glibc/sysdeps/unix/sysv/linux/clock_getcpuclockid.c

50 lines
1.7 KiB
C

/* clock_getcpuclockid -- Get a clockid_t for process CPU time. Linux version.
Copyright (C) 2004-2014 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <errno.h>
#include <time.h>
#include <unistd.h>
#include <kernel-features.h>
#include "kernel-posix-cpu-timers.h"
int
__clock_getcpuclockid (pid_t pid, clockid_t *clock_id)
{
/* The clockid_t value is a simple computation from the PID.
But we do a clock_getres call to validate it. */
const clockid_t pidclock = MAKE_PROCESS_CPUCLOCK (pid, CPUCLOCK_SCHED);
INTERNAL_SYSCALL_DECL (err);
int r = INTERNAL_SYSCALL (clock_getres, err, 2, pidclock, NULL);
if (!INTERNAL_SYSCALL_ERROR_P (r, err))
{
*clock_id = pidclock;
return 0;
}
if (INTERNAL_SYSCALL_ERRNO (r, err) == EINVAL)
{
/* The clock_getres system call checked the PID for us. */
return ESRCH;
}
else
return INTERNAL_SYSCALL_ERRNO (r, err);
}
weak_alias (__clock_getcpuclockid, clock_getcpuclockid)