1 #include <err.h>
2 #include <fcntl.h>
3 #include <stdlib.h>
4 #include <unistd.h>
5
6 #include <sys/event.h>
7 #include <sys/time.h>
8
9 /*
10 * External test set-up code is expected to do the equivalent of
11 * cd $TOPDIR
12 * mkdir realdir
13 * mkdir nulldir
14 * mount -t null $TOPDIR/realdir $TOPDIR/nulldir
15 * rm -f $TOPDIR/realdir/afile
16 * touch $TOPDIR/realdir/afile
17 * then execute this test program:
18 * ./h_nullmnt $TOPDIR/realdir/afile $TOPDIR/nulldir/afile
19 *
20 * The expected result is that the write() to the nullfile will
21 * queue up a preexisting kevent which will then be detected by
22 * the (second) call to kevent(); the failure mode is that the
23 * write()'s extension to the file is not seen, and the kevent
24 * call times out after 5 seconds.
25 *
26 * Clean-up code should undo the null mount and delete everything
27 * in the test directory.
28 */
29
main(int argc,char ** argv)30 int main(int argc, char **argv)
31 {
32 int watch_file, write_file;
33 int kq, nev, rsize;
34 struct timespec timeout;
35 struct kevent eventlist;
36 const char outbuf[] = "new\n";
37 char inbuf[20];
38
39 if (argc <= 2)
40 errx(EXIT_FAILURE, "insufficient args %d", argc);
41
42 watch_file = open(argv[1], O_RDONLY);
43 if (watch_file == -1)
44 err(EXIT_FAILURE, "failed to open watch_file %s",
45 argv[1]);
46
47 write_file = open(argv[2], O_WRONLY, O_APPEND);
48 if (write_file == -1)
49 err(EXIT_FAILURE, "failed to open write_file %s",
50 argv[2]);
51
52 if ((kq = kqueue()) == -1)
53 err(EXIT_FAILURE, "Cannot create kqueue");
54
55 timeout.tv_sec = 5;
56 timeout.tv_nsec = 0;
57
58 EV_SET(&eventlist, watch_file,
59 EVFILT_VNODE, EV_ADD | EV_ENABLE | EV_CLEAR,
60 NOTE_WRITE | NOTE_EXTEND, 0, 0);
61 if (kevent(kq, &eventlist, 1, NULL, 0, NULL) == -1)
62 err(EXIT_FAILURE, "Failed to set eventlist for fd %d",
63 watch_file);
64
65 rsize = read(watch_file, &inbuf, sizeof(inbuf));
66 if (rsize)
67 errx(EXIT_FAILURE, "Ooops we got %d bytes of data!\n", rsize);
68
69 write(write_file, &outbuf, sizeof(outbuf) - 1);
70
71 nev = kevent(kq, NULL, 0, &eventlist, 1, &timeout);
72 if (nev == -1)
73 err(EXIT_FAILURE, "Failed to retrieve event");
74
75 errx((nev == 0) ? EXIT_FAILURE : EXIT_SUCCESS,
76 "Retrieved %d events, first 0x%x", nev, eventlist.flags);
77 }
78