1/* clock_getcpuclockid -- Get a clockid_t for process CPU time. Linux version.
2 Copyright (C) 2004-2020 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 <shlib-compat.h>
24
25int
26__clock_getcpuclockid (pid_t pid, clockid_t *clock_id)
27{
28 /* The clockid_t value is a simple computation from the PID.
29 But we do a clock_getres call to validate it. */
30
31 const clockid_t pidclock = MAKE_PROCESS_CPUCLOCK (pid, CPUCLOCK_SCHED);
32
33 INTERNAL_SYSCALL_DECL (err);
34 int r = INTERNAL_SYSCALL (clock_getres, err, 2, pidclock, NULL);
35 if (!INTERNAL_SYSCALL_ERROR_P (r, err))
36 {
37 *clock_id = pidclock;
38 return 0;
39 }
40
41 if (INTERNAL_SYSCALL_ERRNO (r, err) == EINVAL)
42 {
43 /* The clock_getres system call checked the PID for us. */
44 return ESRCH;
45 }
46 else
47 return INTERNAL_SYSCALL_ERRNO (r, err);
48}
49
50versioned_symbol (libc, __clock_getcpuclockid, clock_getcpuclockid, GLIBC_2_17);
51/* clock_getcpuclockid moved to libc in version 2.17;
52 old binaries may expect the symbol version it had in librt. */
53#if SHLIB_COMPAT (libc, GLIBC_2_2, GLIBC_2_17)
54strong_alias (__clock_getcpuclockid, __clock_getcpuclockid_2);
55compat_symbol (libc, __clock_getcpuclockid_2, clock_getcpuclockid, GLIBC_2_2);
56#endif
57