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));
94 int udev_monitor_enable_receiving(struct udev_monitor *udev_monitor)
99 err = bind(udev_monitor->sock, (struct sockaddr *) &udev_monitor->saddr, udev_monitor->addrlen);
101 err(udev_monitor->udev, "bind failed: %s\n", strerror(errno));
105 /* enable receiving of the sender credentials */
106 setsockopt(udev_monitor->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
107 info(udev_monitor->udev, "udev_monitor: %p created\n", udev_monitor);
113 * @udev_monitor: udev monitor
115 * Take a reference of a udev monitor.
117 * Returns: the passed udev monitor
119 struct udev_monitor *udev_monitor_ref(struct udev_monitor *udev_monitor)
121 if (udev_monitor == NULL)
123 udev_monitor->refcount++;
128 * udev_monitor_unref:
129 * @udev_monitor: udev monitor
131 * Drop a reference ofa udev monitor. If the refcount reaches zero,
132 * the bound socket will be closed, and the ressources of the monitor
136 void udev_monitor_unref(struct udev_monitor *udev_monitor)
138 if (udev_monitor == NULL)
140 udev_monitor->refcount--;
141 if (udev_monitor->refcount > 0)
143 if (udev_monitor->sock >= 0)
144 close(udev_monitor->sock);
145 info(udev_monitor->udev, "udev_monitor: %p released\n", udev_monitor);
150 * udev_monitor_get_udev:
151 * @udev_monitor: udev monitor
153 * Retrieve the udev library context the monitor was created with.
155 * Returns: the udev library context
157 struct udev *udev_monitor_get_udev(struct udev_monitor *udev_monitor)
159 if (udev_monitor == NULL)
161 return udev_monitor->udev;
165 * udev_monitor_get_fd:
166 * @udev_monitor: udev monitor
168 * Retrieve the socket file descriptor associated with the monitor.
170 * Returns: the socket file descriptor
172 int udev_monitor_get_fd(struct udev_monitor *udev_monitor)
174 if (udev_monitor == NULL)
176 return udev_monitor->sock;
180 * udev_monitor_receive_device:
181 * @udev_monitor: udev monitor
183 * Receive data from the udev monitor socket, allocate a new udev
184 * device, fill in the received data, and return the device.
186 * Only socket connections with uid=0 are accepted. The caller
187 * needs to make sure, that there is data to read from the socket,
188 * the call will block until the socket becomes readable.
190 * The initial refcount is 1, and needs to be decremented to
191 * release the ressources of the udev device.
193 * Returns: a new udev device, or #NULL, in case of an error
195 struct udev_device *udev_monitor_receive_device(struct udev_monitor *udev_monitor)
197 struct udev_device *udev_device;
199 struct cmsghdr *cmsg;
202 char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
206 if (udev_monitor == NULL)
208 memset(buf, 0x00, sizeof(buf));
210 iov.iov_len = sizeof(buf);
211 memset (&smsg, 0x00, sizeof(struct msghdr));
214 smsg.msg_control = cred_msg;
215 smsg.msg_controllen = sizeof(cred_msg);
217 if (recvmsg(udev_monitor->sock, &smsg, 0) < 0) {
219 info(udev_monitor->udev, "unable to receive message");
222 cmsg = CMSG_FIRSTHDR(&smsg);
223 cred = (struct ucred *)CMSG_DATA (cmsg);
225 if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
226 info(udev_monitor->udev, "no sender credentials received, message ignored");
230 if (cred->uid != 0) {
231 info(udev_monitor->udev, "sender uid=%d, message ignored", cred->uid);
236 bufpos = strlen(buf) + 1;
237 if (bufpos < sizeof("a@/d") || bufpos >= sizeof(buf)) {
238 info(udev_monitor->udev, "invalid message length");
242 /* check message header */
243 if (strstr(buf, "@/") == NULL) {
244 info(udev_monitor->udev, "unrecognized message header");
248 udev_device = device_init(udev_monitor->udev);
249 if (udev_device == NULL) {
253 while (bufpos < sizeof(buf)) {
258 keylen = strlen(key);
261 bufpos += keylen + 1;
263 if (strncmp(key, "DEVPATH=", 8) == 0) {
264 device_set_devpath(udev_device, &key[8]);
265 } else if (strncmp(key, "SUBSYSTEM=", 10) == 0) {
266 device_set_subsystem(udev_device, &key[10]);
267 } else if (strncmp(key, "DEVNAME=", 8) == 0) {
268 device_set_devname(udev_device, &key[8]);
269 } else if (strncmp(key, "DEVLINKS=", 9) == 0) {
270 char *slink = &key[9];
271 char *next = strchr(slink, ' ');
273 while (next != NULL) {
275 device_add_devlink(udev_device, slink);
277 next = strchr(slink, ' ');
279 if (slink[0] != '\0')
280 device_add_devlink(udev_device, slink);
282 device_add_property(udev_device, key);