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glibc/rt/tst-cputimer3.c
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/* 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" |