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