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                 char filename[UTIL_PATH_SIZE];
  93                 struct stat statbuf;
  94
  95                 if (dent->d_name[0] == '.')
  96                         continue;
  97                 util_strlcpy(syspath, path, sizeof(syspath));
  98                 util_strlcat(syspath, "/", sizeof(syspath));
  99                 util_strlcat(syspath, dent->d_name, sizeof(syspath));
 100                 util_strlcpy(filename, syspath, sizeof(filename));
 101                 util_strlcat(filename, "/uevent", sizeof(filename));
 102                 if (stat(filename, &statbuf) != 0)
 103                         continue;
 104                 util_resolve_sys_link(udev, syspath, sizeof(syspath));
 105                 list_entry_add(udev, devices_list, syspath, NULL, 1, 1);
 106         }
 107         closedir(dir);
 108         return 0;
 109 }
 110
 111 static int devices_scan_subsystems(struct udev *udev,
 112                                    const char *basedir, const char *subdir,
 113                                    struct udev_list_entry *subsystem_include_list,
 114                                    struct udev_list_entry *subsystem_exclude_list,
 115                                    struct list_node *devices_list)
 116 {
 117         if (subsystem_include_list != NULL) {
 118                 struct udev_list_entry *list_entry;
 119
 120                 /* if list of subsystems to scan is given, just use this list */
 121                 udev_list_entry_foreach(list_entry, subsystem_include_list) {
 122                         if (udev_list_entry_get_by_name(subsystem_exclude_list, udev_list_entry_get_name(list_entry)) != NULL)
 123                                         continue;
 124                         devices_scan_subsystem(udev, basedir, udev_list_entry_get_name(list_entry), subdir, devices_list);
 125                 }
 126         } else {
 127                 char path[UTIL_PATH_SIZE];
 128                 DIR *dir;
 129                 struct dirent *dent;
 130
 131                 /* if no list of subsystems to scan is given, scan all, and possible exclude some subsystems */
 132                 util_strlcpy(path, udev_get_sys_path(udev), sizeof(path));
 133                 util_strlcat(path, basedir, sizeof(path));
 134                 dir = opendir(path);
 135                 if (dir == NULL)
 136                         return -1;
 137                 for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 138                         if (dent->d_name[0] == '.')
 139                                 continue;
 140                         if (udev_list_entry_get_by_name(subsystem_exclude_list, dent->d_name) != NULL)
 141                                         continue;
 142                         devices_scan_subsystem(udev, basedir, dent->d_name, subdir, devices_list);
 143                 }
 144                 closedir(dir);
 145         }
 146         return 0;
 147 }
 148
 149 static int devices_delay(struct udev *udev, const char *syspath)
 150 {
 151         static const char *delay_device_list[] = {
 152                 "/block/md",
 153                 "/block/dm-",
 154                 NULL
 155         };
 156         size_t len;
 157         int i;
 158
 159         len = strlen(udev_get_sys_path(udev));
 160
 161         for (i = 0; delay_device_list[i] != NULL; i++) {
 162                 if (strstr(&syspath[len], delay_device_list[i]) != NULL) {
 163                         info(udev, "delaying: %s\n", syspath);
 164                         return 1;
 165                 }
 166         }
 167         return 0;
 168 }
 169
 170 static struct udev_enumerate *enumerate_new(struct udev *udev)
 171 {
 172         struct udev_enumerate *udev_enumerate;
 173
 174         udev_enumerate = malloc(sizeof(struct udev_enumerate));
 175         if (udev_enumerate == NULL)
 176                 return NULL;
 177         memset(udev_enumerate, 0x00, (sizeof(struct udev_enumerate)));
 178         udev_enumerate->refcount = 1;
 179         udev_enumerate->udev = udev;
 180         list_init(&udev_enumerate->devices_list);
 181         return udev_enumerate;
 182 }
 183
 184 /**
 185  * udev_enumerate_new_from_devices:
 186  * @udev: udev library context
 187  * @subsystem: the list of names of subsystems to look for devices
 188  *
 189  * Returns: an enumeration context
 190  **/
 191 struct udev_enumerate *udev_enumerate_new_from_devices(struct udev *udev, const char *subsystem, ...)
 192 {
 193         struct udev_enumerate *udev_enumerate;
 194         va_list vargs;
 195         const char *arg;
 196         char base[UTIL_PATH_SIZE];
 197         struct stat statbuf;
 198         struct list_node subsystem_include_list;
 199         struct list_node subsystem_exclude_list;
 200         struct udev_list_entry *list_entry;
 201
 202         if (udev == NULL)
 203                 return NULL;
 204
 205         udev_enumerate = enumerate_new(udev);
 206         if (udev_enumerate == NULL)
 207                 return NULL;
 208
 209         va_start(vargs, subsystem);
 210         list_init(&subsystem_include_list);
 211         list_init(&subsystem_exclude_list);
 212         for (arg = subsystem; arg != NULL; arg = va_arg(vargs, const char *)) {
 213                 if (arg[0] != '!')
 214                         list_entry_add(udev, &subsystem_include_list, arg, NULL, 1, 0);
 215                 else
 216                         list_entry_add(udev, &subsystem_exclude_list, &arg[1], NULL, 1, 0);
 217         }
 218         va_end(vargs);
 219
 220         util_strlcpy(base, udev_get_sys_path(udev), sizeof(base));
 221         util_strlcat(base, "/subsystem", sizeof(base));
 222         if (stat(base, &statbuf) == 0) {
 223                 /* we have /subsystem/, forget all the old stuff */
 224                 info(udev, "searching '/subsystem/*/devices/*' dir\n");
 225                 devices_scan_subsystems(udev, "/subsystem", "/devices",
 226                                         list_get_entry(&subsystem_include_list),
 227                                         list_get_entry(&subsystem_exclude_list),
 228                                         &udev_enumerate->devices_list);
 229         } else {
 230                 info(udev, "searching '/bus/*/devices/*' dir\n");
 231                 devices_scan_subsystems(udev, "/bus", "/devices",
 232                                         list_get_entry(&subsystem_include_list),
 233                                         list_get_entry(&subsystem_exclude_list),
 234                                         &udev_enumerate->devices_list);
 235                 info(udev, "searching '/class/*' dir\n");
 236                 devices_scan_subsystems(udev, "/class", NULL,
 237                                         list_get_entry(&subsystem_include_list),
 238                                         list_get_entry(&subsystem_exclude_list),
 239                                         &udev_enumerate->devices_list);
 240                 /* if block isn't a class, scan /block/ */
 241                 util_strlcpy(base, udev_get_sys_path(udev), sizeof(base));
 242                 util_strlcat(base, "/class/block", sizeof(base));
 243                 if (stat(base, &statbuf) != 0) {
 244                         struct udev_list_entry *include_list = list_get_entry(&subsystem_include_list);
 245                         struct udev_list_entry *exclude_list = list_get_entry(&subsystem_exclude_list);
 246                         int include_block = (include_list == NULL || udev_list_entry_get_by_name(include_list, "block") != NULL);
 247                         int exclude_block = (udev_list_entry_get_by_name(exclude_list, "block") != NULL);
 248
 249                         if (include_block && !exclude_block) {
 250                                 info(udev, "searching '/block/*/*' dir\n");
 251                                 /* scan disks */
 252                                 devices_scan_subsystem(udev, "/block", NULL, NULL, &udev_enumerate->devices_list);
 253                                 /* scan partitions */
 254                                 devices_scan_subsystems(udev, "/block", NULL,
 255                                                         NULL, NULL,
 256                                                         &udev_enumerate->devices_list);
 257                         }
 258                 }
 259         }
 260
 261         list_cleanup(udev, &subsystem_include_list);
 262         list_cleanup(udev, &subsystem_exclude_list);
 263
 264         /* sort delayed devices to the end of the list */
 265         udev_list_entry_foreach(list_entry, list_get_entry(&udev_enumerate->devices_list)) {
 266                 if (devices_delay(udev, udev_list_entry_get_name(list_entry)))
 267                         list_entry_move_to_end(list_entry);
 268         }
 269         return udev_enumerate;
 270 }
 271
 272 struct udev_enumerate *udev_enumerate_new_from_subsystems(struct udev *udev)
 273 {
 274         struct udev_enumerate *udev_enumerate;
 275         char base[UTIL_PATH_SIZE];
 276         struct stat statbuf;
 277         const char *subsysdir;
 278
 279         if (udev == NULL)
 280                 return NULL;
 281
 282         udev_enumerate = enumerate_new(udev);
 283         if (udev_enumerate == NULL)
 284                 return NULL;
 285
 286         util_strlcpy(base, udev_get_sys_path(udev), sizeof(base));
 287         util_strlcat(base, "/subsystem", sizeof(base));
 288         if (stat(base, &statbuf) == 0)
 289                 subsysdir = "/subsystem";
 290         else
 291                 subsysdir = "/bus";
 292         info(udev, "searching '%s/*' dir\n", subsysdir);
 293         devices_scan_subsystem(udev, subsysdir, NULL, NULL, &udev_enumerate->devices_list);
 294         info(udev, "searching '%s/*/drivers/*' dir\n", subsysdir);
 295         devices_scan_subsystems(udev, subsysdir, "/drivers",
 296                                 NULL, NULL,
 297                                 &udev_enumerate->devices_list);
 298         return udev_enumerate;
 299 }