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_head 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_list *udev_enumerate_get_devices_list(struct udev_enumerate *udev_enumerate)
  58 {
  59         if (udev_enumerate == NULL)
  60                 return NULL;
  61         return list_get_entry(&udev_enumerate->devices_list);
  62 }
  63
  64 static int devices_scan_subsystem(struct udev *udev,
  65                                   const char *basedir, const char *subsystem, const char *subdir,
  66                                   struct list_head *device_list)
  67 {
  68         char path[UTIL_PATH_SIZE];
  69         DIR *dir;
  70         struct dirent *dent;
  71
  72         util_strlcpy(path, udev_get_sys_path(udev), sizeof(path));
  73         util_strlcat(path, basedir, sizeof(path));
  74         util_strlcat(path, "/", sizeof(path));
  75         util_strlcat(path, subsystem, sizeof(path));
  76         if (subdir != NULL)
  77                 util_strlcat(path, subdir, sizeof(path));
  78         dir = opendir(path);
  79         if (dir == NULL)
  80                 return -1;
  81         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
  82                 char syspath[UTIL_PATH_SIZE];
  83
  84                 if (dent->d_name[0] == '.')
  85                         continue;
  86                 util_strlcpy(syspath, path, sizeof(syspath));
  87                 util_strlcat(syspath, "/", sizeof(syspath));
  88                 util_strlcat(syspath, dent->d_name, sizeof(syspath));
  89                 util_resolve_sys_link(udev, syspath, sizeof(syspath));
  90                 list_insert(udev, device_list, syspath, NULL, 1);
  91         }
  92         closedir(dir);
  93         return 0;
  94 }
  95
  96 static int devices_scan_subsystems(struct udev *udev,
  97                                    const char *basedir, const char *subsystem, const char *subdir,
  98                                    struct list_head *device_list)
  99 {
 100         char path[UTIL_PATH_SIZE];
 101         DIR *dir;
 102         struct dirent *dent;
 103
 104         if (subsystem != NULL)
 105                 return devices_scan_subsystem(udev, basedir, subsystem, subdir, device_list);
 106
 107         util_strlcpy(path, udev_get_sys_path(udev), sizeof(path));
 108         util_strlcat(path, basedir, sizeof(path));
 109         dir = opendir(path);
 110         if (dir == NULL)
 111                 return -1;
 112         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 113                 if (dent->d_name[0] == '.')
 114                         continue;
 115                 devices_scan_subsystem(udev, basedir, dent->d_name, subdir, device_list);
 116         }
 117         closedir(dir);
 118         return 0;
 119 }
 120
 121 static int devices_delay(struct udev *udev, const char *syspath)
 122 {
 123         static const char *delay_device_list[] = {
 124                 "/block/md",
 125                 "/block/dm-",
 126                 NULL
 127         };
 128         size_t len;
 129         int i;
 130
 131         len = strlen(udev_get_sys_path(udev));
 132
 133         for (i = 0; delay_device_list[i] != NULL; i++) {
 134                 if (strstr(&syspath[len], delay_device_list[i]) != NULL) {
 135                         info(udev, "delaying: %s\n", syspath);
 136                         return 1;
 137                 }
 138         }
 139         return 0;
 140 }
 141
 142 /**
 143  * udev_enumerate_new_from_subsystems:
 144  * @udev: udev library context
 145  * @subsystem: the subsystem to enumerate
 146  *
 147  * Returns: an enumeration context
 148  **/
 149 struct udev_enumerate *udev_enumerate_new_from_subsystems(struct udev *udev, const char *subsystem)
 150 {
 151         struct udev_enumerate *udev_enumerate;
 152         char base[UTIL_PATH_SIZE];
 153         struct stat statbuf;
 154         struct udev_list *list;
 155
 156         if (udev == NULL)
 157                 return NULL;
 158
 159         udev_enumerate = malloc(sizeof(struct udev_enumerate));
 160         if (udev_enumerate == NULL)
 161                 return NULL;
 162         memset(udev_enumerate, 0x00, (sizeof(struct udev_enumerate)));
 163         udev_enumerate->refcount = 1;
 164         udev_enumerate->udev = udev;
 165         INIT_LIST_HEAD(&udev_enumerate->devices_list);
 166
 167         /* if we have /sys/subsystem/, forget all the old stuff */
 168         util_strlcpy(base, udev_get_sys_path(udev), sizeof(base));
 169         util_strlcat(base, "/subsystem", sizeof(base));
 170         if (stat(base, &statbuf) == 0) {
 171                 devices_scan_subsystems(udev, "/subsystem", subsystem, "/devices", &udev_enumerate->devices_list);
 172         } else {
 173                 devices_scan_subsystems(udev, "/bus", subsystem, "/devices", &udev_enumerate->devices_list);
 174                 devices_scan_subsystems(udev, "/class", subsystem, NULL, &udev_enumerate->devices_list);
 175         }
 176
 177         /* sort delayed devices to the end of the list */
 178         list = list_get_entry(&udev_enumerate->devices_list);
 179         while (list != NULL) {
 180                 if (devices_delay(udev, udev_list_get_name(list)))
 181                         list_move_to_end(list, &udev_enumerate->devices_list);
 182                 list = udev_list_get_next(list);
 183         }
 184         return udev_enumerate;
 185 }