Do not set errno for overflowing NaN payload in strtod/nan (bug 32045)

As reported in bug 32045, it's incorrect for strtod/nan functions to
set errno based on overflowing payload (strtod should only set errno
for overflow / underflow of its actual result, and potentially if
nothing in the string can be parsed as a number at all; nan should be
a pure function that never sets it).  Save and restore errno around
the internal strtoull call and add associated test coverage.

Tested for x86_64.

(cherry picked from commit 64f62c47e9)
This commit is contained in:
Joseph Myers 2024-09-04 13:21:23 +00:00 committed by Arjun Shankar
parent 63bcc01744
commit 6624318c89
3 changed files with 57 additions and 0 deletions

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@ -462,6 +462,7 @@ CFLAGS-test-flt-eval-method.c += -fexcess-precision=standard
CFLAGS-test-fe-snans-always-signal.c += $(config-cflags-signaling-nans)
CFLAGS-test-nan-const.c += -fno-builtin
CFLAGS-test-nan-payload.c += -fno-builtin
include ../Rules

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@ -18,6 +18,7 @@
#define _LIBC_TEST 1
#define __STDC_WANT_IEC_60559_TYPES_EXT__
#include <errno.h>
#include <float.h>
#include <math.h>
#include <stdio.h>
@ -82,6 +83,26 @@
} \
while (0)
#define CLEAR_ERRNO \
do \
{ \
errno = 12345; \
} \
while (0)
#define CHECK_ERRNO(TYPE, A) \
do \
{ \
if (errno == 12345) \
puts ("PASS: " #TYPE " " #A " errno"); \
else \
{ \
puts ("FAIL: " #TYPE " " #A " errno"); \
result = 1; \
} \
} \
while (0)
/* Cannot test payloads by memcmp for formats where NaNs have padding
bits. */
#define CAN_TEST_EQ(MANT_DIG) ((MANT_DIG) != 64 && (MANT_DIG) != 106)
@ -89,26 +110,58 @@
#define RUN_TESTS(TYPE, SFUNC, FUNC, PLFUNC, MANT_DIG) \
do \
{ \
CLEAR_ERRNO; \
TYPE n123 = WRAP_NAN (FUNC, "123"); \
CHECK_ERRNO (TYPE, n123); \
CHECK_IS_NAN (TYPE, n123); \
CLEAR_ERRNO; \
TYPE s123 = WRAP_STRTO (SFUNC, "NAN(123)"); \
CHECK_ERRNO (TYPE, s123); \
CHECK_IS_NAN (TYPE, s123); \
CLEAR_ERRNO; \
TYPE n456 = WRAP_NAN (FUNC, "456"); \
CHECK_ERRNO (TYPE, n456); \
CHECK_IS_NAN (TYPE, n456); \
CLEAR_ERRNO; \
TYPE s456 = WRAP_STRTO (SFUNC, "NAN(456)"); \
CHECK_ERRNO (TYPE, s456); \
CHECK_IS_NAN (TYPE, s456); \
CLEAR_ERRNO; \
TYPE nh123 = WRAP_NAN (FUNC, "0x123"); \
CHECK_ERRNO (TYPE, nh123); \
CHECK_IS_NAN (TYPE, nh123); \
CLEAR_ERRNO; \
TYPE sh123 = WRAP_STRTO (SFUNC, "NAN(0x123)"); \
CHECK_ERRNO (TYPE, sh123); \
CHECK_IS_NAN (TYPE, sh123); \
CLEAR_ERRNO; \
TYPE n123x = WRAP_NAN (FUNC, "123)"); \
CHECK_ERRNO (TYPE, n123x); \
CHECK_IS_NAN (TYPE, n123x); \
CLEAR_ERRNO; \
TYPE nemp = WRAP_NAN (FUNC, ""); \
CHECK_ERRNO (TYPE, nemp); \
CHECK_IS_NAN (TYPE, nemp); \
CLEAR_ERRNO; \
TYPE semp = WRAP_STRTO (SFUNC, "NAN()"); \
CHECK_ERRNO (TYPE, semp); \
CHECK_IS_NAN (TYPE, semp); \
CLEAR_ERRNO; \
TYPE sx = WRAP_STRTO (SFUNC, "NAN"); \
CHECK_ERRNO (TYPE, sx); \
CHECK_IS_NAN (TYPE, sx); \
CLEAR_ERRNO; \
TYPE novf = WRAP_NAN (FUNC, "9999999999" \
"99999999999999999999" \
"9999999999"); \
CHECK_ERRNO (TYPE, novf); \
CHECK_IS_NAN (TYPE, novf); \
CLEAR_ERRNO; \
TYPE sovf = WRAP_STRTO (SFUNC, "NAN(9999999999" \
"99999999999999999999" \
"9999999999)"); \
CHECK_ERRNO (TYPE, sovf); \
CHECK_IS_NAN (TYPE, sovf); \
if (CAN_TEST_EQ (MANT_DIG)) \
CHECK_SAME_NAN (TYPE, n123, s123); \
CHECK_PAYLOAD (TYPE, PLFUNC, n123, 123); \

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@ -16,6 +16,7 @@
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <errno.h>
#include <ieee754.h>
#include <locale.h>
#include <math.h>
@ -50,7 +51,9 @@ STRTOD_NAN (const STRING_TYPE *str, STRING_TYPE **endptr, STRING_TYPE endc)
STRING_TYPE *endp;
unsigned long long int mant;
int save_errno = errno;
mant = STRTOULL (str, &endp, 0);
__set_errno (save_errno);
if (endp == cp)
SET_NAN_PAYLOAD (retval, mant);