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 static int devices_call(struct udev *udev, const char *syspath,
 113                         int (*cb)(struct udev *udev,
 114                                   const char *syspath, const char *subsystem, const char *name,
 115                                   void *data),
 116                         void *data,
 117                         int *cb_rc)
 118 {
 119         char subsystem[UTIL_PATH_SIZE];
 120         const char *name;
 121
 122         name = strrchr(syspath, '/');
 123         if (name == NULL)
 124                 return -1;
 125         name++;
 126
 127         if (util_get_sys_subsystem(udev, syspath, subsystem, sizeof(subsystem)) < 2)
 128                 return -1;
 129         *cb_rc = cb(udev, syspath, subsystem, name, data);
 130         return 0;
 131 }
 132
 133 /**
 134  * udev_enumerate_devices:
 135  * @udev_device: udev device
 136  * @cb: function to be called for every property found
 137  * @data: data to be passed to the function
 138  *
 139  * Retrieve the property key/value pairs belonging to the
 140  * udev device. For every key/value pair, the passed function will be
 141  * called. If the function returns 1, remaning properties will be
 142  * ignored.
 143  *
 144  * Returns: the number of properties passed to the caller, or a negative value on error
 145  **/
 146 int udev_enumerate_devices(struct udev *udev, const char *subsystem,
 147                            int (*cb)(struct udev *udev,
 148                                      const char *syspath, const char *subsystem, const char *name, void *data),
 149                            void *data)
 150 {
 151         char base[UTIL_PATH_SIZE];
 152         struct stat statbuf;
 153         struct list_head device_list;
 154         struct util_name_entry *loop_device;
 155         struct util_name_entry *tmp_device;
 156         int cb_rc = 0;
 157         int count = 0;
 158
 159         INIT_LIST_HEAD(&device_list);
 160
 161         /* if we have /sys/subsystem/, forget all the old stuff */
 162         util_strlcpy(base, udev_get_sys_path(udev), sizeof(base));
 163         util_strlcat(base, "/subsystem", sizeof(base));
 164         if (stat(base, &statbuf) == 0) {
 165                 devices_scan_subsystems(udev, "/subsystem", subsystem, "/devices", &device_list);
 166         } else {
 167                 devices_scan_subsystems(udev, "/bus", subsystem, "/devices", &device_list);
 168                 devices_scan_subsystems(udev, "/class", subsystem, NULL, &device_list);
 169         }
 170
 171         list_for_each_entry_safe(loop_device, tmp_device, &device_list, node) {
 172                 if (devices_delay(udev, loop_device->name))
 173                         continue;
 174                 if (cb_rc == 0)
 175                         if (devices_call(udev, loop_device->name, cb, data, &cb_rc) == 0)
 176                                 count++;
 177                 list_del(&loop_device->node);
 178                 free(loop_device->name);
 179                 free(loop_device);
 180         }
 181
 182         /* handle remaining delayed devices */
 183         list_for_each_entry_safe(loop_device, tmp_device, &device_list, node) {
 184                 if (cb_rc == 0)
 185                         if (devices_call(udev, loop_device->name, cb, data, &cb_rc) == 0)
 186                                 count++;
 187                 list_del(&loop_device->node);
 188                 free(loop_device->name);
 189                 free(loop_device);
 190         }
 191
 192         return count;
 193 }