1 /* $OpenBSD: imsg.c,v 1.23 2023/12/12 15:47:41 claudio Exp $ */
4 * Copyright (c) 2023 Claudio Jeker <claudio@openbsd.org>
5 * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
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.
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.
22 #include <sys/types.h>
23 #include <sys/socket.h>
34 TAILQ_ENTRY(imsg_fd) entry;
38 int imsg_fd_overhead = 0;
40 static int imsg_dequeue_fd(struct imsgbuf *);
43 imsg_init(struct imsgbuf *imsgbuf, int fd)
45 msgbuf_init(&imsgbuf->w);
46 memset(&imsgbuf->r, 0, sizeof(imsgbuf->r));
49 imsgbuf->pid = getpid();
50 TAILQ_INIT(&imsgbuf->fds);
54 imsg_read(struct imsgbuf *imsgbuf)
60 char buf[CMSG_SPACE(sizeof(int) * 1)];
67 memset(&msg, 0, sizeof(msg));
68 memset(&cmsgbuf, 0, sizeof(cmsgbuf));
70 iov.iov_base = imsgbuf->r.buf + imsgbuf->r.wpos;
71 iov.iov_len = sizeof(imsgbuf->r.buf) - imsgbuf->r.wpos;
74 msg.msg_control = &cmsgbuf.buf;
75 msg.msg_controllen = sizeof(cmsgbuf.buf);
77 if ((ifd = calloc(1, sizeof(struct imsg_fd))) == NULL)
81 if (getdtablecount() + imsg_fd_overhead +
82 (int)((CMSG_SPACE(sizeof(int))-CMSG_SPACE(0))/sizeof(int))
89 if ((n = recvmsg(imsgbuf->fd, &msg, 0)) == -1) {
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) {
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.
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];
115 TAILQ_INSERT_TAIL(&imsgbuf->fds, ifd,
122 /* we do not handle other ctl data level */
131 imsg_get(struct imsgbuf *imsgbuf, struct imsg *imsg)
134 size_t av, left, datalen;
136 av = imsgbuf->r.wpos;
138 if (IMSG_HEADER_SIZE > av)
141 memcpy(&m.hdr, imsgbuf->r.buf, sizeof(m.hdr));
142 if (m.hdr.len < IMSG_HEADER_SIZE ||
143 m.hdr.len > MAX_IMSGSIZE) {
154 datalen = m.hdr.len - IMSG_HEADER_SIZE;
155 imsgbuf->r.rptr = imsgbuf->r.buf + IMSG_HEADER_SIZE;
157 if ((m.buf = ibuf_open(datalen)) == NULL)
159 if (ibuf_add(m.buf, imsgbuf->r.rptr, datalen) == -1) {
160 /* this should never fail */
164 m.data = ibuf_data(m.buf);
167 if (m.hdr.flags & IMSGF_HASFD)
168 m.fd = imsg_dequeue_fd(imsgbuf);
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;
178 return (datalen + IMSG_HEADER_SIZE);
182 imsg_get_ibuf(struct imsg *imsg, struct ibuf *ibuf)
184 if (imsg->buf == NULL) {
188 return ibuf_get_ibuf(imsg->buf, ibuf_size(imsg->buf), ibuf);
192 imsg_get_data(struct imsg *imsg, void *data, size_t len)
198 if (imsg->buf == NULL || ibuf_size(imsg->buf) != len) {
202 return ibuf_get(imsg->buf, data, len);
206 imsg_get_fd(struct imsg *imsg)
215 imsg_get_id(struct imsg *imsg)
217 return (imsg->hdr.peerid);
221 imsg_get_len(struct imsg *imsg)
223 if (imsg->buf == NULL)
225 return ibuf_size(imsg->buf);
229 imsg_get_pid(struct imsg *imsg)
231 return (imsg->hdr.pid);
235 imsg_get_type(struct imsg *imsg)
237 return (imsg->hdr.type);
241 imsg_compose(struct imsgbuf *imsgbuf, uint32_t type, uint32_t id, pid_t pid,
242 int fd, const void *data, size_t datalen)
246 if ((wbuf = imsg_create(imsgbuf, type, id, pid, datalen)) == NULL)
249 if (imsg_add(wbuf, data, datalen) == -1)
252 ibuf_fd_set(wbuf, fd);
253 imsg_close(imsgbuf, wbuf);
259 imsg_composev(struct imsgbuf *imsgbuf, uint32_t type, uint32_t id, pid_t pid,
260 int fd, const struct iovec *iov, int iovcnt)
266 for (i = 0; i < iovcnt; i++)
267 datalen += iov[i].iov_len;
269 if ((wbuf = imsg_create(imsgbuf, type, id, pid, datalen)) == NULL)
272 for (i = 0; i < iovcnt; i++)
273 if (imsg_add(wbuf, iov[i].iov_base, iov[i].iov_len) == -1)
276 ibuf_fd_set(wbuf, fd);
277 imsg_close(imsgbuf, wbuf);
283 * Enqueue imsg with payload from ibuf buf. fd passing is not possible
284 * with this function.
287 imsg_compose_ibuf(struct imsgbuf *imsgbuf, uint32_t type, uint32_t id,
288 pid_t pid, struct ibuf *buf)
290 struct ibuf *hdrbuf = NULL;
294 if (ibuf_size(buf) + IMSG_HEADER_SIZE > MAX_IMSGSIZE) {
300 hdr.len = ibuf_size(buf) + IMSG_HEADER_SIZE;
303 if ((hdr.pid = pid) == 0)
304 hdr.pid = imsgbuf->pid;
306 if ((hdrbuf = ibuf_open(IMSG_HEADER_SIZE)) == NULL)
308 if (imsg_add(hdrbuf, &hdr, sizeof(hdr)) == -1)
311 ibuf_close(&imsgbuf->w, hdrbuf);
312 ibuf_close(&imsgbuf->w, buf);
324 * Forward imsg to another channel. Any attached fd is closed.
327 imsg_forward(struct imsgbuf *imsgbuf, struct imsg *msg)
337 if (msg->buf != NULL) {
338 ibuf_rewind(msg->buf);
339 len = ibuf_size(msg->buf);
342 if ((wbuf = imsg_create(imsgbuf, msg->hdr.type, msg->hdr.peerid,
343 msg->hdr.pid, len)) == NULL)
346 if (msg->buf != NULL) {
347 if (ibuf_add_buf(wbuf, msg->buf) == -1) {
353 imsg_close(imsgbuf, wbuf);
358 imsg_create(struct imsgbuf *imsgbuf, uint32_t type, uint32_t id, pid_t pid,
364 datalen += IMSG_HEADER_SIZE;
365 if (datalen > MAX_IMSGSIZE) {
373 if ((hdr.pid = pid) == 0)
374 hdr.pid = imsgbuf->pid;
375 if ((wbuf = ibuf_dynamic(datalen, MAX_IMSGSIZE)) == NULL) {
378 if (imsg_add(wbuf, &hdr, sizeof(hdr)) == -1)
385 imsg_add(struct ibuf *msg, const void *data, size_t datalen)
388 if (ibuf_add(msg, data, datalen) == -1) {
396 imsg_close(struct imsgbuf *imsgbuf, struct ibuf *msg)
398 struct imsg_hdr *hdr;
400 hdr = (struct imsg_hdr *)msg->buf;
402 hdr->flags &= ~IMSGF_HASFD;
403 if (ibuf_fd_avail(msg))
404 hdr->flags |= IMSGF_HASFD;
405 hdr->len = ibuf_size(msg);
407 ibuf_close(&imsgbuf->w, msg);
411 imsg_free(struct imsg *imsg)
413 ibuf_free(imsg->buf);
417 imsg_dequeue_fd(struct imsgbuf *imsgbuf)
422 if ((ifd = TAILQ_FIRST(&imsgbuf->fds)) == NULL)
426 TAILQ_REMOVE(&imsgbuf->fds, ifd, entry);
433 imsg_flush(struct imsgbuf *imsgbuf)
435 while (imsgbuf->w.queued)
436 if (msgbuf_write(&imsgbuf->w) <= 0)
442 imsg_clear(struct imsgbuf *imsgbuf)
446 msgbuf_clear(&imsgbuf->w);
447 while ((fd = imsg_dequeue_fd(imsgbuf)) != -1)