2 * libudev - interface to udev device information
4 * Copyright (C) 2008 Kay Sievers <kay.sievers@vrfy.org>
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
20 #include <sys/socket.h>
22 #include <linux/netlink.h>
25 #include "libudev-private.h"
31 struct sockaddr_nl snl;
32 struct sockaddr_nl snl_peer;
33 struct sockaddr_un sun;
37 enum udev_monitor_netlink_group {
38 UDEV_MONITOR_KERNEL = 1,
39 UDEV_MONITOR_UDEV = 2,
43 * udev_monitor_new_from_socket:
44 * @udev: udev library context
45 * @socket_path: unix socket path
47 * Create new udev monitor, setup and connect to a specified socket. The
48 * path to a socket can point to an existing socket file, or it will be
49 * created if needed. If neccessary, the permissions adjustment as well as
50 * the later cleanup of the socket file, needs to be done by the caller.
51 * If the socket path starts with a '@' character, an abstract namespace
52 * socket will be used.
54 * The initial refcount is 1, and needs to be decremented to
55 * release the resources of the udev monitor.
57 * Returns: a new udev monitor, or #NULL, in case of an error
59 struct udev_monitor *udev_monitor_new_from_socket(struct udev *udev, const char *socket_path)
61 struct udev_monitor *udev_monitor;
66 if (socket_path == NULL)
68 udev_monitor = calloc(1, sizeof(struct udev_monitor));
69 if (udev_monitor == NULL)
71 udev_monitor->refcount = 1;
72 udev_monitor->udev = udev;
74 udev_monitor->sun.sun_family = AF_LOCAL;
75 if (socket_path[0] == '@') {
76 /* translate leading '@' to abstract namespace */
77 util_strlcpy(udev_monitor->sun.sun_path, socket_path, sizeof(udev_monitor->sun.sun_path));
78 udev_monitor->sun.sun_path[0] = '\0';
79 udev_monitor->addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(socket_path);
80 } else if (stat(socket_path, &statbuf) == 0 && S_ISSOCK(statbuf.st_mode)) {
81 /* existing socket file */
82 util_strlcpy(udev_monitor->sun.sun_path, socket_path, sizeof(udev_monitor->sun.sun_path));
83 udev_monitor->addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(socket_path);
85 /* no socket file, assume abstract namespace socket */
86 util_strlcpy(&udev_monitor->sun.sun_path[1], socket_path, sizeof(udev_monitor->sun.sun_path)-1);
87 udev_monitor->addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(socket_path)+1;
89 udev_monitor->sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
90 if (udev_monitor->sock == -1) {
91 err(udev, "error getting socket: %m\n");
95 util_set_fd_cloexec(udev_monitor->sock);
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, const char *name)
103 struct udev_monitor *udev_monitor;
111 if (strcmp(name, "kernel") == 0)
112 group = UDEV_MONITOR_KERNEL;
113 else if (strcmp(name, "udev") == 0)
114 group = UDEV_MONITOR_UDEV;
118 udev_monitor = calloc(1, sizeof(struct udev_monitor));
119 if (udev_monitor == NULL)
121 udev_monitor->refcount = 1;
122 udev_monitor->udev = udev;
124 udev_monitor->sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
125 if (udev_monitor->sock == -1) {
126 err(udev, "error getting socket: %m\n");
130 util_set_fd_cloexec(udev_monitor->sock);
132 udev_monitor->snl.nl_family = AF_NETLINK;
133 udev_monitor->snl.nl_groups = group;
134 udev_monitor->snl_peer.nl_family = AF_NETLINK;
135 udev_monitor->snl_peer.nl_groups = UDEV_MONITOR_UDEV;
137 dbg(udev, "monitor %p created with NETLINK_KOBJECT_UEVENT (%u)\n", udev_monitor, group);
141 int udev_monitor_enable_receiving(struct udev_monitor *udev_monitor)
146 if (udev_monitor->snl.nl_family != 0) {
147 err = bind(udev_monitor->sock,
148 (struct sockaddr *)&udev_monitor->snl, sizeof(struct sockaddr_nl));
150 err(udev_monitor->udev, "bind failed: %m\n");
153 dbg(udev_monitor->udev, "monitor %p listening on netlink\n", udev_monitor);
154 } else if (udev_monitor->sun.sun_family != 0) {
155 err = bind(udev_monitor->sock,
156 (struct sockaddr *)&udev_monitor->sun, udev_monitor->addrlen);
158 err(udev_monitor->udev, "bind failed: %m\n");
161 /* enable receiving of the sender credentials */
162 setsockopt(udev_monitor->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
163 dbg(udev_monitor->udev, "monitor %p listening on socket\n", udev_monitor);
168 int udev_monitor_set_receive_buffer_size(struct udev_monitor *udev_monitor, int size)
170 if (udev_monitor == NULL)
172 return setsockopt(udev_monitor->sock, SOL_SOCKET, SO_RCVBUFFORCE, &size, sizeof(size));
177 * @udev_monitor: udev monitor
179 * Take a reference of a udev monitor.
181 * Returns: the passed udev monitor
183 struct udev_monitor *udev_monitor_ref(struct udev_monitor *udev_monitor)
185 if (udev_monitor == NULL)
187 udev_monitor->refcount++;
192 * udev_monitor_unref:
193 * @udev_monitor: udev monitor
195 * Drop a reference ofa udev monitor. If the refcount reaches zero,
196 * the bound socket will be closed, and the resources of the monitor
200 void udev_monitor_unref(struct udev_monitor *udev_monitor)
202 if (udev_monitor == NULL)
204 udev_monitor->refcount--;
205 if (udev_monitor->refcount > 0)
207 if (udev_monitor->sock >= 0)
208 close(udev_monitor->sock);
209 dbg(udev_monitor->udev, "monitor %p released\n", udev_monitor);
214 * udev_monitor_get_udev:
215 * @udev_monitor: udev monitor
217 * Retrieve the udev library context the monitor was created with.
219 * Returns: the udev library context
221 struct udev *udev_monitor_get_udev(struct udev_monitor *udev_monitor)
223 if (udev_monitor == NULL)
225 return udev_monitor->udev;
229 * udev_monitor_get_fd:
230 * @udev_monitor: udev monitor
232 * Retrieve the socket file descriptor associated with the monitor.
234 * Returns: the socket file descriptor
236 int udev_monitor_get_fd(struct udev_monitor *udev_monitor)
238 if (udev_monitor == NULL)
240 return udev_monitor->sock;
244 * udev_monitor_receive_device:
245 * @udev_monitor: udev monitor
247 * Receive data from the udev monitor socket, allocate a new udev
248 * device, fill in the received data, and return the device.
250 * Only socket connections with uid=0 are accepted. The caller
251 * needs to make sure that there is data to read from the socket.
252 * The call will block until the socket becomes readable.
254 * The initial refcount is 1, and needs to be decremented to
255 * release the resources of the udev device.
257 * Returns: a new udev device, or #NULL, in case of an error
259 struct udev_device *udev_monitor_receive_device(struct udev_monitor *udev_monitor)
261 struct udev_device *udev_device;
264 char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
268 int subsystem_set = 0;
273 if (udev_monitor == NULL)
275 memset(buf, 0x00, sizeof(buf));
277 iov.iov_len = sizeof(buf);
278 memset (&smsg, 0x00, sizeof(struct msghdr));
281 smsg.msg_control = cred_msg;
282 smsg.msg_controllen = sizeof(cred_msg);
284 if (recvmsg(udev_monitor->sock, &smsg, 0) < 0) {
286 info(udev_monitor->udev, "unable to receive message");
290 if (udev_monitor->sun.sun_family != 0) {
291 struct cmsghdr *cmsg = CMSG_FIRSTHDR(&smsg);
292 struct ucred *cred = (struct ucred *)CMSG_DATA (cmsg);
294 if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
295 info(udev_monitor->udev, "no sender credentials received, message ignored");
299 if (cred->uid != 0) {
300 info(udev_monitor->udev, "sender uid=%d, message ignored", cred->uid);
306 bufpos = strlen(buf) + 1;
307 if (bufpos < sizeof("a@/d") || bufpos >= sizeof(buf)) {
308 info(udev_monitor->udev, "invalid message length");
312 /* check message header */
313 if (strstr(buf, "@/") == NULL) {
314 info(udev_monitor->udev, "unrecognized message header");
318 udev_device = device_new(udev_monitor->udev);
319 if (udev_device == NULL) {
323 while (bufpos < sizeof(buf)) {
328 keylen = strlen(key);
331 bufpos += keylen + 1;
333 if (strncmp(key, "DEVPATH=", 8) == 0) {
334 char path[UTIL_PATH_SIZE];
336 util_strlcpy(path, udev_get_sys_path(udev_monitor->udev), sizeof(path));
337 util_strlcat(path, &key[8], sizeof(path));
338 udev_device_set_syspath(udev_device, path);
340 } else if (strncmp(key, "SUBSYSTEM=", 10) == 0) {
341 udev_device_set_subsystem(udev_device, &key[10]);
343 } else if (strncmp(key, "DEVTYPE=", 8) == 0) {
344 udev_device_set_devtype(udev_device, &key[8]);
345 } else if (strncmp(key, "DEVNAME=", 8) == 0) {
346 udev_device_set_devnode(udev_device, &key[8]);
347 } else if (strncmp(key, "DEVLINKS=", 9) == 0) {
348 char devlinks[UTIL_PATH_SIZE];
352 util_strlcpy(devlinks, &key[9], sizeof(devlinks));
354 next = strchr(slink, ' ');
355 while (next != NULL) {
357 udev_device_add_devlink(udev_device, slink);
359 next = strchr(slink, ' ');
361 if (slink[0] != '\0')
362 udev_device_add_devlink(udev_device, slink);
363 } else if (strncmp(key, "DRIVER=", 7) == 0) {
364 udev_device_set_driver(udev_device, &key[7]);
365 } else if (strncmp(key, "ACTION=", 7) == 0) {
366 udev_device_set_action(udev_device, &key[7]);
368 } else if (strncmp(key, "MAJOR=", 6) == 0) {
369 maj = strtoull(&key[6], NULL, 10);
370 } else if (strncmp(key, "MINOR=", 6) == 0) {
371 min = strtoull(&key[6], NULL, 10);
372 } else if (strncmp(key, "DEVPATH_OLD=", 12) == 0) {
373 udev_device_set_devpath_old(udev_device, &key[12]);
374 } else if (strncmp(key, "PHYSDEVPATH=", 12) == 0) {
375 udev_device_set_physdevpath(udev_device, &key[12]);
376 } else if (strncmp(key, "SEQNUM=", 7) == 0) {
377 udev_device_set_seqnum(udev_device, strtoull(&key[7], NULL, 10));
378 } else if (strncmp(key, "TIMEOUT=", 8) == 0) {
379 udev_device_set_timeout(udev_device, strtoull(&key[8], NULL, 10));
380 } else if (strncmp(key, "PHYSDEV", 7) == 0) {
381 /* skip deprecated values */
384 udev_device_add_property_from_string(udev_device, key);
387 if (!devpath_set || !subsystem_set || !action_set) {
388 info(udev_monitor->udev, "missing values, skip\n");
389 udev_device_unref(udev_device);
393 udev_device_set_devnum(udev_device, makedev(maj, min));
394 udev_device_set_info_loaded(udev_device);
398 int udev_monitor_send_device(struct udev_monitor *udev_monitor, struct udev_device *udev_device)
404 len = udev_device_get_properties_monitor_buf(udev_device, &buf);
407 if (udev_monitor->sun.sun_family != 0) {
408 count = sendto(udev_monitor->sock,
410 (struct sockaddr *)&udev_monitor->sun,
411 udev_monitor->addrlen);
413 /* no destination besides the muticast group, we will always get -1 ECONNREFUSED */
414 count = sendto(udev_monitor->sock,
416 (struct sockaddr *)&udev_monitor->snl_peer,
417 sizeof(struct sockaddr_nl));
419 info(udev_monitor->udev, "passed %zi bytes to monitor %p, \n", count, udev_monitor);