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* y2038: linux: Provide __clock_adjtime64 implementationLukasz Majewski2020-05-201-0/+73
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 <adhemerval.zanella@linaro.org>