[mirror_frr.git] / lib / imsg.c

// SPDX-License-Identifier: ISC
/*	$OpenBSD$	*/

/*
 * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
 */

#include <zebra.h>

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

static int imsg_fd_overhead = 0;

static 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 > (unsigned int)array_size(fds))
		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;
	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;
	}

	n = recvmsg(ibuf->fd, &msg, 0);
	if (n == -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, uint32_t type, uint32_t peerid,
		 pid_t pid, int fd, const void *data, uint16_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, uint32_t type, uint32_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, uint32_t type, uint32_t peerid,
			 pid_t pid, uint16_t datalen)
{
	struct ibuf *wbuf;
	struct imsg_hdr hdr;

	memset(&hdr, 0x00, IMSG_HEADER_SIZE);

	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, uint16_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 = (uint16_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_POP_FIRST(&ibuf->fds, entry)) == NULL)
		return -1;

	fd = ifd->fd;
	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
acddc0ed	1	// SPDX-License-Identifier: ISC
8429abe0 RW	2	/* $OpenBSD$ */
	3
	4	/*
	5	* Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
8429abe0 RW	6	*/
8429abe0 RW	7
eac6e3f0	8	#include <zebra.h>
8429abe0	9
97b5d752	10	#include "memory.h"
cd85bc2e	11	#include "queue.h"
8429abe0 RW	12	#include "imsg.h"
8429abe0 RW	13
c17faa4b	14	static int imsg_fd_overhead = 0;
8429abe0	15
c17faa4b	16	static int imsg_get_fd(struct imsgbuf *);
8429abe0	17
eac6e3f0 RW	18	#ifndef __OpenBSD__
	19	/*
	20	* The original code calls getdtablecount() which is OpenBSD specific. Use
	21	* available_fds() from OpenSMTPD instead.
	22	*/
996c9314	23	static int available_fds(unsigned int n)
eac6e3f0	24	{
996c9314 LB	25	unsigned int i;
996c9314 LB	26	int ret, fds[256];
eac6e3f0	27
97b5d752	28	if (n > (unsigned int)array_size(fds))
95f7965d	29	return 1;
eac6e3f0 RW	30
	31	ret = 0;
	32	for (i = 0; i < n; i++) {
	33	fds[i] = -1;
	34	if ((fds[i] = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
	35	if (errno == EAFNOSUPPORT \|\| errno == EPROTONOSUPPORT)
	36	fds[i] = socket(AF_INET6, SOCK_DGRAM, 0);
	37	if (fds[i] < 0) {
	38	ret = 1;
	39	break;
	40	}
	41	}
	42	}
	43
	44	for (i = 0; i < n && fds[i] >= 0; i++)
	45	close(fds[i]);
	46
	47	return (ret);
	48	}
	49	#endif
	50
996c9314	51	void imsg_init(struct imsgbuf *ibuf, int fd)
8429abe0 RW	52	{
	53	msgbuf_init(&ibuf->w);
	54	memset(&ibuf->r, 0, sizeof(ibuf->r));
	55	ibuf->fd = fd;
	56	ibuf->w.fd = fd;
	57	ibuf->pid = getpid();
	58	TAILQ_INIT(&ibuf->fds);
	59	}
	60
996c9314	61	ssize_t imsg_read(struct imsgbuf *ibuf)
8429abe0	62	{
996c9314 LB	63	struct msghdr msg;
996c9314 LB	64	struct cmsghdr *cmsg;
8429abe0 RW	65	union {
8429abe0 RW	66	struct cmsghdr hdr;
996c9314	67	char buf[CMSG_SPACE(sizeof(int) * 1)];
8429abe0	68	} cmsgbuf;
996c9314	69	struct iovec iov;
a2b6e694	70	ssize_t n;
996c9314 LB	71	int fd;
996c9314 LB	72	struct imsg_fd *ifd;
8429abe0 RW	73
	74	memset(&msg, 0, sizeof(msg));
	75	memset(&cmsgbuf, 0, sizeof(cmsgbuf));
	76
	77	iov.iov_base = ibuf->r.buf + ibuf->r.wpos;
	78	iov.iov_len = sizeof(ibuf->r.buf) - ibuf->r.wpos;
	79	msg.msg_iov = &iov;
	80	msg.msg_iovlen = 1;
	81	msg.msg_control = &cmsgbuf.buf;
	82	msg.msg_controllen = sizeof(cmsgbuf.buf);
	83
	84	if ((ifd = calloc(1, sizeof(struct imsg_fd))) == NULL)
95f7965d	85	return -1;
8429abe0 RW	86
8429abe0 RW	87	again:
eac6e3f0	88	#ifdef __OpenBSD__
996c9314 LB	89	if (getdtablecount() + imsg_fd_overhead
	90	+ (int)((CMSG_SPACE(sizeof(int)) - CMSG_SPACE(0))
	91	/ sizeof(int))
8429abe0	92	>= getdtablesize()) {
eac6e3f0	93	#else
996c9314 LB	94	if (available_fds(imsg_fd_overhead
	95	+ (CMSG_SPACE(sizeof(int)) - CMSG_SPACE(0))
	96	/ sizeof(int))) {
eac6e3f0	97	#endif
8429abe0 RW	98	errno = EAGAIN;
8429abe0 RW	99	free(ifd);
95f7965d	100	return -1;
8429abe0 RW	101	}
8429abe0 RW	102
a2b6e694	103	n = recvmsg(ibuf->fd, &msg, 0);
a2b6e694	104	if (n == -1) {
8429abe0 RW	105	if (errno == EINTR)
	106	goto again;
	107	goto fail;
	108	}
	109
	110	ibuf->r.wpos += n;
	111
	112	for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL;
996c9314 LB	113	cmsg = CMSG_NXTHDR(&msg, cmsg)) {
	114	if (cmsg->cmsg_level == SOL_SOCKET
	115	&& cmsg->cmsg_type == SCM_RIGHTS) {
8429abe0 RW	116	int i;
	117	int j;
	118
	119	/*
	120	* We only accept one file descriptor. Due to C
	121	* padding rules, our control buffer might contain
	122	* more than one fd, and we must close them.
	123	*/
996c9314 LB	124	j = ((char *)cmsg + cmsg->cmsg_len
	125	- (char *)CMSG_DATA(cmsg))
	126	/ sizeof(int);
8429abe0 RW	127	for (i = 0; i < j; i++) {
	128	fd = ((int *)CMSG_DATA(cmsg))[i];
	129	if (ifd != NULL) {
	130	ifd->fd = fd;
	131	TAILQ_INSERT_TAIL(&ibuf->fds, ifd,
996c9314	132	entry);
8429abe0 RW	133	ifd = NULL;
	134	} else
	135	close(fd);
	136	}
	137	}
	138	/* we do not handle other ctl data level */
	139	}
	140
	141	fail:
	142	free(ifd);
	143	return (n);
	144	}
	145
996c9314	146	ssize_t imsg_get(struct imsgbuf ibuf, struct imsg imsg)
8429abe0	147	{
996c9314	148	size_t av, left, datalen;
8429abe0 RW	149
	150	av = ibuf->r.wpos;
	151
	152	if (IMSG_HEADER_SIZE > av)
95f7965d	153	return 0;
8429abe0 RW	154
8429abe0 RW	155	memcpy(&imsg->hdr, ibuf->r.buf, sizeof(imsg->hdr));
996c9314	156	if (imsg->hdr.len < IMSG_HEADER_SIZE \|\| imsg->hdr.len > MAX_IMSGSIZE) {
8429abe0	157	errno = ERANGE;
95f7965d	158	return -1;
8429abe0 RW	159	}
8429abe0 RW	160	if (imsg->hdr.len > av)
95f7965d	161	return 0;
8429abe0 RW	162	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
	163	ibuf->r.rptr = ibuf->r.buf + IMSG_HEADER_SIZE;
	164	if (datalen == 0)
	165	imsg->data = NULL;
	166	else if ((imsg->data = malloc(datalen)) == NULL)
95f7965d	167	return -1;
8429abe0 RW	168
	169	if (imsg->hdr.flags & IMSGF_HASFD)
	170	imsg->fd = imsg_get_fd(ibuf);
	171	else
	172	imsg->fd = -1;
	173
dd3415b7	174	if (imsg->data)
996c9314	175	memcpy(imsg->data, ibuf->r.rptr, datalen);
8429abe0 RW	176
	177	if (imsg->hdr.len < av) {
	178	left = av - imsg->hdr.len;
	179	memmove(&ibuf->r.buf, ibuf->r.buf + imsg->hdr.len, left);
	180	ibuf->r.wpos = left;
	181	} else
	182	ibuf->r.wpos = 0;
	183
	184	return (datalen + IMSG_HEADER_SIZE);
	185	}
	186
d7c0a89a QY	187	int imsg_compose(struct imsgbuf *ibuf, uint32_t type, uint32_t peerid,
d7c0a89a QY	188	pid_t pid, int fd, const void *data, uint16_t datalen)
8429abe0	189	{
996c9314	190	struct ibuf *wbuf;
8429abe0 RW	191
8429abe0 RW	192	if ((wbuf = imsg_create(ibuf, type, peerid, pid, datalen)) == NULL)
95f7965d	193	return -1;
8429abe0 RW	194
8429abe0 RW	195	if (imsg_add(wbuf, data, datalen) == -1)
95f7965d	196	return -1;
8429abe0 RW	197
	198	wbuf->fd = fd;
	199
	200	imsg_close(ibuf, wbuf);
	201
95f7965d	202	return 1;
8429abe0 RW	203	}
8429abe0 RW	204
d7c0a89a	205	int imsg_composev(struct imsgbuf *ibuf, uint32_t type, uint32_t peerid,
996c9314	206	pid_t pid, int fd, const struct iovec *iov, int iovcnt)
8429abe0	207	{
996c9314 LB	208	struct ibuf *wbuf;
996c9314 LB	209	int i, datalen = 0;
8429abe0 RW	210
	211	for (i = 0; i < iovcnt; i++)
	212	datalen += iov[i].iov_len;
	213
	214	if ((wbuf = imsg_create(ibuf, type, peerid, pid, datalen)) == NULL)
95f7965d	215	return -1;
8429abe0 RW	216
	217	for (i = 0; i < iovcnt; i++)
	218	if (imsg_add(wbuf, iov[i].iov_base, iov[i].iov_len) == -1)
95f7965d	219	return -1;
8429abe0 RW	220
	221	wbuf->fd = fd;
	222
	223	imsg_close(ibuf, wbuf);
	224
95f7965d	225	return 1;
8429abe0 RW	226	}
	227
	228	/* ARGSUSED */
d7c0a89a QY	229	struct ibuf imsg_create(struct imsgbuf ibuf, uint32_t type, uint32_t peerid,
d7c0a89a QY	230	pid_t pid, uint16_t datalen)
8429abe0	231	{
996c9314 LB	232	struct ibuf *wbuf;
996c9314 LB	233	struct imsg_hdr hdr;
8429abe0	234
c2fb17b5 QY	235	memset(&hdr, 0x00, IMSG_HEADER_SIZE);
c2fb17b5 QY	236
8429abe0 RW	237	datalen += IMSG_HEADER_SIZE;
	238	if (datalen > MAX_IMSGSIZE) {
	239	errno = ERANGE;
95f7965d	240	return NULL;
8429abe0 RW	241	}
	242
	243	hdr.type = type;
	244	hdr.flags = 0;
	245	hdr.peerid = peerid;
	246	if ((hdr.pid = pid) == 0)
	247	hdr.pid = ibuf->pid;
	248	if ((wbuf = ibuf_dynamic(datalen, MAX_IMSGSIZE)) == NULL) {
95f7965d	249	return NULL;
8429abe0 RW	250	}
8429abe0 RW	251	if (imsg_add(wbuf, &hdr, sizeof(hdr)) == -1)
95f7965d	252	return NULL;
8429abe0 RW	253
	254	return (wbuf);
	255	}
	256
d7c0a89a	257	int imsg_add(struct ibuf msg, const void data, uint16_t datalen)
8429abe0 RW	258	{
	259	if (datalen)
	260	if (ibuf_add(msg, data, datalen) == -1) {
	261	ibuf_free(msg);
95f7965d	262	return -1;
8429abe0 RW	263	}
	264	return (datalen);
	265	}
	266
996c9314	267	void imsg_close(struct imsgbuf ibuf, struct ibuf msg)
8429abe0	268	{
996c9314	269	struct imsg_hdr *hdr;
8429abe0 RW	270
	271	hdr = (struct imsg_hdr *)msg->buf;
	272
	273	hdr->flags &= ~IMSGF_HASFD;
	274	if (msg->fd != -1)
	275	hdr->flags \|= IMSGF_HASFD;
	276
d7c0a89a	277	hdr->len = (uint16_t)msg->wpos;
8429abe0 RW	278
	279	ibuf_close(&ibuf->w, msg);
	280	}
	281
996c9314	282	void imsg_free(struct imsg *imsg)
8429abe0 RW	283	{
	284	free(imsg->data);
	285	}
	286
996c9314	287	int imsg_get_fd(struct imsgbuf *ibuf)
8429abe0	288	{
996c9314 LB	289	int fd;
996c9314 LB	290	struct imsg_fd *ifd;
8429abe0	291
a43ad4fe	292	if ((ifd = TAILQ_POP_FIRST(&ibuf->fds, entry)) == NULL)
95f7965d	293	return -1;
8429abe0 RW	294
8429abe0 RW	295	fd = ifd->fd;
8429abe0 RW	296	free(ifd);
	297
	298	return (fd);
	299	}
	300
996c9314	301	int imsg_flush(struct imsgbuf *ibuf)
8429abe0 RW	302	{
	303	while (ibuf->w.queued)
	304	if (msgbuf_write(&ibuf->w) <= 0)
95f7965d DA	305	return -1;
95f7965d DA	306	return 0;
8429abe0 RW	307	}
8429abe0 RW	308
996c9314	309	void imsg_clear(struct imsgbuf *ibuf)
8429abe0	310	{
996c9314	311	int fd;
8429abe0 RW	312
	313	msgbuf_clear(&ibuf->w);
	314	while ((fd = imsg_get_fd(ibuf)) != -1)
	315	close(fd);
	316	}