle = !insingle;
431 if (insingle || zflag)
433 indouble = !indouble;
439 /* Backslash escapes anything, is escaped by quotes. */
440 if (!insingle && !indouble && (ch = getchar()) == EOF) {
441 warnx("backslash at EOF");
446 addch: if (p < ebp) {
451 /* If only one argument, not enough buffer space. */
453 warnx("insufficient space for argument");
456 /* Didn't hit argument limit, so if xflag object. */
458 warnx("insufficient space for arguments");
463 for (avj = argv; *avj; avj++)
469 memcpy(bbp, argp, (size_t)cnt);
470 p = (argp = bbp) + cnt;
477 * Do things necessary before run()'ing, such as -I substitution,
478 * and then call run().
481 prerun(int argc, char *argv[])
483 char **tmp, **tmp2, **avj;
488 if (argc == 0 || repls == 0) {
497 * Allocate memory to hold the argument list, and
498 * a NULL at the tail.
500 tmp = malloc((argc + 1) * sizeof(char *));
502 warnx("malloc failed");
508 * Save the first argument and iterate over it, we
509 * cannot do strnsubst() to it.
511 if ((*tmp++ = strdup(*avj++)) == NULL) {
512 warnx("strdup failed");
517 * For each argument to utility, if we have not used up
518 * the number of replacements we are allowed to do, and
519 * if the argument contains at least one occurrence of
520 * replstr, call strnsubst(), else just save the string.
521 * Iterations over elements of avj and tmp are done
526 if (repls && strstr(*tmp, replstr) != NULL) {
527 if (strnsubst(tmp++, replstr, inpline, (size_t)Sflag)) {
528 warnx("command line cannot be assembled, too long");
534 if ((*tmp = strdup(*tmp)) == NULL) {
535 warnx("strdup failed");
549 * Walk from the tail to the head, free along the way.
551 for (; tmp2 != tmp; tmp--)
554 * Now free the list itself.
559 * Free the input line buffer, if we have one.
561 if (inpline != NULL) {
575 * If the user wants to be notified of each command before it is
576 * executed, notify them. If they want the notification to be
577 * followed by a prompt, then prompt them.
579 if (tflag || pflag) {
580 (void)fprintf(stderr, "%s", *argv);
581 for (avec = argv + 1; *avec != NULL; ++avec)
582 (void)fprintf(stderr, " %s", *avec);
584 * If the user has asked to be prompted, do so.
588 * If they asked not to exec, return without execution
589 * but if they asked to, go to the execution. If we
590 * could not open their tty, break the switch and drop
591 * back to -t behaviour.
601 (void)fprintf(stderr, "\n");
602 (void)fflush(stderr);
606 switch (pid = vfork()) {
612 if ((fd = open(_PATH_TTY, O_RDONLY)) == -1)
613 err(1, "can't open /dev/tty");
615 fd = open(_PATH_DEVNULL, O_RDONLY);
617 if (fd > STDIN_FILENO) {
618 if (dup2(fd, STDIN_FILENO) != 0)
619 err(1, "can't dup2 to stdin");
622 execvp(argv[0], argv);
627 waitchildren(*argv, 0);
631 * Wait for a tracked child to exit and return its pid and exit status.
633 * Ignores (discards) all untracked child processes.
634 * Returns -1 and sets errno to ECHILD if no tracked children exist.
635 * If block is set, waits indefinitely for a child process to exit.
636 * If block is not set and no children have exited, returns 0 immediately.
639 xwait(int block, int *status) {
647 while ((pid = waitpid(-1, status, block ? 0 : WNOHANG)) > 0)
648 if (pids_remove(pid))
655 xexit(const char *name, const int exit_code) {
656 waitchildren(name, 1);
661 waitchildren(const char *name, int waitall)
667 while ((pid = xwait(waitall || pids_full(), &status)) > 0) {
669 * If we couldn't invoke the utility or if utility exited
670 * because of a signal or with a value of 255, warn (per
671 * POSIX), and then wait until all other children have
672 * exited before exiting 1-125. POSIX requires us to stop
673 * reading if child exits because of a signal or with 255,
674 * but it does not require us to exit immediately; waiting
675 * is preferable to orphaning.
677 if (childerr != 0 && cause_exit == 0) {
680 cause_exit = errno == ENOENT ? 127 : 126;
682 } else if (WIFSIGNALED(status)) {
683 waitall = cause_exit = 1;
684 warnx("%s: terminated with signal %d; aborting",
685 name, WTERMSIG(status));
686 } else if (WEXITSTATUS(status) == 255) {
687 waitall = cause_exit = 1;
688 warnx("%s: exited with status 255; aborting", name);
689 } else if (WEXITSTATUS(status))
695 if (pid == -1 && errno != ECHILD)
706 if ((childpids = malloc(maxprocs * sizeof(*childpids))) == NULL)
707 errx(1, "malloc failed");
709 for (i = 0; i < maxprocs; i++)
717 return (curprocs == 0);
724 return (curprocs >= maxprocs);
732 slot = findfreeslot();
733 childpids[slot] = pid;
738 pids_remove(pid_t pid)
742 if ((slot = findslot(pid)) < 0)
755 if ((slot = findslot(NOPID)) < 0)
756 errx(1, "internal error: no free pid slot");
765 for (slot = 0; slot < maxprocs; slot++)
766 if (childpids[slot] == pid)
775 childpids[slot] = NOPID;
779 * Prompt the user about running a command.
790 if ((ttyfp = fopen(_PATH_TTY, "r")) == NULL)
791 return (2); /* Indicate that the TTY failed to open. */
792 (void)fprintf(stderr, "?...");
793 (void)fflush(stderr);
794 if ((response = fgetln(ttyfp, &rsize)) == NULL ||
795 regcomp(&cre, nl_langinfo(YESEXPR), REG_EXTENDED) != 0) {
799 response[rsize - 1] = '\0';
800 match = regexec(&cre, response, 0, NULL, 0);
811 "usage: xargs [-0opt] [-E eofstr] [-I replstr [-R replacements] [-S replsize]]\n"
812 " [-J replstr] [-L number] [-n number [-x]] [-P maxprocs]\n"
813 " [-s size] [utility [argument ...]]\n");