/* Tests for POSIX timer implementation using another process's CPU clock.  */

#include <unistd.h>

#if _POSIX_THREADS && defined _POSIX_CPUTIME

#include <errno.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <fcntl.h>

#include <time.h>

#include <signal.h>

#include <sys/wait.h>

static clockid_t child_clock;

#define TEST_CLOCK child_clock

#define TEST_CLOCK_MISSING(clock) \

  (setup_test () ? "other-process CPU clock timer support" : NULL)

/* This function is intended to rack up both user and system time.  */

static void

chew_cpu (void)

{

  while (1)

    {

      static volatile char buf[4096];

      for (int i = 0; i < 100; ++i)

	for (size_t j = 0; j < sizeof buf; ++j)

	  buf[j] = 0xaa;

      int nullfd = open ("/dev/null", O_WRONLY);

      for (int i = 0; i < 100; ++i)

	for (size_t j = 0; j < sizeof buf; ++j)

	  buf[j] = 0xbb;

      write (nullfd, (char *) buf, sizeof buf);

      close (nullfd);

      if (getppid () == 1)

	_exit (2);

    }

}

static pid_t child;

static void

cleanup_child (void)

{

  if (child <= 0)

    return;

  if (kill (child, SIGKILL) < 0 && errno != ESRCH)

    printf ("cannot kill child %d: %m\n", child);

  else

    {

      int status;

      errno = 0;

      if (waitpid (child, &status, 0) != child)

	printf ("waitpid %d: %m\n", child);

    }

}

#define CLEANUP_HANDLER cleanup_child ()

static int

setup_test (void)

{

  /* Test timers on a process CPU clock by having a child process eating

     CPU.  First make sure we can make such timers at all.  */

  int pipefd[2];

  if (pipe (pipefd) < 0)

    {

      printf ("pipe: %m\n");

      exit (1);

    }

  child = fork ();

  if (child == 0)

    {

      char c;

      close (pipefd[1]);

      if (read (pipefd[0], &c, 1) == 1)

	chew_cpu ();

      _exit (1);

    }

  if (child < 0)

    {

      printf ("fork: %m\n");

      exit (1);

    }

  atexit (&cleanup_child);

  close (pipefd[0]);

  int e = clock_getcpuclockid (child, &child_clock);

  if (e == EPERM)

    {

      puts ("clock_getcpuclockid does not support other processes");

      return 1;

    }

  if (e != 0)

    {

      printf ("clock_getcpuclockid: %s\n", strerror (e));

      exit (1);

    }

  timer_t t;

  if (timer_create (TEST_CLOCK, NULL, &t) != 0)

    {

      printf ("timer_create: %m\n");

      return 1;

    }

  timer_delete (t);

  /* Get the child started chewing.  */

  if (write (pipefd[1], "x", 1) != 1)

    {

      printf ("write to pipe: %m\n");

      return 1;

    }

  close (pipefd[1]);

  return 0;

}

#else

# define TEST_CLOCK_MISSING(clock) "process clocks"

#endif

#include "tst-timer4.c"