udev/lib/libudev-enumerate.c

   1 /*
   2  * libudev - interface to udev device information
   3  *
   4  * Copyright (C) 2008 Kay Sievers <kay.sievers@vrfy.org>
   5  *
   6  * This program is free software: you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation, either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <stddef.h>
  23 #include <unistd.h>
  24 #include <errno.h>
  25 #include <string.h>
  26 #include <dirent.h>
  27 #include <sys/stat.h>
  28
  29 #include "libudev.h"
  30 #include "libudev-private.h"
  31
  32 struct udev_enumerate {
  33         struct udev *udev;
  34         int refcount;
  35         struct list_node devices_list;
  36 };
  37
  38 struct udev_enumerate *udev_enumerate_ref(struct udev_enumerate *udev_enumerate)
  39 {
  40         if (udev_enumerate == NULL)
  41                 return NULL;
  42         udev_enumerate->refcount++;
  43         return udev_enumerate;
  44 }
  45
  46 void udev_enumerate_unref(struct udev_enumerate *udev_enumerate)
  47 {
  48         if (udev_enumerate == NULL)
  49                 return;
  50         udev_enumerate->refcount--;
  51         if (udev_enumerate->refcount > 0)
  52                 return;
  53         list_cleanup(udev_enumerate->udev, &udev_enumerate->devices_list);
  54         free(udev_enumerate);
  55 }
  56
  57 struct udev *udev_enumerate_get_udev(struct udev_enumerate *udev_enumerate)
  58 {
  59         if (udev_enumerate == NULL)
  60                 return NULL;
  61         return udev_enumerate->udev;
  62 }
  63
  64 struct udev_list_entry *udev_enumerate_get_list_entry(struct udev_enumerate *udev_enumerate)
  65 {
  66         if (udev_enumerate == NULL)
  67                 return NULL;
  68         return list_get_entry(&udev_enumerate->devices_list);
  69 }
  70
  71 static int devices_scan_subsystem(struct udev *udev,
  72                                   const char *basedir, const char *subsystem, const char *subdir,
  73                                   struct list_node *devices_list)
  74 {
  75         char path[UTIL_PATH_SIZE];
  76         DIR *dir;
  77         struct dirent *dent;
  78
  79         util_strlcpy(path, udev_get_sys_path(udev), sizeof(path));
  80         util_strlcat(path, basedir, sizeof(path));
  81         util_strlcat(path, "/", sizeof(path));
  82         util_strlcat(path, subsystem, sizeof(path));
  83         if (subdir != NULL)
  84                 util_strlcat(path, subdir, sizeof(path));
  85         dir = opendir(path);
  86         if (dir == NULL)
  87                 return -1;
  88         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
  89                 char syspath[UTIL_PATH_SIZE];
  90
  91                 if (dent->d_name[0] == '.')
  92                         continue;
  93                 util_strlcpy(syspath, path, sizeof(syspath));
  94                 util_strlcat(syspath, "/", sizeof(syspath));
  95                 util_strlcat(syspath, dent->d_name, sizeof(syspath));
  96                 util_resolve_sys_link(udev, syspath, sizeof(syspath));
  97                 list_entry_add(udev, devices_list, syspath, NULL, 1, 1);
  98         }
  99         closedir(dir);
 100         return 0;
 101 }
 102
 103 static int devices_scan_subsystems(struct udev *udev,
 104                                    const char *basedir, const char *subdir,
 105                                    struct udev_list_entry *subsystem_include_list,
 106                                    struct udev_list_entry *subsystem_exclude_list,
 107                                    struct list_node *devices_list)
 108 {
 109         if (subsystem_include_list != NULL) {
 110                 struct udev_list_entry *list_entry;
 111
 112                 /* if list of subsystems to scan is given, just use this list */
 113                 udev_list_entry_foreach(list_entry, subsystem_include_list)
 114                         devices_scan_subsystem(udev, basedir, udev_list_entry_get_name(list_entry), subdir, devices_list);
 115         } else {
 116                 char path[UTIL_PATH_SIZE];
 117                 DIR *dir;
 118                 struct dirent *dent;
 119
 120                 /* if no list of subsystems to scan is given, scan all, and possible exclude some subsystems */
 121                 util_strlcpy(path, udev_get_sys_path(udev), sizeof(path));
 122                 util_strlcat(path, basedir, sizeof(path));
 123                 dir = opendir(path);
 124                 if (dir == NULL)
 125                         return -1;
 126                 for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 127                         if (dent->d_name[0] == '.')
 128                                 continue;
 129                         if (udev_list_entry_get_by_name(subsystem_exclude_list, dent->d_name) != NULL)
 130                                         continue;
 131                         devices_scan_subsystem(udev, basedir, dent->d_name, subdir, devices_list);
 132                 }
 133                 closedir(dir);
 134         }
 135         return 0;
 136 }
 137
 138 static int devices_delay(struct udev *udev, const char *syspath)
 139 {
 140         static const char *delay_device_list[] = {
 141                 "/block/md",
 142                 "/block/dm-",
 143                 NULL
 144         };
 145         size_t len;
 146         int i;
 147
 148         len = strlen(udev_get_sys_path(udev));
 149
 150         for (i = 0; delay_device_list[i] != NULL; i++) {
 151                 if (strstr(&syspath[len], delay_device_list[i]) != NULL) {
 152                         info(udev, "delaying: %s\n", syspath);
 153                         return 1;
 154                 }
 155         }
 156         return 0;
 157 }
 158
 159 /**
 160  * udev_enumerate_new_from_devices:
 161  * @udev: udev library context
 162  * @subsystem: the list of names of subsystems to look for devices
 163  *
 164  * Returns: an enumeration context
 165  **/
 166 struct udev_enumerate *udev_enumerate_new_from_devices(struct udev *udev, const char *subsystem, ...)
 167 {
 168         struct udev_enumerate *udev_enumerate;
 169         va_list vargs;
 170         const char *arg;
 171         char base[UTIL_PATH_SIZE];
 172         struct stat statbuf;
 173         struct list_node subsystem_include_list;
 174         struct list_node subsystem_exclude_list;
 175         struct udev_list_entry *list_entry;
 176
 177         if (udev == NULL)
 178                 return NULL;
 179
 180         udev_enumerate = malloc(sizeof(struct udev_enumerate));
 181         if (udev_enumerate == NULL)
 182                 return NULL;
 183         memset(udev_enumerate, 0x00, (sizeof(struct udev_enumerate)));
 184         udev_enumerate->refcount = 1;
 185         udev_enumerate->udev = udev;
 186         list_init(&udev_enumerate->devices_list);
 187
 188         va_start(vargs, subsystem);
 189         list_init(&subsystem_include_list);
 190         list_init(&subsystem_exclude_list);
 191         for (arg = subsystem; arg != NULL; arg = va_arg(vargs, const char *)) {
 192                 if (arg[0] != '!')
 193                         list_entry_add(udev, &subsystem_include_list, arg, NULL, 1, 0);
 194                 else
 195                         list_entry_add(udev, &subsystem_exclude_list, &arg[1], NULL, 1, 0);
 196         }
 197         va_end(vargs);
 198
 199         /* if we have /sys/subsystem/, forget all the old stuff */
 200         util_strlcpy(base, udev_get_sys_path(udev), sizeof(base));
 201         util_strlcat(base, "/subsystem", sizeof(base));
 202         if (stat(base, &statbuf) == 0) {
 203                 info(udev, "searching 'subsystem/*/devices/*' dir\n");
 204                 devices_scan_subsystems(udev, "/subsystem", "/devices",
 205                                         list_get_entry(&subsystem_include_list),
 206                                         list_get_entry(&subsystem_exclude_list),
 207                                         &udev_enumerate->devices_list);
 208         } else {
 209                 info(udev, "searching 'bus/*/devices/*' dir\n");
 210                 devices_scan_subsystems(udev, "/bus", "/devices",
 211                                         list_get_entry(&subsystem_include_list),
 212                                         list_get_entry(&subsystem_exclude_list),
 213                                         &udev_enumerate->devices_list);
 214                 info(udev, "searching 'class/*' dir\n");
 215                 devices_scan_subsystems(udev, "/class", NULL,
 216                                         list_get_entry(&subsystem_include_list),
 217                                         list_get_entry(&subsystem_exclude_list),
 218                                         &udev_enumerate->devices_list);
 219         }
 220
 221         list_cleanup(udev, &subsystem_include_list);
 222         list_cleanup(udev, &subsystem_exclude_list);
 223
 224         /* sort delayed devices to the end of the list */
 225         udev_list_entry_foreach(list_entry, list_get_entry(&udev_enumerate->devices_list)) {
 226                 if (devices_delay(udev, udev_list_entry_get_name(list_entry)))
 227                         list_entry_move_to_end(list_entry);
 228         }
 229         return udev_enumerate;
 230 }
 231
 232 struct udev_enumerate *udev_enumerate_new_from_subsystems(struct udev *udev)
 233 {
 234         return NULL;
 235 }