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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>
59 lines
1.8 KiB
C
59 lines
1.8 KiB
C
/* gettimeofday - set time. 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 License as
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published by the Free Software Foundation; either version 2.1 of the
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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_GETTIMEOFDAY
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# include <time.h>
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# include <string.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 int
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__gettimeofday_syscall (struct timeval *restrict tv, void *restrict tz)
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{
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if (__glibc_unlikely (tz != 0))
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memset (tz, 0, sizeof *tz);
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return INLINE_SYSCALL_CALL (gettimeofday, tv, tz);
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}
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# undef INIT_ARCH
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# define INIT_ARCH() \
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void *vdso_gettimeofday = dl_vdso_vsym (HAVE_GETTIMEOFDAY_VSYSCALL)
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libc_ifunc (__gettimeofday,
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vdso_gettimeofday ? VDSO_IFUNC_RET (vdso_gettimeofday)
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: (void *) __gettimeofday_syscall)
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# else
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int
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__gettimeofday (struct timeval *restrict tv, void *restrict tz)
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{
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if (__glibc_unlikely (tz != 0))
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memset (tz, 0, sizeof *tz);
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return INLINE_VSYSCALL (gettimeofday, 2, tv, tz);
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}
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# endif
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weak_alias (__gettimeofday, gettimeofday)
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#else /* USE_IFUNC_GETTIMEOFDAY */
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# include <time/gettimeofday.c>
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#endif
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