/* $OpenBSD: imsg.c,v 1.13 2015/12/09 11:54:12 tb Exp $ */
/*
* 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.
*
* $FreeBSD$
*/
#include <sys/types.h>
#include <sys/queue.h>
#include <sys/socket.h>
#include <sys/uio.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "imsg.h"
int imsg_fd_overhead = 0;
int imsg_get_fd(struct imsgbuf *);
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:
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(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;
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);
}
