busybox/grep.c

179 lines
4.4 KiB
C

/*
* Mini grep implementation for busybox using libc regex.
*
* Copyright (C) 1999,2000,2001 by Lineo, inc.
* Written by Mark Whitley <markw@lineo.com>, <markw@codepoet.org>
*
* 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 void xregcomp(regex_t *preg, const char *regex, int cflags);
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 grep_file(FILE *file)
{
char *line = NULL;
int ret;
int linenum = 0;
int nmatches = 0;
while ((line = get_line_from_file(file)) != NULL) {
chomp(line);
linenum++;
ret = regexec(&regex, line, 0, NULL, 0);
/* test for a postitive-assertion match (regexec returned success (0)
* and the user did not specify invert search), or a negative-assertion
* match (vice versa) */
if ((ret == 0 && !invert_search) || (ret == REG_NOMATCH && invert_search)) {
/* if we found a match but were told to be quiet, stop here and
* return success */
if (be_quiet) {
regfree(&regex);
exit(0);
}
/* otherwise, keep track of matches, print the matched line, and
* whatever else the user wanted */
nmatches++;
if (!print_count_only) {
if (print_filename)
printf("%s:", cur_file);
if (print_line_num)
printf("%i:", linenum);
puts(line);
}
}
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;
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)
perror_msg("%s", cur_file);
}
else {
grep_file(file);
fclose(file);
}
}
}
regfree(&regex);
return !matched; /* invert return value 0 = success, 1 = failed */
}