memcheck/tests/freebsd/kqueuex.c

   1 #include <sys/event.h>
   2 #include <err.h>
   3 #include <fcntl.h>
   4 #include <stdio.h>
   5 #include <stdlib.h>
   6 #include <string.h>
   7 #include <unistd.h>
   8
   9 int
  10 main(int argc, char **argv)
  11 {
  12     struct kevent event;    /* Event we want to monitor */
  13     struct kevent tevent;   /* Event triggered */
  14     int kq, fd, ret;
  15
  16     if (argc != 2)
  17         err(EXIT_FAILURE, "Usage: %s path\n", argv[0]);
  18     fd = open(argv[1], O_RDONLY);
  19     if (fd == -1)
  20         err(EXIT_FAILURE, "Failed to open '%s'", argv[1]);
  21
  22     /* Create kqueue. */
  23     kq = kqueuex(KQUEUE_CLOEXEC);
  24     if (kq == -1)
  25         err(EXIT_FAILURE, "kqueuex(KQUEUE_CLOEXEC) failed");
  26
  27     /* Initialize kevent structure. */
  28     EV_SET(&event, fd, EVFILT_VNODE, EV_ADD | EV_CLEAR, NOTE_WRITE,
  29         0, NULL);
  30     /* Attach event to the kqueue. */
  31     ret = kevent(kq, &event, 1, NULL, 0, NULL);
  32     if (ret == -1)
  33         err(EXIT_FAILURE, "kevent register");
  34
  35     for (;;) {
  36         /* Sleep until something happens. */
  37         ret = kevent(kq, NULL, 0, &tevent, 1, NULL);
  38         if (ret == -1) {
  39             err(EXIT_FAILURE, "kevent wait");
  40         } else if (ret > 0) {
  41             if (tevent.flags & EV_ERROR)
  42                 errx(EXIT_FAILURE, "Event error: %s", strerror(event.data));
  43             else {
  44                 printf("Something was written in '%s'\n", argv[1]);
  45                 exit(0);
  46            }
  47         }
  48     }
  49
  50     /* kqueues are destroyed upon close() */
  51     (void)close(kq);
  52     (void)close(fd);
  53 }
  54