grep.c

   1 /*
   2  * Mini grep implementation for busybox using libc regex.
   3  *
   4  * Copyright (C) 1999,2000,2001 by Lineo, inc.
   5  * Written by Mark Whitley <markw@lineo.com>, <markw@codepoet.org>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  15  * General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  20  *
  21  */
  22
  23 #include <stdio.h>
  24 #include <stdlib.h>
  25 #include <getopt.h>
  26 #include <regex.h>
  27 #include <string.h> /* for strerror() */
  28 #include <errno.h>
  29 #include "busybox.h"
  30
  31
  32 extern int optind; /* in unistd.h */
  33 extern int errno;  /* for use with strerror() */
  34 extern void xregcomp(regex_t *preg, const char *regex, int cflags); /* in busybox.h */
  35
  36 /* options */
  37 static int ignore_case       = 0;
  38 static int print_filename    = 0;
  39 static int print_line_num    = 0;
  40 static int print_match_counts  = 0;
  41 static int be_quiet          = 0;
  42 static int invert_search     = 0;
  43 static int suppress_err_msgs = 0;
  44 static int print_files_with_matches  = 0;
  45
  46 #ifdef BB_FEATURE_GREP_CONTEXT
  47 extern char *optarg; /* in getopt.h */
  48 static int lines_before      = 0;
  49 static int lines_after       = 0;
  50 static char **before_buf     = NULL;
  51 static int last_line_printed = 0;
  52 #endif /* BB_FEATURE_GREP_CONTEXT */
  53
  54 /* globals used internally */
  55 static regex_t regex; /* storage space for compiled regular expression */
  56 static int matched; /* keeps track of whether we ever matched */
  57 static char *cur_file = NULL; /* the current file we are reading */
  58
  59 static void print_line(const char *line, int linenum, char decoration)
  60 {
  61 #ifdef BB_FEATURE_GREP_CONTEXT
  62         /* possibly print the little '--' seperator */
  63         if (last_line_printed && last_line_printed < linenum - 1) {
  64                 puts("--");
  65         }
  66         last_line_printed = linenum;
  67 #endif
  68         if (print_filename)
  69                 printf("%s%c", cur_file, decoration);
  70         if (print_line_num)
  71                 printf("%i%c", linenum, decoration);
  72         puts(line);
  73 }
  74
  75 static void grep_file(FILE *file)
  76 {
  77         char *line = NULL;
  78         int ret;
  79         int linenum = 0;
  80         int nmatches = 0;
  81 #ifdef BB_FEATURE_GREP_CONTEXT
  82         int print_n_lines_after = 0;
  83         int curpos = 0; /* track where we are in the circular 'before' buffer */
  84         int idx = 0; /* used for iteration through the circular buffer */
  85 #endif /* BB_FEATURE_GREP_CONTEXT */
  86
  87         while ((line = get_line_from_file(file)) != NULL) {
  88                 chomp(line);
  89                 linenum++;
  90
  91                 /*
  92                  * test for a postitive-assertion match (regexec returns success (0)
  93                  * and the user did not specify invert search), or a negative-assertion
  94                  * match (regexec returns failure (REG_NOMATCH) and the user specified
  95                  * invert search)
  96                  */
  97                 ret = regexec(&regex, line, 0, NULL, 0);
  98                 if ((ret == 0 && !invert_search) || (ret == REG_NOMATCH && invert_search)) {
  99
 100                         /* if we found a match but were told to be quiet, stop here and
 101                          * return success */
 102                         if (be_quiet) {
 103                                 regfree(&regex);
 104                                 exit(0);
 105                         }
 106
 107                         /* keep track of matches */
 108                         nmatches++;
 109
 110                         /* if we're just printing filenames, we stop after the first match */
 111                         if (print_files_with_matches)
 112                                 break;
 113
 114                         /* print the matched line */
 115                         if (print_match_counts == 0) {
 116 #ifdef BB_FEATURE_GREP_CONTEXT
 117                                 int prevpos = (curpos == 0) ? lines_before - 1 : curpos - 1;
 118
 119                                 /* if we were told to print 'before' lines and there is at least
 120                                  * one line in the circular buffer, print them */
 121                                 if (lines_before && before_buf[prevpos] != NULL) {
 122                                         int first_buf_entry_line_num = linenum - lines_before;
 123
 124                                         /* advance to the first entry in the circular buffer, and
 125                                          * figure out the line number is of the first line in the
 126                                          * buffer */
 127                                         idx = curpos;
 128                                         while (before_buf[idx] == NULL) {
 129                                                 idx = (idx + 1) % lines_before;
 130                                                 first_buf_entry_line_num++;
 131                                         }
 132
 133                                         /* now print each line in the buffer, clearing them as we go */
 134                                         while (before_buf[idx] != NULL) {
 135                                                 print_line(before_buf[idx], first_buf_entry_line_num, '-');
 136                                                 free(before_buf[idx]);
 137                                                 before_buf[idx] = NULL;
 138                                                 idx = (idx + 1) % lines_before;
 139                                                 first_buf_entry_line_num++;
 140                                         }
 141                                 }
 142
 143                                 /* make a note that we need to print 'after' lines */
 144                                 print_n_lines_after = lines_after;
 145 #endif /* BB_FEATURE_GREP_CONTEXT */
 146                                 print_line(line, linenum, ':');
 147                         }
 148                 }
 149 #ifdef BB_FEATURE_GREP_CONTEXT
 150                 else { /* no match */
 151                         /* Add the line to the circular 'before' buffer */
 152                         if(lines_before) {
 153                                 if(before_buf[curpos])
 154                                         free(before_buf[curpos]);
 155                                 before_buf[curpos] = strdup(line);
 156                                 curpos = (curpos + 1) % lines_before;
 157                         }
 158                 }
 159
 160                 /* if we need to print some context lines after the last match, do so */
 161                 if (print_n_lines_after && (last_line_printed != linenum)) {
 162                         print_line(line, linenum, '-');
 163                         print_n_lines_after--;
 164                 }
 165 #endif /* BB_FEATURE_GREP_CONTEXT */
 166                 free(line);
 167         }
 168
 169
 170         /* special-case file post-processing for options where we don't print line
 171          * matches, just filenames and possibly match counts */
 172
 173         /* grep -c: print [filename:]count, even if count is zero */
 174         if (print_match_counts) {
 175                 if (print_filename)
 176                         printf("%s:", cur_file);
 177                 printf("%d\n", nmatches);
 178         }
 179
 180         /* grep -l: print just the filename, but only if we grepped the line in the file  */
 181         if (print_files_with_matches && nmatches > 0) {
 182                 puts(cur_file);
 183         }
 184
 185
 186         /* remember if we matched */
 187         if (nmatches != 0)
 188                 matched = 1;
 189 }
 190
 191 extern int grep_main(int argc, char **argv)
 192 {
 193         int opt;
 194         int reflags;
 195 #ifdef BB_FEATURE_GREP_CONTEXT
 196         char *junk;
 197 #endif
 198
 199         /* do normal option parsing */
 200         while ((opt = getopt(argc, argv, "iHhlnqvsc"
 201 #ifdef BB_FEATURE_GREP_CONTEXT
 202 "A:B:C:"
 203 #endif
 204 )) > 0) {
 205                 switch (opt) {
 206                         case 'i':
 207                                 ignore_case++;
 208                                 break;
 209                         case 'l':
 210                                 print_files_with_matches++;
 211                                 break;
 212                         case 'H':
 213                                 print_filename++;
 214                                 break;
 215                         case 'h':
 216                                 print_filename--;
 217                                 break;
 218                         case 'n':
 219                                 print_line_num++;
 220                                 break;
 221                         case 'q':
 222                                 be_quiet++;
 223                                 break;
 224                         case 'v':
 225                                 invert_search++;
 226                                 break;
 227                         case 's':
 228                                 suppress_err_msgs++;
 229                                 break;
 230                         case 'c':
 231                                 print_match_counts++;
 232                                 break;
 233 #ifdef BB_FEATURE_GREP_CONTEXT
 234                         case 'A':
 235                                 lines_after = strtoul(optarg, &junk, 10);
 236                                 if(*junk != '\0')
 237                                         error_msg_and_die("invalid context length argument");
 238                                 break;
 239                         case 'B':
 240                                 lines_before = strtoul(optarg, &junk, 10);
 241                                 if(*junk != '\0')
 242                                         error_msg_and_die("invalid context length argument");
 243                                 before_buf = (char **)calloc(lines_before, sizeof(char *));
 244                                 break;
 245                         case 'C':
 246                                 lines_after = lines_before = strtoul(optarg, &junk, 10);
 247                                 if(*junk != '\0')
 248                                         error_msg_and_die("invalid context length argument");
 249                                 before_buf = (char **)calloc(lines_before, sizeof(char *));
 250                                 break;
 251 #endif /* BB_FEATURE_GREP_CONTEXT */
 252                         default:
 253                                 show_usage();
 254                 }
 255         }
 256
 257         /* argv[optind] should be the regex pattern; no pattern, no worky */
 258         if (argv[optind] == NULL)
 259                 show_usage();
 260
 261         /* sanity check */
 262         if (print_match_counts || be_quiet || print_files_with_matches) {
 263                 print_line_num = 0;
 264 #ifdef BB_FEATURE_GREP_CONTEXT
 265                 lines_before = 0;
 266                 lines_after = 0;
 267 #endif
 268         }
 269
 270         /* compile the regular expression
 271          * we're not going to mess with sub-expressions, and we need to
 272          * treat newlines right. */
 273         reflags = REG_NOSUB;
 274         if (ignore_case)
 275                 reflags |= REG_ICASE;
 276         xregcomp(&regex, argv[optind], reflags);
 277
 278         /* argv[(optind+1)..(argc-1)] should be names of file to grep through. If
 279          * there is more than one file to grep, we will print the filenames */
 280         if ((argc-1) - (optind+1) > 0)
 281                 print_filename++;
 282
 283         /* If no files were specified, or '-' was specified, take input from
 284          * stdin. Otherwise, we grep through all the files specified. */
 285         if (argv[optind+1] == NULL || (strcmp(argv[optind+1], "-") == 0)) {
 286                 grep_file(stdin);
 287         }
 288         else {
 289                 int i;
 290                 FILE *file;
 291                 for (i = optind + 1; i < argc; i++) {
 292                         cur_file = argv[i];
 293                         file = fopen(cur_file, "r");
 294                         if (file == NULL) {
 295                                 if (!suppress_err_msgs)
 296                                         perror_msg("%s", cur_file);
 297                         }
 298                         else {
 299                                 grep_file(file);
 300                                 fclose(file);
 301                         }
 302                 }
 303         }
 304
 305         regfree(&regex);
 306
 307         return !matched; /* invert return value 0 = success, 1 = failed */
 308 }