busybox/grep.c

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/*
* Mini grep implementation for busybox using libc regex.
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*
* 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
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*
*/
#include <stdio.h>
#include <stdlib.h>
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#include <getopt.h>
#include <regex.h>
#include <string.h> /* for strerror() */
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#include <errno.h>
#include "busybox.h"
extern int optind; /* in unistd.h */
extern int errno; /* for use with strerror() */
extern void xregcomp(regex_t *preg, const char *regex, int cflags); /* in busybox.h */
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/* 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;
#ifdef BB_FEATURE_GREP_CONTEXT
extern char *optarg; /* in getopt.h */
static int lines_before = 0;
static int lines_after = 0;
static char **before_buf = NULL;
static int last_line_printed = 0;
#endif /* BB_FEATURE_GREP_CONTEXT */
/* globals used internally */
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_line(const char *line, int linenum, char decoration)
{
#ifdef BB_FEATURE_GREP_CONTEXT
/* possibly print the little '--' seperator */
if (last_line_printed && last_line_printed < linenum - 1) {
puts("--");
}
last_line_printed = linenum;
#endif
if (print_filename)
printf("%s%c", cur_file, decoration);
if (print_line_num)
printf("%i%c", linenum, decoration);
puts(line);
}
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static void grep_file(FILE *file)
{
char *line = NULL;
int ret;
int linenum = 0;
int nmatches = 0;
#ifdef BB_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 */
#endif /* BB_FEATURE_GREP_CONTEXT */
while ((line = get_line_from_file(file)) != NULL) {
chomp(line);
linenum++;
/*
* test for a postitive-assertion match (regexec returns success (0)
* and the user did not specify invert search), or a negative-assertion
* match (regexec returns failure (REG_NOMATCH) and the user specified
* invert search)
*/
ret = regexec(&regex, line, 0, NULL, 0);
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);
}
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/* otherwise, keep track of matches and print the matched line */
nmatches++;
if (!print_count_only) {
#ifdef BB_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], 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 /* BB_FEATURE_GREP_CONTEXT */
print_line(line, linenum, ':');
}
}
#ifdef BB_FEATURE_GREP_CONTEXT
else { /* no match */
/* Add the line to the circular 'before' buffer */
if(lines_before)
{
if(before_buf[curpos])
free(before_buf[curpos]);
before_buf[curpos] = strdup(line);
curpos = (curpos + 1) % lines_before;
}
}
/* if we need to print some context lines after the last match, do so */
if (print_n_lines_after && (last_line_printed != linenum)) {
print_line(line, linenum, '-');
print_n_lines_after--;
}
#endif /* BB_FEATURE_GREP_CONTEXT */
free(line);
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}
/* special-case post processing */
if (print_count_only) {
if (print_filename)
printf("%s:", cur_file);
printf("%i\n", nmatches);
}
/* remember if we matched */
if (nmatches != 0)
matched = 1;
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}
extern int grep_main(int argc, char **argv)
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{
int opt;
int reflags;
#ifdef BB_FEATURE_GREP_CONTEXT
char *junk;
#endif
/* do normal option parsing */
while ((opt = getopt(argc, argv, "iHhnqvsc"
#ifdef BB_FEATURE_GREP_CONTEXT
"A:B:C:"
#endif
)) > 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;
case 'c':
print_count_only++;
break;
#ifdef BB_FEATURE_GREP_CONTEXT
case 'A':
lines_after = strtoul(optarg, &junk, 10);
if(*junk != '\0')
error_msg_and_die("invalid context length argument");
break;
case 'B':
lines_before = strtoul(optarg, &junk, 10);
if(*junk != '\0')
error_msg_and_die("invalid context length argument");
before_buf = (char **)calloc(lines_before, sizeof(char *));
break;
case 'C':
lines_after = lines_before = strtoul(optarg, &junk, 10);
if(*junk != '\0')
error_msg_and_die("invalid context length argument");
before_buf = (char **)calloc(lines_before, sizeof(char *));
break;
#endif /* BB_FEATURE_GREP_CONTEXT */
}
}
/* argv[optind] should be the regex pattern; no pattern, no worky */
if (argv[optind] == NULL)
usage(grep_usage);
/* sanity check */
if (print_count_only || be_quiet) {
print_line_num = 0;
#ifdef BB_FEATURE_GREP_CONTEXT
lines_before = 0;
lines_after = 0;
#endif
}
/* 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);
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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)
perror_msg("%s", cur_file);
}
else {
grep_file(file);
fclose(file);
}
}
}
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regfree(&regex);
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return !matched; /* invert return value 0 = success, 1 = failed */
}