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
37 #if 0
38 #ifndef lint
39 static const char copyright[] =
40 "@(#) Copyright (c) 1990, 1993\n\
41 The Regents of the University of California. All rights reserved.\n";
42 #endif /* not lint */
43
44 #ifndef lint
45 static char sccsid[] = "@(#)xargs.c 8.1 (Berkeley) 6/6/93";
46 #endif /* not lint */
47 #endif
48 #include <sys/cdefs.h>
49 __FBSDID("$FreeBSD$");
50
51 #include <sys/types.h>
52 #include <sys/wait.h>
53 #include <sys/time.h>
54 #include <sys/limits.h>
55 #include <sys/resource.h>
56 #include <err.h>
57 #include <errno.h>
58 #include <fcntl.h>
59 #include <getopt.h>
60 #include <langinfo.h>
61 #include <locale.h>
62 #include <paths.h>
63 #include <regex.h>
64 #include <stdio.h>
65 #include <stdlib.h>
66 #include <string.h>
67 #include <unistd.h>
68
69 #include "pathnames.h"
70
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);
88
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;
97
98 static volatile int childerr;
99
100 extern char **environ;
101
102 static const char *optstr = "+0E:I:J:L:n:oP:pR:S:s:rtx";
103
104 static const struct option long_options[] =
105 {
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'},
114
115 {NULL, no_argument, NULL, 0},
116 };
117
118 int
main(int argc,char * argv[])119 main(int argc, char *argv[])
120 {
121 long arg_max;
122 int ch, Jflag, nargs, nflag, nline;
123 size_t linelen;
124 struct rlimit rl;
125 char *endptr;
126 const char *errstr;
127
128 inpline = replstr = NULL;
129 ep = environ;
130 eofstr = "";
131 Jflag = nflag = 0;
132
133 (void)setlocale(LC_ALL, "");
134
135 /*
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:
140 *
141 * (ARG_MAX - 4K - LENGTH(utility + arguments)) / 2.
142 *
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.
147 */
148 nargs = 5000;
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);
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 pflag = 1;
198 break;
199 case 'R':
200 Rflag = strtol(optarg, &endptr, 10);
201 if (*endptr != '\0')
202 errx(1, "replacements must be a number");
203 break;
204 case 'r':
205 /* GNU compatibility */
206 break;
207 case 'S':
208 Sflag = strtoul(optarg, &endptr, 10);
209 if (*endptr != '\0')
210 errx(1, "replsize must be a number");
211 break;
212 case 's':
213 nline = strtonum(optarg, 0, INT_MAX, &errstr);
214 if (errstr)
215 errx(1, "-s %s: %s", optarg, errstr);
216 break;
217 case 't':
218 tflag = 1;
219 break;
220 case 'x':
221 xflag = 1;
222 break;
223 case '0':
224 zflag = 1;
225 break;
226 case '?':
227 default:
228 usage();
229 }
230 argc -= optind;
231 argv += optind;
232
233 if (!Iflag && Rflag)
234 usage();
235 if (!Iflag && Sflag)
236 usage();
237 if (Iflag && !Rflag)
238 Rflag = 5;
239 if (Iflag && !Sflag)
240 Sflag = 255;
241 if (xflag && !nflag)
242 usage();
243 if (Iflag || Lflag)
244 xflag = 1;
245 if (replstr != NULL && *replstr == '\0')
246 errx(1, "replstr may not be empty");
247
248 pids_init();
249
250 /*
251 * Allocate pointers for the utility name, the utility arguments,
252 * the maximum arguments to be read from stdin and the trailing
253 * NULL.
254 */
255 linelen = 1 + argc + nargs + 1;
256 if ((av = bxp = malloc(linelen * sizeof(char *))) == NULL)
257 errx(1, "malloc failed");
258
259 /*
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
262 * arguments.
263 */
264 if (*argv == NULL)
265 cnt = strlen(*bxp++ = echo);
266 else {
267 do {
268 if (Jflag && strcmp(*argv, replstr) == 0) {
269 char **avj;
270 jfound = 1;
271 argv++;
272 for (avj = argv; *avj; avj++)
273 cnt += strlen(*avj) + 1;
274 break;
275 }
276 cnt += strlen(*bxp++ = *argv) + 1;
277 } while (*++argv != NULL);
278 }
279
280 /*
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.
284 */
285 endxp = (xp = bxp) + nargs;
286
287 /*
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
293 * slot.
294 */
295 nline -= cnt;
296 if (nline <= 0)
297 errx(1, "insufficient space for command");
298
299 if ((bbp = malloc((size_t)(nline + 1))) == NULL)
300 errx(1, "malloc failed");
301 ebp = (argp = p = bbp) + nline - 1;
302 for (;;)
303 parse_input(argc, argv);
304 }
305
306 static void
parse_input(int argc,char * argv[])307 parse_input(int argc, char *argv[])
308 {
309 int ch, foundeof;
310 char **avj;
311
312 foundeof = 0;
313
314 switch (ch = getchar()) {
315 case EOF:
316 /* No arguments since last exec. */
317 if (p == bbp)
318 xexit(*av, rval);
319 goto arg1;
320 case ' ':
321 case '\t':
322 /* Quotes escape tabs and spaces. */
323 if (insingle || indouble || zflag)
324 goto addch;
325 goto arg2;
326 case '\0':
327 if (zflag) {
328 /*
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.
332 */
333 count++;
334 goto arg2;
335 }
336 goto addch;
337 case '\n':
338 if (zflag)
339 goto addch;
340 count++; /* Indicate end-of-line (used by -L) */
341
342 /* Quotes do not escape newlines. */
343 arg1: if (insingle || indouble) {
344 warnx("unterminated quote");
345 xexit(*av, 1);
346 }
347 arg2:
348 foundeof = *eofstr != '\0' &&
349 strncmp(argp, eofstr, p - argp) == 0;
350
351 /* Do not make empty args unless they are quoted */
352 if ((argp != p || wasquoted) && !foundeof) {
353 *p++ = '\0';
354 *xp++ = argp;
355 if (Iflag) {
356 size_t curlen;
357
358 if (inpline == NULL)
359 curlen = 0;
360 else {
361 /*
362 * If this string is not zero
363 * length, append a space for
364 * separation before the next
365 * argument.
366 */
367 if ((curlen = strlen(inpline)))
368 strcat(inpline, " ");
369 }
370 curlen++;
371 /*
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
375 * to.
376 */
377 inpline = realloc(inpline, curlen + 2 +
378 strlen(argp));
379 if (inpline == NULL) {
380 warnx("realloc failed");
381 xexit(*av, 1);
382 }
383 if (curlen == 1)
384 strcpy(inpline, argp);
385 else
386 strcat(inpline, argp);
387 }
388 }
389
390 /*
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.
396 */
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");
401 xexit(*av, 1);
402 }
403 if (jfound) {
404 for (avj = argv; *avj; avj++)
405 *xp++ = *avj;
406 }
407 prerun(argc, av);
408 if (ch == EOF || foundeof)
409 xexit(*av, rval);
410 p = bbp;
411 xp = bxp;
412 count = 0;
413 }
414 argp = p;
415 wasquoted = 0;
416 break;
417 case '\'':
418 if (indouble || zflag)
419 goto addch;
420 insingle = !insingle;
421 wasquoted = 1;
422 break;
423 case '"':
424 if (insingle || zflag)
425 goto addch;
426 indouble = !indouble;
427 wasquoted = 1;
428 break;
429 case '\\':
430 if (zflag)
431 goto addch;
432 /* Backslash escapes anything, is escaped by quotes. */
433 if (!insingle && !indouble && (ch = getchar()) == EOF) {
434 warnx("backslash at EOF");
435 xexit(*av, 1);
436 }
437 /* FALLTHROUGH */
438 default:
439 addch: if (p < ebp) {
440 *p++ = ch;
441 break;
442 }
443
444 /* If only one argument, not enough buffer space. */
445 if (bxp == xp) {
446 warnx("insufficient space for argument");
447 xexit(*av, 1);
448 }
449 /* Didn't hit argument limit, so if xflag object. */
450 if (xflag) {
451 warnx("insufficient space for arguments");
452 xexit(*av, 1);
453 }
454
455 if (jfound) {
456 for (avj = argv; *avj; avj++)
457 *xp++ = *avj;
458 }
459 prerun(argc, av);
460 xp = bxp;
461 cnt = ebp - argp;
462 memcpy(bbp, argp, (size_t)cnt);
463 p = (argp = bbp) + cnt;
464 *p++ = ch;
465 break;
466 }
467 }
468
469 /*
470 * Do things necessary before run()'ing, such as -I substitution,
471 * and then call run().
472 */
473 static void
prerun(int argc,char * argv[])474 prerun(int argc, char *argv[])
475 {
476 char **tmp, **tmp2, **avj;
477 int repls;
478
479 repls = Rflag;
480
481 if (argc == 0 || repls == 0) {
482 *xp = NULL;
483 run(argv);
484 return;
485 }
486
487 avj = argv;
488
489 /*
490 * Allocate memory to hold the argument list, and
491 * a NULL at the tail.
492 */
493 tmp = malloc((argc + 1) * sizeof(char *));
494 if (tmp == NULL) {
495 warnx("malloc failed");
496 xexit(*argv, 1);
497 }
498 tmp2 = tmp;
499
500 /*
501 * Save the first argument and iterate over it, we
502 * cannot do strnsubst() to it.
503 */
504 if ((*tmp++ = strdup(*avj++)) == NULL) {
505 warnx("strdup failed");
506 xexit(*argv, 1);
507 }
508
509 /*
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
515 * where appropriate.
516 */
517 while (--argc) {
518 *tmp = *avj++;
519 if (repls && strstr(*tmp, replstr) != NULL) {
520 strnsubst(tmp++, replstr, inpline, (size_t)Sflag);
521 if (repls > 0)
522 repls--;
523 } else {
524 if ((*tmp = strdup(*tmp)) == NULL) {
525 warnx("strdup failed");
526 xexit(*argv, 1);
527 }
528 tmp++;
529 }
530 }
531
532 /*
533 * Run it.
534 */
535 *tmp = NULL;
536 run(tmp2);
537
538 /*
539 * Walk from the tail to the head, free along the way.
540 */
541 for (; tmp2 != tmp; tmp--)
542 free(*tmp);
543 /*
544 * Now free the list itself.
545 */
546 free(tmp2);
547
548 /*
549 * Free the input line buffer, if we have one.
550 */
551 if (inpline != NULL) {
552 free(inpline);
553 inpline = NULL;
554 }
555 }
556
557 static void
run(char ** argv)558 run(char **argv)
559 {
560 pid_t pid;
561 int fd;
562 char **avec;
563
564 /*
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.
568 */
569 if (tflag || pflag) {
570 (void)fprintf(stderr, "%s", *argv);
571 for (avec = argv + 1; *avec != NULL; ++avec)
572 (void)fprintf(stderr, " %s", *avec);
573 /*
574 * If the user has asked to be prompted, do so.
575 */
576 if (pflag)
577 /*
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.
582 */
583 switch (prompt()) {
584 case 0:
585 return;
586 case 1:
587 goto exec;
588 case 2:
589 break;
590 }
591 (void)fprintf(stderr, "\n");
592 (void)fflush(stderr);
593 }
594 exec:
595 childerr = 0;
596 switch (pid = vfork()) {
597 case -1:
598 warn("vfork");
599 xexit(*argv, 1);
600 case 0:
601 if (oflag) {
602 if ((fd = open(_PATH_TTY, O_RDONLY)) == -1)
603 err(1, "can't open /dev/tty");
604 } else {
605 fd = open(_PATH_DEVNULL, O_RDONLY);
606 }
607 if (fd > STDIN_FILENO) {
608 if (dup2(fd, STDIN_FILENO) != 0)
609 err(1, "can't dup2 to stdin");
610 close(fd);
611 }
612 execvp(argv[0], argv);
613 childerr = errno;
614 _exit(1);
615 }
616 pids_add(pid);
617 waitchildren(*argv, 0);
618 }
619
620 /*
621 * Wait for a tracked child to exit and return its pid and exit status.
622 *
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.
627 */
628 static pid_t
xwait(int block,int * status)629 xwait(int block, int *status) {
630 pid_t pid;
631
632 if (pids_empty()) {
633 errno = ECHILD;
634 return (-1);
635 }
636
637 while ((pid = waitpid(-1, status, block ? 0 : WNOHANG)) > 0)
638 if (pids_remove(pid))
639 break;
640
641 return (pid);
642 }
643
644 static void
xexit(const char * name,const int exit_code)645 xexit(const char *name, const int exit_code) {
646 waitchildren(name, 1);
647 exit(exit_code);
648 }
649
650 static void
waitchildren(const char * name,int waitall)651 waitchildren(const char *name, int waitall)
652 {
653 pid_t pid;
654 int status;
655 int cause_exit = 0;
656
657 while ((pid = xwait(waitall || pids_full(), &status)) > 0) {
658 /*
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.
666 */
667 if (childerr != 0 && cause_exit == 0) {
668 errno = childerr;
669 waitall = 1;
670 cause_exit = errno == ENOENT ? 127 : 126;
671 warn("%s", name);
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))
680 rval = 1;
681 }
682
683 if (cause_exit)
684 exit(cause_exit);
685 if (pid == -1 && errno != ECHILD)
686 err(1, "waitpid");
687 }
688
689 #define NOPID (0)
690
691 static void
pids_init(void)692 pids_init(void)
693 {
694 int i;
695
696 if ((childpids = malloc(maxprocs * sizeof(*childpids))) == NULL)
697 errx(1, "malloc failed");
698
699 for (i = 0; i < maxprocs; i++)
700 clearslot(i);
701 }
702
703 static int
pids_empty(void)704 pids_empty(void)
705 {
706
707 return (curprocs == 0);
708 }
709
710 static int
pids_full(void)711 pids_full(void)
712 {
713
714 return (curprocs >= maxprocs);
715 }
716
717 static void
pids_add(pid_t pid)718 pids_add(pid_t pid)
719 {
720 int slot;
721
722 slot = findfreeslot();
723 childpids[slot] = pid;
724 curprocs++;
725 }
726
727 static int
pids_remove(pid_t pid)728 pids_remove(pid_t pid)
729 {
730 int slot;
731
732 if ((slot = findslot(pid)) < 0)
733 return (0);
734
735 clearslot(slot);
736 curprocs--;
737 return (1);
738 }
739
740 static int
findfreeslot(void)741 findfreeslot(void)
742 {
743 int slot;
744
745 if ((slot = findslot(NOPID)) < 0)
746 errx(1, "internal error: no free pid slot");
747 return (slot);
748 }
749
750 static int
findslot(pid_t pid)751 findslot(pid_t pid)
752 {
753 int slot;
754
755 for (slot = 0; slot < maxprocs; slot++)
756 if (childpids[slot] == pid)
757 return (slot);
758 return (-1);
759 }
760
761 static void
clearslot(int slot)762 clearslot(int slot)
763 {
764
765 childpids[slot] = NOPID;
766 }
767
768 /*
769 * Prompt the user about running a command.
770 */
771 static int
prompt(void)772 prompt(void)
773 {
774 regex_t cre;
775 size_t rsize;
776 int match;
777 char *response;
778 FILE *ttyfp;
779
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) {
786 (void)fclose(ttyfp);
787 return (0);
788 }
789 response[rsize - 1] = '\0';
790 match = regexec(&cre, response, 0, NULL, 0);
791 (void)fclose(ttyfp);
792 regfree(&cre);
793 return (match == 0);
794 }
795
796 static void
usage(void)797 usage(void)
798 {
799
800 fprintf(stderr,
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");
804 exit(1);
805 }
806