1 /*-
2 * Copyright (c) 1990, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * John B. Roll Jr.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
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 * 4. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 * $xMach: xargs.c,v 1.6 2002/02/23 05:27:47 tim Exp $
33 */
34
35 #if 0
36 #ifndef lint
37 static const char copyright[] =
38 "@(#) Copyright (c) 1990, 1993\n\
39 The Regents of the University of California. All rights reserved.\n";
40 #endif /* not lint */
41
42 #ifndef lint
43 static char sccsid[] = "@(#)xargs.c 8.1 (Berkeley) 6/6/93";
44 #endif /* not lint */
45 #endif
46 #include <sys/cdefs.h>
47 __FBSDID("$FreeBSD: stable/10/usr.bin/xargs/xargs.c 293726 2016-01-12 05:51:12Z allanjude $");
48
49 #include <sys/types.h>
50 #include <sys/wait.h>
51 #include <sys/time.h>
52 #include <sys/limits.h>
53 #include <sys/resource.h>
54 #include <err.h>
55 #include <errno.h>
56 #include <fcntl.h>
57 #include <langinfo.h>
58 #include <locale.h>
59 #include <paths.h>
60 #include <regex.h>
61 #include <stdio.h>
62 #include <stdlib.h>
63 #include <string.h>
64 #include <unistd.h>
65
66 #include "pathnames.h"
67
68 static void parse_input(int, char *[]);
69 static void prerun(int, char *[]);
70 static int prompt(void);
71 static void run(char **);
72 static void usage(void);
73 void strnsubst(char **, const char *, const char *, size_t);
74 static pid_t xwait(int block, int *status);
75 static void xexit(const char *, const int);
76 static void waitchildren(const char *, int);
77 static void pids_init(void);
78 static int pids_empty(void);
79 static int pids_full(void);
80 static void pids_add(pid_t pid);
81 static int pids_remove(pid_t pid);
82 static int findslot(pid_t pid);
83 static int findfreeslot(void);
84 static void clearslot(int slot);
85
86 static char echo[] = _PATH_ECHO;
87 static char **av, **bxp, **ep, **endxp, **xp;
88 static char *argp, *bbp, *ebp, *inpline, *p, *replstr;
89 static const char *eofstr;
90 static int count, insingle, indouble, oflag, pflag, tflag, Rflag, rval, zflag;
91 static int cnt, Iflag, jfound, Lflag, Sflag, wasquoted, xflag;
92 static int curprocs, maxprocs;
93 static pid_t *childpids;
94
95 static volatile int childerr;
96
97 extern char **environ;
98
99 int
main(int argc,char * argv[])100 main(int argc, char *argv[])
101 {
102 long arg_max;
103 int ch, Jflag, nargs, nflag, nline;
104 size_t linelen;
105 struct rlimit rl;
106 char *endptr;
107 const char *errstr;
108
109 inpline = replstr = NULL;
110 ep = environ;
111 eofstr = "";
112 Jflag = nflag = 0;
113
114 (void)setlocale(LC_ALL, "");
115
116 /*
117 * POSIX.2 limits the exec line length to ARG_MAX - 2K. Running that
118 * caused some E2BIG errors, so it was changed to ARG_MAX - 4K. Given
119 * that the smallest argument is 2 bytes in length, this means that
120 * the number of arguments is limited to:
121 *
122 * (ARG_MAX - 4K - LENGTH(utility + arguments)) / 2.
123 *
124 * We arbitrarily limit the number of arguments to 5000. This is
125 * allowed by POSIX.2 as long as the resulting minimum exec line is
126 * at least LINE_MAX. Realloc'ing as necessary is possible, but
127 * probably not worthwhile.
128 */
129 nargs = 5000;
130 if ((arg_max = sysconf(_SC_ARG_MAX)) == -1)
131 errx(1, "sysconf(_SC_ARG_MAX) failed");
132 nline = arg_max - 4 * 1024;
133 while (*ep != NULL) {
134 /* 1 byte for each '\0' */
135 nline -= strlen(*ep++) + 1 + sizeof(*ep);
136 }
137 maxprocs = 1;
138 while ((ch = getopt(argc, argv, "0E:I:J:L:n:oP:pR:S:s:rtx")) != -1)
139 switch (ch) {
140 case 'E':
141 eofstr = optarg;
142 break;
143 case 'I':
144 Jflag = 0;
145 Iflag = 1;
146 Lflag = 1;
147 replstr = optarg;
148 break;
149 case 'J':
150 Iflag = 0;
151 Jflag = 1;
152 replstr = optarg;
153 break;
154 case 'L':
155 Lflag = strtonum(optarg, 0, INT_MAX, &errstr);
156 if (errstr)
157 errx(1, "-L %s: %s", optarg, errstr);
158 break;
159 case 'n':
160 nflag = 1;
161 nargs = strtonum(optarg, 1, INT_MAX, &errstr);
162 if (errstr)
163 errx(1, "-n %s: %s", optarg, errstr);
164 break;
165 case 'o':
166 oflag = 1;
167 break;
168 case 'P':
169 maxprocs = strtonum(optarg, 0, INT_MAX, &errstr);
170 if (errstr)
171 errx(1, "-P %s: %s", optarg, errstr);
172 if (getrlimit(RLIMIT_NPROC, &rl) != 0)
173 errx(1, "getrlimit failed");
174 if (maxprocs == 0 || maxprocs > rl.rlim_cur)
175 maxprocs = rl.rlim_cur;
176 break;
177 case 'p':
178 pflag = 1;
179 break;
180 case 'R':
181 Rflag = strtol(optarg, &endptr, 10);
182 if (*endptr != '\0')
183 errx(1, "replacements must be a number");
184 break;
185 case 'r':
186 /* GNU compatibility */
187 break;
188 case 'S':
189 Sflag = strtoul(optarg, &endptr, 10);
190 if (*endptr != '\0')
191 errx(1, "replsize must be a number");
192 break;
193 case 's':
194 nline = strtonum(optarg, 0, INT_MAX, &errstr);
195 if (errstr)
196 errx(1, "-s %s: %s", optarg, errstr);
197 break;
198 case 't':
199 tflag = 1;
200 break;
201 case 'x':
202 xflag = 1;
203 break;
204 case '0':
205 zflag = 1;
206 break;
207 case '?':
208 default:
209 usage();
210 }
211 argc -= optind;
212 argv += optind;
213
214 if (!Iflag && Rflag)
215 usage();
216 if (!Iflag && Sflag)
217 usage();
218 if (Iflag && !Rflag)
219 Rflag = 5;
220 if (Iflag && !Sflag)
221 Sflag = 255;
222 if (xflag && !nflag)
223 usage();
224 if (Iflag || Lflag)
225 xflag = 1;
226 if (replstr != NULL && *replstr == '\0')
227 errx(1, "replstr may not be empty");
228
229 pids_init();
230
231 /*
232 * Allocate pointers for the utility name, the utility arguments,
233 * the maximum arguments to be read from stdin and the trailing
234 * NULL.
235 */
236 linelen = 1 + argc + nargs + 1;
237 if ((av = bxp = malloc(linelen * sizeof(char **))) == NULL)
238 errx(1, "malloc failed");
239
240 /*
241 * Use the user's name for the utility as argv[0], just like the
242 * shell. Echo is the default. Set up pointers for the user's
243 * arguments.
244 */
245 if (*argv == NULL)
246 cnt = strlen(*bxp++ = echo);
247 else {
248 do {
249 if (Jflag && strcmp(*argv, replstr) == 0) {
250 char **avj;
251 jfound = 1;
252 argv++;
253 for (avj = argv; *avj; avj++)
254 cnt += strlen(*avj) + 1;
255 break;
256 }
257 cnt += strlen(*bxp++ = *argv) + 1;
258 } while (*++argv != NULL);
259 }
260
261 /*
262 * Set up begin/end/traversing pointers into the array. The -n
263 * count doesn't include the trailing NULL pointer, so the malloc
264 * added in an extra slot.
265 */
266 endxp = (xp = bxp) + nargs;
267
268 /*
269 * Allocate buffer space for the arguments read from stdin and the
270 * trailing NULL. Buffer space is defined as the default or specified
271 * space, minus the length of the utility name and arguments. Set up
272 * begin/end/traversing pointers into the array. The -s count does
273 * include the trailing NULL, so the malloc didn't add in an extra
274 * slot.
275 */
276 nline -= cnt;
277 if (nline <= 0)
278 errx(1, "insufficient space for command");
279
280 if ((bbp = malloc((size_t)(nline + 1))) == NULL)
281 errx(1, "malloc failed");
282 ebp = (argp = p = bbp) + nline - 1;
283 for (;;)
284 parse_input(argc, argv);
285 }
286
287 static void
parse_input(int argc,char * argv[])288 parse_input(int argc, char *argv[])
289 {
290 int ch, foundeof;
291 char **avj;
292
293 foundeof = 0;
294
295 switch (ch = getchar()) {
296 case EOF:
297 /* No arguments since last exec. */
298 if (p == bbp)
299 xexit(*av, rval);
300 goto arg1;
301 case ' ':
302 case '\t':
303 /* Quotes escape tabs and spaces. */
304 if (insingle || indouble || zflag)
305 goto addch;
306 goto arg2;
307 case '\0':
308 if (zflag) {
309 /*
310 * Increment 'count', so that nulls will be treated
311 * as end-of-line, as well as end-of-argument. This
312 * is needed so -0 works properly with -I and -L.
313 */
314 count++;
315 goto arg2;
316 }
317 goto addch;
318 case '\n':
319 if (zflag)
320 goto addch;
321 count++; /* Indicate end-of-line (used by -L) */
322
323 /* Quotes do not escape newlines. */
324 arg1: if (insingle || indouble) {
325 warnx("unterminated quote");
326 xexit(*av, 1);
327 }
328 arg2:
329 foundeof = *eofstr != '\0' &&
330 strncmp(argp, eofstr, p - argp) == 0;
331
332 /* Do not make empty args unless they are quoted */
333 if ((argp != p || wasquoted) && !foundeof) {
334 *p++ = '\0';
335 *xp++ = argp;
336 if (Iflag) {
337 size_t curlen;
338
339 if (inpline == NULL)
340 curlen = 0;
341 else {
342 /*
343 * If this string is not zero
344 * length, append a space for
345 * separation before the next
346 * argument.
347 */
348 if ((curlen = strlen(inpline)))
349 strcat(inpline, " ");
350 }
351 curlen++;
352 /*
353 * Allocate enough to hold what we will
354 * be holding in a second, and to append
355 * a space next time through, if we have
356 * to.
357 */
358 inpline = realloc(inpline, curlen + 2 +
359 strlen(argp));
360 if (inpline == NULL) {
361 warnx("realloc failed");
362 xexit(*av, 1);
363 }
364 if (curlen == 1)
365 strcpy(inpline, argp);
366 else
367 strcat(inpline, argp);
368 }
369 }
370
371 /*
372 * If max'd out on args or buffer, or reached EOF,
373 * run the command. If xflag and max'd out on buffer
374 * but not on args, object. Having reached the limit
375 * of input lines, as specified by -L is the same as
376 * maxing out on arguments.
377 */
378 if (xp == endxp || p > ebp || ch == EOF ||
379 (Lflag <= count && xflag) || foundeof) {
380 if (xflag && xp != endxp && p > ebp) {
381 warnx("insufficient space for arguments");
382 xexit(*av, 1);
383 }
384 if (jfound) {
385 for (avj = argv; *avj; avj++)
386 *xp++ = *avj;
387 }
388 prerun(argc, av);
389 if (ch == EOF || foundeof)
390 xexit(*av, rval);
391 p = bbp;
392 xp = bxp;
393 count = 0;
394 }
395 argp = p;
396 wasquoted = 0;
397 break;
398 case '\'':
399 if (indouble || zflag)
400 goto addch;
401 insingle = !insingle;
402 wasquoted = 1;
403 break;
404 case '"':
405 if (insingle || zflag)
406 goto addch;
407 indouble = !indouble;
408 wasquoted = 1;
409 break;
410 case '\\':
411 if (zflag)
412 goto addch;
413 /* Backslash escapes anything, is escaped by quotes. */
414 if (!insingle && !indouble && (ch = getchar()) == EOF) {
415 warnx("backslash at EOF");
416 xexit(*av, 1);
417 }
418 /* FALLTHROUGH */
419 default:
420 addch: if (p < ebp) {
421 *p++ = ch;
422 break;
423 }
424
425 /* If only one argument, not enough buffer space. */
426 if (bxp == xp) {
427 warnx("insufficient space for argument");
428 xexit(*av, 1);
429 }
430 /* Didn't hit argument limit, so if xflag object. */
431 if (xflag) {
432 warnx("insufficient space for arguments");
433 xexit(*av, 1);
434 }
435
436 if (jfound) {
437 for (avj = argv; *avj; avj++)
438 *xp++ = *avj;
439 }
440 prerun(argc, av);
441 xp = bxp;
442 cnt = ebp - argp;
443 memcpy(bbp, argp, (size_t)cnt);
444 p = (argp = bbp) + cnt;
445 *p++ = ch;
446 break;
447 }
448 }
449
450 /*
451 * Do things necessary before run()'ing, such as -I substitution,
452 * and then call run().
453 */
454 static void
prerun(int argc,char * argv[])455 prerun(int argc, char *argv[])
456 {
457 char **tmp, **tmp2, **avj;
458 int repls;
459
460 repls = Rflag;
461
462 if (argc == 0 || repls == 0) {
463 *xp = NULL;
464 run(argv);
465 return;
466 }
467
468 avj = argv;
469
470 /*
471 * Allocate memory to hold the argument list, and
472 * a NULL at the tail.
473 */
474 tmp = malloc((argc + 1) * sizeof(char**));
475 if (tmp == NULL) {
476 warnx("malloc failed");
477 xexit(*argv, 1);
478 }
479 tmp2 = tmp;
480
481 /*
482 * Save the first argument and iterate over it, we
483 * cannot do strnsubst() to it.
484 */
485 if ((*tmp++ = strdup(*avj++)) == NULL) {
486 warnx("strdup failed");
487 xexit(*argv, 1);
488 }
489
490 /*
491 * For each argument to utility, if we have not used up
492 * the number of replacements we are allowed to do, and
493 * if the argument contains at least one occurrence of
494 * replstr, call strnsubst(), else just save the string.
495 * Iterations over elements of avj and tmp are done
496 * where appropriate.
497 */
498 while (--argc) {
499 *tmp = *avj++;
500 if (repls && strstr(*tmp, replstr) != NULL) {
501 strnsubst(tmp++, replstr, inpline, (size_t)Sflag);
502 if (repls > 0)
503 repls--;
504 } else {
505 if ((*tmp = strdup(*tmp)) == NULL) {
506 warnx("strdup failed");
507 xexit(*argv, 1);
508 }
509 tmp++;
510 }
511 }
512
513 /*
514 * Run it.
515 */
516 *tmp = NULL;
517 run(tmp2);
518
519 /*
520 * Walk from the tail to the head, free along the way.
521 */
522 for (; tmp2 != tmp; tmp--)
523 free(*tmp);
524 /*
525 * Now free the list itself.
526 */
527 free(tmp2);
528
529 /*
530 * Free the input line buffer, if we have one.
531 */
532 if (inpline != NULL) {
533 free(inpline);
534 inpline = NULL;
535 }
536 }
537
538 static void
run(char ** argv)539 run(char **argv)
540 {
541 pid_t pid;
542 int fd;
543 char **avec;
544
545 /*
546 * If the user wants to be notified of each command before it is
547 * executed, notify them. If they want the notification to be
548 * followed by a prompt, then prompt them.
549 */
550 if (tflag || pflag) {
551 (void)fprintf(stderr, "%s", *argv);
552 for (avec = argv + 1; *avec != NULL; ++avec)
553 (void)fprintf(stderr, " %s", *avec);
554 /*
555 * If the user has asked to be prompted, do so.
556 */
557 if (pflag)
558 /*
559 * If they asked not to exec, return without execution
560 * but if they asked to, go to the execution. If we
561 * could not open their tty, break the switch and drop
562 * back to -t behaviour.
563 */
564 switch (prompt()) {
565 case 0:
566 return;
567 case 1:
568 goto exec;
569 case 2:
570 break;
571 }
572 (void)fprintf(stderr, "\n");
573 (void)fflush(stderr);
574 }
575 exec:
576 childerr = 0;
577 switch (pid = vfork()) {
578 case -1:
579 warn("vfork");
580 xexit(*argv, 1);
581 case 0:
582 if (oflag) {
583 if ((fd = open(_PATH_TTY, O_RDONLY)) == -1)
584 err(1, "can't open /dev/tty");
585 } else {
586 fd = open(_PATH_DEVNULL, O_RDONLY);
587 }
588 if (fd > STDIN_FILENO) {
589 if (dup2(fd, STDIN_FILENO) != 0)
590 err(1, "can't dup2 to stdin");
591 close(fd);
592 }
593 execvp(argv[0], argv);
594 childerr = errno;
595 _exit(1);
596 }
597 pids_add(pid);
598 waitchildren(*argv, 0);
599 }
600
601 /*
602 * Wait for a tracked child to exit and return its pid and exit status.
603 *
604 * Ignores (discards) all untracked child processes.
605 * Returns -1 and sets errno to ECHILD if no tracked children exist.
606 * If block is set, waits indefinitely for a child process to exit.
607 * If block is not set and no children have exited, returns 0 immediately.
608 */
609 static pid_t
xwait(int block,int * status)610 xwait(int block, int *status) {
611 pid_t pid;
612
613 if (pids_empty()) {
614 errno = ECHILD;
615 return (-1);
616 }
617
618 while ((pid = waitpid(-1, status, block ? 0 : WNOHANG)) > 0)
619 if (pids_remove(pid))
620 break;
621
622 return (pid);
623 }
624
625 static void
xexit(const char * name,const int exit_code)626 xexit(const char *name, const int exit_code) {
627 waitchildren(name, 1);
628 exit(exit_code);
629 }
630
631 static void
waitchildren(const char * name,int waitall)632 waitchildren(const char *name, int waitall)
633 {
634 pid_t pid;
635 int status;
636 int cause_exit = 0;
637
638 while ((pid = xwait(waitall || pids_full(), &status)) > 0) {
639 /*
640 * If we couldn't invoke the utility or if utility exited
641 * because of a signal or with a value of 255, warn (per
642 * POSIX), and then wait until all other children have
643 * exited before exiting 1-125. POSIX requires us to stop
644 * reading if child exits because of a signal or with 255,
645 * but it does not require us to exit immediately; waiting
646 * is preferable to orphaning.
647 */
648 if (childerr != 0 && cause_exit == 0) {
649 errno = childerr;
650 waitall = 1;
651 cause_exit = ENOENT ? 127 : 126;
652 warn("%s", name);
653 } else if (WIFSIGNALED(status)) {
654 waitall = cause_exit = 1;
655 warnx("%s: terminated with signal %d; aborting",
656 name, WTERMSIG(status));
657 } else if (WEXITSTATUS(status) == 255) {
658 waitall = cause_exit = 1;
659 warnx("%s: exited with status 255; aborting", name);
660 } else if (WEXITSTATUS(status))
661 rval = 1;
662 }
663
664 if (cause_exit)
665 exit(cause_exit);
666 if (pid == -1 && errno != ECHILD)
667 err(1, "waitpid");
668 }
669
670 #define NOPID (0)
671
672 static void
pids_init(void)673 pids_init(void)
674 {
675 int i;
676
677 if ((childpids = malloc(maxprocs * sizeof(*childpids))) == NULL)
678 errx(1, "malloc failed");
679
680 for (i = 0; i < maxprocs; i++)
681 clearslot(i);
682 }
683
684 static int
pids_empty(void)685 pids_empty(void)
686 {
687
688 return (curprocs == 0);
689 }
690
691 static int
pids_full(void)692 pids_full(void)
693 {
694
695 return (curprocs >= maxprocs);
696 }
697
698 static void
pids_add(pid_t pid)699 pids_add(pid_t pid)
700 {
701 int slot;
702
703 slot = findfreeslot();
704 childpids[slot] = pid;
705 curprocs++;
706 }
707
708 static int
pids_remove(pid_t pid)709 pids_remove(pid_t pid)
710 {
711 int slot;
712
713 if ((slot = findslot(pid)) < 0)
714 return (0);
715
716 clearslot(slot);
717 curprocs--;
718 return (1);
719 }
720
721 static int
findfreeslot(void)722 findfreeslot(void)
723 {
724 int slot;
725
726 if ((slot = findslot(NOPID)) < 0)
727 errx(1, "internal error: no free pid slot");
728 return (slot);
729 }
730
731 static int
findslot(pid_t pid)732 findslot(pid_t pid)
733 {
734 int slot;
735
736 for (slot = 0; slot < maxprocs; slot++)
737 if (childpids[slot] == pid)
738 return (slot);
739 return (-1);
740 }
741
742 static void
clearslot(int slot)743 clearslot(int slot)
744 {
745
746 childpids[slot] = NOPID;
747 }
748
749 /*
750 * Prompt the user about running a command.
751 */
752 static int
prompt(void)753 prompt(void)
754 {
755 regex_t cre;
756 size_t rsize;
757 int match;
758 char *response;
759 FILE *ttyfp;
760
761 if ((ttyfp = fopen(_PATH_TTY, "r")) == NULL)
762 return (2); /* Indicate that the TTY failed to open. */
763 (void)fprintf(stderr, "?...");
764 (void)fflush(stderr);
765 if ((response = fgetln(ttyfp, &rsize)) == NULL ||
766 regcomp(&cre, nl_langinfo(YESEXPR), REG_BASIC) != 0) {
767 (void)fclose(ttyfp);
768 return (0);
769 }
770 response[rsize - 1] = '\0';
771 match = regexec(&cre, response, 0, NULL, 0);
772 (void)fclose(ttyfp);
773 regfree(&cre);
774 return (match == 0);
775 }
776
777 static void
usage(void)778 usage(void)
779 {
780
781 fprintf(stderr,
782 "usage: xargs [-0opt] [-E eofstr] [-I replstr [-R replacements] [-S replsize]]\n"
783 " [-J replstr] [-L number] [-n number [-x]] [-P maxprocs]\n"
784 " [-s size] [utility [argument ...]]\n");
785 exit(1);
786 }
787