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Merge: doprnt: Omit useless test; int overflow check (Bug#8545).

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Paul Eggert 2011-04-28 15:06:00 -07:00
commit a8346e4904
2 changed files with 22 additions and 7 deletions
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5
src/ChangeLog
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@ -1,3 +1,8 @@
2011-04-28 Paul Eggert <eggert@cs.ucla.edu>
* doprnt.c (doprnt): Omit useless test; int overflow check (Bug#8545).
(SIZE_MAX): Move defn after all includes, as they might #define it.
2011-04-28 Juanma Barranquero <lekktu@gmail.com>
* w32.c (init_environment): Warn about defaulting HOME to C:\.

24
src/doprnt.c
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@ -70,7 +70,9 @@ along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */
%<flags><width><precision><length>character
where flags is [+ -0], width is [0-9]+, precision is .[0-9]+, and length
modifier is empty or l or ll.
is empty or l or ll. Also, %% in a format stands for a single % in the
output. A % that does not introduce a valid %-sequence causes
undefined behavior.
The + flag character inserts a + before any positive number, while a space
inserts a space before any positive number; these flags only affect %d, %o,
@ -111,9 +113,6 @@ along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */
#include <unistd.h>
#include <limits.h>
#ifndef SIZE_MAX
# define SIZE_MAX ((size_t) -1)
#endif
#include "lisp.h"
@ -122,14 +121,21 @@ along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */
another macro. */
#include "character.h"
#ifndef SIZE_MAX
# define SIZE_MAX ((size_t) -1)
#endif
#ifndef DBL_MAX_10_EXP
#define DBL_MAX_10_EXP 308 /* IEEE double */
#endif
/* Generate output from a format-spec FORMAT,
terminated at position FORMAT_END.
(*FORMAT_END is not part of the format, but must exist and be readable.)
Output goes in BUFFER, which has room for BUFSIZE chars.
If the output does not fit, truncate it to fit.
BUFSIZE must be positive. If the output does not fit, truncate it
to fit and return BUFSIZE - 1; if this truncates a multibyte
sequence, store '\0' into the sequence's first byte.
Returns the number of bytes stored into BUFFER, excluding
the terminating null byte. Output is always null-terminated.
String arguments are passed as C strings.
@ -198,8 +204,12 @@ doprnt (char *buffer, register size_t bufsize, const char *format,
while (fmt < format_end
&& '0' <= fmt[1] && fmt[1] <= '9')
{
if (n >= SIZE_MAX / 10
|| n * 10 > SIZE_MAX - (fmt[1] - '0'))
/* Avoid size_t overflow. Avoid int overflow too, as
many sprintfs mishandle widths greater than INT_MAX.
This test is simple but slightly conservative: e.g.,
(INT_MAX - INT_MAX % 10) is reported as an overflow
even when it's not. */
if (n >= min (INT_MAX, SIZE_MAX) / 10)
error ("Format width or precision too large");
n = n * 10 + fmt[1] - '0';
*string++ = *++fmt;