test/childthread.c

/* Test exit of a child of a TCB_EXITING child where the toplevel process starts
 * waiting on it.  The middle one gets detached and strace must update the
 * toplevel process'es number of attached children to 0.
 * 
 * gcc -o test/childthread test/childthread.c -Wall -ggdb2 -pthread;./strace -f ./test/childthread
 * It must print: write(1, "OK\n", ...
 */

#include <pthread.h>
#include <assert.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/wait.h>

static void *start0 (void *arg)
{
  pause ();
  /* NOTREACHED */
  assert (0);
}

int main (void)
{
  pthread_t thread0;
  int i;
  pid_t child, got_pid;
  int status;

  child = fork ();
  switch (child)
    {
    case -1:
      assert (0);
    case 0:
      i = pthread_create (&thread0, NULL, start0, NULL);
      assert (i == 0);
      /* The thread must be initialized, it becomes thread-child of this
	 process-child (child of a child of the toplevel process).  */
      sleep (1);
      /* Here the child TCB cannot be deallocated as there still exist
       * children (the thread child in START0).  */
      exit (42);
      /* NOTREACHED */
      assert (0);
    default:
      /* We must not be waiting in WAITPID when the child double-exits.  */
      sleep (2);
      /* PID must be -1.  */
      got_pid = waitpid (-1, &status, 0);
      assert (got_pid == child);
      assert (WIFEXITED (status));
      assert (WEXITSTATUS (status) == 42);
      puts ("OK");
      exit (0);
    }
  /* NOTREACHED */
  assert (0);
}