aboutsummaryrefslogtreecommitdiff
path: root/findutils/xargs.c
blob: 8f0a3d4ad7cfff6eb7a9c582b8c709a729e13225 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
/* vi: set sw=4 ts=4: */
/*
 * Mini xargs implementation for busybox
 * Options are supported: "-prtx -n max_arg -s max_chars -e[ouf_str]"
 *
 * (C) 2002,2003 by Vladimir Oleynik <dzo@simtreas.ru>
 *
 * Special thanks
 * - Mark Whitley and Glenn McGrath for stimulus to rewrite :)
 * - Mike Rendell <michael@cs.mun.ca>
 * and David MacKenzie <djm@gnu.ai.mit.edu>.
 *
 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
 *
 * xargs is described in the Single Unix Specification v3 at
 * http://www.opengroup.org/onlinepubs/007904975/utilities/xargs.html
 *
 */

#include "libbb.h"

/* This is a NOEXEC applet. Be very careful! */


/* COMPAT:  SYSV version defaults size (and has a max value of) to 470.
   We try to make it as large as possible. */
#if !defined(ARG_MAX) && defined(_SC_ARG_MAX)
#define ARG_MAX sysconf (_SC_ARG_MAX)
#endif
#ifndef ARG_MAX
#define ARG_MAX 470
#endif


#ifdef TEST
# ifndef ENABLE_FEATURE_XARGS_SUPPORT_CONFIRMATION
#  define ENABLE_FEATURE_XARGS_SUPPORT_CONFIRMATION 1
# endif
# ifndef ENABLE_FEATURE_XARGS_SUPPORT_QUOTES
#  define ENABLE_FEATURE_XARGS_SUPPORT_QUOTES 1
# endif
# ifndef ENABLE_FEATURE_XARGS_SUPPORT_TERMOPT
#  define ENABLE_FEATURE_XARGS_SUPPORT_TERMOPT 1
# endif
# ifndef ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM
#  define ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM 1
# endif
#endif

/*
   This function has special algorithm.
   Don't use fork and include to main!
*/
static int xargs_exec(char **args)
{
	int status;

	status = spawn_and_wait(args);
	if (status < 0) {
		bb_simple_perror_msg(args[0]);
		return errno == ENOENT ? 127 : 126;
	}
	if (status == 255) {
		bb_error_msg("%s: exited with status 255; aborting", args[0]);
		return 124;
	}
/* Huh? I think we won't see this, ever. We don't wait with WUNTRACED!
	if (WIFSTOPPED(status)) {
		bb_error_msg("%s: stopped by signal %d",
			args[0], WSTOPSIG(status));
		return 125;
	}
*/
	if (status >= 1000) {
		bb_error_msg("%s: terminated by signal %d",
			args[0], status - 1000);
		return 125;
	}
	if (status)
		return 123;
	return 0;
}


typedef struct xlist_t {
	struct xlist_t *link;
	size_t length;
	char xstr[1];
} xlist_t;

static smallint eof_stdin_detected;

#define ISBLANK(c) ((c) == ' ' || (c) == '\t')
#define ISSPACE(c) (ISBLANK(c) || (c) == '\n' || (c) == '\r' \
		    || (c) == '\f' || (c) == '\v')

#if ENABLE_FEATURE_XARGS_SUPPORT_QUOTES
static xlist_t *process_stdin(xlist_t *list_arg,
	const char *eof_str, size_t mc, char *buf)
{
#define NORM      0
#define QUOTE     1
#define BACKSLASH 2
#define SPACE     4

	char *s = NULL;         /* start word */
	char *p = NULL;         /* pointer to end word */
	char q = '\0';          /* quote char */
	char state = NORM;
	char eof_str_detected = 0;
	size_t line_l = 0;      /* size loaded args line */
	int c;                  /* current char */
	xlist_t *cur;
	xlist_t *prev;

	prev = cur = list_arg;
	while (1) {
		if (!cur) break;
		prev = cur;
		line_l += cur->length;
		cur = cur->link;
	}

	while (!eof_stdin_detected) {
		c = getchar();
		if (c == EOF) {
			eof_stdin_detected = 1;
			if (s)
				goto unexpected_eof;
			break;
		}
		if (eof_str_detected)
			continue;
		if (state == BACKSLASH) {
			state = NORM;
			goto set;
		} else if (state == QUOTE) {
			if (c != q)
				goto set;
			q = '\0';
			state = NORM;
		} else { /* if (state == NORM) */
			if (ISSPACE(c)) {
				if (s) {
 unexpected_eof:
					state = SPACE;
					c = '\0';
					goto set;
				}
			} else {
				if (s == NULL)
					s = p = buf;
				if (c == '\\') {
					state = BACKSLASH;
				} else if (c == '\'' || c == '"') {
					q = c;
					state = QUOTE;
				} else {
 set:
					if ((size_t)(p - buf) >= mc)
						bb_error_msg_and_die("argument line too long");
					*p++ = c;
				}
			}
		}
		if (state == SPACE) {   /* word's delimiter or EOF detected */
			if (q) {
				bb_error_msg_and_die("unmatched %s quote",
					q == '\'' ? "single" : "double");
			}
			/* word loaded */
			if (eof_str) {
				eof_str_detected = (strcmp(s, eof_str) == 0);
			}
			if (!eof_str_detected) {
				size_t length = (p - buf);
				/* Dont xzalloc - it can be quite big */
				cur = xmalloc(offsetof(xlist_t, xstr) + length);
				cur->link = NULL;
				cur->length = length;
				memcpy(cur->xstr, s, length);
				if (prev == NULL) {
					list_arg = cur;
				} else {
					prev->link = cur;
				}
				prev = cur;
				line_l += length;
				if (line_l > mc) {
					/* stop memory usage :-) */
					break;
				}
			}
			s = NULL;
			state = NORM;
		}
	}
	return list_arg;
}
#else
/* The variant does not support single quotes, double quotes or backslash */
static xlist_t *process_stdin(xlist_t *list_arg,
		const char *eof_str, size_t mc, char *buf)
{

	int c;                  /* current char */
	char eof_str_detected = 0;
	char *s = NULL;         /* start word */
	char *p = NULL;         /* pointer to end word */
	size_t line_l = 0;      /* size loaded args line */
	xlist_t *cur;
	xlist_t *prev;

	prev = cur = list_arg;
	while (1) {
		if (!cur) break;
		prev = cur;
		line_l += cur->length;
		cur = cur->link;
	}

	while (!eof_stdin_detected) {
		c = getchar();
		if (c == EOF) {
			eof_stdin_detected = 1;
		}
		if (eof_str_detected)
			continue;
		if (c == EOF || ISSPACE(c)) {
			if (s == NULL)
				continue;
			c = EOF;
		}
		if (s == NULL)
			s = p = buf;
		if ((size_t)(p - buf) >= mc)
			bb_error_msg_and_die("argument line too long");
		*p++ = (c == EOF ? '\0' : c);
		if (c == EOF) { /* word's delimiter or EOF detected */
			/* word loaded */
			if (eof_str) {
				eof_str_detected = (strcmp(s, eof_str) == 0);
			}
			if (!eof_str_detected) {
				size_t length = (p - buf);
				/* Dont xzalloc - it can be quite big */
				cur = xmalloc(offsetof(xlist_t, xstr) + length);
				cur->link = NULL;
				cur->length = length;
				memcpy(cur->xstr, s, length);
				if (prev == NULL) {
					list_arg = cur;
				} else {
					prev->link = cur;
				}
				prev = cur;
				line_l += length;
				if (line_l > mc) {
					/* stop memory usage :-) */
					break;
				}
				s = NULL;
			}
		}
	}
	return list_arg;
}
#endif /* FEATURE_XARGS_SUPPORT_QUOTES */


#if ENABLE_FEATURE_XARGS_SUPPORT_CONFIRMATION
/* Prompt the user for a response, and
   if the user responds affirmatively, return true;
   otherwise, return false. Uses "/dev/tty", not stdin. */
static int xargs_ask_confirmation(void)
{
	FILE *tty_stream;
	int c, savec;

	tty_stream = xfopen_for_read(CURRENT_TTY);
	fputs(" ?...", stderr);
	fflush(stderr);
	c = savec = getc(tty_stream);
	while (c != EOF && c != '\n')
		c = getc(tty_stream);
	fclose(tty_stream);
	return (savec == 'y' || savec == 'Y');
}
#else
# define xargs_ask_confirmation() 1
#endif /* FEATURE_XARGS_SUPPORT_CONFIRMATION */

#if ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM
static xlist_t *process0_stdin(xlist_t *list_arg,
		const char *eof_str UNUSED_PARAM, size_t mc, char *buf)
{
	int c;                  /* current char */
	char *s = NULL;         /* start word */
	char *p = NULL;         /* pointer to end word */
	size_t line_l = 0;      /* size loaded args line */
	xlist_t *cur;
	xlist_t *prev;

	prev = cur = list_arg;
	while (1) {
		if (!cur) break;
		prev = cur;
		line_l += cur->length;
		cur = cur->link;
	}

	while (!eof_stdin_detected) {
		c = getchar();
		if (c == EOF) {
			eof_stdin_detected = 1;
			if (s == NULL)
				break;
			c = '\0';
		}
		if (s == NULL)
			s = p = buf;
		if ((size_t)(p - buf) >= mc)
			bb_error_msg_and_die("argument line too long");
		*p++ = c;
		if (c == '\0') {   /* word's delimiter or EOF detected */
			/* word loaded */
			size_t length = (p - buf);
			/* Dont xzalloc - it can be quite big */
			cur = xmalloc(offsetof(xlist_t, xstr) + length);
			cur->link = NULL;
			cur->length = length;
			memcpy(cur->xstr, s, length);
			if (prev == NULL) {
				list_arg = cur;
			} else {
				prev->link = cur;
			}
			prev = cur;
			line_l += length;
			if (line_l > mc) {
				/* stop memory usage :-) */
				break;
			}
			s = NULL;
		}
	}
	return list_arg;
}
#endif /* FEATURE_XARGS_SUPPORT_ZERO_TERM */

/* Correct regardless of combination of CONFIG_xxx */
enum {
	OPTBIT_VERBOSE = 0,
	OPTBIT_NO_EMPTY,
	OPTBIT_UPTO_NUMBER,
	OPTBIT_UPTO_SIZE,
	OPTBIT_EOF_STRING,
	USE_FEATURE_XARGS_SUPPORT_CONFIRMATION(OPTBIT_INTERACTIVE,)
	USE_FEATURE_XARGS_SUPPORT_TERMOPT(     OPTBIT_TERMINATE  ,)
	USE_FEATURE_XARGS_SUPPORT_ZERO_TERM(   OPTBIT_ZEROTERM   ,)

	OPT_VERBOSE     = 1<<OPTBIT_VERBOSE    ,
	OPT_NO_EMPTY    = 1<<OPTBIT_NO_EMPTY   ,
	OPT_UPTO_NUMBER = 1<<OPTBIT_UPTO_NUMBER,
	OPT_UPTO_SIZE   = 1<<OPTBIT_UPTO_SIZE  ,
	OPT_EOF_STRING  = 1<<OPTBIT_EOF_STRING ,
	OPT_INTERACTIVE = USE_FEATURE_XARGS_SUPPORT_CONFIRMATION((1<<OPTBIT_INTERACTIVE)) + 0,
	OPT_TERMINATE   = USE_FEATURE_XARGS_SUPPORT_TERMOPT(     (1<<OPTBIT_TERMINATE  )) + 0,
	OPT_ZEROTERM    = USE_FEATURE_XARGS_SUPPORT_ZERO_TERM(   (1<<OPTBIT_ZEROTERM   )) + 0,
};
#define OPTION_STR "+trn:s:e::" \
	USE_FEATURE_XARGS_SUPPORT_CONFIRMATION("p") \
	USE_FEATURE_XARGS_SUPPORT_TERMOPT(     "x") \
	USE_FEATURE_XARGS_SUPPORT_ZERO_TERM(   "0")

int xargs_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int xargs_main(int argc, char **argv)
{
	char **args;
	int i, n;
	xlist_t *list = NULL;
	xlist_t *cur;
	int child_error = 0;
	char *max_args, *max_chars;
	int n_max_arg;
	size_t n_chars = 0;
	long orig_arg_max;
	const char *eof_str = "_";
	unsigned opt;
	size_t n_max_chars;
#if ENABLE_FEATURE_XARGS_SUPPORT_ZERO_TERM
	xlist_t* (*read_args)(xlist_t*, const char*, size_t, char*) = process_stdin;
#else
#define read_args process_stdin
#endif

	opt = getopt32(argv, OPTION_STR, &max_args, &max_chars, &eof_str);

	if (opt & OPT_ZEROTERM)
		USE_FEATURE_XARGS_SUPPORT_ZERO_TERM(read_args = process0_stdin);

	argv += optind;
	argc -= optind;
	if (!argc) {
		/* default behavior is to echo all the filenames */
		*argv = (char*)"echo";
		argc++;
	}

	orig_arg_max = ARG_MAX;
	if (orig_arg_max == -1)
		orig_arg_max = LONG_MAX;
	orig_arg_max -= 2048;   /* POSIX.2 requires subtracting 2048 */

	if (opt & OPT_UPTO_SIZE) {
		n_max_chars = xatoul_range(max_chars, 1, orig_arg_max);
		for (i = 0; i < argc; i++) {
			n_chars += strlen(*argv) + 1;
		}
		if (n_max_chars < n_chars) {
			bb_error_msg_and_die("cannot fit single argument within argument list size limit");
		}
		n_max_chars -= n_chars;
	} else {
		/* Sanity check for systems with huge ARG_MAX defines (e.g., Suns which
		   have it at 1 meg).  Things will work fine with a large ARG_MAX but it
		   will probably hurt the system more than it needs to; an array of this
		   size is allocated.  */
		if (orig_arg_max > 20 * 1024)
			orig_arg_max = 20 * 1024;
		n_max_chars = orig_arg_max;
	}
	max_chars = xmalloc(n_max_chars);

	if (opt & OPT_UPTO_NUMBER) {
		n_max_arg = xatoul_range(max_args, 1, INT_MAX);
	} else {
		n_max_arg = n_max_chars;
	}

	while ((list = read_args(list, eof_str, n_max_chars, max_chars)) != NULL ||
		!(opt & OPT_NO_EMPTY))
	{
		opt |= OPT_NO_EMPTY;
		n = 0;
		n_chars = 0;
#if ENABLE_FEATURE_XARGS_SUPPORT_TERMOPT
		for (cur = list; cur;) {
			n_chars += cur->length;
			n++;
			cur = cur->link;
			if (n_chars > n_max_chars || (n == n_max_arg && cur)) {
				if (opt & OPT_TERMINATE)
					bb_error_msg_and_die("argument list too long");
				break;
			}
		}
#else
		for (cur = list; cur; cur = cur->link) {
			n_chars += cur->length;
			n++;
			if (n_chars > n_max_chars || n == n_max_arg) {
				break;
			}
		}
#endif /* FEATURE_XARGS_SUPPORT_TERMOPT */

		/* allocate pointers for execvp:
		   argc*arg, n*arg from stdin, NULL */
		args = xzalloc((n + argc + 1) * sizeof(char *));

		/* store the command to be executed
		   (taken from the command line) */
		for (i = 0; i < argc; i++)
			args[i] = argv[i];
		/* (taken from stdin) */
		for (cur = list; n; cur = cur->link) {
			args[i++] = cur->xstr;
			n--;
		}

		if (opt & (OPT_INTERACTIVE | OPT_VERBOSE)) {
			for (i = 0; args[i]; i++) {
				if (i)
					fputc(' ', stderr);
				fputs(args[i], stderr);
			}
			if (!(opt & OPT_INTERACTIVE))
				fputc('\n', stderr);
		}
		if (!(opt & OPT_INTERACTIVE) || xargs_ask_confirmation()) {
			child_error = xargs_exec(args);
		}

		/* clean up */
		for (i = argc; args[i]; i++) {
			cur = list;
			list = list->link;
			free(cur);
		}
		free(args);
		if (child_error > 0 && child_error != 123) {
			break;
		}
	} /* while */
	if (ENABLE_FEATURE_CLEAN_UP)
		free(max_chars);
	return child_error;
}


#ifdef TEST

const char *applet_name = "debug stuff usage";

void bb_show_usage(void)
{
	fprintf(stderr, "Usage: %s [-p] [-r] [-t] -[x] [-n max_arg] [-s max_chars]\n",
		applet_name);
	exit(EXIT_FAILURE);
}

int main(int argc, char **argv)
{
	return xargs_main(argc, argv);
}
#endif /* TEST */