monitor_fdpass.c revision 295367 
1/* $OpenBSD: monitor_fdpass.c,v 1.20 2015/02/25 23:05:47 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	memset(&cmsgbuf, 0, sizeof(cmsgbuf));
74	msg.msg_control = (caddr_t)&cmsgbuf.buf;
75	msg.msg_controllen = sizeof(cmsgbuf.buf);
76	cmsg = CMSG_FIRSTHDR(&msg);
77	cmsg->cmsg_len = CMSG_LEN(sizeof(int));
78	cmsg->cmsg_level = SOL_SOCKET;
79	cmsg->cmsg_type = SCM_RIGHTS;
80	*(int *)CMSG_DATA(cmsg) = fd;
81#endif
82
83	vec.iov_base = &ch;
84	vec.iov_len = 1;
85	msg.msg_iov = &vec;
86	msg.msg_iovlen = 1;
87
88	pfd.fd = sock;
89	pfd.events = POLLOUT;
90	while ((n = sendmsg(sock, &msg, 0)) == -1 &&
91	    (errno == EAGAIN || errno == EINTR)) {
92		debug3("%s: sendmsg(%d): %s", __func__, fd, strerror(errno));
93		(void)poll(&pfd, 1, -1);
94	}
95	if (n == -1) {
96		error("%s: sendmsg(%d): %s", __func__, fd,
97		    strerror(errno));
98		return -1;
99	}
100
101	if (n != 1) {
102		error("%s: sendmsg: expected sent 1 got %ld",
103		    __func__, (long)n);
104		return -1;
105	}
106	return 0;
107#else
108	error("%s: file descriptor passing not supported", __func__);
109	return -1;
110#endif
111}
112
113int
114mm_receive_fd(int sock)
115{
116#if defined(HAVE_RECVMSG) && (defined(HAVE_ACCRIGHTS_IN_MSGHDR) || defined(HAVE_CONTROL_IN_MSGHDR))
117	struct msghdr msg;
118#ifndef HAVE_ACCRIGHTS_IN_MSGHDR
119	union {
120		struct cmsghdr hdr;
121		char buf[CMSG_SPACE(sizeof(int))];
122	} cmsgbuf;
123	struct cmsghdr *cmsg;
124#endif
125	struct iovec vec;
126	ssize_t n;
127	char ch;
128	int fd;
129	struct pollfd pfd;
130
131	memset(&msg, 0, sizeof(msg));
132	vec.iov_base = &ch;
133	vec.iov_len = 1;
134	msg.msg_iov = &vec;
135	msg.msg_iovlen = 1;
136#ifdef HAVE_ACCRIGHTS_IN_MSGHDR
137	msg.msg_accrights = (caddr_t)&fd;
138	msg.msg_accrightslen = sizeof(fd);
139#else
140	memset(&cmsgbuf, 0, sizeof(cmsgbuf));
141	msg.msg_control = &cmsgbuf.buf;
142	msg.msg_controllen = sizeof(cmsgbuf.buf);
143#endif
144
145	pfd.fd = sock;
146	pfd.events = POLLIN;
147	while ((n = recvmsg(sock, &msg, 0)) == -1 &&
148	    (errno == EAGAIN || errno == EINTR)) {
149		debug3("%s: recvmsg: %s", __func__, strerror(errno));
150		(void)poll(&pfd, 1, -1);
151	}
152	if (n == -1) {
153		error("%s: recvmsg: %s", __func__, strerror(errno));
154		return -1;
155	}
156
157	if (n != 1) {
158		error("%s: recvmsg: expected received 1 got %ld",
159		    __func__, (long)n);
160		return -1;
161	}
162
163#ifdef HAVE_ACCRIGHTS_IN_MSGHDR
164	if (msg.msg_accrightslen != sizeof(fd)) {
165		error("%s: no fd", __func__);
166		return -1;
167	}
168#else
169	cmsg = CMSG_FIRSTHDR(&msg);
170	if (cmsg == NULL) {
171		error("%s: no message header", __func__);
172		return -1;
173	}
174
175#ifndef BROKEN_CMSG_TYPE
176	if (cmsg->cmsg_type != SCM_RIGHTS) {
177		error("%s: expected type %d got %d", __func__,
178		    SCM_RIGHTS, cmsg->cmsg_type);
179		return -1;
180	}
181#endif
182	fd = (*(int *)CMSG_DATA(cmsg));
183#endif
184	return fd;
185#else
186	error("%s: file descriptor passing not supported", __func__);
187	return -1;
188#endif
189}
190