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         struct udev *udev = udev_device_get_udev(dev);
  29         char filename[UTIL_PATH_SIZE];
  30
  31         id = udev_device_get_id_filename(dev);
  32         if (id == NULL)
  33                 return;
  34         util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/tags/", tag, "/", id, NULL);
  35
  36         if (add) {
  37                 util_create_path(udev, filename);
  38                 symlink(udev_device_get_devpath(dev), filename);
  39         } else {
  40                 unlink(filename);
  41         }
  42 }
  43
  44 int udev_device_tag_index(struct udev_device *dev, struct udev_device *dev_old, bool add)
  45 {
  46         struct udev_list_entry *list_entry;
  47         bool found;
  48
  49         if (add && dev_old != NULL) {
  50                 /* delete possible left-over tags */
  51                 udev_list_entry_foreach(list_entry, udev_device_get_tags_list_entry(dev_old)) {
  52                         const char *tag_old = udev_list_entry_get_name(list_entry);
  53                         struct udev_list_entry *list_entry_current;
  54
  55                         found = false;
  56                         udev_list_entry_foreach(list_entry_current, udev_device_get_tags_list_entry(dev)) {
  57                                 const char *tag = udev_list_entry_get_name(list_entry_current);
  58
  59                                 if (strcmp(tag, tag_old) == 0) {
  60                                         found = true;
  61                                         break;
  62                                 }
  63                         }
  64                         if (!found)
  65                                 udev_device_tag(dev_old, tag_old, false);
  66                 }
  67         }
  68
  69         udev_list_entry_foreach(list_entry, udev_device_get_tags_list_entry(dev))
  70                 udev_device_tag(dev, udev_list_entry_get_name(list_entry), add);
  71
  72         return 0;
  73 }
  74
  75 int udev_device_update_db(struct udev_device *udev_device)
  76 {
  77         const char *id;
  78         struct udev *udev = udev_device_get_udev(udev_device);
  79         char filename[UTIL_PATH_SIZE];
  80         char filename_tmp[UTIL_PATH_SIZE];
  81         FILE *f;
  82         char target[232]; /* on 64bit, tmpfs inlines up to 239 bytes */
  83         size_t devlen = strlen(udev_get_dev_path(udev))+1;
  84         char *s;
  85         size_t l;
  86         struct udev_list_entry *list_entry;
  87         int ret;
  88
  89         id = udev_device_get_id_filename(udev_device);
  90         if (id == NULL)
  91                 return -1;
  92         util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/db/", id, NULL);
  93         util_strscpyl(filename_tmp, sizeof(filename_tmp), filename, ".tmp", NULL);
  94
  95         udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(udev_device))
  96                 if (udev_list_entry_get_flags(list_entry))
  97                         goto file;
  98         if (udev_device_get_tags_list_entry(udev_device) != NULL)
  99                 goto file;
 100         if (udev_device_get_devlink_priority(udev_device) != 0)
 101                 goto file;
 102         if (udev_device_get_event_timeout(udev_device) >= 0)
 103                 goto file;
 104         if (udev_device_get_watch_handle(udev_device) >= 0)
 105                 goto file;
 106         if (udev_device_get_devnode(udev_device) == NULL)
 107                 goto out;
 108
 109         /*
 110          * if we have only the node and symlinks to store, try not to waste
 111          * tmpfs memory -- store values, if they fit, in a symlink target
 112          */
 113         s = target;
 114         l = util_strpcpy(&s, sizeof(target), &udev_device_get_devnode(udev_device)[devlen]);
 115         udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(udev_device)) {
 116                 l = util_strpcpyl(&s, l, " ", &udev_list_entry_get_name(list_entry)[devlen], NULL);
 117                 if (l == 0) {
 118                         info(udev, "size of links too large, create file\n");
 119                         goto file;
 120                 }
 121         }
 122         udev_selinux_setfscreatecon(udev, filename_tmp, S_IFLNK);
 123         util_create_path(udev, filename_tmp);
 124         ret = symlink(target, filename_tmp);
 125         udev_selinux_resetfscreatecon(udev);
 126         if (ret != 0)
 127                 goto file;
 128         ret = rename(filename_tmp, filename);
 129         if (ret != 0)
 130                 goto file;
 131         info(udev, "created db link (%s)\n", target);
 132         goto out;
 133 file:
 134         util_create_path(udev, filename_tmp);
 135         f = fopen(filename_tmp, "w");
 136         if (f == NULL) {
 137                 err(udev, "unable to create temporary db file '%s': %m\n", filename_tmp);
 138                 return -1;
 139         }
 140
 141         if (udev_device_get_devnode(udev_device) != NULL) {
 142                 fprintf(f, "N:%s\n", &udev_device_get_devnode(udev_device)[devlen]);
 143                 udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(udev_device))
 144                         fprintf(f, "S:%s\n", &udev_list_entry_get_name(list_entry)[devlen]);
 145         }
 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_event_timeout(udev_device) >= 0)
 149                 fprintf(f, "T:%i\n", udev_device_get_event_timeout(udev_device));
 150         if (udev_device_get_watch_handle(udev_device) >= 0)
 151                 fprintf(f, "W:%i\n", udev_device_get_watch_handle(udev_device));
 152         udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(udev_device)) {
 153                 if (!udev_list_entry_get_flags(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         udev_list_entry_foreach(list_entry, udev_device_get_tags_list_entry(udev_device))
 160                 fprintf(f, "G:%s\n", udev_list_entry_get_name(list_entry));
 161         fclose(f);
 162         rename(filename_tmp, filename);
 163         info(udev, "created db file for '%s' in '%s'\n", udev_device_get_devpath(udev_device), filename);
 164 out:
 165         return 0;
 166 }
 167
 168 int udev_device_delete_db(struct udev_device *udev_device)
 169 {
 170         const char *id;
 171         struct udev *udev = udev_device_get_udev(udev_device);
 172         char filename[UTIL_PATH_SIZE];
 173
 174         id = udev_device_get_id_filename(udev_device);
 175         if (id == NULL)
 176                 return -1;
 177         util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/db/", id, NULL);
 178         unlink(filename);
 179         return 0;
 180 }