372 lines
		
	
	
		
			9.6 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			372 lines
		
	
	
		
			9.6 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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 * Mini grep implementation for busybox using libc regex.
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 *
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 * Copyright (C) 1999,2000,2001 by Lineo, inc. and Mark Whitley
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 * Copyright (C) 1999,2000,2001 by Mark Whitley <markw@codepoet.org> 
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 *
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 * This program is free software; you can redistribute it and/or modify
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 * it under the terms of the GNU General Public License as published by
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 * the Free Software Foundation; either version 2 of the License, or
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 * (at your option) any later version.
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 *
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 * This program is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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 * General Public License for more details.
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 *
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 * You should have received a copy of the GNU General Public License
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 * along with this program; if not, write to the Free Software
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 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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 *
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 */
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#include <stdio.h>
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#include <stdlib.h>
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#include <getopt.h>
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#include <regex.h>
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#include <string.h> /* for strerror() */
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#include <errno.h>
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#include "busybox.h"
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extern int optind; /* in unistd.h */
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extern void xregcomp(regex_t *preg, const char *regex, int cflags); /* in busybox.h */
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/* options */
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static int reflags            = REG_NOSUB; 
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static int print_filename     = 0;
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static int print_line_num     = 0;
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static int print_match_counts = 0;
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static int be_quiet           = 0;
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static int invert_search      = 0;
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static int suppress_err_msgs  = 0;
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static int print_files_with_matches  = 0;
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#ifdef CONFIG_FEATURE_GREP_CONTEXT
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extern char *optarg; /* in getopt.h */
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static int lines_before      = 0;
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static int lines_after       = 0;
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static char **before_buf     = NULL;
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static int last_line_printed = 0;
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#endif /* CONFIG_FEATURE_GREP_CONTEXT */
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/* globals used internally */
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static regex_t *regexes = NULL; /* growable array of compiled regular expressions */
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static int nregexes = 0; /* number of elements in above arrary */
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static int matched; /* keeps track of whether we ever matched */
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static char *cur_file = NULL; /* the current file we are reading */
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static void print_line(const char *line, int linenum, char decoration)
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{
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#ifdef CONFIG_FEATURE_GREP_CONTEXT
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	/* possibly print the little '--' seperator */
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	if ((lines_before || lines_after) && last_line_printed &&
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			last_line_printed < linenum - 1) {
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		puts("--");
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	}
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	last_line_printed = linenum;
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#endif
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	if (print_filename)
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		printf("%s%c", cur_file, decoration);
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	if (print_line_num)
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		printf("%i%c", linenum, decoration);
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	puts(line);
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}
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static void grep_file(FILE *file)
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{
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	char *line = NULL;
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	int ret;
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	int linenum = 0;
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	int nmatches = 0;
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	int i;
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#ifdef CONFIG_FEATURE_GREP_CONTEXT
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	int print_n_lines_after = 0;
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	int curpos = 0; /* track where we are in the circular 'before' buffer */
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	int idx = 0; /* used for iteration through the circular buffer */
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#endif /* CONFIG_FEATURE_GREP_CONTEXT */ 
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	while ((line = get_line_from_file(file)) != NULL) {
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		chomp(line);
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		linenum++;
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		for (i = 0; i < nregexes; i++) {
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			/*
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			 * test for a postitive-assertion match (regexec returns success (0)
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			 * and the user did not specify invert search), or a negative-assertion
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			 * match (regexec returns failure (REG_NOMATCH) and the user specified
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			 * invert search)
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			 */
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			ret = regexec(®exes[i], line, 0, NULL, 0);
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			if ((ret == 0 && !invert_search) || (ret == REG_NOMATCH && invert_search)) {
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				/* if we found a match but were told to be quiet, stop here and
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				 * return success */
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				if (be_quiet)
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					exit(0);
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				/* keep track of matches */
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				nmatches++;
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				/* if we're just printing filenames, we stop after the first match */
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				if (print_files_with_matches)
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					break;
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				/* print the matched line */
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				if (print_match_counts == 0) {
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#ifdef CONFIG_FEATURE_GREP_CONTEXT
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					int prevpos = (curpos == 0) ? lines_before - 1 : curpos - 1;
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					/* if we were told to print 'before' lines and there is at least
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					 * one line in the circular buffer, print them */
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					if (lines_before && before_buf[prevpos] != NULL) {
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						int first_buf_entry_line_num = linenum - lines_before;
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						/* advance to the first entry in the circular buffer, and
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						 * figure out the line number is of the first line in the
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						 * buffer */
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						idx = curpos;
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						while (before_buf[idx] == NULL) {
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							idx = (idx + 1) % lines_before;
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							first_buf_entry_line_num++;
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						}
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						/* now print each line in the buffer, clearing them as we go */
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						while (before_buf[idx] != NULL) {
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							print_line(before_buf[idx], first_buf_entry_line_num, '-');
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							free(before_buf[idx]);
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							before_buf[idx] = NULL;
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							idx = (idx + 1) % lines_before;
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							first_buf_entry_line_num++;
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						}
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					}
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					/* make a note that we need to print 'after' lines */
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					print_n_lines_after = lines_after;
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#endif /* CONFIG_FEATURE_GREP_CONTEXT */ 
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					print_line(line, linenum, ':');
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				}
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			}
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#ifdef CONFIG_FEATURE_GREP_CONTEXT
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			else { /* no match */
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				/* Add the line to the circular 'before' buffer */
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				if(lines_before) {
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					if(before_buf[curpos])
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						free(before_buf[curpos]);
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					before_buf[curpos] = xstrdup(line);
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					curpos = (curpos + 1) % lines_before;
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				}
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			}
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			/* if we need to print some context lines after the last match, do so */
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			if (print_n_lines_after && (last_line_printed != linenum)) {
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				print_line(line, linenum, '-');
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				print_n_lines_after--;
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			}
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#endif /* CONFIG_FEATURE_GREP_CONTEXT */ 
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		} /* for */
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		free(line);
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	}
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	/* special-case file post-processing for options where we don't print line
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	 * matches, just filenames and possibly match counts */
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	/* grep -c: print [filename:]count, even if count is zero */
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	if (print_match_counts) {
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		if (print_filename)
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			printf("%s:", cur_file);
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		if (print_files_with_matches && nmatches > 0)
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			printf("1\n");
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		else
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		    printf("%d\n", nmatches);
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	}
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	/* grep -l: print just the filename, but only if we grepped the line in the file  */
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	if (print_files_with_matches && nmatches > 0) {
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		puts(cur_file);
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	}
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	/* remember if we matched */
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	if (nmatches != 0)
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		matched = 1;
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}
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static void add_regex(const char *restr)
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{
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	regexes = xrealloc(regexes, sizeof(regex_t) * (++nregexes));
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	xregcomp(®exes[nregexes-1], restr, reflags);
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}
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static void	load_regexes_from_file(const char *filename)
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{
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	char *line;
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	FILE *f = xfopen(filename, "r");
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	while ((line = get_line_from_file(f)) != NULL) {
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		chomp(line);
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		add_regex(line);
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		free(line);
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	}
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}
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#ifdef CONFIG_FEATURE_CLEAN_UP
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static void destroy_regexes(void)
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{
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	if (regexes == NULL)
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		return;
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	/* destroy all the elments in the array */
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	while (--nregexes >= 0) {
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		regfree(&(regexes[nregexes]));
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	}
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	if (regexes)
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	    free(regexes);
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}
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#endif
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extern int grep_main(int argc, char **argv)
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{
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	int opt;
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#if defined (CONFIG_FEATURE_GREP_CONTEXT)
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	char *junk;
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#endif
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#ifdef CONFIG_FEATURE_CLEAN_UP
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	/* destroy command strings on exit */
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	atexit(destroy_regexes);
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#endif
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#ifdef CONFIG_FEATURE_GREP_EGREP_ALIAS
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	if (strcmp(get_last_path_component(argv[0]), "egrep") == 0)
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		reflags |= REG_EXTENDED;
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#endif
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	/* do normal option parsing */
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	while ((opt = getopt(argc, argv, "iHhlnqvsce:f:"
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#ifdef CONFIG_FEATURE_GREP_CONTEXT
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"A:B:C:"
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#endif
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#ifdef CONFIG_FEATURE_GREP_EGREP_ALIAS
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"E"
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#endif
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)) > 0) {
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		switch (opt) {
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			case 'i':
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				reflags |= REG_ICASE;
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				break;
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			case 'l':
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				print_files_with_matches++;
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				break;
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			case 'H':
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				print_filename++;
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				break;
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			case 'h':
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				print_filename--;
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				break;
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			case 'n':
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				print_line_num++;
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				break;
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			case 'q':
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				be_quiet++;
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				break;
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			case 'v':
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				invert_search++;
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				break;
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			case 's':
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				suppress_err_msgs++;
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				break;
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			case 'c':
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				print_match_counts++;
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				break;
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			case 'e':
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				add_regex(optarg);
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				break;
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#ifdef CONFIG_FEATURE_GREP_EGREP_ALIAS
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			case 'E':
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				reflags |= REG_EXTENDED;
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				break;
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#endif
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			case 'f':
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				load_regexes_from_file(optarg);
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				break;
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#ifdef CONFIG_FEATURE_GREP_CONTEXT
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			case 'A':
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				lines_after = strtoul(optarg, &junk, 10);
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				if(*junk != '\0')
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					error_msg_and_die("invalid context length argument");
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				break;
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			case 'B':
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				lines_before = strtoul(optarg, &junk, 10);
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				if(*junk != '\0')
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					error_msg_and_die("invalid context length argument");
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				before_buf = (char **)xcalloc(lines_before, sizeof(char *));
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				break;
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			case 'C':
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				lines_after = lines_before = strtoul(optarg, &junk, 10);
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				if(*junk != '\0')
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					error_msg_and_die("invalid context length argument");
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				before_buf = (char **)xcalloc(lines_before, sizeof(char *));
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				break;
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#endif /* CONFIG_FEATURE_GREP_CONTEXT */
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			default:
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				show_usage();
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		}
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	}
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	/* if we didn't get a pattern from a -e and no command file was specified,
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	 * argv[optind] should be the pattern. no pattern, no worky */
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	if (nregexes == 0) {
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		if (argv[optind] == NULL)
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			show_usage();
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		else {
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			add_regex(argv[optind]);
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			optind++;
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		}
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	}
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	/* sanity checks */
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	if (print_match_counts || be_quiet || print_files_with_matches) {
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		print_line_num = 0;
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#ifdef CONFIG_FEATURE_GREP_CONTEXT
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		lines_before = 0;
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		lines_after = 0;
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#endif
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	}
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	/* argv[(optind)..(argc-1)] should be names of file to grep through. If
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	 * there is more than one file to grep, we will print the filenames */
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	if ((argc-1) - (optind) > 0)
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		print_filename++;
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	/* If no files were specified, or '-' was specified, take input from
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	 * stdin. Otherwise, we grep through all the files specified. */
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	if (argv[optind] == NULL || (strcmp(argv[optind], "-") == 0)) {
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		grep_file(stdin);
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	}
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	else {
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		int i;
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		FILE *file;
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		for (i = optind; i < argc; i++) {
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			cur_file = argv[i];
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			file = fopen(cur_file, "r");
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			if (file == NULL) {
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				if (!suppress_err_msgs)
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					perror_msg("%s", cur_file);
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			}
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			else {
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				grep_file(file);
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				fclose(file);
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			}
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		}
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	}
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	return !matched; /* invert return value 0 = success, 1 = failed */
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}
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