busybox/grep.c

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/*
* Mini grep implementation for busybox using libc regex.
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*
* 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
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*
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h> /* for getopt() */
#include <regex.h>
#include <string.h> /* for strerror() */
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#include <errno.h>
#include "internal.h"
extern int optind; /* in unistd.h */
extern int errno; /* for use with strerror() */
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static const char grep_usage[] =
"grep [-ihHnqvs] pattern [files...]\n"
#ifndef BB_FEATURE_TRIVIAL_HELP
"\nSearch for PATTERN in each FILE or standard input.\n\n"
"Options:\n"
"\t-H\tprefix output lines with filename where match was found\n"
"\t-h\tsuppress the prefixing filename on output\n"
"\t-i\tignore case distinctions\n"
"\t-n\tprint line number with output lines\n"
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"\t-q\tbe quiet. Returns 0 if result was found, 1 otherwise\n"
"\t-v\tselect non-matching lines\n"
"\t-s\tsuppress file open/read error messages\n\n"
#endif
;
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/* options */
static int ignore_case = 0;
static int print_filename = 0;
static int print_line_num = 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 nmatches = 0; /* keeps track of the number of matches */
static char *cur_file = NULL; /* the current file we are reading */
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static void print_matched_line(char *line, int linenum)
{
if (print_filename)
printf("%s:", cur_file);
if (print_line_num)
printf("%i:", linenum);
printf("%s", line);
}
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static void grep_file(FILE *file)
{
char *line = NULL;
int ret;
int linenum = 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);
}
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nmatches++;
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print_matched_line(line, linenum);
} else if (ret == REG_NOMATCH && invert_search) {
print_matched_line(line, linenum);
}
free(line);
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}
}
extern int grep_main(int argc, char **argv)
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{
int opt;
int reflags;
int ret;
/* do special-case option parsing */
if (argv[1] && (strcmp(argv[1], "--help") == 0))
usage(grep_usage);
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/* do normal option parsing */
while ((opt = getopt(argc, argv, "iHhnqvs")) > 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;
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case 'v':
invert_search++;
break;
case 's':
suppress_err_msgs++;
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break;
}
}
/* argv[optind] should be the regex pattern; no pattern, no worky */
if (argv[optind] == NULL)
usage(grep_usage);
/* compile the regular expression */
reflags = REG_NOSUB; /* we're not going to mess with sub-expressions */
if (ignore_case)
reflags |= REG_ICASE;
if ((ret = regcomp(&regex, argv[optind], reflags)) != 0) {
int errmsgsz = regerror(ret, &regex, NULL, 0);
char *errmsg = malloc(errmsgsz);
if (errmsg == NULL) {
fprintf(stderr, "grep: memory error\n");
regfree(&regex);
exit(1);
}
regerror(ret, &regex, errmsg, errmsgsz);
fprintf(stderr, "grep: %s\n", errmsg);
free(errmsg);
regfree(&regex);
exit(1);
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}
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/* 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++;
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/* 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)
fprintf(stderr, "grep: %s: %s\n", cur_file, strerror(errno));
} else {
grep_file(file);
fclose(file);
}
}
}
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regfree(&regex);
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if (nmatches == 0)
return 1;
return 0;
}