1/* clock_getcpuclockid -- Get a clockid_t for process CPU time. Linux version.
2 Copyright (C) 2004-2021 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#include <errno.h>
20#include <time.h>
21#include <unistd.h>
22#include "kernel-posix-cpu-timers.h"
23#include <sysdep.h>
24#include <shlib-compat.h>
25
26int
27__clock_getcpuclockid (pid_t pid, clockid_t *clock_id)
28{
29 /* The clockid_t value is a simple computation from the PID.
30 But we do a clock_getres call to validate it. */
31
32 const clockid_t pidclock = MAKE_PROCESS_CPUCLOCK (pid, CPUCLOCK_SCHED);
33
34#ifndef __NR_clock_getres_time64
35# define __NR_clock_getres_time64 __NR_clock_getres
36#endif
37 int r = INTERNAL_SYSCALL_CALL (clock_getres_time64, pidclock, NULL);
38
39#ifndef __ASSUME_TIME64_SYSCALLS
40 if (r != 0 && r == -ENOSYS)
41 r = INTERNAL_SYSCALL_CALL (clock_getres, pidclock, NULL);
42#endif
43
44 if (r == 0)
45 {
46 *clock_id = pidclock;
47 return 0;
48 }
49 if (r == -EINVAL)
50 /* The clock_getres system call checked the PID for us. */
51 return ESRCH;
52 return -r;
53}
54
55versioned_symbol (libc, __clock_getcpuclockid, clock_getcpuclockid, GLIBC_2_17);
56/* clock_getcpuclockid moved to libc in version 2.17;
57 old binaries may expect the symbol version it had in librt. */
58#if SHLIB_COMPAT (libc, GLIBC_2_2, GLIBC_2_17)
59strong_alias (__clock_getcpuclockid, __clock_getcpuclockid_2);
60compat_symbol (libc, __clock_getcpuclockid_2, clock_getcpuclockid, GLIBC_2_2);
61#endif
62