Add __vfscanf_internal and __vfwscanf_internal with flags arguments.

There are two flags currently defined: SCANF_LDBL_IS_DBL is the mode
used by __nldbl_ scanf variants, and SCANF_ISOC99_A is the mode used
by __isoc99_ scanf variants.  In this patch, the new functions honor
these flag bits if they're set, but they still also look at the
corresponding bits of environmental state, and callers all pass zero.

The new functions do *not* have the "errp" argument possessed by
_IO_vfscanf and _IO_vfwscanf.  All internal callers passed NULL for
that argument.  External callers could theoretically exist, so I
preserved wrappers, but they are flagged as compat symbols and they
don't preserve the three-way distinction among types of errors that
was formerly exposed.  These functions probably should have been in
the list of deprecated _IO_ symbols in 2.27 NEWS -- they're not just
aliases for vfscanf and vfwscanf.

(It was necessary to introduce ldbl_compat_symbol for _IO_vfscanf.
Please check that part of the patch very carefully, I am still not
confident I understand all of the details of ldbl-opt.)

This patch also introduces helper inlines in libio/strfile.h that
encapsulate the process of initializing an _IO_strfile object for
reading.  This allows us to call __vfscanf_internal directly from
sscanf, and __vfwscanf_internal directly from swscanf, without
duplicating the initialization code.  (Previously, they called their
v-counterparts, but that won't work if we want to control *both* C99
mode and ldbl-is-dbl mode using the flags argument to__vfscanf_internal.)
It's still a little awkward, especially for wide strfiles, but it's
much better than what we had.

Tested for powerpc and powerpc64le.

9 files changed, 68 insertions, 30 deletions

diff --git a/libio/iovsscanf.c b/libio/iovsscanf.c
index e56ab8b..ee6a99e 100644
--- a/libio/iovsscanf.c
+++ b/libio/iovsscanf.c
@@ -24,22 +24,14 @@
    This exception applies to code released by its copyright holders
    in files containing the exception.  */
 
-#include "libioP.h"
 #include "strfile.h"
 
 int
 _IO_vsscanf (const char *string, const char *format, va_list args)
 {
-  int ret;
   _IO_strfile sf;
-#ifdef _IO_MTSAFE_IO
-  sf._sbf._f._lock = NULL;
-#endif
-  _IO_no_init (&sf._sbf._f, _IO_USER_LOCK, -1, NULL, NULL);
-  _IO_JUMPS (&sf._sbf) = &_IO_str_jumps;
-  _IO_str_init_static_internal (&sf, (char*)string, 0, NULL);
-  ret = _IO_vfscanf (&sf._sbf._f, format, args, NULL);
-  return ret;
+  FILE *f = _IO_strfile_read (&sf, string);
+  return __vfscanf_internal (f, format, args, 0);
 }
 ldbl_weak_alias (_IO_vsscanf, __vsscanf)
 ldbl_weak_alias (_IO_vsscanf, vsscanf)
diff --git a/libio/iovswscanf.c b/libio/iovswscanf.c
index 5bd1c88..cb9cbe1 100644
--- a/libio/iovswscanf.c
+++ b/libio/iovswscanf.c
@@ -24,24 +24,16 @@
    This exception applies to code released by its copyright holders
    in files containing the exception.  */
 
-#include "libioP.h"
-#include "strfile.h"
 #include <wchar.h>
+#include "strfile.h"
 
 int
 __vswscanf (const wchar_t *string, const wchar_t *format, va_list args)
 {
-  int ret;
   _IO_strfile sf;
   struct _IO_wide_data wd;
-#ifdef _IO_MTSAFE_IO
-  sf._sbf._f._lock = NULL;
-#endif
-  _IO_no_init (&sf._sbf._f, _IO_USER_LOCK, 0, &wd, &_IO_wstr_jumps);
-  _IO_fwide (&sf._sbf._f, 1);
-  _IO_wstr_init_static (&sf._sbf._f, (wchar_t *)string, 0, NULL);
-  ret = _IO_vfwscanf ((FILE *) &sf._sbf, format, args, NULL);
-  return ret;
+  FILE *f = _IO_strfile_readw (&sf, &wd, string);
+  return __vfwscanf_internal (f, format, args, 0);
 }
 libc_hidden_def (__vswscanf)
 ldbl_hidden_def (__vswscanf, vswscanf)
diff --git a/libio/libio.h b/libio/libio.h
index 00f9169..d4eba2d 100644
--- a/libio/libio.h
+++ b/libio/libio.h
@@ -321,7 +321,6 @@ libc_hidden_proto (_IO_padn)
 libc_hidden_proto (_IO_putc)
 libc_hidden_proto (_IO_sgetn)
 libc_hidden_proto (_IO_vfprintf)
-libc_hidden_proto (_IO_vfscanf)
 
 #ifdef _IO_MTSAFE_IO
 # undef _IO_peekc
diff --git a/libio/libioP.h b/libio/libioP.h
index df2633d..525dce1 100644
--- a/libio/libioP.h
+++ b/libio/libioP.h
@@ -704,6 +704,28 @@ extern off64_t _IO_seekpos_unlocked (FILE *, off64_t, int)
 
 #endif /* _G_HAVE_MMAP */
 
+/* Flags for __vfscanf_internal and __vfwscanf_internal.
+
+   SCANF_LDBL_IS_DBL indicates whether long double values are to be
+   handled as having the same format as double, in which case the flag
+   should be set to one, or as another format, otherwise.
+
+   SCANF_ISOC99_A, when set to one, indicates that the ISO C99 or POSIX
+   behavior of the scanf functions is to be used, i.e. automatic
+   allocation for input strings with %as, %aS and %a[, a GNU extension,
+   is disabled. This is the behavior that the __isoc99_scanf family of
+   functions use.  When the flag is set to zero, automatic allocation is
+   enabled.  */
+#define SCANF_LDBL_IS_DBL 0x0001
+#define SCANF_ISOC99_A    0x0002
+
+extern int __vfscanf_internal (FILE *fp, const char *format, va_list argp,
+			       unsigned int flags)
+  attribute_hidden;
+extern int __vfwscanf_internal (FILE *fp, const wchar_t *format, va_list argp,
+				unsigned int flags)
+  attribute_hidden;
+
 extern int _IO_vscanf (const char *, va_list) __THROW;
 
 #ifdef _IO_MTSAFE_IO
diff --git a/libio/strfile.h b/libio/strfile.h
index 75caac2..e51ac34 100644
--- a/libio/strfile.h
+++ b/libio/strfile.h
@@ -24,7 +24,9 @@
    This exception applies to code released by its copyright holders
    in files containing the exception.  */
 
-#include <stdio.h>
+#ifndef STRFILE_H_
+#define STRFILE_H_
+
 #include "libioP.h"
 
 typedef void *(*_IO_alloc_type) (size_t);
@@ -80,3 +82,32 @@ typedef struct
 } _IO_wstrnfile;
 
 extern const struct _IO_jump_t _IO_wstrn_jumps attribute_hidden;
+
+/* Initialize an _IO_strfile SF to read from narrow string STRING, and
+   return the corresponding FILE object.  It is not necessary to fclose
+   the FILE when it is no longer needed.  */
+static inline FILE *
+_IO_strfile_read (_IO_strfile *sf, const char *string)
+{
+  sf->_sbf._f._lock = NULL;
+  _IO_no_init (&sf->_sbf._f, _IO_USER_LOCK, -1, NULL, NULL);
+  _IO_JUMPS (&sf->_sbf) = &_IO_str_jumps;
+  _IO_str_init_static_internal (sf, (char*)string, 0, NULL);
+  return &sf->_sbf._f;
+}
+
+/* Initialize an _IO_strfile SF and _IO_wide_data WD to read from wide
+   string STRING, and return the corresponding FILE object.  It is not
+   necessary to fclose the FILE when it is no longer needed.  */
+static inline FILE *
+_IO_strfile_readw (_IO_strfile *sf, struct _IO_wide_data *wd,
+		   const wchar_t *string)
+{
+  sf->_sbf._f._lock = NULL;
+  _IO_no_init (&sf->_sbf._f, _IO_USER_LOCK, 0, wd, &_IO_wstr_jumps);
+  _IO_fwide (&sf->_sbf._f, 1);
+  _IO_wstr_init_static (&sf->_sbf._f, (wchar_t *)string, 0, NULL);
+  return &sf->_sbf._f;
+}
+
+#endif /* strfile.h.  */
diff --git a/libio/swscanf.c b/libio/swscanf.c
index c8686bc..90f721c 100644
--- a/libio/swscanf.c
+++ b/libio/swscanf.c
@@ -15,20 +15,22 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <libioP.h>
 #include <stdarg.h>
-#include <wchar.h>
+#include "strfile.h"
 
 /* Read formatted input from S, according to the format string FORMAT.  */
-/* VARARGS2 */
+
 int
 __swscanf (const wchar_t *s, const wchar_t *format, ...)
 {
   va_list arg;
   int done;
+  _IO_strfile sf;
+  struct _IO_wide_data wd;
+  FILE *f = _IO_strfile_readw (&sf, &wd, s);
 
   va_start (arg, format);
-  done = __vswscanf (s, format, arg);
+  done = __vfwscanf_internal (f, format, arg, 0);
   va_end (arg);
 
   return done;
diff --git a/libio/vscanf.c b/libio/vscanf.c
index 9c27122..a3e2dd4 100644
--- a/libio/vscanf.c
+++ b/libio/vscanf.c
@@ -32,6 +32,6 @@
 int
 _IO_vscanf (const char *format, va_list args)
 {
-  return _IO_vfscanf (_IO_stdin, format, args, NULL);
+  return __vfscanf_internal (_IO_stdin, format, args, 0);
 }
 ldbl_weak_alias (_IO_vscanf, vscanf)
diff --git a/libio/vwscanf.c b/libio/vwscanf.c
index 0d5f558..7af770c 100644
--- a/libio/vwscanf.c
+++ b/libio/vwscanf.c
@@ -30,6 +30,6 @@
 int
 __vwscanf (const wchar_t *format, va_list args)
 {
-  return _IO_vfwscanf (_IO_stdin, format, args, NULL);
+  return __vfwscanf_internal (_IO_stdin, format, args, 0);
 }
 ldbl_strong_alias (__vwscanf, vwscanf)
diff --git a/libio/wscanf.c b/libio/wscanf.c
index c8cdad0..fe27ff6 100644
--- a/libio/wscanf.c
+++ b/libio/wscanf.c
@@ -30,7 +30,7 @@ __wscanf (const wchar_t *format, ...)
   int done;
 
   va_start (arg, format);
-  done = _IO_vfwscanf (stdin, format, arg, NULL);
+  done = __vfwscanf_internal (stdin, format, arg, 0);
   va_end (arg);
 
   return done;