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 static bool device_has_info(struct udev_device *udev_device)
  76 {
  77         struct udev_list_entry *list_entry;
  78
  79         if (udev_device_get_devlinks_list_entry(udev_device) != NULL)
  80                 return true;
  81         if (udev_device_get_devlink_priority(udev_device) != 0)
  82                 return true;
  83         udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(udev_device))
  84                 if (udev_list_entry_get_flags(list_entry))
  85                         return true;
  86         if (udev_device_get_tags_list_entry(udev_device) != NULL)
  87                 return true;
  88         if (udev_device_get_watch_handle(udev_device) >= 0)
  89                 return true;
  90         return false;
  91 }
  92
  93 int udev_device_update_db(struct udev_device *udev_device)
  94 {
  95         bool has_info;
  96         const char *id;
  97         struct udev *udev = udev_device_get_udev(udev_device);
  98         char filename[UTIL_PATH_SIZE];
  99         char filename_tmp[UTIL_PATH_SIZE];
 100         FILE *f;
 101         size_t devlen = strlen(udev_get_dev_path(udev))+1;
 102
 103         id = udev_device_get_id_filename(udev_device);
 104         if (id == NULL)
 105                 return -1;
 106
 107         has_info = device_has_info(udev_device);
 108         util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/db/", id, NULL);
 109
 110         /* do not store anything for otherwise empty devices */
 111         if (!has_info && udev_device_get_devnode(udev_device) == NULL) {
 112                 unlink(filename);
 113                 return 0;
 114         }
 115
 116         /* write a database file */
 117         util_strscpyl(filename_tmp, sizeof(filename_tmp), filename, ".tmp", NULL);
 118         util_create_path(udev, filename_tmp);
 119         f = fopen(filename_tmp, "we");
 120         if (f == NULL) {
 121                 err(udev, "unable to create temporary db file '%s': %m\n", filename_tmp);
 122                 return -1;
 123         }
 124
 125         if (has_info) {
 126                 struct udev_list_entry *list_entry;
 127
 128                 if (udev_device_get_devnode(udev_device) != NULL) {
 129                         fprintf(f, "N:%s\n", &udev_device_get_devnode(udev_device)[devlen]);
 130                         udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(udev_device))
 131                                 fprintf(f, "S:%s\n", &udev_list_entry_get_name(list_entry)[devlen]);
 132                 }
 133                 if (udev_device_get_devlink_priority(udev_device) != 0)
 134                         fprintf(f, "L:%i\n", udev_device_get_devlink_priority(udev_device));
 135                 if (udev_device_get_watch_handle(udev_device) >= 0)
 136                         fprintf(f, "W:%i\n", udev_device_get_watch_handle(udev_device));
 137                 udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(udev_device)) {
 138                         if (!udev_list_entry_get_flags(list_entry))
 139                                 continue;
 140                         fprintf(f, "E:%s=%s\n",
 141                                 udev_list_entry_get_name(list_entry),
 142                                 udev_list_entry_get_value(list_entry));
 143                 }
 144                 udev_list_entry_foreach(list_entry, udev_device_get_tags_list_entry(udev_device))
 145                         fprintf(f, "G:%s\n", udev_list_entry_get_name(list_entry));
 146         }
 147
 148         fclose(f);
 149         rename(filename_tmp, filename);
 150         info(udev, "created %s file '%s' for '%s'\n", has_info ? "db" : "empty",
 151              filename, udev_device_get_devpath(udev_device));
 152         return 0;
 153 }
 154
 155 int udev_device_delete_db(struct udev_device *udev_device)
 156 {
 157         const char *id;
 158         struct udev *udev = udev_device_get_udev(udev_device);
 159         char filename[UTIL_PATH_SIZE];
 160
 161         id = udev_device_get_id_filename(udev_device);
 162         if (id == NULL)
 163                 return -1;
 164         util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/db/", id, NULL);
 165         unlink(filename);
 166         return 0;
 167 }