With the register_printf_type/register_printf_modifier/register_printf_specifier
APIs the C library is just told the size of the argument and is provided with
a callback to fetch the argument from va_list using va_arg into C library provided
memory. The C library isn't told what alignment requirement it has, but we were
using direct load of a __float128 value from that memory which assumes
__alignof (__float128) alignment.
The following patch fixes that by using memcpy instead.
I haven't been able to reproduce an actual crash, tried
#include <quadmath.h>
#include <stdlib.h>
#include <stdio.h>
int main ()
{
__float128 r;
int prec = 20;
int width = 46;
char buf[128];
r = 2.0q;
r = sqrtq (r);
int n = quadmath_snprintf (buf, sizeof buf, "%+-#*.20Qe", width, r);
if ((size_t) n < sizeof buf)
printf ("%s\n", buf);
/* Prints: +1.41421356237309504880e+00 */
quadmath_snprintf (buf, sizeof buf, "%Qa", r);
if ((size_t) n < sizeof buf)
printf ("%s\n", buf);
/* Prints: 0x1.6a09e667f3bcc908b2fb1366ea96p+0 */
n = quadmath_snprintf (NULL, 0, "%+-#46.*Qe", prec, r);
if (n > -1)
{
char *str = malloc (n + 1);
if (str)
{
quadmath_snprintf (str, n + 1, "%+-#46.*Qe", prec, r);
printf ("%s\n", str);
/* Prints: +1.41421356237309504880e+00 */
}
free (str);
}
printf ("%+-#*.20Qe\n", width, r);
printf ("%Qa\n", r);
printf ("%+-#46.*Qe\n", prec, r);
printf ("%d %Qe %d %Qe %d %Qe\n", 1, r, 2, r, 3, r);
return 0;
}
In any case, I think memcpy for loading from it is right.
2024-04-03 Simon Chopin <simon.chopin@canonical.com>
Jakub Jelinek <jakub@redhat.com>
PR libquadmath/114533
* printf/printf_fp.c (__quadmath_printf_fp): Use memcpy to copy
__float128 out of args.
* printf/printf_fphex.c (__quadmath_printf_fphex): Likewise.
Signed-off-by: Simon Chopin <simon.chopin@canonical.com>
2012-11-23 Tobias Burnus <burnus@net-b.de>
Joseph Myers <joseph@codesourcery.com>
* quadmath-rounding-mode.h: New.
* printf/fpioconst.c: Update from GLIBC. Fix strtod rounding.
* printf/fpioconst.h: Ditto.
* printf/printf_fp.c (__quadmath_printf_fp): Update from GLIBC.
Make printf respect the rounding mode for decimal output.
* printf/printf_fphex.c (__quadmath_printf_fphex): Update from
GLIBC. Make printf respect the rounding mode for hex output.
* strtod/strtod_l.c: Update from GLIBC. Make strtod respect the
rounding mode. Fix strtod handling of underflow.
Co-Authored-By: Joseph Myers <joseph@codesourcery.com>
From-SVN: r193770
* printf/quadmath-printf.c: Also check __GLIBC__ when checking
whether workarounds for printf hook handling should be added.
* configure.ac: Check for locale.h too.
(USE_LOCALE_SUPPORT): Remove check.
(USE_NL_LANGINFO, USE_NL_LANGINFO_WC, USE_LOCALECONV): New checks.
(USE_I18_NUMBER_H): Check also for _NL_CTYPE_MB_CUR_MAX.
* printf/printf_fphex.c (__quadmath_printf_fphex): Use nl_langinfo
or localeconv for narrow version and nl_langinfo if USE_NL_LANGINFO_WC
for wide version.
* printf/quadmath-printf.h: Include locale.h if HAVE_LOCALE_H.
* printf/printf_fp.c (USE_I18N_NUMBER_H): Don't define to 0.
(__quadmath_printf_fp): Use nl_langinfo or localeconv for narrow
version and nl_langinfo if USE_NL_LANGINFO_WC for wide version.
Guard nl_langinfo (_NL_CTYPE_MB_CUR_MAX) use with
USE_I18N_NUMBER_H #ifdef.
* configure: Regenerated.
* config.h.in: Regenerated.
From-SVN: r170211
* configure.ac (HAVE_HIDDEN_VISIBILITY): Test with -Werror in CFLAGS.
* printf/printf_fp.c: Don't include <alloca.h>.
* printf/quadmath-printf.h (_itoa): Redefine to __quadmath_itoa.
* configure: Regenerated.
From-SVN: r170139
