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ae8c243d24
The code to allocate a stack from xsigstack is refactored so it can be more generic. The new support_stack_alloc() also set PROT_EXEC if DEFAULT_STACK_PERMS has PF_X. This is required on some architectures (hppa for instance) and trying to access the rtld global from testsuite will require more intrusive refactoring in the ldsodefs.h header. Checked on x86_64-linux-gnu and i686-linux-gnu. I also ran tst-xsigstack on both hppa and ia64.
82 lines
2.5 KiB
C
82 lines
2.5 KiB
C
/* sigaltstack wrappers.
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Copyright (C) 2019-2021 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 <support/xsignal.h>
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#include <support/support.h>
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#include <support/xunistd.h>
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#include <support/check.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/mman.h>
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#include <sys/param.h> /* roundup, MAX */
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#ifndef MAP_NORESERVE
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# define MAP_NORESERVE 0
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#endif
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#ifndef MAP_STACK
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# define MAP_STACK 0
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#endif
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/* The "cookie" returned by xalloc_sigstack points to one of these
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structures. */
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struct sigstack_desc
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{
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struct support_stack stack;
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stack_t alt_stack; /* The address and size of the stack itself. */
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stack_t old_stack; /* The previous signal stack. */
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};
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void *
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xalloc_sigstack (size_t size)
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{
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struct sigstack_desc *desc = xmalloc (sizeof (struct sigstack_desc));
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desc->stack = support_stack_alloc (size);
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desc->alt_stack.ss_sp = desc->stack.stack;
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desc->alt_stack.ss_flags = 0;
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desc->alt_stack.ss_size = desc->stack.size;
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if (sigaltstack (&desc->alt_stack, &desc->old_stack))
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FAIL_EXIT1 ("sigaltstack (new stack: sp=%p, size=%zu, flags=%u): %m\n",
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desc->alt_stack.ss_sp, desc->alt_stack.ss_size,
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desc->alt_stack.ss_flags);
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return desc;
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}
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void
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xfree_sigstack (void *stack)
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{
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struct sigstack_desc *desc = stack;
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if (sigaltstack (&desc->old_stack, 0))
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FAIL_EXIT1 ("sigaltstack (restore old stack: sp=%p, size=%zu, flags=%u): "
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"%m\n", desc->old_stack.ss_sp, desc->old_stack.ss_size,
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desc->old_stack.ss_flags);
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support_stack_free (&desc->stack);
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free (desc);
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}
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void
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xget_sigstack_location (const void *stack, unsigned char **addrp, size_t *sizep)
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{
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const struct sigstack_desc *desc = stack;
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*addrp = desc->alt_stack.ss_sp;
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*sizep = desc->alt_stack.ss_size;
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}
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