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         struct udev *udev = udev_device_get_udev(dev);
  28         char filename[UTIL_PATH_SIZE];
  29
  30         util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/tags/", tag, "/",
  31                       udev_device_get_subsystem(dev), ":", udev_device_get_sysname(dev), NULL);
  32
  33         if (add) {
  34                 util_create_path(udev, filename);
  35                 symlink(udev_device_get_devpath(dev), filename);
  36                 /* possibly cleanup old entries after a device renaming */
  37                 if (udev_device_get_sysname_old(dev) != NULL) {
  38                         char filename_old[UTIL_PATH_SIZE];
  39
  40                         util_strscpyl(filename_old, sizeof(filename_old), udev_get_dev_path(udev), "/.udev/tags/", tag, "/",
  41                                       udev_device_get_subsystem(dev), ":", udev_device_get_sysname_old(dev), NULL);
  42                         unlink(filename_old);
  43                 }
  44         } else {
  45                 unlink(filename);
  46         }
  47 }
  48
  49 int udev_device_tag_index(struct udev_device *dev, struct udev_device *dev_old, bool add)
  50 {
  51         struct udev_list_entry *list_entry;
  52         bool found;
  53
  54         if (add && dev_old != NULL) {
  55                 /* delete possible left-over tags */
  56                 udev_list_entry_foreach(list_entry, udev_device_get_tags_list_entry(dev_old)) {
  57                         const char *tag_old = udev_list_entry_get_name(list_entry);
  58                         struct udev_list_entry *list_entry_current;
  59
  60                         found = false;
  61                         udev_list_entry_foreach(list_entry_current, udev_device_get_tags_list_entry(dev)) {
  62                                 const char *tag = udev_list_entry_get_name(list_entry_current);
  63
  64                                 if (strcmp(tag, tag_old) == 0) {
  65                                         found = true;
  66                                         break;
  67                                 }
  68                         }
  69                         if (!found)
  70                                 udev_device_tag(dev_old, tag_old, false);
  71                 }
  72         }
  73
  74         udev_list_entry_foreach(list_entry, udev_device_get_tags_list_entry(dev))
  75                 udev_device_tag(dev, udev_list_entry_get_name(list_entry), add);
  76
  77         return 0;
  78 }
  79
  80 int udev_device_update_db(struct udev_device *udev_device)
  81 {
  82         struct udev *udev = udev_device_get_udev(udev_device);
  83         char filename[UTIL_PATH_SIZE];
  84         char filename_tmp[UTIL_PATH_SIZE];
  85         FILE *f;
  86         char target[232]; /* on 64bit, tmpfs inlines up to 239 bytes */
  87         size_t devlen = strlen(udev_get_dev_path(udev))+1;
  88         char *s;
  89         size_t l;
  90         struct udev_list_entry *list_entry;
  91         int ret;
  92
  93         util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/db/",
  94                       udev_device_get_subsystem(udev_device), ":", udev_device_get_sysname(udev_device), NULL);
  95         util_strscpyl(filename_tmp, sizeof(filename_tmp), filename, ".tmp", NULL);
  96
  97         udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(udev_device))
  98                 if (udev_list_entry_get_flags(list_entry))
  99                         goto file;
 100         if (udev_device_get_tags_list_entry(udev_device) != NULL)
 101                 goto file;
 102         if (udev_device_get_devlink_priority(udev_device) != 0)
 103                 goto file;
 104         if (udev_device_get_event_timeout(udev_device) >= 0)
 105                 goto file;
 106         if (udev_device_get_watch_handle(udev_device) >= 0)
 107                 goto file;
 108         if (udev_device_get_devnode(udev_device) == NULL)
 109                 goto out;
 110
 111         /*
 112          * if we have only the node and symlinks to store, try not to waste
 113          * tmpfs memory -- store values, if they fit, in a symlink target
 114          */
 115         s = target;
 116         l = util_strpcpy(&s, sizeof(target), &udev_device_get_devnode(udev_device)[devlen]);
 117         udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(udev_device)) {
 118                 l = util_strpcpyl(&s, l, " ", &udev_list_entry_get_name(list_entry)[devlen], NULL);
 119                 if (l == 0) {
 120                         info(udev, "size of links too large, create file\n");
 121                         goto file;
 122                 }
 123         }
 124         udev_selinux_setfscreatecon(udev, filename_tmp, S_IFLNK);
 125         util_create_path(udev, filename_tmp);
 126         ret = symlink(target, filename_tmp);
 127         udev_selinux_resetfscreatecon(udev);
 128         if (ret != 0)
 129                 goto file;
 130         ret = rename(filename_tmp, filename);
 131         if (ret != 0)
 132                 goto file;
 133         info(udev, "created db link (%s)\n", target);
 134         goto out;
 135 file:
 136         util_create_path(udev, filename_tmp);
 137         f = fopen(filename_tmp, "w");
 138         if (f == NULL) {
 139                 err(udev, "unable to create temporary db file '%s': %m\n", filename_tmp);
 140                 return -1;
 141         }
 142
 143         if (udev_device_get_devnode(udev_device) != NULL) {
 144                 fprintf(f, "N:%s\n", &udev_device_get_devnode(udev_device)[devlen]);
 145                 udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(udev_device))
 146                         fprintf(f, "S:%s\n", &udev_list_entry_get_name(list_entry)[devlen]);
 147         }
 148         if (udev_device_get_devlink_priority(udev_device) != 0)
 149                 fprintf(f, "L:%i\n", udev_device_get_devlink_priority(udev_device));
 150         if (udev_device_get_event_timeout(udev_device) >= 0)
 151                 fprintf(f, "T:%i\n", udev_device_get_event_timeout(udev_device));
 152         if (udev_device_get_watch_handle(udev_device) >= 0)
 153                 fprintf(f, "W:%i\n", udev_device_get_watch_handle(udev_device));
 154         udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(udev_device)) {
 155                 if (!udev_list_entry_get_flags(list_entry))
 156                         continue;
 157                 fprintf(f, "E:%s=%s\n",
 158                         udev_list_entry_get_name(list_entry),
 159                         udev_list_entry_get_value(list_entry));
 160         }
 161         udev_list_entry_foreach(list_entry, udev_device_get_tags_list_entry(udev_device))
 162                 fprintf(f, "G:%s\n", udev_list_entry_get_name(list_entry));
 163         fclose(f);
 164         rename(filename_tmp, filename);
 165         info(udev, "created db file for '%s' in '%s'\n", udev_device_get_devpath(udev_device), filename);
 166 out:
 167         return 0;
 168 }
 169
 170 int udev_device_delete_db(struct udev_device *udev_device)
 171 {
 172         struct udev *udev = udev_device_get_udev(udev_device);
 173         char filename[UTIL_PATH_SIZE];
 174
 175         util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/db/",
 176                       udev_device_get_subsystem(udev_device), ":", udev_device_get_sysname(udev_device), NULL);
 177         unlink(filename);
 178         return 0;
 179 }