1 /* $OpenBSD: monitor_fdpass.c,v 1.1 2004/11/28 18:49:30 henning 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
30 void
send_fd(int sock,int fd)31 send_fd(int sock, int fd)
32 {
33 struct msghdr msg;
34 char tmp[CMSG_SPACE(sizeof(int))];
35 struct cmsghdr *cmsg;
36 struct iovec vec;
37 int result = 0;
38 ssize_t n;
39
40 memset(&msg, 0, sizeof(msg));
41
42 if (fd >= 0) {
43 msg.msg_control = (caddr_t)tmp;
44 msg.msg_controllen = CMSG_LEN(sizeof(int));
45 cmsg = CMSG_FIRSTHDR(&msg);
46 cmsg->cmsg_len = CMSG_LEN(sizeof(int));
47 cmsg->cmsg_level = SOL_SOCKET;
48 cmsg->cmsg_type = SCM_RIGHTS;
49 *(int *)CMSG_DATA(cmsg) = fd;
50 } else
51 result = errno;
52
53 vec.iov_base = &result;
54 vec.iov_len = sizeof(int);
55 msg.msg_iov = &vec;
56 msg.msg_iovlen = 1;
57
58 if ((n = sendmsg(sock, &msg, 0)) == -1)
59 syslog(LOG_WARNING, "send_fd: sendmsg(%d): %m", sock);
60 if (n != sizeof(int))
61 syslog(LOG_WARNING, "send_fd: sendmsg: expected sent 1 got %ld",
62 (long)n);
63 }
64
65 int
recv_fd(int sock)66 recv_fd(int sock)
67 {
68 struct msghdr msg;
69 char tmp[CMSG_SPACE(sizeof(int))];
70 struct cmsghdr *cmsg;
71 struct iovec vec;
72 ssize_t n;
73 int result;
74 int fd;
75
76 memset(&msg, 0, sizeof(msg));
77 vec.iov_base = &result;
78 vec.iov_len = sizeof(int);
79 msg.msg_iov = &vec;
80 msg.msg_iovlen = 1;
81 msg.msg_control = tmp;
82 msg.msg_controllen = sizeof(tmp);
83
84 if ((n = recvmsg(sock, &msg, 0)) == -1)
85 syslog(LOG_WARNING, "recv_fd: recvmsg(%d): %m", sock);
86 if (n != sizeof(int))
87 syslog(LOG_WARNING,
88 "recv_fd: recvmsg: expected received 1 got %ld", (long)n);
89 if (result == 0) {
90 cmsg = CMSG_FIRSTHDR(&msg);
91 if (cmsg == NULL) {
92 syslog(LOG_WARNING, "recv_fd: no message header");
93 return (-1);
94 }
95 if (cmsg->cmsg_type != SCM_RIGHTS)
96 syslog(LOG_WARNING, "recv_fd: expected type %d got %d",
97 SCM_RIGHTS, cmsg->cmsg_type);
98 fd = (*(int *)CMSG_DATA(cmsg));
99 return (fd);
100 } else {
101 errno = result;
102 return (-1);
103 }
104 }
105