udev/lib/libudev-device-db-write.c

   1 /*
   2  * libudev - interface to udev device information
   3  *
   4  * Copyright (C) 2008 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 <unistd.h>
  17 #include <fcntl.h>
  18 #include <string.h>
  19 #include <sys/stat.h>
  20
  21 #include "udev.h"
  22
  23 static size_t devpath_to_db_path(struct udev *udev, const char *devpath, char *filename, size_t len)
  24 {
  25         size_t start;
  26
  27         /* translate to location of db file */
  28         util_strlcpy(filename, udev_get_dev_path(udev), len);
  29         start = util_strlcat(filename, "/.udev/db/", len);
  30         util_strlcat(filename, devpath, len);
  31         return util_path_encode(&filename[start], len - start);
  32 }
  33
  34 int udev_device_update_db(struct udev_device *udev_device)
  35 {
  36         struct udev *udev = udev_device_get_udev(udev_device);
  37         char filename[UTIL_PATH_SIZE];
  38         FILE *f;
  39         char target[232]; /* on 64bit, tmpfs inlines up to 239 bytes */
  40         size_t devlen = strlen(udev_get_dev_path(udev))+1;
  41         struct udev_list_entry *list_entry;
  42         int ret;
  43
  44         devpath_to_db_path(udev,
  45                            udev_device_get_devpath(udev_device),
  46                            filename, sizeof(filename));
  47         util_create_path(udev, filename);
  48         unlink(filename);
  49
  50         udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(udev_device))
  51                 if (udev_list_entry_get_flag(list_entry))
  52                         goto file;
  53         if (udev_device_get_num_fake_partitions(udev_device) != 0)
  54                 goto file;
  55         if (udev_device_get_ignore_remove(udev_device))
  56                 goto file;
  57         if (udev_device_get_devlink_priority(udev_device) != 0)
  58                 goto file;
  59         if (udev_device_get_event_timeout(udev_device) >= 0)
  60                 goto file;
  61         if (udev_device_get_watch_handle(udev_device) >= 0)
  62                 goto file;
  63         if (udev_device_get_devnode(udev_device) == NULL)
  64                 goto out;
  65
  66         /*
  67          * if we have only the node and symlinks to store, try not to waste
  68          * tmpfs memory -- store values, if they fit, in a symlink target
  69          */
  70         util_strlcpy(target, &udev_device_get_devnode(udev_device)[devlen], sizeof(target));
  71         udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(udev_device)) {
  72                 size_t len;
  73
  74                 util_strlcat(target, " ", sizeof(target));
  75                 len = util_strlcat(target, &udev_list_entry_get_name(list_entry)[devlen], sizeof(target));
  76                 if (len >= sizeof(target)) {
  77                         info(udev, "size of links too large, create file\n");
  78                         goto file;
  79                 }
  80         }
  81         info(udev, "create db link (%s)\n", target);
  82         udev_selinux_setfscreatecon(udev, filename, S_IFLNK);
  83         ret = symlink(target, filename);
  84         udev_selinux_resetfscreatecon(udev);
  85         if (ret == 0)
  86                 goto out;
  87 file:
  88         f = fopen(filename, "w");
  89         if (f == NULL) {
  90                 err(udev, "unable to create db file '%s': %m\n", filename);
  91                 return -1;
  92                 }
  93         info(udev, "created db file for '%s' in '%s'\n", udev_device_get_devpath(udev_device), filename);
  94
  95         if (udev_device_get_devnode(udev_device) != NULL) {
  96                 fprintf(f, "N:%s\n", &udev_device_get_devnode(udev_device)[devlen]);
  97                 udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(udev_device))
  98                         fprintf(f, "S:%s\n", &udev_list_entry_get_name(list_entry)[devlen]);
  99         }
 100         if (udev_device_get_devlink_priority(udev_device) != 0)
 101                 fprintf(f, "L:%u\n", udev_device_get_devlink_priority(udev_device));
 102         if (udev_device_get_event_timeout(udev_device) >= 0)
 103                 fprintf(f, "T:%u\n", udev_device_get_event_timeout(udev_device));
 104         if (udev_device_get_num_fake_partitions(udev_device) != 0)
 105                 fprintf(f, "A:%u\n", udev_device_get_num_fake_partitions(udev_device));
 106         if (udev_device_get_ignore_remove(udev_device))
 107                 fprintf(f, "R:%u\n", udev_device_get_ignore_remove(udev_device));
 108         if (udev_device_get_watch_handle(udev_device) >= 0)
 109                 fprintf(f, "W:%u\n", udev_device_get_watch_handle(udev_device));
 110         udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(udev_device)) {
 111                 if (!udev_list_entry_get_flag(list_entry))
 112                         continue;
 113                 fprintf(f, "E:%s=%s\n",
 114                         udev_list_entry_get_name(list_entry),
 115                         udev_list_entry_get_value(list_entry));
 116         }
 117         fclose(f);
 118 out:
 119         return 0;
 120 }
 121
 122 int udev_device_delete_db(struct udev_device *udev_device)
 123 {
 124         char filename[UTIL_PATH_SIZE];
 125
 126         devpath_to_db_path(udev_device_get_udev(udev_device),
 127                            udev_device_get_devpath(udev_device),
 128                            filename, sizeof(filename));
 129         unlink(filename);
 130         return 0;
 131 }
 132
 133 int udev_device_rename_db(struct udev_device *udev_device, const char *devpath_old)
 134 {
 135         char filename_old[UTIL_PATH_SIZE];
 136         char filename[UTIL_PATH_SIZE];
 137
 138         devpath_to_db_path(udev_device_get_udev(udev_device),
 139                            devpath_old,
 140                            filename_old, sizeof(filename_old));
 141         devpath_to_db_path(udev_device_get_udev(udev_device),
 142                            udev_device_get_devpath(udev_device),
 143                            filename, sizeof(filename));
 144         return rename(filename_old, filename);
 145 }