xsize.h

Absolute File Name:

/home/opencoverage/opencoverage/guest-scripts/coreutils/src/lib/xsize.h

Line	Source	Count
1	/* xsize.h -- Checked size_t computations.	-
2		-
3	Copyright (C) 2003, 2008-2018 Free Software Foundation, Inc.	-
4		-
5	This program is free software; you can redistribute it and/or modify	-
6	it under the terms of the GNU General Public License as published by	-
7	the Free Software Foundation; either version 3, or (at your option)	-
8	any later version.	-
9		-
10	This program is distributed in the hope that it will be useful,	-
11	but WITHOUT ANY WARRANTY; without even the implied warranty of	-
12	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the	-
13	GNU General Public License for more details.	-
14		-
15	You should have received a copy of the GNU General Public License	-
16	along with this program; if not, see <https://www.gnu.org/licenses/>. */	-
17		-
18	#ifndef _XSIZE_H	-
19	#define _XSIZE_H	-
20		-
21	/* Get size_t. */	-
22	#include <stddef.h>	-
23		-
24	/* Get SIZE_MAX. */	-
25	#include <limits.h>	-
26	#if HAVE_STDINT_H	-
27	# include <stdint.h>	-
28	#endif	-
29		-
30	#ifndef _GL_INLINE_HEADER_BEGIN	-
31	#error "Please include config.h first."	-
32	#endif	-
33	_GL_INLINE_HEADER_BEGIN	-
34	#ifndef XSIZE_INLINE	-
35	# define XSIZE_INLINE _GL_INLINE	-
36	#endif	-
37		-
38	/* The size of memory objects is often computed through expressions of	-
39	type size_t. Example:	-
40	void* p = malloc (header_size + n * element_size).	-
41	These computations can lead to overflow. When this happens, malloc()	-
42	returns a piece of memory that is way too small, and the program then	-
43	crashes while attempting to fill the memory.	-
44	To avoid this, the functions and macros in this file check for overflow.	-
45	The convention is that SIZE_MAX represents overflow.	-
46	malloc (SIZE_MAX) is not guaranteed to fail -- think of a malloc	-
47	implementation that uses mmap --, it's recommended to use size_overflow_p()	-
48	or size_in_bounds_p() before invoking malloc().	-
49	The example thus becomes:	-
50	size_t size = xsum (header_size, xtimes (n, element_size));	-
51	void *p = (size_in_bounds_p (size) ? malloc (size) : NULL);	-
52	*/	-
53		-
54	/* Convert an arbitrary value >= 0 to type size_t. */	-
55	#define xcast_size_t(N) \	-
56	((N) <= SIZE_MAX ? (size_t) (N) : SIZE_MAX)	-
57		-
58	/* Sum of two sizes, with overflow check. */	-
59	XSIZE_INLINE size_t	-
60	#if __GNUC__ >= 3	-
61	__attribute__ ((__pure__))	-
62	#endif	-
63	xsum (size_t size1, size_t size2)	-
64	{	-
65	size_t sum = size1 + size2;	-
66	return (sum >= size1 ? sum : SIZE_MAX); executed 432 times by 1 test: `return (sum >= size1 ? sum : (18446744073709551615UL) );` Executed by: stat	432
67	}	-
68		-
69	/* Sum of three sizes, with overflow check. */	-
70	XSIZE_INLINE size_t	-
71	#if __GNUC__ >= 3	-
72	__attribute__ ((__pure__))	-
73	#endif	-
74	xsum3 (size_t size1, size_t size2, size_t size3)	-
75	{	-
76	return xsum (xsum (size1, size2), size3); never executed: `return xsum (xsum (size1, size2), size3);`	0
77	}	-
78		-
79	/* Sum of four sizes, with overflow check. */	-
80	XSIZE_INLINE size_t	-
81	#if __GNUC__ >= 3	-
82	__attribute__ ((__pure__))	-
83	#endif	-
84	xsum4 (size_t size1, size_t size2, size_t size3, size_t size4)	-
85	{	-
86	return xsum (xsum (xsum (size1, size2), size3), size4); never executed: `return xsum (xsum (xsum (size1, size2), size3), size4);`	0
87	}	-
88		-
89	/* Maximum of two sizes, with overflow check. */	-
90	XSIZE_INLINE size_t	-
91	#if __GNUC__ >= 3	-
92	__attribute__ ((__pure__))	-
93	#endif	-
94	xmax (size_t size1, size_t size2)	-
95	{	-
96	/* No explicit check is needed here, because for any n:	-
97	max (SIZE_MAX, n) == SIZE_MAX and max (n, SIZE_MAX) == SIZE_MAX. */	-
98	return (size1 >= size2 ? size1 : size2); never executed: `return (size1 >= size2 ? size1 : size2);`	0
99	}	-
100		-
101	/* Multiplication of a count with an element size, with overflow check.	-
102	The count must be >= 0 and the element size must be > 0.	-
103	This is a macro, not a function, so that it works correctly even	-
104	when N is of a wider type and N > SIZE_MAX. */	-
105	#define xtimes(N, ELSIZE) \	-
106	((N) <= SIZE_MAX / (ELSIZE) ? (size_t) (N) * (ELSIZE) : SIZE_MAX)	-
107		-
108	/* Check for overflow. */	-
109	#define size_overflow_p(SIZE) \	-
110	((SIZE) == SIZE_MAX)	-
111	/* Check against overflow. */	-
112	#define size_in_bounds_p(SIZE) \	-
113	((SIZE) != SIZE_MAX)	-
114		-
115	_GL_INLINE_HEADER_END	-
116		-
117	#endif /* _XSIZE_H */	-

Line

Source

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/* xsize.h -- Checked size_t computations.

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, see <https://www.gnu.org/licenses/>. */

#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

#ifndef _GL_INLINE_HEADER_BEGIN

#error "Please include config.h first."

#endif

_GL_INLINE_HEADER_BEGIN

#ifndef XSIZE_INLINE

# define XSIZE_INLINE _GL_INLINE

#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. */

XSIZE_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);

executed 432 times by 1 test: return (sum >= size1 ? sum : (18446744073709551615UL) );

Executed by:

stat

432

}

/* Sum of three sizes, with overflow check. */

XSIZE_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);

never executed: return xsum (xsum (size1, size2), size3);

}

/* Sum of four sizes, with overflow check. */

XSIZE_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);

never executed: return xsum (xsum (xsum (size1, size2), size3), size4);

}

/* Maximum of two sizes, with overflow check. */

XSIZE_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);

never executed: return (size1 >= size2 ? size1 : size2);

}

100

101

/* Multiplication of a count with an element size, with overflow check.

102

The count must be >= 0 and the element size must be > 0.

103

This is a macro, not a function, so that it works correctly even

104

when N is of a wider type and N > SIZE_MAX. */

105

#define xtimes(N, ELSIZE) \

106

((N) <= SIZE_MAX / (ELSIZE) ? (size_t) (N) * (ELSIZE) : SIZE_MAX)

107

108

/* Check for overflow. */

109

#define size_overflow_p(SIZE) \

110

((SIZE) == SIZE_MAX)

111

/* Check against overflow. */

112

#define size_in_bounds_p(SIZE) \

113

((SIZE) != SIZE_MAX)

114

115

_GL_INLINE_HEADER_END

116

117

#endif /* _XSIZE_H */

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