From 63ff4a6d1732e7472cbfa59a8f31db0441269105 Mon Sep 17 00:00:00 2001 From: Lukasz Majewski Date: Tue, 21 Apr 2020 19:14:18 +0200 Subject: y2038: linux: Provide __clock_adjtime64 implementation This patch replaces auto generated wrapper (as described in sysdeps/unix/sysv/linux/syscalls.list) for clock_adjtime with one which adds extra support for reading 64 bit time values on machines with __TIMESIZE != 64. To achieve this goal new __clock_adjtime64 explicit 64 bit function for adjusting Linux clock has been added. Moreover, a 32 bit version - __clock_adjtime has been refactored to internally use __clock_adjtime64. The __clock_adjtime is now supposed to be used on systems still supporting 32 bit time (__TIMESIZE != 64) - hence the necessary conversions between 64 bit struct __timespec64 and struct timespec. The new __clock_adjtime64 syscall available from Linux 5.1+ has been used, when applicable. Up till v5.4 in the Linux kernel there was a bug preventing this call from obtaining correct struct's timex time.tv_sec time after time_t overflow (i.e. not being Y2038 safe). 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 Linux kernel, headers and minimal kernel version for glibc build test matrix: - Linux v5.1 (with clock_adjtime64) and glibc build with v5.1 as minimal kernel version (--enable-kernel="5.1.0") The __ASSUME_TIME64_SYSCALLS flag defined. - Linux v5.1 and default minimal kernel version The __ASSUME_TIME64_SYSCALLS not defined, but kernel supports clock_adjtime64 syscall. - Linux v4.19 (no clock_adjtime64 support) with default minimal kernel version for contemporary glibc (3.2.0) This kernel doesn't support clock_adjtime64 syscall, so the fallback to clock_adjtime is tested. Above tests were performed with Y2038 redirection applied as well as without (so the __TIMESIZE != 64 execution path is checked as well). No regressions were observed. Reviewed-by: Adhemerval Zanella --- sysdeps/unix/sysv/linux/include/sys/timex.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'sysdeps/unix/sysv/linux/include') diff --git a/sysdeps/unix/sysv/linux/include/sys/timex.h b/sysdeps/unix/sysv/linux/include/sys/timex.h index 3efe7cd306..2848c5cf76 100644 --- a/sysdeps/unix/sysv/linux/include/sys/timex.h +++ b/sysdeps/unix/sysv/linux/include/sys/timex.h @@ -30,6 +30,7 @@ libc_hidden_proto (__adjtimex) /* Local definition of 64 bit time supporting timex struct */ # if __TIMESIZE == 64 # define __timex64 timex +# define __clock_adjtime64 __clock_adjtime # else struct __timex64 @@ -71,6 +72,8 @@ struct __timex64 int :32; int :32; }; +extern int __clock_adjtime64 (const clockid_t clock_id, struct __timex64 *tx64); +libc_hidden_proto (__clock_adjtime64); # endif /* Convert a known valid struct timex into a struct __timex64. */ -- cgit v1.2.3-70-g09d2