1 #include <u.h>
2 #define NOPLAN9DEFINES
3 #include <libc.h>
4 #include <sys/socket.h>
5 #include <sys/uio.h>
6 #include <unistd.h>
7 #include <errno.h>
8 
9 typedef struct Sendfd Sendfd;
10 struct Sendfd {
11 	struct cmsghdr cmsg;
12 	int fd;
13 };
14 
15 int
16 sendfd(int s, int fd)
17 {
18 	char buf[1];
19 	struct iovec iov;
20 	struct msghdr msg;
21 	int n;
22 	Sendfd sfd;
23 
24 	buf[0] = 0;
25 	iov.iov_base = buf;
26 	iov.iov_len = 1;
27 
28 	memset(&msg, 0, sizeof msg);
29 	msg.msg_iov = &iov;
30 	msg.msg_iovlen = 1;
31 
32 	sfd.cmsg.cmsg_len = sizeof sfd;
33 	sfd.cmsg.cmsg_level = SOL_SOCKET;
34 	sfd.cmsg.cmsg_type = SCM_RIGHTS;
35 	sfd.fd = fd;
36 
37 	msg.msg_control = (caddr_t)&sfd;
38 	msg.msg_controllen = sizeof sfd;
39 
40 	if((n=sendmsg(s, &msg, 0)) != iov.iov_len)
41 		return -1;
42 	return 0;
43 }
44 
45 int
46 recvfd(int s)
47 {
48 	int n;
49 	char buf[1];
50 	struct iovec iov;
51 	struct msghdr msg;
52 	Sendfd sfd;
53 
54 	iov.iov_base = buf;
55 	iov.iov_len = 1;
56 
57 	memset(&msg, 0, sizeof msg);
58 	msg.msg_name = 0;
59 	msg.msg_namelen = 0;
60 	msg.msg_iov = &iov;
61 	msg.msg_iovlen = 1;
62 
63 	memset(&sfd, 0, sizeof sfd);
64 	sfd.fd = -1;
65 	sfd.cmsg.cmsg_len = sizeof sfd;
66 	sfd.cmsg.cmsg_level = SOL_SOCKET;
67 	sfd.cmsg.cmsg_type = SCM_RIGHTS;
68 
69 	msg.msg_control = (caddr_t)&sfd;
70 	msg.msg_controllen = sizeof sfd;
71 
72 	if((n=recvmsg(s, &msg, 0)) < 0)
73 		return -1;
74 	if(n==0 && sfd.fd==-1){
75 		werrstr("eof in recvfd");
76 		return -1;
77 	}
78 	return sfd.fd;
79 }