op public repos

Blob

Date:: Sun Jan 7 18:27:41 2024 UTC
Message:: sync imsg
Actions:: History | Blame | Raw File
1 /*	$OpenBSD: imsg.c,v 1.23 2023/12/12 15:47:41 claudio Exp $	*/
2 
3 /*
4  * Copyright (c) 2023 Claudio Jeker <claudio@openbsd.org>
5  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
6  *
7  * Permission to use, copy, modify, and distribute this software for any
8  * purpose with or without fee is hereby granted, provided that the above
9  * copyright notice and this permission notice appear in all copies.
10  *
11  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
12  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
13  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
14  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
15  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
16  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
17  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18  */
19 
20 #include "../config.h"
21 
22 #include <sys/types.h>
23 #include <sys/socket.h>
24 #include <sys/uio.h>
25 
26 #include <errno.h>
27 #include <stdlib.h>
28 #include <string.h>
29 #include <unistd.h>
30 
31 #include "imsg.h"
32 
33 struct imsg_fd {
34 	TAILQ_ENTRY(imsg_fd)	entry;
35 	int			fd;
36 };
37 
38 int	 imsg_fd_overhead = 0;
39 
40 static int	 imsg_dequeue_fd(struct imsgbuf *);
41 
42 void
43 imsg_init(struct imsgbuf *imsgbuf, int fd)
44 {
45 	msgbuf_init(&imsgbuf->w);
46 	memset(&imsgbuf->r, 0, sizeof(imsgbuf->r));
47 	imsgbuf->fd = fd;
48 	imsgbuf->w.fd = fd;
49 	imsgbuf->pid = getpid();
50 	TAILQ_INIT(&imsgbuf->fds);
51 }
52 
53 ssize_t
54 imsg_read(struct imsgbuf *imsgbuf)
55 {
56 	struct msghdr		 msg;
57 	struct cmsghdr		*cmsg;
58 	union {
59 		struct cmsghdr hdr;
60 		char	buf[CMSG_SPACE(sizeof(int) * 1)];
61 	} cmsgbuf;
62 	struct iovec		 iov;
63 	ssize_t			 n = -1;
64 	int			 fd;
65 	struct imsg_fd		*ifd;
66 
67 	memset(&msg, 0, sizeof(msg));
68 	memset(&cmsgbuf, 0, sizeof(cmsgbuf));
69 
70 	iov.iov_base = imsgbuf->r.buf + imsgbuf->r.wpos;
71 	iov.iov_len = sizeof(imsgbuf->r.buf) - imsgbuf->r.wpos;
72 	msg.msg_iov = &iov;
73 	msg.msg_iovlen = 1;
74 	msg.msg_control = &cmsgbuf.buf;
75 	msg.msg_controllen = sizeof(cmsgbuf.buf);
76 
77 	if ((ifd = calloc(1, sizeof(struct imsg_fd))) == NULL)
78 		return (-1);
79 
80 again:
81 	if (getdtablecount() + imsg_fd_overhead +
82 	    (int)((CMSG_SPACE(sizeof(int))-CMSG_SPACE(0))/sizeof(int))
83 	    >= getdtablesize()) {
84 		errno = EAGAIN;
85 		free(ifd);
86 		return (-1);
87 	}
88 
89 	if ((n = recvmsg(imsgbuf->fd, &msg, 0)) == -1) {
90 		if (errno == EINTR)
91 			goto again;
92 		goto fail;
93 	}
94 
95 	imsgbuf->r.wpos += n;
96 
97 	for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL;
98 	    cmsg = CMSG_NXTHDR(&msg, cmsg)) {
99 		if (cmsg->cmsg_level == SOL_SOCKET &&
100 		    cmsg->cmsg_type == SCM_RIGHTS) {
101 			int i;
102 			int j;
103 
104 			/*
105 			 * We only accept one file descriptor.  Due to C
106 			 * padding rules, our control buffer might contain
107 			 * more than one fd, and we must close them.
108 			 */
109 			j = ((char *)cmsg + cmsg->cmsg_len -
110 			    (char *)CMSG_DATA(cmsg)) / sizeof(int);
111 			for (i = 0; i < j; i++) {
112 				fd = ((int *)CMSG_DATA(cmsg))[i];
113 				if (ifd != NULL) {
114 					ifd->fd = fd;
115 					TAILQ_INSERT_TAIL(&imsgbuf->fds, ifd,
116 					    entry);
117 					ifd = NULL;
118 				} else
119 					close(fd);
120 			}
121 		}
122 		/* we do not handle other ctl data level */
123 	}
124 
125 fail:
126 	free(ifd);
127 	return (n);
128 }
129 
130 ssize_t
131 imsg_get(struct imsgbuf *imsgbuf, struct imsg *imsg)
132 {
133 	struct imsg		 m;
134 	size_t			 av, left, datalen;
135 
136 	av = imsgbuf->r.wpos;
137 
138 	if (IMSG_HEADER_SIZE > av)
139 		return (0);
140 
141 	memcpy(&m.hdr, imsgbuf->r.buf, sizeof(m.hdr));
142 	if (m.hdr.len < IMSG_HEADER_SIZE ||
143 	    m.hdr.len > MAX_IMSGSIZE) {
144 		errno = ERANGE;
145 		return (-1);
146 	}
147 	if (m.hdr.len > av)
148 		return (0);
149 
150 	m.fd = -1;
151 	m.buf = NULL;
152 	m.data = NULL;
153 
154 	datalen = m.hdr.len - IMSG_HEADER_SIZE;
155 	imsgbuf->r.rptr = imsgbuf->r.buf + IMSG_HEADER_SIZE;
156 	if (datalen != 0) {
157 		if ((m.buf = ibuf_open(datalen)) == NULL)
158 			return (-1);
159 		if (ibuf_add(m.buf, imsgbuf->r.rptr, datalen) == -1) {
160 			/* this should never fail */
161 			ibuf_free(m.buf);
162 			return (-1);
163 		}
164 		m.data = ibuf_data(m.buf);
165 	}
166 
167 	if (m.hdr.flags & IMSGF_HASFD)
168 		m.fd = imsg_dequeue_fd(imsgbuf);
169 
170 	if (m.hdr.len < av) {
171 		left = av - m.hdr.len;
172 		memmove(&imsgbuf->r.buf, imsgbuf->r.buf + m.hdr.len, left);
173 		imsgbuf->r.wpos = left;
174 	} else
175 		imsgbuf->r.wpos = 0;
176 
177 	*imsg = m;
178 	return (datalen + IMSG_HEADER_SIZE);
179 }
180 
181 int
182 imsg_get_ibuf(struct imsg *imsg, struct ibuf *ibuf)
183 {
184 	if (imsg->buf == NULL) {
185 		errno = EBADMSG;
186 		return (-1);
187 	}
188 	return ibuf_get_ibuf(imsg->buf, ibuf_size(imsg->buf), ibuf);
189 }
190 
191 int
192 imsg_get_data(struct imsg *imsg, void *data, size_t len)
193 {
194 	if (len == 0) {
195 		errno = EINVAL;
196 		return (-1);
197 	}
198 	if (imsg->buf == NULL || ibuf_size(imsg->buf) != len) {
199 		errno = EBADMSG;
200 		return (-1);
201 	}
202 	return ibuf_get(imsg->buf, data, len);
203 }
204 
205 int
206 imsg_get_fd(struct imsg *imsg)
207 {
208 	int fd = imsg->fd;
209 
210 	imsg->fd = -1;
211 	return fd;
212 }
213 
214 uint32_t
215 imsg_get_id(struct imsg *imsg)
216 {
217 	return (imsg->hdr.peerid);
218 }
219 
220 size_t
221 imsg_get_len(struct imsg *imsg)
222 {
223 	if (imsg->buf == NULL)
224 		return 0;
225 	return ibuf_size(imsg->buf);
226 }
227 
228 pid_t
229 imsg_get_pid(struct imsg *imsg)
230 {
231 	return (imsg->hdr.pid);
232 }
233 
234 uint32_t
235 imsg_get_type(struct imsg *imsg)
236 {
237 	return (imsg->hdr.type);
238 }
239 
240 int
241 imsg_compose(struct imsgbuf *imsgbuf, uint32_t type, uint32_t id, pid_t pid,
242     int fd, const void *data, size_t datalen)
243 {
244 	struct ibuf	*wbuf;
245 
246 	if ((wbuf = imsg_create(imsgbuf, type, id, pid, datalen)) == NULL)
247 		return (-1);
248 
249 	if (imsg_add(wbuf, data, datalen) == -1)
250 		return (-1);
251 
252 	ibuf_fd_set(wbuf, fd);
253 	imsg_close(imsgbuf, wbuf);
254 
255 	return (1);
256 }
257 
258 int
259 imsg_composev(struct imsgbuf *imsgbuf, uint32_t type, uint32_t id, pid_t pid,
260     int fd, const struct iovec *iov, int iovcnt)
261 {
262 	struct ibuf	*wbuf;
263 	int		 i;
264 	size_t		 datalen = 0;
265 
266 	for (i = 0; i < iovcnt; i++)
267 		datalen += iov[i].iov_len;
268 
269 	if ((wbuf = imsg_create(imsgbuf, type, id, pid, datalen)) == NULL)
270 		return (-1);
271 
272 	for (i = 0; i < iovcnt; i++)
273 		if (imsg_add(wbuf, iov[i].iov_base, iov[i].iov_len) == -1)
274 			return (-1);
275 
276 	ibuf_fd_set(wbuf, fd);
277 	imsg_close(imsgbuf, wbuf);
278 
279 	return (1);
280 }
281 
282 /*
283  * Enqueue imsg with payload from ibuf buf. fd passing is not possible 
284  * with this function.
285  */
286 int
287 imsg_compose_ibuf(struct imsgbuf *imsgbuf, uint32_t type, uint32_t id,
288     pid_t pid, struct ibuf *buf)
289 {
290 	struct ibuf	*hdrbuf = NULL;
291 	struct imsg_hdr	 hdr;
292 	int save_errno;
293 
294 	if (ibuf_size(buf) + IMSG_HEADER_SIZE > MAX_IMSGSIZE) {
295 		errno = ERANGE;
296 		goto fail;
297 	}
298 
299 	hdr.type = type;
300 	hdr.len = ibuf_size(buf) + IMSG_HEADER_SIZE;
301 	hdr.flags = 0;
302 	hdr.peerid = id;
303 	if ((hdr.pid = pid) == 0)
304 		hdr.pid = imsgbuf->pid;
305 
306 	if ((hdrbuf = ibuf_open(IMSG_HEADER_SIZE)) == NULL)
307 		goto fail;
308 	if (imsg_add(hdrbuf, &hdr, sizeof(hdr)) == -1)
309 		goto fail;
310 
311 	ibuf_close(&imsgbuf->w, hdrbuf);
312 	ibuf_close(&imsgbuf->w, buf);
313 	return (1);
314 
315  fail:
316 	save_errno = errno;
317 	ibuf_free(buf);
318 	ibuf_free(hdrbuf);
319 	errno = save_errno;
320 	return (-1);
321 }
322 
323 /*
324  * Forward imsg to another channel. Any attached fd is closed.
325  */
326 int
327 imsg_forward(struct imsgbuf *imsgbuf, struct imsg *msg)
328 {
329 	struct ibuf	*wbuf;
330 	size_t		 len = 0;
331 
332 	if (msg->fd != -1) {
333 		close(msg->fd);
334 		msg->fd = -1;
335 	}
336 
337 	if (msg->buf != NULL) {
338 		ibuf_rewind(msg->buf);
339 		len = ibuf_size(msg->buf);
340 	}
341 
342 	if ((wbuf = imsg_create(imsgbuf, msg->hdr.type, msg->hdr.peerid,
343 	    msg->hdr.pid, len)) == NULL)
344 		return (-1);
345 
346 	if (msg->buf != NULL) {
347 		if (ibuf_add_buf(wbuf, msg->buf) == -1) {
348 			ibuf_free(wbuf);
349 			return (-1);
350 		}
351 	}
352 
353 	imsg_close(imsgbuf, wbuf);
354 	return (1);
355 }
356 
357 struct ibuf *
358 imsg_create(struct imsgbuf *imsgbuf, uint32_t type, uint32_t id, pid_t pid,
359     size_t datalen)
360 {
361 	struct ibuf	*wbuf;
362 	struct imsg_hdr	 hdr;
363 
364 	datalen += IMSG_HEADER_SIZE;
365 	if (datalen > MAX_IMSGSIZE) {
366 		errno = ERANGE;
367 		return (NULL);
368 	}
369 
370 	hdr.type = type;
371 	hdr.flags = 0;
372 	hdr.peerid = id;
373 	if ((hdr.pid = pid) == 0)
374 		hdr.pid = imsgbuf->pid;
375 	if ((wbuf = ibuf_dynamic(datalen, MAX_IMSGSIZE)) == NULL) {
376 		return (NULL);
377 	}
378 	if (imsg_add(wbuf, &hdr, sizeof(hdr)) == -1)
379 		return (NULL);
380 
381 	return (wbuf);
382 }
383 
384 int
385 imsg_add(struct ibuf *msg, const void *data, size_t datalen)
386 {
387 	if (datalen)
388 		if (ibuf_add(msg, data, datalen) == -1) {
389 			ibuf_free(msg);
390 			return (-1);
391 		}
392 	return (datalen);
393 }
394 
395 void
396 imsg_close(struct imsgbuf *imsgbuf, struct ibuf *msg)
397 {
398 	struct imsg_hdr	*hdr;
399 
400 	hdr = (struct imsg_hdr *)msg->buf;
401 
402 	hdr->flags &= ~IMSGF_HASFD;
403 	if (ibuf_fd_avail(msg))
404 		hdr->flags |= IMSGF_HASFD;
405 	hdr->len = ibuf_size(msg);
406 
407 	ibuf_close(&imsgbuf->w, msg);
408 }
409 
410 void
411 imsg_free(struct imsg *imsg)
412 {
413 	ibuf_free(imsg->buf);
414 }
415 
416 static int
417 imsg_dequeue_fd(struct imsgbuf *imsgbuf)
418 {
419 	int		 fd;
420 	struct imsg_fd	*ifd;
421 
422 	if ((ifd = TAILQ_FIRST(&imsgbuf->fds)) == NULL)
423 		return (-1);
424 
425 	fd = ifd->fd;
426 	TAILQ_REMOVE(&imsgbuf->fds, ifd, entry);
427 	free(ifd);
428 
429 	return (fd);
430 }
431 
432 int
433 imsg_flush(struct imsgbuf *imsgbuf)
434 {
435 	while (imsgbuf->w.queued)
436 		if (msgbuf_write(&imsgbuf->w) <= 0)
437 			return (-1);
438 	return (0);
439 }
440 
441 void
442 imsg_clear(struct imsgbuf *imsgbuf)
443 {
444 	int	fd;
445 
446 	msgbuf_clear(&imsgbuf->w);
447 	while ((fd = imsg_dequeue_fd(imsgbuf)) != -1)
448 		close(fd);
449 }