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/>.
30 #include <sys/socket.h>
32 #include <linux/netlink.h>
35 #include "libudev-private.h"
42 struct sockaddr_nl snl;
43 struct sockaddr_un sun;
48 * udev_monitor_new_from_socket:
49 * @udev: udev library context
50 * @socket_path: unix socket path
52 * Create new udev monitor, setup and connect to a specified socket. The
53 * path to a socket can point to an existing socket file, or it will be
54 * created if needed. If neccessary, the permissions adjustment as well as
55 * the later cleanup of the socket file, needs to be done by the caller.
56 * If the socket path starts with a '@' character, an abstract namespace
57 * socket will be used.
59 * The initial refcount is 1, and needs to be decremented to
60 * release the ressources of the udev monitor.
62 * Returns: a new udev monitor, or #NULL, in case of an error
64 struct udev_monitor *udev_monitor_new_from_socket(struct udev *udev, const char *socket_path)
66 struct udev_monitor *udev_monitor;
70 if (socket_path == NULL)
72 udev_monitor = malloc(sizeof(struct udev_monitor));
73 if (udev_monitor == NULL)
75 memset(udev_monitor, 0x00, sizeof(struct udev_monitor));
76 udev_monitor->refcount = 1;
77 udev_monitor->udev = udev;
79 udev_monitor->sun.sun_family = AF_LOCAL;
80 strcpy(udev_monitor->sun.sun_path, socket_path);
81 udev_monitor->addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(udev_monitor->sun.sun_path);
83 /* translate leading '@' to abstract namespace */
84 if (udev_monitor->sun.sun_path[0] == '@')
85 udev_monitor->sun.sun_path[0] = '\0';
87 udev_monitor->sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
88 if (udev_monitor->sock == -1) {
89 err(udev, "error getting socket: %s\n", strerror(errno));
93 info(udev, "monitor %p created with '%s'\n", udev_monitor, socket_path);
97 struct udev_monitor *udev_monitor_new_from_netlink(struct udev *udev)
99 struct udev_monitor *udev_monitor;
103 udev_monitor = malloc(sizeof(struct udev_monitor));
104 if (udev_monitor == NULL)
106 memset(udev_monitor, 0x00, sizeof(struct udev_monitor));
107 udev_monitor->refcount = 1;
108 udev_monitor->udev = udev;
110 udev_monitor->sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
111 if (udev_monitor->sock == -1) {
112 err(udev, "error getting socket: %s\n", strerror(errno));
117 udev_monitor->snl.nl_family = AF_NETLINK;
118 udev_monitor->snl.nl_pid = getpid();
119 udev_monitor->snl.nl_groups = 1;
121 info(udev, "monitor %p created with NETLINK_KOBJECT_UEVENT\n", udev_monitor);
125 int udev_monitor_enable_receiving(struct udev_monitor *udev_monitor)
130 if (udev_monitor->snl.nl_family != 0) {
131 err = bind(udev_monitor->sock, (struct sockaddr *)&udev_monitor->snl, sizeof(struct sockaddr_nl));
133 err(udev_monitor->udev, "bind failed: %s\n", strerror(errno));
136 info(udev_monitor->udev, "monitor %p listening on netlink\n", udev_monitor);
137 } else if (udev_monitor->sun.sun_family != 0) {
138 err = bind(udev_monitor->sock, (struct sockaddr *)&udev_monitor->sun, udev_monitor->addrlen);
140 err(udev_monitor->udev, "bind failed: %s\n", strerror(errno));
143 /* enable receiving of the sender credentials */
144 setsockopt(udev_monitor->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
145 info(udev_monitor->udev, "monitor %p listening on socket\n", udev_monitor);
152 * @udev_monitor: udev monitor
154 * Take a reference of a udev monitor.
156 * Returns: the passed udev monitor
158 struct udev_monitor *udev_monitor_ref(struct udev_monitor *udev_monitor)
160 if (udev_monitor == NULL)
162 udev_monitor->refcount++;
167 * udev_monitor_unref:
168 * @udev_monitor: udev monitor
170 * Drop a reference ofa udev monitor. If the refcount reaches zero,
171 * the bound socket will be closed, and the ressources of the monitor
175 void udev_monitor_unref(struct udev_monitor *udev_monitor)
177 if (udev_monitor == NULL)
179 udev_monitor->refcount--;
180 if (udev_monitor->refcount > 0)
182 if (udev_monitor->sock >= 0)
183 close(udev_monitor->sock);
184 info(udev_monitor->udev, "monitor %p released\n", udev_monitor);
189 * udev_monitor_get_udev:
190 * @udev_monitor: udev monitor
192 * Retrieve the udev library context the monitor was created with.
194 * Returns: the udev library context
196 struct udev *udev_monitor_get_udev(struct udev_monitor *udev_monitor)
198 if (udev_monitor == NULL)
200 return udev_monitor->udev;
204 * udev_monitor_get_fd:
205 * @udev_monitor: udev monitor
207 * Retrieve the socket file descriptor associated with the monitor.
209 * Returns: the socket file descriptor
211 int udev_monitor_get_fd(struct udev_monitor *udev_monitor)
213 if (udev_monitor == NULL)
215 return udev_monitor->sock;
219 * udev_monitor_receive_device:
220 * @udev_monitor: udev monitor
222 * Receive data from the udev monitor socket, allocate a new udev
223 * device, fill in the received data, and return the device.
225 * Only socket connections with uid=0 are accepted. The caller
226 * needs to make sure, that there is data to read from the socket,
227 * the call will block until the socket becomes readable.
229 * The initial refcount is 1, and needs to be decremented to
230 * release the ressources of the udev device.
232 * Returns: a new udev device, or #NULL, in case of an error
234 struct udev_device *udev_monitor_receive_device(struct udev_monitor *udev_monitor)
236 struct udev_device *udev_device;
239 char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
245 if (udev_monitor == NULL)
247 memset(buf, 0x00, sizeof(buf));
249 iov.iov_len = sizeof(buf);
250 memset (&smsg, 0x00, sizeof(struct msghdr));
253 smsg.msg_control = cred_msg;
254 smsg.msg_controllen = sizeof(cred_msg);
256 if (recvmsg(udev_monitor->sock, &smsg, 0) < 0) {
258 info(udev_monitor->udev, "unable to receive message");
262 if (udev_monitor->sun.sun_family != 0) {
263 struct cmsghdr *cmsg = CMSG_FIRSTHDR(&smsg);
264 struct ucred *cred = (struct ucred *)CMSG_DATA (cmsg);
266 if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
267 info(udev_monitor->udev, "no sender credentials received, message ignored");
271 if (cred->uid != 0) {
272 info(udev_monitor->udev, "sender uid=%d, message ignored", cred->uid);
278 bufpos = strlen(buf) + 1;
279 if (bufpos < sizeof("a@/d") || bufpos >= sizeof(buf)) {
280 info(udev_monitor->udev, "invalid message length");
284 /* check message header */
285 if (strstr(buf, "@/") == NULL) {
286 info(udev_monitor->udev, "unrecognized message header");
290 udev_device = device_init(udev_monitor->udev);
291 if (udev_device == NULL) {
295 while (bufpos < sizeof(buf)) {
300 keylen = strlen(key);
303 bufpos += keylen + 1;
305 if (strncmp(key, "DEVPATH=", 8) == 0) {
306 device_set_devpath(udev_device, &key[8]);
307 } else if (strncmp(key, "SUBSYSTEM=", 10) == 0) {
308 device_set_subsystem(udev_device, &key[10]);
309 } else if (strncmp(key, "DEVNAME=", 8) == 0) {
310 device_set_devname(udev_device, &key[8]);
311 } else if (strncmp(key, "DEVLINKS=", 9) == 0) {
312 char *slink = &key[9];
313 char *next = strchr(slink, ' ');
315 while (next != NULL) {
317 device_add_devlink(udev_device, slink);
319 next = strchr(slink, ' ');
321 if (slink[0] != '\0')
322 device_add_devlink(udev_device, slink);
323 } else if (strncmp(key, "DRIVER=", 7) == 0) {
324 device_set_driver(udev_device, &key[7]);
325 } else if (strncmp(key, "ACTION=", 7) == 0) {
326 device_set_action(udev_device, &key[7]);
327 } else if (strncmp(key, "MAJOR=", 6) == 0) {
328 maj = strtoull(&key[6], NULL, 10);
329 } else if (strncmp(key, "MINOR=", 6) == 0) {
330 min = strtoull(&key[6], NULL, 10);
331 } else if (strncmp(key, "DEVPATH_OLD=", 12) == 0) {
332 device_set_devpath_old(udev_device, &key[12]);
333 } else if (strncmp(key, "PHYSDEVPATH=", 12) == 0) {
334 device_set_physdevpath(udev_device, &key[12]);
335 } else if (strncmp(key, "SEQNUM=", 7) == 0) {
336 device_set_seqnum(udev_device, strtoull(&key[7], NULL, 10));
337 } else if (strncmp(key, "TIMEOUT=", 8) == 0) {
338 device_set_timeout(udev_device, strtoull(&key[8], NULL, 10));
340 device_add_property(udev_device, key);
342 device_set_devnum(udev_device, makedev(maj, min));