1 #include <assert.h>
2 #include <string.h>
3 #include <stdlib.h>
4 #include <unistd.h>
5 #include <errno.h>
6 #include <fcntl.h>
7 #include <sys/socket.h>
8 #include <sys/wait.h>
9 
main(int ac,const char ** av)10 int main(int ac, const char **av)
11 {
12 	int i;
13 	int data = 0;
14 	struct iovec iov = {
15 		.iov_base = &data,
16 		.iov_len = sizeof(iov)
17 	};
18 
19 	while ((i = open("/dev/null", O_RDWR)) < 3)
20 		assert(i >= 0);
21 	(void) close(3);
22 
23 	int sv[2];
24 	assert(socketpair(AF_UNIX, SOCK_STREAM, 0, sv) == 0);
25 	int one = 1;
26 	assert(setsockopt(sv[0], SOL_SOCKET, SO_PASSCRED, &one, sizeof(one)) == 0);
27 
28 	pid_t pid = fork();
29 	assert(pid >= 0);
30 
31 	if (pid) {
32 		assert(close(sv[0]) == 0);
33 		assert(dup2(sv[1], 1) == 1);
34 		assert(close(sv[1]) == 0);
35 
36 		int fds[ac];
37 		assert((fds[0] = open("/dev/null", O_RDWR)) == 3);
38 		for (i = 1; i < ac; ++i)
39 			assert((fds[i] = open(av[i], O_RDONLY)) == i + 3);
40 
41 		union {
42 			struct cmsghdr cmsg;
43 			char buf[CMSG_LEN(sizeof(fds))];
44 		} control;
45 
46 		control.cmsg.cmsg_level = SOL_SOCKET;
47 		control.cmsg.cmsg_type = SCM_RIGHTS;
48 		control.cmsg.cmsg_len = CMSG_LEN(sizeof(fds));
49 		memcpy(CMSG_DATA(&control.cmsg), fds, sizeof(fds));
50 
51 		struct msghdr mh = {
52 			.msg_iov = &iov,
53 			.msg_iovlen = 1,
54 			.msg_control = &control,
55 			.msg_controllen = sizeof(control)
56 		};
57 
58 		assert(sendmsg(1, &mh, 0) == sizeof(iov));
59 		assert(close(1) == 0);
60 
61                 int status;
62 		assert(waitpid(pid, &status, 0) == pid);
63 		assert(status == 0);
64 	} else {
65 		assert(close(sv[1]) == 0);
66 		assert(dup2(sv[0], 0) == 0);
67 		assert(close(sv[0]) == 0);
68 
69 		struct cmsghdr control[4 + ac * sizeof(int) / sizeof(struct cmsghdr)];
70 
71 		struct msghdr mh = {
72 			.msg_iov = &iov,
73 			.msg_iovlen = 1,
74 			.msg_control = control,
75 			.msg_controllen = sizeof(control)
76 		};
77 
78 		assert(recvmsg(0, &mh, 0) == sizeof(iov));
79 		assert(close(0) == 0);
80 	}
81 
82 	return 0;
83 }
84