1 /*
2  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #include "compat.h"
18 
19 #include <sys/types.h>
20 #include <sys/stat.h>
21 #include <sys/socket.h>
22 #include <sys/uio.h>
23 #include <sys/un.h>
24 
25 #include <netinet/in.h>
26 #include <net/if.h>
27 
28 #include <errno.h>
29 #include <stdlib.h>
30 #include <string.h>
31 #include <unistd.h>
32 
33 #include "control.h"
34 #include "kamid.h"
35 #include "listener.h"
36 #include "log.h"
37 #include "utils.h"
38 
39 #define	CONTROL_BACKLOG	5
40 
41 struct {
42 	struct event	ev;
43 	struct event	evt;
44 	int		fd;
45 } control_state = {.fd = -1};
46 
47 struct ctl_conn {
48 	TAILQ_ENTRY(ctl_conn)	entry;
49 	struct imsgev		iev;
50 };
51 
52 TAILQ_HEAD(ctl_conns, ctl_conn)	ctl_conns = TAILQ_HEAD_INITIALIZER(ctl_conns);
53 
54 struct ctl_conn	*control_connbyfd(int);
55 struct ctl_conn	*control_connbypid(pid_t);
56 void		 control_close(int);
57 
58 int
59 control_init(const char *path)
60 {
61 	struct sockaddr_un	 sun;
62 	int			 fd;
63 	mode_t			 old_umask;
64 
65 	if ((fd = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK,
66 	    0)) == -1) {
67 		log_warn("%s: socket", __func__);
68 		return (-1);
69 	}
70 
71 	memset(&sun, 0, sizeof(sun));
72 	sun.sun_family = AF_UNIX;
73 	strlcpy(sun.sun_path, path, sizeof(sun.sun_path));
74 
75 	if (unlink(path) == -1)
76 		if (errno != ENOENT) {
77 			log_warn("%s: unlink %s", __func__, path);
78 			close(fd);
79 			return (-1);
80 		}
81 
82 	old_umask = umask(S_IXUSR|S_IXGRP|S_IWOTH|S_IROTH|S_IXOTH);
83 	if (bind(fd, (struct sockaddr *)&sun, sizeof(sun)) == -1) {
84 		log_warn("%s: bind: %s", __func__, path);
85 		close(fd);
86 		umask(old_umask);
87 		return (-1);
88 	}
89 	umask(old_umask);
90 
91 	if (chmod(path, S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP) == -1) {
92 		log_warn("%s: chmod", __func__);
93 		close(fd);
94 		(void)unlink(path);
95 		return (-1);
96 	}
97 
98 	return (fd);
99 }
100 
101 int
102 control_listen(int fd)
103 {
104 	if (control_state.fd != -1)
105 		fatalx("%s: received unexpected controlsock", __func__);
106 
107 	control_state.fd = fd;
108 	if (listen(control_state.fd, CONTROL_BACKLOG) == -1) {
109 		log_warn("%s: listen", __func__);
110 		return (-1);
111 	}
112 
113 	event_set(&control_state.ev, control_state.fd, EV_READ,
114 	    control_accept, NULL);
115 	event_add(&control_state.ev, NULL);
116 	evtimer_set(&control_state.evt, control_accept, NULL);
117 
118 	return (0);
119 }
120 
121 void
122 control_accept(int listenfd, short event, void *bula)
123 {
124 	int			 connfd;
125 	socklen_t		 len;
126 	struct sockaddr_un	 sun;
127 	struct ctl_conn		*c;
128 
129 	event_add(&control_state.ev, NULL);
130 	if ((event & EV_TIMEOUT))
131 		return;
132 
133 	len = sizeof(sun);
134 	if ((connfd = accept4(listenfd, (struct sockaddr *)&sun, &len,
135 	    SOCK_CLOEXEC | SOCK_NONBLOCK)) == -1) {
136 		/*
137 		 * Pause accept if we are out of file descriptors, or
138 		 * libevent will haunt us here too.
139 		 */
140 		if (errno == ENFILE || errno == EMFILE) {
141 			struct timeval evtpause = { 1, 0 };
142 
143 			event_del(&control_state.ev);
144 			evtimer_add(&control_state.evt, &evtpause);
145 		} else if (errno != EWOULDBLOCK && errno != EINTR &&
146 		    errno != ECONNABORTED)
147 			log_warn("%s: accept4", __func__);
148 		return;
149 	}
150 
151 	if ((c = calloc(1, sizeof(struct ctl_conn))) == NULL) {
152 		log_warn("%s: calloc", __func__);
153 		close(connfd);
154 		return;
155 	}
156 
157 	imsg_init(&c->iev.ibuf, connfd);
158 	c->iev.handler = control_dispatch_imsg;
159 	c->iev.events = EV_READ;
160 	event_set(&c->iev.ev, c->iev.ibuf.fd, c->iev.events,
161 	    c->iev.handler, &c->iev);
162 	event_add(&c->iev.ev, NULL);
163 
164 	TAILQ_INSERT_TAIL(&ctl_conns, c, entry);
165 }
166 
167 struct ctl_conn *
168 control_connbyfd(int fd)
169 {
170 	struct ctl_conn	*c;
171 
172 	TAILQ_FOREACH(c, &ctl_conns, entry) {
173 		if (c->iev.ibuf.fd == fd)
174 			break;
175 	}
176 
177 	return (c);
178 }
179 
180 struct ctl_conn *
181 control_connbypid(pid_t pid)
182 {
183 	struct ctl_conn	*c;
184 
185 	TAILQ_FOREACH(c, &ctl_conns, entry) {
186 		if (c->iev.ibuf.pid == pid)
187 			break;
188 	}
189 
190 	return (c);
191 }
192 
193 void
194 control_close(int fd)
195 {
196 	struct ctl_conn	*c;
197 
198 	if ((c = control_connbyfd(fd)) == NULL) {
199 		log_warnx("%s: fd %d: not found", __func__, fd);
200 		return;
201 	}
202 
203 	msgbuf_clear(&c->iev.ibuf.w);
204 	TAILQ_REMOVE(&ctl_conns, c, entry);
205 
206 	event_del(&c->iev.ev);
207 	close(c->iev.ibuf.fd);
208 
209 	/* Some file descriptors are available again. */
210 	if (evtimer_pending(&control_state.evt, NULL)) {
211 		evtimer_del(&control_state.evt);
212 		event_add(&control_state.ev, NULL);
213 	}
214 
215 	free(c);
216 }
217 
218 void
219 control_dispatch_imsg(int fd, short event, void *bula)
220 {
221 	struct ctl_conn	*c;
222 	struct imsg	 imsg;
223 	ssize_t		 n;
224 	int		 verbose;
225 
226 	if ((c = control_connbyfd(fd)) == NULL) {
227 		log_warnx("%s: fd %d: not found", __func__, fd);
228 		return;
229 	}
230 
231 	if (event & EV_READ) {
232 		if (((n = imsg_read(&c->iev.ibuf)) == -1 && errno != EAGAIN) ||
233 		    n == 0) {
234 			control_close(fd);
235 			return;
236 		}
237 	}
238 	if (event & EV_WRITE) {
239 		if (msgbuf_write(&c->iev.ibuf.w) <= 0 && errno != EAGAIN) {
240 			control_close(fd);
241 			return;
242 		}
243 	}
244 
245 	for (;;) {
246 		if ((n = imsg_get(&c->iev.ibuf, &imsg)) == -1) {
247 			control_close(fd);
248 			return;
249 		}
250 		if (n == 0)
251 			break;
252 
253 		switch (imsg.hdr.type) {
254 		case IMSG_CTL_RELOAD:
255 			listener_imsg_compose_main(imsg.hdr.type, 0, NULL, 0);
256 			break;
257 		case IMSG_CTL_LOG_VERBOSE:
258 			if (IMSG_DATA_SIZE(imsg) != sizeof(verbose))
259 				break;
260 
261 			/* Forward to all other processes. */
262 			listener_imsg_compose_main(imsg.hdr.type, imsg.hdr.pid,
263 			    imsg.data, IMSG_DATA_SIZE(imsg));
264 
265 			/* XXX: send to every client? */
266 
267 			memcpy(&verbose, imsg.data, sizeof(verbose));
268 			log_setverbose(verbose);
269 			break;
270 		default:
271 			log_debug("%s: error handling imsg %d", __func__,
272 			    imsg.hdr.type);
273 			break;
274 		}
275 		imsg_free(&imsg);
276 	}
277 
278 	imsg_event_add(&c->iev);
279 }
280 
281 int
282 control_imsg_relay(struct imsg *imsg)
283 {
284 	struct ctl_conn	*c;
285 
286 	if ((c = control_connbypid(imsg->hdr.pid)) == NULL)
287 		return (0);
288 
289 	return (imsg_compose_event(&c->iev, imsg->hdr.type, 0, imsg->hdr.pid,
290 	    -1, imsg->data, IMSG_DATA_SIZE(*imsg)));
291 }