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;
67 if (socket_path == NULL)
69 udev_monitor = malloc(sizeof(struct udev_monitor));
70 if (udev_monitor == NULL)
72 memset(udev_monitor, 0x00, sizeof(struct udev_monitor));
73 udev_monitor->refcount = 1;
74 udev_monitor->udev = udev;
76 udev_monitor->sun.sun_family = AF_LOCAL;
77 strcpy(udev_monitor->sun.sun_path, socket_path);
78 udev_monitor->addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(udev_monitor->sun.sun_path);
80 /* translate leading '@' to abstract namespace */
81 if (udev_monitor->sun.sun_path[0] == '@')
82 udev_monitor->sun.sun_path[0] = '\0';
84 udev_monitor->sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
85 if (udev_monitor->sock == -1) {
86 err(udev, "error getting socket: %m\n");
90 info(udev, "monitor %p created with '%s'\n", udev_monitor, socket_path);
94 struct udev_monitor *udev_monitor_new_from_netlink(struct udev *udev)
96 struct udev_monitor *udev_monitor;
100 udev_monitor = malloc(sizeof(struct udev_monitor));
101 if (udev_monitor == NULL)
103 memset(udev_monitor, 0x00, sizeof(struct udev_monitor));
104 udev_monitor->refcount = 1;
105 udev_monitor->udev = udev;
107 udev_monitor->sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
108 if (udev_monitor->sock == -1) {
109 err(udev, "error getting socket: %m\n");
114 udev_monitor->snl.nl_family = AF_NETLINK;
115 udev_monitor->snl.nl_pid = getpid();
116 udev_monitor->snl.nl_groups = 1;
118 info(udev, "monitor %p created with NETLINK_KOBJECT_UEVENT\n", udev_monitor);
122 int udev_monitor_enable_receiving(struct udev_monitor *udev_monitor)
127 if (udev_monitor->snl.nl_family != 0) {
128 err = bind(udev_monitor->sock, (struct sockaddr *)&udev_monitor->snl, sizeof(struct sockaddr_nl));
130 err(udev_monitor->udev, "bind failed: %m\n");
133 info(udev_monitor->udev, "monitor %p listening on netlink\n", udev_monitor);
134 } else if (udev_monitor->sun.sun_family != 0) {
135 err = bind(udev_monitor->sock, (struct sockaddr *)&udev_monitor->sun, udev_monitor->addrlen);
137 err(udev_monitor->udev, "bind failed: %m\n");
140 /* enable receiving of the sender credentials */
141 setsockopt(udev_monitor->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
142 info(udev_monitor->udev, "monitor %p listening on socket\n", udev_monitor);
149 * @udev_monitor: udev monitor
151 * Take a reference of a udev monitor.
153 * Returns: the passed udev monitor
155 struct udev_monitor *udev_monitor_ref(struct udev_monitor *udev_monitor)
157 if (udev_monitor == NULL)
159 udev_monitor->refcount++;
164 * udev_monitor_unref:
165 * @udev_monitor: udev monitor
167 * Drop a reference ofa udev monitor. If the refcount reaches zero,
168 * the bound socket will be closed, and the ressources of the monitor
172 void udev_monitor_unref(struct udev_monitor *udev_monitor)
174 if (udev_monitor == NULL)
176 udev_monitor->refcount--;
177 if (udev_monitor->refcount > 0)
179 if (udev_monitor->sock >= 0)
180 close(udev_monitor->sock);
181 info(udev_monitor->udev, "monitor %p released\n", udev_monitor);
186 * udev_monitor_get_udev:
187 * @udev_monitor: udev monitor
189 * Retrieve the udev library context the monitor was created with.
191 * Returns: the udev library context
193 struct udev *udev_monitor_get_udev(struct udev_monitor *udev_monitor)
195 if (udev_monitor == NULL)
197 return udev_monitor->udev;
201 * udev_monitor_get_fd:
202 * @udev_monitor: udev monitor
204 * Retrieve the socket file descriptor associated with the monitor.
206 * Returns: the socket file descriptor
208 int udev_monitor_get_fd(struct udev_monitor *udev_monitor)
210 if (udev_monitor == NULL)
212 return udev_monitor->sock;
216 * udev_monitor_receive_device:
217 * @udev_monitor: udev monitor
219 * Receive data from the udev monitor socket, allocate a new udev
220 * device, fill in the received data, and return the device.
222 * Only socket connections with uid=0 are accepted. The caller
223 * needs to make sure, that there is data to read from the socket,
224 * the call will block until the socket becomes readable.
226 * The initial refcount is 1, and needs to be decremented to
227 * release the ressources of the udev device.
229 * Returns: a new udev device, or #NULL, in case of an error
231 struct udev_device *udev_monitor_receive_device(struct udev_monitor *udev_monitor)
233 struct udev_device *udev_device;
236 char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
242 if (udev_monitor == NULL)
244 memset(buf, 0x00, sizeof(buf));
246 iov.iov_len = sizeof(buf);
247 memset (&smsg, 0x00, sizeof(struct msghdr));
250 smsg.msg_control = cred_msg;
251 smsg.msg_controllen = sizeof(cred_msg);
253 if (recvmsg(udev_monitor->sock, &smsg, 0) < 0) {
255 info(udev_monitor->udev, "unable to receive message");
259 if (udev_monitor->sun.sun_family != 0) {
260 struct cmsghdr *cmsg = CMSG_FIRSTHDR(&smsg);
261 struct ucred *cred = (struct ucred *)CMSG_DATA (cmsg);
263 if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
264 info(udev_monitor->udev, "no sender credentials received, message ignored");
268 if (cred->uid != 0) {
269 info(udev_monitor->udev, "sender uid=%d, message ignored", cred->uid);
275 bufpos = strlen(buf) + 1;
276 if (bufpos < sizeof("a@/d") || bufpos >= sizeof(buf)) {
277 info(udev_monitor->udev, "invalid message length");
281 /* check message header */
282 if (strstr(buf, "@/") == NULL) {
283 info(udev_monitor->udev, "unrecognized message header");
287 udev_device = device_new(udev_monitor->udev);
288 if (udev_device == NULL) {
292 while (bufpos < sizeof(buf)) {
297 keylen = strlen(key);
300 bufpos += keylen + 1;
302 if (strncmp(key, "DEVPATH=", 8) == 0) {
303 char path[UTIL_PATH_SIZE];
305 util_strlcpy(path, udev_get_sys_path(udev_monitor->udev), sizeof(path));
306 util_strlcat(path, &key[8], sizeof(path));
307 device_set_syspath(udev_device, path);
308 } else if (strncmp(key, "SUBSYSTEM=", 10) == 0) {
309 device_set_subsystem(udev_device, &key[10]);
310 } else if (strncmp(key, "DEVNAME=", 8) == 0) {
311 device_set_devnode(udev_device, &key[8]);
312 } else if (strncmp(key, "DEVLINKS=", 9) == 0) {
313 char *slink = &key[9];
314 char *next = strchr(slink, ' ');
316 while (next != NULL) {
318 device_add_devlink(udev_device, slink);
320 next = strchr(slink, ' ');
322 if (slink[0] != '\0')
323 device_add_devlink(udev_device, slink);
324 } else if (strncmp(key, "DRIVER=", 7) == 0) {
325 device_set_driver(udev_device, &key[7]);
326 } else if (strncmp(key, "ACTION=", 7) == 0) {
327 device_set_action(udev_device, &key[7]);
328 } else if (strncmp(key, "MAJOR=", 6) == 0) {
329 maj = strtoull(&key[6], NULL, 10);
330 } else if (strncmp(key, "MINOR=", 6) == 0) {
331 min = strtoull(&key[6], NULL, 10);
332 } else if (strncmp(key, "DEVPATH_OLD=", 12) == 0) {
333 device_set_devpath_old(udev_device, &key[12]);
334 } else if (strncmp(key, "PHYSDEVPATH=", 12) == 0) {
335 device_set_physdevpath(udev_device, &key[12]);
336 } else if (strncmp(key, "SEQNUM=", 7) == 0) {
337 device_set_seqnum(udev_device, strtoull(&key[7], NULL, 10));
338 } else if (strncmp(key, "TIMEOUT=", 8) == 0) {
339 device_set_timeout(udev_device, strtoull(&key[8], NULL, 10));
341 if (strncmp(key, "PHYSDEV", 7) == 0)
343 device_add_property_from_string(udev_device, key);
345 device_set_devnum(udev_device, makedev(maj, min));
347 device_set_info_loaded(udev_device);