1/*
2 * dhcpcd - DHCP client daemon
3 * Copyright (c) 2006-2009 Roy Marples <roy@marples.name>
4 * All rights reserved
5
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28#include <linux/socket.h>
29#include <sys/stat.h>
30#include <sys/un.h>
31
32#include <errno.h>
33#include <stdio.h>
34#include <stdlib.h>
35#include <string.h>
36#include <time.h>
37#include <unistd.h>
38
39#include "config.h"
40#include "common.h"
41#include "dhcpcd.h"
42#include "control.h"
43#include "eloop.h"
44
45static int fd = -1;
46static char buffer[1024];
47static char *argvp[255];
48
49struct sockaddr_un sun;
50struct fd_list *fds = NULL;
51
52static void
53remove_control_data(void *arg)
54{
55	struct fd_list *l, *last = NULL;
56
57	for (l = fds; l != NULL; l = l->next) {
58		if (l == arg) {
59			close(l->fd);
60			delete_event(l->fd);
61			if (last == NULL)
62				fds = l->next;
63			else
64				last->next = l->next;
65			free(l);
66			break;
67		}
68		last = l;
69	}
70}
71
72static void
73handle_control_data(void *arg)
74{
75	struct fd_list *l = arg;
76	ssize_t bytes;
77	int argc;
78	char *e, *p;
79	char **ap;
80
81	bytes = read(l->fd, buffer, sizeof(buffer) - 1);
82	if (bytes == -1 || bytes == 0) {
83		remove_control_data(l);
84		return;
85	}
86	buffer[bytes] = '\0';
87	p = buffer;
88	e = buffer + bytes;
89	argc = 0;
90	ap = argvp;
91	while (p < e && (size_t)argc < sizeof(argvp)) {
92		argc++;
93		*ap++ = p;
94		p += strlen(p) + 1;
95	}
96	handle_args(l, argc, argvp);
97}
98
99/* ARGSUSED */
100static void
101handle_control(_unused void *arg)
102{
103	struct sockaddr_un run;
104	socklen_t len;
105	struct fd_list *l;
106	int f;
107
108	len = sizeof(run);
109	if ((f = accept(fd, (struct sockaddr *)&run, &len)) == -1)
110		return;
111	l = xmalloc(sizeof(*l));
112	l->fd = f;
113	l->listener = 0;
114	l->next = fds;
115	fds = l;
116	add_event(l->fd, handle_control_data, l);
117}
118
119static int
120make_sock(void)
121{
122	if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1)
123		return -1;
124	memset(&sun, 0, sizeof(sun));
125	sun.sun_family = AF_UNIX;
126	strlcpy(sun.sun_path, CONTROLSOCKET, sizeof(sun.sun_path));
127	return sizeof(sun.sun_family) + strlen(sun.sun_path) + 1;
128}
129
130int
131start_control(void)
132{
133	int len;
134
135	if ((len = make_sock()) == -1)
136		return -1;
137	unlink(CONTROLSOCKET);
138	if (bind(fd, (struct sockaddr *)&sun, len) == -1 ||
139	    chmod(CONTROLSOCKET,
140		S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP) == -1 ||
141	    set_cloexec(fd) == -1 ||
142	    set_nonblock(fd) == -1 ||
143	    listen(fd, sizeof(fds)) == -1)
144	{
145		close(fd);
146		return -1;
147	}
148	add_event(fd, handle_control, NULL);
149	return fd;
150}
151
152int
153stop_control(void)
154{
155	int retval = 0;
156	struct fd_list *l, *ll;
157
158	delete_event(fd);
159	if (shutdown(fd, SHUT_RDWR) == -1)
160		retval = 1;
161	fd = -1;
162	if (unlink(CONTROLSOCKET) == -1)
163		retval = -1;
164
165	l = fds;
166	while (l != NULL) {
167		ll = l->next;
168		delete_event(l->fd);
169		shutdown(l->fd, SHUT_RDWR);
170		free(l);
171		l = ll;
172	}
173
174	return retval;
175}
176
177int
178open_control(void)
179{
180	int len;
181
182	if ((len = make_sock()) == -1)
183		return -1;
184	return connect(fd, (struct sockaddr *)&sun, len);
185}
186
187int
188send_control(int argc, char * const *argv)
189{
190	char *p = buffer;
191	int i;
192	size_t len;
193
194	if (argc > 255) {
195		errno = ENOBUFS;
196		return -1;
197	}
198	for (i = 0; i < argc; i++) {
199		len = strlen(argv[i]) + 1;
200		if ((p - buffer) + len > sizeof(buffer)) {
201			errno = ENOBUFS;
202			return -1;
203		}
204		memcpy(p, argv[i], len);
205		p += len;
206	}
207	return write(fd, buffer, p - buffer);
208}
209