1 f6df3e85 2022-01-28 op /*	$OpenBSD: imsg.c,v 1.17 2022/01/28 10:41:44 claudio Exp $	*/
  2 bbcba3ed 2022-01-10 op 
  3 bbcba3ed 2022-01-10 op /*
  4 bbcba3ed 2022-01-10 op  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
  5 bbcba3ed 2022-01-10 op  *
  6 bbcba3ed 2022-01-10 op  * Permission to use, copy, modify, and distribute this software for any
  7 bbcba3ed 2022-01-10 op  * purpose with or without fee is hereby granted, provided that the above
  8 bbcba3ed 2022-01-10 op  * copyright notice and this permission notice appear in all copies.
  9 bbcba3ed 2022-01-10 op  *
 10 bbcba3ed 2022-01-10 op  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 11 bbcba3ed 2022-01-10 op  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 12 bbcba3ed 2022-01-10 op  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 13 bbcba3ed 2022-01-10 op  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 14 bbcba3ed 2022-01-10 op  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 15 bbcba3ed 2022-01-10 op  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 16 bbcba3ed 2022-01-10 op  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 17 bbcba3ed 2022-01-10 op  */
 18 bbcba3ed 2022-01-10 op 
 19 bbcba3ed 2022-01-10 op #include "compat.h"
 20 bbcba3ed 2022-01-10 op 
 21 bbcba3ed 2022-01-10 op #include <sys/types.h>
 22 bbcba3ed 2022-01-10 op #include <sys/socket.h>
 23 bbcba3ed 2022-01-10 op #include <sys/uio.h>
 24 bbcba3ed 2022-01-10 op 
 25 bbcba3ed 2022-01-10 op #include <errno.h>
 26 bbcba3ed 2022-01-10 op #include <stdlib.h>
 27 bbcba3ed 2022-01-10 op #include <string.h>
 28 bbcba3ed 2022-01-10 op #include <unistd.h>
 29 bbcba3ed 2022-01-10 op 
 30 bbcba3ed 2022-01-10 op #include "imsg.h"
 31 bbcba3ed 2022-01-10 op 
 32 bbcba3ed 2022-01-10 op int	 imsg_fd_overhead = 0;
 33 bbcba3ed 2022-01-10 op 
 34 bbcba3ed 2022-01-10 op static int	 imsg_get_fd(struct imsgbuf *);
 35 bbcba3ed 2022-01-10 op 
 36 bbcba3ed 2022-01-10 op void
 37 bbcba3ed 2022-01-10 op imsg_init(struct imsgbuf *ibuf, int fd)
 38 bbcba3ed 2022-01-10 op {
 39 bbcba3ed 2022-01-10 op 	msgbuf_init(&ibuf->w);
 40 bbcba3ed 2022-01-10 op 	memset(&ibuf->r, 0, sizeof(ibuf->r));
 41 bbcba3ed 2022-01-10 op 	ibuf->fd = fd;
 42 bbcba3ed 2022-01-10 op 	ibuf->w.fd = fd;
 43 bbcba3ed 2022-01-10 op 	ibuf->pid = getpid();
 44 bbcba3ed 2022-01-10 op 	TAILQ_INIT(&ibuf->fds);
 45 bbcba3ed 2022-01-10 op }
 46 bbcba3ed 2022-01-10 op 
 47 bbcba3ed 2022-01-10 op ssize_t
 48 bbcba3ed 2022-01-10 op imsg_read(struct imsgbuf *ibuf)
 49 bbcba3ed 2022-01-10 op {
 50 bbcba3ed 2022-01-10 op 	struct msghdr		 msg;
 51 bbcba3ed 2022-01-10 op 	struct cmsghdr		*cmsg;
 52 bbcba3ed 2022-01-10 op 	union {
 53 bbcba3ed 2022-01-10 op 		struct cmsghdr hdr;
 54 bbcba3ed 2022-01-10 op 		char	buf[CMSG_SPACE(sizeof(int) * 1)];
 55 bbcba3ed 2022-01-10 op 	} cmsgbuf;
 56 bbcba3ed 2022-01-10 op 	struct iovec		 iov;
 57 bbcba3ed 2022-01-10 op 	ssize_t			 n = -1;
 58 bbcba3ed 2022-01-10 op 	int			 fd;
 59 bbcba3ed 2022-01-10 op 	struct imsg_fd		*ifd;
 60 bbcba3ed 2022-01-10 op 
 61 bbcba3ed 2022-01-10 op 	memset(&msg, 0, sizeof(msg));
 62 bbcba3ed 2022-01-10 op 	memset(&cmsgbuf, 0, sizeof(cmsgbuf));
 63 bbcba3ed 2022-01-10 op 
 64 bbcba3ed 2022-01-10 op 	iov.iov_base = ibuf->r.buf + ibuf->r.wpos;
 65 bbcba3ed 2022-01-10 op 	iov.iov_len = sizeof(ibuf->r.buf) - ibuf->r.wpos;
 66 bbcba3ed 2022-01-10 op 	msg.msg_iov = &iov;
 67 bbcba3ed 2022-01-10 op 	msg.msg_iovlen = 1;
 68 bbcba3ed 2022-01-10 op 	msg.msg_control = &cmsgbuf.buf;
 69 bbcba3ed 2022-01-10 op 	msg.msg_controllen = sizeof(cmsgbuf.buf);
 70 bbcba3ed 2022-01-10 op 
 71 bbcba3ed 2022-01-10 op 	if ((ifd = calloc(1, sizeof(struct imsg_fd))) == NULL)
 72 bbcba3ed 2022-01-10 op 		return (-1);
 73 bbcba3ed 2022-01-10 op 
 74 bbcba3ed 2022-01-10 op again:
 75 bbcba3ed 2022-01-10 op 	if (getdtablecount() + imsg_fd_overhead +
 76 bbcba3ed 2022-01-10 op 	    (int)((CMSG_SPACE(sizeof(int))-CMSG_SPACE(0))/sizeof(int))
 77 bbcba3ed 2022-01-10 op 	    >= getdtablesize()) {
 78 bbcba3ed 2022-01-10 op 		errno = EAGAIN;
 79 bbcba3ed 2022-01-10 op 		free(ifd);
 80 bbcba3ed 2022-01-10 op 		return (-1);
 81 bbcba3ed 2022-01-10 op 	}
 82 bbcba3ed 2022-01-10 op 
 83 bbcba3ed 2022-01-10 op 	if ((n = recvmsg(ibuf->fd, &msg, 0)) == -1) {
 84 bbcba3ed 2022-01-10 op 		if (errno == EINTR)
 85 bbcba3ed 2022-01-10 op 			goto again;
 86 bbcba3ed 2022-01-10 op 		goto fail;
 87 bbcba3ed 2022-01-10 op 	}
 88 bbcba3ed 2022-01-10 op 
 89 bbcba3ed 2022-01-10 op 	ibuf->r.wpos += n;
 90 bbcba3ed 2022-01-10 op 
 91 bbcba3ed 2022-01-10 op 	for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL;
 92 bbcba3ed 2022-01-10 op 	    cmsg = CMSG_NXTHDR(&msg, cmsg)) {
 93 bbcba3ed 2022-01-10 op 		if (cmsg->cmsg_level == SOL_SOCKET &&
 94 bbcba3ed 2022-01-10 op 		    cmsg->cmsg_type == SCM_RIGHTS) {
 95 bbcba3ed 2022-01-10 op 			int i;
 96 bbcba3ed 2022-01-10 op 			int j;
 97 bbcba3ed 2022-01-10 op 
 98 bbcba3ed 2022-01-10 op 			/*
 99 bbcba3ed 2022-01-10 op 			 * We only accept one file descriptor.  Due to C
100 bbcba3ed 2022-01-10 op 			 * padding rules, our control buffer might contain
101 bbcba3ed 2022-01-10 op 			 * more than one fd, and we must close them.
102 bbcba3ed 2022-01-10 op 			 */
103 bbcba3ed 2022-01-10 op 			j = ((char *)cmsg + cmsg->cmsg_len -
104 bbcba3ed 2022-01-10 op 			    (char *)CMSG_DATA(cmsg)) / sizeof(int);
105 bbcba3ed 2022-01-10 op 			for (i = 0; i < j; i++) {
106 bbcba3ed 2022-01-10 op 				fd = ((int *)CMSG_DATA(cmsg))[i];
107 bbcba3ed 2022-01-10 op 				if (ifd != NULL) {
108 bbcba3ed 2022-01-10 op 					ifd->fd = fd;
109 bbcba3ed 2022-01-10 op 					TAILQ_INSERT_TAIL(&ibuf->fds, ifd,
110 bbcba3ed 2022-01-10 op 					    entry);
111 bbcba3ed 2022-01-10 op 					ifd = NULL;
112 bbcba3ed 2022-01-10 op 				} else
113 bbcba3ed 2022-01-10 op 					close(fd);
114 bbcba3ed 2022-01-10 op 			}
115 bbcba3ed 2022-01-10 op 		}
116 bbcba3ed 2022-01-10 op 		/* we do not handle other ctl data level */
117 bbcba3ed 2022-01-10 op 	}
118 bbcba3ed 2022-01-10 op 
119 bbcba3ed 2022-01-10 op fail:
120 bbcba3ed 2022-01-10 op 	free(ifd);
121 bbcba3ed 2022-01-10 op 	return (n);
122 bbcba3ed 2022-01-10 op }
123 bbcba3ed 2022-01-10 op 
124 bbcba3ed 2022-01-10 op ssize_t
125 bbcba3ed 2022-01-10 op imsg_get(struct imsgbuf *ibuf, struct imsg *imsg)
126 bbcba3ed 2022-01-10 op {
127 bbcba3ed 2022-01-10 op 	size_t			 av, left, datalen;
128 bbcba3ed 2022-01-10 op 
129 bbcba3ed 2022-01-10 op 	av = ibuf->r.wpos;
130 bbcba3ed 2022-01-10 op 
131 bbcba3ed 2022-01-10 op 	if (IMSG_HEADER_SIZE > av)
132 bbcba3ed 2022-01-10 op 		return (0);
133 bbcba3ed 2022-01-10 op 
134 bbcba3ed 2022-01-10 op 	memcpy(&imsg->hdr, ibuf->r.buf, sizeof(imsg->hdr));
135 bbcba3ed 2022-01-10 op 	if (imsg->hdr.len < IMSG_HEADER_SIZE ||
136 bbcba3ed 2022-01-10 op 	    imsg->hdr.len > MAX_IMSGSIZE) {
137 bbcba3ed 2022-01-10 op 		errno = ERANGE;
138 bbcba3ed 2022-01-10 op 		return (-1);
139 bbcba3ed 2022-01-10 op 	}
140 bbcba3ed 2022-01-10 op 	if (imsg->hdr.len > av)
141 bbcba3ed 2022-01-10 op 		return (0);
142 bbcba3ed 2022-01-10 op 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
143 bbcba3ed 2022-01-10 op 	ibuf->r.rptr = ibuf->r.buf + IMSG_HEADER_SIZE;
144 bbcba3ed 2022-01-10 op 	if (datalen == 0)
145 bbcba3ed 2022-01-10 op 		imsg->data = NULL;
146 bbcba3ed 2022-01-10 op 	else if ((imsg->data = malloc(datalen)) == NULL)
147 bbcba3ed 2022-01-10 op 		return (-1);
148 bbcba3ed 2022-01-10 op 
149 bbcba3ed 2022-01-10 op 	if (imsg->hdr.flags & IMSGF_HASFD)
150 bbcba3ed 2022-01-10 op 		imsg->fd = imsg_get_fd(ibuf);
151 bbcba3ed 2022-01-10 op 	else
152 bbcba3ed 2022-01-10 op 		imsg->fd = -1;
153 bbcba3ed 2022-01-10 op 
154 f6df3e85 2022-01-28 op 	if (datalen != 0)
155 f6df3e85 2022-01-28 op 		memcpy(imsg->data, ibuf->r.rptr, datalen);
156 bbcba3ed 2022-01-10 op 
157 bbcba3ed 2022-01-10 op 	if (imsg->hdr.len < av) {
158 bbcba3ed 2022-01-10 op 		left = av - imsg->hdr.len;
159 bbcba3ed 2022-01-10 op 		memmove(&ibuf->r.buf, ibuf->r.buf + imsg->hdr.len, left);
160 bbcba3ed 2022-01-10 op 		ibuf->r.wpos = left;
161 bbcba3ed 2022-01-10 op 	} else
162 bbcba3ed 2022-01-10 op 		ibuf->r.wpos = 0;
163 bbcba3ed 2022-01-10 op 
164 bbcba3ed 2022-01-10 op 	return (datalen + IMSG_HEADER_SIZE);
165 bbcba3ed 2022-01-10 op }
166 bbcba3ed 2022-01-10 op 
167 bbcba3ed 2022-01-10 op int
168 bbcba3ed 2022-01-10 op imsg_compose(struct imsgbuf *ibuf, uint32_t type, uint32_t peerid, pid_t pid,
169 bbcba3ed 2022-01-10 op     int fd, const void *data, uint16_t datalen)
170 bbcba3ed 2022-01-10 op {
171 bbcba3ed 2022-01-10 op 	struct ibuf	*wbuf;
172 bbcba3ed 2022-01-10 op 
173 bbcba3ed 2022-01-10 op 	if ((wbuf = imsg_create(ibuf, type, peerid, pid, datalen)) == NULL)
174 bbcba3ed 2022-01-10 op 		return (-1);
175 bbcba3ed 2022-01-10 op 
176 bbcba3ed 2022-01-10 op 	if (imsg_add(wbuf, data, datalen) == -1)
177 bbcba3ed 2022-01-10 op 		return (-1);
178 bbcba3ed 2022-01-10 op 
179 bbcba3ed 2022-01-10 op 	wbuf->fd = fd;
180 bbcba3ed 2022-01-10 op 
181 bbcba3ed 2022-01-10 op 	imsg_close(ibuf, wbuf);
182 bbcba3ed 2022-01-10 op 
183 bbcba3ed 2022-01-10 op 	return (1);
184 bbcba3ed 2022-01-10 op }
185 bbcba3ed 2022-01-10 op 
186 bbcba3ed 2022-01-10 op int
187 bbcba3ed 2022-01-10 op imsg_composev(struct imsgbuf *ibuf, uint32_t type, uint32_t peerid, pid_t pid,
188 bbcba3ed 2022-01-10 op     int fd, const struct iovec *iov, int iovcnt)
189 bbcba3ed 2022-01-10 op {
190 bbcba3ed 2022-01-10 op 	struct ibuf	*wbuf;
191 bbcba3ed 2022-01-10 op 	int		 i, datalen = 0;
192 bbcba3ed 2022-01-10 op 
193 bbcba3ed 2022-01-10 op 	for (i = 0; i < iovcnt; i++)
194 bbcba3ed 2022-01-10 op 		datalen += iov[i].iov_len;
195 bbcba3ed 2022-01-10 op 
196 bbcba3ed 2022-01-10 op 	if ((wbuf = imsg_create(ibuf, type, peerid, pid, datalen)) == NULL)
197 bbcba3ed 2022-01-10 op 		return (-1);
198 bbcba3ed 2022-01-10 op 
199 bbcba3ed 2022-01-10 op 	for (i = 0; i < iovcnt; i++)
200 bbcba3ed 2022-01-10 op 		if (imsg_add(wbuf, iov[i].iov_base, iov[i].iov_len) == -1)
201 bbcba3ed 2022-01-10 op 			return (-1);
202 bbcba3ed 2022-01-10 op 
203 bbcba3ed 2022-01-10 op 	wbuf->fd = fd;
204 bbcba3ed 2022-01-10 op 
205 bbcba3ed 2022-01-10 op 	imsg_close(ibuf, wbuf);
206 bbcba3ed 2022-01-10 op 
207 bbcba3ed 2022-01-10 op 	return (1);
208 bbcba3ed 2022-01-10 op }
209 bbcba3ed 2022-01-10 op 
210 bbcba3ed 2022-01-10 op /* ARGSUSED */
211 bbcba3ed 2022-01-10 op struct ibuf *
212 bbcba3ed 2022-01-10 op imsg_create(struct imsgbuf *ibuf, uint32_t type, uint32_t peerid, pid_t pid,
213 bbcba3ed 2022-01-10 op     uint16_t datalen)
214 bbcba3ed 2022-01-10 op {
215 bbcba3ed 2022-01-10 op 	struct ibuf	*wbuf;
216 bbcba3ed 2022-01-10 op 	struct imsg_hdr	 hdr;
217 bbcba3ed 2022-01-10 op 
218 bbcba3ed 2022-01-10 op 	datalen += IMSG_HEADER_SIZE;
219 bbcba3ed 2022-01-10 op 	if (datalen > MAX_IMSGSIZE) {
220 bbcba3ed 2022-01-10 op 		errno = ERANGE;
221 bbcba3ed 2022-01-10 op 		return (NULL);
222 bbcba3ed 2022-01-10 op 	}
223 bbcba3ed 2022-01-10 op 
224 bbcba3ed 2022-01-10 op 	hdr.type = type;
225 bbcba3ed 2022-01-10 op 	hdr.flags = 0;
226 bbcba3ed 2022-01-10 op 	hdr.peerid = peerid;
227 bbcba3ed 2022-01-10 op 	if ((hdr.pid = pid) == 0)
228 bbcba3ed 2022-01-10 op 		hdr.pid = ibuf->pid;
229 bbcba3ed 2022-01-10 op 	if ((wbuf = ibuf_dynamic(datalen, MAX_IMSGSIZE)) == NULL) {
230 bbcba3ed 2022-01-10 op 		return (NULL);
231 bbcba3ed 2022-01-10 op 	}
232 bbcba3ed 2022-01-10 op 	if (imsg_add(wbuf, &hdr, sizeof(hdr)) == -1)
233 bbcba3ed 2022-01-10 op 		return (NULL);
234 bbcba3ed 2022-01-10 op 
235 bbcba3ed 2022-01-10 op 	return (wbuf);
236 bbcba3ed 2022-01-10 op }
237 bbcba3ed 2022-01-10 op 
238 bbcba3ed 2022-01-10 op int
239 bbcba3ed 2022-01-10 op imsg_add(struct ibuf *msg, const void *data, uint16_t datalen)
240 bbcba3ed 2022-01-10 op {
241 bbcba3ed 2022-01-10 op 	if (datalen)
242 bbcba3ed 2022-01-10 op 		if (ibuf_add(msg, data, datalen) == -1) {
243 bbcba3ed 2022-01-10 op 			ibuf_free(msg);
244 bbcba3ed 2022-01-10 op 			return (-1);
245 bbcba3ed 2022-01-10 op 		}
246 bbcba3ed 2022-01-10 op 	return (datalen);
247 bbcba3ed 2022-01-10 op }
248 bbcba3ed 2022-01-10 op 
249 bbcba3ed 2022-01-10 op void
250 bbcba3ed 2022-01-10 op imsg_close(struct imsgbuf *ibuf, struct ibuf *msg)
251 bbcba3ed 2022-01-10 op {
252 bbcba3ed 2022-01-10 op 	struct imsg_hdr	*hdr;
253 bbcba3ed 2022-01-10 op 
254 bbcba3ed 2022-01-10 op 	hdr = (struct imsg_hdr *)msg->buf;
255 bbcba3ed 2022-01-10 op 
256 bbcba3ed 2022-01-10 op 	hdr->flags &= ~IMSGF_HASFD;
257 bbcba3ed 2022-01-10 op 	if (msg->fd != -1)
258 bbcba3ed 2022-01-10 op 		hdr->flags |= IMSGF_HASFD;
259 bbcba3ed 2022-01-10 op 
260 bbcba3ed 2022-01-10 op 	hdr->len = (uint16_t)msg->wpos;
261 bbcba3ed 2022-01-10 op 
262 bbcba3ed 2022-01-10 op 	ibuf_close(&ibuf->w, msg);
263 bbcba3ed 2022-01-10 op }
264 bbcba3ed 2022-01-10 op 
265 bbcba3ed 2022-01-10 op void
266 bbcba3ed 2022-01-10 op imsg_free(struct imsg *imsg)
267 bbcba3ed 2022-01-10 op {
268 bbcba3ed 2022-01-10 op 	freezero(imsg->data, imsg->hdr.len - IMSG_HEADER_SIZE);
269 bbcba3ed 2022-01-10 op }
270 bbcba3ed 2022-01-10 op 
271 bbcba3ed 2022-01-10 op static int
272 bbcba3ed 2022-01-10 op imsg_get_fd(struct imsgbuf *ibuf)
273 bbcba3ed 2022-01-10 op {
274 bbcba3ed 2022-01-10 op 	int		 fd;
275 bbcba3ed 2022-01-10 op 	struct imsg_fd	*ifd;
276 bbcba3ed 2022-01-10 op 
277 bbcba3ed 2022-01-10 op 	if ((ifd = TAILQ_FIRST(&ibuf->fds)) == NULL)
278 bbcba3ed 2022-01-10 op 		return (-1);
279 bbcba3ed 2022-01-10 op 
280 bbcba3ed 2022-01-10 op 	fd = ifd->fd;
281 bbcba3ed 2022-01-10 op 	TAILQ_REMOVE(&ibuf->fds, ifd, entry);
282 bbcba3ed 2022-01-10 op 	free(ifd);
283 bbcba3ed 2022-01-10 op 
284 bbcba3ed 2022-01-10 op 	return (fd);
285 bbcba3ed 2022-01-10 op }
286 bbcba3ed 2022-01-10 op 
287 bbcba3ed 2022-01-10 op int
288 bbcba3ed 2022-01-10 op imsg_flush(struct imsgbuf *ibuf)
289 bbcba3ed 2022-01-10 op {
290 bbcba3ed 2022-01-10 op 	while (ibuf->w.queued)
291 bbcba3ed 2022-01-10 op 		if (msgbuf_write(&ibuf->w) <= 0)
292 bbcba3ed 2022-01-10 op 			return (-1);
293 bbcba3ed 2022-01-10 op 	return (0);
294 bbcba3ed 2022-01-10 op }
295 bbcba3ed 2022-01-10 op 
296 bbcba3ed 2022-01-10 op void
297 bbcba3ed 2022-01-10 op imsg_clear(struct imsgbuf *ibuf)
298 bbcba3ed 2022-01-10 op {
299 bbcba3ed 2022-01-10 op 	int	fd;
300 bbcba3ed 2022-01-10 op 
301 bbcba3ed 2022-01-10 op 	msgbuf_clear(&ibuf->w);
302 bbcba3ed 2022-01-10 op 	while ((fd = imsg_get_fd(ibuf)) != -1)
303 bbcba3ed 2022-01-10 op 		close(fd);
304 bbcba3ed 2022-01-10 op }