commands/tar/subst.c

   1 /*-
   2  * Copyright (c) 2008 Joerg Sonnenberger
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
  15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  16  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  17  * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
  18  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  19  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  21  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  23  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #include "bsdtar_platform.h"
  27 __FBSDID("$FreeBSD: src/usr.bin/tar/subst.c,v 1.4 2008/06/15 10:08:16 kientzle Exp $");
  28
  29 #if HAVE_REGEX_H
  30 #include "bsdtar.h"
  31
  32 #include <errno.h>
  33 #include <regex.h>
  34 #include <stdlib.h>
  35 #include <string.h>
  36
  37 #ifndef REG_BASIC
  38 #define REG_BASIC 0
  39 #endif
  40
  41 #include "err.h"
  42
  43 struct subst_rule {
  44         struct subst_rule *next;
  45         regex_t re;
  46         char *result;
  47         unsigned int global:1, print:1, symlink:1;
  48 };
  49
  50 struct substitution {
  51         struct subst_rule *first_rule, *last_rule;
  52 };
  53
  54 static void
  55 init_substitution(struct bsdtar *bsdtar)
  56 {
  57         struct substitution *subst;
  58
  59         bsdtar->substitution = subst = malloc(sizeof(*subst));
  60         if (subst == NULL)
  61                 lafe_errc(1, errno, "Out of memory");
  62         subst->first_rule = subst->last_rule = NULL;
  63 }
  64
  65 void
  66 add_substitution(struct bsdtar *bsdtar, const char *rule_text)
  67 {
  68         struct subst_rule *rule;
  69         struct substitution *subst;
  70         const char *end_pattern, *start_subst;
  71         char *pattern;
  72         int r;
  73
  74         if ((subst = bsdtar->substitution) == NULL) {
  75                 init_substitution(bsdtar);
  76                 subst = bsdtar->substitution;
  77         }
  78
  79         rule = malloc(sizeof(*rule));
  80         if (rule == NULL)
  81                 lafe_errc(1, errno, "Out of memory");
  82         rule->next = NULL;
  83
  84         if (subst->last_rule == NULL)
  85                 subst->first_rule = rule;
  86         else
  87                 subst->last_rule->next = rule;
  88         subst->last_rule = rule;
  89
  90         if (*rule_text == '\0')
  91                 lafe_errc(1, 0, "Empty replacement string");
  92         end_pattern = strchr(rule_text + 1, *rule_text);
  93         if (end_pattern == NULL)
  94                 lafe_errc(1, 0, "Invalid replacement string");
  95
  96         pattern = malloc(end_pattern - rule_text);
  97         if (pattern == NULL)
  98                 lafe_errc(1, errno, "Out of memory");
  99         memcpy(pattern, rule_text + 1, end_pattern - rule_text - 1);
 100         pattern[end_pattern - rule_text - 1] = '\0';
 101
 102         if ((r = regcomp(&rule->re, pattern, REG_BASIC)) != 0) {
 103                 char buf[80];
 104                 regerror(r, &rule->re, buf, sizeof(buf));
 105                 lafe_errc(1, 0, "Invalid regular expression: %s", buf);
 106         }
 107         free(pattern);
 108
 109         start_subst = end_pattern + 1;
 110         end_pattern = strchr(start_subst, *rule_text);
 111         if (end_pattern == NULL)
 112                 lafe_errc(1, 0, "Invalid replacement string");
 113
 114         rule->result = malloc(end_pattern - start_subst + 1);
 115         if (rule->result == NULL)
 116                 lafe_errc(1, errno, "Out of memory");
 117         memcpy(rule->result, start_subst, end_pattern - start_subst);
 118         rule->result[end_pattern - start_subst] = '\0';
 119
 120         rule->global = 0;
 121         rule->print = 0;
 122         rule->symlink = 0;
 123
 124         while (*++end_pattern) {
 125                 switch (*end_pattern) {
 126                 case 'g':
 127                 case 'G':
 128                         rule->global = 1;
 129                         break;
 130                 case 'p':
 131                 case 'P':
 132                         rule->print = 1;
 133                         break;
 134                 case 's':
 135                 case 'S':
 136                         rule->symlink = 1;
 137                         break;
 138                 default:
 139                         lafe_errc(1, 0, "Invalid replacement flag %c", *end_pattern);
 140                 }
 141         }
 142 }
 143
 144 static void
 145 realloc_strncat(char **str, const char *append, size_t len)
 146 {
 147         char *new_str;
 148         size_t old_len;
 149
 150         if (*str == NULL)
 151                 old_len = 0;
 152         else
 153                 old_len = strlen(*str);
 154
 155         new_str = malloc(old_len + len + 1);
 156         if (new_str == NULL)
 157                 lafe_errc(1, errno, "Out of memory");
 158         memcpy(new_str, *str, old_len);
 159         memcpy(new_str + old_len, append, len);
 160         new_str[old_len + len] = '\0';
 161         free(*str);
 162         *str = new_str;
 163 }
 164
 165 static void
 166 realloc_strcat(char **str, const char *append)
 167 {
 168         char *new_str;
 169         size_t old_len;
 170
 171         if (*str == NULL)
 172                 old_len = 0;
 173         else
 174                 old_len = strlen(*str);
 175
 176         new_str = malloc(old_len + strlen(append) + 1);
 177         if (new_str == NULL)
 178                 lafe_errc(1, errno, "Out of memory");
 179         memcpy(new_str, *str, old_len);
 180         strcpy(new_str + old_len, append);
 181         free(*str);
 182         *str = new_str;
 183 }
 184
 185 int
 186 apply_substitution(struct bsdtar *bsdtar, const char *name, char **result, int symlink_only)
 187 {
 188         const char *path = name;
 189         regmatch_t matches[10];
 190         size_t i, j;
 191         struct subst_rule *rule;
 192         struct substitution *subst;
 193         int c, got_match, print_match;
 194
 195         *result = NULL;
 196
 197         if ((subst = bsdtar->substitution) == NULL)
 198                 return 0;
 199
 200         got_match = 0;
 201         print_match = 0;
 202
 203         for (rule = subst->first_rule; rule != NULL; rule = rule->next) {
 204                 if (symlink_only && !rule->symlink)
 205                         continue;
 206                 if (regexec(&rule->re, name, 10, matches, 0))
 207                         continue;
 208
 209                 got_match = 1;
 210                 print_match |= rule->print;
 211                 realloc_strncat(result, name, matches[0].rm_so);
 212
 213                 for (i = 0, j = 0; rule->result[i] != '\0'; ++i) {
 214                         if (rule->result[i] == '~') {
 215                                 realloc_strncat(result, rule->result + j, i - j);
 216                                 realloc_strncat(result, name, matches[0].rm_eo);
 217                                 j = i + 1;
 218                                 continue;
 219                         }
 220                         if (rule->result[i] != '\\')
 221                                 continue;
 222
 223                         ++i;
 224                         c = rule->result[i];
 225                         switch (c) {
 226                         case '~':
 227                         case '\\':
 228                                 realloc_strncat(result, rule->result + j, i - j - 1);
 229                                 j = i;
 230                                 break;
 231                         case '1':
 232                         case '2':
 233                         case '3':
 234                         case '4':
 235                         case '5':
 236                         case '6':
 237                         case '7':
 238                         case '8':
 239                         case '9':
 240                                 realloc_strncat(result, rule->result + j, i - j - 1);
 241                                 if ((size_t)(c - '0') > (size_t)(rule->re.re_nsub)) {
 242                                         free(*result);
 243                                         *result = NULL;
 244                                         return -1;
 245                                 }
 246                                 realloc_strncat(result, name + matches[c - '0'].rm_so, matches[c - '0'].rm_eo - matches[c - '0'].rm_so);
 247                                 j = i + 1;
 248                                 break;
 249                         default:
 250                                 /* Just continue; */
 251                                 break;
 252                         }
 253
 254                 }
 255
 256                 realloc_strcat(result, rule->result + j);
 257
 258                 name += matches[0].rm_eo;
 259
 260                 if (!rule->global)
 261                         break;
 262         }
 263
 264         if (got_match)
 265                 realloc_strcat(result, name);
 266
 267         if (print_match)
 268                 fprintf(stderr, "%s >> %s\n", path, *result);
 269
 270         return got_match;
 271 }
 272
 273 void
 274 cleanup_substitution(struct bsdtar *bsdtar)
 275 {
 276         struct subst_rule *rule;
 277         struct substitution *subst;
 278
 279         if ((subst = bsdtar->substitution) == NULL)
 280                 return;
 281
 282         while ((rule = subst->first_rule) != NULL) {
 283                 subst->first_rule = rule->next;
 284                 free(rule->result);
 285                 free(rule);
 286         }
 287         free(subst);
 288 }
 289 #endif /* HAVE_REGEX_H */