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