[mirror_frr.git] / lib / imsg.c

/*	$OpenBSD$	*/

/*
 * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <zebra.h>

#include "queue.h"
#include "imsg.h"

int imsg_fd_overhead = 0;

int imsg_get_fd(struct imsgbuf *);

#ifndef __OpenBSD__
/*
 * The original code calls getdtablecount() which is OpenBSD specific. Use
 * available_fds() from OpenSMTPD instead.
 */
static int available_fds(unsigned int n)
{
	unsigned int i;
	int ret, fds[256];

	if (n > (sizeof(fds) / sizeof(fds[0])))
		return (1);

	ret = 0;
	for (i = 0; i < n; i++) {
		fds[i] = -1;
		if ((fds[i] = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
			if (errno == EAFNOSUPPORT || errno == EPROTONOSUPPORT)
				fds[i] = socket(AF_INET6, SOCK_DGRAM, 0);
			if (fds[i] < 0) {
				ret = 1;
				break;
			}
		}
	}

	for (i = 0; i < n && fds[i] >= 0; i++)
		close(fds[i]);

	return (ret);
}
#endif

void imsg_init(struct imsgbuf *ibuf, int fd)
{
	msgbuf_init(&ibuf->w);
	memset(&ibuf->r, 0, sizeof(ibuf->r));
	ibuf->fd = fd;
	ibuf->w.fd = fd;
	ibuf->pid = getpid();
	TAILQ_INIT(&ibuf->fds);
}

ssize_t imsg_read(struct imsgbuf *ibuf)
{
	struct msghdr msg;
	struct cmsghdr *cmsg;
	union {
		struct cmsghdr hdr;
		char buf[CMSG_SPACE(sizeof(int) * 1)];
	} cmsgbuf;
	struct iovec iov;
	ssize_t n = -1;
	int fd;
	struct imsg_fd *ifd;

	memset(&msg, 0, sizeof(msg));
	memset(&cmsgbuf, 0, sizeof(cmsgbuf));

	iov.iov_base = ibuf->r.buf + ibuf->r.wpos;
	iov.iov_len = sizeof(ibuf->r.buf) - ibuf->r.wpos;
	msg.msg_iov = &iov;
	msg.msg_iovlen = 1;
	msg.msg_control = &cmsgbuf.buf;
	msg.msg_controllen = sizeof(cmsgbuf.buf);

	if ((ifd = calloc(1, sizeof(struct imsg_fd))) == NULL)
		return (-1);

again:
#ifdef __OpenBSD__
	if (getdtablecount() + imsg_fd_overhead
		    + (int)((CMSG_SPACE(sizeof(int)) - CMSG_SPACE(0))
			    / sizeof(int))
	    >= getdtablesize()) {
#else
	if (available_fds(imsg_fd_overhead
			  + (CMSG_SPACE(sizeof(int)) - CMSG_SPACE(0))
				    / sizeof(int))) {
#endif
		errno = EAGAIN;
		free(ifd);
		return (-1);
	}

	if ((n = recvmsg(ibuf->fd, &msg, 0)) == -1) {
		if (errno == EINTR)
			goto again;
		goto fail;
	}

	ibuf->r.wpos += n;

	for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL;
	     cmsg = CMSG_NXTHDR(&msg, cmsg)) {
		if (cmsg->cmsg_level == SOL_SOCKET
		    && cmsg->cmsg_type == SCM_RIGHTS) {
			int i;
			int j;

			/*
			 * We only accept one file descriptor.  Due to C
			 * padding rules, our control buffer might contain
			 * more than one fd, and we must close them.
			 */
			j = ((char *)cmsg + cmsg->cmsg_len
			     - (char *)CMSG_DATA(cmsg))
			    / sizeof(int);
			for (i = 0; i < j; i++) {
				fd = ((int *)CMSG_DATA(cmsg))[i];
				if (ifd != NULL) {
					ifd->fd = fd;
					TAILQ_INSERT_TAIL(&ibuf->fds, ifd,
							  entry);
					ifd = NULL;
				} else
					close(fd);
			}
		}
		/* we do not handle other ctl data level */
	}

fail:
	free(ifd);
	return (n);
}

ssize_t imsg_get(struct imsgbuf *ibuf, struct imsg *imsg)
{
	size_t av, left, datalen;

	av = ibuf->r.wpos;

	if (IMSG_HEADER_SIZE > av)
		return (0);

	memcpy(&imsg->hdr, ibuf->r.buf, sizeof(imsg->hdr));
	if (imsg->hdr.len < IMSG_HEADER_SIZE || imsg->hdr.len > MAX_IMSGSIZE) {
		errno = ERANGE;
		return (-1);
	}
	if (imsg->hdr.len > av)
		return (0);
	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
	ibuf->r.rptr = ibuf->r.buf + IMSG_HEADER_SIZE;
	if (datalen == 0)
		imsg->data = NULL;
	else if ((imsg->data = malloc(datalen)) == NULL)
		return (-1);

	if (imsg->hdr.flags & IMSGF_HASFD)
		imsg->fd = imsg_get_fd(ibuf);
	else
		imsg->fd = -1;

	if (imsg->data)
		memcpy(imsg->data, ibuf->r.rptr, datalen);

	if (imsg->hdr.len < av) {
		left = av - imsg->hdr.len;
		memmove(&ibuf->r.buf, ibuf->r.buf + imsg->hdr.len, left);
		ibuf->r.wpos = left;
	} else
		ibuf->r.wpos = 0;

	return (datalen + IMSG_HEADER_SIZE);
}

int imsg_compose(struct imsgbuf *ibuf, u_int32_t type, u_int32_t peerid,
		 pid_t pid, int fd, const void *data, u_int16_t datalen)
{
	struct ibuf *wbuf;

	if ((wbuf = imsg_create(ibuf, type, peerid, pid, datalen)) == NULL)
		return (-1);

	if (imsg_add(wbuf, data, datalen) == -1)
		return (-1);

	wbuf->fd = fd;

	imsg_close(ibuf, wbuf);

	return (1);
}

int imsg_composev(struct imsgbuf *ibuf, u_int32_t type, u_int32_t peerid,
		  pid_t pid, int fd, const struct iovec *iov, int iovcnt)
{
	struct ibuf *wbuf;
	int i, datalen = 0;

	for (i = 0; i < iovcnt; i++)
		datalen += iov[i].iov_len;

	if ((wbuf = imsg_create(ibuf, type, peerid, pid, datalen)) == NULL)
		return (-1);

	for (i = 0; i < iovcnt; i++)
		if (imsg_add(wbuf, iov[i].iov_base, iov[i].iov_len) == -1)
			return (-1);

	wbuf->fd = fd;

	imsg_close(ibuf, wbuf);

	return (1);
}

/* ARGSUSED */
struct ibuf *imsg_create(struct imsgbuf *ibuf, u_int32_t type, u_int32_t peerid,
			 pid_t pid, u_int16_t datalen)
{
	struct ibuf *wbuf;
	struct imsg_hdr hdr;

	datalen += IMSG_HEADER_SIZE;
	if (datalen > MAX_IMSGSIZE) {
		errno = ERANGE;
		return (NULL);
	}

	hdr.type = type;
	hdr.flags = 0;
	hdr.peerid = peerid;
	if ((hdr.pid = pid) == 0)
		hdr.pid = ibuf->pid;
	if ((wbuf = ibuf_dynamic(datalen, MAX_IMSGSIZE)) == NULL) {
		return (NULL);
	}
	if (imsg_add(wbuf, &hdr, sizeof(hdr)) == -1)
		return (NULL);

	return (wbuf);
}

int imsg_add(struct ibuf *msg, const void *data, u_int16_t datalen)
{
	if (datalen)
		if (ibuf_add(msg, data, datalen) == -1) {
			ibuf_free(msg);
			return (-1);
		}
	return (datalen);
}

void imsg_close(struct imsgbuf *ibuf, struct ibuf *msg)
{
	struct imsg_hdr *hdr;

	hdr = (struct imsg_hdr *)msg->buf;

	hdr->flags &= ~IMSGF_HASFD;
	if (msg->fd != -1)
		hdr->flags |= IMSGF_HASFD;

	hdr->len = (u_int16_t)msg->wpos;

	ibuf_close(&ibuf->w, msg);
}

void imsg_free(struct imsg *imsg)
{
	free(imsg->data);
}

int imsg_get_fd(struct imsgbuf *ibuf)
{
	int fd;
	struct imsg_fd *ifd;

	if ((ifd = TAILQ_FIRST(&ibuf->fds)) == NULL)
		return (-1);

	fd = ifd->fd;
	TAILQ_REMOVE(&ibuf->fds, ifd, entry);
	free(ifd);

	return (fd);
}

int imsg_flush(struct imsgbuf *ibuf)
{
	while (ibuf->w.queued)
		if (msgbuf_write(&ibuf->w) <= 0)
			return (-1);
	return (0);
}

void imsg_clear(struct imsgbuf *ibuf)
{
	int fd;

	msgbuf_clear(&ibuf->w);
	while ((fd = imsg_get_fd(ibuf)) != -1)
		close(fd);
}
Commit	Line	Data
8429abe0 RW	1	/* $OpenBSD$ */
	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
eac6e3f0	19	#include <zebra.h>
8429abe0	20
cd85bc2e	21	#include "queue.h"
8429abe0 RW	22	#include "imsg.h"
8429abe0 RW	23
996c9314	24	int imsg_fd_overhead = 0;
8429abe0	25
996c9314	26	int imsg_get_fd(struct imsgbuf *);
8429abe0	27
eac6e3f0 RW	28	#ifndef __OpenBSD__
	29	/*
	30	* The original code calls getdtablecount() which is OpenBSD specific. Use
	31	* available_fds() from OpenSMTPD instead.
	32	*/
996c9314	33	static int available_fds(unsigned int n)
eac6e3f0	34	{
996c9314 LB	35	unsigned int i;
996c9314 LB	36	int ret, fds[256];
eac6e3f0	37
996c9314	38	if (n > (sizeof(fds) / sizeof(fds[0])))
eac6e3f0 RW	39	return (1);
	40
	41	ret = 0;
	42	for (i = 0; i < n; i++) {
	43	fds[i] = -1;
	44	if ((fds[i] = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
	45	if (errno == EAFNOSUPPORT \|\| errno == EPROTONOSUPPORT)
	46	fds[i] = socket(AF_INET6, SOCK_DGRAM, 0);
	47	if (fds[i] < 0) {
	48	ret = 1;
	49	break;
	50	}
	51	}
	52	}
	53
	54	for (i = 0; i < n && fds[i] >= 0; i++)
	55	close(fds[i]);
	56
	57	return (ret);
	58	}
	59	#endif
	60
996c9314	61	void imsg_init(struct imsgbuf *ibuf, int fd)
8429abe0 RW	62	{
	63	msgbuf_init(&ibuf->w);
	64	memset(&ibuf->r, 0, sizeof(ibuf->r));
	65	ibuf->fd = fd;
	66	ibuf->w.fd = fd;
	67	ibuf->pid = getpid();
	68	TAILQ_INIT(&ibuf->fds);
	69	}
	70
996c9314	71	ssize_t imsg_read(struct imsgbuf *ibuf)
8429abe0	72	{
996c9314 LB	73	struct msghdr msg;
996c9314 LB	74	struct cmsghdr *cmsg;
8429abe0 RW	75	union {
8429abe0 RW	76	struct cmsghdr hdr;
996c9314	77	char buf[CMSG_SPACE(sizeof(int) * 1)];
8429abe0	78	} cmsgbuf;
996c9314 LB	79	struct iovec iov;
	80	ssize_t n = -1;
	81	int fd;
	82	struct imsg_fd *ifd;
8429abe0 RW	83
	84	memset(&msg, 0, sizeof(msg));
	85	memset(&cmsgbuf, 0, sizeof(cmsgbuf));
	86
	87	iov.iov_base = ibuf->r.buf + ibuf->r.wpos;
	88	iov.iov_len = sizeof(ibuf->r.buf) - ibuf->r.wpos;
	89	msg.msg_iov = &iov;
	90	msg.msg_iovlen = 1;
	91	msg.msg_control = &cmsgbuf.buf;
	92	msg.msg_controllen = sizeof(cmsgbuf.buf);
	93
	94	if ((ifd = calloc(1, sizeof(struct imsg_fd))) == NULL)
	95	return (-1);
	96
	97	again:
eac6e3f0	98	#ifdef __OpenBSD__
996c9314 LB	99	if (getdtablecount() + imsg_fd_overhead
	100	+ (int)((CMSG_SPACE(sizeof(int)) - CMSG_SPACE(0))
	101	/ sizeof(int))
8429abe0	102	>= getdtablesize()) {
eac6e3f0	103	#else
996c9314 LB	104	if (available_fds(imsg_fd_overhead
	105	+ (CMSG_SPACE(sizeof(int)) - CMSG_SPACE(0))
	106	/ sizeof(int))) {
eac6e3f0	107	#endif
8429abe0 RW	108	errno = EAGAIN;
	109	free(ifd);
	110	return (-1);
	111	}
	112
	113	if ((n = recvmsg(ibuf->fd, &msg, 0)) == -1) {
	114	if (errno == EINTR)
	115	goto again;
	116	goto fail;
	117	}
	118
	119	ibuf->r.wpos += n;
	120
	121	for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL;
996c9314 LB	122	cmsg = CMSG_NXTHDR(&msg, cmsg)) {
	123	if (cmsg->cmsg_level == SOL_SOCKET
	124	&& cmsg->cmsg_type == SCM_RIGHTS) {
8429abe0 RW	125	int i;
	126	int j;
	127
	128	/*
	129	* We only accept one file descriptor. Due to C
	130	* padding rules, our control buffer might contain
	131	* more than one fd, and we must close them.
	132	*/
996c9314 LB	133	j = ((char *)cmsg + cmsg->cmsg_len
	134	- (char *)CMSG_DATA(cmsg))
	135	/ sizeof(int);
8429abe0 RW	136	for (i = 0; i < j; i++) {
	137	fd = ((int *)CMSG_DATA(cmsg))[i];
	138	if (ifd != NULL) {
	139	ifd->fd = fd;
	140	TAILQ_INSERT_TAIL(&ibuf->fds, ifd,
996c9314	141	entry);
8429abe0 RW	142	ifd = NULL;
	143	} else
	144	close(fd);
	145	}
	146	}
	147	/* we do not handle other ctl data level */
	148	}
	149
	150	fail:
	151	free(ifd);
	152	return (n);
	153	}
	154
996c9314	155	ssize_t imsg_get(struct imsgbuf ibuf, struct imsg imsg)
8429abe0	156	{
996c9314	157	size_t av, left, datalen;
8429abe0 RW	158
	159	av = ibuf->r.wpos;
	160
	161	if (IMSG_HEADER_SIZE > av)
	162	return (0);
	163
	164	memcpy(&imsg->hdr, ibuf->r.buf, sizeof(imsg->hdr));
996c9314	165	if (imsg->hdr.len < IMSG_HEADER_SIZE \|\| imsg->hdr.len > MAX_IMSGSIZE) {
8429abe0 RW	166	errno = ERANGE;
	167	return (-1);
	168	}
	169	if (imsg->hdr.len > av)
	170	return (0);
	171	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
	172	ibuf->r.rptr = ibuf->r.buf + IMSG_HEADER_SIZE;
	173	if (datalen == 0)
	174	imsg->data = NULL;
	175	else if ((imsg->data = malloc(datalen)) == NULL)
	176	return (-1);
	177
	178	if (imsg->hdr.flags & IMSGF_HASFD)
	179	imsg->fd = imsg_get_fd(ibuf);
	180	else
	181	imsg->fd = -1;
	182
dd3415b7	183	if (imsg->data)
996c9314	184	memcpy(imsg->data, ibuf->r.rptr, datalen);
8429abe0 RW	185
	186	if (imsg->hdr.len < av) {
	187	left = av - imsg->hdr.len;
	188	memmove(&ibuf->r.buf, ibuf->r.buf + imsg->hdr.len, left);
	189	ibuf->r.wpos = left;
	190	} else
	191	ibuf->r.wpos = 0;
	192
	193	return (datalen + IMSG_HEADER_SIZE);
	194	}
	195
996c9314 LB	196	int imsg_compose(struct imsgbuf *ibuf, u_int32_t type, u_int32_t peerid,
996c9314 LB	197	pid_t pid, int fd, const void *data, u_int16_t datalen)
8429abe0	198	{
996c9314	199	struct ibuf *wbuf;
8429abe0 RW	200
	201	if ((wbuf = imsg_create(ibuf, type, peerid, pid, datalen)) == NULL)
	202	return (-1);
	203
	204	if (imsg_add(wbuf, data, datalen) == -1)
	205	return (-1);
	206
	207	wbuf->fd = fd;
	208
	209	imsg_close(ibuf, wbuf);
	210
	211	return (1);
	212	}
	213
996c9314 LB	214	int imsg_composev(struct imsgbuf *ibuf, u_int32_t type, u_int32_t peerid,
996c9314 LB	215	pid_t pid, int fd, const struct iovec *iov, int iovcnt)
8429abe0	216	{
996c9314 LB	217	struct ibuf *wbuf;
996c9314 LB	218	int i, datalen = 0;
8429abe0 RW	219
	220	for (i = 0; i < iovcnt; i++)
	221	datalen += iov[i].iov_len;
	222
	223	if ((wbuf = imsg_create(ibuf, type, peerid, pid, datalen)) == NULL)
	224	return (-1);
	225
	226	for (i = 0; i < iovcnt; i++)
	227	if (imsg_add(wbuf, iov[i].iov_base, iov[i].iov_len) == -1)
	228	return (-1);
	229
	230	wbuf->fd = fd;
	231
	232	imsg_close(ibuf, wbuf);
	233
	234	return (1);
	235	}
	236
	237	/* ARGSUSED */
996c9314 LB	238	struct ibuf imsg_create(struct imsgbuf ibuf, u_int32_t type, u_int32_t peerid,
996c9314 LB	239	pid_t pid, u_int16_t datalen)
8429abe0	240	{
996c9314 LB	241	struct ibuf *wbuf;
996c9314 LB	242	struct imsg_hdr hdr;
8429abe0 RW	243
	244	datalen += IMSG_HEADER_SIZE;
	245	if (datalen > MAX_IMSGSIZE) {
	246	errno = ERANGE;
	247	return (NULL);
	248	}
	249
	250	hdr.type = type;
	251	hdr.flags = 0;
	252	hdr.peerid = peerid;
	253	if ((hdr.pid = pid) == 0)
	254	hdr.pid = ibuf->pid;
	255	if ((wbuf = ibuf_dynamic(datalen, MAX_IMSGSIZE)) == NULL) {
	256	return (NULL);
	257	}
	258	if (imsg_add(wbuf, &hdr, sizeof(hdr)) == -1)
	259	return (NULL);
	260
	261	return (wbuf);
	262	}
	263
996c9314	264	int imsg_add(struct ibuf msg, const void data, u_int16_t datalen)
8429abe0 RW	265	{
	266	if (datalen)
	267	if (ibuf_add(msg, data, datalen) == -1) {
	268	ibuf_free(msg);
	269	return (-1);
	270	}
	271	return (datalen);
	272	}
	273
996c9314	274	void imsg_close(struct imsgbuf ibuf, struct ibuf msg)
8429abe0	275	{
996c9314	276	struct imsg_hdr *hdr;
8429abe0 RW	277
	278	hdr = (struct imsg_hdr *)msg->buf;
	279
	280	hdr->flags &= ~IMSGF_HASFD;
	281	if (msg->fd != -1)
	282	hdr->flags \|= IMSGF_HASFD;
	283
	284	hdr->len = (u_int16_t)msg->wpos;
	285
	286	ibuf_close(&ibuf->w, msg);
	287	}
	288
996c9314	289	void imsg_free(struct imsg *imsg)
8429abe0 RW	290	{
	291	free(imsg->data);
	292	}
	293
996c9314	294	int imsg_get_fd(struct imsgbuf *ibuf)
8429abe0	295	{
996c9314 LB	296	int fd;
996c9314 LB	297	struct imsg_fd *ifd;
8429abe0 RW	298
	299	if ((ifd = TAILQ_FIRST(&ibuf->fds)) == NULL)
	300	return (-1);
	301
	302	fd = ifd->fd;
	303	TAILQ_REMOVE(&ibuf->fds, ifd, entry);
	304	free(ifd);
	305
	306	return (fd);
	307	}
	308
996c9314	309	int imsg_flush(struct imsgbuf *ibuf)
8429abe0 RW	310	{
	311	while (ibuf->w.queued)
	312	if (msgbuf_write(&ibuf->w) <= 0)
	313	return (-1);
	314	return (0);
	315	}
	316
996c9314	317	void imsg_clear(struct imsgbuf *ibuf)
8429abe0	318	{
996c9314	319	int fd;
8429abe0 RW	320
	321	msgbuf_clear(&ibuf->w);
	322	while ((fd = imsg_get_fd(ibuf)) != -1)
	323	close(fd);
	324	}