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 "config.h"
  21
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <stddef.h>
  25 #include <unistd.h>
  26 #include <errno.h>
  27 #include <string.h>
  28 #include <dirent.h>
  29 #include <sys/stat.h>
  30
  31 #include "libudev.h"
  32 #include "libudev-private.h"
  33
  34 static int devices_scan_subsystem(struct udev *udev,
  35                                   const char *basedir, const char *subsystem, const char *subdir,
  36                                   struct list_head *device_list)
  37 {
  38         char path[UTIL_PATH_SIZE];
  39         DIR *dir;
  40         struct dirent *dent;
  41
  42         util_strlcpy(path, udev_get_sys_path(udev), sizeof(path));
  43         util_strlcat(path, basedir, sizeof(path));
  44         util_strlcat(path, "/", sizeof(path));
  45         util_strlcat(path, subsystem, sizeof(path));
  46         if (subdir != NULL)
  47                 util_strlcat(path, subdir, sizeof(path));
  48         dir = opendir(path);
  49         if (dir == NULL)
  50                 return -1;
  51         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
  52                 char syspath[UTIL_PATH_SIZE];
  53
  54                 if (dent->d_name[0] == '.')
  55                         continue;
  56                 util_strlcpy(syspath, path, sizeof(syspath));
  57                 util_strlcat(syspath, "/", sizeof(syspath));
  58                 util_strlcat(syspath, dent->d_name, sizeof(syspath));
  59                 util_resolve_sys_link(udev, syspath, sizeof(syspath));
  60                 util_name_list_add(udev, device_list, syspath, NULL, 1);
  61         }
  62         closedir(dir);
  63         return 0;
  64 }
  65
  66 static int devices_scan_subsystems(struct udev *udev,
  67                                    const char *basedir, const char *subsystem, const char *subdir,
  68                                    struct list_head *device_list)
  69 {
  70         char path[UTIL_PATH_SIZE];
  71         DIR *dir;
  72         struct dirent *dent;
  73
  74         if (subsystem != NULL)
  75                 return devices_scan_subsystem(udev, basedir, subsystem, subdir, device_list);
  76
  77         util_strlcpy(path, udev_get_sys_path(udev), sizeof(path));
  78         util_strlcat(path, basedir, sizeof(path));
  79         dir = opendir(path);
  80         if (dir == NULL)
  81                 return -1;
  82         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
  83                 if (dent->d_name[0] == '.')
  84                         continue;
  85                 devices_scan_subsystem(udev, basedir, dent->d_name, subdir, device_list);
  86         }
  87         closedir(dir);
  88         return 0;
  89 }
  90
  91 static int devices_delay(struct udev *udev, const char *syspath)
  92 {
  93         static const char *delay_device_list[] = {
  94                 "/block/md",
  95                 "/block/dm-",
  96                 NULL
  97         };
  98         size_t len;
  99         int i;
 100
 101         len = strlen(udev_get_sys_path(udev));
 102
 103         for (i = 0; delay_device_list[i] != NULL; i++) {
 104                 if (strstr(&syspath[len], delay_device_list[i]) != NULL) {
 105                         info(udev, "delaying: %s\n", syspath);
 106                         return 1;
 107                 }
 108         }
 109         return 0;
 110 }
 111
 112 /**
 113  * udev_enumerate_devices:
 114  * @udev: udev library context
 115  * @subsystem: the subsystem to enumerate
 116  * @cb: function to be called for every device found
 117  * @data: data to be passed to the function
 118  *
 119  * Returns: the number of devices passed to the caller, or a negative value on error
 120  **/
 121 int udev_enumerate_devices(struct udev *udev, const char *subsystem,
 122                            int (*cb)(struct udev_device *udev_device, void *data),
 123                            void *data)
 124 {
 125         char base[UTIL_PATH_SIZE];
 126         struct stat statbuf;
 127         struct list_head device_list;
 128         struct util_name_entry *loop_device;
 129         struct util_name_entry *tmp_device;
 130         int cb_rc = 0;
 131         int count = 0;
 132
 133         INIT_LIST_HEAD(&device_list);
 134
 135         /* if we have /sys/subsystem/, forget all the old stuff */
 136         util_strlcpy(base, udev_get_sys_path(udev), sizeof(base));
 137         util_strlcat(base, "/subsystem", sizeof(base));
 138         if (stat(base, &statbuf) == 0) {
 139                 devices_scan_subsystems(udev, "/subsystem", subsystem, "/devices", &device_list);
 140         } else {
 141                 devices_scan_subsystems(udev, "/bus", subsystem, "/devices", &device_list);
 142                 devices_scan_subsystems(udev, "/class", subsystem, NULL, &device_list);
 143         }
 144
 145         list_for_each_entry_safe(loop_device, tmp_device, &device_list, node) {
 146                 if (devices_delay(udev, loop_device->name))
 147                         continue;
 148                 if (cb_rc == 0) {
 149                         struct udev_device *device;
 150
 151                         device = udev_device_new_from_syspath(udev, loop_device->name);
 152                         if (device != NULL) {
 153                                 cb_rc = cb(device, data);
 154                                 count++;
 155                                 udev_device_unref(device);
 156                         }
 157                 }
 158                 list_del(&loop_device->node);
 159                 free(loop_device->name);
 160                 free(loop_device);
 161         }
 162
 163         /* handle remaining delayed devices */
 164         list_for_each_entry_safe(loop_device, tmp_device, &device_list, node) {
 165                 if (cb_rc == 0) {
 166                         struct udev_device *device;
 167
 168                         device = udev_device_new_from_syspath(udev, loop_device->name);
 169                         if (device != NULL) {
 170                                 cb_rc = cb(device, data);
 171                                 count++;
 172                                 udev_device_unref(device);
 173                         }
 174                 }
 175                 list_del(&loop_device->node);
 176                 free(loop_device->name);
 177                 free(loop_device);
 178         }
 179
 180         return count;
 181 }