libudev/libudev-device-private.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 "libudev.h"
  22 #include "libudev-private.h"
  23
  24 int udev_device_update_db(struct udev_device *udev_device)
  25 {
  26         struct udev *udev = udev_device_get_udev(udev_device);
  27         char filename[UTIL_PATH_SIZE];
  28         char filename_tmp[UTIL_PATH_SIZE];
  29         FILE *f;
  30         char target[232]; /* on 64bit, tmpfs inlines up to 239 bytes */
  31         size_t devlen = strlen(udev_get_dev_path(udev))+1;
  32         char *s;
  33         size_t l;
  34         struct udev_list_entry *list_entry;
  35         int ret;
  36
  37         util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/db/",
  38                       udev_device_get_subsystem(udev_device), ":", udev_device_get_sysname(udev_device), NULL);
  39         util_strscpyl(filename_tmp, sizeof(filename_tmp), filename, ".tmp", NULL);
  40
  41         udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(udev_device))
  42                 if (udev_list_entry_get_flags(list_entry))
  43                         goto file;
  44         if (udev_device_get_devlink_priority(udev_device) != 0)
  45                 goto file;
  46         if (udev_device_get_event_timeout(udev_device) >= 0)
  47                 goto file;
  48         if (udev_device_get_watch_handle(udev_device) >= 0)
  49                 goto file;
  50         if (udev_device_get_devnode(udev_device) == NULL)
  51                 goto out;
  52
  53         /*
  54          * if we have only the node and symlinks to store, try not to waste
  55          * tmpfs memory -- store values, if they fit, in a symlink target
  56          */
  57         s = target;
  58         l = util_strpcpy(&s, sizeof(target), &udev_device_get_devnode(udev_device)[devlen]);
  59         udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(udev_device)) {
  60                 l = util_strpcpyl(&s, l, " ", &udev_list_entry_get_name(list_entry)[devlen], NULL);
  61                 if (l == 0) {
  62                         info(udev, "size of links too large, create file\n");
  63                         goto file;
  64                 }
  65         }
  66         udev_selinux_setfscreatecon(udev, filename_tmp, S_IFLNK);
  67         util_create_path(udev, filename_tmp);
  68         ret = symlink(target, filename_tmp);
  69         udev_selinux_resetfscreatecon(udev);
  70         if (ret != 0)
  71                 goto file;
  72         ret = rename(filename_tmp, filename);
  73         if (ret != 0)
  74                 goto file;
  75         info(udev, "created db link (%s)\n", target);
  76         goto out;
  77 file:
  78         util_create_path(udev, filename_tmp);
  79         f = fopen(filename_tmp, "w");
  80         if (f == NULL) {
  81                 err(udev, "unable to create temporary db file '%s': %m\n", filename_tmp);
  82                 return -1;
  83                 }
  84
  85         if (udev_device_get_devnode(udev_device) != NULL) {
  86                 fprintf(f, "N:%s\n", &udev_device_get_devnode(udev_device)[devlen]);
  87                 udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(udev_device))
  88                         fprintf(f, "S:%s\n", &udev_list_entry_get_name(list_entry)[devlen]);
  89         }
  90         if (udev_device_get_devlink_priority(udev_device) != 0)
  91                 fprintf(f, "L:%i\n", udev_device_get_devlink_priority(udev_device));
  92         if (udev_device_get_event_timeout(udev_device) >= 0)
  93                 fprintf(f, "T:%i\n", udev_device_get_event_timeout(udev_device));
  94         if (udev_device_get_watch_handle(udev_device) >= 0)
  95                 fprintf(f, "W:%i\n", udev_device_get_watch_handle(udev_device));
  96         udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(udev_device)) {
  97                 if (!udev_list_entry_get_flags(list_entry))
  98                         continue;
  99                 fprintf(f, "E:%s=%s\n",
 100                         udev_list_entry_get_name(list_entry),
 101                         udev_list_entry_get_value(list_entry));
 102         }
 103         fclose(f);
 104         rename(filename_tmp, filename);
 105         info(udev, "created db file for '%s' in '%s'\n", udev_device_get_devpath(udev_device), filename);
 106 out:
 107         return 0;
 108 }
 109
 110 int udev_device_delete_db(struct udev_device *udev_device)
 111 {
 112         struct udev *udev = udev_device_get_udev(udev_device);
 113         char filename[UTIL_PATH_SIZE];
 114
 115         util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/db/",
 116                       udev_device_get_subsystem(udev_device), ":", udev_device_get_sysname(udev_device), NULL);
 117         unlink(filename);
 118         return 0;
 119 }
 120
 121 int udev_device_rename_db(struct udev_device *udev_device)
 122 {
 123         struct udev *udev = udev_device_get_udev(udev_device);
 124         char filename_old[UTIL_PATH_SIZE];
 125         char filename[UTIL_PATH_SIZE];
 126
 127         util_strscpyl(filename_old, sizeof(filename_old), udev_get_dev_path(udev), "/.udev/db/",
 128                       udev_device_get_subsystem(udev_device), ":", udev_device_get_sysname_old(udev_device), NULL);
 129         util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/db/",
 130                       udev_device_get_subsystem(udev_device), ":", udev_device_get_sysname(udev_device), NULL);
 131         return rename(filename_old, filename);
 132 }