1 /*	$OpenBSD: control.c,v 1.4 2021/08/01 09:07:03 florian Exp $	*/
2 
3 /*
4  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
5  *
6  * Permission to use, copy, modify, and distribute this software for any
7  * purpose with or without fee is hereby granted, provided that the above
8  * copyright notice and this permission notice appear in all copies.
9  *
10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17  */
18 
19 #include "compat.h"
20 
21 #include <sys/types.h>
22 #include <sys/stat.h>
23 #include <sys/socket.h>
24 #include <sys/uio.h>
25 #include <sys/un.h>
26 
27 #include <errno.h>
28 #include <stdlib.h>
29 #include <string.h>
30 #include <unistd.h>
31 
32 #include "control.h"
33 #include "minibuffer.h"
34 #include "session.h"
35 #include "telescope.h"
36 #include "utils.h"
37 #include "ui.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 struct ctl_conn	*control_connbyfd(int);
53 struct ctl_conn	*control_connbypid(pid_t);
54 void		 control_close(int);
55 
56 TAILQ_HEAD(ctl_conns, ctl_conn) ctl_conns = TAILQ_HEAD_INITIALIZER(ctl_conns);
57 
58 int
59 control_init(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 		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 			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 		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 		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 	control_state.fd = fd;
105 	if (listen(control_state.fd, CONTROL_BACKLOG) == -1) {
106 		warn("%s: listen", __func__);
107 		return (-1);
108 	}
109 
110 	event_set(&control_state.ev, control_state.fd, EV_READ,
111 	    control_accept, NULL);
112 	event_add(&control_state.ev, NULL);
113 	evtimer_set(&control_state.evt, control_accept, NULL);
114 
115 	return (0);
116 }
117 
118 void
119 control_accept(int listenfd, short event, void *bula)
120 {
121 	int			 connfd;
122 	socklen_t		 len;
123 	struct sockaddr_un	 sun;
124 	struct ctl_conn		*c;
125 
126 	event_add(&control_state.ev, NULL);
127 	if ((event & EV_TIMEOUT))
128 		return;
129 
130 	len = sizeof(sun);
131 	if ((connfd = accept4(listenfd, (struct sockaddr *)&sun, &len,
132 	    SOCK_CLOEXEC | SOCK_NONBLOCK)) == -1) {
133 		/*
134 		 * Pause accept if we are out of file descriptors, or
135 		 * libevent will haunt us here too.
136 		 */
137 		if (errno == ENFILE || errno == EMFILE) {
138 			struct timeval evtpause = { 1, 0 };
139 
140 			event_del(&control_state.ev);
141 			evtimer_add(&control_state.evt, &evtpause);
142 		} else if (errno != EWOULDBLOCK && errno != EINTR &&
143 		    errno != ECONNABORTED)
144 			message("%s: accept4: %s", __func__, strerror(errno));
145 		return;
146 	}
147 
148 	if ((c = calloc(1, sizeof(struct ctl_conn))) == NULL) {
149 		message("%s: calloc: %s", __func__, strerror(errno));
150 		close(connfd);
151 		return;
152 	}
153 
154 	imsg_init(&c->iev.ibuf, connfd);
155 	c->iev.handler = control_dispatch_imsg;
156 	c->iev.events = EV_READ;
157 	event_set(&c->iev.ev, c->iev.ibuf.fd, c->iev.events,
158 	    c->iev.handler, &c->iev);
159 	event_add(&c->iev.ev, NULL);
160 
161 	TAILQ_INSERT_TAIL(&ctl_conns, c, entry);
162 }
163 
164 struct ctl_conn *
165 control_connbyfd(int fd)
166 {
167 	struct ctl_conn	*c;
168 
169 	TAILQ_FOREACH(c, &ctl_conns, entry) {
170 		if (c->iev.ibuf.fd == fd)
171 			break;
172 	}
173 
174 	return (c);
175 }
176 
177 struct ctl_conn *
178 control_connbypid(pid_t pid)
179 {
180 	struct ctl_conn	*c;
181 
182 	TAILQ_FOREACH(c, &ctl_conns, entry) {
183 		if (c->iev.ibuf.pid == pid)
184 			break;
185 	}
186 
187 	return (c);
188 }
189 
190 void
191 control_close(int fd)
192 {
193 	struct ctl_conn	*c;
194 
195 	if ((c = control_connbyfd(fd)) == NULL) {
196 		message("%s: fd %d: not found", __func__, fd);
197 		return;
198 	}
199 
200 	msgbuf_clear(&c->iev.ibuf.w);
201 	TAILQ_REMOVE(&ctl_conns, c, entry);
202 
203 	event_del(&c->iev.ev);
204 	close(c->iev.ibuf.fd);
205 
206 	/* Some file descriptors are available again. */
207 	if (evtimer_pending(&control_state.evt, NULL)) {
208 		evtimer_del(&control_state.evt);
209 		event_add(&control_state.ev, NULL);
210 	}
211 
212 	free(c);
213 }
214 
215 void
216 control_dispatch_imsg(int fd, short event, void *bula)
217 {
218 	struct ctl_conn	*c;
219 	struct imsg	 imsg;
220 	ssize_t		 n;
221 
222 	if ((c = control_connbyfd(fd)) == NULL) {
223 		message("%s: fd %d: not found", __func__, fd);
224 		return;
225 	}
226 
227 	if (event & EV_READ) {
228 		if (((n = imsg_read(&c->iev.ibuf)) == -1 && errno != EAGAIN) ||
229 		    n == 0) {
230 			control_close(fd);
231 			return;
232 		}
233 	}
234 	if (event & EV_WRITE) {
235 		if (msgbuf_write(&c->iev.ibuf.w) <= 0 && errno != EAGAIN) {
236 			control_close(fd);
237 			return;
238 		}
239 	}
240 
241 	for (;;) {
242 		if ((n = imsg_get(&c->iev.ibuf, &imsg)) == -1) {
243 			control_close(fd);
244 			return;
245 		}
246 		if (n == 0)
247 			break;
248 
249 		switch (imsg.hdr.type) {
250 		case IMSG_CTL_OPEN_URL: {
251 			char uri[GEMINI_URL_LEN] = { 0 };
252 
253 			if (IMSG_DATA_SIZE(imsg) > sizeof(uri)-1)
254 				break;
255 			memcpy(uri, imsg.data, sizeof(uri));
256 			if (uri[IMSG_DATA_SIZE(imsg)-1] != '\0')
257 				break;
258 
259 			new_tab(uri, NULL, NULL);
260 			ui_on_tab_refresh(current_tab);
261 			break;
262 		}
263 		default:
264 			message("%s: error handling imsg %d", __func__,
265 			    imsg.hdr.type);
266 			break;
267 		}
268 		imsg_free(&imsg);
269 	}
270 
271 	imsg_event_add(&c->iev);
272 }
273 
274 int
275 control_imsg_relay(struct imsg *imsg)
276 {
277 	struct ctl_conn	*c;
278 
279 	if ((c = control_connbypid(imsg->hdr.pid)) == NULL)
280 		return (0);
281 
282 	return (imsg_compose_event(&c->iev, imsg->hdr.type, 0, imsg->hdr.pid,
283 	    -1, imsg->data, IMSG_DATA_SIZE(*imsg)));
284 }