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 <sys/stat.h>
  28
  29 #include "libudev.h"
  30 #include "libudev-private.h"
  31
  32 static void udev_device_tag(struct udev_device *dev, const char *tag, bool add)
  33 {
  34         const char *id;
  35         char filename[UTIL_PATH_SIZE];
  36
  37         id = udev_device_get_id_filename(dev);
  38         if (id == NULL)
  39                 return;
  40         strscpyl(filename, sizeof(filename), "/run/udev/tags/", tag, "/", id, NULL);
  41
  42         if (add) {
  43                 int fd;
  44
  45                 mkdir_parents(filename, 0755);
  46                 fd = open(filename, O_WRONLY|O_CREAT|O_CLOEXEC|O_TRUNC|O_NOFOLLOW, 0444);
  47                 if (fd >= 0)
  48                         close(fd);
  49         } else {
  50                 unlink(filename);
  51         }
  52 }
  53
  54 int udev_device_tag_index(struct udev_device *dev, struct udev_device *dev_old, bool add)
  55 {
  56         struct udev_list_entry *list_entry;
  57         bool found;
  58
  59         if (add && dev_old != NULL) {
  60                 /* delete possible left-over tags */
  61                 udev_list_entry_foreach(list_entry, udev_device_get_tags_list_entry(dev_old)) {
  62                         const char *tag_old = udev_list_entry_get_name(list_entry);
  63                         struct udev_list_entry *list_entry_current;
  64
  65                         found = false;
  66                         udev_list_entry_foreach(list_entry_current, udev_device_get_tags_list_entry(dev)) {
  67                                 const char *tag = udev_list_entry_get_name(list_entry_current);
  68
  69                                 if (streq(tag, tag_old)) {
  70                                         found = true;
  71                                         break;
  72                                 }
  73                         }
  74                         if (!found)
  75                                 udev_device_tag(dev_old, tag_old, false);
  76                 }
  77         }
  78
  79         udev_list_entry_foreach(list_entry, udev_device_get_tags_list_entry(dev))
  80                 udev_device_tag(dev, udev_list_entry_get_name(list_entry), add);
  81
  82         return 0;
  83 }
  84
  85 static bool device_has_info(struct udev_device *udev_device)
  86 {
  87         struct udev_list_entry *list_entry;
  88
  89         if (udev_device_get_devlinks_list_entry(udev_device) != NULL)
  90                 return true;
  91         if (udev_device_get_devlink_priority(udev_device) != 0)
  92                 return true;
  93         udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(udev_device))
  94                 if (udev_list_entry_get_num(list_entry))
  95                         return true;
  96         if (udev_device_get_tags_list_entry(udev_device) != NULL)
  97                 return true;
  98         if (udev_device_get_watch_handle(udev_device) >= 0)
  99                 return true;
 100         return false;
 101 }
 102
 103 int udev_device_update_db(struct udev_device *udev_device)
 104 {
 105         struct udev *udev = udev_device_get_udev(udev_device);
 106         bool has_info;
 107         const char *id;
 108         char filename[UTIL_PATH_SIZE];
 109         char filename_tmp[UTIL_PATH_SIZE];
 110         FILE *f;
 111         int r;
 112
 113         id = udev_device_get_id_filename(udev_device);
 114         if (id == NULL)
 115                 return -1;
 116
 117         has_info = device_has_info(udev_device);
 118         strscpyl(filename, sizeof(filename), "/run/udev/data/", id, NULL);
 119
 120         /* do not store anything for otherwise empty devices */
 121         if (!has_info &&
 122             major(udev_device_get_devnum(udev_device)) == 0 &&
 123             udev_device_get_ifindex(udev_device) == 0) {
 124                 unlink(filename);
 125                 return 0;
 126         }
 127
 128         /* write a database file */
 129         strscpyl(filename_tmp, sizeof(filename_tmp), filename, ".tmp", NULL);
 130         mkdir_parents(filename_tmp, 0755);
 131         f = fopen(filename_tmp, "we");
 132         if (f == NULL) {
 133                 udev_err(udev, "unable to create temporary db file '%s': %m\n", filename_tmp);
 134                 return -1;
 135         }
 136
 137         /*
 138          * set 'sticky' bit to indicate that we should not clean the
 139          * database when we transition from initramfs to the real root
 140          */
 141         if (udev_device_get_db_persist(udev_device))
 142                 fchmod(fileno(f), 01644);
 143
 144         if (has_info) {
 145                 struct udev_list_entry *list_entry;
 146
 147                 if (major(udev_device_get_devnum(udev_device)) > 0) {
 148                         udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(udev_device))
 149                                 fprintf(f, "S:%s\n", udev_list_entry_get_name(list_entry) + strlen("/dev/"));
 150                         if (udev_device_get_devlink_priority(udev_device) != 0)
 151                                 fprintf(f, "L:%i\n", udev_device_get_devlink_priority(udev_device));
 152                         if (udev_device_get_watch_handle(udev_device) >= 0)
 153                                 fprintf(f, "W:%i\n", udev_device_get_watch_handle(udev_device));
 154                 }
 155
 156                 if (udev_device_get_usec_initialized(udev_device) > 0)
 157                         fprintf(f, "I:%llu\n", (unsigned long long)udev_device_get_usec_initialized(udev_device));
 158
 159                 udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(udev_device)) {
 160                         if (!udev_list_entry_get_num(list_entry))
 161                                 continue;
 162                         fprintf(f, "E:%s=%s\n",
 163                                 udev_list_entry_get_name(list_entry),
 164                                 udev_list_entry_get_value(list_entry));
 165                 }
 166
 167                 udev_list_entry_foreach(list_entry, udev_device_get_tags_list_entry(udev_device))
 168                         fprintf(f, "G:%s\n", udev_list_entry_get_name(list_entry));
 169         }
 170
 171         fclose(f);
 172         r = rename(filename_tmp, filename);
 173         if (r < 0)
 174                 return -1;
 175         udev_dbg(udev, "created %s file '%s' for '%s'\n", has_info ? "db" : "empty",
 176              filename, udev_device_get_devpath(udev_device));
 177         return 0;
 178 }
 179
 180 int udev_device_delete_db(struct udev_device *udev_device)
 181 {
 182         const char *id;
 183         char filename[UTIL_PATH_SIZE];
 184
 185         id = udev_device_get_id_filename(udev_device);
 186         if (id == NULL)
 187                 return -1;
 188         strscpyl(filename, sizeof(filename), "/run/udev/data/", id, NULL);
 189         unlink(filename);
 190         return 0;
 191 }