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glibc  2.9
Defines | Functions
tst-rwlock12.c File Reference
#include <errno.h>
#include <pthread.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/wait.h>
#include "../test-skeleton.c"

Go to the source code of this file.

Defines

#define TEST_FUNCTION   do_test ()

Functions

static int do_test (void)

Define Documentation

#define TEST_FUNCTION   do_test ()

Definition at line 207 of file tst-rwlock12.c.


Function Documentation

static int do_test ( void  ) [static]

Definition at line 32 of file tst-rwlock12.c.

{
  size_t ps = sysconf (_SC_PAGESIZE);
  char tmpfname[] = "/tmp/tst-rwlock12.XXXXXX";
  char data[ps];
  void *mem;
  int fd;
  pthread_mutex_t *m;
  pthread_mutexattr_t ma;
  pthread_rwlock_t *r;
  pthread_rwlockattr_t ra;
  pid_t pid;
  int status = 0;

  fd = mkstemp (tmpfname);
  if (fd == -1)
    {
      printf ("cannot open temporary file: %m\n");
      return 1;
    }

  /* Make sure it is always removed.  */
  unlink (tmpfname);

  /* Create one page of data.  */
  memset (data, '\0', ps);

  /* Write the data to the file.  */
  if (write (fd, data, ps) != (ssize_t) ps)
    {
      puts ("short write");
      return 1;
    }

  mem = mmap (NULL, ps, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
  if (mem == MAP_FAILED)
    {
      printf ("mmap failed: %m\n");
      return 1;
    }

  r = (pthread_rwlock_t *) (((uintptr_t) mem + __alignof (pthread_rwlock_t))
                         & ~(__alignof (pthread_rwlock_t) - 1));
  /* The following assumes alignment for a mutex is at least as high
     as that for a rwlock.  Which is true in our case.  */
  m = (pthread_mutex_t *) (r + 1);

  if (pthread_rwlockattr_init (&ra) != 0)
    {
      puts ("rwlockattr_init failed");
      return 1;
    }

  if (pthread_rwlockattr_setpshared (&ra, PTHREAD_PROCESS_SHARED) != 0)
    {
      puts ("rwlockattr_setpshared failed");
      return 1;
    }

  if (pthread_rwlock_init (r, &ra) != 0)
    {
      puts ("rwlock_init failed");
      return 1;
    }

  if (pthread_mutexattr_init (&ma) != 0)
    {
      puts ("rwlockattr_init failed");
      return 1;
    }

  if (pthread_mutexattr_setpshared (&ma, PTHREAD_PROCESS_SHARED) != 0)
    {
      puts ("mutexattr_setpshared failed");
      return 1;
    }

  if (pthread_mutex_init (m, &ma) != 0)
    {
      puts ("mutex_init failed");
      return 1;
    }

  /* Lock the mutex.  */
  if (pthread_mutex_lock (m) != 0)
    {
      puts ("mutex_lock failed");
      return 1;
    }

  puts ("going to fork now");
  pid = fork ();
  if (pid == -1)
    {
      puts ("fork failed");
      return 1;
    }
  else if (pid == 0)
    {
      /* Lock the mutex.  */
      if (pthread_mutex_lock (m) != 0)
       {
         puts ("child: mutex_lock failed");
         return 1;
       }

      /* Try to get the rwlock.  */
      if (pthread_rwlock_trywrlock (r) == 0)
       {
         puts ("rwlock_trywrlock succeeded");
         return 1;
       }

      /* Try again.  */
      struct timespec ts = { .tv_sec = 0, .tv_nsec = 500000000 };
      int e = pthread_rwlock_timedwrlock (r, &ts);
      if (e == 0)
       {
         puts ("rwlock_timedwrlock succeeded");
         return 1;
       }
      if (e != ETIMEDOUT)
       {
         puts ("rwlock_timedwrlock didn't return ETIMEDOUT");
         status = 1;
       }

      if (pthread_rwlock_tryrdlock (r) == 0)
       {
         puts ("rwlock_tryrdlock succeeded");
         return 1;
       }

      e = pthread_rwlock_timedrdlock (r, &ts);
      if (e == 0)
       {
         puts ("rwlock_timedrdlock succeeded");
         return 1;
       }
      if (e != ETIMEDOUT)
       {
         puts ("rwlock_timedrdlock didn't return ETIMEDOUT");
         status = 1;
       }
    }
  else
    {
      /* Lock the rwlock for writing.  */
      if (pthread_rwlock_wrlock (r) != 0)
       {
         puts ("rwlock_wrlock failed");
         kill (pid, SIGTERM);
         return 1;
       }

      /* Allow the child to run.  */
      if (pthread_mutex_unlock (m) != 0)
       {
         puts ("mutex_unlock failed");
         kill (pid, SIGTERM);
         return 1;
       }

      /* Just wait for the child.  */
      if (TEMP_FAILURE_RETRY (waitpid (pid, &status, 0)) != pid)
       {
         puts ("waitpid failed");
         kill (pid, SIGTERM);
         return 1;
       }
    }

  return status;
}

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