scanf and "-0x", "-nan", "inf"
Eric Blake
ebb9@byu.net
Thu May 24 12:35:00 GMT 2007
Jeff Johnston <jjohnstn <at> redhat.com> writes:
>
> Ok.
>
Further testing hammered out a couple of issues in my earlier posting - ungetc
is not reentrant, so I swapped to _ungetc_r. Also, POSIX requires that read
failure return EOF no matter what, but we were sometimes returning with a non-
negative result even after ferror() was set because of a read error after a
match. Here's what I committed:
2007-05-23 Eric Blake <ebb9@byu.net>
* libc/stdio/vfprintf.c (_VFPRINTF_R): Don't truncate %p when
sizeof(void*) is 8 but sizeof(long) is 4.
* libc/stdio/vfscanf.c (__SVFSCANF_R): Likewise. Fix %i scanning
of "-0x". Support "-nan" and "inf" for %e. Audit usage of ungetc
to fix reentrancy and bug on encoding error in multibyte locales.
Always return EOF on read error.
Index: libc/stdio/vfprintf.c
===================================================================
RCS file: /cvs/src/src/newlib/libc/stdio/vfprintf.c,v
retrieving revision 1.61
diff -u -p -r1.61 vfprintf.c
--- libc/stdio/vfprintf.c 23 May 2007 20:36:28 -0000 1.61
+++ libc/stdio/vfprintf.c 24 May 2007 04:17:01 -0000
@@ -1017,7 +1017,7 @@ reswitch: switch (ch) {
* -- ANSI X3J11
*/
/* NOSTRICT */
- _uquad = (u_long)(unsigned _POINTER_INT)GET_ARG (N, ap,
void_ptr_t);
+ _uquad = (uintptr_t) GET_ARG (N, ap, void_ptr_t);
base = HEX;
xdigs = "0123456789abcdef";
flags |= HEXPREFIX;
Index: libc/stdio/vfscanf.c
===================================================================
RCS file: /cvs/src/src/newlib/libc/stdio/vfscanf.c,v
retrieving revision 1.37
diff -u -p -r1.37 vfscanf.c
--- libc/stdio/vfscanf.c 23 May 2007 20:36:28 -0000 1.37
+++ libc/stdio/vfscanf.c 24 May 2007 04:17:01 -0000
@@ -825,10 +825,10 @@ _DEFUN(__SVFSCANF_R, (rptr, fp, fmt0, ap
*wcp = L'\0';
if (mbslen != (size_t)-2) /* Incomplete sequence */
{
- if (iswspace(*wcp))
+ if (iswspace(*wcp))
{
while (n != 0)
- ungetc (buf[--n], fp);
+ _ungetc_r (rptr, (unsigned char) buf[--n], fp);
break;
}
nread += n;
@@ -987,15 +987,15 @@ _DEFUN(__SVFSCANF_R, (rptr, fp, fmt0, ap
}
break;
- /* x ok iff flag still set & 2nd char */
+ /* x ok iff flag still set & single 0 seen */
case 'x':
case 'X':
- if (flags & PFXOK && p == buf + 1)
+ if ((flags & (PFXOK | NZDIGITS)) == PFXOK)
{
base = 16;/* if %i */
flags &= ~PFXOK;
/* We must reset the NZDIGITS and NDIGITS
- flags that would have been unset by seeing
+ flags that would have been unset by seeing
the zero that preceded the X or x. */
flags |= NZDIGITS | NDIGITS;
goto ok;
@@ -1024,18 +1024,16 @@ _DEFUN(__SVFSCANF_R, (rptr, fp, fmt0, ap
* If we had only a sign, it is no good; push back the sign.
* If the number ends in `x', it was [sign] '0' 'x', so push back
* the x and treat it as [sign] '0'.
+ * Use of ungetc here and below assumes ASCII encoding; we are only
+ * pushing back 7-bit characters, so casting to unsigned char is
+ * not necessary.
*/
if (flags & NDIGITS)
{
if (p > buf)
- _CAST_VOID ungetc (*(u_char *)-- p, fp);
- goto match_failure;
- }
- c = ((u_char *) p)[-1];
- if (c == 'x' || c == 'X')
- {
- --p;
- /*(void)*/ ungetc (c, fp);
+ _ungetc_r (rptr, *--p, fp); /* [-+xX] */
+ if (p == buf)
+ goto match_failure;
}
if ((flags & SUPPRESS) == 0)
{
@@ -1044,7 +1042,19 @@ _DEFUN(__SVFSCANF_R, (rptr, fp, fmt0, ap
*p = 0;
res = (*ccfn) (rptr, buf, (char **) NULL, base);
if (flags & POINTER)
- *(GET_ARG (N, ap, _PTR *)) = (_PTR) (unsigned _POINTER_INT) res;
+ {
+ void **vp = GET_ARG (N, ap, void **);
+#ifndef _NO_LONGLONG
+ if (sizeof (uintptr_t) > sizeof (u_long))
+ {
+ u_long_long resll;
+ resll = _strtoull_r (rptr, buf, (char **) NULL, base);
+ *vp = (void *) (uintptr_t) resll;
+ }
+ else
+#endif /* !_NO_LONGLONG */
+ *vp = (void *) (uintptr_t) res;
+ }
#ifdef _WANT_IO_C99_FORMATS
else if (flags & CHAR)
{
@@ -1096,7 +1106,8 @@ _DEFUN(__SVFSCANF_R, (rptr, fp, fmt0, ap
long zeroes, exp_adjust;
char *exp_start = NULL;
unsigned width_left = 0;
- int nancount = 0;
+ char nancount = 0;
+ char infcount = 0;
#ifdef hardway
if (width == 0 || width > sizeof (buf) - 1)
#else
@@ -1141,7 +1152,7 @@ _DEFUN(__SVFSCANF_R, (rptr, fp, fmt0, ap
case '7':
case '8':
case '9':
- if (nancount == 0)
+ if (nancount + infcount == 0)
{
flags &= ~(SIGNOK | NDIGITS);
goto fok;
@@ -1159,18 +1170,23 @@ _DEFUN(__SVFSCANF_R, (rptr, fp, fmt0, ap
case 'n':
case 'N':
if (nancount == 0
- && (flags & (SIGNOK | NDIGITS | DPTOK | EXPOK)) ==
- (SIGNOK | NDIGITS | DPTOK | EXPOK))
+ && (flags & (NDIGITS | DPTOK | EXPOK)) ==
+ (NDIGITS | DPTOK | EXPOK))
{
flags &= ~(SIGNOK | DPTOK | EXPOK | NDIGITS);
nancount = 1;
goto fok;
}
- else if (nancount == 2)
+ if (nancount == 2)
{
nancount = 3;
goto fok;
}
+ if (infcount == 1 || infcount == 4)
+ {
+ infcount++;
+ goto fok;
+ }
break;
case 'a':
case 'A':
@@ -1180,6 +1196,46 @@ _DEFUN(__SVFSCANF_R, (rptr, fp, fmt0, ap
goto fok;
}
break;
+ case 'i':
+ case 'I':
+ if (infcount == 0
+ && (flags & (NDIGITS | DPTOK | EXPOK)) ==
+ (NDIGITS | DPTOK | EXPOK))
+ {
+ flags &= ~(SIGNOK | DPTOK | EXPOK | NDIGITS);
+ infcount = 1;
+ goto fok;
+ }
+ if (infcount == 3 || infcount == 5)
+ {
+ infcount++;
+ goto fok;
+ }
+ break;
+ case 'f':
+ case 'F':
+ if (infcount == 2)
+ {
+ infcount = 3;
+ goto fok;
+ }
+ break;
+ case 't':
+ case 'T':
+ if (infcount == 6)
+ {
+ infcount = 7;
+ goto fok;
+ }
+ break;
+ case 'y':
+ case 'Y':
+ if (infcount == 7)
+ {
+ infcount = 8;
+ goto fok;
+ }
+ break;
case '.':
if (flags & DPTOK)
{
@@ -1212,7 +1268,7 @@ _DEFUN(__SVFSCANF_R, (rptr, fp, fmt0, ap
*p++ = c;
fskip:
width--;
- ++nread;
+ ++nread;
if (--fp->_r > 0)
fp->_p++;
else
@@ -1221,24 +1277,48 @@ _DEFUN(__SVFSCANF_R, (rptr, fp, fmt0, ap
}
if (zeroes)
flags &= ~NDIGITS;
- /* We may have a 'N' or possibly even a 'Na' as the start of 'NaN',
- only to run out of chars before it was complete (or having
- encountered a non- matching char). So check here if we have an
- outstanding nancount, and if so put back the chars we did
- swallow and treat as a failed match. */
- if (nancount && nancount != 3)
- {
- /* Ok... what are we supposed to do in the event that the
- __srefill call above was triggered in the middle of the partial
- 'NaN' and so we can't put it all back? */
- while (nancount-- && (p > buf))
- {
- ungetc (*(u_char *)--p, fp);
- --nread;
- }
- goto match_failure;
- }
- /*
+ /* We may have a 'N' or possibly even [sign] 'N' 'a' as the
+ start of 'NaN', only to run out of chars before it was
+ complete (or having encountered a non-matching char). So
+ check here if we have an outstanding nancount, and if so
+ put back the chars we did swallow and treat as a failed
+ match.
+
+ FIXME - we still don't handle NAN([0xdigits]). */
+ if (nancount - 1U < 2U) /* nancount && nancount < 3 */
+ {
+ /* Newlib's ungetc works even if we called __srefill in
+ the middle of a partial parse, but POSIX does not
+ guarantee that in all implementations of ungetc. */
+ while (p > buf)
+ {
+ _ungetc_r (rptr, *--p, fp); /* [-+nNaA] */
+ --nread;
+ }
+ goto match_failure;
+ }
+ /* Likewise for 'inf' and 'infinity'. But be careful that
+ 'infinite' consumes only 3 characters, leaving the stream
+ at the second 'i'. */
+ if (infcount - 1U < 7U) /* infcount && infcount < 8 */
+ {
+ if (infcount >= 3) /* valid 'inf', but short of 'infinity' */
+ while (infcount-- > 3)
+ {
+ _ungetc_r (rptr, *--p, fp); /* [iInNtT] */
+ --nread;
+ }
+ else
+ {
+ while (p > buf)
+ {
+ _ungetc_r (rptr, *--p, fp); /* [-+iInN] */
+ --nread;
+ }
+ goto match_failure;
+ }
+ }
+ /*
* If no digits, might be missing exponent digits
* (just give back the exponent) or might be missing
* regular digits, but had sign and/or decimal point.
@@ -1249,22 +1329,22 @@ _DEFUN(__SVFSCANF_R, (rptr, fp, fmt0, ap
{
/* no digits at all */
while (p > buf)
- {
- ungetc (*(u_char *)--p, fp);
- --nread;
- }
+ {
+ _ungetc_r (rptr, *--p, fp); /* [-+.] */
+ --nread;
+ }
goto match_failure;
}
/* just a bad exponent (e and maybe sign) */
- c = *(u_char *)-- p;
- --nread;
+ c = *--p;
+ --nread;
if (c != 'e' && c != 'E')
{
- _CAST_VOID ungetc (c, fp); /* sign */
- c = *(u_char *)-- p;
- --nread;
+ _ungetc_r (rptr, c, fp); /* [-+] */
+ c = *--p;
+ --nread;
}
- _CAST_VOID ungetc (c, fp);
+ _ungetc_r (rptr, c, fp); /* [eE] */
}
if ((flags & SUPPRESS) == 0)
{
@@ -1332,10 +1412,15 @@ _DEFUN(__SVFSCANF_R, (rptr, fp, fmt0, ap
}
}
input_failure:
+ /* On read failure, return EOF failure regardless of matches; errno
+ should have been set prior to here. On EOF failure (including
+ invalid format string), return EOF if no matches yet, else number
+ of matches made prior to failure. */
_funlockfile (fp);
- return nassigned ? nassigned : -1;
+ return nassigned && !(fp->_flags & __SERR) ? nassigned : EOF;
match_failure:
all_done:
+ /* Return number of matches, which can be 0 on match failure. */
_funlockfile (fp);
return nassigned;
}
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