lib/dpkg/fsys.h

   1 /*
   2  * libdpkg - Debian packaging suite library routines
   3  * fsys.h - filesystem nodes hash table
   4  *
   5  * Copyright © 1995 Ian Jackson <ijackson@chiark.greenend.org.uk>
   6  * Copyright © 2008-2014 Guillem Jover <guillem@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 #ifndef LIBDPKG_FSYS_H
  23 #define LIBDPKG_FSYS_H
  24
  25 #include <stdio.h>
  26
  27 #include <dpkg/file.h>
  28
  29 DPKG_BEGIN_DECLS
  30
  31 /*
  32  * Data structure here is as follows:
  33  *
  34  * For each package we have a ‘struct fsys_namenode_list *’, the head of a list of
  35  * files in that package. They are in ‘forwards’ order. Each entry has a
  36  * pointer to the ‘struct fsys_namenode’.
  37  *
  38  * The struct fsys_namenodes are in a hash table, indexed by name.
  39  * (This hash table is not visible to callers.)
  40  *
  41  * Each fsys_namenode has a (possibly empty) list of ‘struct filepackage’,
  42  * giving a list of the packages listing that filename.
  43  *
  44  * When we read files contained info about a particular package we set the
  45  * ‘files’ member of the clientdata struct to the appropriate thing. When
  46  * not yet set the files pointer is made to point to ‘fileslist_uninited’
  47  * (this is available only internally, within filesdb.c - the published
  48  * interface is ensure_*_available).
  49  */
  50
  51 struct pkginfo;
  52
  53 /**
  54  * Flags to fsys_hash_find_node().
  55  */
  56 enum DPKG_ATTR_ENUM_FLAGS fsys_hash_find_flags {
  57         /** No flags. */
  58         FHFF_NONE                       = 0,
  59         /** Do not need to copy filename. */
  60         FHFF_NOCOPY                     = DPKG_BIT(0),
  61         /** Do not insert the item if it is not found, and return NULL. */
  62         FHFF_NONEW                      = DPKG_BIT(1),
  63 };
  64
  65 enum DPKG_ATTR_ENUM_FLAGS fsys_namenode_flags {
  66         /** No flags. */
  67         FNNF_NONE                       = 0,
  68         /** In the newconffiles list. */
  69         FNNF_NEW_CONFF                  = DPKG_BIT(0),
  70         /** In the new filesystem archive. */
  71         FNNF_NEW_INARCHIVE              = DPKG_BIT(1),
  72         /** In the old package's conffiles list. */
  73         FNNF_OLD_CONFF                  = DPKG_BIT(2),
  74         /** Obsolete conffile. */
  75         FNNF_OBS_CONFF                  = DPKG_BIT(3),
  76         /** Must remove from other packages' lists. */
  77         FNNF_ELIDE_OTHER_LISTS          = DPKG_BIT(4),
  78         /** >= 1 instance is a dir, cannot rename over. */
  79         FNNF_NO_ATOMIC_OVERWRITE        = DPKG_BIT(5),
  80         /** New file has been placed on the disk. */
  81         FNNF_PLACED_ON_DISK             = DPKG_BIT(6),
  82         FNNF_DEFERRED_FSYNC             = DPKG_BIT(7),
  83         FNNF_DEFERRED_RENAME            = DPKG_BIT(8),
  84         /** Path being filtered. */
  85         FNNF_FILTERED                   = DPKG_BIT(9),
  86         /** Conffile removal requested by upgrade. */
  87         FNNF_RM_CONFF_ON_UPGRADE        = DPKG_BIT(10),
  88 };
  89
  90 /**
  91  * Stores information to uniquely identify an on-disk file.
  92  */
  93 struct file_ondisk_id {
  94         dev_t id_dev;
  95         ino_t id_ino;
  96 };
  97
  98 struct fsys_namenode {
  99         struct fsys_namenode *next;
 100         const char *name;
 101         struct pkg_list *packages;
 102         struct fsys_diversion *divert;
 103
 104         /** We allow the administrator to override the owner, group and mode
 105          * of a file. If such an override is present we use that instead of
 106          * the stat information stored in the archive.
 107          *
 108          * This functionality used to be in the suidmanager package. */
 109         struct file_stat *statoverride;
 110
 111         struct trigfileint *trig_interested;
 112
 113         /*
 114          * Fields from here on are used by archives.c &c, and cleared by
 115          * fsys_hash_init().
 116          */
 117
 118         /** Set to zero when a new node is created. */
 119         enum fsys_namenode_flags flags;
 120
 121         /** Valid iff this namenode is in the newconffiles list. */
 122         const char *oldhash;
 123
 124         /** Valid iff the file was unpacked and hashed on this run. */
 125         const char *newhash;
 126
 127         struct file_ondisk_id *file_ondisk_id;
 128 };
 129
 130 struct fsys_namenode_list {
 131         struct fsys_namenode_list *next;
 132         struct fsys_namenode *namenode;
 133 };
 134
 135 /**
 136  * Queue of fsys_namenode entries.
 137  */
 138 struct fsys_namenode_queue {
 139         struct fsys_namenode_list *head, **tail;
 140 };
 141
 142 /**
 143  * When we deal with an ‘overridden’ file, every package except the
 144  * overriding one is considered to contain the other file instead. Both
 145  * files have entries in the filesdb database, and they refer to each other
 146  * via these diversion structures.
 147  *
 148  * The contested filename's fsys_namenode has a diversion entry with
 149  * useinstead set to point to the redirected filename's fsys_namenode; the
 150  * redirected fsys_namenode has camefrom set to the contested fsys_namenode.
 151  * Both sides' diversion entries will have pkg set to the package (if any)
 152  * which is allowed to use the contended filename.
 153  *
 154  * Packages that contain either version of the file will all refer to the
 155  * contested fsys_namenode in their per-file package lists (both in core and
 156  * on disk). References are redirected to the other fsys_namenode's filename
 157  * where appropriate.
 158  */
 159 struct fsys_diversion {
 160         struct fsys_namenode *useinstead;
 161         struct fsys_namenode *camefrom;
 162         struct pkgset *pkgset;
 163
 164         /** The ‘contested’ halves are in this list for easy cleanup. */
 165         struct fsys_diversion *next;
 166 };
 167
 168 struct fsys_node_pkgs_iter;
 169 struct fsys_node_pkgs_iter *
 170 fsys_node_pkgs_iter_new(struct fsys_namenode *fnn);
 171 struct pkginfo *
 172 fsys_node_pkgs_iter_next(struct fsys_node_pkgs_iter *iter);
 173 void
 174 fsys_node_pkgs_iter_free(struct fsys_node_pkgs_iter *iter);
 175
 176 void
 177 fsys_hash_init(void);
 178 void
 179 fsys_hash_reset(void);
 180 void
 181 fsys_hash_report(FILE *file);
 182 int
 183 fsys_hash_entries(void);
 184
 185 struct fsys_hash_iter;
 186 struct fsys_hash_iter *
 187 fsys_hash_iter_new(void);
 188 struct fsys_namenode *
 189 fsys_hash_iter_next(struct fsys_hash_iter *iter);
 190 void
 191 fsys_hash_iter_free(struct fsys_hash_iter *iter);
 192
 193 struct fsys_namenode *
 194 fsys_hash_find_node(const char *filename, enum fsys_hash_find_flags flags);
 195
 196 struct fsys_hash_rev_iter {
 197         struct fsys_namenode_list *todo;
 198 };
 199
 200 void
 201 fsys_hash_rev_iter_init(struct fsys_hash_rev_iter *iter,
 202                         struct fsys_namenode_list *files);
 203 struct fsys_namenode *
 204 fsys_hash_rev_iter_next(struct fsys_hash_rev_iter *iter);
 205 void
 206 fsys_hash_rev_iter_abort(struct fsys_hash_rev_iter *iter);
 207
 208 const char *dpkg_fsys_set_dir(const char *dir);
 209 const char *dpkg_fsys_get_dir(void);
 210 char *dpkg_fsys_get_path(const char *pathpart);
 211
 212 DPKG_END_DECLS
 213
 214 #endif /* LIBDPKG_FSYS_H */