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/* Bounded-pointer checking macros for C.
Copyright (C) 2000-2013 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Greg McGary <greg@mcgary.org>
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
<http://www.gnu.org/licenses/>. */
#ifndef _bp_checks_h_
#define _bp_checks_h_ 1
#if __BOUNDED_POINTERS__
# define BOUNDS_VIOLATED (__builtin_trap (), 0)
/* Verify that pointer's value >= low. Return pointer value. */
# define CHECK_BOUNDS_LOW(ARG) \
(((__ptrvalue (ARG) < __ptrlow (ARG)) && BOUNDS_VIOLATED), \
__ptrvalue (ARG))
/* Verify that pointer's value < high. Return pointer value. */
# define CHECK_BOUNDS_HIGH(ARG) \
(((__ptrvalue (ARG) > __ptrhigh (ARG)) && BOUNDS_VIOLATED), \
__ptrvalue (ARG))
# define _CHECK_N(ARG, N, COND) \
(((COND) \
&& (__ptrvalue (ARG) < __ptrlow (ARG) \
|| __ptrvalue (ARG) + (N) > __ptrhigh (ARG)) \
&& BOUNDS_VIOLATED), \
__ptrvalue (ARG))
extern void *__unbounded __ubp_memchr (const void *__unbounded, int, unsigned);
# define _CHECK_STRING(ARG, COND) \
(((COND) \
&& (__ptrvalue (ARG) < __ptrlow (ARG) \
|| !__ubp_memchr (__ptrvalue (ARG), '\0', \
(__ptrhigh (ARG) - __ptrvalue (ARG)))) \
&& BOUNDS_VIOLATED), \
__ptrvalue (ARG))
/* Check bounds of a pointer seated to an array of N objects. */
# define CHECK_N(ARG, N) _CHECK_N ((ARG), (N), 1)
/* Same as CHECK_N, but tolerate ARG == NULL. */
# define CHECK_N_NULL_OK(ARG, N) _CHECK_N ((ARG), (N), __ptrvalue (ARG))
/* Check bounds of a pointer seated to a single object. */
# define CHECK_1(ARG) CHECK_N ((ARG), 1)
/* Same as CHECK_1, but tolerate ARG == NULL. */
# define CHECK_1_NULL_OK(ARG) CHECK_N_NULL_OK ((ARG), 1)
/* Check for NUL-terminator within string's bounds. */
# define CHECK_STRING(ARG) _CHECK_STRING ((ARG), 1)
/* Same as CHECK_STRING, but tolerate ARG == NULL. */
# define CHECK_STRING_NULL_OK(ARG) _CHECK_STRING ((ARG), __ptrvalue (ARG))
# if defined (_IOC_SIZESHIFT) && defined (_IOC_SIZEBITS)
/* Extract the size of the ioctl data and check its bounds. */
# define CHECK_IOCTL(ARG, CMD) \
CHECK_N ((const char *) (ARG), \
(((CMD) >> _IOC_SIZESHIFT) & ((1 << _IOC_SIZEBITS) - 1)))
# else
/* We don't know the size of the ioctl data, so the best we can do
is check that the first byte is within bounds. */
# define CHECK_IOCTL(ARG, CMD) CHECK_1 ((const char *) ARG)
# endif
/* Check bounds of `struct flock *' for the locking fcntl commands. */
# define CHECK_FCNTL(ARG, CMD) \
(((CMD) == F_GETLK || (CMD) == F_SETLK || (CMD) == F_SETLKW) \
? CHECK_1 ((struct flock *) ARG) : (unsigned long) (ARG))
/* Check bounds of an array of mincore residency-status flags that
cover a region of NBYTES. Such a vector occupies one byte per page
of memory. */
# define CHECK_N_PAGES(ARG, NBYTES) \
({ int _page_size_ = sysconf (_SC_PAGE_SIZE); \
CHECK_N ((const char *) (ARG), \
((NBYTES) + _page_size_ - 1) / _page_size_); })
/* Return a bounded pointer with value PTR that satisfies CHECK_N (PTR, N). */
# define BOUNDED_N(PTR, N) \
({ __typeof (PTR) __bounded _p_; \
__ptrvalue _p_ = __ptrlow _p_ = __ptrvalue (PTR); \
__ptrhigh _p_ = __ptrvalue _p_ + (N); \
_p_; })
#else /* !__BOUNDED_POINTERS__ */
/* Do nothing if not compiling with -fbounded-pointers. */
# define BOUNDS_VIOLATED
# define CHECK_BOUNDS_LOW(ARG) (ARG)
# define CHECK_BOUNDS_HIGH(ARG) (ARG)
# define CHECK_1(ARG) (ARG)
# define CHECK_1_NULL_OK(ARG) (ARG)
# define CHECK_N(ARG, N) (ARG)
# define CHECK_N_NULL_OK(ARG, N) (ARG)
# define CHECK_STRING(ARG) (ARG)
# define CHECK_IOCTL(ARG, CMD) (ARG)
# define CHECK_FCNTL(ARG, CMD) (ARG)
# define CHECK_N_PAGES(ARG, NBYTES) (ARG)
# define BOUNDED_N(PTR, N) (PTR)
#endif /* !__BOUNDED_POINTERS__ */
#define BOUNDED_1(PTR) BOUNDED_N (PTR, 1)
#endif /* _bp_checks_h_ */
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