Thought of another janitorial item for the list.
[oweals/busybox.git] / grep.c
diff --git a/grep.c b/grep.c
index 3779e5510a9eda7ea7ae988f140bfc40b003e63c..475b4ef212c1e79950609fc990331587df785638 100644 (file)
--- a/grep.c
+++ b/grep.c
 /*
- * Copyright (c) 1999 by David I. Bell
- * Permission is granted to use, distribute, or modify this source,
- * provided that this copyright notice remains intact.
+ * Mini grep implementation for busybox using libc regex.
  *
- * The "grep" command, taken from sash.
- * This provides basic file searching.
+ * 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
  *
- * Permission to distribute this code under the GPL has been granted.
- * Modified for busybox by Erik Andersen <andersee@debian.org> <andersen@lineo.com>
  */
 
-#include "internal.h"
-#ifdef BB_GREP
-
 #include <stdio.h>
-#include <dirent.h>
+#include <stdlib.h>
+#include <getopt.h>
+#include <regex.h>
+#include <string.h> /* for strerror() */
 #include <errno.h>
-#include <fcntl.h>
-#include <signal.h>
-#include <time.h>
-#include <ctype.h>
-
-
-const char grep_usage[] =
-"Search the input file(s) for lines matching the given pattern.\n"
-"\tI search stdin if no files are given.\n"
-"\tI can't grok full regular expressions.\n"
-"usage: grep [in] PATTERN [FILES]...\n"
-"\ti=ignore case, n=list line numbers\n";
-
-
-
-static BOOL    search
-       (const char * string, const char * word, BOOL ignoreCase);
-
-
-extern int 
-grep_main(struct FileInfo * unused, int argc, char ** argv)
+#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 */
+
+/* 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)
 {
-       FILE *          fp;
-       const char *    word;
-       const char *    name;
-       const char *    cp;
-       BOOL            tellName;
-       BOOL            ignoreCase;
-       BOOL            tellLine;
-       long            line;
-       char            buf[BUF_SIZE];
-
-       ignoreCase = FALSE;
-       tellLine = FALSE;
-
-       argc--;
-       argv++;
-       if (argc < 1)
-       {
-               fprintf(stderr, "%s", grep_usage);
-               return 1;
-       }
-
-       if (**argv == '-')
-       {
-               argc--;
-               cp = *argv++;
-
-               while (*++cp) switch (*cp)
-               {
-                       case 'i':
-                               ignoreCase = TRUE;
-                               break;
-
-                       case 'n':
-                               tellLine = TRUE;
-                               break;
-
-                       default:
-                               fprintf(stderr, "Unknown option\n");
-                               return 1;
-               }
+#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);
+}
 
-       word = *argv++;
-       argc--;
-
-       tellName = (argc > 1);
-
-       while (argc-- > 0)
-       {
-               name = *argv++;
-
-               fp = fopen(name, "r");
-
-               if (fp == NULL)
-               {
-                       perror(name);
+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);
+                       }
 
-                       continue;
+                       /* 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, ':');
+                       }
                }
-
-               line = 0;
-
-               while (fgets(buf, sizeof(buf), fp))
-               {
-                       line++;
-
-                       cp = &buf[strlen(buf) - 1];
-
-                       if (*cp != '\n')
-                               fprintf(stderr, "%s: Line too long\n", name);
-
-                       if (search(buf, word, ignoreCase))
+#ifdef BB_FEATURE_GREP_CONTEXT
+               else { /* no match */
+                       /* Add the line to the circular 'before' buffer */
+                       if(lines_before)
                        {
-                               if (tellName)
-                                       printf("%s: ", name);
-
-                               if (tellLine)
-                                       printf("%ld: ", line);
-
-                               fputs(buf, stdout);
+                               if(before_buf[curpos])
+                                       free(before_buf[curpos]);
+                               before_buf[curpos] = strdup(line);
+                               curpos = (curpos + 1) % lines_before;
                        }
                }
 
-               if (ferror(fp))
-                       perror(name);
+               /* 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);
+       }
 
-               fclose(fp);
+       /* special-case post processing */
+       if (print_count_only) {
+               if (print_filename)
+                       printf("%s:", cur_file);
+               printf("%i\n", nmatches);
        }
-       return 0;
-}
 
+       /* remember if we matched */
+       if (nmatches != 0)
+               matched = 1;
+}
 
-/*
- * See if the specified word is found in the specified string.
- */
-static BOOL
-search(const char * string, const char * word, BOOL ignoreCase)
+extern int grep_main(int argc, char **argv)
 {
-       const char *    cp1;
-       const char *    cp2;
-       int             len;
-       int             lowFirst;
-       int             ch1;
-       int             ch2;
-
-       len = strlen(word);
-
-       if (!ignoreCase)
-       {
-               while (TRUE)
-               {
-                       string = strchr(string, word[0]);
-
-                       if (string == NULL)
-                               return FALSE;
-
-                       if (memcmp(string, word, len) == 0)
-                               return TRUE;
+       int opt;
+       int reflags;
+#ifdef BB_FEATURE_GREP_CONTEXT
+       char *junk;
+#endif
 
-                       string++;
+       /* 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;
+                       case 'v':
+                               invert_search++;
+                               break;
+                       case 's':
+                               suppress_err_msgs++;
+                               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 */
                }
        }
 
-       /*
-        * Here if we need to check case independence.
-        * Do the search by lower casing both strings.
-        */
-       lowFirst = *word;
-
-       if (isupper(lowFirst))
-               lowFirst = tolower(lowFirst);
-
-       while (TRUE)
-       {
-               while (*string && (*string != lowFirst) &&
-                       (!isupper(*string) || (tolower(*string) != lowFirst)))
-               {
-                       string++;
-               }
-
-               if (*string == '\0')
-                       return FALSE;
-
-               cp1 = string;
-               cp2 = word;
+       /* argv[optind] should be the regex pattern; no pattern, no worky */
+       if (argv[optind] == NULL)
+               show_usage();
 
-               do
-               {
-                       if (*cp2 == '\0')
-                               return TRUE;
-
-                       ch1 = *cp1++;
-
-                       if (isupper(ch1))
-                               ch1 = tolower(ch1);
-
-                       ch2 = *cp2++;
-
-                       if (isupper(ch2))
-                               ch2 = tolower(ch2);
+       /* 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);
+
+       /* 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++;
+
+       /* 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);
+                       }
                }
-               while (ch1 == ch2);
-
-               string++;
        }
-}
 
-#endif
-/* END CODE */
+       regfree(&regex);
+
+       return !matched; /* invert return value 0 = success, 1 = failed */
+}