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1bdda52fe9
This patch moves the vDSO setup from libc to loader code, just after the vDSO link_map setup. For static case the initialization is moved to _dl_non_dynamic_init instead. Instead of using the mangled pointer, the vDSO data is set as attribute_relro (on _rtld_global_ro for shared or _dl_vdso_* for static). It is read-only even with partial relro. It fixes BZ#24967 now that the vDSO pointer is setup earlier than malloc interposition is called. Also, vDSO calls should not be a problem for static dlopen as indicated by BZ#20802. The vDSO pointer would be zero-initialized and the syscall will be issued instead. Checked on x86_64-linux-gnu, i686-linux-gnu, aarch64-linux-gnu, arm-linux-gnueabihf, powerpc64le-linux-gnu, powerpc64-linux-gnu, powerpc-linux-gnu, s390x-linux-gnu, sparc64-linux-gnu, and sparcv9-linux-gnu. I also run some tests on mips. Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
52 lines
1.5 KiB
C
52 lines
1.5 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/time.c>
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#endif
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