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_count_only  = 0;
  41 static int be_quiet          = 0;
  42 static int invert_search     = 0;
  43 static int suppress_err_msgs = 0;
  44
  45 #ifdef BB_FEATURE_GREP_CONTEXT
  46 extern char *optarg; /* in getopt.h */
  47 static int lines_before      = 0;
  48 static int lines_after       = 0;
  49 static char **before_buf     = NULL;
  50 static int last_line_printed = 0;
  51 #endif /* BB_FEATURE_GREP_CONTEXT */
  52
  53 /* globals used internally */
  54 static regex_t regex; /* storage space for compiled regular expression */
  55 static int matched; /* keeps track of whether we ever matched */
  56 static char *cur_file = NULL; /* the current file we are reading */
  57
  58 static void print_line(const char *line, int linenum, char decoration)
  59 {
  60 #ifdef BB_FEATURE_GREP_CONTEXT
  61         /* possibly print the little '--' seperator */
  62         if (last_line_printed && last_line_printed < linenum - 1) {
  63                 puts("--");
  64         }
  65         last_line_printed = linenum;
  66 #endif
  67         if (print_filename)
  68                 printf("%s%c", cur_file, decoration);
  69         if (print_line_num)
  70                 printf("%i%c", linenum, decoration);
  71         puts(line);
  72 }
  73
  74 static void grep_file(FILE *file)
  75 {
  76         char *line = NULL;
  77         int ret;
  78         int linenum = 0;
  79         int nmatches = 0;
  80 #ifdef BB_FEATURE_GREP_CONTEXT
  81         int print_n_lines_after = 0;
  82         int curpos = 0; /* track where we are in the circular 'before' buffer */
  83         int idx = 0; /* used for iteration through the circular buffer */
  84 #endif /* BB_FEATURE_GREP_CONTEXT */
  85
  86         while ((line = get_line_from_file(file)) != NULL) {
  87                 chomp(line);
  88                 linenum++;
  89
  90                 /*
  91                  * test for a postitive-assertion match (regexec returns success (0)
  92                  * and the user did not specify invert search), or a negative-assertion
  93                  * match (regexec returns failure (REG_NOMATCH) and the user specified
  94                  * invert search)
  95                  */
  96                 ret = regexec(&regex, line, 0, NULL, 0);
  97                 if ((ret == 0 && !invert_search) || (ret == REG_NOMATCH && invert_search)) {
  98
  99                         /* if we found a match but were told to be quiet, stop here and
 100                          * return success */
 101                         if (be_quiet) {
 102                                 regfree(&regex);
 103                                 exit(0);
 104                         }
 105
 106                         /* otherwise, keep track of matches and print the matched line */
 107                         nmatches++;
 108                         if (!print_count_only) {
 109 #ifdef BB_FEATURE_GREP_CONTEXT
 110                                 int prevpos = (curpos == 0) ? lines_before - 1 : curpos - 1;
 111
 112                                 /* if we were told to print 'before' lines and there is at least
 113                                  * one line in the circular buffer, print them */
 114                                 if (lines_before && before_buf[prevpos] != NULL)
 115                                 {
 116                                         int first_buf_entry_line_num = linenum - lines_before;
 117
 118                                         /* advance to the first entry in the circular buffer, and
 119                                          * figure out the line number is of the first line in the
 120                                          * buffer */
 121                                         idx = curpos;
 122                                         while (before_buf[idx] == NULL) {
 123                                                 idx = (idx + 1) % lines_before;
 124                                                 first_buf_entry_line_num++;
 125                                         }
 126
 127                                         /* now print each line in the buffer, clearing them as we go */
 128                                         while (before_buf[idx] != NULL) {
 129                                                 print_line(before_buf[idx], first_buf_entry_line_num, '-');
 130                                                 free(before_buf[idx]);
 131                                                 before_buf[idx] = NULL;
 132                                                 idx = (idx + 1) % lines_before;
 133                                                 first_buf_entry_line_num++;
 134                                         }
 135
 136                                 }
 137
 138                                 /* make a note that we need to print 'after' lines */
 139                                 print_n_lines_after = lines_after;
 140 #endif /* BB_FEATURE_GREP_CONTEXT */
 141                                 print_line(line, linenum, ':');
 142                         }
 143                 }
 144 #ifdef BB_FEATURE_GREP_CONTEXT
 145                 else { /* no match */
 146                         /* Add the line to the circular 'before' buffer */
 147                         if(lines_before)
 148                         {
 149                                 if(before_buf[curpos])
 150                                         free(before_buf[curpos]);
 151                                 before_buf[curpos] = strdup(line);
 152                                 curpos = (curpos + 1) % lines_before;
 153                         }
 154                 }
 155
 156                 /* if we need to print some context lines after the last match, do so */
 157                 if (print_n_lines_after && (last_line_printed != linenum)) {
 158                         print_line(line, linenum, '-');
 159                         print_n_lines_after--;
 160                 }
 161 #endif /* BB_FEATURE_GREP_CONTEXT */
 162                 free(line);
 163         }
 164
 165         /* special-case post processing */
 166         if (print_count_only) {
 167                 if (print_filename)
 168                         printf("%s:", cur_file);
 169                 printf("%i\n", nmatches);
 170         }
 171
 172         /* remember if we matched */
 173         if (nmatches != 0)
 174                 matched = 1;
 175 }
 176
 177 extern int grep_main(int argc, char **argv)
 178 {
 179         int opt;
 180         int reflags;
 181 #ifdef BB_FEATURE_GREP_CONTEXT
 182         char *junk;
 183 #endif
 184
 185         /* do normal option parsing */
 186         while ((opt = getopt(argc, argv, "iHhnqvsc"
 187 #ifdef BB_FEATURE_GREP_CONTEXT
 188 "A:B:C:"
 189 #endif
 190 )) > 0) {
 191                 switch (opt) {
 192                         case 'i':
 193                                 ignore_case++;
 194                                 break;
 195                         case 'H':
 196                                 print_filename++;
 197                                 break;
 198                         case 'h':
 199                                 print_filename--;
 200                                 break;
 201                         case 'n':
 202                                 print_line_num++;
 203                                 break;
 204                         case 'q':
 205                                 be_quiet++;
 206                                 break;
 207                         case 'v':
 208                                 invert_search++;
 209                                 break;
 210                         case 's':
 211                                 suppress_err_msgs++;
 212                                 break;
 213                         case 'c':
 214                                 print_count_only++;
 215                                 break;
 216 #ifdef BB_FEATURE_GREP_CONTEXT
 217                         case 'A':
 218                                 lines_after = strtoul(optarg, &junk, 10);
 219                                 if(*junk != '\0')
 220                                         error_msg_and_die("invalid context length argument");
 221                                 break;
 222                         case 'B':
 223                                 lines_before = strtoul(optarg, &junk, 10);
 224                                 if(*junk != '\0')
 225                                         error_msg_and_die("invalid context length argument");
 226                                 before_buf = (char **)calloc(lines_before, sizeof(char *));
 227                                 break;
 228                         case 'C':
 229                                 lines_after = lines_before = strtoul(optarg, &junk, 10);
 230                                 if(*junk != '\0')
 231                                         error_msg_and_die("invalid context length argument");
 232                                 before_buf = (char **)calloc(lines_before, sizeof(char *));
 233                                 break;
 234 #endif /* BB_FEATURE_GREP_CONTEXT */
 235                 }
 236         }
 237
 238         /* argv[optind] should be the regex pattern; no pattern, no worky */
 239         if (argv[optind] == NULL)
 240                 show_usage();
 241
 242         /* sanity check */
 243         if (print_count_only || be_quiet) {
 244                 print_line_num = 0;
 245 #ifdef BB_FEATURE_GREP_CONTEXT
 246                 lines_before = 0;
 247                 lines_after = 0;
 248 #endif
 249         }
 250
 251         /* compile the regular expression
 252          * we're not going to mess with sub-expressions, and we need to
 253          * treat newlines right. */
 254         reflags = REG_NOSUB;
 255         if (ignore_case)
 256                 reflags |= REG_ICASE;
 257         xregcomp(&regex, argv[optind], reflags);
 258
 259         /* argv[(optind+1)..(argc-1)] should be names of file to grep through. If
 260          * there is more than one file to grep, we will print the filenames */
 261         if ((argc-1) - (optind+1) > 0)
 262                 print_filename++;
 263
 264         /* If no files were specified, or '-' was specified, take input from
 265          * stdin. Otherwise, we grep through all the files specified. */
 266         if (argv[optind+1] == NULL || (strcmp(argv[optind+1], "-") == 0)) {
 267                 grep_file(stdin);
 268         }
 269         else {
 270                 int i;
 271                 FILE *file;
 272                 for (i = optind + 1; i < argc; i++) {
 273                         cur_file = argv[i];
 274                         file = fopen(cur_file, "r");
 275                         if (file == NULL) {
 276                                 if (!suppress_err_msgs)
 277                                         perror_msg("%s", cur_file);
 278                         }
 279                         else {
 280                                 grep_file(file);
 281                                 fclose(file);
 282                         }
 283                 }
 284         }
 285
 286         regfree(&regex);
 287
 288         return !matched; /* invert return value 0 = success, 1 = failed */
 289 }