memcheck/tests/freebsd/eventfd2.c

   1 /* EFD_SEMAPHORE */
   2
   3 #include <sys/eventfd.h>
   4 #include <sys/wait.h>
   5 #include <inttypes.h>
   6 #include <stdlib.h>
   7 #include <stdio.h>
   8 #include <unistd.h>
   9
  10 static void xsem_wait(int fd)
  11 {
  12    eventfd_t cntr;
  13
  14    if (eventfd_read(fd, &cntr) != 0) {
  15       perror("reading eventfd");
  16       exit(1);
  17    }
  18
  19    fprintf(stderr, "fd %d wait completed: count=%" PRIu64 "\n",
  20            fd, cntr);
  21 }
  22
  23 static void xsem_post(int fd, int count)
  24 {
  25    eventfd_t cntr = count;
  26
  27    if (eventfd_write(fd, cntr) != 0) {
  28       perror("writing eventfd");
  29       exit(1);
  30    }
  31 }
  32
  33 static void sem_player(int fd1, int fd2)
  34 {
  35    /* these printfs did contain the pid
  36     * so "[%u] ... ", getpid()
  37     * not good for regresson tests
  38     * (also xsem_wait above)
  39     */
  40    fprintf(stderr, "fd %d posting 1\n", fd1);
  41    xsem_post(fd1, 1);
  42
  43    fprintf(stderr, "fd %d waiting\n", fd2);
  44    xsem_wait(fd2);
  45
  46    fprintf(stderr, "fd %d posting 1\n", fd1);
  47    xsem_post(fd1, 1);
  48
  49    fprintf(stderr, "fd %d waiting\n", fd2);
  50    xsem_wait(fd2);
  51
  52    fprintf(stderr, "fd %d posting 5\n", fd1);
  53    xsem_post(fd1, 5);
  54
  55    fprintf(stderr, "fd %d waiting 5 times\n", fd2);
  56    xsem_wait(fd2);
  57    xsem_wait(fd2);
  58    xsem_wait(fd2);
  59    xsem_wait(fd2);
  60    xsem_wait(fd2);
  61 }
  62
  63 static void usage(char const *prg)
  64 {
  65    fprintf(stderr, "use: %s [-h]\n", prg);
  66 }
  67
  68 int main(int argc, char **argv)
  69 {
  70    int c, fd1, fd2, status;
  71    pid_t cpid_poster, cpid_waiter;
  72
  73    while ((c = getopt(argc, argv, "h")) != -1) {
  74
  75       switch (c) {
  76       default:
  77          usage(argv[0]);
  78          return 1;
  79       }
  80    }
  81
  82    if ((fd1 = eventfd(0, EFD_SEMAPHORE)) == -1 ||
  83        (fd2 = eventfd(0, EFD_SEMAPHORE)) == -1) {
  84       perror("eventfd");
  85       return 1;
  86    }
  87    if ((cpid_poster = fork()) == 0) {
  88       sem_player(fd1, fd2);
  89       exit(0);
  90    }
  91    sleep(1);
  92    if ((cpid_waiter = fork()) == 0) {
  93       sem_player(fd2, fd1);
  94       exit(0);
  95    }
  96    waitpid(cpid_poster, &status, 0);
  97    waitpid(cpid_waiter, &status, 0);
  98
  99    exit(0);
 100 }