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/* $OpenBSD: monitor_fdpass.c,v 1.18 2008/11/30 11:59:26 dtucker Exp $ */
/*
* Copyright 2001 Niels Provos <provos@citi.umich.edu>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "includes.h"
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/uio.h>
#ifdef HAVE_SYS_UN_H
#include <sys/un.h>
#endif
#include <sys/utsname.h>
#include <errno.h>
#include <string.h>
#include <stdarg.h>
#include "log.h"
#include "monitor_fdpass.h"
static int
cmsg_type_is_broken(void)
{
static int broken_cmsg_type = -1;
if (broken_cmsg_type != -1)
return broken_cmsg_type;
else {
struct utsname uts;
/* If uname() fails, play safe and assume that cmsg_type
* isn't broken.
*/
if (!uname(&uts) &&
strcmp(uts.sysname, "Linux") == 0 &&
strncmp(uts.release, "2.0.", 4) == 0)
broken_cmsg_type = 1;
else
broken_cmsg_type = 0;
}
return broken_cmsg_type;
}
int
mm_send_fd(int sock, int fd)
{
#if defined(HAVE_SENDMSG) && (defined(HAVE_ACCRIGHTS_IN_MSGHDR) || defined(HAVE_CONTROL_IN_MSGHDR))
struct msghdr msg;
#ifndef HAVE_ACCRIGHTS_IN_MSGHDR
union {
struct cmsghdr hdr;
char buf[CMSG_SPACE(sizeof(int))];
} cmsgbuf;
struct cmsghdr *cmsg;
#endif
struct iovec vec;
char ch = '\0';
ssize_t n;
memset(&msg, 0, sizeof(msg));
#ifdef HAVE_ACCRIGHTS_IN_MSGHDR
msg.msg_accrights = (caddr_t)&fd;
msg.msg_accrightslen = sizeof(fd);
#else
msg.msg_control = (caddr_t)&cmsgbuf.buf;
msg.msg_controllen = sizeof(cmsgbuf.buf);
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;
#endif
vec.iov_base = &ch;
vec.iov_len = 1;
msg.msg_iov = &vec;
msg.msg_iovlen = 1;
while ((n = sendmsg(sock, &msg, 0)) == -1 && (errno == EAGAIN ||
errno == EINTR))
debug3("%s: sendmsg(%d): %s", __func__, fd, strerror(errno));
if (n == -1) {
error("%s: sendmsg(%d): %s", __func__, fd,
strerror(errno));
return -1;
}
if (n != 1) {
error("%s: sendmsg: expected sent 1 got %ld",
__func__, (long)n);
return -1;
}
return 0;
#else
error("%s: file descriptor passing not supported", __func__);
return -1;
#endif
}
int
mm_receive_fd(int sock)
{
#if defined(HAVE_RECVMSG) && (defined(HAVE_ACCRIGHTS_IN_MSGHDR) || defined(HAVE_CONTROL_IN_MSGHDR))
struct msghdr msg;
#ifndef HAVE_ACCRIGHTS_IN_MSGHDR
union {
struct cmsghdr hdr;
char buf[CMSG_SPACE(sizeof(int))];
} cmsgbuf;
struct cmsghdr *cmsg;
#endif
struct iovec vec;
ssize_t n;
char ch;
int fd;
memset(&msg, 0, sizeof(msg));
vec.iov_base = &ch;
vec.iov_len = 1;
msg.msg_iov = &vec;
msg.msg_iovlen = 1;
#ifdef HAVE_ACCRIGHTS_IN_MSGHDR
msg.msg_accrights = (caddr_t)&fd;
msg.msg_accrightslen = sizeof(fd);
#else
msg.msg_control = &cmsgbuf.buf;
msg.msg_controllen = sizeof(cmsgbuf.buf);
#endif
while ((n = recvmsg(sock, &msg, 0)) == -1 && (errno == EAGAIN ||
errno == EINTR))
debug3("%s: recvmsg: %s", __func__, strerror(errno));
if (n == -1) {
error("%s: recvmsg: %s", __func__, strerror(errno));
return -1;
}
if (n != 1) {
error("%s: recvmsg: expected received 1 got %ld",
__func__, (long)n);
return -1;
}
#ifdef HAVE_ACCRIGHTS_IN_MSGHDR
if (msg.msg_accrightslen != sizeof(fd)) {
error("%s: no fd", __func__);
return -1;
}
#else
cmsg = CMSG_FIRSTHDR(&msg);
if (cmsg == NULL) {
error("%s: no message header", __func__);
return -1;
}
if (!cmsg_type_is_broken() && cmsg->cmsg_type != SCM_RIGHTS) {
error("%s: expected type %d got %d", __func__,
SCM_RIGHTS, cmsg->cmsg_type);
return -1;
}
fd = (*(int *)CMSG_DATA(cmsg));
#endif
return fd;
#else
error("%s: file descriptor passing not supported", __func__);
return -1;
#endif
}
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