monitor_fdpass.c revision 294328 
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#include <string.h>
38#include <stdarg.h>
39
40#ifdef HAVE_POLL_H
41# include <poll.h>
42#else
43# ifdef HAVE_SYS_POLL_H
44#  include <sys/poll.h>
45# endif
46#endif
47
48#include "log.h"
49#include "monitor_fdpass.h"
50
51int
52mm_send_fd(int sock, int fd)
53{
54#if defined(HAVE_SENDMSG) && (defined(HAVE_ACCRIGHTS_IN_MSGHDR) || defined(HAVE_CONTROL_IN_MSGHDR))
55	struct msghdr msg;
56#ifndef HAVE_ACCRIGHTS_IN_MSGHDR
57	union {
58		struct cmsghdr hdr;
59		char buf[CMSG_SPACE(sizeof(int))];
60	} cmsgbuf;
61	struct cmsghdr *cmsg;
62#endif
63	struct iovec vec;
64	char ch = '\0';
65	ssize_t n;
66	struct pollfd pfd;
67
68	memset(&msg, 0, sizeof(msg));
69#ifdef HAVE_ACCRIGHTS_IN_MSGHDR
70	msg.msg_accrights = (caddr_t)&fd;
71	msg.msg_accrightslen = sizeof(fd);
72#else
73	msg.msg_control = (caddr_t)&cmsgbuf.buf;
74	msg.msg_controllen = sizeof(cmsgbuf.buf);
75	cmsg = CMSG_FIRSTHDR(&msg);
76	cmsg->cmsg_len = CMSG_LEN(sizeof(int));
77	cmsg->cmsg_level = SOL_SOCKET;
78	cmsg->cmsg_type = SCM_RIGHTS;
79	*(int *)CMSG_DATA(cmsg) = fd;
80#endif
81
82	vec.iov_base = &ch;
83	vec.iov_len = 1;
84	msg.msg_iov = &vec;
85	msg.msg_iovlen = 1;
86
87	pfd.fd = sock;
88	pfd.events = POLLOUT;
89	while ((n = sendmsg(sock, &msg, 0)) == -1 &&
90	    (errno == EAGAIN || errno == EINTR)) {
91		debug3("%s: sendmsg(%d): %s", __func__, fd, strerror(errno));
92		(void)poll(&pfd, 1, -1);
93	}
94	if (n == -1) {
95		error("%s: sendmsg(%d): %s", __func__, fd,
96		    strerror(errno));
97		return -1;
98	}
99
100	if (n != 1) {
101		error("%s: sendmsg: expected sent 1 got %ld",
102		    __func__, (long)n);
103		return -1;
104	}
105	return 0;
106#else
107	error("%s: file descriptor passing not supported", __func__);
108	return -1;
109#endif
110}
111
112int
113mm_receive_fd(int sock)
114{
115#if defined(HAVE_RECVMSG) && (defined(HAVE_ACCRIGHTS_IN_MSGHDR) || defined(HAVE_CONTROL_IN_MSGHDR))
116	struct msghdr msg;
117#ifndef HAVE_ACCRIGHTS_IN_MSGHDR
118	union {
119		struct cmsghdr hdr;
120		char buf[CMSG_SPACE(sizeof(int))];
121	} cmsgbuf;
122	struct cmsghdr *cmsg;
123#endif
124	struct iovec vec;
125	ssize_t n;
126	char ch;
127	int fd;
128	struct pollfd pfd;
129
130	memset(&msg, 0, sizeof(msg));
131	vec.iov_base = &ch;
132	vec.iov_len = 1;
133	msg.msg_iov = &vec;
134	msg.msg_iovlen = 1;
135#ifdef HAVE_ACCRIGHTS_IN_MSGHDR
136	msg.msg_accrights = (caddr_t)&fd;
137	msg.msg_accrightslen = sizeof(fd);
138#else
139	msg.msg_control = &cmsgbuf.buf;
140	msg.msg_controllen = sizeof(cmsgbuf.buf);
141#endif
142
143	pfd.fd = sock;
144	pfd.events = POLLIN;
145	while ((n = recvmsg(sock, &msg, 0)) == -1 &&
146	    (errno == EAGAIN || errno == EINTR)) {
147		debug3("%s: recvmsg: %s", __func__, strerror(errno));
148		(void)poll(&pfd, 1, -1);
149	}
150	if (n == -1) {
151		error("%s: recvmsg: %s", __func__, strerror(errno));
152		return -1;
153	}
154
155	if (n != 1) {
156		error("%s: recvmsg: expected received 1 got %ld",
157		    __func__, (long)n);
158		return -1;
159	}
160
161#ifdef HAVE_ACCRIGHTS_IN_MSGHDR
162	if (msg.msg_accrightslen != sizeof(fd)) {
163		error("%s: no fd", __func__);
164		return -1;
165	}
166#else
167	cmsg = CMSG_FIRSTHDR(&msg);
168	if (cmsg == NULL) {
169		error("%s: no message header", __func__);
170		return -1;
171	}
172
173#ifndef BROKEN_CMSG_TYPE
174	if (cmsg->cmsg_type != SCM_RIGHTS) {
175		error("%s: expected type %d got %d", __func__,
176		    SCM_RIGHTS, cmsg->cmsg_type);
177		return -1;
178	}
179#endif
180	fd = (*(int *)CMSG_DATA(cmsg));
181#endif
182	return fd;
183#else
184	error("%s: file descriptor passing not supported", __func__);
185	return -1;
186#endif
187}
188