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75c4044b9a
In the glibc the time function can use vDSO (on power and x86 the USE_IFUNC_TIME is defined), time syscall or 'default' time() from ./time/time.c (as a fallback). In this patch the last function (time) has been refactored and moved to ./sysdeps/unix/sysv/linux/time.c to be Linux specific. The new __time64 explicit 64 bit function for providing 64 bit value of seconds after epoch (by internally calling __clock_gettime64) has been introduced. Moreover, a 32 bit version - __time has been refactored to internally use __time64. The __time is now supposed to be used on systems still supporting 32 bit time (__TIMESIZE != 64) - hence the necessary check for time_t potential overflow. The iFUNC vDSO direct call optimization has been removed from both i686 and powerpc32 (USE_IFUNC_TIME is not defined for those architectures anymore). The Linux kernel does not provide a y2038 safe implementation of time neither it plans to provide it in the future, __clock_gettime64 should be used instead. Keeping support for this optimization would require to handle another build permutation (!__ASSUME_TIME64_SYSCALLS && USE_IFUNC_TIME which adds more complexity and has limited use (since the idea is to eventually have a y2038 safe glibc build). Build tests: ./src/scripts/build-many-glibcs.py glibcs Run-time tests: - Run specific tests on ARM/x86 32bit systems (qemu): https://github.com/lmajewski/meta-y2038 and run tests: https://github.com/lmajewski/y2038-tests/commits/master Above tests were performed with Y2038 redirection applied as well as without to test proper usage of both __time64 and __time. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
88 lines
2.0 KiB
C
88 lines
2.0 KiB
C
/* time -- Get number of seconds since Epoch. Linux version.
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Copyright (C) 2020 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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<https://www.gnu.org/licenses/>. */
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/* Optimize the function call by setting the PLT directly to vDSO symbol. */
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#ifdef USE_IFUNC_TIME
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# include <time.h>
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# include <sysdep.h>
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# include <sysdep-vdso.h>
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#ifdef SHARED
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# include <dl-vdso.h>
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# include <libc-vdso.h>
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static time_t
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time_syscall (time_t *t)
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{
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return INLINE_SYSCALL_CALL (time, t);
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}
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# undef INIT_ARCH
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# define INIT_ARCH() \
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void *vdso_time = dl_vdso_vsym (HAVE_TIME_VSYSCALL);
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libc_ifunc (time,
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vdso_time ? VDSO_IFUNC_RET (vdso_time)
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: (void *) time_syscall);
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# else
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time_t
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time (time_t *t)
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{
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return INLINE_VSYSCALL (time, 1, t);
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}
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# endif /* !SHARED */
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#else /* USE_IFUNC_TIME */
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# include <time.h>
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# include <time-clockid.h>
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# include <errno.h>
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/* Return the time now, and store it in *TIMER if not NULL. */
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__time64_t
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__time64 (__time64_t *timer)
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{
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struct __timespec64 ts;
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__clock_gettime64 (TIME_CLOCK_GETTIME_CLOCKID, &ts);
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if (timer != NULL)
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*timer = ts.tv_sec;
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return ts.tv_sec;
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}
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# if __TIMESIZE != 64
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libc_hidden_def (__time64)
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time_t
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__time (time_t *timer)
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{
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__time64_t t = __time64 (NULL);
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if (! in_time_t_range (t))
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{
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__set_errno (EOVERFLOW);
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return -1;
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}
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if (timer != NULL)
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*timer = t;
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return t;
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}
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# endif
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weak_alias (__time, time)
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#endif
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