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 #ifndef CMSG_ALIGN
10 #	ifdef __sun__
11 #		define CMSG_ALIGN _CMSG_DATA_ALIGN
12 #	else
13 #		define CMSG_ALIGN(len) (((len)+sizeof(long)-1) & ~(sizeof(long)-1))
14 #	endif
15 #endif
16 
17 #ifndef CMSG_SPACE
18 #	define CMSG_SPACE(len) (CMSG_ALIGN(sizeof(struct cmsghdr))+CMSG_ALIGN(len))
19 #endif
20 
21 #ifndef CMSG_LEN
22 #	define CMSG_LEN(len) (CMSG_ALIGN(sizeof(struct cmsghdr))+(len))
23 #endif
24 
25 int
26 sendfd(int s, int fd)
27 {
28 	char buf[1];
29 	struct iovec iov;
30 	struct msghdr msg;
31 	struct cmsghdr *cmsg;
32 	int n;
33 	char cms[CMSG_SPACE(sizeof(int))];
34 
35 	buf[0] = 0;
36 	iov.iov_base = buf;
37 	iov.iov_len = 1;
38 
39 	memset(&msg, 0, sizeof msg);
40 	msg.msg_iov = &iov;
41 	msg.msg_iovlen = 1;
42 	msg.msg_control = (caddr_t)cms;
43 	msg.msg_controllen = CMSG_LEN(sizeof(int));
44 
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 	memmove(CMSG_DATA(cmsg), &fd, sizeof(int));
50 
51 	if((n=sendmsg(s, &msg, 0)) != iov.iov_len)
52 		return -1;
53 	return 0;
54 }
55 
56 int
57 recvfd(int s)
58 {
59 	int n;
60 	int fd;
61 	char buf[1];
62 	struct iovec iov;
63 	struct msghdr msg;
64 	struct cmsghdr *cmsg;
65 	char cms[CMSG_SPACE(sizeof(int))];
66 
67 	iov.iov_base = buf;
68 	iov.iov_len = 1;
69 
70 	memset(&msg, 0, sizeof msg);
71 	msg.msg_name = 0;
72 	msg.msg_namelen = 0;
73 	msg.msg_iov = &iov;
74 	msg.msg_iovlen = 1;
75 
76 	msg.msg_control = (caddr_t)cms;
77 	msg.msg_controllen = sizeof cms;
78 
79 	if((n=recvmsg(s, &msg, 0)) < 0)
80 		return -1;
81 	if(n == 0){
82 		werrstr("unexpected EOF");
83 		return -1;
84 	}
85 	cmsg = CMSG_FIRSTHDR(&msg);
86 	memmove(&fd, CMSG_DATA(cmsg), sizeof(int));
87 	return fd;
88 }