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       1                 :            : /*
       2                 :            :  * dpkg - main program for package management
       3                 :            :  * filters.c - filtering routines for excluding bits of packages
       4                 :            :  *
       5                 :            :  * Copyright © 2007, 2008 Tollef Fog Heen <tfheen@err.no>
       6                 :            :  * Copyright © 2008, 2010, 2012-2014 Guillem Jover <guillem@debian.org>
       7                 :            :  * Copyright © 2010 Canonical Ltd.
       8                 :            :  *   written by Martin Pitt <martin.pitt@canonical.com>
       9                 :            :  *
      10                 :            :  * This is free software; you can redistribute it and/or modify
      11                 :            :  * it under the terms of the GNU General Public License as published by
      12                 :            :  * the Free Software Foundation; either version 2 of the License, or
      13                 :            :  * (at your option) any later version.
      14                 :            :  *
      15                 :            :  * This is distributed in the hope that it will be useful,
      16                 :            :  * but WITHOUT ANY WARRANTY; without even the implied warranty of
      17                 :            :  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      18                 :            :  * GNU General Public License for more details.
      19                 :            :  *
      20                 :            :  * You should have received a copy of the GNU General Public License
      21                 :            :  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
      22                 :            :  */
      23                 :            : 
      24                 :            : #include <config.h>
      25                 :            : #include <compat.h>
      26                 :            : 
      27                 :            : #include <fnmatch.h>
      28                 :            : 
      29                 :            : #include <dpkg/i18n.h>
      30                 :            : #include <dpkg/dpkg.h>
      31                 :            : #include <dpkg/dpkg-db.h>
      32                 :            : #include <dpkg/db-fsys.h>
      33                 :            : 
      34                 :            : #include "main.h"
      35                 :            : #include "filters.h"
      36                 :            : 
      37                 :            : struct filter_node {
      38                 :            :         struct filter_node *next;
      39                 :            :         char *pattern;
      40                 :            :         bool include;
      41                 :            : };
      42                 :            : 
      43                 :            : static struct filter_node *filter_head = NULL;
      44                 :            : static struct filter_node **filter_tail = &filter_head;
      45                 :            : 
      46                 :            : void
      47                 :          0 : filter_add(const char *pattern, bool include)
      48                 :            : {
      49                 :            :         struct filter_node *filter;
      50                 :            : 
      51         [ #  # ]:          0 :         debug(dbg_general, "adding %s filter for '%s'",
      52                 :            :               include ? "include" : "exclude", pattern);
      53                 :            : 
      54                 :          0 :         filter = m_malloc(sizeof(*filter));
      55                 :          0 :         filter->pattern = m_strdup(pattern);
      56                 :          0 :         filter->include = include;
      57                 :          0 :         filter->next = NULL;
      58                 :            : 
      59                 :          0 :         *filter_tail = filter;
      60                 :          0 :         filter_tail = &filter->next;
      61                 :          0 : }
      62                 :            : 
      63                 :            : bool
      64                 :          0 : filter_should_skip(struct tar_entry *ti)
      65                 :            : {
      66                 :            :         struct filter_node *f;
      67                 :          0 :         bool skip = false;
      68                 :            : 
      69         [ #  # ]:          0 :         if (!filter_head)
      70                 :          0 :                 return false;
      71                 :            : 
      72                 :            :         /* Last match wins. */
      73         [ #  # ]:          0 :         for (f = filter_head; f != NULL; f = f->next) {
      74                 :          0 :                 debug(dbg_eachfile, "filter comparing '%s' and '%s'",
      75                 :          0 :                       &ti->name[1], f->pattern);
      76                 :            : 
      77         [ #  # ]:          0 :                 if (fnmatch(f->pattern, &ti->name[1], 0) == 0) {
      78         [ #  # ]:          0 :                         if (f->include) {
      79                 :          0 :                                 skip = false;
      80                 :          0 :                                 debug(dbg_eachfile, "filter including %s",
      81                 :            :                                       ti->name);
      82                 :            :                         } else {
      83                 :          0 :                                 skip = true;
      84                 :          0 :                                 debug(dbg_eachfile, "filter removing %s",
      85                 :            :                                       ti->name);
      86                 :            :                         }
      87                 :            :                 }
      88                 :            :         }
      89                 :            : 
      90                 :            :         /* We need to keep directories (or symlinks to directories) if a
      91                 :            :          * glob excludes them, but a more specific include glob brings back
      92                 :            :          * files; XXX the current implementation will probably include more
      93                 :            :          * directories than necessary, but better err on the side of caution
      94                 :            :          * than failing with “no such file or directory” (which would leave
      95                 :            :          * the package in a very bad state). */
      96   [ #  #  #  # ]:          0 :         if (skip && (ti->type == TAR_FILETYPE_DIR ||
      97         [ #  # ]:          0 :                      ti->type == TAR_FILETYPE_SYMLINK)) {
      98                 :          0 :                 debug(dbg_eachfile,
      99                 :            :                       "filter seeing if '%s' needs to be reincluded",
     100                 :          0 :                       &ti->name[1]);
     101                 :            : 
     102         [ #  # ]:          0 :                 for (f = filter_head; f != NULL; f = f->next) {
     103                 :            :                         const char *wildcard;
     104                 :            :                         int path_len;
     105                 :            : 
     106         [ #  # ]:          0 :                         if (!f->include)
     107                 :          0 :                                 continue;
     108                 :            : 
     109                 :            :                         /* Calculate the offset of the first wildcard
     110                 :            :                          * character in the pattern. */
     111                 :          0 :                         wildcard = strpbrk(f->pattern, "*?[\\");
     112         [ #  # ]:          0 :                         if (wildcard)
     113                 :          0 :                                 path_len = wildcard - f->pattern;
     114                 :            :                         else
     115                 :          0 :                                 path_len = strlen(f->pattern);
     116                 :            : 
     117                 :            :                         /* Ignore any trailing slash for the comparison. */
     118   [ #  #  #  # ]:          0 :                         while (path_len && f->pattern[path_len - 1] == '/')
     119                 :          0 :                                 path_len--;
     120                 :            : 
     121                 :          0 :                         debug(dbg_eachfiledetail,
     122                 :            :                               "filter subpattern '%.*s'", path_len, f->pattern);
     123                 :            : 
     124         [ #  # ]:          0 :                         if (strncmp(&ti->name[1], f->pattern, path_len) == 0) {
     125                 :          0 :                                 debug(dbg_eachfile, "filter reincluding %s",
     126                 :            :                                       ti->name);
     127                 :          0 :                                 return false;
     128                 :            :                         }
     129                 :            :                 }
     130                 :            :         }
     131                 :            : 
     132                 :          0 :         return skip;
     133                 :            : }