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89 lines
2.5 KiB
C
89 lines
2.5 KiB
C
/* clock_getcpuclockid -- Get a clockid_t for process CPU time. Linux version.
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Copyright (C) 2004-2012 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <errno.h>
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#include <time.h>
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#include <unistd.h>
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#include <kernel-features.h>
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#include "kernel-posix-cpu-timers.h"
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#ifndef HAS_CPUCLOCK
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# define HAS_CPUCLOCK 1
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#endif
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int
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clock_getcpuclockid (pid_t pid, clockid_t *clock_id)
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{
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#ifdef __NR_clock_getres
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/* The clockid_t value is a simple computation from the PID.
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But we do a clock_getres call to validate it. */
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const clockid_t pidclock = MAKE_PROCESS_CPUCLOCK (pid, CPUCLOCK_SCHED);
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# if !(__ASSUME_POSIX_CPU_TIMERS > 0)
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extern int __libc_missing_posix_cpu_timers attribute_hidden;
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if (!__libc_missing_posix_cpu_timers)
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# endif
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{
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INTERNAL_SYSCALL_DECL (err);
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int r = INTERNAL_SYSCALL (clock_getres, err, 2, pidclock, NULL);
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if (!INTERNAL_SYSCALL_ERROR_P (r, err))
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{
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*clock_id = pidclock;
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return 0;
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}
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if (INTERNAL_SYSCALL_ERRNO (r, err) == EINVAL)
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{
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# if !(__ASSUME_POSIX_CPU_TIMERS > 0)
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if (pidclock == MAKE_PROCESS_CPUCLOCK (0, CPUCLOCK_SCHED)
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|| INTERNAL_SYSCALL_ERROR_P (INTERNAL_SYSCALL
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(clock_getres, err, 2,
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MAKE_PROCESS_CPUCLOCK
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(0, CPUCLOCK_SCHED), NULL),
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err))
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/* The kernel doesn't support these clocks at all. */
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__libc_missing_posix_cpu_timers = 1;
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else
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# endif
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/* The clock_getres system call checked the PID for us. */
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return ESRCH;
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}
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else
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return INTERNAL_SYSCALL_ERRNO (r, err);
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}
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#endif
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/* We don't allow any process ID but our own. */
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if (pid != 0 && pid != getpid ())
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return EPERM;
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#ifdef CLOCK_PROCESS_CPUTIME_ID
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if (HAS_CPUCLOCK)
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{
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/* Store the number. */
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*clock_id = CLOCK_PROCESS_CPUTIME_ID;
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return 0;
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}
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#endif
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/* We don't have a timer for that. */
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return ENOENT;
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}
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