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525 lines
13 KiB
C
525 lines
13 KiB
C
/*
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* sed.c - very minimalist version of sed
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*
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* Copyright (C) 1999,2000 by Lineo, inc.
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* Written by Mark Whitley <markw@lineo.com>, <markw@enol.com>
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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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/*
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Supported features and commands in this version of sed:
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- comments ('#')
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- Address matching: num|/matchstr/[,num|/matchstr/|$]command
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- Commands: p, d, s/match/replace/[g]
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(Note: Specifying an address (range) to match is *optional*; commands
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default to the whole pattern space if no specific address match was
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requested.)
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Unsupported features:
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- transliteration (y/source-chars/dest-chars/) (use 'tr')
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- no support for characters other than the '/' character for regex matches
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- no pattern space hold space storing / swapping (x, etc.)
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- no labels / branching (: label, b, t, and friends)
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- and lots, lots more.
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*/
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#include <stdio.h>
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#include <stdlib.h> /* for realloc() */
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#include <unistd.h> /* for getopt() */
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#include <regex.h>
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#include <string.h> /* for strdup() */
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#include <errno.h>
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#include <ctype.h> /* for isspace() */
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#include "internal.h"
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/* externs */
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extern int optind; /* in unistd.h */
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extern char *optarg; /* ditto */
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/* options */
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static int be_quiet = 0;
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struct sed_cmd {
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/* address storage */
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int beg_line; /* 'sed 1p' 0 == no begining line, apply commands to all lines */
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int end_line; /* 'sed 1,3p' 0 == no end line, use only beginning. -1 == $ */
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regex_t *beg_match; /* sed -e '/match/cmd' */
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regex_t *end_match; /* sed -e '/match/,/end_match/cmd' */
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/* the command */
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char cmd; /* p,d,s (add more at your leisure :-) */
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/* substitution command specific fields */
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regex_t *sub_match; /* sed -e 's/sub_match/replace/' */
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char *replace; /* sed -e 's/sub_match/replace/' XXX: who will hold the \1 \2 \3s? */
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unsigned int sub_g:1; /* sed -e 's/foo/bar/g' (global) */
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};
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/* globals */
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static struct sed_cmd *sed_cmds = NULL; /* growable arrary holding a sequence of sed cmds */
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static int ncmds = 0; /* number of sed commands */
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/*static char *cur_file = NULL;*/ /* file currently being processed XXX: do I need this? */
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static const char sed_usage[] =
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"sed [-Vhnef] pattern [files...]\n"
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#ifndef BB_FEATURE_TRIVIAL_HELP
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"\n"
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"-n\tsuppress automatic printing of pattern space\n"
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"-e script\tadd the script to the commands to be executed\n"
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"-f scriptfile\tadd the contents of script-file to the commands to be executed\n"
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"-h\tdisplay this help message\n"
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"-V\toutput version information and exit\n"
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"\n"
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"If no -e or -f is given, the first non-option argument is taken as the\n"
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"sed script to interpret. All remaining arguments are names of input\n"
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"files; if no input files are specified, then the standard input is read.\n"
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#endif
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;
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static void destroy_cmd_strs()
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{
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if (sed_cmds == NULL)
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return;
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/* destroy all the elements in the array */
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while (--ncmds >= 0) {
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if (sed_cmds[ncmds].beg_match) {
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regfree(sed_cmds[ncmds].beg_match);
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free(sed_cmds[ncmds].beg_match);
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}
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if (sed_cmds[ncmds].end_match) {
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regfree(sed_cmds[ncmds].end_match);
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free(sed_cmds[ncmds].end_match);
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}
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if (sed_cmds[ncmds].sub_match) {
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regfree(sed_cmds[ncmds].sub_match);
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free(sed_cmds[ncmds].sub_match);
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}
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if (sed_cmds[ncmds].replace)
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free(sed_cmds[ncmds].replace);
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}
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/* destroy the array */
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free(sed_cmds);
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sed_cmds = NULL;
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}
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/*
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* trim_str - trims leading and trailing space from a string
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*
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* Note: This returns a malloc'ed string so you must store and free it
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* XXX: This should be in the utility.c file.
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*/
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static char *trim_str(const char *str)
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{
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int i;
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char *retstr = strdup(str);
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/* trim leading whitespace */
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memmove(retstr, &retstr[strspn(retstr, " \n\t\v")], strlen(retstr));
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/* trim trailing whitespace */
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i = strlen(retstr) - 1;
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while (isspace(retstr[i]))
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i--;
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retstr[++i] = 0;
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/* Aside:
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*
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* you know, a strrspn() would really be nice cuz then we could say:
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*
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* retstr[strlen(retstr) - strrspn(retstr, " \n\t\v") + 1] = 0;
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*/
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return retstr;
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}
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/*
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* index_of_unescaped_slash - walks left to right through a string beginning
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* at a specified index and returns the index of the next unescaped slash.
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*/
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static int index_of_next_unescaped_slash(int idx, const char *str)
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{
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do {
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idx++;
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/* test if we've hit the end */
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if (str[idx] == 0)
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return -1;
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} while (str[idx] != '/' && str[idx - 1] != '\\');
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return idx;
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}
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/*
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* returns the index in the string just past where the address ends.
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*/
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static int get_address(const char *str, int *line, regex_t **regex)
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{
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char *my_str = strdup(str);
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int idx = 0;
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if (isdigit(my_str[idx])) {
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do {
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idx++;
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} while (isdigit(my_str[idx]));
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my_str[idx] = 0;
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*line = atoi(my_str);
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*regex = NULL;
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}
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else if (my_str[idx] == '$') {
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*line = -1;
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*regex = NULL;
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idx++;
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}
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else if (my_str[idx] == '/') {
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idx = index_of_next_unescaped_slash(idx, my_str);
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if (idx == -1)
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fatalError("unterminated match expression\n");
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my_str[idx] = '\0';
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*regex = (regex_t *)xmalloc(sizeof(regex_t));
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if (bb_regcomp(*regex, my_str+1, REG_NEWLINE) != 0) {
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free(my_str);
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exit(1);
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}
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}
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else {
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fprintf(stderr, "sed.c:get_address: no address found in string\n");
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fprintf(stderr, "\t(you probably didn't check the string you passed me)\n");
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idx = -1;
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}
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free(my_str);
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return idx;
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}
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static char *strdup_substr(const char *str, int start, int end)
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{
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int size = end - start + 1;
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char *newstr = xmalloc(size);
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memcpy(newstr, str+start, size-1);
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newstr[size-1] = '\0';
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return newstr;
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}
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static void parse_cmd_str(struct sed_cmd *sed_cmd, const char *cmdstr)
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{
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int idx = 0;
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/* parse the command
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* format is: [addr][,addr]cmd
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* |----||-----||-|
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* part1 part2 part3
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*/
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/* first part (if present) is an address: either a number or a /regex/ */
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if (isdigit(cmdstr[idx]) || cmdstr[idx] == '/')
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idx = get_address(cmdstr, &sed_cmd->beg_line, &sed_cmd->beg_match);
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/* second part (if present) will begin with a comma */
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if (cmdstr[idx] == ',')
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idx += get_address(&cmdstr[++idx], &sed_cmd->end_line, &sed_cmd->end_match);
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/* last part (mandatory) will be a command */
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if (cmdstr[idx] == '\0')
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fatalError("missing command\n");
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if (!strchr("pds", cmdstr[idx])) /* <-- XXX add new commands here */
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fatalError("invalid command\n");
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sed_cmd->cmd = cmdstr[idx];
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/* special-case handling for 's' */
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if (sed_cmd->cmd == 's') {
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int oldidx, cflags = REG_NEWLINE;
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char *match;
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/* format for substitution is:
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* s/match/replace/gI
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* | ||
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* mandatory optional
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*/
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/* verify that we have an 's' followed by a 'slash' */
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if (cmdstr[++idx] != '/')
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fatalError("bad format in substitution expression\n");
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/* save the match string */
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oldidx = idx+1;
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idx = index_of_next_unescaped_slash(idx, cmdstr);
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if (idx == -1)
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fatalError("bad format in substitution expression\n");
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match = strdup_substr(cmdstr, oldidx, idx);
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/* save the replacement string */
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oldidx = idx+1;
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idx = index_of_next_unescaped_slash(idx, cmdstr);
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if (idx == -1)
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fatalError("bad format in substitution expression\n");
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sed_cmd->replace = strdup_substr(cmdstr, oldidx, idx);
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/* process the flags */
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while (cmdstr[++idx]) {
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switch (cmdstr[idx]) {
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case 'g':
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sed_cmd->sub_g = 1;
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break;
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case 'I':
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cflags |= REG_ICASE;
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break;
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default:
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fatalError("bad option in substitution expression\n");
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}
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}
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/* compile the regex */
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sed_cmd->sub_match = (regex_t *)xmalloc(sizeof(regex_t));
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if (bb_regcomp(sed_cmd->sub_match, match, cflags) != 0) {
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free(match);
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exit(1);
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}
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free(match);
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}
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}
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static void add_cmd_str(const char *cmdstr)
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{
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char *my_cmdstr = trim_str(cmdstr);
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/* if this is a comment, don't even bother */
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if (my_cmdstr[0] == '#') {
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free(my_cmdstr);
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return;
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}
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/* grow the array */
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sed_cmds = realloc(sed_cmds, sizeof(struct sed_cmd) * (++ncmds));
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/* zero new element */
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memset(&sed_cmds[ncmds-1], 0, sizeof(struct sed_cmd));
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/* load command string into new array element */
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parse_cmd_str(&sed_cmds[ncmds-1], my_cmdstr);
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}
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static void load_cmd_file(char *filename)
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{
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FILE *cmdfile;
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char *line;
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cmdfile = fopen(filename, "r");
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if (cmdfile == NULL)
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fatalError(strerror(errno));
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while ((line = get_line_from_file(cmdfile)) != NULL) {
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line[strlen(line)-1] = 0; /* eat newline */
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add_cmd_str(line);
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free(line);
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}
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}
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static int do_sed_command(const struct sed_cmd *sed_cmd, const char *line)
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{
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int altered = 0;
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switch (sed_cmd->cmd) {
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case 'p':
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fputs(line, stdout);
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break;
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case 'd':
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altered++;
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break;
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case 's': /* oo, a fun one :-) */
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/* we only substitute if the substitution 'search' expression matches */
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if (regexec(sed_cmd->sub_match, line, 0, NULL, 0) == 0) {
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regmatch_t regmatch;
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int i;
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char *ptr = (char *)line;
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while (*ptr) {
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/* if we can match the search string... */
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if (regexec(sed_cmd->sub_match, ptr, 1, ®match, 0) == 0) {
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/* print everything before the match, */
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for (i = 0; i < regmatch.rm_so; i++)
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fputc(ptr[i], stdout);
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/* then print the substitution in its place */
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fputs(sed_cmd->replace, stdout);
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/* then advance past the match */
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ptr += regmatch.rm_eo;
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/* and let the calling function know that something
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* has been changed */
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altered++;
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/* if we're not doing this globally... */
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if (!sed_cmd->sub_g)
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break;
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}
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/* if we COULD NOT match the search string (meaning we've gone past
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* all previous instances), get out */
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else
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break;
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}
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/* is there anything left to print? */
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if (*ptr)
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fputs(ptr, stdout);
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}
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break;
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}
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return altered;
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}
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static void process_file(FILE *file)
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{
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char *line = NULL;
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static int linenum = 0; /* GNU sed does not restart counting lines at EOF */
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unsigned int still_in_range = 0;
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int line_altered;
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int i;
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/* go through every line in the file */
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while ((line = get_line_from_file(file)) != NULL) {
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linenum++;
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line_altered = 0;
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/* for every line, go through all the commands */
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for (i = 0; i < ncmds; i++) {
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/* are we acting on a range of matched lines? */
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if (sed_cmds[i].beg_match && sed_cmds[i].end_match) {
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if (still_in_range || regexec(sed_cmds[i].beg_match, line, 0, NULL, 0) == 0) {
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line_altered += do_sed_command(&sed_cmds[i], line);
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still_in_range = 1;
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if (regexec(sed_cmds[i].end_match, line, 0, NULL, 0) == 0)
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still_in_range = 0;
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}
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}
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/* are we trying to match a single line? */
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else if (sed_cmds[i].beg_match) {
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if (regexec(sed_cmds[i].beg_match, line, 0, NULL, 0) == 0)
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line_altered += do_sed_command(&sed_cmds[i], line);
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}
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/* are we acting on a range of line numbers? */
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else if (sed_cmds[i].beg_line > 0 && sed_cmds[i].end_line > 0) {
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if (linenum >= sed_cmds[i].beg_line && linenum <= sed_cmds[i].end_line)
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line_altered += do_sed_command(&sed_cmds[i], line);
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}
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/* are we acting on a specified line number */
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else if (sed_cmds[i].beg_line > 0) {
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if (linenum == sed_cmds[i].beg_line)
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line_altered += do_sed_command(&sed_cmds[i], line);
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}
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/* not acting on matches or line numbers. act on every line */
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else
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line_altered += do_sed_command(&sed_cmds[i], line);
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}
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/* we will print the line unless we were told to be quiet or if the
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* line was altered (via a 'd'elete or 's'ubstitution) */
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if (!be_quiet && !line_altered)
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fputs(line, stdout);
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free(line);
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}
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}
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extern int sed_main(int argc, char **argv)
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{
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int opt;
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/* do special-case option parsing */
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if (argv[1] && (strcmp(argv[1], "--help") == 0))
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usage(sed_usage);
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/* destroy command strings on exit */
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if (atexit(destroy_cmd_strs) == -1) {
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perror("sed");
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exit(1);
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}
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/* do normal option parsing */
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while ((opt = getopt(argc, argv, "Vhne:f:")) > 0) {
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switch (opt) {
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case 'V':
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printf("Print Busybox version here\n");
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exit(0);
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break;
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case 'h':
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usage(sed_usage);
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break;
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case 'n':
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be_quiet++;
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break;
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case 'e':
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add_cmd_str(optarg);
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break;
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case 'f':
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load_cmd_file(optarg);
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break;
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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 (ncmds == 0) {
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if (argv[optind] == NULL)
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usage(sed_usage);
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else {
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add_cmd_str(argv[optind]);
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optind++;
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}
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}
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/* argv[(optind)..(argc-1)] should be names of file to process. If no
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* files were specified or '-' was specified, take input from stdin.
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* Otherwise, we process all the files specified. */
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if (argv[optind] == NULL || (strcmp(argv[optind], "-") == 0)) {
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process_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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file = fopen(argv[i], "r");
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if (file == NULL) {
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fprintf(stderr, "sed: %s: %s\n", argv[i], strerror(errno));
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} else {
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process_file(file);
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fclose(file);
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}
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}
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}
|
|
|
|
return 0;
|
|
}
|