lib/dpkg/fsys-dir.c

   1 /*
   2  * libdpkg - Debian packaging suite library routines
   3  * fsys-dir.c - filesystem root directory functions
   4  *
   5  * Copyright © 2011, 2018 Guillem Jover <guillem@debian.org>
   6  *
   7  * This is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  19  */
  20
  21 #include <config.h>
  22 #include <compat.h>
  23
  24 #include <stdlib.h>
  25
  26 #include <dpkg/dpkg.h>
  27 #include <dpkg/string.h>
  28 #include <dpkg/path.h>
  29 #include <dpkg/fsys.h>
  30
  31 static char *fsys_dir;
  32
  33 /**
  34  * Allocate the default on-disk filesystem root directory.
  35  *
  36  * The directory defaults to the value from environment variable
  37  * DPKG_ROOT, and if not set the built-in default "".
  38  *
  39  * @return The filesystem root directory.
  40  */
  41 static char *
  42 dpkg_fsys_new_dir(void)
  43 {
  44         const char *env;
  45         char *dir;
  46
  47         env = getenv("DPKG_ROOT");
  48         if (env == NULL) {
  49                 dir = m_strdup("");
  50         } else {
  51                 dir = m_strdup(env);
  52                 path_trim_slash_slashdot(dir);
  53         }
  54
  55         return dir;
  56 }
  57
  58 /**
  59  * Set current on-disk filesystem root directory.
  60  *
  61  * This function can be used to set the directory to a new value, or to
  62  * reset it to a default value if dir is NULL.
  63  *
  64  * @param dir The new filesystem root directory, or NULL to set to default.
  65  *
  66  * @return The new filesystem root directory.
  67  */
  68 const char *
  69 dpkg_fsys_set_dir(const char *dir)
  70 {
  71         char *dir_new;
  72
  73         if (dir == NULL) {
  74                 dir_new = dpkg_fsys_new_dir();
  75         } else {
  76                 dir_new = m_strdup(dir);
  77                 path_trim_slash_slashdot(dir_new);
  78         }
  79
  80         free(fsys_dir);
  81         fsys_dir = dir_new;
  82
  83         return fsys_dir;
  84 }
  85
  86 /**
  87  * Get current on-disk filesystem root directory.
  88  *
  89  * This function will take care of initializing the directory if it has not
  90  * been initialized before.
  91  *
  92  * @return The current filesystem root directory.
  93  */
  94 const char *
  95 dpkg_fsys_get_dir(void)
  96 {
  97         if (fsys_dir == NULL)
  98                 fsys_dir = dpkg_fsys_new_dir();
  99
 100         return fsys_dir;
 101 }
 102
 103 /**
 104  * Get a pathname to the current on-disk filesystem root directory.
 105  *
 106  * This function returns an allocated string, which should be freed with
 107  * free(2).
 108  *
 109  * @param pathpart The pathpart to append to the new pathname.
 110  *
 111  * @return The newly allocated pathname.
 112  */
 113 char *
 114 dpkg_fsys_get_path(const char *pathpart)
 115 {
 116         pathpart = path_skip_slash_dotslash(pathpart);
 117
 118         return str_fmt("%s/%s", dpkg_fsys_get_dir(), pathpart);
 119 }