mdw@git.distorted.org.uk Git - dpkg/blob - src/divertdb.c

   1 /*
   2  * dpkg - main program for package management
   3  * divertdb.c - management of database of diverted files
   4  *
   5  * Copyright © 1995 Ian Jackson <ijackson@chiark.greenend.org.uk>
   6  * Copyright © 2000, 2001 Wichert Akkerman <wakkerma@debian.org>
   7  *
   8  * This is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  20  */
  21
  22 #include <config.h>
  23 #include <compat.h>
  24
  25 #include <sys/types.h>
  26 #include <sys/stat.h>
  27
  28 #include <errno.h>
  29 #include <string.h>
  30 #include <pwd.h>
  31 #include <grp.h>
  32 #include <fcntl.h>
  33 #include <unistd.h>
  34 #include <stdlib.h>
  35
  36 #include <dpkg/i18n.h>
  37 #include <dpkg/dpkg.h>
  38 #include <dpkg/dpkg-db.h>
  39
  40 #include "filesdb.h"
  41 #include "main.h"
  42
  43 static struct diversion *diversions = NULL;
  44 static char *diversionsname;
  45
  46 void
  47 ensure_diversions(void)
  48 {
  49         static struct stat sb_prev;
  50         struct stat sb_next;
  51         char linebuf[MAXDIVERTFILENAME];
  52         static FILE *file_prev;
  53         FILE *file;
  54         struct diversion *ov, *oicontest, *oialtname;
  55
  56         if (diversionsname == NULL)
  57                 diversionsname = dpkg_db_get_path(DIVERSIONSFILE);
  58
  59         onerr_abort++;
  60
  61         file = fopen(diversionsname, "r");
  62         if (!file) {
  63                 if (errno != ENOENT)
  64                         ohshite(_("failed to open diversions file"));
  65         } else {
  66                 setcloexec(fileno(file), diversionsname);
  67
  68                 if (fstat(fileno(file), &sb_next))
  69                         ohshite(_("failed to fstat diversions file"));
  70
  71                 /*
  72                  * We need to keep the database file open so that the
  73                  * filesystem cannot reuse the inode number (f.ex. during
  74                  * multiple dpkg-divert invocations in a maintainer script),
  75                  * otherwise the following check might turn true, and we
  76                  * would skip reloading a modified database.
  77                  */
  78                 if (file_prev &&
  79                     sb_prev.st_dev == sb_next.st_dev &&
  80                     sb_prev.st_ino == sb_next.st_ino) {
  81                         fclose(file);
  82                         onerr_abort--;
  83                         debug(dbg_general, "%s: same, skipping", __func__);
  84                         return;
  85                 }
  86                 sb_prev = sb_next;
  87         }
  88         if (file_prev)
  89                 fclose(file_prev);
  90         file_prev = file;
  91
  92         for (ov = diversions; ov; ov = ov->next) {
  93                 ov->useinstead->divert->camefrom->divert = NULL;
  94                 ov->useinstead->divert = NULL;
  95         }
  96         diversions = NULL;
  97         if (!file) {
  98                 onerr_abort--;
  99                 debug(dbg_general, "%s: none, resetting", __func__);
 100                 return;
 101         }
 102         debug(dbg_general, "%s: new, (re)loading", __func__);
 103
 104         while (fgets_checked(linebuf, sizeof(linebuf), file, diversionsname) >= 0) {
 105                 oicontest = nfmalloc(sizeof(struct diversion));
 106                 oialtname = nfmalloc(sizeof(struct diversion));
 107
 108                 oialtname->camefrom = findnamenode(linebuf, 0);
 109                 oialtname->useinstead = NULL;
 110
 111                 fgets_must(linebuf, sizeof(linebuf), file, diversionsname);
 112                 oicontest->useinstead = findnamenode(linebuf, 0);
 113                 oicontest->camefrom = NULL;
 114
 115                 fgets_must(linebuf, sizeof(linebuf), file, diversionsname);
 116                 oicontest->pkgset = strcmp(linebuf, ":") ?
 117                                     pkg_db_find_set(linebuf) : NULL;
 118                 oialtname->pkgset = oicontest->pkgset;
 119
 120                 if (oialtname->camefrom->divert ||
 121                     oicontest->useinstead->divert)
 122                         ohshit(_("conflicting diversions involving '%.250s' or '%.250s'"),
 123                                oialtname->camefrom->name, oicontest->useinstead->name);
 124
 125                 oialtname->camefrom->divert = oicontest;
 126                 oicontest->useinstead->divert = oialtname;
 127
 128                 oicontest->next = diversions;
 129                 diversions = oicontest;
 130         }
 131
 132         onerr_abort--;
 133 }