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