2 * libudev - interface to udev device information
4 * Copyright (C) 2008 Kay Sievers <kay.sievers@vrfy.org>
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.
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.
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/>.
28 #include <sys/socket.h>
30 #include <linux/netlink.h>
33 #include "libudev-private.h"
39 struct sockaddr_nl snl;
40 struct sockaddr_un sun;
45 * udev_monitor_new_from_socket:
46 * @udev: udev library context
47 * @socket_path: unix socket path
49 * Create new udev monitor, setup and connect to a specified socket. The
50 * path to a socket can point to an existing socket file, or it will be
51 * created if needed. If neccessary, the permissions adjustment as well as
52 * the later cleanup of the socket file, needs to be done by the caller.
53 * If the socket path starts with a '@' character, an abstract namespace
54 * socket will be used.
56 * The initial refcount is 1, and needs to be decremented to
57 * release the ressources of the udev monitor.
59 * Returns: a new udev monitor, or #NULL, in case of an error
61 struct udev_monitor *udev_monitor_new_from_socket(struct udev *udev, const char *socket_path)
63 struct udev_monitor *udev_monitor;
68 if (socket_path == NULL)
70 udev_monitor = malloc(sizeof(struct udev_monitor));
71 if (udev_monitor == NULL)
73 memset(udev_monitor, 0x00, sizeof(struct udev_monitor));
74 udev_monitor->refcount = 1;
75 udev_monitor->udev = udev;
77 udev_monitor->sun.sun_family = AF_LOCAL;
78 if (socket_path[0] == '@') {
79 /* translate leading '@' to abstract namespace */
80 util_strlcpy(udev_monitor->sun.sun_path, socket_path, sizeof(udev_monitor->sun.sun_path));
81 udev_monitor->sun.sun_path[0] = '\0';
82 udev_monitor->addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(socket_path);
83 } else if (stat(socket_path, &statbuf) == 0 && S_ISSOCK(statbuf.st_mode)) {
84 /* existing socket file */
85 util_strlcpy(udev_monitor->sun.sun_path, socket_path, sizeof(udev_monitor->sun.sun_path));
86 udev_monitor->addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(socket_path);
88 /* no socket file, assume abstract namespace socket */
89 util_strlcpy(&udev_monitor->sun.sun_path[1], socket_path, sizeof(udev_monitor->sun.sun_path)-1);
90 udev_monitor->addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(socket_path)+1;
92 udev_monitor->sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
93 if (udev_monitor->sock == -1) {
94 err(udev, "error getting socket: %m\n");
98 info(udev, "monitor %p created with '%s'\n", udev_monitor, socket_path);
102 struct udev_monitor *udev_monitor_new_from_netlink(struct udev *udev)
104 struct udev_monitor *udev_monitor;
108 udev_monitor = malloc(sizeof(struct udev_monitor));
109 if (udev_monitor == NULL)
111 memset(udev_monitor, 0x00, sizeof(struct udev_monitor));
112 udev_monitor->refcount = 1;
113 udev_monitor->udev = udev;
115 udev_monitor->sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
116 if (udev_monitor->sock == -1) {
117 err(udev, "error getting socket: %m\n");
122 udev_monitor->snl.nl_family = AF_NETLINK;
123 udev_monitor->snl.nl_pid = getpid();
124 udev_monitor->snl.nl_groups = 1;
126 info(udev, "monitor %p created with NETLINK_KOBJECT_UEVENT\n", udev_monitor);
130 int udev_monitor_enable_receiving(struct udev_monitor *udev_monitor)
135 if (udev_monitor->snl.nl_family != 0) {
136 err = bind(udev_monitor->sock, (struct sockaddr *)&udev_monitor->snl, sizeof(struct sockaddr_nl));
138 err(udev_monitor->udev, "bind failed: %m\n");
141 info(udev_monitor->udev, "monitor %p listening on netlink\n", udev_monitor);
142 } else if (udev_monitor->sun.sun_family != 0) {
143 err = bind(udev_monitor->sock, (struct sockaddr *)&udev_monitor->sun, udev_monitor->addrlen);
145 err(udev_monitor->udev, "bind failed: %m\n");
148 /* enable receiving of the sender credentials */
149 setsockopt(udev_monitor->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
150 info(udev_monitor->udev, "monitor %p listening on socket\n", udev_monitor);
157 * @udev_monitor: udev monitor
159 * Take a reference of a udev monitor.
161 * Returns: the passed udev monitor
163 struct udev_monitor *udev_monitor_ref(struct udev_monitor *udev_monitor)
165 if (udev_monitor == NULL)
167 udev_monitor->refcount++;
172 * udev_monitor_unref:
173 * @udev_monitor: udev monitor
175 * Drop a reference ofa udev monitor. If the refcount reaches zero,
176 * the bound socket will be closed, and the ressources of the monitor
180 void udev_monitor_unref(struct udev_monitor *udev_monitor)
182 if (udev_monitor == NULL)
184 udev_monitor->refcount--;
185 if (udev_monitor->refcount > 0)
187 if (udev_monitor->sock >= 0)
188 close(udev_monitor->sock);
189 info(udev_monitor->udev, "monitor %p released\n", udev_monitor);
194 * udev_monitor_get_udev:
195 * @udev_monitor: udev monitor
197 * Retrieve the udev library context the monitor was created with.
199 * Returns: the udev library context
201 struct udev *udev_monitor_get_udev(struct udev_monitor *udev_monitor)
203 if (udev_monitor == NULL)
205 return udev_monitor->udev;
209 * udev_monitor_get_fd:
210 * @udev_monitor: udev monitor
212 * Retrieve the socket file descriptor associated with the monitor.
214 * Returns: the socket file descriptor
216 int udev_monitor_get_fd(struct udev_monitor *udev_monitor)
218 if (udev_monitor == NULL)
220 return udev_monitor->sock;
224 * udev_monitor_receive_device:
225 * @udev_monitor: udev monitor
227 * Receive data from the udev monitor socket, allocate a new udev
228 * device, fill in the received data, and return the device.
230 * Only socket connections with uid=0 are accepted. The caller
231 * needs to make sure, that there is data to read from the socket,
232 * the call will block until the socket becomes readable.
234 * The initial refcount is 1, and needs to be decremented to
235 * release the ressources of the udev device.
237 * Returns: a new udev device, or #NULL, in case of an error
239 struct udev_device *udev_monitor_receive_device(struct udev_monitor *udev_monitor)
241 struct udev_device *udev_device;
244 char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
248 int subsystem_set = 0;
253 if (udev_monitor == NULL)
255 memset(buf, 0x00, sizeof(buf));
257 iov.iov_len = sizeof(buf);
258 memset (&smsg, 0x00, sizeof(struct msghdr));
261 smsg.msg_control = cred_msg;
262 smsg.msg_controllen = sizeof(cred_msg);
264 if (recvmsg(udev_monitor->sock, &smsg, 0) < 0) {
266 info(udev_monitor->udev, "unable to receive message");
270 if (udev_monitor->sun.sun_family != 0) {
271 struct cmsghdr *cmsg = CMSG_FIRSTHDR(&smsg);
272 struct ucred *cred = (struct ucred *)CMSG_DATA (cmsg);
274 if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
275 info(udev_monitor->udev, "no sender credentials received, message ignored");
279 if (cred->uid != 0) {
280 info(udev_monitor->udev, "sender uid=%d, message ignored", cred->uid);
286 bufpos = strlen(buf) + 1;
287 if (bufpos < sizeof("a@/d") || bufpos >= sizeof(buf)) {
288 info(udev_monitor->udev, "invalid message length");
292 /* check message header */
293 if (strstr(buf, "@/") == NULL) {
294 info(udev_monitor->udev, "unrecognized message header");
298 udev_device = device_new(udev_monitor->udev);
299 if (udev_device == NULL) {
303 while (bufpos < sizeof(buf)) {
308 keylen = strlen(key);
311 bufpos += keylen + 1;
313 if (strncmp(key, "DEVPATH=", 8) == 0) {
314 char path[UTIL_PATH_SIZE];
316 util_strlcpy(path, udev_get_sys_path(udev_monitor->udev), sizeof(path));
317 util_strlcat(path, &key[8], sizeof(path));
318 udev_device_set_syspath(udev_device, path);
320 } else if (strncmp(key, "SUBSYSTEM=", 10) == 0) {
321 udev_device_set_subsystem(udev_device, &key[10]);
323 } else if (strncmp(key, "DEVNAME=", 8) == 0) {
324 udev_device_set_devnode(udev_device, &key[8]);
325 } else if (strncmp(key, "DEVLINKS=", 9) == 0) {
326 char devlinks[UTIL_PATH_SIZE];
330 util_strlcpy(devlinks, &key[9], sizeof(devlinks));
332 next = strchr(slink, ' ');
333 while (next != NULL) {
335 udev_device_add_devlink(udev_device, slink);
337 next = strchr(slink, ' ');
339 if (slink[0] != '\0')
340 udev_device_add_devlink(udev_device, slink);
341 } else if (strncmp(key, "DRIVER=", 7) == 0) {
342 udev_device_set_driver(udev_device, &key[7]);
343 } else if (strncmp(key, "ACTION=", 7) == 0) {
344 udev_device_set_action(udev_device, &key[7]);
346 } else if (strncmp(key, "MAJOR=", 6) == 0) {
347 maj = strtoull(&key[6], NULL, 10);
348 } else if (strncmp(key, "MINOR=", 6) == 0) {
349 min = strtoull(&key[6], NULL, 10);
350 } else if (strncmp(key, "DEVPATH_OLD=", 12) == 0) {
351 udev_device_set_devpath_old(udev_device, &key[12]);
352 } else if (strncmp(key, "PHYSDEVPATH=", 12) == 0) {
353 udev_device_set_physdevpath(udev_device, &key[12]);
354 } else if (strncmp(key, "SEQNUM=", 7) == 0) {
355 udev_device_set_seqnum(udev_device, strtoull(&key[7], NULL, 10));
356 } else if (strncmp(key, "TIMEOUT=", 8) == 0) {
357 udev_device_set_timeout(udev_device, strtoull(&key[8], NULL, 10));
358 } else if (strncmp(key, "PHYSDEV", 7) == 0) {
359 /* skip deprecated values */
362 udev_device_add_property_from_string(udev_device, key);
365 if (!devpath_set || !subsystem_set || !action_set) {
366 info(udev_monitor->udev, "missing values, skip\n");
367 udev_device_unref(udev_device);
370 udev_device_set_devnum(udev_device, makedev(maj, min));
371 udev_device_set_info_loaded(udev_device);
375 int udev_monitor_send_device(struct udev_monitor *udev_monitor, struct udev_device *udev_device)
378 struct udev_list_entry *list_entry;
383 action = udev_device_get_action(udev_device);
386 bufpos = snprintf(buf, sizeof(buf), "%s@%s", action, udev_device_get_devpath(udev_device));
388 udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(udev_device)) {
389 bufpos += snprintf(&buf[bufpos], sizeof(buf) - bufpos, "%s=%s",
390 udev_list_entry_get_name(list_entry),
391 udev_list_entry_get_value(list_entry));
394 count = sendto(udev_monitor->sock,
396 (struct sockaddr *)&udev_monitor->sun, udev_monitor->addrlen);
397 info(udev_monitor->udev, "passed %zi bytes to monitor %p, \n", count, udev_monitor);