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 int udev_device_tag_index(struct udev_device *udev_device, bool add)
  26 {
  27         struct udev *udev = udev_device_get_udev(udev_device);
  28         struct udev_list_entry *list_entry;
  29
  30         udev_list_entry_foreach(list_entry, udev_device_get_tags_list_entry(udev_device)) {
  31                 char filename[UTIL_PATH_SIZE];
  32
  33                 util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/tags/",
  34                               udev_list_entry_get_name(list_entry), "/",
  35                               udev_device_get_subsystem(udev_device), ":", udev_device_get_sysname(udev_device), NULL);
  36
  37                 if (add) {
  38                         util_create_path(udev, filename);
  39                         symlink(udev_device_get_devpath(udev_device), filename);
  40                         if (udev_device_get_sysname_old(udev_device) != NULL) {
  41                                 char filename_old[UTIL_PATH_SIZE];
  42
  43                                 util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/tags/",
  44                                               udev_list_entry_get_name(list_entry),
  45                                               udev_device_get_subsystem(udev_device), ":", udev_device_get_sysname_old(udev_device), NULL);
  46                                 unlink(filename_old);
  47                         }
  48                 } else {
  49                         unlink(filename);
  50                         util_delete_path(udev, filename);
  51                 }
  52         }
  53         return 0;
  54 }
  55
  56 int udev_device_update_db(struct udev_device *udev_device)
  57 {
  58         struct udev *udev = udev_device_get_udev(udev_device);
  59         char filename[UTIL_PATH_SIZE];
  60         char filename_tmp[UTIL_PATH_SIZE];
  61         FILE *f;
  62         char target[232]; /* on 64bit, tmpfs inlines up to 239 bytes */
  63         size_t devlen = strlen(udev_get_dev_path(udev))+1;
  64         char *s;
  65         size_t l;
  66         struct udev_list_entry *list_entry;
  67         int ret;
  68
  69         util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/db/",
  70                       udev_device_get_subsystem(udev_device), ":", udev_device_get_sysname(udev_device), NULL);
  71         util_strscpyl(filename_tmp, sizeof(filename_tmp), filename, ".tmp", NULL);
  72
  73         udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(udev_device))
  74                 if (udev_list_entry_get_flags(list_entry))
  75                         goto file;
  76         if (udev_device_get_tags_list_entry(udev_device) != NULL)
  77                 goto file;
  78         if (udev_device_get_devlink_priority(udev_device) != 0)
  79                 goto file;
  80         if (udev_device_get_event_timeout(udev_device) >= 0)
  81                 goto file;
  82         if (udev_device_get_watch_handle(udev_device) >= 0)
  83                 goto file;
  84         if (udev_device_get_devnode(udev_device) == NULL)
  85                 goto out;
  86
  87         /*
  88          * if we have only the node and symlinks to store, try not to waste
  89          * tmpfs memory -- store values, if they fit, in a symlink target
  90          */
  91         s = target;
  92         l = util_strpcpy(&s, sizeof(target), &udev_device_get_devnode(udev_device)[devlen]);
  93         udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(udev_device)) {
  94                 l = util_strpcpyl(&s, l, " ", &udev_list_entry_get_name(list_entry)[devlen], NULL);
  95                 if (l == 0) {
  96                         info(udev, "size of links too large, create file\n");
  97                         goto file;
  98                 }
  99         }
 100         udev_selinux_setfscreatecon(udev, filename_tmp, S_IFLNK);
 101         util_create_path(udev, filename_tmp);
 102         ret = symlink(target, filename_tmp);
 103         udev_selinux_resetfscreatecon(udev);
 104         if (ret != 0)
 105                 goto file;
 106         ret = rename(filename_tmp, filename);
 107         if (ret != 0)
 108                 goto file;
 109         info(udev, "created db link (%s)\n", target);
 110         goto out;
 111 file:
 112         util_create_path(udev, filename_tmp);
 113         f = fopen(filename_tmp, "w");
 114         if (f == NULL) {
 115                 err(udev, "unable to create temporary db file '%s': %m\n", filename_tmp);
 116                 return -1;
 117         }
 118
 119         if (udev_device_get_devnode(udev_device) != NULL) {
 120                 fprintf(f, "N:%s\n", &udev_device_get_devnode(udev_device)[devlen]);
 121                 udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(udev_device))
 122                         fprintf(f, "S:%s\n", &udev_list_entry_get_name(list_entry)[devlen]);
 123         }
 124         if (udev_device_get_devlink_priority(udev_device) != 0)
 125                 fprintf(f, "L:%i\n", udev_device_get_devlink_priority(udev_device));
 126         if (udev_device_get_event_timeout(udev_device) >= 0)
 127                 fprintf(f, "T:%i\n", udev_device_get_event_timeout(udev_device));
 128         if (udev_device_get_watch_handle(udev_device) >= 0)
 129                 fprintf(f, "W:%i\n", udev_device_get_watch_handle(udev_device));
 130         udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(udev_device)) {
 131                 if (!udev_list_entry_get_flags(list_entry))
 132                         continue;
 133                 fprintf(f, "E:%s=%s\n",
 134                         udev_list_entry_get_name(list_entry),
 135                         udev_list_entry_get_value(list_entry));
 136         }
 137         udev_list_entry_foreach(list_entry, udev_device_get_tags_list_entry(udev_device))
 138                 fprintf(f, "G:%s\n", udev_list_entry_get_name(list_entry));
 139         fclose(f);
 140         rename(filename_tmp, filename);
 141         info(udev, "created db file for '%s' in '%s'\n", udev_device_get_devpath(udev_device), filename);
 142 out:
 143         udev_device_tag_index(udev_device, true);
 144         return 0;
 145 }
 146
 147 int udev_device_delete_db(struct udev_device *udev_device)
 148 {
 149         struct udev *udev = udev_device_get_udev(udev_device);
 150         char filename[UTIL_PATH_SIZE];
 151
 152         udev_device_tag_index(udev_device, false);
 153         util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/db/",
 154                       udev_device_get_subsystem(udev_device), ":", udev_device_get_sysname(udev_device), NULL);
 155         unlink(filename);
 156         return 0;
 157 }
 158
 159 int udev_device_rename_db(struct udev_device *udev_device)
 160 {
 161         struct udev *udev = udev_device_get_udev(udev_device);
 162         char filename_old[UTIL_PATH_SIZE];
 163         char filename[UTIL_PATH_SIZE];
 164
 165         if (strcmp(udev_device_get_sysname(udev_device), udev_device_get_sysname_old(udev_device)) == 0)
 166                 return 0;
 167
 168         util_strscpyl(filename_old, sizeof(filename_old), udev_get_dev_path(udev), "/.udev/db/",
 169                       udev_device_get_subsystem(udev_device), ":", udev_device_get_sysname_old(udev_device), NULL);
 170         util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/db/",
 171                       udev_device_get_subsystem(udev_device), ":", udev_device_get_sysname(udev_device), NULL);
 172         udev_device_tag_index(udev_device, true);
 173         return rename(filename_old, filename);
 174 }