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 "ev.h"
34 #include "imsgev.h"
35 #include "minibuffer.h"
36 #include "telescope.h"
37 #include "utils.h"
38 #include "ui.h"
39 #include "xwrapper.h"
40 
41 #define	CONTROL_BACKLOG	5
42 
43 struct {
44 	unsigned long	timeout;
45 	int		fd;
46 } control_state = {.fd = -1};
47 
48 struct ctl_conn {
49 	TAILQ_ENTRY(ctl_conn)	entry;
50 	struct imsgev		iev;
51 };
52 
53 struct ctl_conn	*control_connbyfd(int);
54 struct ctl_conn	*control_connbypid(pid_t);
55 void		 control_close(int);
56 
57 TAILQ_HEAD(ctl_conns, ctl_conn) ctl_conns = TAILQ_HEAD_INITIALIZER(ctl_conns);
58 
59 int
60 control_init(char *path)
61 {
62 	struct sockaddr_un	 sun;
63 	int			 fd;
64 	mode_t			 old_umask;
65 
66 	if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
67 		warn("%s: socket", __func__);
68 		return (-1);
69 	}
70 
71 	if (!mark_nonblock_cloexec(fd)) {
72 		close(fd);
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 			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 		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 		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 	control_state.fd = fd;
110 	if (listen(control_state.fd, CONTROL_BACKLOG) == -1) {
111 		warn("%s: listen", __func__);
112 		return (-1);
113 	}
114 
115 	ev_add(control_state.fd, EV_READ, control_accept, NULL);
116 	return (0);
117 }
118 
119 void
120 control_accept(int listenfd, int event, void *bula)
121 {
122 	int			 connfd;
123 	socklen_t		 len;
124 	struct sockaddr_un	 sun;
125 	struct ctl_conn		*c;
126 
127 	ev_add(control_state.fd, EV_READ, control_accept, NULL);
128 	if ((event & EV_TIMEOUT))
129 		return;
130 
131 	len = sizeof(sun);
132 	if ((connfd = accept(listenfd, (struct sockaddr *)&sun, &len)) == -1) {
133 		/*
134 		 * Pause accept if we are out of file descriptors, or
135 		 * ev will haunt us here too.
136 		 */
137 		if (errno == ENFILE || errno == EMFILE) {
138 			struct timeval evtpause = { 1, 0 };
139 
140 			ev_del(control_state.fd);
141 			control_state.timeout = ev_timer(&evtpause,
142 			    control_accept, NULL);
143 		} else if (errno != EWOULDBLOCK && errno != EINTR &&
144 		    errno != ECONNABORTED)
145 			message("%s: accept4: %s", __func__, strerror(errno));
146 		return;
147 	}
148 
149 	if (!mark_nonblock_cloexec(connfd)) {
150 		message("%s: mark_nonblock_cloexec: %s", __func__,
151 		    strerror(errno));
152 		close(connfd);
153 		return;
154 	}
155 
156 	c = xcalloc(1, sizeof(struct ctl_conn));
157 
158 	if (imsgbuf_init(&c->iev.ibuf, connfd) == -1) {
159 		message("%s: ev_add: %s", __func__, strerror(errno));
160 		close(connfd);
161 		free(c);
162 		return;
163 	}
164 
165 	c->iev.handler = control_dispatch_imsg;
166 	c->iev.events = EV_READ;
167 	if (ev_add(connfd, c->iev.events, c->iev.handler, &c->iev) == -1) {
168 		message("%s: ev_add: %s", __func__, strerror(errno));
169 		close(connfd);
170 		free(c);
171 		return;
172 	}
173 
174 	TAILQ_INSERT_TAIL(&ctl_conns, c, entry);
175 }
176 
177 struct ctl_conn *
178 control_connbyfd(int fd)
179 {
180 	struct ctl_conn	*c;
181 
182 	TAILQ_FOREACH(c, &ctl_conns, entry) {
183 		if (c->iev.ibuf.fd == fd)
184 			break;
185 	}
186 
187 	return (c);
188 }
189 
190 struct ctl_conn *
191 control_connbypid(pid_t pid)
192 {
193 	struct ctl_conn	*c;
194 
195 	TAILQ_FOREACH(c, &ctl_conns, entry) {
196 		if (c->iev.ibuf.pid == pid)
197 			break;
198 	}
199 
200 	return (c);
201 }
202 
203 void
204 control_close(int fd)
205 {
206 	struct ctl_conn	*c;
207 
208 	if ((c = control_connbyfd(fd)) == NULL) {
209 		message("%s: fd %d: not found", __func__, fd);
210 		return;
211 	}
212 
213 	ev_del(c->iev.ibuf.fd);
214 	close(c->iev.ibuf.fd);
215 
216 	imsgbuf_clear(&c->iev.ibuf);
217 	TAILQ_REMOVE(&ctl_conns, c, entry);
218 
219 	free(c);
220 
221 	/* Some file descriptors are available again. */
222 	if (ev_timer_pending(control_state.timeout)) {
223 		ev_timer_cancel(control_state.timeout);
224 		control_state.timeout = 0;
225 		ev_add(control_state.fd, EV_READ, control_accept, NULL);
226 	}
227 }
228 
229 void
230 control_dispatch_imsg(int fd, int event, void *bula)
231 {
232 	struct ctl_conn	*c;
233 	struct imsg	 imsg;
234 	ssize_t		 n;
235 
236 	if ((c = control_connbyfd(fd)) == NULL) {
237 		message("%s: fd %d: not found", __func__, fd);
238 		return;
239 	}
240 
241 	if (event & EV_READ) {
242 		if (imsgbuf_read(&c->iev.ibuf) == -1) {
243 			control_close(fd);
244 			return;
245 		}
246 	}
247 	if (event & EV_WRITE) {
248 		if (imsgbuf_write(&c->iev.ibuf) == -1) {
249 			control_close(fd);
250 			return;
251 		}
252 	}
253 
254 	for (;;) {
255 		if ((n = imsg_get(&c->iev.ibuf, &imsg)) == -1) {
256 			control_close(fd);
257 			return;
258 		}
259 		if (n == 0)
260 			break;
261 
262 		switch (imsg.hdr.type) {
263 		case IMSG_CTL_OPEN_URL: {
264 			static char uri[GEMINI_URL_LEN];
265 
266 			if (IMSG_DATA_SIZE(imsg) >= sizeof(uri))
267 				break;
268 			memset(uri, 0, sizeof(uri));
269 			memcpy(uri, imsg.data, sizeof(uri));
270 			if (uri[IMSG_DATA_SIZE(imsg)-1] != '\0')
271 				break;
272 
273 			ui_remotely_open_link(uri);
274 			break;
275 		}
276 		default:
277 			message("%s: error handling imsg %d", __func__,
278 			    imsg.hdr.type);
279 			break;
280 		}
281 		imsg_free(&imsg);
282 	}
283 
284 	imsg_event_add(&c->iev);
285 }