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>
34 #include "libudev-private.h"
41 struct sockaddr_un saddr;
46 * udev_monitor_new_from_socket:
47 * @udev: udev library context
48 * @socket_path: unix socket path
50 * Create new udev monitor, setup and connect to a specified socket. The
51 * path to a socket can point to an existing socket file, or it will be
52 * created if needed. If neccessary, the permissions adjustment as well as
53 * the later cleanup of the socket file, needs to be done by the caller.
54 * If the socket path starts with a '@' character, an abstract namespace
55 * socket will be used.
57 * The initial refcount is 1, and needs to be decremented to
58 * release the ressources of the udev monitor.
60 * Returns: a new udev monitor, or #NULL, in case of an error
62 struct udev_monitor *udev_monitor_new_from_socket(struct udev *udev, const char *socket_path)
64 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->saddr.sun_family = AF_LOCAL;
78 strcpy(udev_monitor->saddr.sun_path, socket_path);
79 udev_monitor->addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(udev_monitor->saddr.sun_path);
81 /* translate leading '@' to abstract namespace */
82 if (udev_monitor->saddr.sun_path[0] == '@')
83 udev_monitor->saddr.sun_path[0] = '\0';
85 udev_monitor->sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
86 if (udev_monitor->sock == -1) {
87 err(udev, "error getting socket: %s\n", strerror(errno));
91 info(udev, "monitor %p created with '%s'\n", udev_monitor, socket_path);
95 int udev_monitor_enable_receiving(struct udev_monitor *udev_monitor)
100 err = bind(udev_monitor->sock, (struct sockaddr *)&udev_monitor->saddr, udev_monitor->addrlen);
102 err(udev_monitor->udev, "bind failed: %s\n", strerror(errno));
106 /* enable receiving of the sender credentials */
107 setsockopt(udev_monitor->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
108 info(udev_monitor->udev, "monitor %p listening\n", udev_monitor);
114 * @udev_monitor: udev monitor
116 * Take a reference of a udev monitor.
118 * Returns: the passed udev monitor
120 struct udev_monitor *udev_monitor_ref(struct udev_monitor *udev_monitor)
122 if (udev_monitor == NULL)
124 udev_monitor->refcount++;
129 * udev_monitor_unref:
130 * @udev_monitor: udev monitor
132 * Drop a reference ofa udev monitor. If the refcount reaches zero,
133 * the bound socket will be closed, and the ressources of the monitor
137 void udev_monitor_unref(struct udev_monitor *udev_monitor)
139 if (udev_monitor == NULL)
141 udev_monitor->refcount--;
142 if (udev_monitor->refcount > 0)
144 if (udev_monitor->sock >= 0)
145 close(udev_monitor->sock);
146 info(udev_monitor->udev, "monitor %p released\n", udev_monitor);
151 * udev_monitor_get_udev:
152 * @udev_monitor: udev monitor
154 * Retrieve the udev library context the monitor was created with.
156 * Returns: the udev library context
158 struct udev *udev_monitor_get_udev(struct udev_monitor *udev_monitor)
160 if (udev_monitor == NULL)
162 return udev_monitor->udev;
166 * udev_monitor_get_fd:
167 * @udev_monitor: udev monitor
169 * Retrieve the socket file descriptor associated with the monitor.
171 * Returns: the socket file descriptor
173 int udev_monitor_get_fd(struct udev_monitor *udev_monitor)
175 if (udev_monitor == NULL)
177 return udev_monitor->sock;
181 * udev_monitor_receive_device:
182 * @udev_monitor: udev monitor
184 * Receive data from the udev monitor socket, allocate a new udev
185 * device, fill in the received data, and return the device.
187 * Only socket connections with uid=0 are accepted. The caller
188 * needs to make sure, that there is data to read from the socket,
189 * the call will block until the socket becomes readable.
191 * The initial refcount is 1, and needs to be decremented to
192 * release the ressources of the udev device.
194 * Returns: a new udev device, or #NULL, in case of an error
196 struct udev_device *udev_monitor_receive_device(struct udev_monitor *udev_monitor)
198 struct udev_device *udev_device;
200 struct cmsghdr *cmsg;
203 char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
209 if (udev_monitor == NULL)
211 memset(buf, 0x00, sizeof(buf));
213 iov.iov_len = sizeof(buf);
214 memset (&smsg, 0x00, sizeof(struct msghdr));
217 smsg.msg_control = cred_msg;
218 smsg.msg_controllen = sizeof(cred_msg);
220 if (recvmsg(udev_monitor->sock, &smsg, 0) < 0) {
222 info(udev_monitor->udev, "unable to receive message");
225 cmsg = CMSG_FIRSTHDR(&smsg);
226 cred = (struct ucred *)CMSG_DATA (cmsg);
228 if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
229 info(udev_monitor->udev, "no sender credentials received, message ignored");
233 if (cred->uid != 0) {
234 info(udev_monitor->udev, "sender uid=%d, message ignored", cred->uid);
239 bufpos = strlen(buf) + 1;
240 if (bufpos < sizeof("a@/d") || bufpos >= sizeof(buf)) {
241 info(udev_monitor->udev, "invalid message length");
245 /* check message header */
246 if (strstr(buf, "@/") == NULL) {
247 info(udev_monitor->udev, "unrecognized message header");
251 udev_device = device_init(udev_monitor->udev);
252 if (udev_device == NULL) {
256 while (bufpos < sizeof(buf)) {
261 keylen = strlen(key);
264 bufpos += keylen + 1;
266 if (strncmp(key, "DEVPATH=", 8) == 0) {
267 device_set_devpath(udev_device, &key[8]);
268 } else if (strncmp(key, "SUBSYSTEM=", 10) == 0) {
269 device_set_subsystem(udev_device, &key[10]);
270 } else if (strncmp(key, "DEVNAME=", 8) == 0) {
271 device_set_devname(udev_device, &key[8]);
272 } else if (strncmp(key, "DEVLINKS=", 9) == 0) {
273 char *slink = &key[9];
274 char *next = strchr(slink, ' ');
276 while (next != NULL) {
278 device_add_devlink(udev_device, slink);
280 next = strchr(slink, ' ');
282 if (slink[0] != '\0')
283 device_add_devlink(udev_device, slink);
284 } else if (strncmp(key, "DRIVER=", 7) == 0) {
285 device_set_driver(udev_device, &key[7]);
286 } else if (strncmp(key, "ACTION=", 7) == 0) {
287 device_set_action(udev_device, &key[7]);
288 } else if (strncmp(key, "MAJOR=", 6) == 0) {
289 maj = strtoull(&key[6], NULL, 10);
290 } else if (strncmp(key, "MINOR=", 6) == 0) {
291 min = strtoull(&key[6], NULL, 10);
292 } else if (strncmp(key, "DEVPATH_OLD=", 12) == 0) {
293 device_set_devpath_old(udev_device, &key[12]);
294 } else if (strncmp(key, "PHYSDEVPATH=", 12) == 0) {
295 device_set_physdevpath(udev_device, &key[12]);
296 } else if (strncmp(key, "SEQNUM=", 7) == 0) {
297 device_set_seqnum(udev_device, strtoull(&key[7], NULL, 10));
298 } else if (strncmp(key, "TIMEOUT=", 8) == 0) {
299 device_set_timeout(udev_device, strtoull(&key[8], NULL, 10));
301 device_add_property(udev_device, key);
303 device_set_devnum(udev_device, makedev(maj, min));