1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1990, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * John B. Roll Jr.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
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.
21 *
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
32 * SUCH DAMAGE.
33 *
34 * $xMach: xargs.c,v 1.6 2002/02/23 05:27:47 tim Exp $
35 *
36 * @(#) Copyright (c) 1990, 1993 The Regents of the University of California. All rights reserved.
37 * @(#)xargs.c 8.1 (Berkeley) 6/6/93
38 * $FreeBSD: head/usr.bin/xargs/xargs.c 359596 2020-04-03 14:03:58Z markj $
39 */
40
41 #include <sys/types.h>
42 #include <sys/wait.h>
43 #include <sys/time.h>
44 #include <sys/limits.h>
45 #include <sys/resource.h>
46 #include <err.h>
47 #include <errno.h>
48 #include <fcntl.h>
49 #include <getopt.h>
50 #include <langinfo.h>
51 #include <limits.h>
52 #include <locale.h>
53 #include <paths.h>
54 #include <regex.h>
55 #include <stdbool.h>
56 #include <signal.h>
57 #include <stdint.h>
58 #include <stdio.h>
59 #include <stdlib.h>
60 #include <string.h>
61 #include <unistd.h>
62
63 #include "pathnames.h"
64
65 static void parse_input(int, char *[]);
66 static void prerun(int, char *[]);
67 #ifndef BOOTSTRAPPING
68 static int prompt(void);
69 #endif
70 static void run(char **);
71 static void usage(void);
72 bool strnsubst(char **, const char *, const char *, size_t);
73 static pid_t xwait(int block, int *status);
74 static void xexit(const char *, const int);
75 static void waitchildren(const char *, int);
76 static void pids_init(void);
77 static int pids_empty(void);
78 static int pids_full(void);
79 static void pids_add(pid_t pid);
80 static int pids_remove(pid_t pid);
81 static int findslot(pid_t pid);
82 static int findfreeslot(void);
83 static void clearslot(int slot);
84
85 static char echo[] = _PATH_ECHO;
86 static char **av, **bxp, **ep, **endxp, **xp;
87 static char *argp, *bbp, *ebp, *inpline, *p, *replstr;
88 static const char *eofstr;
89 static int count, insingle, indouble, oflag, pflag, tflag, Rflag, rval, zflag;
90 static int cnt, Iflag, jfound, Lflag, Sflag, wasquoted, xflag;
91 static int curprocs, maxprocs;
92 static pid_t *childpids;
93
94 static volatile int childerr;
95
96 extern char **environ;
97
98 static const char *optstr = "+0E:I:J:L:n:oP:pR:S:s:rtx";
99
100 static const struct option long_options[] =
101 {
102 {"exit", no_argument, NULL, 'x'},
103 {"interactive", no_argument, NULL, 'p'},
104 {"max-args", required_argument, NULL, 'n'},
105 {"max-chars", required_argument, NULL, 's'},
106 {"max-procs", required_argument, NULL, 'P'},
107 {"no-run-if-empty", no_argument, NULL, 'r'},
108 {"null", no_argument, NULL, '0'},
109 {"verbose", no_argument, NULL, 't'},
110
111 {NULL, no_argument, NULL, 0},
112 };
113
114 int
main(int argc,char * argv[])115 main(int argc, char *argv[])
116 {
117 long arg_max;
118 int ch, Jflag, nargs, nflag, nline;
119 size_t linelen;
120 struct rlimit rl;
121 char *endptr;
122 const char *errstr;
123
124 inpline = replstr = NULL;
125 ep = environ;
126 eofstr = "";
127 Jflag = nflag = 0;
128
129 (void)setlocale(LC_ALL, "");
130
131 /*
132 * POSIX.2 limits the exec line length to ARG_MAX - 2K. Running that
133 * caused some E2BIG errors, so it was changed to ARG_MAX - 4K. Given
134 * that the smallest argument is 2 bytes in length, this means that
135 * the number of arguments is limited to:
136 *
137 * (ARG_MAX - 4K - LENGTH(utility + arguments)) / 2.
138 *
139 * We arbitrarily limit the number of arguments to 5000. This is
140 * allowed by POSIX.2 as long as the resulting minimum exec line is
141 * at least LINE_MAX. Realloc'ing as necessary is possible, but
142 * probably not worthwhile.
143 */
144 nargs = 5000;
145 if ((arg_max = sysconf(_SC_ARG_MAX)) == -1)
146 errx(1, "sysconf(_SC_ARG_MAX) failed");
147 if (arg_max > INT32_MAX) {
148 /* cap arg_max to int32_t */
149 arg_max = INT32_MAX;
150 }
151 nline = arg_max - 4 * 1024;
152 while (*ep != NULL) {
153 /* 1 byte for each '\0' */
154 nline -= strlen(*ep++) + 1 + sizeof(*ep);
155 }
156 maxprocs = 1;
157 while ((ch = getopt_long(argc, argv, optstr, long_options, NULL)) != -1)
158 switch (ch) {
159 case 'E':
160 eofstr = optarg;
161 break;
162 case 'I':
163 Jflag = 0;
164 Iflag = 1;
165 Lflag = 1;
166 replstr = optarg;
167 break;
168 case 'J':
169 Iflag = 0;
170 Jflag = 1;
171 replstr = optarg;
172 break;
173 case 'L':
174 Lflag = strtonum(optarg, 0, INT_MAX, &errstr);
175 if (errstr)
176 errx(1, "-L %s: %s", optarg, errstr);
177 break;
178 case 'n':
179 nflag = 1;
180 nargs = strtonum(optarg, 1, INT_MAX, &errstr);
181 if (errstr)
182 errx(1, "-n %s: %s", optarg, errstr);
183 break;
184 case 'o':
185 oflag = 1;
186 break;
187 case 'P':
188 maxprocs = strtonum(optarg, 0, INT_MAX, &errstr);
189 if (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;
195 break;
196 case 'p':
197 #ifndef BOOTSTRAPPING
198 pflag = 1;
199 #endif
200 break;
201 case 'R':
202 Rflag = strtol(optarg, &endptr, 10);
203 if (*endptr != '\0')
204 errx(1, "replacements must be a number");
205 break;
206 case 'r':
207 /* GNU compatibility */
208 break;
209 case 'S':
210 Sflag = strtoul(optarg, &endptr, 10);
211 if (*endptr != '\0')
212 errx(1, "replsize must be a number");
213 break;
214 case 's':
215 nline = strtonum(optarg, 0, INT_MAX, &errstr);
216 if (errstr)
217 errx(1, "-s %s: %s", optarg, errstr);
218 break;
219 case 't':
220 tflag = 1;
221 break;
222 case 'x':
223 xflag = 1;
224 break;
225 case '0':
226 zflag = 1;
227 break;
228 case '?':
229 default:
230 usage();
231 }
232 argc -= optind;
233 argv += optind;
234
235 if (!Iflag && Rflag)
236 usage();
237 if (!Iflag && Sflag)
238 usage();
239 if (Iflag && !Rflag)
240 Rflag = 5;
241 if (Iflag && !Sflag)
242 Sflag = 255;
243 if (xflag && !nflag)
244 usage();
245 if (Iflag || Lflag)
246 xflag = 1;
247 if (replstr != NULL && *replstr == '\0')
248 errx(1, "replstr may not be empty");
249
250 pids_init();
251
252 /*
253 * Allocate pointers for the utility name, the utility arguments,
254 * the maximum arguments to be read from stdin and the trailing
255 * NULL.
256 */
257 linelen = 1 + argc + nargs + 1;
258 if ((av = bxp = malloc(linelen * sizeof(char *))) == NULL)
259 errx(1, "malloc failed");
260
261 /*
262 * Use the user's name for the utility as argv[0], just like the
263 * shell. Echo is the default. Set up pointers for the user's
264 * arguments.
265 */
266 if (*argv == NULL)
267 cnt = strlen(*bxp++ = echo);
268 else {
269 do {
270 if (Jflag && strcmp(*argv, replstr) == 0) {
271 char **avj;
272 jfound = 1;
273 argv++;
274 for (avj = argv; *avj; avj++)
275 cnt += strlen(*avj) + 1;
276 break;
277 }
278 cnt += strlen(*bxp++ = *argv) + 1;
279 } while (*++argv != NULL);
280 }
281
282 /*
283 * Set up begin/end/traversing pointers into the array. The -n
284 * count doesn't include the trailing NULL pointer, so the malloc
285 * added in an extra slot.
286 */
287 endxp = (xp = bxp) + nargs;
288
289 /*
290 * Allocate buffer space for the arguments read from stdin and the
291 * trailing NULL. Buffer space is defined as the default or specified
292 * space, minus the length of the utility name and arguments. Set up
293 * begin/end/traversing pointers into the array. The -s count does
294 * include the trailing NULL, so the malloc didn't add in an extra
295 * slot.
296 */
297 nline -= cnt;
298 if (nline <= 0)
299 errx(1, "insufficient space for command");
300
301 if ((bbp = malloc((size_t)(nline + 1))) == NULL)
302 errx(1, "malloc failed");
303 ebp = (argp = p = bbp) + nline - 1;
304 for (;;)
305 parse_input(argc, argv);
306 }
307
308 static void
parse_input(int argc,char * argv[])309 parse_input(int argc, char *argv[])
310 {
311 int ch, foundeof;
312 char **avj;
313
314 foundeof = 0;
315
316 switch (ch = getchar()) {
317 case EOF:
318 /* No arguments since last exec. */
319 if (p == bbp) {
320 waitchildren(*av, 1);
321 exit(rval);
322 }
323 goto arg1;
324 case ' ':
325 case '\t':
326 /* Quotes escape tabs and spaces. */
327 if (insingle || indouble || zflag)
328 goto addch;
329 goto arg2;
330 case '\0':
331 if (zflag) {
332 /*
333 * Increment 'count', so that nulls will be treated
334 * as end-of-line, as well as end-of-argument. This
335 * is needed so -0 works properly with -I and -L.
336 */
337 count++;
338 goto arg2;
339 }
340 goto addch;
341 case '\n':
342 if (zflag)
343 goto addch;
344 count++; /* Indicate end-of-line (used by -L) */
345
346 /* Quotes do not escape newlines. */
347 arg1: if (insingle || indouble) {
348 warnx("unterminated quote");
349 xexit(*av, 1);
350 }
351 arg2:
352 foundeof = *eofstr != '\0' &&
353 strncmp(argp, eofstr, p - argp) == 0;
354
355 /* Do not make empty args unless they are quoted */
356 if ((argp != p || wasquoted) && !foundeof) {
357 *p++ = '\0';
358 *xp++ = argp;
359 if (Iflag) {
360 size_t curlen;
361
362 if (inpline == NULL)
363 curlen = 0;
364 else {
365 /*
366 * If this string is not zero
367 * length, append a space for
368 * separation before the next
369 * argument.
370 */
371 if ((curlen = strlen(inpline)))
372 strcat(inpline, " ");
373 }
374 curlen++;
375 /*
376 * Allocate enough to hold what we will
377 * be holding in a second, and to append
378 * a space next time through, if we have
379 * to.
380 */
381 inpline = realloc(inpline, curlen + 2 +
382 strlen(argp));
383 if (inpline == NULL) {
384 warnx("realloc failed");
385 xexit(*av, 1);
386 }
387 if (curlen == 1)
388 strcpy(inpline, argp);
389 else
390 strcat(inpline, argp);
391 }
392 }
393
394 /*
395 * If max'd out on args or buffer, or reached EOF,
396 * run the command. If xflag and max'd out on buffer
397 * but not on args, object. Having reached the limit
398 * of input lines, as specified by -L is the same as
399 * maxing out on arguments.
400 */
401 if (xp == endxp || p > ebp || ch == EOF ||
402 (Lflag <= count && xflag) || foundeof) {
403 if (xflag && xp != endxp && p > ebp) {
404 warnx("insufficient space for arguments");
405 xexit(*av, 1);
406 }
407 if (jfound) {
408 for (avj = argv; *avj; avj++)
409 *xp++ = *avj;
410 }
411 prerun(argc, av);
412 if (ch == EOF || foundeof) {
413 waitchildren(*av, 1);
414 exit(rval);
415 }
416 p = bbp;
417 xp = bxp;
418 count = 0;
419 }
420 argp = p;
421 wasquoted = 0;
422 break;
423 case '\'':
424 if (indouble || zflag)
425 goto addch;
426 insingle = !insingle;
427 wasquoted = 1;
428 break;
429 case '"':
430 if (insingle || zflag)
431 goto addch;
432 indouble = !indouble;
433 wasquoted = 1;
434 break;
435 case '\\':
436 if (zflag)
437 goto addch;
438 /* Backslash escapes anything, is escaped by quotes. */
439 if (!insingle && !indouble && (ch = getchar()) == EOF) {
440 warnx("backslash at EOF");
441 xexit(*av, 1);
442 }
443 /* FALLTHROUGH */
444 default:
445 addch: if (p < ebp) {
446 *p++ = ch;
447 break;
448 }
449
450 /* If only one argument, not enough buffer space. */
451 if (bxp == xp) {
452 warnx("insufficient space for argument");
453 xexit(*av, 1);
454 }
455 /* Didn't hit argument limit, so if xflag object. */
456 if (xflag) {
457 warnx("insufficient space for arguments");
458 xexit(*av, 1);
459 }
460
461 if (jfound) {
462 for (avj = argv; *avj; avj++)
463 *xp++ = *avj;
464 }
465 prerun(argc, av);
466 xp = bxp;
467 cnt = ebp - argp;
468 memcpy(bbp, argp, (size_t)cnt);
469 p = (argp = bbp) + cnt;
470 *p++ = ch;
471 break;
472 }
473 }
474
475 /*
476 * Do things necessary before run()'ing, such as -I substitution,
477 * and then call run().
478 */
479 static void
prerun(int argc,char * argv[])480 prerun(int argc, char *argv[])
481 {
482 char **tmp, **tmp2, **avj;
483 int repls;
484
485 repls = Rflag;
486
487 if (argc == 0 || repls == 0) {
488 *xp = NULL;
489 run(argv);
490 return;
491 }
492
493 avj = argv;
494
495 /*
496 * Allocate memory to hold the argument list, and
497 * a NULL at the tail.
498 */
499 tmp = malloc((argc + 1) * sizeof(char *));
500 if (tmp == NULL) {
501 warnx("malloc failed");
502 xexit(*argv, 1);
503 }
504 tmp2 = tmp;
505
506 /*
507 * Save the first argument and iterate over it, we
508 * cannot do strnsubst() to it.
509 */
510 if ((*tmp++ = strdup(*avj++)) == NULL) {
511 warnx("strdup failed");
512 xexit(*argv, 1);
513 }
514
515 /*
516 * For each argument to utility, if we have not used up
517 * the number of replacements we are allowed to do, and
518 * if the argument contains at least one occurrence of
519 * replstr, call strnsubst(), else just save the string.
520 * Iterations over elements of avj and tmp are done
521 * where appropriate.
522 */
523 while (--argc) {
524 *tmp = *avj++;
525 if (repls && strstr(*tmp, replstr) != NULL) {
526 if (strnsubst(tmp++, replstr, inpline, (size_t)Sflag)) {
527 warnx("comamnd line cannot be assembled, too long");
528 xexit(*argv, 1);
529 }
530 if (repls > 0)
531 repls--;
532 } else {
533 if ((*tmp = strdup(*tmp)) == NULL) {
534 warnx("strdup failed");
535 xexit(*argv, 1);
536 }
537 tmp++;
538 }
539 }
540
541 /*
542 * Run it.
543 */
544 *tmp = NULL;
545 run(tmp2);
546
547 /*
548 * Walk from the tail to the head, free along the way.
549 */
550 for (; tmp2 != tmp; tmp--)
551 free(*tmp);
552 /*
553 * Now free the list itself.
554 */
555 free(tmp2);
556
557 /*
558 * Free the input line buffer, if we have one.
559 */
560 if (inpline != NULL) {
561 free(inpline);
562 inpline = NULL;
563 }
564 }
565
566 static void
run(char ** argv)567 run(char **argv)
568 {
569 pid_t pid;
570 int fd;
571 char **avec;
572
573 /*
574 * If the user wants to be notified of each command before it is
575 * executed, notify them. If they want the notification to be
576 * followed by a prompt, then prompt them.
577 */
578 if (tflag || pflag) {
579 (void)fprintf(stderr, "%s", *argv);
580 for (avec = argv + 1; *avec != NULL; ++avec)
581 (void)fprintf(stderr, " %s", *avec);
582 /*
583 * If the user has asked to be prompted, do so.
584 */
585 #ifndef BOOTSTRAPPING
586 if (pflag)
587 /*
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.
592 */
593 switch (prompt()) {
594 case 0:
595 return;
596 case 1:
597 goto exec;
598 case 2:
599 break;
600 }
601 #endif
602 (void)fprintf(stderr, "\n");
603 (void)fflush(stderr);
604 }
605 #ifndef BOOTSTRAPPING
606 exec:
607 #endif
608 childerr = 0;
609 switch (pid = vfork()) {
610 case -1:
611 warn("vfork");
612 xexit(*argv, 1);
613 break;
614 case 0:
615 if (oflag) {
616 if ((fd = open(_PATH_TTY, O_RDONLY)) == -1)
617 err(1, "can't open /dev/tty");
618 } else {
619 fd = open(_PATH_DEVNULL, O_RDONLY);
620 }
621 if (fd > STDIN_FILENO) {
622 if (dup2(fd, STDIN_FILENO) != 0)
623 err(1, "can't dup2 to stdin");
624 close(fd);
625 }
626 execvp(argv[0], argv);
627 childerr = errno;
628 _exit(1);
629 }
630 pids_add(pid);
631 waitchildren(*argv, 0);
632 }
633
634 /*
635 * Wait for a tracked child to exit and return its pid and exit status.
636 *
637 * Ignores (discards) all untracked child processes.
638 * Returns -1 and sets errno to ECHILD if no tracked children exist.
639 * If block is set, waits indefinitely for a child process to exit.
640 * If block is not set and no children have exited, returns 0 immediately.
641 */
642 static pid_t
xwait(int block,int * status)643 xwait(int block, int *status) {
644 pid_t pid;
645
646 if (pids_empty()) {
647 errno = ECHILD;
648 return (-1);
649 }
650
651 while ((pid = waitpid(-1, status, block ? 0 : WNOHANG)) > 0)
652 if (pids_remove(pid))
653 break;
654
655 return (pid);
656 }
657
658 static void
xexit(const char * name,const int exit_code)659 xexit(const char *name, const int exit_code) {
660 waitchildren(name, 1);
661 exit(exit_code);
662 }
663
664 static void
waitchildren(const char * name,int waitall)665 waitchildren(const char *name, int waitall)
666 {
667 pid_t pid;
668 int status;
669 int cause_exit = 0;
670
671 while ((pid = xwait(waitall || pids_full(), &status)) > 0) {
672 /*
673 * If we couldn't invoke the utility or if utility exited
674 * because of a signal or with a value of 255, warn (per
675 * POSIX), and then wait until all other children have
676 * exited before exiting 1-125. POSIX requires us to stop
677 * reading if child exits because of a signal or with 255,
678 * but it does not require us to exit immediately; waiting
679 * is preferable to orphaning.
680 */
681 if (childerr != 0 && cause_exit == 0) {
682 errno = childerr;
683 waitall = 1;
684 cause_exit = errno == ENOENT ? 127 : 126;
685 warn("%s", name);
686 } else if (WIFSIGNALED(status)) {
687 waitall = cause_exit = 1;
688 if (WTERMSIG(status) != SIGPIPE) {
689 if (WTERMSIG(status) < NSIG)
690 warnx("%s terminated by SIG%s", name,
691 sys_signame[WTERMSIG(status)]);
692 else
693 warnx("%s terminated by signal %d",
694 name, WTERMSIG(status));
695 }
696 } else if (WEXITSTATUS(status) == 255) {
697 waitall = cause_exit = 1;
698 warnx("%s: exited with status 255; aborting", name);
699 } else if (WEXITSTATUS(status))
700 rval = 1;
701 }
702
703 if (cause_exit)
704 exit(cause_exit);
705 if (pid == -1 && errno != ECHILD)
706 err(1, "waitpid");
707 }
708
709 #define NOPID (0)
710
711 static void
pids_init(void)712 pids_init(void)
713 {
714 int i;
715
716 if ((childpids = malloc(maxprocs * sizeof(*childpids))) == NULL)
717 errx(1, "malloc failed");
718
719 for (i = 0; i < maxprocs; i++)
720 clearslot(i);
721 }
722
723 static int
pids_empty(void)724 pids_empty(void)
725 {
726
727 return (curprocs == 0);
728 }
729
730 static int
pids_full(void)731 pids_full(void)
732 {
733
734 return (curprocs >= maxprocs);
735 }
736
737 static void
pids_add(pid_t pid)738 pids_add(pid_t pid)
739 {
740 int slot;
741
742 slot = findfreeslot();
743 childpids[slot] = pid;
744 curprocs++;
745 }
746
747 static int
pids_remove(pid_t pid)748 pids_remove(pid_t pid)
749 {
750 int slot;
751
752 if ((slot = findslot(pid)) < 0)
753 return (0);
754
755 clearslot(slot);
756 curprocs--;
757 return (1);
758 }
759
760 static int
findfreeslot(void)761 findfreeslot(void)
762 {
763 int slot;
764
765 if ((slot = findslot(NOPID)) < 0)
766 errx(1, "internal error: no free pid slot");
767 return (slot);
768 }
769
770 static int
findslot(pid_t pid)771 findslot(pid_t pid)
772 {
773 int slot;
774
775 for (slot = 0; slot < maxprocs; slot++)
776 if (childpids[slot] == pid)
777 return (slot);
778 return (-1);
779 }
780
781 static void
clearslot(int slot)782 clearslot(int slot)
783 {
784
785 childpids[slot] = NOPID;
786 }
787
788 /*
789 * Prompt the user about running a command.
790 */
791 #ifndef BOOTSTRAPPING
792 static int
prompt(void)793 prompt(void)
794 {
795 regex_t cre;
796 size_t rsize;
797 int match;
798 char *response;
799 FILE *ttyfp;
800
801 if ((ttyfp = fopen(_PATH_TTY, "r")) == NULL)
802 return (2); /* Indicate that the TTY failed to open. */
803 (void)fprintf(stderr, "?...");
804 (void)fflush(stderr);
805 if ((response = fgetln(ttyfp, &rsize)) == NULL ||
806 regcomp(&cre, nl_langinfo(YESEXPR), REG_EXTENDED) != 0) {
807 (void)fclose(ttyfp);
808 return (0);
809 }
810 response[rsize - 1] = '\0';
811 match = regexec(&cre, response, 0, NULL, 0);
812 (void)fclose(ttyfp);
813 regfree(&cre);
814 return (match == 0);
815 }
816 #endif
817
818 static void
usage(void)819 usage(void)
820 {
821
822 fprintf(stderr,
823 "usage: xargs [-0opt] [-E eofstr] [-I replstr [-R replacements] [-S replsize]]\n"
824 " [-J replstr] [-L number] [-n number [-x]] [-P maxprocs]\n"
825 " [-s size] [utility [argument ...]]\n");
826 exit(1);
827 }
828