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(stdout, "wait completed on %d: count=%" PRIu64 "\n",
  20            fd, cntr);
  21    fflush(stdout);
  22 }
  23
  24 static void xsem_post(int fd, int count)
  25 {
  26    eventfd_t cntr = count;
  27
  28    if (eventfd_write(fd, cntr) != 0) {
  29       perror("writing eventfd");
  30       exit(1);
  31    }
  32 }
  33
  34 static void sem_player(int fd1, int fd2)
  35 {
  36    /* these printfs did contain the pid
  37     * so "[%u] ... ", getpid()
  38     * not good for regresson tests
  39     * (also xsem_wait above)
  40     */
  41    fprintf(stdout, "posting 1 on %d\n", fd1);
  42    fflush(stdout);
  43    xsem_post(fd1, 1);
  44
  45    fprintf(stdout, "waiting on %d\n", fd2);
  46    fflush(stdout);
  47    xsem_wait(fd2);
  48
  49    fprintf(stdout, "posting 1 on %d\n", fd1);
  50    fflush(stdout);
  51    xsem_post(fd1, 1);
  52
  53    fprintf(stdout, "waiting on %d\n", fd2);
  54    fflush(stdout);
  55    xsem_wait(fd2);
  56
  57    fprintf(stdout, "posting 5 on %d\n", fd1);
  58    fflush(stdout);
  59    xsem_post(fd1, 5);
  60
  61    fprintf(stdout, "waiting 5 times on %d\n", fd2);
  62    fflush(stdout);
  63    xsem_wait(fd2);
  64    xsem_wait(fd2);
  65    xsem_wait(fd2);
  66    xsem_wait(fd2);
  67    xsem_wait(fd2);
  68 }
  69
  70 static void usage(char const *prg)
  71 {
  72    fprintf(stderr, "use: %s [-h]\n", prg);
  73 }
  74
  75 int main(int argc, char **argv)
  76 {
  77    int c, fd1, fd2, status;
  78    pid_t cpid_poster, cpid_waiter;
  79
  80    while ((c = getopt(argc, argv, "h")) != -1) {
  81
  82       switch (c) {
  83       default:
  84          usage(argv[0]);
  85          return 1;
  86       }
  87    }
  88
  89    if ((fd1 = eventfd(0, EFD_SEMAPHORE)) == -1 ||
  90        (fd2 = eventfd(0, EFD_SEMAPHORE)) == -1) {
  91       perror("eventfd");
  92       return 1;
  93    }
  94    if ((cpid_poster = fork()) == 0) {
  95       sem_player(fd1, fd2);
  96       exit(0);
  97    }
  98    sleep(1);
  99    if ((cpid_waiter = fork()) == 0) {
 100       sem_player(fd2, fd1);
 101       exit(0);
 102    }
 103    waitpid(cpid_poster, &status, 0);
 104    waitpid(cpid_waiter, &status, 0);
 105
 106    exit(0);
 107 }