1 /* $OpenBSD: monitor_fdpass.c,v 1.21 2016/02/29 20:22:36 jca 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
51 int
mm_send_fd(int sock,int fd)52 mm_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 %zd", __func__, 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
112 int
mm_receive_fd(int sock)113 mm_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 memset(&cmsgbuf, 0, sizeof(cmsgbuf));
140 msg.msg_control = &cmsgbuf.buf;
141 msg.msg_controllen = sizeof(cmsgbuf.buf);
142 #endif
143
144 pfd.fd = sock;
145 pfd.events = POLLIN;
146 while ((n = recvmsg(sock, &msg, 0)) == -1 &&
147 (errno == EAGAIN || errno == EINTR)) {
148 debug3("%s: recvmsg: %s", __func__, strerror(errno));
149 (void)poll(&pfd, 1, -1);
150 }
151 if (n == -1) {
152 error("%s: recvmsg: %s", __func__, strerror(errno));
153 return -1;
154 }
155
156 if (n != 1) {
157 error("%s: recvmsg: expected received 1 got %zd", __func__, 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