tmux/compat/imsg.c
Nicholas Marriott 66369416fc Update imsg.
2024-01-17 09:41:53 +00:00

449 lines
8.7 KiB
C

/* $OpenBSD: imsg.c,v 1.23 2023/12/12 15:47:41 claudio Exp $ */
/*
* Copyright (c) 2023 Claudio Jeker <claudio@openbsd.org>
* 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 <sys/types.h>
#include <sys/socket.h>
#include <sys/uio.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "compat.h"
#include "imsg.h"
struct imsg_fd {
TAILQ_ENTRY(imsg_fd) entry;
int fd;
};
int imsg_fd_overhead = 0;
static int imsg_dequeue_fd(struct imsgbuf *);
void
imsg_init(struct imsgbuf *imsgbuf, int fd)
{
msgbuf_init(&imsgbuf->w);
memset(&imsgbuf->r, 0, sizeof(imsgbuf->r));
imsgbuf->fd = fd;
imsgbuf->w.fd = fd;
imsgbuf->pid = getpid();
TAILQ_INIT(&imsgbuf->fds);
}
ssize_t
imsg_read(struct imsgbuf *imsgbuf)
{
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 = imsgbuf->r.buf + imsgbuf->r.wpos;
iov.iov_len = sizeof(imsgbuf->r.buf) - imsgbuf->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:
if (getdtablecount() + imsg_fd_overhead +
(int)((CMSG_SPACE(sizeof(int))-CMSG_SPACE(0))/sizeof(int))
>= getdtablesize()) {
errno = EAGAIN;
free(ifd);
return (-1);
}
if ((n = recvmsg(imsgbuf->fd, &msg, 0)) == -1) {
if (errno == EINTR)
goto again;
goto fail;
}
imsgbuf->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(&imsgbuf->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 *imsgbuf, struct imsg *imsg)
{
struct imsg m;
size_t av, left, datalen;
av = imsgbuf->r.wpos;
if (IMSG_HEADER_SIZE > av)
return (0);
memcpy(&m.hdr, imsgbuf->r.buf, sizeof(m.hdr));
if (m.hdr.len < IMSG_HEADER_SIZE ||
m.hdr.len > MAX_IMSGSIZE) {
errno = ERANGE;
return (-1);
}
if (m.hdr.len > av)
return (0);
m.fd = -1;
m.buf = NULL;
m.data = NULL;
datalen = m.hdr.len - IMSG_HEADER_SIZE;
imsgbuf->r.rptr = imsgbuf->r.buf + IMSG_HEADER_SIZE;
if (datalen != 0) {
if ((m.buf = ibuf_open(datalen)) == NULL)
return (-1);
if (ibuf_add(m.buf, imsgbuf->r.rptr, datalen) == -1) {
/* this should never fail */
ibuf_free(m.buf);
return (-1);
}
m.data = ibuf_data(m.buf);
}
if (m.hdr.flags & IMSGF_HASFD)
m.fd = imsg_dequeue_fd(imsgbuf);
if (m.hdr.len < av) {
left = av - m.hdr.len;
memmove(&imsgbuf->r.buf, imsgbuf->r.buf + m.hdr.len, left);
imsgbuf->r.wpos = left;
} else
imsgbuf->r.wpos = 0;
*imsg = m;
return (datalen + IMSG_HEADER_SIZE);
}
int
imsg_get_ibuf(struct imsg *imsg, struct ibuf *ibuf)
{
if (imsg->buf == NULL) {
errno = EBADMSG;
return (-1);
}
return ibuf_get_ibuf(imsg->buf, ibuf_size(imsg->buf), ibuf);
}
int
imsg_get_data(struct imsg *imsg, void *data, size_t len)
{
if (len == 0) {
errno = EINVAL;
return (-1);
}
if (imsg->buf == NULL || ibuf_size(imsg->buf) != len) {
errno = EBADMSG;
return (-1);
}
return ibuf_get(imsg->buf, data, len);
}
int
imsg_get_fd(struct imsg *imsg)
{
int fd = imsg->fd;
imsg->fd = -1;
return fd;
}
uint32_t
imsg_get_id(struct imsg *imsg)
{
return (imsg->hdr.peerid);
}
size_t
imsg_get_len(struct imsg *imsg)
{
if (imsg->buf == NULL)
return 0;
return ibuf_size(imsg->buf);
}
pid_t
imsg_get_pid(struct imsg *imsg)
{
return (imsg->hdr.pid);
}
uint32_t
imsg_get_type(struct imsg *imsg)
{
return (imsg->hdr.type);
}
int
imsg_compose(struct imsgbuf *imsgbuf, uint32_t type, uint32_t id, pid_t pid,
int fd, const void *data, size_t datalen)
{
struct ibuf *wbuf;
if ((wbuf = imsg_create(imsgbuf, type, id, pid, datalen)) == NULL)
return (-1);
if (imsg_add(wbuf, data, datalen) == -1)
return (-1);
ibuf_fd_set(wbuf, fd);
imsg_close(imsgbuf, wbuf);
return (1);
}
int
imsg_composev(struct imsgbuf *imsgbuf, uint32_t type, uint32_t id, pid_t pid,
int fd, const struct iovec *iov, int iovcnt)
{
struct ibuf *wbuf;
int i;
size_t datalen = 0;
for (i = 0; i < iovcnt; i++)
datalen += iov[i].iov_len;
if ((wbuf = imsg_create(imsgbuf, type, id, 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);
ibuf_fd_set(wbuf, fd);
imsg_close(imsgbuf, wbuf);
return (1);
}
/*
* Enqueue imsg with payload from ibuf buf. fd passing is not possible
* with this function.
*/
int
imsg_compose_ibuf(struct imsgbuf *imsgbuf, uint32_t type, uint32_t id,
pid_t pid, struct ibuf *buf)
{
struct ibuf *hdrbuf = NULL;
struct imsg_hdr hdr;
int save_errno;
if (ibuf_size(buf) + IMSG_HEADER_SIZE > MAX_IMSGSIZE) {
errno = ERANGE;
goto fail;
}
hdr.type = type;
hdr.len = ibuf_size(buf) + IMSG_HEADER_SIZE;
hdr.flags = 0;
hdr.peerid = id;
if ((hdr.pid = pid) == 0)
hdr.pid = imsgbuf->pid;
if ((hdrbuf = ibuf_open(IMSG_HEADER_SIZE)) == NULL)
goto fail;
if (imsg_add(hdrbuf, &hdr, sizeof(hdr)) == -1)
goto fail;
ibuf_close(&imsgbuf->w, hdrbuf);
ibuf_close(&imsgbuf->w, buf);
return (1);
fail:
save_errno = errno;
ibuf_free(buf);
ibuf_free(hdrbuf);
errno = save_errno;
return (-1);
}
/*
* Forward imsg to another channel. Any attached fd is closed.
*/
int
imsg_forward(struct imsgbuf *imsgbuf, struct imsg *msg)
{
struct ibuf *wbuf;
size_t len = 0;
if (msg->fd != -1) {
close(msg->fd);
msg->fd = -1;
}
if (msg->buf != NULL) {
ibuf_rewind(msg->buf);
len = ibuf_size(msg->buf);
}
if ((wbuf = imsg_create(imsgbuf, msg->hdr.type, msg->hdr.peerid,
msg->hdr.pid, len)) == NULL)
return (-1);
if (msg->buf != NULL) {
if (ibuf_add_buf(wbuf, msg->buf) == -1) {
ibuf_free(wbuf);
return (-1);
}
}
imsg_close(imsgbuf, wbuf);
return (1);
}
struct ibuf *
imsg_create(struct imsgbuf *imsgbuf, uint32_t type, uint32_t id, pid_t pid,
size_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 = id;
if ((hdr.pid = pid) == 0)
hdr.pid = imsgbuf->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, size_t datalen)
{
if (datalen)
if (ibuf_add(msg, data, datalen) == -1) {
ibuf_free(msg);
return (-1);
}
return (datalen);
}
void
imsg_close(struct imsgbuf *imsgbuf, struct ibuf *msg)
{
struct imsg_hdr *hdr;
hdr = (struct imsg_hdr *)msg->buf;
hdr->flags &= ~IMSGF_HASFD;
if (ibuf_fd_avail(msg))
hdr->flags |= IMSGF_HASFD;
hdr->len = ibuf_size(msg);
ibuf_close(&imsgbuf->w, msg);
}
void
imsg_free(struct imsg *imsg)
{
ibuf_free(imsg->buf);
}
static int
imsg_dequeue_fd(struct imsgbuf *imsgbuf)
{
int fd;
struct imsg_fd *ifd;
if ((ifd = TAILQ_FIRST(&imsgbuf->fds)) == NULL)
return (-1);
fd = ifd->fd;
TAILQ_REMOVE(&imsgbuf->fds, ifd, entry);
free(ifd);
return (fd);
}
int
imsg_flush(struct imsgbuf *imsgbuf)
{
while (imsgbuf->w.queued)
if (msgbuf_write(&imsgbuf->w) <= 0)
return (-1);
return (0);
}
void
imsg_clear(struct imsgbuf *imsgbuf)
{
int fd;
msgbuf_clear(&imsgbuf->w);
while ((fd = imsg_dequeue_fd(imsgbuf)) != -1)
close(fd);
}