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>
69 #include "pathnames.h"
71 static void parse_input(int, char *[]);
72 static void prerun(int, char *[]);
73 static int prompt(void);
74 static void run(char **);
75 static void usage(void);
76 void strnsubst(char **, const char *, const char *, size_t);
77 static pid_t xwait(int block, int *status);
78 static void xexit(const char *, const int);
79 static void waitchildren(const char *, int);
80 static void pids_init(void);
81 static int pids_empty(void);
82 static int pids_full(void);
83 static void pids_add(pid_t pid);
84 static int pids_remove(pid_t pid);
85 static int findslot(pid_t pid);
86 static int findfreeslot(void);
87 static void clearslot(int slot);
89 static char echo[] = _PATH_ECHO;
90 static char **av, **bxp, **ep, **endxp, **xp;
91 static char *argp, *bbp, *ebp, *inpline, *p, *replstr;
92 static const char *eofstr;
93 static int count, insingle, indouble, oflag, pflag, tflag, Rflag, rval, zflag;
94 static int cnt, Iflag, jfound, Lflag, Sflag, wasquoted, xflag;
95 static int curprocs, maxprocs;
96 static pid_t *childpids;
98 static volatile int childerr;
100 extern char **environ;
102 static const char *optstr = "+0E:I:J:L:n:oP:pR:S:s:rtx";
104 static const struct option long_options[] =
106 {"exit", no_argument, NULL, 'x'},
107 {"interactive", no_argument, NULL, 'p'},
108 {"max-args", required_argument, NULL, 'n'},
109 {"max-chars", required_argument, NULL, 's'},
110 {"max-procs", required_argument, NULL, 'P'},
111 {"no-run-if-empty", no_argument, NULL, 'r'},
112 {"null", no_argument, NULL, '0'},
113 {"verbose", no_argument, NULL, 't'},
115 {NULL, no_argument, NULL, 0},
119 main(int argc, char *argv[])
122 int ch, Jflag, nargs, nflag, nline;
128 inpline = replstr = NULL;
133 (void)setlocale(LC_ALL, "");
136 * POSIX.2 limits the exec line length to ARG_MAX - 2K. Running that
137 * caused some E2BIG errors, so it was changed to ARG_MAX - 4K. Given
138 * that the smallest argument is 2 bytes in length, this means that
139 * the number of arguments is limited to:
141 * (ARG_MAX - 4K - LENGTH(utility + arguments)) / 2.
143 * We arbitrarily limit the number of arguments to 5000. This is
144 * allowed by POSIX.2 as long as the resulting minimum exec line is
145 * at least LINE_MAX. Realloc'ing as necessary is possible, but
146 * probably not worthwhile.
149 if ((arg_max = sysconf(_SC_ARG_MAX)) == -1)
150 errx(1, "sysconf(_SC_ARG_MAX) failed");
151 nline = arg_max - 4 * 1024;
152 while (*ep != NULL) {
153 /* 1 byte for each '\0' */
154 nline -= strlen(*ep++) + 1 + sizeof(*ep);
157 while ((ch = getopt_long(argc, argv, optstr, long_options, NULL)) != -1)
174 Lflag = strtonum(optarg, 0, INT_MAX, &errstr);
176 errx(1, "-L %s: %s", optarg, errstr);
180 nargs = strtonum(optarg, 1, INT_MAX, &errstr);
182 errx(1, "-n %s: %s", optarg, errstr);
188 maxprocs = strtonum(optarg, 0, INT_MAX, &errstr);
190 errx(1, "-P %s: %s", optarg, errstr);
191 if (getrlimit(RLIMIT_NPROC, &rl) != 0)
192 errx(1, "getrlimit failed");
193 if (maxprocs == 0 || maxprocs > rl.rlim_cur)
194 maxprocs = rl.rlim_cur;
200 Rflag = strtol(optarg, &endptr, 10);
202 errx(1, "replacements must be a number");
205 /* GNU compatibility */
208 Sflag = strtoul(optarg, &endptr, 10);
210 errx(1, "replsize must be a number");
213 nline = strtonum(optarg, 0, INT_MAX, &errstr);
215 errx(1, "-s %s: %s", optarg, errstr);
245 if (replstr != NULL && *replstr == '\0')
246 errx(1, "replstr may not be empty");
251 * Allocate pointers for the utility name, the utility arguments,
252 * the maximum arguments to be read from stdin and the trailing
255 linelen = 1 + argc + nargs + 1;
256 if ((av = bxp = malloc(linelen * sizeof(char *))) == NULL)
257 errx(1, "malloc failed");
260 * Use the user's name for the utility as argv[0], just like the
261 * shell. Echo is the default. Set up pointers for the user's
265 cnt = strlen(*bxp++ = echo);
268 if (Jflag && strcmp(*argv, replstr) == 0) {
272 for (avj = argv; *avj; avj++)
273 cnt += strlen(*avj) + 1;
276 cnt += strlen(*bxp++ = *argv) + 1;
277 } while (*++argv != NULL);
281 * Set up begin/end/traversing pointers into the array. The -n
282 * count doesn't include the trailing NULL pointer, so the malloc
283 * added in an extra slot.
285 endxp = (xp = bxp) + nargs;
288 * Allocate buffer space for the arguments read from stdin and the
289 * trailing NULL. Buffer space is defined as the default or specified
290 * space, minus the length of the utility name and arguments. Set up
291 * begin/end/traversing pointers into the array. The -s count does
292 * include the trailing NULL, so the malloc didn't add in an extra
297 errx(1, "insufficient space for command");
299 if ((bbp = malloc((size_t)(nline + 1))) == NULL)
300 errx(1, "malloc failed");
301 ebp = (argp = p = bbp) + nline - 1;
303 parse_input(argc, argv);
307 parse_input(int argc, char *argv[])
314 switch (ch = getchar()) {
316 /* No arguments since last exec. */
322 /* Quotes escape tabs and spaces. */
323 if (insingle || indouble || zflag)
329 * Increment 'count', so that nulls will be treated
330 * as end-of-line, as well as end-of-argument. This
331 * is needed so -0 works properly with -I and -L.
340 count++; /* Indicate end-of-line (used by -L) */
342 /* Quotes do not escape newlines. */
343 arg1: if (insingle || indouble) {
344 warnx("unterminated quote");
348 foundeof = *eofstr != '\0' &&
349 strncmp(argp, eofstr, p - argp) == 0;
351 /* Do not make empty args unless they are quoted */
352 if ((argp != p || wasquoted) && !foundeof) {
362 * If this string is not zero
363 * length, append a space for
364 * separation before the next
367 if ((curlen = strlen(inpline)))
368 strcat(inpline, " ");
372 * Allocate enough to hold what we will
373 * be holding in a second, and to append
374 * a space next time through, if we have
377 inpline = realloc(inpline, curlen + 2 +
379 if (inpline == NULL) {
380 warnx("realloc failed");
384 strcpy(inpline, argp);
386 strcat(inpline, argp);
391 * If max'd out on args or buffer, or reached EOF,
392 * run the command. If xflag and max'd out on buffer
393 * but not on args, object. Having reached the limit
394 * of input lines, as specified by -L is the same as
395 * maxing out on arguments.
397 if (xp == endxp || p > ebp || ch == EOF ||
398 (Lflag <= count && xflag) || foundeof) {
399 if (xflag && xp != endxp && p > ebp) {
400 warnx("insufficient space for arguments");
404 for (avj = argv; *avj; avj++)
408 if (ch == EOF || foundeof)
418 if (indouble || zflag)
420 insingle = !insingle;
424 if (insingle || zflag)
426 indouble = !indouble;
432 /* Backslash escapes anything, is escaped by quotes. */
433 if (!insingle && !indouble && (ch = getchar()) == EOF) {
434 warnx("backslash at EOF");
439 addch: if (p < ebp) {
444 /* If only one argument, not enough buffer space. */
446 warnx("insufficient space for argument");
449 /* Didn't hit argument limit, so if xflag object. */
451 warnx("insufficient space for arguments");
456 for (avj = argv; *avj; avj++)
462 memcpy(bbp, argp, (size_t)cnt);
463 p = (argp = bbp) + cnt;
470 * Do things necessary before run()'ing, such as -I substitution,
471 * and then call run().
474 prerun(int argc, char *argv[])
476 char **tmp, **tmp2, **avj;
481 if (argc == 0 || repls == 0) {
490 * Allocate memory to hold the argument list, and
491 * a NULL at the tail.
493 tmp = malloc((argc + 1) * sizeof(char *));
495 warnx("malloc failed");
501 * Save the first argument and iterate over it, we
502 * cannot do strnsubst() to it.
504 if ((*tmp++ = strdup(*avj++)) == NULL) {
505 warnx("strdup failed");
510 * For each argument to utility, if we have not used up
511 * the number of replacements we are allowed to do, and
512 * if the argument contains at least one occurrence of
513 * replstr, call strnsubst(), else just save the string.
514 * Iterations over elements of avj and tmp are done
519 if (repls && strstr(*tmp, replstr) != NULL) {
520 strnsubst(tmp++, replstr, inpline, (size_t)Sflag);
524 if ((*tmp = strdup(*tmp)) == NULL) {
525 warnx("strdup failed");
539 * Walk from the tail to the head, free along the way.
541 for (; tmp2 != tmp; tmp--)
544 * Now free the list itself.
549 * Free the input line buffer, if we have one.
551 if (inpline != NULL) {
565 * If the user wants to be notified of each command before it is
566 * executed, notify them. If they want the notification to be
567 * followed by a prompt, then prompt them.
569 if (tflag || pflag) {
570 (void)fprintf(stderr, "%s", *argv);
571 for (avec = argv + 1; *avec != NULL; ++avec)
572 (void)fprintf(stderr, " %s", *avec);
574 * If the user has asked to be prompted, do so.
578 * If they asked not to exec, return without execution
579 * but if they asked to, go to the execution. If we
580 * could not open their tty, break the switch and drop
581 * back to -t behaviour.
591 (void)fprintf(stderr, "\n");
592 (void)fflush(stderr);
596 switch (pid = vfork()) {
602 if ((fd = open(_PATH_TTY, O_RDONLY)) == -1)
603 err(1, "can't open /dev/tty");
605 fd = open(_PATH_DEVNULL, O_RDONLY);
607 if (fd > STDIN_FILENO) {
608 if (dup2(fd, STDIN_FILENO) != 0)
609 err(1, "can't dup2 to stdin");
612 execvp(argv[0], argv);
617 waitchildren(*argv, 0);
621 * Wait for a tracked child to exit and return its pid and exit status.
623 * Ignores (discards) all untracked child processes.
624 * Returns -1 and sets errno to ECHILD if no tracked children exist.
625 * If block is set, waits indefinitely for a child process to exit.
626 * If block is not set and no children have exited, returns 0 immediately.
629 xwait(int block, int *status) {
637 while ((pid = waitpid(-1, status, block ? 0 : WNOHANG)) > 0)
638 if (pids_remove(pid))
645 xexit(const char *name, const int exit_code) {
646 waitchildren(name, 1);
651 waitchildren(const char *name, int waitall)
657 while ((pid = xwait(waitall || pids_full(), &status)) > 0) {
659 * If we couldn't invoke the utility or if utility exited
660 * because of a signal or with a value of 255, warn (per
661 * POSIX), and then wait until all other children have
662 * exited before exiting 1-125. POSIX requires us to stop
663 * reading if child exits because of a signal or with 255,
664 * but it does not require us to exit immediately; waiting
665 * is preferable to orphaning.
667 if (childerr != 0 && cause_exit == 0) {
670 cause_exit = errno == ENOENT ? 127 : 126;
672 } else if (WIFSIGNALED(status)) {
673 waitall = cause_exit = 1;
674 warnx("%s: terminated with signal %d; aborting",
675 name, WTERMSIG(status));
676 } else if (WEXITSTATUS(status) == 255) {
677 waitall = cause_exit = 1;
678 warnx("%s: exited with status 255; aborting", name);
679 } else if (WEXITSTATUS(status))
685 if (pid == -1 && errno != ECHILD)
696 if ((childpids = malloc(maxprocs * sizeof(*childpids))) == NULL)
697 errx(1, "malloc failed");
699 for (i = 0; i < maxprocs; i++)
707 return (curprocs == 0);
714 return (curprocs >= maxprocs);
722 slot = findfreeslot();
723 childpids[slot] = pid;
728 pids_remove(pid_t pid)
732 if ((slot = findslot(pid)) < 0)
745 if ((slot = findslot(NOPID)) < 0)
746 errx(1, "internal error: no free pid slot");
755 for (slot = 0; slot < maxprocs; slot++)
756 if (childpids[slot] == pid)
765 childpids[slot] = NOPID;
769 * Prompt the user about running a command.
780 if ((ttyfp = fopen(_PATH_TTY, "r")) == NULL)
781 return (2); /* Indicate that the TTY failed to open. */
782 (void)fprintf(stderr, "?...");
783 (void)fflush(stderr);
784 if ((response = fgetln(ttyfp, &rsize)) == NULL ||
785 regcomp(&cre, nl_langinfo(YESEXPR), REG_EXTENDED) != 0) {
789 response[rsize - 1] = '\0';
790 match = regexec(&cre, response, 0, NULL, 0);
801 "usage: xargs [-0opt] [-E eofstr] [-I replstr [-R replacements] [-S replsize]]\n"
802 " [-J replstr] [-L number] [-n number [-x]] [-P maxprocs]\n"
803 " [-s size] [utility [argument ...]]\n");