Apply asm redirections in stdio.h before first use [BZ #27087]

Compilers may not be able to apply asm redirections to functions after
these functions are used for the first time, e.g. clang 13.
Fix [BZ #27087] by applying all long double-related asm redirections
before using functions in bits/stdio.h.
However, as these asm redirections depend on the declarations provided
by libio/bits/stdio2.h, this header was split in 2:

 - libio/bits/stdio2-decl.h contains all function declarations;
 - libio/bits/stdio2.h remains with the remaining contents, including
   redirections.

This also adds the access attribute to __vsnprintf_chk that was missing.

Tested with build-many-glibcs.py.

Reviewed-by: Paul E. Murphy <murphyp@linux.ibm.com>

1 files changed, 111 insertions, 0 deletions

diff --git a/libio/bits/stdio2-decl.h b/libio/bits/stdio2-decl.h
new file mode 100644
index 0000000000..e398f7182b
--- /dev/null
+++ b/libio/bits/stdio2-decl.h
@@ -0,0 +1,111 @@
+/* Checking macros for stdio functions. Declarations only.
+   Copyright (C) 2004-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _BITS_STDIO2_DEC_H
+#define _BITS_STDIO2_DEC_H 1
+
+#ifndef _STDIO_H
+# error "Never include <bits/stdio2-decl.h> directly; use <stdio.h> instead."
+#endif
+
+extern int __sprintf_chk (char *__restrict __s, int __flag, size_t __slen,
+			  const char *__restrict __format, ...) __THROW
+    __attr_access ((__write_only__, 1, 3));
+extern int __vsprintf_chk (char *__restrict __s, int __flag, size_t __slen,
+			   const char *__restrict __format,
+			   __gnuc_va_list __ap) __THROW
+    __attr_access ((__write_only__, 1, 3));
+
+#if defined __USE_ISOC99 || defined __USE_UNIX98
+
+extern int __snprintf_chk (char *__restrict __s, size_t __n, int __flag,
+			   size_t __slen, const char *__restrict __format,
+			   ...) __THROW
+    __attr_access ((__write_only__, 1, 2));
+extern int __vsnprintf_chk (char *__restrict __s, size_t __n, int __flag,
+			    size_t __slen, const char *__restrict __format,
+			    __gnuc_va_list __ap) __THROW
+    __attr_access ((__write_only__, 1, 2));
+
+#endif
+
+#if __USE_FORTIFY_LEVEL > 1
+
+extern int __fprintf_chk (FILE *__restrict __stream, int __flag,
+			  const char *__restrict __format, ...);
+extern int __printf_chk (int __flag, const char *__restrict __format, ...);
+extern int __vfprintf_chk (FILE *__restrict __stream, int __flag,
+			   const char *__restrict __format, __gnuc_va_list __ap);
+extern int __vprintf_chk (int __flag, const char *__restrict __format,
+			  __gnuc_va_list __ap);
+
+# ifdef __USE_XOPEN2K8
+extern int __dprintf_chk (int __fd, int __flag, const char *__restrict __fmt,
+			  ...) __attribute__ ((__format__ (__printf__, 3, 4)));
+extern int __vdprintf_chk (int __fd, int __flag,
+			   const char *__restrict __fmt, __gnuc_va_list __arg)
+     __attribute__ ((__format__ (__printf__, 3, 0)));
+# endif
+
+# ifdef __USE_GNU
+
+extern int __asprintf_chk (char **__restrict __ptr, int __flag,
+			   const char *__restrict __fmt, ...)
+     __THROW __attribute__ ((__format__ (__printf__, 3, 4))) __wur;
+extern int __vasprintf_chk (char **__restrict __ptr, int __flag,
+			    const char *__restrict __fmt, __gnuc_va_list __arg)
+     __THROW __attribute__ ((__format__ (__printf__, 3, 0))) __wur;
+extern int __obstack_printf_chk (struct obstack *__restrict __obstack,
+				 int __flag, const char *__restrict __format,
+				 ...)
+     __THROW __attribute__ ((__format__ (__printf__, 3, 4)));
+extern int __obstack_vprintf_chk (struct obstack *__restrict __obstack,
+				  int __flag,
+				  const char *__restrict __format,
+				  __gnuc_va_list __args)
+     __THROW __attribute__ ((__format__ (__printf__, 3, 0)));
+
+# endif
+#endif
+
+#if __GLIBC_USE (DEPRECATED_GETS)
+extern char *__gets_chk (char *__str, size_t) __wur;
+#endif
+
+extern char *__fgets_chk (char *__restrict __s, size_t __size, int __n,
+			  FILE *__restrict __stream)
+    __wur __attr_access ((__write_only__, 1, 3));
+
+extern size_t __fread_chk (void *__restrict __ptr, size_t __ptrlen,
+			   size_t __size, size_t __n,
+			   FILE *__restrict __stream) __wur;
+
+#ifdef __USE_GNU
+extern char *__fgets_unlocked_chk (char *__restrict __s, size_t __size,
+				   int __n, FILE *__restrict __stream)
+    __wur __attr_access ((__write_only__, 1, 3));
+#endif
+
+#ifdef __USE_MISC
+# undef fread_unlocked
+extern size_t __fread_unlocked_chk (void *__restrict __ptr, size_t __ptrlen,
+				    size_t __size, size_t __n,
+				    FILE *__restrict __stream) __wur;
+#endif
+
+#endif /* bits/stdio2-decl.h.  */