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                 int fd;
  38
  39                 util_create_path(udev, filename);
  40                 fd = open(filename, O_WRONLY|O_CREAT|O_CLOEXEC|O_TRUNC|O_NOFOLLOW, 0444);
  41                 if (fd >= 0)
  42                         close(fd);
  43         } else {
  44                 unlink(filename);
  45         }
  46 }
  47
  48 int udev_device_tag_index(struct udev_device *dev, struct udev_device *dev_old, bool add)
  49 {
  50         struct udev_list_entry *list_entry;
  51         bool found;
  52
  53         if (add && dev_old != NULL) {
  54                 /* delete possible left-over tags */
  55                 udev_list_entry_foreach(list_entry, udev_device_get_tags_list_entry(dev_old)) {
  56                         const char *tag_old = udev_list_entry_get_name(list_entry);
  57                         struct udev_list_entry *list_entry_current;
  58
  59                         found = false;
  60                         udev_list_entry_foreach(list_entry_current, udev_device_get_tags_list_entry(dev)) {
  61                                 const char *tag = udev_list_entry_get_name(list_entry_current);
  62
  63                                 if (strcmp(tag, tag_old) == 0) {
  64                                         found = true;
  65                                         break;
  66                                 }
  67                         }
  68                         if (!found)
  69                                 udev_device_tag(dev_old, tag_old, false);
  70                 }
  71         }
  72
  73         udev_list_entry_foreach(list_entry, udev_device_get_tags_list_entry(dev))
  74                 udev_device_tag(dev, udev_list_entry_get_name(list_entry), add);
  75
  76         return 0;
  77 }
  78
  79 static bool device_has_info(struct udev_device *udev_device)
  80 {
  81         struct udev_list_entry *list_entry;
  82
  83         if (udev_device_get_devlinks_list_entry(udev_device) != NULL)
  84                 return true;
  85         if (udev_device_get_devlink_priority(udev_device) != 0)
  86                 return true;
  87         udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(udev_device))
  88                 if (udev_list_entry_get_flags(list_entry))
  89                         return true;
  90         if (udev_device_get_tags_list_entry(udev_device) != NULL)
  91                 return true;
  92         if (udev_device_get_knodename(udev_device) != NULL)
  93                 if (strcmp(udev_device_get_devnode(udev_device), udev_device_get_knodename(udev_device)) != 0)
  94                         return true;
  95         if (udev_device_get_watch_handle(udev_device) >= 0)
  96                 return true;
  97         return false;
  98 }
  99
 100 int udev_device_update_db(struct udev_device *udev_device)
 101 {
 102         bool has_info;
 103         const char *id;
 104         struct udev *udev = udev_device_get_udev(udev_device);
 105         char filename[UTIL_PATH_SIZE];
 106         char filename_tmp[UTIL_PATH_SIZE];
 107         FILE *f;
 108
 109         id = udev_device_get_id_filename(udev_device);
 110         if (id == NULL)
 111                 return -1;
 112
 113         has_info = device_has_info(udev_device);
 114         util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/db/", id, NULL);
 115
 116         /* do not store anything for otherwise empty devices */
 117         if (!has_info &&
 118             major(udev_device_get_devnum(udev_device)) == 0 &&
 119             udev_device_get_ifindex(udev_device) == 0) {
 120                 unlink(filename);
 121                 return 0;
 122         }
 123
 124         /* write a database file */
 125         util_strscpyl(filename_tmp, sizeof(filename_tmp), filename, ".tmp", NULL);
 126         util_create_path(udev, filename_tmp);
 127         f = fopen(filename_tmp, "we");
 128         if (f == NULL) {
 129                 err(udev, "unable to create temporary db file '%s': %m\n", filename_tmp);
 130                 return -1;
 131         }
 132
 133         if (has_info) {
 134                 size_t devlen = strlen(udev_get_dev_path(udev))+1;
 135                 struct udev_list_entry *list_entry;
 136
 137                 if (udev_device_get_devnode(udev_device) != NULL) {
 138                         fprintf(f, "N:%s\n", &udev_device_get_devnode(udev_device)[devlen]);
 139                         udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(udev_device))
 140                                 fprintf(f, "S:%s\n", &udev_list_entry_get_name(list_entry)[devlen]);
 141                 }
 142                 if (udev_device_get_devlink_priority(udev_device) != 0)
 143                         fprintf(f, "L:%i\n", udev_device_get_devlink_priority(udev_device));
 144                 if (udev_device_get_watch_handle(udev_device) >= 0)
 145                         fprintf(f, "W:%i\n", udev_device_get_watch_handle(udev_device));
 146                 udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(udev_device)) {
 147                         if (!udev_list_entry_get_flags(list_entry))
 148                                 continue;
 149                         fprintf(f, "E:%s=%s\n",
 150                                 udev_list_entry_get_name(list_entry),
 151                                 udev_list_entry_get_value(list_entry));
 152                 }
 153                 udev_list_entry_foreach(list_entry, udev_device_get_tags_list_entry(udev_device))
 154                         fprintf(f, "G:%s\n", udev_list_entry_get_name(list_entry));
 155         }
 156
 157         fclose(f);
 158         rename(filename_tmp, filename);
 159         info(udev, "created %s file '%s' for '%s'\n", has_info ? "db" : "empty",
 160              filename, udev_device_get_devpath(udev_device));
 161         return 0;
 162 }
 163
 164 int udev_device_delete_db(struct udev_device *udev_device)
 165 {
 166         const char *id;
 167         struct udev *udev = udev_device_get_udev(udev_device);
 168         char filename[UTIL_PATH_SIZE];
 169
 170         id = udev_device_get_id_filename(udev_device);
 171         if (id == NULL)
 172                 return -1;
 173         util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/db/", id, NULL);
 174         unlink(filename);
 175         return 0;
 176 }