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         if (subsystem != NULL) {
  82                 util_strlcat(path, "/", sizeof(path));
  83                 util_strlcat(path, subsystem, sizeof(path));
  84         }
  85         if (subdir != NULL)
  86                 util_strlcat(path, subdir, sizeof(path));
  87         dir = opendir(path);
  88         if (dir == NULL)
  89                 return -1;
  90         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
  91                 char syspath[UTIL_PATH_SIZE];
  92                 struct stat statbuf;
  93
  94                 if (dent->d_name[0] == '.')
  95                         continue;
  96                 util_strlcpy(syspath, path, sizeof(syspath));
  97                 util_strlcat(syspath, "/", sizeof(syspath));
  98                 util_strlcat(syspath, dent->d_name, sizeof(syspath));
  99                 if (stat(syspath, &statbuf) != 0)
 100                         continue;
 101                 if (!S_ISDIR(statbuf.st_mode))
 102                         continue;
 103                 util_resolve_sys_link(udev, syspath, sizeof(syspath));
 104                 list_entry_add(udev, devices_list, syspath, NULL, 1, 1);
 105         }
 106         closedir(dir);
 107         return 0;
 108 }
 109
 110 static int devices_scan_subsystems(struct udev *udev,
 111                                    const char *basedir, const char *subdir,
 112                                    struct udev_list_entry *subsystem_include_list,
 113                                    struct udev_list_entry *subsystem_exclude_list,
 114                                    struct list_node *devices_list)
 115 {
 116         if (subsystem_include_list != NULL) {
 117                 struct udev_list_entry *list_entry;
 118
 119                 /* if list of subsystems to scan is given, just use this list */
 120                 udev_list_entry_foreach(list_entry, subsystem_include_list)
 121                         devices_scan_subsystem(udev, basedir, udev_list_entry_get_name(list_entry), subdir, devices_list);
 122         } else {
 123                 char path[UTIL_PATH_SIZE];
 124                 DIR *dir;
 125                 struct dirent *dent;
 126
 127                 /* if no list of subsystems to scan is given, scan all, and possible exclude some subsystems */
 128                 util_strlcpy(path, udev_get_sys_path(udev), sizeof(path));
 129                 util_strlcat(path, basedir, sizeof(path));
 130                 dir = opendir(path);
 131                 if (dir == NULL)
 132                         return -1;
 133                 for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 134                         if (dent->d_name[0] == '.')
 135                                 continue;
 136                         if (udev_list_entry_get_by_name(subsystem_exclude_list, dent->d_name) != NULL)
 137                                         continue;
 138                         devices_scan_subsystem(udev, basedir, dent->d_name, subdir, devices_list);
 139                 }
 140                 closedir(dir);
 141         }
 142         return 0;
 143 }
 144
 145 static int devices_delay(struct udev *udev, const char *syspath)
 146 {
 147         static const char *delay_device_list[] = {
 148                 "/block/md",
 149                 "/block/dm-",
 150                 NULL
 151         };
 152         size_t len;
 153         int i;
 154
 155         len = strlen(udev_get_sys_path(udev));
 156
 157         for (i = 0; delay_device_list[i] != NULL; i++) {
 158                 if (strstr(&syspath[len], delay_device_list[i]) != NULL) {
 159                         info(udev, "delaying: %s\n", syspath);
 160                         return 1;
 161                 }
 162         }
 163         return 0;
 164 }
 165
 166 static struct udev_enumerate *enumerate_new(struct udev *udev)
 167 {
 168         struct udev_enumerate *udev_enumerate;
 169
 170         udev_enumerate = malloc(sizeof(struct udev_enumerate));
 171         if (udev_enumerate == NULL)
 172                 return NULL;
 173         memset(udev_enumerate, 0x00, (sizeof(struct udev_enumerate)));
 174         udev_enumerate->refcount = 1;
 175         udev_enumerate->udev = udev;
 176         list_init(&udev_enumerate->devices_list);
 177         return udev_enumerate;
 178 }
 179
 180 /**
 181  * udev_enumerate_new_from_devices:
 182  * @udev: udev library context
 183  * @subsystem: the list of names of subsystems to look for devices
 184  *
 185  * Returns: an enumeration context
 186  **/
 187 struct udev_enumerate *udev_enumerate_new_from_devices(struct udev *udev, const char *subsystem, ...)
 188 {
 189         struct udev_enumerate *udev_enumerate;
 190         va_list vargs;
 191         const char *arg;
 192         char base[UTIL_PATH_SIZE];
 193         struct stat statbuf;
 194         struct list_node subsystem_include_list;
 195         struct list_node subsystem_exclude_list;
 196         struct udev_list_entry *list_entry;
 197
 198         if (udev == NULL)
 199                 return NULL;
 200
 201         udev_enumerate = enumerate_new(udev);
 202         if (udev_enumerate == NULL)
 203                 return NULL;
 204
 205         va_start(vargs, subsystem);
 206         list_init(&subsystem_include_list);
 207         list_init(&subsystem_exclude_list);
 208         for (arg = subsystem; arg != NULL; arg = va_arg(vargs, const char *)) {
 209                 if (arg[0] != '!')
 210                         list_entry_add(udev, &subsystem_include_list, arg, NULL, 1, 0);
 211                 else
 212                         list_entry_add(udev, &subsystem_exclude_list, &arg[1], NULL, 1, 0);
 213         }
 214         va_end(vargs);
 215
 216         /* if we have /sys/subsystem/, forget all the old stuff */
 217         util_strlcpy(base, udev_get_sys_path(udev), sizeof(base));
 218         util_strlcat(base, "/subsystem", sizeof(base));
 219         if (stat(base, &statbuf) == 0) {
 220                 info(udev, "searching '/subsystem/*/devices/*' dir\n");
 221                 devices_scan_subsystems(udev, "/subsystem", "/devices",
 222                                         list_get_entry(&subsystem_include_list),
 223                                         list_get_entry(&subsystem_exclude_list),
 224                                         &udev_enumerate->devices_list);
 225         } else {
 226                 info(udev, "searching '/bus/*/devices/*' dir\n");
 227                 devices_scan_subsystems(udev, "/bus", "/devices",
 228                                         list_get_entry(&subsystem_include_list),
 229                                         list_get_entry(&subsystem_exclude_list),
 230                                         &udev_enumerate->devices_list);
 231                 info(udev, "searching '/class/*' dir\n");
 232                 devices_scan_subsystems(udev, "/class", NULL,
 233                                         list_get_entry(&subsystem_include_list),
 234                                         list_get_entry(&subsystem_exclude_list),
 235                                         &udev_enumerate->devices_list);
 236         }
 237
 238         list_cleanup(udev, &subsystem_include_list);
 239         list_cleanup(udev, &subsystem_exclude_list);
 240
 241         /* sort delayed devices to the end of the list */
 242         udev_list_entry_foreach(list_entry, list_get_entry(&udev_enumerate->devices_list)) {
 243                 if (devices_delay(udev, udev_list_entry_get_name(list_entry)))
 244                         list_entry_move_to_end(list_entry);
 245         }
 246         return udev_enumerate;
 247 }
 248
 249 struct udev_enumerate *udev_enumerate_new_from_subsystems(struct udev *udev)
 250 {
 251         struct udev_enumerate *udev_enumerate;
 252         char base[UTIL_PATH_SIZE];
 253         struct stat statbuf;
 254         const char *subsysdir;
 255
 256         if (udev == NULL)
 257                 return NULL;
 258
 259         udev_enumerate = enumerate_new(udev);
 260         if (udev_enumerate == NULL)
 261                 return NULL;
 262
 263         util_strlcpy(base, udev_get_sys_path(udev), sizeof(base));
 264         util_strlcat(base, "/subsystem", sizeof(base));
 265         if (stat(base, &statbuf) == 0)
 266                 subsysdir = "/subsystem";
 267         else
 268                 subsysdir = "/bus";
 269         info(udev, "searching '%s/*' dir\n", subsysdir);
 270         devices_scan_subsystem(udev, subsysdir, NULL, NULL, &udev_enumerate->devices_list);
 271         info(udev, "searching '%s/*/drivers/*' dir\n", subsysdir);
 272         devices_scan_subsystems(udev, subsysdir, "/drivers",
 273                                 NULL, NULL,
 274                                 &udev_enumerate->devices_list);
 275         return udev_enumerate;
 276 }