2 * Copyright (c) 1990, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * $xMach: xargs.c,v 1.6 2002/02/23 05:27:47 tim Exp $
41 static const char copyright[] =
42 "@(#) Copyright (c) 1990, 1993\n\
43 The Regents of the University of California. All rights reserved.\n";
47 static char sccsid[] = "@(#)xargs.c 8.1 (Berkeley) 6/6/93";
50 #include <sys/cdefs.h>
51 __FBSDID("$FreeBSD$");
53 #include <sys/param.h>
68 #include "pathnames.h"
70 static void parse_input(int, char *[]);
71 static void prerun(int, char *[]);
72 static int prompt(void);
73 static void run(char **);
74 static void usage(void);
75 void strnsubst(char **, const char *, const char *, size_t);
76 static pid_t xwait(int block, int *status);
77 static void waitchildren(const char *, int);
78 static void pids_init(void);
79 static int pids_empty(void);
80 static int pids_full(void);
81 static void pids_add(pid_t pid);
82 static int pids_remove(pid_t pid);
83 static int findslot(pid_t pid);
84 static int findfreeslot(void);
85 static void clearslot(int slot);
87 static char echo[] = _PATH_ECHO;
88 static char **av, **bxp, **ep, **endxp, **xp;
89 static char *argp, *bbp, *ebp, *inpline, *p, *replstr;
90 static const char *eofstr;
91 static int count, insingle, indouble, oflag, pflag, tflag, Rflag, rval, zflag;
92 static int cnt, Iflag, jfound, Lflag, Sflag, wasquoted, xflag;
93 static int curprocs, maxprocs;
94 static pid_t *childpids;
96 static volatile int childerr;
98 extern char **environ;
101 main(int argc, char *argv[])
104 int ch, Jflag, nargs, nflag, nline;
108 inpline = replstr = NULL;
113 (void)setlocale(LC_ALL, "");
116 * POSIX.2 limits the exec line length to ARG_MAX - 2K. Running that
117 * caused some E2BIG errors, so it was changed to ARG_MAX - 4K. Given
118 * that the smallest argument is 2 bytes in length, this means that
119 * the number of arguments is limited to:
121 * (ARG_MAX - 4K - LENGTH(utility + arguments)) / 2.
123 * We arbitrarily limit the number of arguments to 5000. This is
124 * allowed by POSIX.2 as long as the resulting minimum exec line is
125 * at least LINE_MAX. Realloc'ing as necessary is possible, but
126 * probably not worthwhile.
129 if ((arg_max = sysconf(_SC_ARG_MAX)) == -1)
130 errx(1, "sysconf(_SC_ARG_MAX) failed");
131 nline = arg_max - 4 * 1024;
132 while (*ep != NULL) {
133 /* 1 byte for each '\0' */
134 nline -= strlen(*ep++) + 1 + sizeof(*ep);
137 while ((ch = getopt(argc, argv, "0E:I:J:L:n:oP:pR:S:s:rtx")) != -1)
154 Lflag = atoi(optarg);
158 if ((nargs = atoi(optarg)) <= 0)
159 errx(1, "illegal argument count");
165 if ((maxprocs = atoi(optarg)) <= 0)
166 errx(1, "max. processes must be >0");
172 Rflag = strtol(optarg, &endptr, 10);
174 errx(1, "replacements must be a number");
177 /* GNU compatibility */
180 Sflag = strtoul(optarg, &endptr, 10);
182 errx(1, "replsize must be a number");
185 nline = atoi(optarg);
215 if (replstr != NULL && *replstr == '\0')
216 errx(1, "replstr may not be empty");
221 * Allocate pointers for the utility name, the utility arguments,
222 * the maximum arguments to be read from stdin and the trailing
225 linelen = 1 + argc + nargs + 1;
226 if ((av = bxp = malloc(linelen * sizeof(char **))) == NULL)
227 errx(1, "malloc failed");
230 * Use the user's name for the utility as argv[0], just like the
231 * shell. Echo is the default. Set up pointers for the user's
235 cnt = strlen(*bxp++ = echo);
238 if (Jflag && strcmp(*argv, replstr) == 0) {
242 for (avj = argv; *avj; avj++)
243 cnt += strlen(*avj) + 1;
246 cnt += strlen(*bxp++ = *argv) + 1;
247 } while (*++argv != NULL);
251 * Set up begin/end/traversing pointers into the array. The -n
252 * count doesn't include the trailing NULL pointer, so the malloc
253 * added in an extra slot.
255 endxp = (xp = bxp) + nargs;
258 * Allocate buffer space for the arguments read from stdin and the
259 * trailing NULL. Buffer space is defined as the default or specified
260 * space, minus the length of the utility name and arguments. Set up
261 * begin/end/traversing pointers into the array. The -s count does
262 * include the trailing NULL, so the malloc didn't add in an extra
267 errx(1, "insufficient space for command");
269 if ((bbp = malloc((size_t)(nline + 1))) == NULL)
270 errx(1, "malloc failed");
271 ebp = (argp = p = bbp) + nline - 1;
273 parse_input(argc, argv);
277 parse_input(int argc, char *argv[])
284 switch (ch = getchar()) {
286 /* No arguments since last exec. */
288 waitchildren(*argv, 1);
294 /* Quotes escape tabs and spaces. */
295 if (insingle || indouble || zflag)
301 * Increment 'count', so that nulls will be treated
302 * as end-of-line, as well as end-of-argument. This
303 * is needed so -0 works properly with -I and -L.
312 count++; /* Indicate end-of-line (used by -L) */
314 /* Quotes do not escape newlines. */
315 arg1: if (insingle || indouble)
316 errx(1, "unterminated quote");
318 foundeof = *eofstr != '\0' &&
319 strncmp(argp, eofstr, p - argp) == 0;
321 /* Do not make empty args unless they are quoted */
322 if ((argp != p || wasquoted) && !foundeof) {
332 * If this string is not zero
333 * length, append a space for
334 * separation before the next
337 if ((curlen = strlen(inpline)))
338 strcat(inpline, " ");
342 * Allocate enough to hold what we will
343 * be holding in a second, and to append
344 * a space next time through, if we have
347 inpline = realloc(inpline, curlen + 2 +
350 errx(1, "realloc failed");
352 strcpy(inpline, argp);
354 strcat(inpline, argp);
359 * If max'd out on args or buffer, or reached EOF,
360 * run the command. If xflag and max'd out on buffer
361 * but not on args, object. Having reached the limit
362 * of input lines, as specified by -L is the same as
363 * maxing out on arguments.
365 if (xp == endxp || p > ebp || ch == EOF ||
366 (Lflag <= count && xflag) || foundeof) {
367 if (xflag && xp != endxp && p > ebp)
368 errx(1, "insufficient space for arguments");
370 for (avj = argv; *avj; avj++)
374 if (ch == EOF || foundeof) {
375 waitchildren(*argv, 1);
386 if (indouble || zflag)
388 insingle = !insingle;
392 if (insingle || zflag)
394 indouble = !indouble;
400 /* Backslash escapes anything, is escaped by quotes. */
401 if (!insingle && !indouble && (ch = getchar()) == EOF)
402 errx(1, "backslash at EOF");
405 addch: if (p < ebp) {
410 /* If only one argument, not enough buffer space. */
412 errx(1, "insufficient space for argument");
413 /* Didn't hit argument limit, so if xflag object. */
415 errx(1, "insufficient space for arguments");
418 for (avj = argv; *avj; avj++)
424 memcpy(bbp, argp, (size_t)cnt);
425 p = (argp = bbp) + cnt;
432 * Do things necessary before run()'ing, such as -I substitution,
433 * and then call run().
436 prerun(int argc, char *argv[])
438 char **tmp, **tmp2, **avj;
443 if (argc == 0 || repls == 0) {
452 * Allocate memory to hold the argument list, and
453 * a NULL at the tail.
455 tmp = malloc((argc + 1) * sizeof(char**));
457 errx(1, "malloc failed");
461 * Save the first argument and iterate over it, we
462 * cannot do strnsubst() to it.
464 if ((*tmp++ = strdup(*avj++)) == NULL)
465 errx(1, "strdup failed");
468 * For each argument to utility, if we have not used up
469 * the number of replacements we are allowed to do, and
470 * if the argument contains at least one occurrence of
471 * replstr, call strnsubst(), else just save the string.
472 * Iterations over elements of avj and tmp are done
477 if (repls && strstr(*tmp, replstr) != NULL) {
478 strnsubst(tmp++, replstr, inpline, (size_t)Sflag);
482 if ((*tmp = strdup(*tmp)) == NULL)
483 errx(1, "strdup failed");
495 * Walk from the tail to the head, free along the way.
497 for (; tmp2 != tmp; tmp--)
500 * Now free the list itself.
505 * Free the input line buffer, if we have one.
507 if (inpline != NULL) {
521 * If the user wants to be notified of each command before it is
522 * executed, notify them. If they want the notification to be
523 * followed by a prompt, then prompt them.
525 if (tflag || pflag) {
526 (void)fprintf(stderr, "%s", *argv);
527 for (avec = argv + 1; *avec != NULL; ++avec)
528 (void)fprintf(stderr, " %s", *avec);
530 * If the user has asked to be prompted, do so.
534 * If they asked not to exec, return without execution
535 * but if they asked to, go to the execution. If we
536 * could not open their tty, break the switch and drop
537 * back to -t behaviour.
547 (void)fprintf(stderr, "\n");
548 (void)fflush(stderr);
552 switch (pid = vfork()) {
557 if ((fd = open(_PATH_TTY, O_RDONLY)) == -1)
558 err(1, "can't open /dev/tty");
560 fd = open(_PATH_DEVNULL, O_RDONLY);
562 if (fd > STDIN_FILENO) {
563 if (dup2(fd, STDIN_FILENO) != 0)
564 err(1, "can't dup2 to stdin");
567 execvp(argv[0], argv);
572 waitchildren(*argv, 0);
576 * Wait for a tracked child to exit and return its pid and exit status.
578 * Ignores (discards) all untracked child processes.
579 * Returns -1 and sets errno to ECHILD if no tracked children exist.
580 * If block is set, waits indefinitely for a child process to exit.
581 * If block is not set and no children have exited, returns 0 immediately.
584 xwait(int block, int *status) {
592 while ((pid = waitpid(-1, status, block ? 0 : WNOHANG)) > 0)
593 if (pids_remove(pid))
600 waitchildren(const char *name, int waitall)
605 while ((pid = xwait(waitall || pids_full(), &status)) > 0) {
606 /* If we couldn't invoke the utility, exit. */
609 err(errno == ENOENT ? 127 : 126, "%s", name);
612 * If utility signaled or exited with a value of 255,
615 if (WIFSIGNALED(status) || WEXITSTATUS(status) == 255)
617 if (WEXITSTATUS(status))
621 if (pid == -1 && errno != ECHILD)
632 if ((childpids = malloc(maxprocs * sizeof(*childpids))) == NULL)
633 errx(1, "malloc failed");
635 for (i = 0; i < maxprocs; i++)
642 return (curprocs == 0);
648 return (curprocs >= maxprocs);
656 slot = findfreeslot();
657 childpids[slot] = pid;
662 pids_remove(pid_t pid)
666 if ((slot = findslot(pid)) < 0)
679 if ((slot = findslot(NOPID)) < 0)
680 errx(1, "internal error: no free pid slot");
690 for (slot = 0; slot < maxprocs; slot++)
691 if (childpids[slot] == pid)
700 childpids[slot] = NOPID;
704 * Prompt the user about running a command.
715 if ((ttyfp = fopen(_PATH_TTY, "r")) == NULL)
716 return (2); /* Indicate that the TTY failed to open. */
717 (void)fprintf(stderr, "?...");
718 (void)fflush(stderr);
719 if ((response = fgetln(ttyfp, &rsize)) == NULL ||
720 regcomp(&cre, nl_langinfo(YESEXPR), REG_BASIC) != 0) {
724 response[rsize - 1] = '\0';
725 match = regexec(&cre, response, 0, NULL, 0);
735 "usage: xargs [-0opt] [-E eofstr] [-I replstr [-R replacements] [-S replsize]]\n"
736 " [-J replstr] [-L number] [-n number [-x]] [-P maxprocs]\n"
737 " [-s size] [utility [argument ...]]\n");