1  /* Tests for POSIX timer implementation using thread CPU clock.  */
       2  
       3  #include <unistd.h>
       4  
       5  #if _POSIX_THREADS && defined _POSIX_CPUTIME
       6  
       7  #include <errno.h>
       8  #include <stdio.h>
       9  #include <stdlib.h>
      10  #include <string.h>
      11  #include <fcntl.h>
      12  #include <time.h>
      13  #include <pthread.h>
      14  
      15  #include <support/xunistd.h>
      16  
      17  static clockid_t worker_thread_clock;
      18  
      19  #define TEST_CLOCK worker_thread_clock
      20  #define TEST_CLOCK_MISSING(clock) \
      21    (setup_test () ? "thread CPU clock timer support" : NULL)
      22  
      23  /* This function is intended to rack up both user and system time.  */
      24  static void *
      25  chew_cpu (void *arg)
      26  {
      27    while (1)
      28      {
      29        static volatile char buf[4096];
      30        for (int i = 0; i < 100; ++i)
      31  	for (size_t j = 0; j < sizeof buf; ++j)
      32  	  buf[j] = 0xaa;
      33        int nullfd = open ("/dev/null", O_WRONLY);
      34        for (int i = 0; i < 100; ++i)
      35  	for (size_t j = 0; j < sizeof buf; ++j)
      36  	  buf[j] = 0xbb;
      37        xwrite (nullfd, (char *) buf, sizeof buf);
      38        close (nullfd);
      39      }
      40  
      41    return NULL;
      42  }
      43  
      44  static int
      45  setup_test (void)
      46  {
      47    /* Test timers on a thread CPU clock by having a worker thread eating
      48       CPU.  First make sure we can make such timers at all.  */
      49  
      50    pthread_t th;
      51    int e = pthread_create (&th, NULL, chew_cpu, NULL);
      52    if (e != 0)
      53      {
      54        printf ("pthread_create: %s\n", strerror (e));
      55        exit (1);
      56      }
      57  
      58    e = pthread_getcpuclockid (th, &worker_thread_clock);
      59    if (e == EPERM || e == ENOENT || e == ENOTSUP)
      60      {
      61        puts ("pthread_getcpuclockid does not support other threads");
      62        return 1;
      63      }
      64    if (e != 0)
      65      {
      66        printf ("pthread_getcpuclockid: %s\n", strerror (e));
      67        exit (1);
      68      }
      69  
      70    timer_t t;
      71    if (timer_create (TEST_CLOCK, NULL, &t) != 0)
      72      {
      73        printf ("timer_create: %m\n");
      74        return 1;
      75      }
      76    timer_delete (t);
      77  
      78    return 0;
      79  }
      80  
      81  #else
      82  # define TEST_CLOCK_MISSING(clock) "process clocks"
      83  #endif
      84  
      85  #include "tst-timer4.c"