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 resources 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 = calloc(1, sizeof(struct udev_monitor));
71 if (udev_monitor == NULL)
73 udev_monitor->refcount = 1;
74 udev_monitor->udev = udev;
76 udev_monitor->sun.sun_family = AF_LOCAL;
77 if (socket_path[0] == '@') {
78 /* translate leading '@' to abstract namespace */
79 util_strlcpy(udev_monitor->sun.sun_path, socket_path, sizeof(udev_monitor->sun.sun_path));
80 udev_monitor->sun.sun_path[0] = '\0';
81 udev_monitor->addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(socket_path);
82 } else if (stat(socket_path, &statbuf) == 0 && S_ISSOCK(statbuf.st_mode)) {
83 /* existing socket file */
84 util_strlcpy(udev_monitor->sun.sun_path, socket_path, sizeof(udev_monitor->sun.sun_path));
85 udev_monitor->addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(socket_path);
87 /* no socket file, assume abstract namespace socket */
88 util_strlcpy(&udev_monitor->sun.sun_path[1], socket_path, sizeof(udev_monitor->sun.sun_path)-1);
89 udev_monitor->addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(socket_path)+1;
91 udev_monitor->sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
92 if (udev_monitor->sock == -1) {
93 err(udev, "error getting socket: %m\n");
97 dbg(udev, "monitor %p created with '%s'\n", udev_monitor, socket_path);
101 struct udev_monitor *udev_monitor_new_from_netlink(struct udev *udev)
103 struct udev_monitor *udev_monitor;
107 udev_monitor = calloc(1, sizeof(struct udev_monitor));
108 if (udev_monitor == NULL)
110 udev_monitor->refcount = 1;
111 udev_monitor->udev = udev;
113 udev_monitor->sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
114 if (udev_monitor->sock == -1) {
115 err(udev, "error getting socket: %m\n");
120 udev_monitor->snl.nl_family = AF_NETLINK;
121 udev_monitor->snl.nl_pid = getpid();
122 udev_monitor->snl.nl_groups = 1;
124 dbg(udev, "monitor %p created with NETLINK_KOBJECT_UEVENT\n", udev_monitor);
128 int udev_monitor_enable_receiving(struct udev_monitor *udev_monitor)
133 if (udev_monitor->snl.nl_family != 0) {
134 err = bind(udev_monitor->sock, (struct sockaddr *)&udev_monitor->snl, sizeof(struct sockaddr_nl));
136 err(udev_monitor->udev, "bind failed: %m\n");
139 dbg(udev_monitor->udev, "monitor %p listening on netlink\n", udev_monitor);
140 } else if (udev_monitor->sun.sun_family != 0) {
141 err = bind(udev_monitor->sock, (struct sockaddr *)&udev_monitor->sun, udev_monitor->addrlen);
143 err(udev_monitor->udev, "bind failed: %m\n");
146 /* enable receiving of the sender credentials */
147 setsockopt(udev_monitor->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
148 dbg(udev_monitor->udev, "monitor %p listening on socket\n", udev_monitor);
153 int udev_monitor_set_receive_buffer_size(struct udev_monitor *udev_monitor, int size)
155 if (udev_monitor == NULL)
157 return setsockopt(udev_monitor->sock, SOL_SOCKET, SO_RCVBUFFORCE, &size, sizeof(size));
162 * @udev_monitor: udev monitor
164 * Take a reference of a udev monitor.
166 * Returns: the passed udev monitor
168 struct udev_monitor *udev_monitor_ref(struct udev_monitor *udev_monitor)
170 if (udev_monitor == NULL)
172 udev_monitor->refcount++;
177 * udev_monitor_unref:
178 * @udev_monitor: udev monitor
180 * Drop a reference ofa udev monitor. If the refcount reaches zero,
181 * the bound socket will be closed, and the resources of the monitor
185 void udev_monitor_unref(struct udev_monitor *udev_monitor)
187 if (udev_monitor == NULL)
189 udev_monitor->refcount--;
190 if (udev_monitor->refcount > 0)
192 if (udev_monitor->sock >= 0)
193 close(udev_monitor->sock);
194 dbg(udev_monitor->udev, "monitor %p released\n", udev_monitor);
199 * udev_monitor_get_udev:
200 * @udev_monitor: udev monitor
202 * Retrieve the udev library context the monitor was created with.
204 * Returns: the udev library context
206 struct udev *udev_monitor_get_udev(struct udev_monitor *udev_monitor)
208 if (udev_monitor == NULL)
210 return udev_monitor->udev;
214 * udev_monitor_get_fd:
215 * @udev_monitor: udev monitor
217 * Retrieve the socket file descriptor associated with the monitor.
219 * Returns: the socket file descriptor
221 int udev_monitor_get_fd(struct udev_monitor *udev_monitor)
223 if (udev_monitor == NULL)
225 return udev_monitor->sock;
229 * udev_monitor_receive_device:
230 * @udev_monitor: udev monitor
232 * Receive data from the udev monitor socket, allocate a new udev
233 * device, fill in the received data, and return the device.
235 * Only socket connections with uid=0 are accepted. The caller
236 * needs to make sure that there is data to read from the socket.
237 * The call will block until the socket becomes readable.
239 * The initial refcount is 1, and needs to be decremented to
240 * release the resources of the udev device.
242 * Returns: a new udev device, or #NULL, in case of an error
244 struct udev_device *udev_monitor_receive_device(struct udev_monitor *udev_monitor)
246 struct udev_device *udev_device;
249 char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
253 int subsystem_set = 0;
258 if (udev_monitor == NULL)
260 memset(buf, 0x00, sizeof(buf));
262 iov.iov_len = sizeof(buf);
263 memset (&smsg, 0x00, sizeof(struct msghdr));
266 smsg.msg_control = cred_msg;
267 smsg.msg_controllen = sizeof(cred_msg);
269 if (recvmsg(udev_monitor->sock, &smsg, 0) < 0) {
271 info(udev_monitor->udev, "unable to receive message");
275 if (udev_monitor->sun.sun_family != 0) {
276 struct cmsghdr *cmsg = CMSG_FIRSTHDR(&smsg);
277 struct ucred *cred = (struct ucred *)CMSG_DATA (cmsg);
279 if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
280 info(udev_monitor->udev, "no sender credentials received, message ignored");
284 if (cred->uid != 0) {
285 info(udev_monitor->udev, "sender uid=%d, message ignored", cred->uid);
291 bufpos = strlen(buf) + 1;
292 if (bufpos < sizeof("a@/d") || bufpos >= sizeof(buf)) {
293 info(udev_monitor->udev, "invalid message length");
297 /* check message header */
298 if (strstr(buf, "@/") == NULL) {
299 info(udev_monitor->udev, "unrecognized message header");
303 udev_device = device_new(udev_monitor->udev);
304 if (udev_device == NULL) {
308 while (bufpos < sizeof(buf)) {
313 keylen = strlen(key);
316 bufpos += keylen + 1;
318 if (strncmp(key, "DEVPATH=", 8) == 0) {
319 char path[UTIL_PATH_SIZE];
321 util_strlcpy(path, udev_get_sys_path(udev_monitor->udev), sizeof(path));
322 util_strlcat(path, &key[8], sizeof(path));
323 udev_device_set_syspath(udev_device, path);
325 } else if (strncmp(key, "SUBSYSTEM=", 10) == 0) {
326 udev_device_set_subsystem(udev_device, &key[10]);
328 } else if (strncmp(key, "DEVTYPE=", 8) == 0) {
329 udev_device_set_devtype(udev_device, &key[8]);
330 } else if (strncmp(key, "DEVNAME=", 8) == 0) {
331 udev_device_set_devnode(udev_device, &key[8]);
332 } else if (strncmp(key, "DEVLINKS=", 9) == 0) {
333 char devlinks[UTIL_PATH_SIZE];
337 util_strlcpy(devlinks, &key[9], sizeof(devlinks));
339 next = strchr(slink, ' ');
340 while (next != NULL) {
342 udev_device_add_devlink(udev_device, slink);
344 next = strchr(slink, ' ');
346 if (slink[0] != '\0')
347 udev_device_add_devlink(udev_device, slink);
348 } else if (strncmp(key, "DRIVER=", 7) == 0) {
349 udev_device_set_driver(udev_device, &key[7]);
350 } else if (strncmp(key, "ACTION=", 7) == 0) {
351 udev_device_set_action(udev_device, &key[7]);
353 } else if (strncmp(key, "MAJOR=", 6) == 0) {
354 maj = strtoull(&key[6], NULL, 10);
355 } else if (strncmp(key, "MINOR=", 6) == 0) {
356 min = strtoull(&key[6], NULL, 10);
357 } else if (strncmp(key, "DEVPATH_OLD=", 12) == 0) {
358 udev_device_set_devpath_old(udev_device, &key[12]);
359 } else if (strncmp(key, "PHYSDEVPATH=", 12) == 0) {
360 udev_device_set_physdevpath(udev_device, &key[12]);
361 } else if (strncmp(key, "SEQNUM=", 7) == 0) {
362 udev_device_set_seqnum(udev_device, strtoull(&key[7], NULL, 10));
363 } else if (strncmp(key, "TIMEOUT=", 8) == 0) {
364 udev_device_set_timeout(udev_device, strtoull(&key[8], NULL, 10));
365 } else if (strncmp(key, "PHYSDEV", 7) == 0) {
366 /* skip deprecated values */
369 udev_device_add_property_from_string(udev_device, key);
372 if (!devpath_set || !subsystem_set || !action_set) {
373 info(udev_monitor->udev, "missing values, skip\n");
374 udev_device_unref(udev_device);
378 udev_device_set_devnum(udev_device, makedev(maj, min));
379 udev_device_set_info_loaded(udev_device);
383 int udev_monitor_send_device(struct udev_monitor *udev_monitor, struct udev_device *udev_device)
389 len = udev_device_get_properties_monitor_buf(udev_device, &buf);
392 count = sendto(udev_monitor->sock,
394 (struct sockaddr *)&udev_monitor->sun, udev_monitor->addrlen);
395 info(udev_monitor->udev, "passed %zi bytes to monitor %p, \n", count, udev_monitor);