summaryrefslogtreecommitdiff
path: root/findutils/grep.c
blob: 003dae98ed92a03fa5b76e8240aba84bffbf0260 (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
/*
 * Mini grep implementation for busybox using libc regex.
 *
 * Copyright (C) 1999,2000 by Lineo, inc.
 * Written by Mark Whitley <markw@lineo.com>, <markw@enol.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <getopt.h>
#include <regex.h>
#include <string.h> /* for strerror() */
#include <errno.h>
#include "busybox.h"

extern int optind; /* in unistd.h */
extern int errno;  /* for use with strerror() */

/* options */
static int ignore_case       = 0;
static int print_filename    = 0;
static int print_line_num    = 0;
static int print_count_only  = 0;
static int be_quiet          = 0;
static int invert_search     = 0;
static int suppress_err_msgs = 0;

/* globals */
static regex_t regex; /* storage space for compiled regular expression */
static int matched; /* keeps track of whether we ever matched */
static char *cur_file = NULL; /* the current file we are reading */


static void print_matched_line(char *line, int linenum)
{
	if (print_count_only)
		return;

	if (print_filename)
		printf("%s:", cur_file);
	if (print_line_num)
		printf("%i:", linenum);

	printf("%s", line);
}

static void grep_file(FILE *file)
{
	char *line = NULL;
	int ret;
	int linenum = 0;
	int nmatches = 0;

	while ((line = get_line_from_file(file)) != NULL) {
		linenum++;
		ret = regexec(&regex, line, 0, NULL, 0);
		if (ret == 0 && !invert_search) { /* match */

			/* if we found a match but were told to be quiet, stop here and
			 * return success */
			if (be_quiet) {
				regfree(&regex);
				exit(0);
			}

			nmatches++;
			print_matched_line(line, linenum);

		}
		else if (ret == REG_NOMATCH && invert_search) {
			nmatches++;
			print_matched_line(line, linenum);
		}

		free(line);
	}

	/* special-case post processing */
	if (print_count_only) {
		if (print_filename)
			printf("%s:", cur_file);
		printf("%i\n", nmatches);
	}

	/* record if we matched */
	if (nmatches != 0)
		matched = 1;
}

extern int grep_main(int argc, char **argv)
{
	int opt;
	int reflags;

	/* do normal option parsing */
	while ((opt = getopt(argc, argv, "iHhnqvsc")) > 0) {
		switch (opt) {
			case 'i':
				ignore_case++;
				break;
			case 'H':
				print_filename++;
				break;
			case 'h':
				print_filename--;
				break;
			case 'n':
				print_line_num++;
				break;
			case 'q':
				be_quiet++;
				break;
			case 'v':
				invert_search++;
				break;
			case 's':
				suppress_err_msgs++;
				break;
			case 'c':
				print_count_only++;
				break;
		}
	}

	/* argv[optind] should be the regex pattern; no pattern, no worky */
	if (argv[optind] == NULL)
		usage(grep_usage);

	/* compile the regular expression
	 * we're not going to mess with sub-expressions, and we need to
	 * treat newlines right. */
	reflags = REG_NOSUB | REG_NEWLINE; 
	if (ignore_case)
		reflags |= REG_ICASE;
	xregcomp(&regex, argv[optind], reflags);

	/* argv[(optind+1)..(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 ((argc-1) - (optind+1) > 0)
		print_filename++;

	/* If no files were specified, or '-' was specified, take input from
	 * stdin. Otherwise, we grep through all the files specified. */
	if (argv[optind+1] == NULL || (strcmp(argv[optind+1], "-") == 0)) {
		grep_file(stdin);
	}
	else {
		int i;
		FILE *file;
		for (i = optind + 1; i < argc; i++) {
			cur_file = argv[i];
			file = fopen(cur_file, "r");
			if (file == NULL) {
				if (!suppress_err_msgs)
					errorMsg("%s: %s\n", cur_file, strerror(errno));
			}
			else {
				grep_file(file);
				fclose(file);
			}
		}
	}

	regfree(&regex);

	if (!matched)
		return 1;

	return 0;
}