src/libudev/libudev-device-private.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2008-2012 Kay Sievers <kay@vrfy.org>
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include <stdlib.h>
  21 #include <stdio.h>
  22 #include <string.h>
  23 #include <stddef.h>
  24 #include <stdbool.h>
  25 #include <unistd.h>
  26 #include <fcntl.h>
  27 #include <string.h>
  28 #include <sys/stat.h>
  29
  30 #include "libudev.h"
  31 #include "libudev-private.h"
  32
  33 static void udev_device_tag(struct udev_device *dev, const char *tag, bool add)
  34 {
  35         const char *id;
  36         char filename[UTIL_PATH_SIZE];
  37
  38         id = udev_device_get_id_filename(dev);
  39         if (id == NULL)
  40                 return;
  41         strscpyl(filename, sizeof(filename), "/run/udev/tags/", tag, "/", id, NULL);
  42
  43         if (add) {
  44                 int fd;
  45
  46                 mkdir_parents(filename, 0755);
  47                 fd = open(filename, O_WRONLY|O_CREAT|O_CLOEXEC|O_TRUNC|O_NOFOLLOW, 0444);
  48                 if (fd >= 0)
  49                         close(fd);
  50         } else {
  51                 unlink(filename);
  52         }
  53 }
  54
  55 int udev_device_tag_index(struct udev_device *dev, struct udev_device *dev_old, bool add)
  56 {
  57         struct udev_list_entry *list_entry;
  58         bool found;
  59
  60         if (add && dev_old != NULL) {
  61                 /* delete possible left-over tags */
  62                 udev_list_entry_foreach(list_entry, udev_device_get_tags_list_entry(dev_old)) {
  63                         const char *tag_old = udev_list_entry_get_name(list_entry);
  64                         struct udev_list_entry *list_entry_current;
  65
  66                         found = false;
  67                         udev_list_entry_foreach(list_entry_current, udev_device_get_tags_list_entry(dev)) {
  68                                 const char *tag = udev_list_entry_get_name(list_entry_current);
  69
  70                                 if (streq(tag, tag_old)) {
  71                                         found = true;
  72                                         break;
  73                                 }
  74                         }
  75                         if (!found)
  76                                 udev_device_tag(dev_old, tag_old, false);
  77                 }
  78         }
  79
  80         udev_list_entry_foreach(list_entry, udev_device_get_tags_list_entry(dev))
  81                 udev_device_tag(dev, udev_list_entry_get_name(list_entry), add);
  82
  83         return 0;
  84 }
  85
  86 static bool device_has_info(struct udev_device *udev_device)
  87 {
  88         struct udev_list_entry *list_entry;
  89
  90         if (udev_device_get_devlinks_list_entry(udev_device) != NULL)
  91                 return true;
  92         if (udev_device_get_devlink_priority(udev_device) != 0)
  93                 return true;
  94         udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(udev_device))
  95                 if (udev_list_entry_get_num(list_entry))
  96                         return true;
  97         if (udev_device_get_tags_list_entry(udev_device) != NULL)
  98                 return true;
  99         if (udev_device_get_watch_handle(udev_device) >= 0)
 100                 return true;
 101         return false;
 102 }
 103
 104 int udev_device_update_db(struct udev_device *udev_device)
 105 {
 106         struct udev *udev = udev_device_get_udev(udev_device);
 107         bool has_info;
 108         const char *id;
 109         char filename[UTIL_PATH_SIZE];
 110         char filename_tmp[UTIL_PATH_SIZE];
 111         FILE *f;
 112         int r;
 113
 114         id = udev_device_get_id_filename(udev_device);
 115         if (id == NULL)
 116                 return -1;
 117
 118         has_info = device_has_info(udev_device);
 119         strscpyl(filename, sizeof(filename), "/run/udev/data/", id, NULL);
 120
 121         /* do not store anything for otherwise empty devices */
 122         if (!has_info &&
 123             major(udev_device_get_devnum(udev_device)) == 0 &&
 124             udev_device_get_ifindex(udev_device) == 0) {
 125                 unlink(filename);
 126                 return 0;
 127         }
 128
 129         /* write a database file */
 130         strscpyl(filename_tmp, sizeof(filename_tmp), filename, ".tmp", NULL);
 131         mkdir_parents(filename_tmp, 0755);
 132         f = fopen(filename_tmp, "we");
 133         if (f == NULL) {
 134                 udev_err(udev, "unable to create temporary db file '%s': %m\n", filename_tmp);
 135                 return -1;
 136         }
 137
 138         /*
 139          * set 'sticky' bit to indicate that we should not clean the
 140          * database when we transition from initramfs to the real root
 141          */
 142         if (udev_device_get_db_persist(udev_device))
 143                 fchmod(fileno(f), 01644);
 144
 145         if (has_info) {
 146                 struct udev_list_entry *list_entry;
 147
 148                 if (major(udev_device_get_devnum(udev_device)) > 0) {
 149                         udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(udev_device))
 150                                 fprintf(f, "S:%s\n", udev_list_entry_get_name(list_entry) + strlen("/dev/"));
 151                         if (udev_device_get_devlink_priority(udev_device) != 0)
 152                                 fprintf(f, "L:%i\n", udev_device_get_devlink_priority(udev_device));
 153                         if (udev_device_get_watch_handle(udev_device) >= 0)
 154                                 fprintf(f, "W:%i\n", udev_device_get_watch_handle(udev_device));
 155                 }
 156
 157                 if (udev_device_get_usec_initialized(udev_device) > 0)
 158                         fprintf(f, "I:%llu\n", (unsigned long long)udev_device_get_usec_initialized(udev_device));
 159
 160                 udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(udev_device)) {
 161                         if (!udev_list_entry_get_num(list_entry))
 162                                 continue;
 163                         fprintf(f, "E:%s=%s\n",
 164                                 udev_list_entry_get_name(list_entry),
 165                                 udev_list_entry_get_value(list_entry));
 166                 }
 167
 168                 udev_list_entry_foreach(list_entry, udev_device_get_tags_list_entry(udev_device))
 169                         fprintf(f, "G:%s\n", udev_list_entry_get_name(list_entry));
 170         }
 171
 172         fclose(f);
 173         r = rename(filename_tmp, filename);
 174         if (r < 0)
 175                 return -1;
 176         udev_dbg(udev, "created %s file '%s' for '%s'\n", has_info ? "db" : "empty",
 177              filename, udev_device_get_devpath(udev_device));
 178         return 0;
 179 }
 180
 181 int udev_device_delete_db(struct udev_device *udev_device)
 182 {
 183         const char *id;
 184         char filename[UTIL_PATH_SIZE];
 185
 186         id = udev_device_get_id_filename(udev_device);
 187         if (id == NULL)
 188                 return -1;
 189         strscpyl(filename, sizeof(filename), "/run/udev/data/", id, NULL);
 190         unlink(filename);
 191         return 0;
 192 }