glibc/rt/tst-cputimer3.c

131 lines
2.5 KiB
C

/* 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"