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 <stdio.h>
  21 #include <string.h>
  22 #include <stddef.h>
  23 #include <stdbool.h>
  24 #include <unistd.h>
  25 #include <fcntl.h>
  26 #include <sys/stat.h>
  27
  28 #include "libudev.h"
  29 #include "libudev-private.h"
  30
  31 static void udev_device_tag(struct udev_device *dev, const char *tag, bool add)
  32 {
  33         const char *id;
  34         char filename[UTIL_PATH_SIZE];
  35
  36         id = udev_device_get_id_filename(dev);
  37         if (id == NULL)
  38                 return;
  39         strscpyl(filename, sizeof(filename), "/run/udev/tags/", tag, "/", id, NULL);
  40
  41         if (add) {
  42                 int fd;
  43
  44                 mkdir_parents(filename, 0755);
  45                 fd = open(filename, O_WRONLY|O_CREAT|O_CLOEXEC|O_TRUNC|O_NOFOLLOW, 0444);
  46                 if (fd >= 0)
  47                         close(fd);
  48         } else {
  49                 unlink(filename);
  50         }
  51 }
  52
  53 int udev_device_tag_index(struct udev_device *dev, struct udev_device *dev_old, bool add)
  54 {
  55         struct udev_list_entry *list_entry;
  56         bool found;
  57
  58         if (add && dev_old != NULL) {
  59                 /* delete possible left-over tags */
  60                 udev_list_entry_foreach(list_entry, udev_device_get_tags_list_entry(dev_old)) {
  61                         const char *tag_old = udev_list_entry_get_name(list_entry);
  62                         struct udev_list_entry *list_entry_current;
  63
  64                         found = false;
  65                         udev_list_entry_foreach(list_entry_current, udev_device_get_tags_list_entry(dev)) {
  66                                 const char *tag = udev_list_entry_get_name(list_entry_current);
  67
  68                                 if (streq(tag, tag_old)) {
  69                                         found = true;
  70                                         break;
  71                                 }
  72                         }
  73                         if (!found)
  74                                 udev_device_tag(dev_old, tag_old, false);
  75                 }
  76         }
  77
  78         udev_list_entry_foreach(list_entry, udev_device_get_tags_list_entry(dev))
  79                 udev_device_tag(dev, udev_list_entry_get_name(list_entry), add);
  80
  81         return 0;
  82 }
  83
  84 static bool device_has_info(struct udev_device *udev_device)
  85 {
  86         struct udev_list_entry *list_entry;
  87
  88         if (udev_device_get_devlinks_list_entry(udev_device) != NULL)
  89                 return true;
  90         if (udev_device_get_devlink_priority(udev_device) != 0)
  91                 return true;
  92         udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(udev_device))
  93                 if (udev_list_entry_get_num(list_entry))
  94                         return true;
  95         if (udev_device_get_tags_list_entry(udev_device) != NULL)
  96                 return true;
  97         if (udev_device_get_watch_handle(udev_device) >= 0)
  98                 return true;
  99         return false;
 100 }
 101
 102 int udev_device_update_db(struct udev_device *udev_device)
 103 {
 104         bool has_info;
 105         const char *id;
 106         char filename[UTIL_PATH_SIZE];
 107         char filename_tmp[UTIL_PATH_SIZE];
 108         FILE *f;
 109         int r;
 110
 111         id = udev_device_get_id_filename(udev_device);
 112         if (id == NULL)
 113                 return -1;
 114
 115         has_info = device_has_info(udev_device);
 116         strscpyl(filename, sizeof(filename), "/run/udev/data/", id, NULL);
 117
 118         /* do not store anything for otherwise empty devices */
 119         if (!has_info &&
 120             major(udev_device_get_devnum(udev_device)) == 0 &&
 121             udev_device_get_ifindex(udev_device) == 0) {
 122                 unlink(filename);
 123                 return 0;
 124         }
 125
 126         /* write a database file */
 127         strscpyl(filename_tmp, sizeof(filename_tmp), filename, ".tmp", NULL);
 128         mkdir_parents(filename_tmp, 0755);
 129         f = fopen(filename_tmp, "we");
 130         if (f == NULL)
 131                 return log_debug_errno(errno, "unable to create temporary db file '%s': %m", filename_tmp);
 132
 133         /*
 134          * set 'sticky' bit to indicate that we should not clean the
 135          * database when we transition from initramfs to the real root
 136          */
 137         if (udev_device_get_db_persist(udev_device))
 138                 fchmod(fileno(f), 01644);
 139
 140         if (has_info) {
 141                 struct udev_list_entry *list_entry;
 142
 143                 if (major(udev_device_get_devnum(udev_device)) > 0) {
 144                         udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(udev_device))
 145                                 fprintf(f, "S:%s\n", udev_list_entry_get_name(list_entry) + strlen("/dev/"));
 146                         if (udev_device_get_devlink_priority(udev_device) != 0)
 147                                 fprintf(f, "L:%i\n", udev_device_get_devlink_priority(udev_device));
 148                         if (udev_device_get_watch_handle(udev_device) >= 0)
 149                                 fprintf(f, "W:%i\n", udev_device_get_watch_handle(udev_device));
 150                 }
 151
 152                 if (udev_device_get_usec_initialized(udev_device) > 0)
 153                         fprintf(f, "I:"USEC_FMT"\n", udev_device_get_usec_initialized(udev_device));
 154
 155                 udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(udev_device)) {
 156                         if (!udev_list_entry_get_num(list_entry))
 157                                 continue;
 158                         fprintf(f, "E:%s=%s\n",
 159                                 udev_list_entry_get_name(list_entry),
 160                                 udev_list_entry_get_value(list_entry));
 161                 }
 162
 163                 udev_list_entry_foreach(list_entry, udev_device_get_tags_list_entry(udev_device))
 164                         fprintf(f, "G:%s\n", udev_list_entry_get_name(list_entry));
 165         }
 166
 167         fclose(f);
 168         r = rename(filename_tmp, filename);
 169         if (r < 0)
 170                 return -1;
 171         log_debug("created %s file '%s' for '%s'", has_info ? "db" : "empty",
 172              filename, udev_device_get_devpath(udev_device));
 173         return 0;
 174 }
 175
 176 int udev_device_delete_db(struct udev_device *udev_device)
 177 {
 178         const char *id;
 179         char filename[UTIL_PATH_SIZE];
 180
 181         id = udev_device_get_id_filename(udev_device);
 182         if (id == NULL)
 183                 return -1;
 184         strscpyl(filename, sizeof(filename), "/run/udev/data/", id, NULL);
 185         unlink(filename);
 186         return 0;
 187 }