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 <fcntl.h>
30 #include <stdint.h>
31 #include <stdlib.h>
32 #include <string.h>
33 #include <unistd.h>
34 
35 #include "control.h"
36 #include "kamid.h"
37 #include "log.h"
38 #include "utils.h"
39 
40 #define	CONTROL_BACKLOG	5
41 
42 uint32_t peeridcnt;
43 
44 struct {
45 	struct event	ev;
46 	struct event	evt;
47 	int		fd;
48 } control_state = {.fd = -1};
49 
50 struct ctl_conn {
51 	TAILQ_ENTRY(ctl_conn)	entry;
52 	uint32_t		peerid;
53 	struct imsgev		iev;
54 };
55 
56 TAILQ_HEAD(ctl_conns, ctl_conn)	ctl_conns = TAILQ_HEAD_INITIALIZER(ctl_conns);
57 
58 struct ctl_conn	*control_connbyfd(int);
59 struct ctl_conn	*control_connbypeer(uint32_t);
60 struct ctl_conn	*control_connbypid(pid_t);
61 void		 control_close(int);
62 
63 int
64 control_init(const char *path)
65 {
66 	struct sockaddr_un	 sun;
67 	int			 fd;
68 	mode_t			 old_umask;
69 
70 	if ((fd = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK,
71 	    0)) == -1) {
72 		log_warn("%s: socket", __func__);
73 		return (-1);
74 	}
75 
76 	memset(&sun, 0, sizeof(sun));
77 	sun.sun_family = AF_UNIX;
78 	strlcpy(sun.sun_path, path, sizeof(sun.sun_path));
79 
80 	if (unlink(path) == -1)
81 		if (errno != ENOENT) {
82 			log_warn("%s: unlink %s", __func__, path);
83 			close(fd);
84 			return (-1);
85 		}
86 
87 	old_umask = umask(S_IXUSR|S_IXGRP|S_IWOTH|S_IROTH|S_IXOTH);
88 	if (bind(fd, (struct sockaddr *)&sun, sizeof(sun)) == -1) {
89 		log_warn("%s: bind: %s", __func__, path);
90 		close(fd);
91 		umask(old_umask);
92 		return (-1);
93 	}
94 	umask(old_umask);
95 
96 	if (chmod(path, S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP) == -1) {
97 		log_warn("%s: chmod", __func__);
98 		close(fd);
99 		(void)unlink(path);
100 		return (-1);
101 	}
102 
103 	return (fd);
104 }
105 
106 int
107 control_listen(int fd)
108 {
109 	if (control_state.fd != -1)
110 		fatalx("%s: received unexpected controlsock", __func__);
111 
112 	control_state.fd = fd;
113 	if (listen(control_state.fd, CONTROL_BACKLOG) == -1) {
114 		log_warn("%s: listen", __func__);
115 		return (-1);
116 	}
117 
118 	event_set(&control_state.ev, control_state.fd, EV_READ,
119 	    control_accept, NULL);
120 	event_add(&control_state.ev, NULL);
121 	evtimer_set(&control_state.evt, control_accept, NULL);
122 
123 	return (0);
124 }
125 
126 void
127 control_accept(int listenfd, short event, void *bula)
128 {
129 	int			 connfd, flags;
130 	socklen_t		 len;
131 	struct sockaddr_un	 sun;
132 	struct ctl_conn		*c;
133 
134 	event_add(&control_state.ev, NULL);
135 	if ((event & EV_TIMEOUT))
136 		return;
137 
138 	len = sizeof(sun);
139 	if ((connfd = accept(listenfd, (struct sockaddr *)&sun, &len)) == -1) {
140 		/*
141 		 * Pause accept if we are out of file descriptors, or
142 		 * libevent will haunt us here too.
143 		 */
144 		if (errno == ENFILE || errno == EMFILE) {
145 			struct timeval evtpause = { 1, 0 };
146 
147 			event_del(&control_state.ev);
148 			evtimer_add(&control_state.evt, &evtpause);
149 		} else if (errno != EWOULDBLOCK && errno != EINTR &&
150 		    errno != ECONNABORTED)
151 			log_warn("%s: accept4", __func__);
152 		return;
153 	}
154 
155 	if ((flags = fcntl(connfd, F_GETFL)) == -1) {
156 		log_warn("%s: fcntl F_GETFL", __func__);
157 		close(connfd);
158 		return;
159 	}
160 	flags |= O_NONBLOCK;
161 	if (fcntl(connfd, F_SETFL, flags) == -1 ||
162 	    fcntl(connfd, F_SETFD, FD_CLOEXEC) == -1) {
163 		log_warn("%s: can't set nonblock/cloexec", __func__);
164 		close(connfd);
165 		return;
166 	}
167 
168 	if ((c = calloc(1, sizeof(struct ctl_conn))) == NULL) {
169 		log_warn("%s: calloc", __func__);
170 		close(connfd);
171 		return;
172 	}
173 
174 	c->peerid = peeridcnt++;
175 	imsg_init(&c->iev.ibuf, connfd);
176 	c->iev.handler = control_dispatch_imsg;
177 	c->iev.events = EV_READ;
178 	event_set(&c->iev.ev, c->iev.ibuf.fd, c->iev.events,
179 	    c->iev.handler, &c->iev);
180 	event_add(&c->iev.ev, NULL);
181 
182 	TAILQ_INSERT_TAIL(&ctl_conns, c, entry);
183 }
184 
185 struct ctl_conn *
186 control_connbyfd(int fd)
187 {
188 	struct ctl_conn	*c;
189 
190 	TAILQ_FOREACH(c, &ctl_conns, entry) {
191 		if (c->iev.ibuf.fd == fd)
192 			break;
193 	}
194 
195 	return (c);
196 }
197 
198 struct ctl_conn *
199 control_connbypeer(uint32_t peerid)
200 {
201 	struct ctl_conn	*c;
202 
203 	TAILQ_FOREACH(c, &ctl_conns, entry) {
204 		if (c->peerid == peerid)
205 			break;
206 	}
207 
208 	return (c);
209 }
210 
211 struct ctl_conn *
212 control_connbypid(pid_t pid)
213 {
214 	struct ctl_conn	*c;
215 
216 	TAILQ_FOREACH(c, &ctl_conns, entry) {
217 		if (c->iev.ibuf.pid == pid)
218 			break;
219 	}
220 
221 	return (c);
222 }
223 
224 void
225 control_close(int fd)
226 {
227 	struct ctl_conn	*c;
228 
229 	if ((c = control_connbyfd(fd)) == NULL) {
230 		log_warnx("%s: fd %d: not found", __func__, fd);
231 		return;
232 	}
233 
234 	msgbuf_clear(&c->iev.ibuf.w);
235 	TAILQ_REMOVE(&ctl_conns, c, entry);
236 
237 	event_del(&c->iev.ev);
238 	close(c->iev.ibuf.fd);
239 
240 	/* Some file descriptors are available again. */
241 	if (evtimer_pending(&control_state.evt, NULL)) {
242 		evtimer_del(&control_state.evt);
243 		event_add(&control_state.ev, NULL);
244 	}
245 
246 	free(c);
247 }
248 
249 void
250 control_dispatch_imsg(int fd, short event, void *bula)
251 {
252 	struct ctl_conn	*c;
253 	struct imsg	 imsg;
254 	ssize_t		 n;
255 
256 	if ((c = control_connbyfd(fd)) == NULL) {
257 		log_warnx("%s: fd %d: not found", __func__, fd);
258 		return;
259 	}
260 
261 	if (event & EV_READ) {
262 		if (((n = imsg_read(&c->iev.ibuf)) == -1 && errno != EAGAIN) ||
263 		    n == 0) {
264 			control_close(fd);
265 			return;
266 		}
267 	}
268 	if (event & EV_WRITE) {
269 		if (msgbuf_write(&c->iev.ibuf.w) <= 0 && errno != EAGAIN) {
270 			control_close(fd);
271 			return;
272 		}
273 	}
274 
275 	for (;;) {
276 		if ((n = imsg_get(&c->iev.ibuf, &imsg)) == -1) {
277 			control_close(fd);
278 			return;
279 		}
280 		if (n == 0)
281 			break;
282 
283 		switch (imsg.hdr.type) {
284 		case IMSG_CTL_RELOAD:
285 			if (main_reload() == -1)
286 				log_warnx("configuration reload failed");
287 			break;
288 		case IMSG_CTL_DEBUG:
289 			main_imsg_compose_listener(IMSG_CTL_DEBUG, -1,
290 			    c->peerid, NULL, 0);
291 			break;
292 		case IMSG_CTL_LOG_VERBOSE:
293 			if (IMSG_DATA_SIZE(imsg) != sizeof(verbose))
294 				break;
295 
296 			/* Forward to all other processes. */
297 			main_imsg_compose_listener(imsg.hdr.type, -1,
298 			    0, imsg.data, IMSG_DATA_SIZE(imsg));
299 
300 			memcpy(&verbose, imsg.data, sizeof(verbose));
301 			log_setverbose(verbose);
302 			break;
303 		default:
304 			log_debug("%s: error handling imsg %d", __func__,
305 			    imsg.hdr.type);
306 			break;
307 		}
308 		imsg_free(&imsg);
309 	}
310 
311 	imsg_event_add(&c->iev);
312 }
313 
314 int
315 control_imsg_relay(struct imsg *imsg)
316 {
317 	struct ctl_conn	*c;
318 
319 	if ((c = control_connbypeer(imsg->hdr.peerid)) == NULL)
320 		return (0);
321 
322 	return (imsg_compose_event(&c->iev, imsg->hdr.type, 0, imsg->hdr.pid,
323 	    -1, imsg->data, IMSG_DATA_SIZE(*imsg)));
324 }