1/* $OpenBSD: monitor_fdpass.c,v 1.19 2010/01/12 00:58:25 djm Exp $ */
2/*
3 * Copyright 2001 Niels Provos <provos@citi.umich.edu>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#include "includes.h"
28
29#include <sys/types.h>
30#include <sys/socket.h>
31#include <sys/uio.h>
32#ifdef HAVE_SYS_UN_H
33#include <sys/un.h>
34#endif
35
36#include <errno.h>
37#ifdef HAVE_POLL_H
38#include <poll.h>
39#endif
40#include <string.h>
41#include <stdarg.h>
42
43#include "log.h"
44#include "monitor_fdpass.h"
45
46int
47mm_send_fd(int sock, int fd)
48{
49#if defined(HAVE_SENDMSG) && (defined(HAVE_ACCRIGHTS_IN_MSGHDR) || defined(HAVE_CONTROL_IN_MSGHDR))
50	struct msghdr msg;
51#ifndef HAVE_ACCRIGHTS_IN_MSGHDR
52	union {
53		struct cmsghdr hdr;
54		char buf[CMSG_SPACE(sizeof(int))];
55	} cmsgbuf;
56	struct cmsghdr *cmsg;
57#endif
58	struct iovec vec;
59	char ch = '\0';
60	ssize_t n;
61	struct pollfd pfd;
62
63	memset(&msg, 0, sizeof(msg));
64#ifdef HAVE_ACCRIGHTS_IN_MSGHDR
65	msg.msg_accrights = (caddr_t)&fd;
66	msg.msg_accrightslen = sizeof(fd);
67#else
68	msg.msg_control = (caddr_t)&cmsgbuf.buf;
69	msg.msg_controllen = sizeof(cmsgbuf.buf);
70	cmsg = CMSG_FIRSTHDR(&msg);
71	cmsg->cmsg_len = CMSG_LEN(sizeof(int));
72	cmsg->cmsg_level = SOL_SOCKET;
73	cmsg->cmsg_type = SCM_RIGHTS;
74	*(int *)CMSG_DATA(cmsg) = fd;
75#endif
76
77	vec.iov_base = &ch;
78	vec.iov_len = 1;
79	msg.msg_iov = &vec;
80	msg.msg_iovlen = 1;
81
82	pfd.fd = sock;
83	pfd.events = POLLOUT;
84	while ((n = sendmsg(sock, &msg, 0)) == -1 &&
85	    (errno == EAGAIN || errno == EINTR)) {
86		debug3("%s: sendmsg(%d): %s", __func__, fd, strerror(errno));
87		(void)poll(&pfd, 1, -1);
88	}
89	if (n == -1) {
90		error("%s: sendmsg(%d): %s", __func__, fd,
91		    strerror(errno));
92		return -1;
93	}
94
95	if (n != 1) {
96		error("%s: sendmsg: expected sent 1 got %ld",
97		    __func__, (long)n);
98		return -1;
99	}
100	return 0;
101#else
102	error("%s: file descriptor passing not supported", __func__);
103	return -1;
104#endif
105}
106
107int
108mm_receive_fd(int sock)
109{
110#if defined(HAVE_RECVMSG) && (defined(HAVE_ACCRIGHTS_IN_MSGHDR) || defined(HAVE_CONTROL_IN_MSGHDR))
111	struct msghdr msg;
112#ifndef HAVE_ACCRIGHTS_IN_MSGHDR
113	union {
114		struct cmsghdr hdr;
115		char buf[CMSG_SPACE(sizeof(int))];
116	} cmsgbuf;
117	struct cmsghdr *cmsg;
118#endif
119	struct iovec vec;
120	ssize_t n;
121	char ch;
122	int fd;
123	struct pollfd pfd;
124
125	memset(&msg, 0, sizeof(msg));
126	vec.iov_base = &ch;
127	vec.iov_len = 1;
128	msg.msg_iov = &vec;
129	msg.msg_iovlen = 1;
130#ifdef HAVE_ACCRIGHTS_IN_MSGHDR
131	msg.msg_accrights = (caddr_t)&fd;
132	msg.msg_accrightslen = sizeof(fd);
133#else
134	msg.msg_control = &cmsgbuf.buf;
135	msg.msg_controllen = sizeof(cmsgbuf.buf);
136#endif
137
138	pfd.fd = sock;
139	pfd.events = POLLIN;
140	while ((n = recvmsg(sock, &msg, 0)) == -1 &&
141	    (errno == EAGAIN || errno == EINTR)) {
142		debug3("%s: recvmsg: %s", __func__, strerror(errno));
143		(void)poll(&pfd, 1, -1);
144	}
145	if (n == -1) {
146		error("%s: recvmsg: %s", __func__, strerror(errno));
147		return -1;
148	}
149
150	if (n != 1) {
151		error("%s: recvmsg: expected received 1 got %ld",
152		    __func__, (long)n);
153		return -1;
154	}
155
156#ifdef HAVE_ACCRIGHTS_IN_MSGHDR
157	if (msg.msg_accrightslen != sizeof(fd)) {
158		error("%s: no fd", __func__);
159		return -1;
160	}
161#else
162	cmsg = CMSG_FIRSTHDR(&msg);
163	if (cmsg == NULL) {
164		error("%s: no message header", __func__);
165		return -1;
166	}
167
168#ifndef BROKEN_CMSG_TYPE
169	if (cmsg->cmsg_type != SCM_RIGHTS) {
170		error("%s: expected type %d got %d", __func__,
171		    SCM_RIGHTS, cmsg->cmsg_type);
172		return -1;
173	}
174#endif
175	fd = (*(int *)CMSG_DATA(cmsg));
176#endif
177	return fd;
178#else
179	error("%s: file descriptor passing not supported", __func__);
180	return -1;
181#endif
182}
183