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   1 /*
   2  * wildcard.c
   3  *
   4  * Wildcard matching functions.
   5  */
   6
   7 /*
   8  * Copyright (C) 2013 Eric Biggers
   9  *
  10  * This file is part of wimlib, a library for working with WIM files.
  11  *
  12  * wimlib is free software; you can redistribute it and/or modify it under the
  13  * terms of the GNU General Public License as published by the Free
  14  * Software Foundation; either version 3 of the License, or (at your option)
  15  * any later version.
  16  *
  17  * wimlib is distributed in the hope that it will be useful, but WITHOUT ANY
  18  * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
  19  * A PARTICULAR PURPOSE. See the GNU General Public License for more
  20  * details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with wimlib; if not, see http://www.gnu.org/licenses/.
  24  */
  25
  26 #ifdef HAVE_CONFIG_H
  27 #  include "config.h"
  28 #endif
  29
  30 #include <ctype.h>
  31 #include "wimlib/dentry.h"
  32 #include "wimlib/encoding.h"
  33 #include "wimlib/error.h"
  34 #include "wimlib/metadata.h"
  35 #include "wimlib/paths.h"
  36 #include "wimlib/wildcard.h"
  37
  38 struct match_dentry_ctx {
  39         int (*consume_dentry)(struct wim_dentry *, void *);
  40         void *consume_dentry_ctx;
  41         size_t consume_dentry_count;
  42         tchar *wildcard_path;
  43         size_t cur_component_offset;
  44         size_t cur_component_len;
  45         bool case_insensitive;
  46 };
  47
  48 static bool
  49 do_match_wildcard(const tchar *string, size_t string_len,
  50                   const tchar *wildcard, size_t wildcard_len,
  51                   bool ignore_case)
  52 {
  53         for (;;) {
  54                 if (string_len == 0) {
  55                         while (wildcard_len != 0 && *wildcard == T('*')) {
  56                                 wildcard++;
  57                                 wildcard_len--;
  58                         }
  59                         return (wildcard_len == 0);
  60                 } else if (wildcard_len == 0) {
  61                         return false;
  62                 } else if (*string == *wildcard || *wildcard == T('?') ||
  63                            (ignore_case && totlower(*string) == totlower(*wildcard)))
  64                 {
  65                         string++;
  66                         string_len--;
  67                         wildcard_len--;
  68                         wildcard++;
  69                         continue;
  70                 } else if (*wildcard == T('*')) {
  71                         return do_match_wildcard(string, string_len,
  72                                                  wildcard + 1, wildcard_len - 1,
  73                                                  ignore_case) ||
  74                                do_match_wildcard(string + 1, string_len - 1,
  75                                                  wildcard, wildcard_len,
  76                                                  ignore_case);
  77                 } else {
  78                         return false;
  79                 }
  80         }
  81 }
  82
  83 static bool
  84 match_wildcard(const tchar *string, const tchar *wildcard,
  85                size_t wildcard_len, bool ignore_case)
  86 {
  87         return do_match_wildcard(string, tstrlen(string),
  88                                  wildcard, wildcard_len, ignore_case);
  89 }
  90
  91 /*
  92  * Determines whether a path matches a wildcard pattern.
  93  *
  94  * @path
  95  *      The path to match.  Assumptions:  All path separators must be @path_sep,
  96  *      there cannot be consecutive path separators, there cannot be a trailing
  97  *      path separator, and there must be exactly one leading path separator.
  98  *
  99  * @path_nchars
 100  *      Number of characters in @path.
 101  *
 102  * @wildcard
 103  *      The wildcard pattern to match.  It can contain the wildcard characters
 104  *      '*' and '?'.  The former matches zero or more characters except
 105  *      @path_sep, and the latter matches any character except @path_sep.  All
 106  *      path separators in the pattern must be @path_sep, and there cannot be
 107  *      consecutive path separators, and there cannot be a trailing path
 108  *      separator.  If there is a leading path separator, the match is attempted
 109  *      with the filename only; otherwise, the matchis attempted with the whole
 110  *      path.
 111  *
 112  * @path_sep
 113  *      Path separator character in @path and @wildcard.
 114  *
 115  * @prefix_ok
 116  *      If %true, allow a prefix of @path, terminated by a path separator, to
 117  *      match, in addition to @path itself.  a.k.a. also return true if the
 118  *      wildcard actually matches one of the ancestor directories of @path.
 119  *
 120  * Returns %true if there was a match; %false if there was not.
 121  */
 122 bool
 123 match_path(const tchar *path, size_t path_nchars,
 124            const tchar *wildcard, tchar path_sep, bool prefix_ok)
 125 {
 126         if (*wildcard != path_sep) {
 127                 /* Pattern doesn't begin with path separator.  Try to match the
 128                  * file name only.  */
 129                 return match_wildcard(path_basename_with_len(path, path_nchars),
 130                                       wildcard, tstrlen(wildcard),
 131                                       default_ignore_case);
 132         } else {
 133                 /* Pattern begins with path separator.  Try to match the whole
 134                  * path.  */
 135                 do {
 136                         if (!*wildcard) {
 137                                 /* Path has more components than pattern  */
 138                                 return prefix_ok;
 139                         }
 140
 141                         size_t path_component_len = 0;
 142                         size_t wildcard_component_len = 0;
 143
 144                         do {
 145                                 path_component_len++;
 146                         } while (path[path_component_len] != path_sep &&
 147                                  path[path_component_len] != T('\0'));
 148                         do {
 149                                 wildcard_component_len++;
 150                         } while (wildcard[wildcard_component_len] != path_sep &&
 151                                  wildcard[wildcard_component_len] != T('\0'));
 152                         if (!do_match_wildcard(path, path_component_len,
 153                                                wildcard, wildcard_component_len,
 154                                                default_ignore_case))
 155                                 return false;
 156                         path += path_component_len;
 157                         wildcard += wildcard_component_len;
 158                 } while (*path);
 159
 160                 return (*wildcard == '\0');
 161         }
 162 }
 163
 164 static int
 165 expand_wildcard_recursive(struct wim_dentry *cur_dentry,
 166                           struct match_dentry_ctx *ctx);
 167
 168 enum {
 169         WILDCARD_STATUS_DONE_FULLY,
 170         WILDCARD_STATUS_DONE_TRAILING_SLASHES,
 171         WILDCARD_STATUS_NOT_DONE,
 172 };
 173
 174 static int
 175 wildcard_status(const tchar *wildcard)
 176 {
 177         if (*wildcard == T('\0'))
 178                 return WILDCARD_STATUS_DONE_FULLY;
 179         while (*wildcard == WIM_PATH_SEPARATOR)
 180                 wildcard++;
 181         if (*wildcard == T('\0'))
 182                 return WILDCARD_STATUS_DONE_TRAILING_SLASHES;
 183
 184         return WILDCARD_STATUS_NOT_DONE;
 185 }
 186
 187 static int
 188 match_dentry(struct wim_dentry *cur_dentry, struct match_dentry_ctx *ctx)
 189 {
 190         tchar *name;
 191         size_t name_len;
 192         int ret;
 193
 194         if (cur_dentry->file_name_nbytes == 0)
 195                 return 0;
 196
 197 #if TCHAR_IS_UTF16LE
 198         name = cur_dentry->file_name;
 199         name_len = cur_dentry->file_name_nbytes;
 200 #else
 201         ret = utf16le_to_tstr(cur_dentry->file_name,
 202                               cur_dentry->file_name_nbytes,
 203                               &name, &name_len);
 204         if (ret)
 205                 return ret;
 206 #endif
 207         name_len /= sizeof(tchar);
 208
 209         if (match_wildcard(name,
 210                            &ctx->wildcard_path[ctx->cur_component_offset],
 211                            ctx->cur_component_len,
 212                            ctx->case_insensitive))
 213         {
 214                 switch (wildcard_status(&ctx->wildcard_path[
 215                                 ctx->cur_component_offset +
 216                                 ctx->cur_component_len]))
 217                 {
 218                 case WILDCARD_STATUS_DONE_TRAILING_SLASHES:
 219                         if (!dentry_is_directory(cur_dentry)) {
 220                                 ret = 0;
 221                                 break;
 222                         }
 223                         /* Fall through  */
 224                 case WILDCARD_STATUS_DONE_FULLY:
 225                         ret = (*ctx->consume_dentry)(cur_dentry,
 226                                                      ctx->consume_dentry_ctx);
 227                         ctx->consume_dentry_count++;
 228                         break;
 229                 case WILDCARD_STATUS_NOT_DONE:
 230                         ret = expand_wildcard_recursive(cur_dentry, ctx);
 231                         break;
 232                 }
 233         } else {
 234                 ret = 0;
 235         }
 236
 237 #if !TCHAR_IS_UTF16LE
 238         FREE(name);
 239 #endif
 240         return ret;
 241 }
 242
 243 static int
 244 expand_wildcard_recursive(struct wim_dentry *cur_dentry,
 245                           struct match_dentry_ctx *ctx)
 246 {
 247         tchar *w;
 248         size_t begin;
 249         size_t end;
 250         size_t len;
 251         size_t offset_save;
 252         size_t len_save;
 253         int ret;
 254         struct wim_dentry *child;
 255
 256         w = ctx->wildcard_path;
 257
 258         begin = ctx->cur_component_offset + ctx->cur_component_len;
 259         while (w[begin] == WIM_PATH_SEPARATOR)
 260                 begin++;
 261
 262         end = begin;
 263
 264         while (w[end] != T('\0') && w[end] != WIM_PATH_SEPARATOR)
 265                 end++;
 266
 267         len = end - begin;
 268
 269         if (len == 0)
 270                 return 0;
 271
 272         offset_save = ctx->cur_component_offset;
 273         len_save = ctx->cur_component_len;
 274
 275         ctx->cur_component_offset = begin;
 276         ctx->cur_component_len = len;
 277
 278         ret = 0;
 279         for_dentry_child(child, cur_dentry) {
 280                 ret = match_dentry(child, ctx);
 281                 if (ret)
 282                         break;
 283         }
 284
 285         ctx->cur_component_len = len_save;
 286         ctx->cur_component_offset = offset_save;
 287
 288         return ret;
 289 }
 290
 291 /* Expand a wildcard relative to the current WIM image.
 292  *
 293  * @wim
 294  *      WIMStruct whose currently selected image is searched to expand the
 295  *      wildcard.
 296  * @wildcard_path
 297  *      Wildcard path to expand, which may contain the '?' and '*' characters.
 298  *      Path separators must be WIM_PATH_SEPARATOR.  Leading path separators are
 299  *      ignored, whereas one or more trailing path separators indicate that the
 300  *      wildcard path can only match directories (and not reparse points).
 301  * @consume_dentry
 302  *      Callback function which will receive each directory entry matched by the
 303  *      wildcard.
 304  * @consume_dentry_ctx
 305  *      Argument to pass to @consume_dentry.
 306  * @flags
 307  *      Zero or more of the following flags:
 308  *
 309  *      WILDCARD_FLAG_WARN_IF_NO_MATCH:
 310  *              Issue a warning if the wildcard does not match any dentries.
 311  *
 312  *      WILDCARD_FLAG_ERROR_IF_NO_MATCH:
 313  *              Issue an error and return WIMLIB_ERR_PATH_DOES_NOT_EXIST if the
 314  *              wildcard does not match any dentries.
 315  *
 316  *      WILDCARD_FLAG_CASE_INSENSITIVE:
 317  *              Perform the matching case insensitively.  Note that this may
 318  *              cause @wildcard to match multiple dentries, even if it does not
 319  *              contain wildcard characters.
 320  *
 321  * @return 0 on success; a positive error code on error; or the first nonzero
 322  * value returned by @consume_dentry.
 323  */
 324 int
 325 expand_wildcard(WIMStruct *wim,
 326                 const tchar *wildcard_path,
 327                 int (*consume_dentry)(struct wim_dentry *, void *),
 328                 void *consume_dentry_ctx,
 329                 u32 flags)
 330 {
 331         struct wim_dentry *root;
 332         int ret;
 333
 334         root = wim_root_dentry(wim);
 335         if (root == NULL)
 336                 goto no_match;
 337
 338         struct match_dentry_ctx ctx = {
 339                 .consume_dentry = consume_dentry,
 340                 .consume_dentry_ctx = consume_dentry_ctx,
 341                 .consume_dentry_count = 0,
 342                 .wildcard_path = TSTRDUP(wildcard_path),
 343                 .cur_component_offset = 0,
 344                 .cur_component_len = 0,
 345                 .case_insensitive = ((flags & WILDCARD_FLAG_CASE_INSENSITIVE) != 0),
 346         };
 347
 348         if (ctx.wildcard_path == NULL)
 349                 return WIMLIB_ERR_NOMEM;
 350
 351         ret = expand_wildcard_recursive(root, &ctx);
 352         FREE(ctx.wildcard_path);
 353         if (ret == 0 && ctx.consume_dentry_count == 0)
 354                 goto no_match;
 355         return ret;
 356
 357 no_match:
 358         ret = 0;
 359         if (flags & WILDCARD_FLAG_WARN_IF_NO_MATCH)
 360                 WARNING("No matches for wildcard path \"%"TS"\"", wildcard_path);
 361
 362         if (flags & WILDCARD_FLAG_ERROR_IF_NO_MATCH) {
 363                 ERROR("No matches for wildcard path \"%"TS"\"", wildcard_path);
 364                 ret = WIMLIB_ERR_PATH_DOES_NOT_EXIST;
 365         }
 366         return ret;
 367 }