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         size_t len;
  42
  43         len = util_strlcpy(path, udev_get_sys_path(udev), sizeof(path));
  44         util_strlcat(path, basedir, sizeof(path));
  45         util_strlcat(path, "/", sizeof(path));
  46         util_strlcat(path, subsystem, sizeof(path));
  47         if (subdir != NULL)
  48                 util_strlcat(path, subdir, sizeof(path));
  49         dir = opendir(path);
  50         if (dir == NULL)
  51                 return -1;
  52         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
  53                 char devpath[UTIL_PATH_SIZE];
  54
  55                 if (dent->d_name[0] == '.')
  56                         continue;
  57                 util_strlcpy(devpath, &path[len], sizeof(devpath));
  58                 util_strlcat(devpath, "/", sizeof(devpath));
  59                 util_strlcat(devpath, dent->d_name, sizeof(devpath));
  60                 util_resolve_sys_link(udev, devpath, sizeof(devpath));
  61                 util_name_list_add(udev, device_list, devpath, NULL, 1);
  62         }
  63         closedir(dir);
  64         return 0;
  65 }
  66
  67 static int devices_scan_subsystems(struct udev *udev,
  68                                    const char *basedir, const char *subsystem, const char *subdir,
  69                                    struct list_head *device_list)
  70 {
  71         char path[UTIL_PATH_SIZE];
  72         DIR *dir;
  73         struct dirent *dent;
  74
  75         if (subsystem != NULL)
  76                 return devices_scan_subsystem(udev, basedir, subsystem, subdir, device_list);
  77
  78         util_strlcpy(path, udev_get_sys_path(udev), sizeof(path));
  79         util_strlcat(path, basedir, sizeof(path));
  80         dir = opendir(path);
  81         if (dir == NULL)
  82                 return -1;
  83         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
  84                 if (dent->d_name[0] == '.')
  85                         continue;
  86                 devices_scan_subsystem(udev, basedir, dent->d_name, subdir, device_list);
  87         }
  88         closedir(dir);
  89         return 0;
  90 }
  91
  92 static int devices_delay(struct udev *udev, const char *devpath)
  93 {
  94         static const char *delay_device_list[] = {
  95                 "/block/md",
  96                 "/block/dm-",
  97                 NULL
  98         };
  99         int i;
 100
 101         for (i = 0; delay_device_list[i] != NULL; i++) {
 102                 if (strstr(devpath, delay_device_list[i]) != NULL) {
 103                         info(udev, "delaying: %s\n", devpath);
 104                         return 1;
 105                 }
 106         }
 107         return 0;
 108 }
 109
 110 static int devices_call(struct udev *udev, const char *devpath,
 111                         int (*cb)(struct udev *udev,
 112                                   const char *devpath, const char *subsystem, const char *name,
 113                                   void *data),
 114                         void *data,
 115                         int *cb_rc)
 116 {
 117         char subsystem[UTIL_PATH_SIZE];
 118         const char *name;
 119
 120         name = strrchr(devpath, '/');
 121         if (name == NULL)
 122                 return -1;
 123         name++;
 124
 125         if (util_get_sys_subsystem(udev, devpath, subsystem, sizeof(subsystem)) < 2)
 126                 return -1;
 127         *cb_rc = cb(udev, devpath, subsystem, name, data);
 128         return 0;
 129 }
 130
 131 /**
 132  * udev_enumerate_devices:
 133  * @udev_device: udev device
 134  * @cb: function to be called for every property found
 135  * @data: data to be passed to the function
 136  *
 137  * Retrieve the property key/value pairs belonging to the
 138  * udev device. For every key/value pair, the passed function will be
 139  * called. If the function returns 1, remaning properties will be
 140  * ignored.
 141  *
 142  * Returns: the number of properties passed to the caller, or a negative value on error
 143  **/
 144 int udev_enumerate_devices(struct udev *udev, const char *subsystem,
 145                            int (*cb)(struct udev *udev,
 146                                      const char *devpath, const char *subsystem, const char *name, void *data),
 147                            void *data)
 148 {
 149         char base[UTIL_PATH_SIZE];
 150         struct stat statbuf;
 151         struct list_head device_list;
 152         struct util_name_entry *loop_device;
 153         struct util_name_entry *tmp_device;
 154         int cb_rc = 0;
 155         int count = 0;
 156
 157         INIT_LIST_HEAD(&device_list);
 158
 159         /* if we have /sys/subsystem/, forget all the old stuff */
 160         util_strlcpy(base, udev_get_sys_path(udev), sizeof(base));
 161         util_strlcat(base, "/subsystem", sizeof(base));
 162         if (stat(base, &statbuf) == 0) {
 163                 devices_scan_subsystems(udev, "/subsystem", subsystem, "/devices", &device_list);
 164         } else {
 165                 devices_scan_subsystems(udev, "/bus", subsystem, "/devices", &device_list);
 166                 devices_scan_subsystems(udev, "/class", subsystem, NULL, &device_list);
 167         }
 168
 169         list_for_each_entry_safe(loop_device, tmp_device, &device_list, node) {
 170                 if (devices_delay(udev, loop_device->name))
 171                         continue;
 172                 if (cb_rc == 0)
 173                         if (devices_call(udev, loop_device->name, cb, data, &cb_rc) == 0)
 174                                 count++;
 175                 list_del(&loop_device->node);
 176                 free(loop_device->name);
 177                 free(loop_device);
 178         }
 179
 180         /* handle remaining delayed devices */
 181         list_for_each_entry_safe(loop_device, tmp_device, &device_list, node) {
 182                 if (cb_rc == 0)
 183                         if (devices_call(udev, loop_device->name, cb, data, &cb_rc) == 0)
 184                                 count++;
 185                 list_del(&loop_device->node);
 186                 free(loop_device->name);
 187                 free(loop_device);
 188         }
 189
 190         return count;
 191 }