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72e84d1db2
The previous approach defeats the vDSO optimization on older kernels because a failing clock_gettime64 system call is performed on every function call. It also results in a clobbered errno value, exposing an OpenJDK bug (JDK-8270244). This patch fixes by open-code INLINE_VSYSCALL macro and replace all INLINE_SYSCALL_CALL with INTERNAL_SYSCALL_CALLS. Now for __clock_gettime64x, the 64-bit vDSO is used and the 32-bit vDSO is tried before falling back to 64-bit syscalls. The previous code preferred 64-bit syscall for the case where the kernel provides 64-bit time_t syscalls *and* also a 32-bit vDSO (in this case the *64-bit* syscall should be preferable over the vDSO). All architectures that provides 32-bit vDSO (i386, mips, powerpc, s390) modulo sparc; but I am not sure if some kernels versions do provide only 32-bit vDSO while still providing 64-bit time_t syscall. Regardless, for such cases the 64-bit time_t syscall is used if the vDSO returns overflowed 32-bit time_t. Tested on i686-linux-gnu (with a time64 and non-time64 kernel), x86_64-linux-gnu. Built with build-many-glibcs.py. Co-authored-by: Florian Weimer <fweimer@redhat.com>
38 lines
1.2 KiB
C
38 lines
1.2 KiB
C
/* Check that gettimeofday does not clobber errno.
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Copyright (C) 2021 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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#include <errno.h>
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#include <stddef.h>
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#include <support/check.h>
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#include <sys/time.h>
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static int
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do_test (void)
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{
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for (int original_errno = 0; original_errno < 2; ++original_errno)
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{
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errno = original_errno;
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struct timeval tv;
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gettimeofday (&tv, NULL);
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TEST_COMPARE (errno, original_errno);
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}
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return 0;
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}
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#include <support/test-driver.c>
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