1 /* $OpenBSD: monitor_fdpass.c,v 1.17 2016/02/29 20:22:36 jca Exp $ */
2
3 /*
4 * Copyright 2001 Niels Provos <provos@citi.umich.edu>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28 #include <sys/types.h>
29 #include <sys/socket.h>
30 #include <sys/uio.h>
31
32 #include <errno.h>
33 #include <string.h>
34
35 #include "log.h"
36 #include "monitor.h"
37
38 int
mm_send_fd(int socket,int fd)39 mm_send_fd(int socket, int fd)
40 {
41 struct msghdr msg;
42 union {
43 struct cmsghdr hdr;
44 char buf[CMSG_SPACE(sizeof(int))];
45 } cmsgbuf;
46 char ch = '\0';
47 struct cmsghdr *cmsg;
48 struct iovec vec;
49 ssize_t n;
50
51 bzero(&msg, sizeof msg);
52 msg.msg_control = (caddr_t)&cmsgbuf.buf;
53 msg.msg_controllen = sizeof(cmsgbuf.buf);
54 cmsg = CMSG_FIRSTHDR(&msg);
55 cmsg->cmsg_len = CMSG_LEN(sizeof(int));
56 cmsg->cmsg_level = SOL_SOCKET;
57 cmsg->cmsg_type = SCM_RIGHTS;
58 *(int *)CMSG_DATA(cmsg) = fd;
59
60 vec.iov_base = &ch;
61 vec.iov_len = 1;
62 msg.msg_iov = &vec;
63 msg.msg_iovlen = 1;
64
65 if ((n = sendmsg(socket, &msg, 0)) == -1) {
66 log_error("mm_send_fd: sendmsg(%d)", fd);
67 return -1;
68 }
69 if (n != 1) {
70 log_error("mm_send_fd: sendmsg: expected sent 1 got %zd", n);
71 return -1;
72 }
73 return 0;
74 }
75
76 int
mm_receive_fd(int socket)77 mm_receive_fd(int socket)
78 {
79 struct msghdr msg;
80 union {
81 struct cmsghdr hdr;
82 char buf[CMSG_SPACE(sizeof(int))];
83 } cmsgbuf;
84 char ch;
85 struct cmsghdr *cmsg;
86 struct iovec vec;
87 ssize_t n;
88 int fd;
89
90 bzero(&msg, sizeof msg);
91 vec.iov_base = &ch;
92 vec.iov_len = 1;
93 msg.msg_iov = &vec;
94 msg.msg_iovlen = 1;
95 msg.msg_control = &cmsgbuf.buf;
96 msg.msg_controllen = sizeof(cmsgbuf.buf);
97
98 if ((n = recvmsg(socket, &msg, 0)) == -1) {
99 log_error("mm_receive_fd: recvmsg");
100 return -1;
101 }
102 if (n != 1) {
103 log_error("mm_receive_fd: recvmsg: expected received 1 got %zd",
104 n);
105 return -1;
106 }
107 cmsg = CMSG_FIRSTHDR(&msg);
108 if (cmsg == NULL) {
109 log_error("mm_receive_fd: no message header");
110 return -1;
111 }
112 if (cmsg->cmsg_type != SCM_RIGHTS) {
113 log_error("mm_receive_fd: expected type %d got %d", SCM_RIGHTS,
114 cmsg->cmsg_type);
115 return -1;
116 }
117 fd = (*(int *)CMSG_DATA(cmsg));
118 return fd;
119 }
120