15c6926126
* Add gnulib files generated by gnulib-tool in build-aux, m4 and
grub-core/gnulib directories
* .bzignore: Add **/.deps and autogenerated gnulib files
* configure.ac: Assign auxiliary directory to build-aux, add invocation
of gnulib macros, add grub-core/gnulib/Makefile
* Makefile.am: Add gnulib directory in SUBDIRS (removing unnecessary .),
include m4 directory to aclocal.
* Makefile.util.def: Remove direct compilation of gnulib source files
and use the new grub-core/gnulib/libgnu.a.
* build-aux/config.rpath: move config.rpath from top directory to
build-aux
* conf/Makefile.common: Remove the macro _GL_UNUSED already defined
in gnulib headers
* conf/Makefile.extra-dist: Add m4/gnulib-cache.m4
* grub-core/Makefile.core.def: Remove unnecessary extra_dist
* grub-core/lib/posix_wrap/localcharset.h (locale_charset): Update
header.
* grub-core/lib/posix_wrap/langinfo.h (nl_langinfo): Return static
string.
108 lines
3.5 KiB
C
108 lines
3.5 KiB
C
/* xsize.h -- Checked size_t computations.
|
|
|
|
Copyright (C) 2003, 2008, 2009, 2010 Free Software Foundation, Inc.
|
|
|
|
This program is free software; you can redistribute it and/or modify
|
|
it under the terms of the GNU General Public License as published by
|
|
the Free Software Foundation; either version 3, or (at your option)
|
|
any later version.
|
|
|
|
This program 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 General Public License for more details.
|
|
|
|
You should have received a copy of the GNU General Public License
|
|
along with this program; if not, write to the Free Software Foundation,
|
|
Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
|
|
|
|
#ifndef _XSIZE_H
|
|
#define _XSIZE_H
|
|
|
|
/* Get size_t. */
|
|
#include <stddef.h>
|
|
|
|
/* Get SIZE_MAX. */
|
|
#include <limits.h>
|
|
#if HAVE_STDINT_H
|
|
# include <stdint.h>
|
|
#endif
|
|
|
|
/* The size of memory objects is often computed through expressions of
|
|
type size_t. Example:
|
|
void* p = malloc (header_size + n * element_size).
|
|
These computations can lead to overflow. When this happens, malloc()
|
|
returns a piece of memory that is way too small, and the program then
|
|
crashes while attempting to fill the memory.
|
|
To avoid this, the functions and macros in this file check for overflow.
|
|
The convention is that SIZE_MAX represents overflow.
|
|
malloc (SIZE_MAX) is not guaranteed to fail -- think of a malloc
|
|
implementation that uses mmap --, it's recommended to use size_overflow_p()
|
|
or size_in_bounds_p() before invoking malloc().
|
|
The example thus becomes:
|
|
size_t size = xsum (header_size, xtimes (n, element_size));
|
|
void *p = (size_in_bounds_p (size) ? malloc (size) : NULL);
|
|
*/
|
|
|
|
/* Convert an arbitrary value >= 0 to type size_t. */
|
|
#define xcast_size_t(N) \
|
|
((N) <= SIZE_MAX ? (size_t) (N) : SIZE_MAX)
|
|
|
|
/* Sum of two sizes, with overflow check. */
|
|
static inline size_t
|
|
#if __GNUC__ >= 3
|
|
__attribute__ ((__pure__))
|
|
#endif
|
|
xsum (size_t size1, size_t size2)
|
|
{
|
|
size_t sum = size1 + size2;
|
|
return (sum >= size1 ? sum : SIZE_MAX);
|
|
}
|
|
|
|
/* Sum of three sizes, with overflow check. */
|
|
static inline size_t
|
|
#if __GNUC__ >= 3
|
|
__attribute__ ((__pure__))
|
|
#endif
|
|
xsum3 (size_t size1, size_t size2, size_t size3)
|
|
{
|
|
return xsum (xsum (size1, size2), size3);
|
|
}
|
|
|
|
/* Sum of four sizes, with overflow check. */
|
|
static inline size_t
|
|
#if __GNUC__ >= 3
|
|
__attribute__ ((__pure__))
|
|
#endif
|
|
xsum4 (size_t size1, size_t size2, size_t size3, size_t size4)
|
|
{
|
|
return xsum (xsum (xsum (size1, size2), size3), size4);
|
|
}
|
|
|
|
/* Maximum of two sizes, with overflow check. */
|
|
static inline size_t
|
|
#if __GNUC__ >= 3
|
|
__attribute__ ((__pure__))
|
|
#endif
|
|
xmax (size_t size1, size_t size2)
|
|
{
|
|
/* No explicit check is needed here, because for any n:
|
|
max (SIZE_MAX, n) == SIZE_MAX and max (n, SIZE_MAX) == SIZE_MAX. */
|
|
return (size1 >= size2 ? size1 : size2);
|
|
}
|
|
|
|
/* Multiplication of a count with an element size, with overflow check.
|
|
The count must be >= 0 and the element size must be > 0.
|
|
This is a macro, not an inline function, so that it works correctly even
|
|
when N is of a wider type and N > SIZE_MAX. */
|
|
#define xtimes(N, ELSIZE) \
|
|
((N) <= SIZE_MAX / (ELSIZE) ? (size_t) (N) * (ELSIZE) : SIZE_MAX)
|
|
|
|
/* Check for overflow. */
|
|
#define size_overflow_p(SIZE) \
|
|
((SIZE) == SIZE_MAX)
|
|
/* Check against overflow. */
|
|
#define size_in_bounds_p(SIZE) \
|
|
((SIZE) != SIZE_MAX)
|
|
|
|
#endif /* _XSIZE_H */
|