--- Begin Message ---
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Subject: |
lisp_string_width and strings wider than INT_MAX |
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Date: |
Sun, 15 May 2011 22:07:36 -0700 |
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User-agent: |
Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.17) Gecko/20110424 Thunderbird/3.1.10 |
lisp_string_width requires that the precision be less than INT_MAX,
and if no precision is given, misbehaves badly when dealing with
strings whose widths are greater than INT_MAX. To address this, I
plan to install the following patch (PATCH 3) after some more testing.
PATCH 3 depends on two obvious patches: PATCH 2 introduces a helper
no-return function string_overflow, and PATCH 1 updates to the latest
version of gnulib.
One thing about PATCH 3: when used in Emacs, the new lisp_string_width
correctly signals an overflow when the string's width cannot be
represented, but when used outside Emacs (in mulelib) it silently
ignores the problem, just as before. I don't know much about mulelib
and so don't know how to address this. But anyway, mulelib uses
should be no worse off than before.
PATCH 3 ---------------------------------------------------
=== modified file 'src/ChangeLog'
--- src/ChangeLog 2011-05-16 01:11:54 +0000
+++ src/ChangeLog 2011-05-16 01:25:38 +0000
@@ -1,5 +1,14 @@
2011-05-16 Paul Eggert <address@hidden>
+ * character.c (lisp_string_width): Check for string overflow.
+ Use EMACS_INT, not int, for string indexes and lengths; in
+ particular, 2nd arg is now EMACS_INT, not int. Do not crash if
+ the resulting string length overflows an EMACS_INT; instead,
+ report a string overflow if no precision given. When checking for
+ precision exhaustion, use a check that cannot possibly have
+ integer overflow.
+ * character.h (lisp_string_width): Adjust to new signature.
+
* alloc.c (string_overflow): New function.
(Fmake_string): Use it. This doesn't change behavior, but saves
a few bytes and will simplify future changes.
=== modified file 'src/character.c'
--- src/character.c 2011-05-16 01:11:54 +0000
+++ src/character.c 2011-05-16 01:17:19 +0000
@@ -35,6 +35,7 @@
#include <sys/types.h>
#include <setjmp.h>
+#include <intprops.h>
#include "lisp.h"
#include "character.h"
#include "buffer.h"
@@ -404,7 +405,7 @@
in *NCHARS and *NBYTES respectively. */
EMACS_INT
-lisp_string_width (Lisp_Object string, int precision,
+lisp_string_width (Lisp_Object string, EMACS_INT precision,
EMACS_INT *nchars, EMACS_INT *nbytes)
{
EMACS_INT len = SCHARS (string);
@@ -419,7 +420,7 @@
while (i < len)
{
- int chars, bytes, thiswidth;
+ EMACS_INT chars, bytes, thiswidth;
Lisp_Object val;
int cmp_id;
EMACS_INT ignore, end;
@@ -437,7 +438,11 @@
int c;
if (multibyte)
- c = STRING_CHAR_AND_LENGTH (str + i_byte, bytes);
+ {
+ int cbytes;
+ c = STRING_CHAR_AND_LENGTH (str + i_byte, cbytes);
+ bytes = cbytes;
+ }
else
c = str[i_byte], bytes = 1;
chars = 1;
@@ -455,8 +460,14 @@
}
}
- if (precision > 0
- && (width + thiswidth > precision))
+ if (precision <= 0)
+ {
+#ifdef emacs
+ if (INT_ADD_OVERFLOW (width, thiswidth))
+ string_overflow ();
+#endif
+ }
+ else if (precision - width < thiswidth)
{
*nchars = i;
*nbytes = i_byte;
=== modified file 'src/character.h'
--- src/character.h 2011-04-11 03:39:45 +0000
+++ src/character.h 2011-05-16 01:13:28 +0000
@@ -612,7 +612,7 @@
extern EMACS_INT strwidth (const char *, EMACS_INT);
extern EMACS_INT c_string_width (const unsigned char *, EMACS_INT, int,
EMACS_INT *, EMACS_INT *);
-extern EMACS_INT lisp_string_width (Lisp_Object, int,
+extern EMACS_INT lisp_string_width (Lisp_Object, EMACS_INT,
EMACS_INT *, EMACS_INT *);
extern Lisp_Object Qcharacterp;
PATCH 2 ---------------------------------------------------
=== modified file 'src/ChangeLog'
--- src/ChangeLog 2011-05-15 17:17:44 +0000
+++ src/ChangeLog 2011-05-16 01:11:54 +0000
@@ -1,3 +1,11 @@
+2011-05-16 Paul Eggert <address@hidden>
+
+ * alloc.c (string_overflow): New function.
+ (Fmake_string): Use it. This doesn't change behavior, but saves
+ a few bytes and will simplify future changes.
+ * character.c (string_escape_byte8): Likewise.
+ * lisp.h (string_overflow): New decl.
+
2011-05-15 Paul Eggert <address@hidden>
Fixups, following up to the user-interface timestamp change.
=== modified file 'src/alloc.c'
--- src/alloc.c 2011-05-12 07:07:06 +0000
+++ src/alloc.c 2011-05-16 01:11:54 +0000
@@ -2174,6 +2174,11 @@
current_sblock = tb;
}
+void
+string_overflow (void)
+{
+ error ("Maximum string size exceeded");
+}
DEFUN ("make-string", Fmake_string, Smake_string, 2, 2, 0,
doc: /* Return a newly created string of length LENGTH, with INIT in
each element.
@@ -2206,7 +2211,7 @@
EMACS_INT string_len = XINT (length);
if (string_len > MOST_POSITIVE_FIXNUM / len)
- error ("Maximum string size exceeded");
+ string_overflow ();
nbytes = len * string_len;
val = make_uninit_multibyte_string (string_len, nbytes);
p = SDATA (val);
=== modified file 'src/character.c'
--- src/character.c 2011-05-12 07:07:06 +0000
+++ src/character.c 2011-05-16 01:11:54 +0000
@@ -823,7 +823,7 @@
{
if ((MOST_POSITIVE_FIXNUM - nchars) / 3 < byte8_count
|| (MOST_POSITIVE_FIXNUM - nbytes) / 2 < byte8_count)
- error ("Maximum string size exceeded");
+ string_overflow ();
/* Convert 2-byte sequence of byte8 chars to 4-byte octal. */
val = make_uninit_multibyte_string (nchars + byte8_count * 3,
@@ -832,7 +832,7 @@
else
{
if ((MOST_POSITIVE_FIXNUM - nchars) / 3 < byte8_count)
- error ("Maximum string size exceeded");
+ string_overflow ();
/* Convert 1-byte sequence of byte8 chars to 4-byte octal. */
val = make_uninit_string (nbytes + byte8_count * 3);
}
=== modified file 'src/lisp.h'
--- src/lisp.h 2011-05-15 17:17:44 +0000
+++ src/lisp.h 2011-05-16 01:11:54 +0000
@@ -2710,6 +2710,7 @@
EXFUN (Fvector, MANY);
EXFUN (Fmake_symbol, 1);
EXFUN (Fmake_marker, 0);
+extern void string_overflow (void) NO_RETURN;
EXFUN (Fmake_string, 2);
extern Lisp_Object build_string (const char *);
extern Lisp_Object make_string (const char *, EMACS_INT);
PATCH 1 ---------------------------------------------------
=== modified file 'doc/misc/texinfo.tex'
--- doc/misc/texinfo.tex 2011-04-06 05:07:27 +0000
+++ doc/misc/texinfo.tex 2011-05-16 00:51:54 +0000
@@ -3,7 +3,7 @@
% Load plain if necessary, i.e., if running under initex.
\expandafter\ifx\csname fmtname\endcsname\relax\input plain\fi
%
-\def\texinfoversion{2011-03-25.11}
+\def\texinfoversion{2011-05-11.16}
%
% Copyright 1985, 1986, 1988, 1990, 1991, 1992, 1993, 1994, 1995,
% 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006,
@@ -8424,7 +8424,7 @@
%
% Latin1 (ISO-8859-1) character definitions.
\def\latonechardefs{%
- \gdef^^a0{~}
+ \gdef^^a0{\tie}
\gdef^^a1{\exclamdown}
\gdef^^a2{\missingcharmsg{CENT SIGN}}
\gdef^^a3{{\pounds}}
@@ -8546,7 +8546,7 @@
% Latin2 (ISO-8859-2) character definitions.
\def\lattwochardefs{%
- \gdef^^a0{~}
+ \gdef^^a0{\tie}
\gdef^^a1{\ogonek{A}}
\gdef^^a2{\u{}}
\gdef^^a3{\L}
@@ -9395,6 +9395,8 @@
\message{and turning on texinfo input format.}
+\def^^L{\par} % remove \outer, so ^L can appear in an @comment
+
% DEL is a comment character, in case @c does not suffice.
\catcode`\^^? = 14
=== modified file 'lib/gnulib.mk'
--- lib/gnulib.mk 2011-05-04 07:19:21 +0000
+++ lib/gnulib.mk 2011-05-16 00:51:54 +0000
@@ -167,7 +167,8 @@
## begin gnulib module ignore-value
-libgnu_a_SOURCES += ignore-value.h
+
+EXTRA_DIST += ignore-value.h
## end gnulib module ignore-value
@@ -779,6 +780,7 @@
-e 's|@''GNULIB_GETLOGIN_R''@|$(GNULIB_GETLOGIN_R)|g' \
-e 's|@''GNULIB_GETPAGESIZE''@|$(GNULIB_GETPAGESIZE)|g' \
-e 's|@''GNULIB_GETUSERSHELL''@|$(GNULIB_GETUSERSHELL)|g' \
+ -e 's|@''GNULIB_GROUP_MEMBER''@|$(GNULIB_GROUP_MEMBER)|g' \
-e 's|@''GNULIB_LCHOWN''@|$(GNULIB_LCHOWN)|g' \
-e 's|@''GNULIB_LINK''@|$(GNULIB_LINK)|g' \
-e 's|@''GNULIB_LINKAT''@|$(GNULIB_LINKAT)|g' \
@@ -817,6 +819,7 @@
-e 's|@''HAVE_GETHOSTNAME''@|$(HAVE_GETHOSTNAME)|g' \
-e 's|@''HAVE_GETLOGIN''@|$(HAVE_GETLOGIN)|g' \
-e 's|@''HAVE_GETPAGESIZE''@|$(HAVE_GETPAGESIZE)|g' \
+ -e 's|@''HAVE_GROUP_MEMBER''@|$(HAVE_GROUP_MEMBER)|g' \
-e 's|@''HAVE_LCHOWN''@|$(HAVE_LCHOWN)|g' \
-e 's|@''HAVE_LINK''@|$(HAVE_LINK)|g' \
-e 's|@''HAVE_LINKAT''@|$(HAVE_LINKAT)|g' \
@@ -883,9 +886,10 @@
## begin gnulib module verify
if gl_GNULIB_ENABLED_verify
-libgnu_a_SOURCES += verify.h
endif
+EXTRA_DIST += verify.h
+
## end gnulib module verify
## begin gnulib module warn-on-use
=== modified file 'lib/intprops.h'
--- lib/intprops.h 2011-01-30 19:22:02 +0000
+++ lib/intprops.h 2011-05-16 00:51:54 +0000
@@ -17,70 +17,298 @@
/* Written by Paul Eggert. */
-#ifndef GL_INTPROPS_H
-# define GL_INTPROPS_H
-
-# include <limits.h>
+#ifndef _GL_INTPROPS_H
+#define _GL_INTPROPS_H
+
+#include <limits.h>
+
+/* Return a integer value, converted to the same type as the integer
+ expression E after integer type promotion. V is the unconverted value.
+ E should not have side effects. */
+#define _GL_INT_CONVERT(e, v) ((e) - (e) + (v))
/* The extra casts in the following macros work around compiler bugs,
e.g., in Cray C 5.0.3.0. */
/* True if the arithmetic type T is an integer type. bool counts as
an integer. */
-# define TYPE_IS_INTEGER(t) ((t) 1.5 == 1)
+#define TYPE_IS_INTEGER(t) ((t) 1.5 == 1)
/* True if negative values of the signed integer type T use two's
complement, ones' complement, or signed magnitude representation,
respectively. Much GNU code assumes two's complement, but some
people like to be portable to all possible C hosts. */
-# define TYPE_TWOS_COMPLEMENT(t) ((t) ~ (t) 0 == (t) -1)
-# define TYPE_ONES_COMPLEMENT(t) ((t) ~ (t) 0 == 0)
-# define TYPE_SIGNED_MAGNITUDE(t) ((t) ~ (t) 0 < (t) -1)
+#define TYPE_TWOS_COMPLEMENT(t) ((t) ~ (t) 0 == (t) -1)
+#define TYPE_ONES_COMPLEMENT(t) ((t) ~ (t) 0 == 0)
+#define TYPE_SIGNED_MAGNITUDE(t) ((t) ~ (t) 0 < (t) -1)
+
+/* True if the signed integer expression E uses two's complement. */
+#define _GL_INT_TWOS_COMPLEMENT(e) (~ _GL_INT_CONVERT (e, 0) == -1)
/* True if the arithmetic type T is signed. */
-# define TYPE_SIGNED(t) (! ((t) 0 < (t) -1))
-
-/* The maximum and minimum values for the integer type T. These
+#define TYPE_SIGNED(t) (! ((t) 0 < (t) -1))
+
+/* Return 1 if the integer expression E, after integer promotion, has
+ a signed type. E should not have side effects. */
+#define _GL_INT_SIGNED(e) (_GL_INT_CONVERT (e, -1) < 0)
+
+
+/* Minimum and maximum values for integer types and expressions. These
macros have undefined behavior if T is signed and has padding bits.
If this is a problem for you, please let us know how to fix it for
your host. */
-# define TYPE_MINIMUM(t) \
- ((t) (! TYPE_SIGNED (t) \
- ? (t) 0 \
- : TYPE_SIGNED_MAGNITUDE (t) \
- ? ~ (t) 0 \
+
+/* The maximum and minimum values for the integer type T. */
+#define TYPE_MINIMUM(t) \
+ ((t) (! TYPE_SIGNED (t) \
+ ? (t) 0 \
+ : TYPE_SIGNED_MAGNITUDE (t) \
+ ? ~ (t) 0 \
: ~ TYPE_MAXIMUM (t)))
-# define TYPE_MAXIMUM(t) \
- ((t) (! TYPE_SIGNED (t) \
- ? (t) -1 \
+#define TYPE_MAXIMUM(t) \
+ ((t) (! TYPE_SIGNED (t) \
+ ? (t) -1 \
: ((((t) 1 << (sizeof (t) * CHAR_BIT - 2)) - 1) * 2 + 1)))
-/* Return zero if T can be determined to be an unsigned type.
- Otherwise, return 1.
- When compiling with GCC, INT_STRLEN_BOUND uses this macro to obtain a
- tighter bound. Otherwise, it overestimates the true bound by one byte
- when applied to unsigned types of size 2, 4, 16, ... bytes.
- The symbol signed_type_or_expr__ is private to this header file. */
-# if __GNUC__ >= 2
-# define signed_type_or_expr__(t) TYPE_SIGNED (__typeof__ (t))
-# else
-# define signed_type_or_expr__(t) 1
-# endif
+/* The maximum and minimum values for the type of the expression E,
+ after integer promotion. E should not have side effects. */
+#define _GL_INT_MINIMUM(e) \
+ (_GL_INT_SIGNED (e) \
+ ? - _GL_INT_TWOS_COMPLEMENT (e) - _GL_SIGNED_INT_MAXIMUM (e) \
+ : _GL_INT_CONVERT (e, 0))
+#define _GL_INT_MAXIMUM(e) \
+ (_GL_INT_SIGNED (e) \
+ ? _GL_SIGNED_INT_MAXIMUM (e) \
+ : _GL_INT_CONVERT (e, -1))
+#define _GL_SIGNED_INT_MAXIMUM(e) \
+ (((_GL_INT_CONVERT (e, 1) << (sizeof ((e) + 0) * CHAR_BIT - 2)) - 1) * 2 + 1)
+
+
+/* Return 1 if the __typeof__ keyword works. This could be done by
+ 'configure', but for now it's easier to do it by hand. */
+#if 2 <= __GNUC__ || 0x5110 <= __SUNPRO_C
+# define _GL_HAVE___TYPEOF__ 1
+#else
+# define _GL_HAVE___TYPEOF__ 0
+#endif
+
+/* Return 1 if the integer type or expression T might be signed. Return 0
+ if it is definitely unsigned. This macro does not evaluate its argument,
+ and expands to an integer constant expression. */
+#if _GL_HAVE___TYPEOF__
+# define _GL_SIGNED_TYPE_OR_EXPR(t) TYPE_SIGNED (__typeof__ (t))
+#else
+# define _GL_SIGNED_TYPE_OR_EXPR(t) 1
+#endif
/* Bound on length of the string representing an unsigned integer
value representable in B bits. log10 (2.0) < 146/485. The
smallest value of B where this bound is not tight is 2621. */
-# define INT_BITS_STRLEN_BOUND(b) (((b) * 146 + 484) / 485)
+#define INT_BITS_STRLEN_BOUND(b) (((b) * 146 + 484) / 485)
/* Bound on length of the string representing an integer type or expression T.
Subtract 1 for the sign bit if T is signed, and then add 1 more for
- a minus sign if needed. */
-# define INT_STRLEN_BOUND(t) \
- (INT_BITS_STRLEN_BOUND (sizeof (t) * CHAR_BIT - signed_type_or_expr__ (t)) \
- + signed_type_or_expr__ (t))
+ a minus sign if needed.
+
+ Because _GL_SIGNED_TYPE_OR_EXPR sometimes returns 0 when its argument is
+ signed, this macro may overestimate the true bound by one byte when
+ applied to unsigned types of size 2, 4, 16, ... bytes. */
+#define INT_STRLEN_BOUND(t) \
+ (INT_BITS_STRLEN_BOUND (sizeof (t) * CHAR_BIT \
+ - _GL_SIGNED_TYPE_OR_EXPR (t)) \
+ + _GL_SIGNED_TYPE_OR_EXPR (t))
/* Bound on buffer size needed to represent an integer type or expression T,
including the terminating null. */
-# define INT_BUFSIZE_BOUND(t) (INT_STRLEN_BOUND (t) + 1)
-
-#endif /* GL_INTPROPS_H */
+#define INT_BUFSIZE_BOUND(t) (INT_STRLEN_BOUND (t) + 1)
+
+
+/* Range overflow checks.
+
+ The INT_<op>_RANGE_OVERFLOW macros return 1 if the corresponding C
+ operators might not yield numerically correct answers due to
+ arithmetic overflow. They do not rely on undefined or
+ implementation-defined behavior. Their implementations are simple
+ and straightforward, but they are a bit harder to use than the
+ INT_<op>_OVERFLOW macros described below.
+
+ Example usage:
+
+ long int i = ...;
+ long int j = ...;
+ if (INT_MULTIPLY_RANGE_OVERFLOW (i, j, LONG_MIN, LONG_MAX))
+ printf ("multiply would overflow");
+ else
+ printf ("product is %ld", i * j);
+
+ Restrictions on *_RANGE_OVERFLOW macros:
+
+ These macros do not check for all possible numerical problems or
+ undefined or unspecified behavior: they do not check for division
+ by zero, for bad shift counts, or for shifting negative numbers.
+
+ These macros may evaluate their arguments zero or multiple times,
+ so the arguments should not have side effects. The arithmetic
+ arguments (including the MIN and MAX arguments) must be of the same
+ integer type after the usual arithmetic conversions, and the type
+ must have minimum value MIN and maximum MAX. Unsigned types should
+ use a zero MIN of the proper type.
+
+ These macros are tuned for constant MIN and MAX. For commutative
+ operations such as A + B, they are also tuned for constant B. */
+
+/* Return 1 if A + B would overflow in [MIN,MAX] arithmetic.
+ See above for restrictions. */
+#define INT_ADD_RANGE_OVERFLOW(a, b, min, max) \
+ ((b) < 0 \
+ ? (a) < (min) - (b) \
+ : (max) - (b) < (a))
+
+/* Return 1 if A - B would overflow in [MIN,MAX] arithmetic.
+ See above for restrictions. */
+#define INT_SUBTRACT_RANGE_OVERFLOW(a, b, min, max) \
+ ((b) < 0 \
+ ? (max) + (b) < (a) \
+ : (a) < (min) + (b))
+
+/* Return 1 if - A would overflow in [MIN,MAX] arithmetic.
+ See above for restrictions. */
+#define INT_NEGATE_RANGE_OVERFLOW(a, min, max) \
+ ((min) < 0 \
+ ? (a) < - (max) \
+ : 0 < (a))
+
+/* Return 1 if A * B would overflow in [MIN,MAX] arithmetic.
+ See above for restrictions. */
+#define INT_MULTIPLY_RANGE_OVERFLOW(a, b, min, max) \
+ ((b) < 0 \
+ ? ((a) < 0 \
+ ? (a) < (max) / (b) \
+ : (b) < -1 && (min) / (b) < (a)) \
+ : (0 < (b) \
+ && ((a) < 0 \
+ ? (a) < (min) / (b) \
+ : (max) / (b) < (a))))
+
+/* Return 1 if A / B would overflow in [MIN,MAX] arithmetic.
+ See above for restrictions. Do not check for division by zero. */
+#define INT_DIVIDE_RANGE_OVERFLOW(a, b, min, max) \
+ ((min) < 0 && (b) == -1 && (a) < - (max))
+
+/* Return 1 if A % B would overflow in [MIN,MAX] arithmetic.
+ See above for restrictions. Do not check for division by zero.
+ Mathematically, % should never overflow, but on x86-like hosts
+ INT_MIN % -1 traps, and the C standard permits this, so treat this
+ as an overflow too. */
+#define INT_REMAINDER_RANGE_OVERFLOW(a, b, min, max) \
+ INT_DIVIDE_RANGE_OVERFLOW (a, b, min, max)
+
+/* Return 1 if A << B would overflow in [MIN,MAX] arithmetic.
+ See above for restrictions. Here, MIN and MAX are for A only, and B need
+ not be of the same type as the other arguments. The C standard says that
+ behavior is undefined for shifts unless 0 <= B < wordwidth, and that when
+ A is negative then A << B has undefined behavior and A >> B has
+ implementation-defined behavior, but do not check these other
+ restrictions. */
+#define INT_LEFT_SHIFT_RANGE_OVERFLOW(a, b, min, max) \
+ ((a) < 0 \
+ ? (a) < (min) >> (b) \
+ : (max) >> (b) < (a))
+
+
+/* The _GL*_OVERFLOW macros have the same restrictions as the
+ *_RANGE_OVERFLOW macros, except that they do not assume that operands
+ (e.g., A and B) have the same type as MIN and MAX. Instead, they assume
+ that the result (e.g., A + B) has that type. */
+#define _GL_ADD_OVERFLOW(a, b, min, max) \
+ ((min) < 0 ? INT_ADD_RANGE_OVERFLOW (a, b, min, max) \
+ : (a) < 0 ? (b) <= (a) + (b) \
+ : (b) < 0 ? (a) <= (a) + (b) \
+ : (a) + (b) < (b))
+#define _GL_SUBTRACT_OVERFLOW(a, b, min, max) \
+ ((min) < 0 ? INT_SUBTRACT_RANGE_OVERFLOW (a, b, min, max) \
+ : (a) < 0 ? 1 \
+ : (b) < 0 ? (a) - (b) <= (a) \
+ : (a) < (b))
+#define _GL_MULTIPLY_OVERFLOW(a, b, min, max) \
+ (((min) == 0 && (((a) < 0 && 0 < (b)) || ((b) < 0 && 0 < (a)))) \
+ || INT_MULTIPLY_RANGE_OVERFLOW (a, b, min, max))
+#define _GL_DIVIDE_OVERFLOW(a, b, min, max) \
+ ((min) < 0 ? (b) == _GL_INT_CONVERT (min, -1) && (a) < - (max) \
+ : (a) < 0 ? (b) <= (a) + (b) - 1 \
+ : (b) < 0 && (a) + (b) <= (a))
+#define _GL_REMAINDER_OVERFLOW(a, b, min, max) \
+ ((min) < 0 ? (b) == _GL_INT_CONVERT (min, -1) && (a) < - (max) \
+ : (a) < 0 ? (a) % (b) != ((max) - (b) + 1) % (b) \
+ : (b) < 0 && ! _GL_UNSIGNED_NEG_MULTIPLE (a, b, max))
+
+/* Return a nonzero value if A is a mathematical multiple of B, where
+ A is unsigned, B is negative, and MAX is the maximum value of A's
+ type. A's type must be the same as (A % B)'s type. Normally (A %
+ -B == 0) suffices, but things get tricky if -B would overflow. */
+#define _GL_UNSIGNED_NEG_MULTIPLE(a, b, max) \
+ (((b) < -_GL_SIGNED_INT_MAXIMUM (b) \
+ ? (_GL_SIGNED_INT_MAXIMUM (b) == (max) \
+ ? (a) \
+ : (a) % (_GL_INT_CONVERT (a, _GL_SIGNED_INT_MAXIMUM (b)) + 1)) \
+ : (a) % - (b)) \
+ == 0)
+
+
+/* Integer overflow checks.
+
+ The INT_<op>_OVERFLOW macros return 1 if the corresponding C operators
+ might not yield numerically correct answers due to arithmetic overflow.
+ They work correctly on all known practical hosts, and do not rely
+ on undefined behavior due to signed arithmetic overflow.
+
+ Example usage:
+
+ long int i = ...;
+ long int j = ...;
+ if (INT_MULTIPLY_OVERFLOW (i, j))
+ printf ("multiply would overflow");
+ else
+ printf ("product is %ld", i * j);
+
+ These macros do not check for all possible numerical problems or
+ undefined or unspecified behavior: they do not check for division
+ by zero, for bad shift counts, or for shifting negative numbers.
+
+ These macros may evaluate their arguments zero or multiple times, so the
+ arguments should not have side effects.
+
+ These macros are tuned for their last argument being a constant.
+
+ Return 1 if the integer expressions A * B, A - B, -A, A * B, A / B,
+ A % B, and A << B would overflow, respectively. */
+
+#define INT_ADD_OVERFLOW(a, b) \
+ _GL_BINARY_OP_OVERFLOW (a, b, _GL_ADD_OVERFLOW)
+#define INT_SUBTRACT_OVERFLOW(a, b) \
+ _GL_BINARY_OP_OVERFLOW (a, b, _GL_SUBTRACT_OVERFLOW)
+#define INT_NEGATE_OVERFLOW(a) \
+ INT_NEGATE_RANGE_OVERFLOW (a, _GL_INT_MINIMUM (a), _GL_INT_MAXIMUM (a))
+#define INT_MULTIPLY_OVERFLOW(a, b) \
+ _GL_BINARY_OP_OVERFLOW (a, b, _GL_MULTIPLY_OVERFLOW)
+#define INT_DIVIDE_OVERFLOW(a, b) \
+ _GL_BINARY_OP_OVERFLOW (a, b, _GL_DIVIDE_OVERFLOW)
+#define INT_REMAINDER_OVERFLOW(a, b) \
+ _GL_BINARY_OP_OVERFLOW (a, b, _GL_REMAINDER_OVERFLOW)
+#define INT_LEFT_SHIFT_OVERFLOW(a, b) \
+ INT_LEFT_SHIFT_RANGE_OVERFLOW (a, b, \
+ _GL_INT_MINIMUM (a), _GL_INT_MAXIMUM (a))
+
+/* Return 1 if the expression A <op> B would overflow,
+ where OP_RESULT_OVERFLOW (A, B, MIN, MAX) does the actual test,
+ assuming MIN and MAX are the minimum and maximum for the result type.
+
+ This macro assumes that A | B is a valid integer if both A and B are,
+ which is true of all known practical hosts. If this is a problem
+ for you, please let us know how to fix it for your host. */
+#define _GL_BINARY_OP_OVERFLOW(a, b, op_result_overflow) \
+ op_result_overflow (a, b, \
+ _GL_INT_MINIMUM ((a) | (b)), \
+ _GL_INT_MAXIMUM ((a) | (b)))
+
+#endif /* _GL_INTPROPS_H */
=== modified file 'lib/unistd.in.h'
--- lib/unistd.in.h 2011-04-18 04:03:18 +0000
+++ lib/unistd.in.h 2011-05-16 00:51:54 +0000
@@ -871,6 +871,22 @@
#endif
+#if @GNULIB_GROUP_MEMBER@
+/* Determine whether group id is in calling user's group list. */
+# if address@hidden@
+_GL_FUNCDECL_SYS (group_member, int, (gid_t gid));
+# endif
+_GL_CXXALIAS_SYS (group_member, int, (gid_t gid));
+_GL_CXXALIASWARN (group_member);
+#elif defined GNULIB_POSIXCHECK
+# undef group_member
+# if HAVE_RAW_DECL_GROUP_MEMBER
+_GL_WARN_ON_USE (group_member, "group_member is unportable - "
+ "use gnulib module group-member for portability");
+# endif
+#endif
+
+
#if @GNULIB_LCHOWN@
/* Change the owner of FILE to UID (if UID is not -1) and the group of FILE
to GID (if GID is not -1). Do not follow symbolic links.
=== modified file 'm4/unistd_h.m4'
--- m4/unistd_h.m4 2011-04-18 04:03:18 +0000
+++ m4/unistd_h.m4 2011-05-16 00:51:54 +0000
@@ -1,4 +1,4 @@
-# unistd_h.m4 serial 55
+# unistd_h.m4 serial 56
dnl Copyright (C) 2006-2011 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
@@ -36,8 +36,8 @@
]], [chown dup2 dup3 environ euidaccess faccessat fchdir fchownat
fsync ftruncate getcwd getdomainname getdtablesize getgroups
gethostname getlogin getlogin_r getpagesize getusershell setusershell
- endusershell lchown link linkat lseek pipe pipe2 pread pwrite readlink
- readlinkat rmdir sleep symlink symlinkat ttyname_r unlink unlinkat
+ endusershell group_member lchown link linkat lseek pipe pipe2 pread pwrite
+ readlink readlinkat rmdir sleep symlink symlinkat ttyname_r unlink unlinkat
usleep])
])
@@ -72,6 +72,7 @@
GNULIB_GETLOGIN_R=0; AC_SUBST([GNULIB_GETLOGIN_R])
GNULIB_GETPAGESIZE=0; AC_SUBST([GNULIB_GETPAGESIZE])
GNULIB_GETUSERSHELL=0; AC_SUBST([GNULIB_GETUSERSHELL])
+ GNULIB_GROUP_MEMBER=0; AC_SUBST([GNULIB_GROUP_MEMBER])
GNULIB_LCHOWN=0; AC_SUBST([GNULIB_LCHOWN])
GNULIB_LINK=0; AC_SUBST([GNULIB_LINK])
GNULIB_LINKAT=0; AC_SUBST([GNULIB_LINKAT])
@@ -110,6 +111,7 @@
HAVE_GETHOSTNAME=1; AC_SUBST([HAVE_GETHOSTNAME])
HAVE_GETLOGIN=1; AC_SUBST([HAVE_GETLOGIN])
HAVE_GETPAGESIZE=1; AC_SUBST([HAVE_GETPAGESIZE])
+ HAVE_GROUP_MEMBER=1; AC_SUBST([HAVE_GROUP_MEMBER])
HAVE_LCHOWN=1; AC_SUBST([HAVE_LCHOWN])
HAVE_LINK=1; AC_SUBST([HAVE_LINK])
HAVE_LINKAT=1; AC_SUBST([HAVE_LINKAT])
--- End Message ---