[thirdparty/systemd.git] / udev / lib / libudev-monitor.c

/*
 * libudev - interface to udev device information
 *
 * Copyright (C) 2008 Kay Sievers <kay.sievers@vrfy.org>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "config.h"

#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <dirent.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/un.h>

#include "libudev.h"
#include "libudev-private.h"
#include "../udev.h"

struct udev_monitor {
	struct udev *udev;
	int refcount;
	int socket;
};

struct udev_monitor *udev_monitor_new_from_socket(struct udev *udev, const char *socket_path)
{
	struct udev_monitor *udev_monitor;
	struct sockaddr_un saddr;
	socklen_t addrlen;
	const int on = 1;

	if (udev == NULL)
		return NULL;
	if (socket_path == NULL)
		return NULL;
	udev_monitor = malloc(sizeof(struct udev_monitor));
	if (udev_monitor == NULL)
		return NULL;
	memset(udev_monitor, 0x00, sizeof(struct udev_monitor));
	udev_monitor->refcount = 1;
	udev_monitor->udev = udev;

	memset(&saddr, 0x00, sizeof(saddr));
	saddr.sun_family = AF_LOCAL;
	strcpy(saddr.sun_path, socket_path);
	addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path);

	/* translate leading '@' to abstract namespace */
	if (saddr.sun_path[0] == '@')
		saddr.sun_path[0] = '\0';

	udev_monitor->socket = socket(AF_LOCAL, SOCK_DGRAM, 0);
	if (udev_monitor->socket == -1) {
		log_err(udev, "error getting socket: %s\n", strerror(errno));
		free(udev_monitor);
		return NULL;
	}

	if (bind(udev_monitor->socket, (struct sockaddr *) &saddr, addrlen) < 0) {
		log_err(udev, "bind failed: %s\n", strerror(errno));
		close(udev_monitor->socket);
		free(udev_monitor);
		return NULL;
	}

	/* enable receiving of the sender credentials */
	setsockopt(udev_monitor->socket, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
	log_info(udev_monitor->udev, "udev_monitor: %p created\n", udev_monitor);

	return udev_monitor;
}

struct udev_monitor *udev_monitor_ref(struct udev_monitor *udev_monitor)
{
	if (udev_monitor == NULL)
		return NULL;
	udev_monitor->refcount++;
	return udev_monitor;
}

void udev_monitor_unref(struct udev_monitor *udev_monitor)
{
	if (udev_monitor == NULL)
		return;
	udev_monitor->refcount--;
	if (udev_monitor->refcount > 0)
		return;
	close(udev_monitor->socket);
	log_info(udev_monitor->udev, "udev_monitor: %p released\n", udev_monitor);
	free(udev_monitor);
}

struct udev *udev_monitor_get_udev(struct udev_monitor *udev_monitor)
{
	if (udev_monitor == NULL)
		return NULL;
	return udev_monitor->udev;
}

int udev_monitor_get_fd(struct udev_monitor *udev_monitor)
{
	if (udev_monitor == NULL)
		return -1;
	return udev_monitor->socket;
}

struct udev_device *udev_monitor_get_device(struct udev_monitor *udev_monitor)
{
	struct udev_device *udev_device;
	struct msghdr smsg;
	struct cmsghdr *cmsg;
	struct iovec iov;
	struct ucred *cred;
	char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
	char buf[4096];
	size_t bufpos;

	if (udev_monitor == NULL)
		return NULL;
	memset(buf, 0x00, sizeof(buf));
	iov.iov_base = &buf;
	iov.iov_len = sizeof(buf);
	memset (&smsg, 0x00, sizeof(struct msghdr));
	smsg.msg_iov = &iov;
	smsg.msg_iovlen = 1;
	smsg.msg_control = cred_msg;
	smsg.msg_controllen = sizeof(cred_msg);

	if (recvmsg(udev_monitor->socket, &smsg, 0) < 0) {
		if (errno != EINTR)
			log_info(udev_monitor->udev, "unable to receive message");
		return NULL;
	}
	cmsg = CMSG_FIRSTHDR(&smsg);
	cred = (struct ucred *)CMSG_DATA (cmsg);

	if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
		log_info(udev_monitor->udev, "no sender credentials received, message ignored");
		return NULL;
	}

	if (cred->uid != 0) {
		log_info(udev_monitor->udev, "sender uid=%d, message ignored", cred->uid);
		return NULL;
	}

	/* skip header */
	bufpos = strlen(buf) + 1;
	if (bufpos < sizeof("a@/d") || bufpos >= sizeof(buf)) {
		log_info(udev_monitor->udev, "invalid message length");
		return NULL;
	}

	/* check message header */
	if (strstr(buf, "@/") == NULL) {
		log_info(udev_monitor->udev, "unrecognized message header");
		return NULL;
	}

	udev_device = device_init(udev_monitor->udev);
	if (udev_device == NULL) {
		return NULL;
	}

	while (bufpos < sizeof(buf)) {
		char *key;
		size_t keylen;

		key = &buf[bufpos];
		keylen = strlen(key);
		if (keylen == 0)
			break;
		bufpos += keylen + 1;

		if (strncmp(key, "DEVPATH=", 8) == 0) {
			udev_device->devpath = strdup(&key[8]);
		} else if (strncmp(key, "SUBSYSTEM=", 10) == 0) {
			udev_device->subsystem = strdup(&key[10]);
		} else if (strncmp(key, "DEVNAME=", 8) == 0) {
			udev_device->devname = strdup(&key[8]);
		} else if (strncmp(key, "DEVLINKS=", 9) == 0) {
			char *slink = &key[9];
			char *next = strchr(slink, ' ');

			while (next != NULL) {
				next[0] = '\0';
				name_list_add(&udev_device->link_list, slink, 0);
				slink = &next[1];
				next = strchr(slink, ' ');
			}
			if (slink[0] != '\0')
				name_list_add(&udev_device->link_list, slink, 0);
		}
		name_list_add(&udev_device->env_list, key, 0);
	}

	return udev_device;
}
Commit	Line	Data
ba6929f6 KS	1	/*
	2	* libudev - interface to udev device information
	3	*
	4	* Copyright (C) 2008 Kay Sievers <kay.sievers@vrfy.org>
	5	*
	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.
	10	*
	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.
	15	*
	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/>.
	18	*/
	19
	20	#include "config.h"
	21
	22	#include <stdio.h>
	23	#include <stdlib.h>
	24	#include <stddef.h>
	25	#include <unistd.h>
	26	#include <errno.h>
	27	#include <string.h>
	28	#include <dirent.h>
	29	#include <sys/stat.h>
	30	#include <sys/socket.h>
	31	#include <sys/un.h>
	32
	33	#include "libudev.h"
	34	#include "libudev-private.h"
	35	#include "../udev.h"
	36
	37	struct udev_monitor {
	38	struct udev *udev;
	39	int refcount;
	40	int socket;
	41	};
	42
	43	struct udev_monitor udev_monitor_new_from_socket(struct udev udev, const char *socket_path)
	44	{
	45	struct udev_monitor *udev_monitor;
	46	struct sockaddr_un saddr;
	47	socklen_t addrlen;
	48	const int on = 1;
	49
	50	if (udev == NULL)
	51	return NULL;
	52	if (socket_path == NULL)
	53	return NULL;
	54	udev_monitor = malloc(sizeof(struct udev_monitor));
	55	if (udev_monitor == NULL)
	56	return NULL;
	57	memset(udev_monitor, 0x00, sizeof(struct udev_monitor));
	58	udev_monitor->refcount = 1;
	59	udev_monitor->udev = udev;
	60
	61	memset(&saddr, 0x00, sizeof(saddr));
	62	saddr.sun_family = AF_LOCAL;
	63	strcpy(saddr.sun_path, socket_path);
	64	addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path);
65
66	/* translate leading '@' to abstract namespace */
67	if (saddr.sun_path[0] == '@')
68	saddr.sun_path[0] = '\0';
69
70	udev_monitor->socket = socket(AF_LOCAL, SOCK_DGRAM, 0);
71	if (udev_monitor->socket == -1) {
72	log_err(udev, "error getting socket: %s\n", strerror(errno));
73	free(udev_monitor);
74	return NULL;
75	}
76
77	if (bind(udev_monitor->socket, (struct sockaddr *) &saddr, addrlen) < 0) {
78	log_err(udev, "bind failed: %s\n", strerror(errno));
79	close(udev_monitor->socket);
80	free(udev_monitor);
81	return NULL;
82	}
83
84	/* enable receiving of the sender credentials */
85	setsockopt(udev_monitor->socket, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
86	log_info(udev_monitor->udev, "udev_monitor: %p created\n", udev_monitor);
87
88	return udev_monitor;
89	}
90
91	struct udev_monitor udev_monitor_ref(struct udev_monitor udev_monitor)
92	{
93	if (udev_monitor == NULL)
94	return NULL;
95	udev_monitor->refcount++;
96	return udev_monitor;
97	}
98
99	void udev_monitor_unref(struct udev_monitor *udev_monitor)
100	{
101	if (udev_monitor == NULL)
102	return;
103	udev_monitor->refcount--;
104	if (udev_monitor->refcount > 0)
105	return;
106	close(udev_monitor->socket);
107	log_info(udev_monitor->udev, "udev_monitor: %p released\n", udev_monitor);
108	free(udev_monitor);
109	}
110
111	struct udev udev_monitor_get_udev(struct udev_monitor udev_monitor)
112	{
113	if (udev_monitor == NULL)
114	return NULL;
115	return udev_monitor->udev;
116	}
117
118	int udev_monitor_get_fd(struct udev_monitor *udev_monitor)
119	{
120	if (udev_monitor == NULL)
121	return -1;
122	return udev_monitor->socket;
123	}
124
125	struct udev_device udev_monitor_get_device(struct udev_monitor udev_monitor)
126	{
127	struct udev_device *udev_device;
128	struct msghdr smsg;
129	struct cmsghdr *cmsg;
130	struct iovec iov;
131	struct ucred *cred;
132	char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
133	char buf[4096];
134	size_t bufpos;
135
136	if (udev_monitor == NULL)
137	return NULL;
138	memset(buf, 0x00, sizeof(buf));
139	iov.iov_base = &buf;
140	iov.iov_len = sizeof(buf);
141	memset (&smsg, 0x00, sizeof(struct msghdr));
142	smsg.msg_iov = &iov;
143	smsg.msg_iovlen = 1;
144	smsg.msg_control = cred_msg;
145	smsg.msg_controllen = sizeof(cred_msg);
146
147	if (recvmsg(udev_monitor->socket, &smsg, 0) < 0) {
148	if (errno != EINTR)
149	log_info(udev_monitor->udev, "unable to receive message");
150	return NULL;
151	}
152	cmsg = CMSG_FIRSTHDR(&smsg);
153	cred = (struct ucred *)CMSG_DATA (cmsg);
154
155	if (cmsg == NULL \|\| cmsg->cmsg_type != SCM_CREDENTIALS) {
156	log_info(udev_monitor->udev, "no sender credentials received, message ignored");
157	return NULL;
158	}
159
160	if (cred->uid != 0) {
161	log_info(udev_monitor->udev, "sender uid=%d, message ignored", cred->uid);
162	return NULL;
163	}
164
165	/* skip header */
166	bufpos = strlen(buf) + 1;
167	if (bufpos < sizeof("a@/d") \|\| bufpos >= sizeof(buf)) {
168	log_info(udev_monitor->udev, "invalid message length");
169	return NULL;
170	}
171
172	/* check message header */
173	if (strstr(buf, "@/") == NULL) {
174	log_info(udev_monitor->udev, "unrecognized message header");
175	return NULL;
176	}
177
178	udev_device = device_init(udev_monitor->udev);
179	if (udev_device == NULL) {
180	return NULL;
181	}
182
183	while (bufpos < sizeof(buf)) {
184	char *key;
185	size_t keylen;
186
187	key = &buf[bufpos];
188	keylen = strlen(key);
189	if (keylen == 0)
190	break;
191	bufpos += keylen + 1;
192
193	if (strncmp(key, "DEVPATH=", 8) == 0) {
194	udev_device->devpath = strdup(&key[8]);
195	} else if (strncmp(key, "SUBSYSTEM=", 10) == 0) {
196	udev_device->subsystem = strdup(&key[10]);
197	} else if (strncmp(key, "DEVNAME=", 8) == 0) {
198	udev_device->devname = strdup(&key[8]);
199	} else if (strncmp(key, "DEVLINKS=", 9) == 0) {
200	char *slink = &key[9];
201	char *next = strchr(slink, ' ');
202
203	while (next != NULL) {
204	next[0] = '\0';
205	name_list_add(&udev_device->link_list, slink, 0);
206	slink = &next[1];
207	next = strchr(slink, ' ');
208	}
209	if (slink[0] != '\0')
210	name_list_add(&udev_device->link_list, slink, 0);
211	}
212	name_list_add(&udev_device->env_list, key, 0);
213	}
214
215	return udev_device;
216	}