src/libudev/libudev-device-private.c

   1 /*
   2  * libudev - interface to udev device information
   3  *
   4  * Copyright (C) 2008-2010 Kay Sievers <kay.sievers@vrfy.org>
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  */
  11
  12 #include <stdlib.h>
  13 #include <stdio.h>
  14 #include <string.h>
  15 #include <stddef.h>
  16 #include <stdbool.h>
  17 #include <unistd.h>
  18 #include <fcntl.h>
  19 #include <string.h>
  20 #include <sys/stat.h>
  21
  22 #include "libudev.h"
  23 #include "libudev-private.h"
  24
  25 static void udev_device_tag(struct udev_device *dev, const char *tag, bool add)
  26 {
  27         const char *id;
  28         char filename[UTIL_PATH_SIZE];
  29
  30         id = udev_device_get_id_filename(dev);
  31         if (id == NULL)
  32                 return;
  33         util_strscpyl(filename, sizeof(filename), "/run/udev/tags/", tag, "/", id, NULL);
  34
  35         if (add) {
  36                 int fd;
  37
  38                 mkdir_parents(filename, 0755);
  39                 fd = open(filename, O_WRONLY|O_CREAT|O_CLOEXEC|O_TRUNC|O_NOFOLLOW, 0444);
  40                 if (fd >= 0)
  41                         close(fd);
  42         } else {
  43                 unlink(filename);
  44         }
  45 }
  46
  47 int udev_device_tag_index(struct udev_device *dev, struct udev_device *dev_old, bool add)
  48 {
  49         struct udev_list_entry *list_entry;
  50         bool found;
  51
  52         if (add && dev_old != NULL) {
  53                 /* delete possible left-over tags */
  54                 udev_list_entry_foreach(list_entry, udev_device_get_tags_list_entry(dev_old)) {
  55                         const char *tag_old = udev_list_entry_get_name(list_entry);
  56                         struct udev_list_entry *list_entry_current;
  57
  58                         found = false;
  59                         udev_list_entry_foreach(list_entry_current, udev_device_get_tags_list_entry(dev)) {
  60                                 const char *tag = udev_list_entry_get_name(list_entry_current);
  61
  62                                 if (streq(tag, tag_old)) {
  63                                         found = true;
  64                                         break;
  65                                 }
  66                         }
  67                         if (!found)
  68                                 udev_device_tag(dev_old, tag_old, false);
  69                 }
  70         }
  71
  72         udev_list_entry_foreach(list_entry, udev_device_get_tags_list_entry(dev))
  73                 udev_device_tag(dev, udev_list_entry_get_name(list_entry), add);
  74
  75         return 0;
  76 }
  77
  78 static bool device_has_info(struct udev_device *udev_device)
  79 {
  80         struct udev_list_entry *list_entry;
  81
  82         if (udev_device_get_devlinks_list_entry(udev_device) != NULL)
  83                 return true;
  84         if (udev_device_get_devlink_priority(udev_device) != 0)
  85                 return true;
  86         udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(udev_device))
  87                 if (udev_list_entry_get_num(list_entry))
  88                         return true;
  89         if (udev_device_get_tags_list_entry(udev_device) != NULL)
  90                 return true;
  91         if (udev_device_get_watch_handle(udev_device) >= 0)
  92                 return true;
  93         return false;
  94 }
  95
  96 int udev_device_update_db(struct udev_device *udev_device)
  97 {
  98         struct udev *udev = udev_device_get_udev(udev_device);
  99         bool has_info;
 100         const char *id;
 101         char filename[UTIL_PATH_SIZE];
 102         char filename_tmp[UTIL_PATH_SIZE];
 103         FILE *f;
 104         int r;
 105
 106         id = udev_device_get_id_filename(udev_device);
 107         if (id == NULL)
 108                 return -1;
 109
 110         has_info = device_has_info(udev_device);
 111         util_strscpyl(filename, sizeof(filename), "/run/udev/data/", id, NULL);
 112
 113         /* do not store anything for otherwise empty devices */
 114         if (!has_info &&
 115             major(udev_device_get_devnum(udev_device)) == 0 &&
 116             udev_device_get_ifindex(udev_device) == 0) {
 117                 unlink(filename);
 118                 return 0;
 119         }
 120
 121         /* write a database file */
 122         util_strscpyl(filename_tmp, sizeof(filename_tmp), filename, ".tmp", NULL);
 123         mkdir_parents(filename_tmp, 0755);
 124         f = fopen(filename_tmp, "we");
 125         if (f == NULL) {
 126                 udev_err(udev, "unable to create temporary db file '%s': %m\n", filename_tmp);
 127                 return -1;
 128         }
 129
 130         /*
 131          * set 'sticky' bit to indicate that we should not clean the
 132          * database when we transition from initramfs to the real root
 133          */
 134         if (udev_device_get_db_persist(udev_device))
 135                 fchmod(fileno(f), 01644);
 136
 137         if (has_info) {
 138                 struct udev_list_entry *list_entry;
 139
 140                 if (major(udev_device_get_devnum(udev_device)) > 0) {
 141                         udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(udev_device))
 142                                 fprintf(f, "S:%s\n", udev_list_entry_get_name(list_entry) + strlen("/dev/"));
 143                         if (udev_device_get_devlink_priority(udev_device) != 0)
 144                                 fprintf(f, "L:%i\n", udev_device_get_devlink_priority(udev_device));
 145                         if (udev_device_get_watch_handle(udev_device) >= 0)
 146                                 fprintf(f, "W:%i\n", udev_device_get_watch_handle(udev_device));
 147                 }
 148
 149                 if (udev_device_get_usec_initialized(udev_device) > 0)
 150                         fprintf(f, "I:%llu\n", udev_device_get_usec_initialized(udev_device));
 151
 152                 udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(udev_device)) {
 153                         if (!udev_list_entry_get_num(list_entry))
 154                                 continue;
 155                         fprintf(f, "E:%s=%s\n",
 156                                 udev_list_entry_get_name(list_entry),
 157                                 udev_list_entry_get_value(list_entry));
 158                 }
 159
 160                 udev_list_entry_foreach(list_entry, udev_device_get_tags_list_entry(udev_device))
 161                         fprintf(f, "G:%s\n", udev_list_entry_get_name(list_entry));
 162         }
 163
 164         fclose(f);
 165         r = rename(filename_tmp, filename);
 166         if (r < 0)
 167                 return -1;
 168         udev_dbg(udev, "created %s file '%s' for '%s'\n", has_info ? "db" : "empty",
 169              filename, udev_device_get_devpath(udev_device));
 170         return 0;
 171 }
 172
 173 int udev_device_delete_db(struct udev_device *udev_device)
 174 {
 175         const char *id;
 176         char filename[UTIL_PATH_SIZE];
 177
 178         id = udev_device_get_id_filename(udev_device);
 179         if (id == NULL)
 180                 return -1;
 181         util_strscpyl(filename, sizeof(filename), "/run/udev/data/", id, NULL);
 182         unlink(filename);
 183         return 0;
 184 }