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/* $OpenBSD: msg.c,v 1.3 2004/09/25 12:22:54 jfb Exp $ */
/*
* Copyright (c) 2002 Matthieu Herrb
* Copyright (c) 2001 Niels Provos <provos@citi.umich.edu>
* Copyright (c) 2004 Jean-Francois Brousseau
*
* 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 MIND, 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.
*
* This code was adapted from the tcpdump source
*/
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/uio.h>
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include "log.h"
#include "cvsd.h"
/*
* cvsd_sendfd()
*
* Pass a file descriptor <fd> to the other endpoint of the socket <sock>.
*/
int
cvsd_sendfd(int sock, int fd)
{
struct msghdr msg;
char tmp[CMSG_SPACE(sizeof(int))];
struct cmsghdr *cmsg;
struct iovec vec;
int result = 0;
ssize_t n;
memset(&msg, 0, sizeof(msg));
if (fd >= 0) {
msg.msg_control = (caddr_t)tmp;
msg.msg_controllen = CMSG_LEN(sizeof(int));
cmsg = CMSG_FIRSTHDR(&msg);
cmsg->cmsg_len = CMSG_LEN(sizeof(int));
cmsg->cmsg_level = SOL_SOCKET;
cmsg->cmsg_type = SCM_RIGHTS;
*(int *)CMSG_DATA(cmsg) = fd;
} else
result = errno;
vec.iov_base = &result;
vec.iov_len = sizeof(int);
msg.msg_iov = &vec;
msg.msg_iovlen = 1;
if ((n = sendmsg(sock, &msg, 0)) == -1) {
cvs_log(LP_ERRNO, "failed to pass file descriptor");
return (-1);
}
if (n != sizeof(int))
cvs_log(LP_WARN, "unexpected return count from sendmsg()");
return (0);
}
/*
* cvsd_recvfd()
*
* Receive a file descriptor over the socket <sock>. Returns the descriptor
* on success, or -1 on failure.
*/
int
cvsd_recvfd(int sock)
{
struct msghdr msg;
char tmp[CMSG_SPACE(sizeof(int))];
struct cmsghdr *cmsg;
struct iovec vec;
ssize_t n;
int result;
int fd;
memset(&msg, 0, sizeof(msg));
vec.iov_base = &result;
vec.iov_len = sizeof(int);
msg.msg_iov = &vec;
msg.msg_iovlen = 1;
msg.msg_control = tmp;
msg.msg_controllen = sizeof(tmp);
if ((n = recvmsg(sock, &msg, 0)) == -1)
cvs_log(LP_ERRNO, "failed to receive descriptor");
if (n != sizeof(int))
cvs_log(LP_WARN, "recvmsg: expected received 1 got %ld",
(long)n);
if (result == 0) {
cmsg = CMSG_FIRSTHDR(&msg);
if (cmsg->cmsg_type != SCM_RIGHTS)
cvs_log(LP_WARN,
"unexpected message type in descriptor reception");
fd = (*(int *)CMSG_DATA(cmsg));
return (fd);
} else {
errno = result;
return (-1);
}
}
/*
* cvsd_sendmsg()
*
* Send a message of type <type> along with the first <len> bytes of data
* from <data> (which can be up to CVSD_MSG_MAXLEN bytes) on the descriptor
* <fd>.
* Returns 0 on success, or -1 on failure.
*/
int
cvsd_sendmsg(int fd, u_int type, const void *data, size_t len)
{
int cnt;
struct iovec iov[2];
struct cvsd_msg msg;
if (len > CVSD_MSG_MAXLEN) {
cvs_log(LP_ERR, "message too large");
return (-1);
}
memset(&msg, 0, sizeof(msg));
cnt = 1;
iov[0].iov_base = &msg;
iov[0].iov_len = sizeof(msg);
msg.cm_type = type;
if (type != CVSD_MSG_PASSFD) {
msg.cm_len = len;
iov[1].iov_base = (void *)data;
iov[1].iov_len = len;
cnt = 2;
}
else
msg.cm_len = sizeof(int); /* dummy */
if (writev(fd, iov, cnt) == -1) {
cvs_log(LP_ERRNO, "failed to send message");
return (-1);
}
if (type == CVSD_MSG_PASSFD) {
/* pass the file descriptor for real */
cvsd_sendfd(fd, *(int *)data);
}
return (0);
}
/*
* cvsd_recvmsg()
*
* Read a message from the file descriptor <fd> and store the message data
* in the <dst> buffer. The <len> parameter should contain the maximum
* length of data that can be stored in <dst>, and will contain the actual
* size of data stored on return. The message type is stored in <type>.
* Returns 1 if a message was read, 0 if the remote end closed the message
* socket and no further messages can be read, or -1 on failure.
*/
int
cvsd_recvmsg(int fd, u_int *type, void *dst, size_t *len)
{
int sfd;
ssize_t ret;
struct cvsd_msg msg;
if ((ret = read(fd, &msg, sizeof(msg))) == -1) {
cvs_log(LP_ERRNO, "failed to read message header");
return (-1);
}
else if (ret == 0)
return (0);
if (*len < msg.cm_len) {
cvs_log(LP_ERR, "buffer size too small for message data");
return (-1);
}
if (msg.cm_type == CVSD_MSG_PASSFD) {
sfd = cvsd_recvfd(fd);
if (sfd == -1)
return (-1);
*(int *)dst = sfd;
*len = sizeof(sfd);
}
else {
ret = read(fd, dst, msg.cm_len);
if (ret == -1) {
cvs_log(LP_ERRNO, "failed to read message");
return (-1);
}
else if (ret == 0) {
}
*len = (size_t)ret;
}
*type = msg.cm_type;
return (0);
}
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