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 #include "../udev.h"
  34
  35 static int devices_scan_subsystem(struct udev *udev,
  36                                   const char *basedir, const char *subsystem, const char *subdir,
  37                                   struct list_head *device_list)
  38 {
  39         char path[PATH_SIZE];
  40         DIR *dir;
  41         struct dirent *dent;
  42         size_t len;
  43
  44         len = strlcpy(path, udev_get_sys_path(udev), sizeof(path));
  45         strlcat(path, basedir, sizeof(path));
  46         strlcat(path, "/", sizeof(path));
  47         strlcat(path, subsystem, sizeof(path));
  48         if (subdir != NULL)
  49                 strlcat(path, subdir, sizeof(path));
  50         dir = opendir(path);
  51         if (dir == NULL)
  52                 return -1;
  53         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
  54                 char devpath[PATH_SIZE];
  55
  56                 if (dent->d_name[0] == '.')
  57                         continue;
  58                 strlcpy(devpath, &path[len], sizeof(devpath));
  59                 strlcat(devpath, "/", sizeof(devpath));
  60                 strlcat(devpath, dent->d_name, sizeof(devpath));
  61                 sysfs_resolve_link(udev, devpath, sizeof(devpath));
  62                 name_list_add(udev, device_list, devpath, 1);
  63         }
  64         closedir(dir);
  65         return 0;
  66 }
  67
  68 static int devices_scan_subsystems(struct udev *udev,
  69                                    const char *basedir, const char *subsystem, const char *subdir,
  70                                    struct list_head *device_list)
  71 {
  72         char path[PATH_SIZE];
  73         DIR *dir;
  74         struct dirent *dent;
  75
  76         if (subsystem != NULL)
  77                 return devices_scan_subsystem(udev, basedir, subsystem, subdir, device_list);
  78
  79         strlcpy(path, udev_get_sys_path(udev), sizeof(path));
  80         strlcat(path, basedir, sizeof(path));
  81         dir = opendir(path);
  82         if (dir == NULL)
  83                 return -1;
  84         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
  85                 if (dent->d_name[0] == '.')
  86                         continue;
  87                 devices_scan_subsystem(udev, basedir, dent->d_name, subdir, device_list);
  88         }
  89         closedir(dir);
  90         return 0;
  91 }
  92
  93 static int devices_delay(struct udev *udev, const char *devpath)
  94 {
  95         static const char *delay_device_list[] = {
  96                 "/block/md",
  97                 "/block/dm-",
  98                 NULL
  99         };
 100         int i;
 101
 102         for (i = 0; delay_device_list[i] != NULL; i++) {
 103                 if (strstr(devpath, delay_device_list[i]) != NULL) {
 104                         info(udev, "delaying: %s\n", devpath);
 105                         return 1;
 106                 }
 107         }
 108         return 0;
 109 }
 110
 111 static int devices_call(struct udev *udev, const char *devpath,
 112                         int (*cb)(struct udev *udev,
 113                                   const char *devpath, const char *subsystem, const char *name,
 114                                   void *data),
 115                         void *data,
 116                         int *cb_rc)
 117 {
 118         char subsystem[NAME_SIZE];
 119         const char *name;
 120
 121         name = strrchr(devpath, '/');
 122         if (name == NULL)
 123                 return -1;
 124         name++;
 125
 126         if (util_get_sys_subsystem(udev, devpath, subsystem, sizeof(subsystem)) < 2)
 127                 return -1;
 128         *cb_rc = cb(udev, devpath, subsystem, name, data);
 129         return 0;
 130 }
 131
 132 /**
 133  * udev_devices_enumerate:
 134  * @udev_device: udev device
 135  * @cb: function to be called for every property found
 136  * @data: data to be passed to the function
 137  *
 138  * Retrieve the property key/value pairs belonging to the
 139  * udev device. For every key/value pair, the passed function will be
 140  * called. If the function returns 1, remaning properties will be
 141  * ignored.
 142  *
 143  * Returns: the number of properties passed to the caller, or a negative value on error
 144  **/
 145 int udev_devices_enumerate(struct udev *udev, const char *subsystem,
 146                            int (*cb)(struct udev *udev,
 147                                      const char *devpath, const char *subsystem, const char *name, void *data),
 148                            void *data)
 149 {
 150         char base[PATH_SIZE];
 151         struct stat statbuf;
 152         struct list_head device_list;
 153         struct name_entry *loop_device;
 154         struct name_entry *tmp_device;
 155         int cb_rc = 0;
 156         int count = 0;
 157
 158         INIT_LIST_HEAD(&device_list);
 159
 160         /* if we have /sys/subsystem/, forget all the old stuff */
 161         strlcpy(base, udev_get_sys_path(udev), sizeof(base));
 162         strlcat(base, "/subsystem", sizeof(base));
 163         if (stat(base, &statbuf) == 0) {
 164                 devices_scan_subsystems(udev, "/subsystem", subsystem, "/devices", &device_list);
 165         } else {
 166                 devices_scan_subsystems(udev, "/bus", subsystem, "/devices", &device_list);
 167                 devices_scan_subsystems(udev, "/class", subsystem, NULL, &device_list);
 168         }
 169
 170         list_for_each_entry_safe(loop_device, tmp_device, &device_list, node) {
 171                 if (devices_delay(udev, loop_device->name))
 172                         continue;
 173                 if (cb_rc == 0)
 174                         if (devices_call(udev, loop_device->name, cb, data, &cb_rc) == 0)
 175                                 count++;
 176                 list_del(&loop_device->node);
 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);
 187         }
 188
 189         return count;
 190 }