test/unix/loopdesc/loopdesc.c

   1 #include <sys/types.h>
   2 #include <sys/socket.h>
   3 #include <sys/un.h>
   4
   5 #include <err.h>
   6 #include <stdio.h>
   7 #include <stdlib.h>
   8 #include <string.h>
   9 #include <unistd.h>
  10
  11 static void
  12 test_sendto_self(int to_s, int s)
  13 {
  14         struct msghdr msg;
  15         struct iovec iov;
  16         union {
  17                 struct cmsghdr cm;
  18                 uint8_t data[CMSG_SPACE(sizeof(int))];
  19         } ctrl;
  20         struct cmsghdr *cm;
  21         int n, buf;
  22
  23         iov.iov_base = &buf;
  24         iov.iov_len = sizeof(buf);
  25
  26         memset(&msg, 0, sizeof(msg));
  27         msg.msg_iov = &iov;
  28         msg.msg_iovlen = 1;
  29         msg.msg_control = ctrl.data;
  30         msg.msg_controllen = sizeof(ctrl.data);
  31
  32         memset(&ctrl, 0, sizeof(ctrl));
  33         cm = CMSG_FIRSTHDR(&msg);
  34         cm->cmsg_len = CMSG_LEN(sizeof(int));
  35         cm->cmsg_level = SOL_SOCKET;
  36         cm->cmsg_type = SCM_RIGHTS;
  37         *((int *)CMSG_DATA(cm)) = s;
  38
  39         n = sendmsg(to_s, &msg, 0);
  40         if (n < 0)
  41                 err(1, "sendmsg failed");
  42         else if (n != sizeof(buf))
  43                 errx(1, "sendmsg sent %d", n);
  44 }
  45
  46 static void
  47 usage(const char *cmd)
  48 {
  49         fprintf(stderr, "%s [-x]\n", cmd);
  50         exit(1);
  51 }
  52
  53 int
  54 main(int argc, char *argv[])
  55 {
  56         int s[2], opt, xref;
  57
  58         xref = 0;
  59         while ((opt = getopt(argc, argv, "x")) != -1) {
  60                 switch (opt) {
  61                 case 'x':
  62                         xref = 1;
  63                         break;
  64
  65                 default:
  66                         usage(argv[0]);
  67                 }
  68         }
  69
  70         if (socketpair(AF_LOCAL, SOCK_STREAM, 0, s) < 0)
  71                 err(1, "socketpair(LOCAL, STREAM) failed");
  72
  73         if (xref) {
  74                 fprintf(stderr, "cross reference\n");
  75                 /* Send s[0] to s[1].rcvbuf */
  76                 test_sendto_self(s[0], s[0]);
  77                 /* Send s[1] to s[0].rcvbuf */
  78                 test_sendto_self(s[1], s[1]);
  79         } else {
  80                 fprintf(stderr, "self reference\n");
  81                 /* Send s[0] to s[0].rcvbuf */
  82                 test_sendto_self(s[1], s[0]);
  83                 /* Send s[1] to s[1].rcvbuf */
  84                 test_sendto_self(s[0], s[1]);
  85         }
  86         exit(0);
  87 }