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;
130 inpline = replstr = NULL;
136 (void)setlocale(LC_ALL, "");
139 * POSIX.2 limits the exec line length to ARG_MAX - 2K. Running that
140 * caused some E2BIG errors, so it was changed to ARG_MAX - 4K. Given
141 * that the smallest argument is 2 bytes in length, this means that
142 * the number of arguments is limited to:
144 * (ARG_MAX - 4K - LENGTH(utility + arguments)) / 2.
146 * We arbitrarily limit the number of arguments to 5000. This is
147 * allowed by POSIX.2 as long as the resulting minimum exec line is
148 * at least LINE_MAX. Realloc'ing as necessary is possible, but
149 * probably not worthwhile.
152 if ((arg_max = sysconf(_SC_ARG_MAX)) == -1)
153 errx(1, "sysconf(_SC_ARG_MAX) failed");
154 nline = arg_max - 4 * 1024;
155 while (*ep != NULL) {
156 /* 1 byte for each '\0' */
157 nline -= strlen(*ep++) + 1 + sizeof(*ep);
160 while ((ch = getopt_long(argc, argv, optstr, long_options, NULL)) != -1)
164 eoflen = strlen(eofstr);
178 Lflag = strtonum(optarg, 0, INT_MAX, &errstr);
180 errx(1, "-L %s: %s", optarg, errstr);
184 nargs = strtonum(optarg, 1, INT_MAX, &errstr);
186 errx(1, "-n %s: %s", optarg, errstr);
192 maxprocs = strtonum(optarg, 0, INT_MAX, &errstr);
194 errx(1, "-P %s: %s", optarg, errstr);
195 if (getrlimit(RLIMIT_NPROC, &rl) != 0)
196 errx(1, "getrlimit failed");
197 if (maxprocs == 0 || maxprocs > rl.rlim_cur)
198 maxprocs = rl.rlim_cur;
204 Rflag = strtol(optarg, &endptr, 10);
206 errx(1, "replacements must be a number");
209 /* GNU compatibility */
212 Sflag = strtoul(optarg, &endptr, 10);
214 errx(1, "replsize must be a number");
217 nline = strtonum(optarg, 0, INT_MAX, &errstr);
219 errx(1, "-s %s: %s", optarg, errstr);
249 if (replstr != NULL && *replstr == '\0')
250 errx(1, "replstr may not be empty");
255 * Allocate pointers for the utility name, the utility arguments,
256 * the maximum arguments to be read from stdin and the trailing
259 linelen = 1 + argc + nargs + 1;
260 if ((av = bxp = malloc(linelen * sizeof(char *))) == NULL)
261 errx(1, "malloc failed");
264 * Use the user's name for the utility as argv[0], just like the
265 * shell. Echo is the default. Set up pointers for the user's
269 cnt = strlen(*bxp++ = echo);
272 if (Jflag && strcmp(*argv, replstr) == 0) {
276 for (avj = argv; *avj; avj++)
277 cnt += strlen(*avj) + 1;
280 cnt += strlen(*bxp++ = *argv) + 1;
281 } while (*++argv != NULL);
285 * Set up begin/end/traversing pointers into the array. The -n
286 * count doesn't include the trailing NULL pointer, so the malloc
287 * added in an extra slot.
289 endxp = (xp = bxp) + nargs;
292 * Allocate buffer space for the arguments read from stdin and the
293 * trailing NULL. Buffer space is defined as the default or specified
294 * space, minus the length of the utility name and arguments. Set up
295 * begin/end/traversing pointers into the array. The -s count does
296 * include the trailing NULL, so the malloc didn't add in an extra
301 errx(1, "insufficient space for command");
303 if ((bbp = malloc((size_t)(nline + 1))) == NULL)
304 errx(1, "malloc failed");
305 ebp = (argp = p = bbp) + nline - 1;
307 parse_input(argc, argv);
311 parse_input(int argc, char *argv[])
318 switch (ch = getchar()) {
320 /* No arguments since last exec. */
322 waitchildren(*av, 1);
328 /* Quotes escape tabs and spaces. */
329 if (insingle || indouble || zflag)
335 * Increment 'count', so that nulls will be treated
336 * as end-of-line, as well as end-of-argument. This
337 * is needed so -0 works properly with -I and -L.
346 count++; /* Indicate end-of-line (used by -L) */
348 /* Quotes do not escape newlines. */
349 arg1: if (insingle || indouble) {
350 warnx("unterminated quote");
354 foundeof = eoflen != 0 && p - argp == eoflen &&
355 strncmp(argp, eofstr, eoflen) == 0;
357 /* Do not make empty args unless they are quoted */
358 if ((argp != p || wasquoted) && !foundeof) {
368 * If this string is not zero
369 * length, append a space for
370 * separation before the next
373 if ((curlen = strlen(inpline)))
374 strcat(inpline, " ");
378 * Allocate enough to hold what we will
379 * be holding in a second, and to append
380 * a space next time through, if we have
383 inpline = realloc(inpline, curlen + 2 +
385 if (inpline == NULL) {
386 warnx("realloc failed");
390 strcpy(inpline, argp);
392 strcat(inpline, argp);
397 * If max'd out on args or buffer, or reached EOF,
398 * run the command. If xflag and max'd out on buffer
399 * but not on args, object. Having reached the limit
400 * of input lines, as specified by -L is the same as
401 * maxing out on arguments.
403 if (xp == endxp || p > ebp || ch == EOF ||
404 (Lflag <= count && xflag) || foundeof) {
405 if (xflag && xp != endxp && p > ebp) {
406 warnx("insufficient space for arguments");
410 for (avj = argv; *avj; avj++)
414 if (ch == EOF || foundeof) {
415 waitchildren(*av, 1);
426 if (indouble || zflag)
428 insingle = !insingle;
432 if (insingle || zflag)
434 indouble = !indouble;
440 /* Backslash escapes anything, is escaped by quotes. */
441 if (!insingle && !indouble && (ch = getchar()) == EOF) {
442 warnx("backslash at EOF");
447 addch: if (p < ebp) {
452 /* If only one argument, not enough buffer space. */
454 warnx("insufficient space for argument");
457 /* Didn't hit argument limit, so if xflag object. */
459 warnx("insufficient space for arguments");
464 for (avj = argv; *avj; avj++)
470 memcpy(bbp, argp, (size_t)cnt);
471 p = (argp = bbp) + cnt;
478 * Do things necessary before run()'ing, such as -I substitution,
479 * and then call run().
482 prerun(int argc, char *argv[])
484 char **tmp, **tmp2, **avj;
489 if (argc == 0 || repls == 0) {
498 * Allocate memory to hold the argument list, and
499 * a NULL at the tail.
501 tmp = malloc((argc + 1) * sizeof(char *));
503 warnx("malloc failed");
509 * Save the first argument and iterate over it, we
510 * cannot do strnsubst() to it.
512 if ((*tmp++ = strdup(*avj++)) == NULL) {
513 warnx("strdup failed");
518 * For each argument to utility, if we have not used up
519 * the number of replacements we are allowed to do, and
520 * if the argument contains at least one occurrence of
521 * replstr, call strnsubst(), else just save the string.
522 * Iterations over elements of avj and tmp are done
527 if (repls && strstr(*tmp, replstr) != NULL) {
528 if (strnsubst(tmp++, replstr, inpline, (size_t)Sflag)) {
529 warnx("comamnd line cannot be assembled, too long");
535 if ((*tmp = strdup(*tmp)) == NULL) {
536 warnx("strdup failed");
550 * Walk from the tail to the head, free along the way.
552 for (; tmp2 != tmp; tmp--)
555 * Now free the list itself.
560 * Free the input line buffer, if we have one.
562 if (inpline != NULL) {
576 * If the user wants to be notified of each command before it is
577 * executed, notify them. If they want the notification to be
578 * followed by a prompt, then prompt them.
580 if (tflag || pflag) {
581 (void)fprintf(stderr, "%s", *argv);
582 for (avec = argv + 1; *avec != NULL; ++avec)
583 (void)fprintf(stderr, " %s", *avec);
585 * If the user has asked to be prompted, do so.
589 * If they asked not to exec, return without execution
590 * but if they asked to, go to the execution. If we
591 * could not open their tty, break the switch and drop
592 * back to -t behaviour.
602 (void)fprintf(stderr, "\n");
603 (void)fflush(stderr);
607 switch (pid = vfork()) {
613 if ((fd = open(_PATH_TTY, O_RDONLY)) == -1)
614 err(1, "can't open /dev/tty");
616 fd = open(_PATH_DEVNULL, O_RDONLY);
618 if (fd > STDIN_FILENO) {
619 if (dup2(fd, STDIN_FILENO) != 0)
620 err(1, "can't dup2 to stdin");
623 execvp(argv[0], argv);
628 waitchildren(*argv, 0);
632 * Wait for a tracked child to exit and return its pid and exit status.
634 * Ignores (discards) all untracked child processes.
635 * Returns -1 and sets errno to ECHILD if no tracked children exist.
636 * If block is set, waits indefinitely for a child process to exit.
637 * If block is not set and no children have exited, returns 0 immediately.
640 xwait(int block, int *status) {
648 while ((pid = waitpid(-1, status, block ? 0 : WNOHANG)) > 0)
649 if (pids_remove(pid))
656 xexit(const char *name, const int exit_code) {
657 waitchildren(name, 1);
662 waitchildren(const char *name, int waitall)
668 while ((pid = xwait(waitall || pids_full(), &status)) > 0) {
670 * If we couldn't invoke the utility or if utility exited
671 * because of a signal or with a value of 255, warn (per
672 * POSIX), and then wait until all other children have
673 * exited before exiting 1-125. POSIX requires us to stop
674 * reading if child exits because of a signal or with 255,
675 * but it does not require us to exit immediately; waiting
676 * is preferable to orphaning.
678 if (childerr != 0 && cause_exit == 0) {
681 cause_exit = errno == ENOENT ? 127 : 126;
683 } else if (WIFSIGNALED(status)) {
684 waitall = cause_exit = 1;
685 warnx("%s: terminated with signal %d; aborting",
686 name, WTERMSIG(status));
687 } else if (WEXITSTATUS(status) == 255) {
688 waitall = cause_exit = 1;
689 warnx("%s: exited with status 255; aborting", name);
690 } else if (WEXITSTATUS(status))
696 if (pid == -1 && errno != ECHILD)
707 if ((childpids = malloc(maxprocs * sizeof(*childpids))) == NULL)
708 errx(1, "malloc failed");
710 for (i = 0; i < maxprocs; i++)
718 return (curprocs == 0);
725 return (curprocs >= maxprocs);
733 slot = findfreeslot();
734 childpids[slot] = pid;
739 pids_remove(pid_t pid)
743 if ((slot = findslot(pid)) < 0)
756 if ((slot = findslot(NOPID)) < 0)
757 errx(1, "internal error: no free pid slot");
766 for (slot = 0; slot < maxprocs; slot++)
767 if (childpids[slot] == pid)
776 childpids[slot] = NOPID;
780 * Prompt the user about running a command.
791 if ((ttyfp = fopen(_PATH_TTY, "r")) == NULL)
792 return (2); /* Indicate that the TTY failed to open. */
793 (void)fprintf(stderr, "?...");
794 (void)fflush(stderr);
795 if ((response = fgetln(ttyfp, &rsize)) == NULL ||
796 regcomp(&cre, nl_langinfo(YESEXPR), REG_EXTENDED) != 0) {
800 response[rsize - 1] = '\0';
801 match = regexec(&cre, response, 0, NULL, 0);
812 "usage: xargs [-0opt] [-E eofstr] [-I replstr [-R replacements] [-S replsize]]\n"
813 " [-J replstr] [-L number] [-n number [-x]] [-P maxprocs]\n"
814 " [-s size] [utility [argument ...]]\n");