aboutsummaryrefslogtreecommitdiff
path: root/findutils/grep.c
blob: be290118fbf68fb010fbed8a1081733af73451d8 (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
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
/* vi: set sw=4 ts=4: */
/*
 * Mini grep implementation for busybox using libc regex.
 *
 * Copyright (C) 1999,2000,2001 by Lineo, inc. and Mark Whitley
 * Copyright (C) 1999,2000,2001 by Mark Whitley <markw@codepoet.org>
 *
 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
 */
/* BB_AUDIT SUSv3 defects - unsupported option -x "match whole line only". */
/* BB_AUDIT GNU defects - always acts as -a.  */
/* http://www.opengroup.org/onlinepubs/007904975/utilities/grep.html */
/*
 * 2004,2006 (C) Vladimir Oleynik <dzo@simtreas.ru> -
 * correction "-e pattern1 -e pattern2" logic and more optimizations.
 * precompiled regex
 */
/*
 * (C) 2006 Jac Goudsmit added -o option
 */

//kbuild:lib-$(CONFIG_GREP) += grep.o
//config:
//config:config GREP
//config:	bool "grep"
//config:	default n
//config:	help
//config:	  grep is used to search files for a specified pattern.
//config:
//config:config FEATURE_GREP_EGREP_ALIAS
//config:	bool "Enable extended regular expressions (egrep & grep -E)"
//config:	default y
//config:	depends on GREP
//config:	help
//config:	  Enabled support for extended regular expressions. Extended
//config:	  regular expressions allow for alternation (foo|bar), grouping,
//config:	  and various repetition operators.
//config:
//config:config FEATURE_GREP_FGREP_ALIAS
//config:	bool "Alias fgrep to grep -F"
//config:	default y
//config:	depends on GREP
//config:	help
//config:	  fgrep sees the search pattern as a normal string rather than
//config:	  regular expressions.
//config:	  grep -F always works, this just creates the fgrep alias.
//config:
//config:config FEATURE_GREP_CONTEXT
//config:	bool "Enable before and after context flags (-A, -B and -C)"
//config:	default y
//config:	depends on GREP
//config:	help
//config:	  Print the specified number of leading (-B) and/or trailing (-A)
//config:	  context surrounding our matching lines.
//config:	  Print the specified number of context lines (-C).

#include "libbb.h"
#include "xregex.h"

/* options */
#define OPTSTR_GREP \
	"lnqvscFiHhe:f:Lorm:w" \
	IF_FEATURE_GREP_CONTEXT("A:B:C:") \
	IF_FEATURE_GREP_EGREP_ALIAS("E") \
	IF_EXTRA_COMPAT("z") \
	"aI"

/* ignored: -a "assume all files to be text" */
/* ignored: -I "assume binary files have no matches" */

enum {
	OPTBIT_l, /* list matched file names only */
	OPTBIT_n, /* print line# */
	OPTBIT_q, /* quiet - exit(EXIT_SUCCESS) of first match */
	OPTBIT_v, /* invert the match, to select non-matching lines */
	OPTBIT_s, /* suppress errors about file open errors */
	OPTBIT_c, /* count matches per file (suppresses normal output) */
	OPTBIT_F, /* literal match */
	OPTBIT_i, /* case-insensitive */
	OPTBIT_H, /* force filename display */
	OPTBIT_h, /* inhibit filename display */
	OPTBIT_e, /* -e PATTERN */
	OPTBIT_f, /* -f FILE_WITH_PATTERNS */
	OPTBIT_L, /* list unmatched file names only */
	OPTBIT_o, /* show only matching parts of lines */
	OPTBIT_r, /* recurse dirs */
	OPTBIT_m, /* -m MAX_MATCHES */
	OPTBIT_w, /* -w whole word match */
	IF_FEATURE_GREP_CONTEXT(    OPTBIT_A ,) /* -A NUM: after-match context */
	IF_FEATURE_GREP_CONTEXT(    OPTBIT_B ,) /* -B NUM: before-match context */
	IF_FEATURE_GREP_CONTEXT(    OPTBIT_C ,) /* -C NUM: -A and -B combined */
	IF_FEATURE_GREP_EGREP_ALIAS(OPTBIT_E ,) /* extended regexp */
	IF_EXTRA_COMPAT(            OPTBIT_z ,) /* input is NUL terminated */
	OPT_l = 1 << OPTBIT_l,
	OPT_n = 1 << OPTBIT_n,
	OPT_q = 1 << OPTBIT_q,
	OPT_v = 1 << OPTBIT_v,
	OPT_s = 1 << OPTBIT_s,
	OPT_c = 1 << OPTBIT_c,
	OPT_F = 1 << OPTBIT_F,
	OPT_i = 1 << OPTBIT_i,
	OPT_H = 1 << OPTBIT_H,
	OPT_h = 1 << OPTBIT_h,
	OPT_e = 1 << OPTBIT_e,
	OPT_f = 1 << OPTBIT_f,
	OPT_L = 1 << OPTBIT_L,
	OPT_o = 1 << OPTBIT_o,
	OPT_r = 1 << OPTBIT_r,
	OPT_m = 1 << OPTBIT_m,
	OPT_w = 1 << OPTBIT_w,
	OPT_A = IF_FEATURE_GREP_CONTEXT(    (1 << OPTBIT_A)) + 0,
	OPT_B = IF_FEATURE_GREP_CONTEXT(    (1 << OPTBIT_B)) + 0,
	OPT_C = IF_FEATURE_GREP_CONTEXT(    (1 << OPTBIT_C)) + 0,
	OPT_E = IF_FEATURE_GREP_EGREP_ALIAS((1 << OPTBIT_E)) + 0,
	OPT_z = IF_EXTRA_COMPAT(            (1 << OPTBIT_z)) + 0,
};

#define PRINT_FILES_WITH_MATCHES    (option_mask32 & OPT_l)
#define PRINT_LINE_NUM              (option_mask32 & OPT_n)
#define BE_QUIET                    (option_mask32 & OPT_q)
#define SUPPRESS_ERR_MSGS           (option_mask32 & OPT_s)
#define PRINT_MATCH_COUNTS          (option_mask32 & OPT_c)
#define FGREP_FLAG                  (option_mask32 & OPT_F)
#define PRINT_FILES_WITHOUT_MATCHES (option_mask32 & OPT_L)
#define NUL_DELIMITED               (option_mask32 & OPT_z)

struct globals {
	int max_matches;
#if !ENABLE_EXTRA_COMPAT
	int reflags;
#else
	RE_TRANSLATE_TYPE case_fold; /* RE_TRANSLATE_TYPE is [[un]signed] char* */
#endif
	smalluint invert_search;
	smalluint print_filename;
	smalluint open_errors;
#if ENABLE_FEATURE_GREP_CONTEXT
	smalluint did_print_line;
	int lines_before;
	int lines_after;
	char **before_buf;
	IF_EXTRA_COMPAT(size_t *before_buf_size;)
	int last_line_printed;
#endif
	/* globals used internally */
	llist_t *pattern_head;   /* growable list of patterns to match */
	const char *cur_file;    /* the current file we are reading */
} FIX_ALIASING;
#define G (*(struct globals*)&bb_common_bufsiz1)
#define INIT_G() do { \
	struct G_sizecheck { \
		char G_sizecheck[sizeof(G) > COMMON_BUFSIZE ? -1 : 1]; \
	}; \
} while (0)
#define max_matches       (G.max_matches         )
#if !ENABLE_EXTRA_COMPAT
# define reflags          (G.reflags             )
#else
# define case_fold        (G.case_fold           )
/* http://www.delorie.com/gnu/docs/regex/regex_46.html */
# define reflags           re_syntax_options
# undef REG_NOSUB
# undef REG_EXTENDED
# undef REG_ICASE
# define REG_NOSUB    bug:is:here /* should not be used */
/* Just RE_SYNTAX_EGREP is not enough, need to enable {n[,[m]]} too */
# define REG_EXTENDED (RE_SYNTAX_EGREP | RE_INTERVALS | RE_NO_BK_BRACES)
# define REG_ICASE    bug:is:here /* should not be used */
#endif
#define invert_search     (G.invert_search       )
#define print_filename    (G.print_filename      )
#define open_errors       (G.open_errors         )
#define did_print_line    (G.did_print_line      )
#define lines_before      (G.lines_before        )
#define lines_after       (G.lines_after         )
#define before_buf        (G.before_buf          )
#define before_buf_size   (G.before_buf_size     )
#define last_line_printed (G.last_line_printed   )
#define pattern_head      (G.pattern_head        )
#define cur_file          (G.cur_file            )


typedef struct grep_list_data_t {
	char *pattern;
/* for GNU regex, matched_range must be persistent across grep_file() calls */
#if !ENABLE_EXTRA_COMPAT
	regex_t compiled_regex;
	regmatch_t matched_range;
#else
	struct re_pattern_buffer compiled_regex;
	struct re_registers matched_range;
#endif
#define ALLOCATED 1
#define COMPILED 2
	int flg_mem_alocated_compiled;
} grep_list_data_t;

#if !ENABLE_EXTRA_COMPAT
#define print_line(line, line_len, linenum, decoration) \
	print_line(line, linenum, decoration)
#endif
static void print_line(const char *line, size_t line_len, int linenum, char decoration)
{
#if ENABLE_FEATURE_GREP_CONTEXT
	/* Happens when we go to next file, immediately hit match
	 * and try to print prev context... from prev file! Don't do it */
	if (linenum < 1)
		return;
	/* possibly print the little '--' separator */
	if ((lines_before || lines_after) && did_print_line
	 && last_line_printed != linenum - 1
	) {
		puts("--");
	}
	/* guard against printing "--" before first line of first file */
	did_print_line = 1;
	last_line_printed = linenum;
#endif
	if (print_filename)
		printf("%s%c", cur_file, decoration);
	if (PRINT_LINE_NUM)
		printf("%i%c", linenum, decoration);
	/* Emulate weird GNU grep behavior with -ov */
	if ((option_mask32 & (OPT_v|OPT_o)) != (OPT_v|OPT_o)) {
#if !ENABLE_EXTRA_COMPAT
		puts(line);
#else
		fwrite(line, 1, line_len, stdout);
		putchar(NUL_DELIMITED ? '\0' : '\n');
#endif
	}
}

#if ENABLE_EXTRA_COMPAT
/* Unlike getline, this one removes trailing '\n' */
static ssize_t FAST_FUNC bb_getline(char **line_ptr, size_t *line_alloc_len, FILE *file)
{
	ssize_t res_sz;
	char *line;
	int delim = (NUL_DELIMITED ? '\0' : '\n');

	res_sz = getdelim(line_ptr, line_alloc_len, delim, file);
	line = *line_ptr;

	if (res_sz > 0) {
		if (line[res_sz - 1] == delim)
			line[--res_sz] = '\0';
	} else {
		free(line); /* uclibc allocates a buffer even on EOF. WTF? */
	}
	return res_sz;
}
#endif

static int grep_file(FILE *file)
{
	smalluint found;
	int linenum = 0;
	int nmatches = 0;
#if !ENABLE_EXTRA_COMPAT
	char *line;
#else
	char *line = NULL;
	ssize_t line_len;
	size_t line_alloc_len;
# define rm_so start[0]
# define rm_eo end[0]
#endif
#if ENABLE_FEATURE_GREP_CONTEXT
	int print_n_lines_after = 0;
	int curpos = 0; /* track where we are in the circular 'before' buffer */
	int idx = 0; /* used for iteration through the circular buffer */
#else
	enum { print_n_lines_after = 0 };
#endif

	while (
#if !ENABLE_EXTRA_COMPAT
		(line = xmalloc_fgetline(file)) != NULL
#else
		(line_len = bb_getline(&line, &line_alloc_len, file)) >= 0
#endif
	) {
		llist_t *pattern_ptr = pattern_head;
		grep_list_data_t *gl = gl; /* for gcc */

		linenum++;
		found = 0;
		while (pattern_ptr) {
			gl = (grep_list_data_t *)pattern_ptr->data;
			if (FGREP_FLAG) {
				found |= (((option_mask32 & OPT_i)
					? strcasestr(line, gl->pattern)
					: strstr(line, gl->pattern)
					) != NULL);
			} else {
				if (!(gl->flg_mem_alocated_compiled & COMPILED)) {
					gl->flg_mem_alocated_compiled |= COMPILED;
#if !ENABLE_EXTRA_COMPAT
					xregcomp(&gl->compiled_regex, gl->pattern, reflags);
#else
					memset(&gl->compiled_regex, 0, sizeof(gl->compiled_regex));
					gl->compiled_regex.translate = case_fold; /* for -i */
					if (re_compile_pattern(gl->pattern, strlen(gl->pattern), &gl->compiled_regex))
						bb_error_msg_and_die("bad regex '%s'", gl->pattern);
#endif
				}
#if !ENABLE_EXTRA_COMPAT
				gl->matched_range.rm_so = 0;
				gl->matched_range.rm_eo = 0;
#endif
				if (
#if !ENABLE_EXTRA_COMPAT
					regexec(&gl->compiled_regex, line, 1, &gl->matched_range, 0) == 0
#else
					re_search(&gl->compiled_regex, line, line_len,
							/*start:*/ 0, /*range:*/ line_len,
							&gl->matched_range) >= 0
#endif
				) {
					if (!(option_mask32 & OPT_w))
						found = 1;
					else {
						char c = ' ';
						if (gl->matched_range.rm_so)
							c = line[gl->matched_range.rm_so - 1];
						if (!isalnum(c) && c != '_') {
							c = line[gl->matched_range.rm_eo];
							if (!c || (!isalnum(c) && c != '_'))
								found = 1;
						}
					}
				}
			}
			/* If it's non-inverted search, we can stop
			 * at first match */
			if (found && !invert_search)
				goto do_found;
			pattern_ptr = pattern_ptr->link;
		} /* while (pattern_ptr) */

		if (found ^ invert_search) {
 do_found:
			/* keep track of matches */
			nmatches++;

			/* quiet/print (non)matching file names only? */
			if (option_mask32 & (OPT_q|OPT_l|OPT_L)) {
				free(line); /* we don't need line anymore */
				if (BE_QUIET) {
					/* manpage says about -q:
					 * "exit immediately with zero status
					 * if any match is found,
					 * even if errors were detected" */
					exit(EXIT_SUCCESS);
				}
				/* if we're just printing filenames, we stop after the first match */
				if (PRINT_FILES_WITH_MATCHES) {
					puts(cur_file);
					/* fall through to "return 1" */
				}
				/* OPT_L aka PRINT_FILES_WITHOUT_MATCHES: return early */
				return 1; /* one match */
			}

#if ENABLE_FEATURE_GREP_CONTEXT
			/* Were we printing context and saw next (unwanted) match? */
			if ((option_mask32 & OPT_m) && nmatches > max_matches)
				break;
#endif

			/* print the matched line */
			if (PRINT_MATCH_COUNTS == 0) {
#if ENABLE_FEATURE_GREP_CONTEXT
				int prevpos = (curpos == 0) ? lines_before - 1 : curpos - 1;

				/* if we were told to print 'before' lines and there is at least
				 * one line in the circular buffer, print them */
				if (lines_before && before_buf[prevpos] != NULL) {
					int first_buf_entry_line_num = linenum - lines_before;

					/* advance to the first entry in the circular buffer, and
					 * figure out the line number is of the first line in the
					 * buffer */
					idx = curpos;
					while (before_buf[idx] == NULL) {
						idx = (idx + 1) % lines_before;
						first_buf_entry_line_num++;
					}

					/* now print each line in the buffer, clearing them as we go */
					while (before_buf[idx] != NULL) {
						print_line(before_buf[idx], before_buf_size[idx], first_buf_entry_line_num, '-');
						free(before_buf[idx]);
						before_buf[idx] = NULL;
						idx = (idx + 1) % lines_before;
						first_buf_entry_line_num++;
					}
				}

				/* make a note that we need to print 'after' lines */
				print_n_lines_after = lines_after;
#endif
				if (option_mask32 & OPT_o) {
					if (FGREP_FLAG) {
						/* -Fo just prints the pattern
						 * (unless -v: -Fov doesnt print anything at all) */
						if (found)
							print_line(gl->pattern, strlen(gl->pattern), linenum, ':');
					} else while (1) {
						unsigned end = gl->matched_range.rm_eo;
						char old = line[end];
						line[end] = '\0';
						print_line(line + gl->matched_range.rm_so,
								end - gl->matched_range.rm_so,
								linenum, ':');
						if (old == '\0')
							break;
						line[end] = old;
#if !ENABLE_EXTRA_COMPAT
						if (regexec(&gl->compiled_regex, line + end,
								1, &gl->matched_range, REG_NOTBOL) != 0)
							break;
						gl->matched_range.rm_so += end;
						gl->matched_range.rm_eo += end;
#else
						if (re_search(&gl->compiled_regex, line, line_len,
								end, line_len - end,
								&gl->matched_range) < 0)
							break;
#endif
					}
				} else {
					print_line(line, line_len, linenum, ':');
				}
			}
		}
#if ENABLE_FEATURE_GREP_CONTEXT
		else { /* no match */
			/* if we need to print some context lines after the last match, do so */
			if (print_n_lines_after) {
				print_line(line, strlen(line), linenum, '-');
				print_n_lines_after--;
			} else if (lines_before) {
				/* Add the line to the circular 'before' buffer */
				free(before_buf[curpos]);
				before_buf[curpos] = line;
				IF_EXTRA_COMPAT(before_buf_size[curpos] = line_len;)
				curpos = (curpos + 1) % lines_before;
				/* avoid free(line) - we took the line */
				line = NULL;
			}
		}

#endif /* ENABLE_FEATURE_GREP_CONTEXT */
#if !ENABLE_EXTRA_COMPAT
		free(line);
#endif
		/* Did we print all context after last requested match? */
		if ((option_mask32 & OPT_m)
		 && !print_n_lines_after
		 && nmatches == max_matches
		) {
			break;
		}
	} /* while (read line) */

	/* special-case file post-processing for options where we don't print line
	 * matches, just filenames and possibly match counts */

	/* grep -c: print [filename:]count, even if count is zero */
	if (PRINT_MATCH_COUNTS) {
		if (print_filename)
			printf("%s:", cur_file);
		printf("%d\n", nmatches);
	}

	/* grep -L: print just the filename */
	if (PRINT_FILES_WITHOUT_MATCHES) {
		/* nmatches is zero, no need to check it:
		 * we return 1 early if we detected a match
		 * and PRINT_FILES_WITHOUT_MATCHES is set */
		puts(cur_file);
	}

	return nmatches;
}

#if ENABLE_FEATURE_CLEAN_UP
#define new_grep_list_data(p, m) add_grep_list_data(p, m)
static char *add_grep_list_data(char *pattern, int flg_used_mem)
#else
#define new_grep_list_data(p, m) add_grep_list_data(p)
static char *add_grep_list_data(char *pattern)
#endif
{
	grep_list_data_t *gl = xzalloc(sizeof(*gl));
	gl->pattern = pattern;
#if ENABLE_FEATURE_CLEAN_UP
	gl->flg_mem_alocated_compiled = flg_used_mem;
#else
	/*gl->flg_mem_alocated_compiled = 0;*/
#endif
	return (char *)gl;
}

static void load_regexes_from_file(llist_t *fopt)
{
	char *line;
	FILE *f;

	while (fopt) {
		llist_t *cur = fopt;
		char *ffile = cur->data;

		fopt = cur->link;
		free(cur);
		f = xfopen_stdin(ffile);
		while ((line = xmalloc_fgetline(f)) != NULL) {
			llist_add_to(&pattern_head,
				new_grep_list_data(line, ALLOCATED));
		}
	}
}

static int FAST_FUNC file_action_grep(const char *filename,
			struct stat *statbuf UNUSED_PARAM,
			void* matched,
			int depth UNUSED_PARAM)
{
	FILE *file = fopen_for_read(filename);
	if (file == NULL) {
		if (!SUPPRESS_ERR_MSGS)
			bb_simple_perror_msg(filename);
		open_errors = 1;
		return 0;
	}
	cur_file = filename;
	*(int*)matched += grep_file(file);
	fclose(file);
	return 1;
}

static int grep_dir(const char *dir)
{
	int matched = 0;
	recursive_action(dir,
		/* recurse=yes */ ACTION_RECURSE |
		/* followLinks=no */
		/* depthFirst=yes */ ACTION_DEPTHFIRST,
		/* fileAction= */ file_action_grep,
		/* dirAction= */ NULL,
		/* userData= */ &matched,
		/* depth= */ 0);
	return matched;
}

int grep_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int grep_main(int argc UNUSED_PARAM, char **argv)
{
	FILE *file;
	int matched;
	llist_t *fopt = NULL;

	/* do normal option parsing */
#if ENABLE_FEATURE_GREP_CONTEXT
	int Copt;

	/* -H unsets -h; -C unsets -A,-B; -e,-f are lists;
	 * -m,-A,-B,-C have numeric param */
	opt_complementary = "H-h:C-AB:e::f::m+:A+:B+:C+";
	getopt32(argv,
		OPTSTR_GREP,
		&pattern_head, &fopt, &max_matches,
		&lines_after, &lines_before, &Copt);

	if (option_mask32 & OPT_C) {
		/* -C unsets prev -A and -B, but following -A or -B
		   may override it */
		if (!(option_mask32 & OPT_A)) /* not overridden */
			lines_after = Copt;
		if (!(option_mask32 & OPT_B)) /* not overridden */
			lines_before = Copt;
	}
	/* sanity checks */
	if (option_mask32 & (OPT_c|OPT_q|OPT_l|OPT_L)) {
		option_mask32 &= ~OPT_n;
		lines_before = 0;
		lines_after = 0;
	} else if (lines_before > 0) {
		before_buf = xzalloc(lines_before * sizeof(before_buf[0]));
		IF_EXTRA_COMPAT(before_buf_size = xzalloc(lines_before * sizeof(before_buf_size[0]));)
	}
#else
	/* with auto sanity checks */
	/* -H unsets -h; -c,-q or -l unset -n; -e,-f are lists; -m N */
	opt_complementary = "H-h:c-n:q-n:l-n:e::f::m+";
	getopt32(argv, OPTSTR_GREP,
		&pattern_head, &fopt, &max_matches);
#endif
	invert_search = ((option_mask32 & OPT_v) != 0); /* 0 | 1 */

	if (pattern_head != NULL) {
		/* convert char **argv to grep_list_data_t */
		llist_t *cur;

		for (cur = pattern_head; cur; cur = cur->link)
			cur->data = new_grep_list_data(cur->data, 0);
	}
	if (option_mask32 & OPT_f)
		load_regexes_from_file(fopt);

	if (ENABLE_FEATURE_GREP_FGREP_ALIAS && applet_name[0] == 'f')
		option_mask32 |= OPT_F;

#if !ENABLE_EXTRA_COMPAT
	if (!(option_mask32 & (OPT_o | OPT_w)))
		reflags = REG_NOSUB;
#endif

	if (ENABLE_FEATURE_GREP_EGREP_ALIAS
	 && (applet_name[0] == 'e' || (option_mask32 & OPT_E))
	) {
		reflags |= REG_EXTENDED;
	}
#if ENABLE_EXTRA_COMPAT
	else {
		reflags = RE_SYNTAX_GREP;
	}
#endif

	if (option_mask32 & OPT_i) {
#if !ENABLE_EXTRA_COMPAT
		reflags |= REG_ICASE;
#else
		int i;
		case_fold = xmalloc(256);
		for (i = 0; i < 256; i++)
			case_fold[i] = (unsigned char)i;
		for (i = 'a'; i <= 'z'; i++)
			case_fold[i] = (unsigned char)(i - ('a' - 'A'));
#endif
	}

	argv += optind;

	/* if we didn't get a pattern from -e and no command file was specified,
	 * first parameter should be the pattern. no pattern, no worky */
	if (pattern_head == NULL) {
		char *pattern;
		if (*argv == NULL)
			bb_show_usage();
		pattern = new_grep_list_data(*argv++, 0);
		llist_add_to(&pattern_head, pattern);
	}

	/* argv[0..(argc-1)] should be names of file to grep through. If
	 * there is more than one file to grep, we will print the filenames. */
	if (argv[0] && argv[1])
		print_filename = 1;
	/* -H / -h of course override */
	if (option_mask32 & OPT_H)
		print_filename = 1;
	if (option_mask32 & OPT_h)
		print_filename = 0;

	/* If no files were specified, or '-' was specified, take input from
	 * stdin. Otherwise, we grep through all the files specified. */
	matched = 0;
	do {
		cur_file = *argv;
		file = stdin;
		if (!cur_file || LONE_DASH(cur_file)) {
			cur_file = "(standard input)";
		} else {
			if (option_mask32 & OPT_r) {
				struct stat st;
				if (stat(cur_file, &st) == 0 && S_ISDIR(st.st_mode)) {
					if (!(option_mask32 & OPT_h))
						print_filename = 1;
					matched += grep_dir(cur_file);
					goto grep_done;
				}
			}
			/* else: fopen(dir) will succeed, but reading won't */
			file = fopen_for_read(cur_file);
			if (file == NULL) {
				if (!SUPPRESS_ERR_MSGS)
					bb_simple_perror_msg(cur_file);
				open_errors = 1;
				continue;
			}
		}
		matched += grep_file(file);
		fclose_if_not_stdin(file);
 grep_done: ;
	} while (*argv && *++argv);

	/* destroy all the elments in the pattern list */
	if (ENABLE_FEATURE_CLEAN_UP) {
		while (pattern_head) {
			llist_t *pattern_head_ptr = pattern_head;
			grep_list_data_t *gl = (grep_list_data_t *)pattern_head_ptr->data;

			pattern_head = pattern_head->link;
			if (gl->flg_mem_alocated_compiled & ALLOCATED)
				free(gl->pattern);
			if (gl->flg_mem_alocated_compiled & COMPILED)
				regfree(&gl->compiled_regex);
			free(gl);
			free(pattern_head_ptr);
		}
	}
	/* 0 = success, 1 = failed, 2 = error */
	if (open_errors)
		return 2;
	return !matched; /* invert return value: 0 = success, 1 = failed */
}