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/* Details about the machine's stack: wrapper header.
Copyright (C) 2014-2026 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#ifndef _INCLUDE_STACKINFO_H
#define _INCLUDE_STACKINFO_H 1
/* A sysdeps/.../stackinfo.h file defines details for the CPU.
It is obliged to define either _STACK_GROWS_DOWN or _STACK_GROWS_UP. */
#include_next <stackinfo.h>
#if defined _STACK_GROWS_DOWN && _STACK_GROWS_DOWN
# ifdef _STACK_GROWS_UP
# error "stackinfo.h should not define both!"
# else
# define _STACK_GROWS_UP 0
# endif
#elif defined _STACK_GROWS_UP && _STACK_GROWS_UP
# ifdef _STACK_GROWS_DOWN
# error "stackinfo.h should not define both!"
# else
# define _STACK_GROWS_DOWN 0
# endif
#else
# error "stackinfo.h must define _STACK_GROWS_UP or _STACK_GROWS_DOWN!"
#endif
#include <sys/mman.h>
#include <link.h>
/* ELF uses the PF_x macros to specify the segment permissions, mmap
uses PROT_xxx. In most cases the three macros have the values 1, 2,
and 4 but not in a matching order. The following macros allows
converting from the PF_x values to PROT_xxx values. */
#define PF_TO_PROT \
((PROT_READ << (PF_R * 4)) \
| (PROT_WRITE << (PF_W * 4)) \
| (PROT_EXEC << (PF_X * 4)) \
| ((PROT_READ | PROT_WRITE) << ((PF_R | PF_W) * 4)) \
| ((PROT_READ | PROT_EXEC) << ((PF_R | PF_X) * 4)) \
| ((PROT_WRITE | PROT_EXEC) << (PF_W | PF_X) * 4) \
| ((PROT_READ | PROT_WRITE | PROT_EXEC) << ((PF_R | PF_W | PF_X) * 4)))
static inline int
pf_to_prot (ElfW(Word) value)
{
#if (PF_R | PF_W | PF_X) == 7 && (PROT_READ | PROT_WRITE | PROT_EXEC) == 7
return (PF_TO_PROT >> ((value & (PF_R | PF_W | PF_X)) * 4)) & 0xf;
#else
ElfW(Word) ret = 0;
if (value & PF_R)
ret |= PROT_READ;
if (value & PF_W)
ret |= PROT_WRITE;
if (value & PF_X)
ret |= PROT_EXEC;
return ret;
#endif
}
#endif /* include/stackinfo.h */
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