1 /* $OpenBSD: monitor_fdpass.c,v 1.7 2016/02/29 20:22:36 jca Exp $ */
2
3 /*
4 * Copyright (c) 2002 Matthieu Herrb
5 * Copyright (c) 2001 Niels Provos <provos@citi.umich.edu>
6 *
7 * Permission to use, copy, modify, and distribute this software for any
8 * purpose with or without fee is hereby granted, provided that the above
9 * copyright notice and this permission notice appear in all copies.
10 *
11 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
12 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
13 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
14 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
15 * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
16 * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
17 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18 */
19
20 #include <sys/types.h>
21 #include <sys/socket.h>
22 #include <sys/uio.h>
23
24 #include <errno.h>
25 #include <fcntl.h>
26 #include <string.h>
27 #include <syslog.h>
28 #include <unistd.h>
29 #include "monitor.h"
30
31 void
send_fd(int sock,int fd)32 send_fd(int sock, int fd)
33 {
34 struct msghdr msg;
35 union {
36 struct cmsghdr hdr;
37 char buf[CMSG_SPACE(sizeof(int))];
38 } cmsgbuf;
39 struct cmsghdr *cmsg;
40 struct iovec vec;
41 int result = 0;
42 ssize_t n;
43
44 memset(&msg, 0, sizeof(msg));
45
46 if (fd >= 0) {
47 msg.msg_control = (caddr_t)&cmsgbuf.buf;
48 msg.msg_controllen = sizeof(cmsgbuf.buf);
49 cmsg = CMSG_FIRSTHDR(&msg);
50 cmsg->cmsg_len = CMSG_LEN(sizeof(int));
51 cmsg->cmsg_level = SOL_SOCKET;
52 cmsg->cmsg_type = SCM_RIGHTS;
53 *(int *)CMSG_DATA(cmsg) = fd;
54 } else
55 result = errno;
56
57 vec.iov_base = &result;
58 vec.iov_len = sizeof(int);
59 msg.msg_iov = &vec;
60 msg.msg_iovlen = 1;
61
62 if ((n = sendmsg(sock, &msg, 0)) == -1)
63 syslog(LOG_WARNING, "send_fd: sendmsg(%d): %m", sock);
64 if (n != sizeof(int))
65 syslog(LOG_WARNING, "send_fd: sendmsg: expected sent 1 got %zd",
66 n);
67 }
68
69 int
recv_fd(int sock)70 recv_fd(int sock)
71 {
72 struct msghdr msg;
73 union {
74 struct cmsghdr hdr;
75 char buf[CMSG_SPACE(sizeof(int))];
76 } cmsgbuf;
77 struct cmsghdr *cmsg;
78 struct iovec vec;
79 ssize_t n;
80 int result;
81 int fd;
82
83 memset(&msg, 0, sizeof(msg));
84 vec.iov_base = &result;
85 vec.iov_len = sizeof(int);
86 msg.msg_iov = &vec;
87 msg.msg_iovlen = 1;
88 msg.msg_control = &cmsgbuf.buf;
89 msg.msg_controllen = sizeof(cmsgbuf.buf);
90
91 if ((n = recvmsg(sock, &msg, 0)) == -1) {
92 syslog(LOG_WARNING, "recv_fd: recvmsg(%d): %m", sock);
93 return -1;
94 }
95 if (n != sizeof(int))
96 syslog(LOG_WARNING,
97 "recv_fd: recvmsg: expected received 1 got %zd", n);
98 if (result == 0) {
99 cmsg = CMSG_FIRSTHDR(&msg);
100 if (cmsg == NULL) {
101 syslog(LOG_WARNING, "recv_fd: no message header");
102 return (-1);
103 }
104 if (cmsg->cmsg_type != SCM_RIGHTS)
105 syslog(LOG_WARNING, "recv_fd: expected type %d got %d",
106 SCM_RIGHTS, cmsg->cmsg_type);
107 fd = (*(int *)CMSG_DATA(cmsg));
108 return (fd);
109 } else {
110 errno = result;
111 return (-1);
112 }
113 }
114