dps_snprintf_oflow
, 

2002年10月10日

Duncan Simpson <dps@io.stargate.co.uk>

AllPermissive
Copying and distribution of this file, with or without modification, are permitted in any medium without royalty provided the copyright notice and this notice are preserved. Users of this software should generally follow the principles of the MIT License includings its disclaimer.

cryp.to ac-archive's C Support (released)

Checks whether snprintf ignores the value of n or not and defines HAVE_SNPRINTF_BUG if it does.

AC_DEFUN([dps_snprintf_oflow],
[AC_MSG_CHECKING(whether snprintf ignores n)
AC_CACHE_VAL(dps_cv_snprintf_bug,
[AC_TRY_RUN(
changequote(<<, >>)dnl
<<#include <stdio.h>
#ifndef HAVE_SNPRINTF
#ifdef HAVE_VSNPRINTF
#include "vsnprintf.h"
#else /* not HAVE_VSNPRINTF */
#include "vsnprintf.c"
#endif /* HAVE_VSNPRINTF */
#endif /* HAVE_SNPRINTF */
int main(void)
{
char ovbuf[7];
int i;
for (i=0; i<7; i++) ovbuf[i]='x';
snprintf(ovbuf, 4,"foo%s", "bar");
if (ovbuf[5]!='x') exit(1);
snprintf(ovbuf, 4,"foo%d", 666);
if (ovbuf[5]!='x') exit(1);
exit(0);
} >>
changequote([, ]), dps_cv_snprintf_bug=0, dps_cv_snprintf_bug=1,
dps_cv_snprintf_bug=2)])
if test $dps_cv_snprintf_bug -eq 0; then
 AC_MSG_RESULT([no, snprintf is ok])
else if test $dps_cv_snprintf_bug -eq 1; then
 AC_MSG_RESULT([yes, snprintf is broken])
 AC_DEFINE(HAVE_SNPRINTF_BUG,1)
else
 AC_MSG_RESULT([unknown, assuming yes])
 AC_DEFINE(HAVE_SNPRINTF_BUG,1)
fi; fi])