[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 "openbsd-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
eac6e3f0	21	#include "openbsd-queue.h"
8429abe0 RW	22	#include "imsg.h"
8429abe0 RW	23
52535bee	24	int imsg_fd_overhead = 0;
8429abe0	25
52535bee	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	*/
52535bee RW	33	static int
52535bee RW	34	available_fds(unsigned int n)
eac6e3f0	35	{
52535bee RW	36	unsigned int i;
52535bee RW	37	int ret, fds[256];
eac6e3f0	38
52535bee	39	if (n > (sizeof(fds)/sizeof(fds[0])))
eac6e3f0 RW	40	return (1);
	41
	42	ret = 0;
	43	for (i = 0; i < n; i++) {
	44	fds[i] = -1;
	45	if ((fds[i] = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
	46	if (errno == EAFNOSUPPORT \|\| errno == EPROTONOSUPPORT)
	47	fds[i] = socket(AF_INET6, SOCK_DGRAM, 0);
	48	if (fds[i] < 0) {
	49	ret = 1;
	50	break;
	51	}
	52	}
	53	}
	54
	55	for (i = 0; i < n && fds[i] >= 0; i++)
	56	close(fds[i]);
	57
	58	return (ret);
	59	}
	60	#endif
	61
52535bee RW	62	void
52535bee RW	63	imsg_init(struct imsgbuf *ibuf, int fd)
8429abe0 RW	64	{
	65	msgbuf_init(&ibuf->w);
	66	memset(&ibuf->r, 0, sizeof(ibuf->r));
	67	ibuf->fd = fd;
	68	ibuf->w.fd = fd;
	69	ibuf->pid = getpid();
	70	TAILQ_INIT(&ibuf->fds);
	71	}
	72
52535bee RW	73	ssize_t
52535bee RW	74	imsg_read(struct imsgbuf *ibuf)
8429abe0	75	{
52535bee RW	76	struct msghdr msg;
52535bee RW	77	struct cmsghdr *cmsg;
8429abe0 RW	78	union {
8429abe0 RW	79	struct cmsghdr hdr;
52535bee	80	char buf[CMSG_SPACE(sizeof(int) * 1)];
8429abe0	81	} cmsgbuf;
52535bee RW	82	struct iovec iov;
	83	ssize_t n = -1;
	84	int fd;
	85	struct imsg_fd *ifd;
8429abe0 RW	86
	87	memset(&msg, 0, sizeof(msg));
	88	memset(&cmsgbuf, 0, sizeof(cmsgbuf));
	89
	90	iov.iov_base = ibuf->r.buf + ibuf->r.wpos;
	91	iov.iov_len = sizeof(ibuf->r.buf) - ibuf->r.wpos;
	92	msg.msg_iov = &iov;
	93	msg.msg_iovlen = 1;
	94	msg.msg_control = &cmsgbuf.buf;
	95	msg.msg_controllen = sizeof(cmsgbuf.buf);
	96
	97	if ((ifd = calloc(1, sizeof(struct imsg_fd))) == NULL)
	98	return (-1);
	99
	100	again:
eac6e3f0	101	#ifdef __OpenBSD__
52535bee RW	102	if (getdtablecount() + imsg_fd_overhead +
52535bee RW	103	(int)((CMSG_SPACE(sizeof(int))-CMSG_SPACE(0))/sizeof(int))
8429abe0	104	>= getdtablesize()) {
eac6e3f0	105	#else
52535bee RW	106	if (available_fds(imsg_fd_overhead +
52535bee RW	107	(CMSG_SPACE(sizeof(int))-CMSG_SPACE(0))/sizeof(int))) {
eac6e3f0	108	#endif
8429abe0 RW	109	errno = EAGAIN;
	110	free(ifd);
	111	return (-1);
	112	}
	113
	114	if ((n = recvmsg(ibuf->fd, &msg, 0)) == -1) {
	115	if (errno == EINTR)
	116	goto again;
	117	goto fail;
	118	}
	119
	120	ibuf->r.wpos += n;
	121
	122	for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL;
52535bee RW	123	cmsg = CMSG_NXTHDR(&msg, cmsg)) {
	124	if (cmsg->cmsg_level == SOL_SOCKET &&
	125	cmsg->cmsg_type == SCM_RIGHTS) {
8429abe0 RW	126	int i;
	127	int j;
	128
	129	/*
	130	* We only accept one file descriptor. Due to C
	131	* padding rules, our control buffer might contain
	132	* more than one fd, and we must close them.
	133	*/
52535bee RW	134	j = ((char *)cmsg + cmsg->cmsg_len -
52535bee RW	135	(char *)CMSG_DATA(cmsg)) / 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,
52535bee	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
52535bee RW	155	ssize_t
52535bee RW	156	imsg_get(struct imsgbuf ibuf, struct imsg imsg)
8429abe0	157	{
52535bee	158	size_t av, left, datalen;
8429abe0 RW	159
	160	av = ibuf->r.wpos;
	161
	162	if (IMSG_HEADER_SIZE > av)
	163	return (0);
	164
	165	memcpy(&imsg->hdr, ibuf->r.buf, sizeof(imsg->hdr));
52535bee RW	166	if (imsg->hdr.len < IMSG_HEADER_SIZE \|\|
52535bee RW	167	imsg->hdr.len > MAX_IMSGSIZE) {
8429abe0 RW	168	errno = ERANGE;
	169	return (-1);
	170	}
	171	if (imsg->hdr.len > av)
	172	return (0);
	173	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
	174	ibuf->r.rptr = ibuf->r.buf + IMSG_HEADER_SIZE;
	175	if (datalen == 0)
	176	imsg->data = NULL;
	177	else if ((imsg->data = malloc(datalen)) == NULL)
	178	return (-1);
	179
	180	if (imsg->hdr.flags & IMSGF_HASFD)
	181	imsg->fd = imsg_get_fd(ibuf);
	182	else
	183	imsg->fd = -1;
	184
dd3415b7	185	if (imsg->data)
52535bee	186	memcpy(imsg->data, ibuf->r.rptr, datalen);
8429abe0 RW	187
	188	if (imsg->hdr.len < av) {
	189	left = av - imsg->hdr.len;
	190	memmove(&ibuf->r.buf, ibuf->r.buf + imsg->hdr.len, left);
	191	ibuf->r.wpos = left;
	192	} else
	193	ibuf->r.wpos = 0;
	194
	195	return (datalen + IMSG_HEADER_SIZE);
	196	}
	197
52535bee RW	198	int
	199	imsg_compose(struct imsgbuf *ibuf, u_int32_t type, u_int32_t peerid,
	200	pid_t pid, int fd, const void *data, u_int16_t datalen)
8429abe0	201	{
52535bee	202	struct ibuf *wbuf;
8429abe0 RW	203
	204	if ((wbuf = imsg_create(ibuf, type, peerid, pid, datalen)) == NULL)
	205	return (-1);
	206
	207	if (imsg_add(wbuf, data, datalen) == -1)
	208	return (-1);
	209
	210	wbuf->fd = fd;
	211
	212	imsg_close(ibuf, wbuf);
	213
	214	return (1);
	215	}
	216
52535bee RW	217	int
	218	imsg_composev(struct imsgbuf *ibuf, u_int32_t type, u_int32_t peerid,
	219	pid_t pid, int fd, const struct iovec *iov, int iovcnt)
8429abe0	220	{
52535bee RW	221	struct ibuf *wbuf;
52535bee RW	222	int i, datalen = 0;
8429abe0 RW	223
	224	for (i = 0; i < iovcnt; i++)
	225	datalen += iov[i].iov_len;
	226
	227	if ((wbuf = imsg_create(ibuf, type, peerid, pid, datalen)) == NULL)
	228	return (-1);
	229
	230	for (i = 0; i < iovcnt; i++)
	231	if (imsg_add(wbuf, iov[i].iov_base, iov[i].iov_len) == -1)
	232	return (-1);
	233
	234	wbuf->fd = fd;
	235
	236	imsg_close(ibuf, wbuf);
	237
	238	return (1);
	239	}
	240
	241	/* ARGSUSED */
52535bee RW	242	struct ibuf *
	243	imsg_create(struct imsgbuf *ibuf, u_int32_t type, u_int32_t peerid,
	244	pid_t pid, u_int16_t datalen)
8429abe0	245	{
52535bee RW	246	struct ibuf *wbuf;
52535bee RW	247	struct imsg_hdr hdr;
8429abe0 RW	248
	249	datalen += IMSG_HEADER_SIZE;
	250	if (datalen > MAX_IMSGSIZE) {
	251	errno = ERANGE;
	252	return (NULL);
	253	}
	254
	255	hdr.type = type;
	256	hdr.flags = 0;
	257	hdr.peerid = peerid;
	258	if ((hdr.pid = pid) == 0)
	259	hdr.pid = ibuf->pid;
	260	if ((wbuf = ibuf_dynamic(datalen, MAX_IMSGSIZE)) == NULL) {
	261	return (NULL);
	262	}
	263	if (imsg_add(wbuf, &hdr, sizeof(hdr)) == -1)
	264	return (NULL);
	265
	266	return (wbuf);
	267	}
	268
52535bee RW	269	int
52535bee RW	270	imsg_add(struct ibuf msg, const void data, u_int16_t datalen)
8429abe0 RW	271	{
	272	if (datalen)
	273	if (ibuf_add(msg, data, datalen) == -1) {
	274	ibuf_free(msg);
	275	return (-1);
	276	}
	277	return (datalen);
	278	}
	279
52535bee RW	280	void
52535bee RW	281	imsg_close(struct imsgbuf ibuf, struct ibuf msg)
8429abe0	282	{
52535bee	283	struct imsg_hdr *hdr;
8429abe0 RW	284
	285	hdr = (struct imsg_hdr *)msg->buf;
	286
	287	hdr->flags &= ~IMSGF_HASFD;
	288	if (msg->fd != -1)
	289	hdr->flags \|= IMSGF_HASFD;
	290
	291	hdr->len = (u_int16_t)msg->wpos;
	292
	293	ibuf_close(&ibuf->w, msg);
	294	}
	295
52535bee RW	296	void
52535bee RW	297	imsg_free(struct imsg *imsg)
8429abe0 RW	298	{
	299	free(imsg->data);
	300	}
	301
52535bee RW	302	int
52535bee RW	303	imsg_get_fd(struct imsgbuf *ibuf)
8429abe0	304	{
52535bee RW	305	int fd;
52535bee RW	306	struct imsg_fd *ifd;
8429abe0 RW	307
	308	if ((ifd = TAILQ_FIRST(&ibuf->fds)) == NULL)
	309	return (-1);
	310
	311	fd = ifd->fd;
	312	TAILQ_REMOVE(&ibuf->fds, ifd, entry);
	313	free(ifd);
	314
	315	return (fd);
	316	}
	317
52535bee RW	318	int
52535bee RW	319	imsg_flush(struct imsgbuf *ibuf)
8429abe0 RW	320	{
	321	while (ibuf->w.queued)
	322	if (msgbuf_write(&ibuf->w) <= 0)
	323	return (-1);
	324	return (0);
	325	}
	326
52535bee RW	327	void
52535bee RW	328	imsg_clear(struct imsgbuf *ibuf)
8429abe0	329	{
52535bee	330	int fd;
8429abe0 RW	331
	332	msgbuf_clear(&ibuf->w);
	333	while ((fd = imsg_get_fd(ibuf)) != -1)
	334	close(fd);
	335	}