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author | Lukasz Majewski <lukma@denx.de> | 2020-01-27 15:37:07 +0100 |
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committer | Lukasz Majewski <lukma@denx.de> | 2020-02-18 23:55:47 +0100 |
commit | 7455b700279ec8baccf8dd7b119648f8b3e34eec (patch) | |
tree | 3a973eeef955d4de9f3e312dedc7c7ce20d8cb8e /include | |
parent | Linux: Work around kernel bugs in chmod on /proc/self/fd paths [BZ #14578] (diff) | |
download | glibc-7455b700279ec8baccf8dd7b119648f8b3e34eec.tar.gz glibc-7455b700279ec8baccf8dd7b119648f8b3e34eec.tar.bz2 glibc-7455b700279ec8baccf8dd7b119648f8b3e34eec.zip |
y2038: linux: Provide __gettimeofday64 implementation
In the glibc the gettimeofday can use vDSO (on power and x86 the
USE_IFUNC_GETTIMEOFDAY is defined), gettimeofday syscall or 'default'
___gettimeofday() from ./time/gettime.c (as a fallback).
In this patch the last function (___gettimeofday) has been refactored and
moved to ./sysdeps/unix/sysv/linux/gettimeofday.c to be Linux specific.
The new __gettimeofday64 explicit 64 bit function for getting 64 bit time from
the kernel (by internally calling __clock_gettime64) has been introduced.
Moreover, a 32 bit version - __gettimeofday has been refactored to internally
use __gettimeofday64.
The __gettimeofday is now supposed to be used on systems still supporting 32
bit time (__TIMESIZE != 64) - hence the necessary check for time_t potential
overflow and conversion of struct __timeval64 to 32 bit struct timespec.
The iFUNC vDSO direct call optimization has been removed from both i686 and
powerpc32 (USE_IFUNC_GETTIMEOFDAY is not defined for those architectures
anymore). The Linux kernel does not provide a y2038 safe implementation of
gettimeofday 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_GETTIMEOFDAY) 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 __gettimeofday64 and __gettimeofday.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
[Including some commit message improvement]
Diffstat (limited to 'include')
-rw-r--r-- | include/time.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/include/time.h b/include/time.h index 73f66277ac..61806658e7 100644 --- a/include/time.h +++ b/include/time.h @@ -227,10 +227,14 @@ libc_hidden_proto (__sched_rr_get_interval64); #if __TIMESIZE == 64 # define __settimeofday64 __settimeofday +# define __gettimeofday64 __gettimeofday #else extern int __settimeofday64 (const struct __timeval64 *tv, const struct timezone *tz); libc_hidden_proto (__settimeofday64) +extern int __gettimeofday64 (struct __timeval64 *restrict tv, + void *restrict tz); +libc_hidden_proto (__gettimeofday64) #endif /* Compute the `struct tm' representation of T, |