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 * 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.
23 *
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
34 * SUCH DAMAGE.
35 *
36 * $xMach: xargs.c,v 1.6 2002/02/23 05:27:47 tim Exp $
37 */
38
39#if 0
40#ifndef lint
41static const char copyright[] =
42"@(#) Copyright (c) 1990, 1993\n\
43	The Regents of the University of California.  All rights reserved.\n";
44#endif /* not lint */
45
46#ifndef lint
47static char sccsid[] = "@(#)xargs.c	8.1 (Berkeley) 6/6/93";
48#endif /* not lint */
49#endif
50#include <sys/cdefs.h>
51__FBSDID("$FreeBSD: src/usr.bin/xargs/xargs.c,v 1.57 2005/02/27 02:01:31 gad Exp $");
52
53#include <sys/param.h>
54#include <sys/wait.h>
55
56#include <err.h>
57#include <errno.h>
58#include <fcntl.h>
59#include <langinfo.h>
60#include <locale.h>
61#include <paths.h>
62#include <regex.h>
63#include <stdio.h>
64#include <stdlib.h>
65#include <string.h>
66#include <unistd.h>
67
68#include "pathnames.h"
69
70#ifdef __APPLE__
71#include <get_compat.h>
72#else
73#define COMPAT_MODE(a,b) (1)
74#endif /* __APPLE__ */
75
76static void	parse_input(int, char *[]);
77static void	prerun(int, char *[]);
78static int	prompt(void);
79static void	run(char **);
80static void	usage(void);
81void		strnsubst(char **, const char *, const char *, size_t);
82static void	waitchildren(const char *, int);
83
84static int last_was_newline = 1;
85static int last_was_blank = 0;
86
87static char echo[] = _PATH_ECHO;
88static char **av, **bxp, **ep, **endxp, **xp;
89static char *argp, *bbp, *ebp, *inpline, *p, *replstr;
90static const char *eofstr;
91static int count, insingle, indouble, oflag, pflag, tflag, Rflag, rval, zflag;
92static int cnt, Iflag, jfound, Lflag, wasquoted, xflag;
93static int curprocs, maxprocs;
94static size_t pad9314053;
95
96static volatile int childerr;
97
98extern char **environ;
99
100int
101main(int argc, char *argv[])
102{
103	long arg_max;
104	int ch, Jflag, nflag, nline;
105	size_t nargs;
106	size_t linelen;
107	char *endptr;
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 - MAXPATHLEN; /* for argv[0] from execvp() */
133	pad9314053 = sizeof(char *); /* reserve for string area rounding */
134	while (*ep != NULL) {
135		/* 1 byte for each '\0' */
136		nline -= strlen(*ep++) + 1 + sizeof(*ep);
137	}
138	nline -= pad9314053;
139	maxprocs = 1;
140	while ((ch = getopt(argc, argv, "0E:I:J:L:n:oP:pR:s:tx")) != -1)
141		switch(ch) {
142		case 'E':
143			eofstr = optarg;
144			break;
145		case 'I':
146			Jflag = 0;
147			Iflag = 1;
148			Lflag = 1;
149			replstr = optarg;
150			break;
151		case 'J':
152			Iflag = 0;
153			Jflag = 1;
154			replstr = optarg;
155			break;
156		case 'L':
157			Lflag = atoi(optarg);
158			if (COMPAT_MODE("bin/xargs", "Unix2003")) {
159				nflag = 0; /* Override */
160				nargs = 5000;
161			}
162			break;
163		case 'n':
164			nflag = 1;
165			if ((nargs = strtol(optarg, NULL, 10)) <= 0)
166				errx(1, "illegal argument count");
167			if (COMPAT_MODE("bin/xargs", "Unix2003")) {
168				Lflag = 0; /* Override */
169			}
170			break;
171		case 'o':
172			oflag = 1;
173			break;
174		case 'P':
175			if ((maxprocs = atoi(optarg)) <= 0)
176				errx(1, "max. processes must be >0");
177			break;
178		case 'p':
179			pflag = 1;
180			break;
181		case 'R':
182			Rflag = strtol(optarg, &endptr, 10);
183			if (*endptr != '\0')
184				errx(1, "replacements must be a number");
185			break;
186		case 's':
187			nline = atoi(optarg);
188			pad9314053 = 0; /* assume the -s value is valid */
189			break;
190		case 't':
191			tflag = 1;
192			break;
193		case 'x':
194			xflag = 1;
195			break;
196		case '0':
197			zflag = 1;
198			break;
199		case '?':
200		default:
201			usage();
202	}
203	argc -= optind;
204	argv += optind;
205
206	if (!Iflag && Rflag)
207		usage();
208	if (Iflag && !Rflag)
209		Rflag = 5;
210	if (xflag && !nflag)
211		usage();
212	if (Iflag || Lflag)
213		xflag = 1;
214	if (replstr != NULL && *replstr == '\0')
215		errx(1, "replstr may not be empty");
216
217	/*
218	 * Allocate pointers for the utility name, the utility arguments,
219	 * the maximum arguments to be read from stdin and the trailing
220	 * NULL.
221	 */
222	linelen = 1 + argc + nargs + 1;
223	if ((av = bxp = malloc(linelen * sizeof(char **))) == NULL)
224		errx(1, "malloc failed");
225
226	/*
227	 * Use the user's name for the utility as argv[0], just like the
228	 * shell.  Echo is the default.  Set up pointers for the user's
229	 * arguments.
230	 */
231	if (*argv == NULL)
232		cnt = strlen(*bxp++ = echo) + pad9314053;
233	else {
234		do {
235			if (Jflag && strcmp(*argv, replstr) == 0) {
236				char **avj;
237				jfound = 1;
238				argv++;
239				for (avj = argv; *avj; avj++)
240					cnt += strlen(*avj) + 1 + pad9314053;
241				break;
242			}
243			cnt += strlen(*bxp++ = *argv) + 1 + pad9314053;
244		} while (*++argv != NULL);
245	}
246
247	/*
248	 * Set up begin/end/traversing pointers into the array.  The -n
249	 * count doesn't include the trailing NULL pointer, so the malloc
250	 * added in an extra slot.
251	 */
252	endxp = (xp = bxp) + nargs;
253
254	/*
255	 * Allocate buffer space for the arguments read from stdin and the
256	 * trailing NULL.  Buffer space is defined as the default or specified
257	 * space, minus the length of the utility name and arguments.  Set up
258	 * begin/end/traversing pointers into the array.  The -s count does
259	 * include the trailing NULL, so the malloc didn't add in an extra
260	 * slot.
261	 */
262	nline -= cnt;
263	if (nline <= 0)
264		errx(1, "insufficient space for command");
265
266	if ((bbp = malloc((size_t)(nline + 1))) == NULL)
267		errx(1, "malloc failed");
268	ebp = (argp = p = bbp) + nline - 1;
269	for (;;)
270		parse_input(argc, argv);
271}
272
273static void
274parse_input(int argc, char *argv[])
275{
276	int ch, foundeof;
277	char **avj;
278	int last_was_backslashed = 0;
279
280	foundeof = 0;
281
282	switch(ch = getchar()) {
283	case EOF:
284		/* No arguments since last exec. */
285		if (p == bbp) {
286			waitchildren(*argv, 1);
287			exit(rval);
288		}
289		goto arg1;
290	case ' ':
291		last_was_blank = 1;
292	case '\t':
293		/* Quotes escape tabs and spaces. */
294		if (insingle || indouble || zflag)
295			goto addch;
296		goto arg2;
297	case '\0':
298		if (zflag) {
299			/*
300			 * Increment 'count', so that nulls will be treated
301			 * as end-of-line, as well as end-of-argument.  This
302			 * is needed so -0 works properly with -I and -L.
303			 */
304			count++;
305			goto arg2;
306		}
307		goto addch;
308	case '\n':
309		if (zflag)
310			goto addch;
311		if (COMPAT_MODE("bin/xargs", "Unix2003")) {
312			if (last_was_newline) {
313				/* don't count empty line */
314				break;
315			}
316			if (!last_was_blank ) {
317				/* only count if NOT continuation line */
318				count++;
319			}
320		} else {
321			count++;
322		}
323		last_was_newline = 1;
324
325		/* Quotes do not escape newlines. */
326arg1:		if (insingle || indouble)
327			errx(1, "unterminated quote");
328arg2:
329		foundeof = *eofstr != '\0' &&
330		    strcmp(argp, eofstr) == 0;
331
332#ifdef __APPLE__
333		/* 6591323: -I specifies that it processes the entire line,
334		 * so only recognize eofstr at the end of a line. */
335		if (Iflag && !last_was_newline)
336			foundeof = 0;
337
338		/* 6591323: Essentially the same as the EOF handling above. */
339		if (foundeof && (p - strlen(eofstr) == bbp)) {
340			waitchildren(*argv, 1);
341			exit(rval);
342		}
343#endif
344
345		/* Do not make empty args unless they are quoted */
346		if ((argp != p || wasquoted) && !foundeof) {
347			*p++ = '\0';
348			*xp++ = argp;
349			if (Iflag) {
350				size_t curlen;
351
352				if (inpline == NULL)
353					curlen = 0;
354				else {
355					/*
356					 * If this string is not zero
357					 * length, append a space for
358					 * separation before the next
359					 * argument.
360					 */
361					if ((curlen = strlen(inpline)))
362						strcat(inpline, " ");
363				}
364				curlen++;
365				/*
366				 * Allocate enough to hold what we will
367				 * be holding in a second, and to append
368				 * a space next time through, if we have
369				 * to.
370				 */
371				inpline = realloc(inpline, curlen + 2 +
372				    strlen(argp));
373				if (inpline == NULL)
374					errx(1, "realloc failed");
375				if (curlen == 1)
376					strcpy(inpline, argp);
377				else
378					strcat(inpline, argp);
379			}
380		}
381
382		/*
383		 * If max'd out on args or buffer, or reached EOF,
384		 * run the command.  If xflag and max'd out on buffer
385		 * but not on args, object.  Having reached the limit
386		 * of input lines, as specified by -L is the same as
387		 * maxing out on arguments.
388		 */
389		if (xp == endxp || p + (count * pad9314053) > ebp || ch == EOF ||
390		    (Lflag <= count && xflag) || foundeof) {
391			if (xflag && xp != endxp && p + (count * pad9314053) > ebp)
392				errx(1, "insufficient space for arguments");
393			if (jfound) {
394				for (avj = argv; *avj; avj++)
395					*xp++ = *avj;
396			}
397			prerun(argc, av);
398			if (ch == EOF || foundeof) {
399				waitchildren(*argv, 1);
400				exit(rval);
401			}
402			p = bbp;
403			xp = bxp;
404			count = 0;
405		}
406		argp = p;
407		wasquoted = 0;
408		break;
409	case '\'':
410		if (indouble || zflag)
411			goto addch;
412		insingle = !insingle;
413		wasquoted = 1;
414		break;
415	case '"':
416		if (insingle || zflag)
417			goto addch;
418		indouble = !indouble;
419		wasquoted = 1;
420		break;
421	case '\\':
422		last_was_backslashed = 1;
423		if (zflag)
424			goto addch;
425		/* Backslash escapes anything, is escaped by quotes. */
426		if (!insingle && !indouble && (ch = getchar()) == EOF)
427			errx(1, "backslash at EOF");
428		/* FALLTHROUGH */
429	default:
430addch:		if (p < ebp) {
431			*p++ = ch;
432			break;
433		}
434
435		/* If only one argument, not enough buffer space. */
436		if (bxp == xp)
437			errx(1, "insufficient space for argument");
438		/* Didn't hit argument limit, so if xflag object. */
439		if (xflag)
440			errx(1, "insufficient space for arguments");
441
442		if (jfound) {
443			for (avj = argv; *avj; avj++)
444				*xp++ = *avj;
445		}
446		prerun(argc, av);
447		xp = bxp;
448		cnt = ebp - argp;
449		memcpy(bbp, argp, (size_t)cnt);
450		p = (argp = bbp) + cnt;
451		*p++ = ch;
452		break;
453	}
454	if (ch != ' ')
455		last_was_blank = 0;
456	if (ch != '\n' || last_was_backslashed)
457		last_was_newline = 0;
458}
459
460/*
461 * Do things necessary before run()'ing, such as -I substitution,
462 * and then call run().
463 */
464static void
465prerun(int argc, char *argv[])
466{
467	char **tmp, **tmp2, **avj;
468	int repls;
469
470	repls = Rflag;
471
472	if (argc == 0 || repls == 0) {
473		*xp = NULL;
474		run(argv);
475		return;
476	}
477
478	avj = argv;
479
480	/*
481	 * Allocate memory to hold the argument list, and
482	 * a NULL at the tail.
483	 */
484	tmp = malloc((argc + 1) * sizeof(char**));
485	if (tmp == NULL)
486		errx(1, "malloc failed");
487	tmp2 = tmp;
488
489	/*
490	 * Save the first argument and iterate over it, we
491	 * cannot do strnsubst() to it.
492	 */
493	if ((*tmp++ = strdup(*avj++)) == NULL)
494		errx(1, "strdup failed");
495
496	/*
497	 * For each argument to utility, if we have not used up
498	 * the number of replacements we are allowed to do, and
499	 * if the argument contains at least one occurrence of
500	 * replstr, call strnsubst(), else just save the string.
501	 * Iterations over elements of avj and tmp are done
502	 * where appropriate.
503	 */
504	while (--argc) {
505		*tmp = *avj++;
506		if (repls && strstr(*tmp, replstr) != NULL) {
507			strnsubst(tmp++, replstr, inpline, (size_t)255);
508			if (repls > 0)
509				repls--;
510		} else {
511			if ((*tmp = strdup(*tmp)) == NULL)
512				errx(1, "strdup failed");
513			tmp++;
514		}
515	}
516
517	/*
518	 * Run it.
519	 */
520	*tmp = NULL;
521	run(tmp2);
522
523	/*
524	 * Walk from the tail to the head, free along the way.
525	 */
526	for (; tmp2 != tmp; tmp--)
527		free(*tmp);
528	/*
529	 * Now free the list itself.
530	 */
531	free(tmp2);
532
533	/*
534	 * Free the input line buffer, if we have one.
535	 */
536	if (inpline != NULL) {
537		free(inpline);
538		inpline = NULL;
539	}
540}
541
542static void
543run(char **argv)
544{
545	pid_t pid;
546	int fd;
547	char **avec;
548
549	/*
550	 * If the user wants to be notified of each command before it is
551	 * executed, notify them.  If they want the notification to be
552	 * followed by a prompt, then prompt them.
553	 */
554	if (tflag || pflag) {
555		(void)fprintf(stderr, "%s", *argv);
556		for (avec = argv + 1; *avec != NULL; ++avec)
557			(void)fprintf(stderr, " %s", *avec);
558		/*
559		 * If the user has asked to be prompted, do so.
560		 */
561		if (pflag)
562			/*
563			 * If they asked not to exec, return without execution
564			 * but if they asked to, go to the execution.  If we
565			 * could not open their tty, break the switch and drop
566			 * back to -t behaviour.
567			 */
568			switch (prompt()) {
569			case 0:
570				return;
571			case 1:
572				goto exec;
573			case 2:
574				break;
575			}
576		(void)fprintf(stderr, "\n");
577		(void)fflush(stderr);
578	}
579exec:
580	childerr = 0;
581	switch(pid = vfork()) {
582	case -1:
583		err(1, "vfork");
584	case 0:
585		if (oflag) {
586			if ((fd = open(_PATH_TTY, O_RDONLY)) == -1)
587				err(1, "can't open /dev/tty");
588		} else {
589			fd = open(_PATH_DEVNULL, O_RDONLY);
590		}
591		if (fd > STDIN_FILENO) {
592			if (dup2(fd, STDIN_FILENO) != 0)
593				err(1, "can't dup2 to stdin");
594			close(fd);
595		}
596		execvp(argv[0], argv);
597		childerr = errno;
598		_exit(1);
599	}
600	curprocs++;
601	waitchildren(*argv, 0);
602}
603
604static void
605waitchildren(const char *name, int waitall)
606{
607	pid_t pid;
608	int status;
609
610	while ((pid = waitpid(-1, &status, !waitall && curprocs < maxprocs ?
611	    WNOHANG : 0)) > 0) {
612		curprocs--;
613		/* If we couldn't invoke the utility, exit. */
614		if (childerr != 0) {
615			errno = childerr;
616			err(errno == ENOENT ? 127 : 126, "%s", name);
617		}
618		/*
619		 * If utility signaled or exited with a value of 255,
620		 * exit 1-125.
621		 */
622		if (WIFSIGNALED(status) || WEXITSTATUS(status) == 255)
623			exit(1);
624		if (WEXITSTATUS(status))
625			rval = 1;
626	}
627	if (pid == -1 && errno != ECHILD)
628		err(1, "wait3");
629}
630
631/*
632 * Prompt the user about running a command.
633 */
634static int
635prompt(void)
636{
637	regex_t cre;
638	size_t rsize;
639	int match;
640	char *response;
641	FILE *ttyfp;
642
643	if ((ttyfp = fopen(_PATH_TTY, "r")) == NULL)
644		return (2);	/* Indicate that the TTY failed to open. */
645	(void)fprintf(stderr, "?...");
646	(void)fflush(stderr);
647	if ((response = fgetln(ttyfp, &rsize)) == NULL ||
648	    regcomp(&cre, nl_langinfo(YESEXPR), REG_BASIC) != 0) {
649		(void)fclose(ttyfp);
650		return (0);
651	}
652	match = regexec(&cre, response, 0, NULL, 0);
653	(void)fclose(ttyfp);
654	regfree(&cre);
655	return (match == 0);
656}
657
658static void
659usage(void)
660{
661	fprintf(stderr,
662"usage: xargs [-0opt] [-E eofstr] [-I replstr [-R replacements]] [-J replstr]\n"
663"             [-L number] [-n number [-x]] [-P maxprocs] [-s size]\n"
664"             [utility [argument ...]]\n");
665	exit(1);
666}
667