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

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

[Tulio Magno Quites Machado Filho]

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-dec.h contains all function declarations;
 - libio/bits/stdio2.h remains with the remaining contents, including
   redirections.
---
 include/bits/stdio2-dec.h |   1 +
 libio/Makefile            |   2 +-
 libio/bits/stdio2-dec.h   | 110 ++++++++++++++++++++++++++++++++++++++
 libio/bits/stdio2.h       |  62 ---------------------
 libio/stdio.h             |  18 +++++--
 5 files changed, 125 insertions(+), 68 deletions(-)
 create mode 100644 include/bits/stdio2-dec.h
 create mode 100644 libio/bits/stdio2-dec.h

diff --git a/include/bits/stdio2-dec.h b/include/bits/stdio2-dec.h
new file mode 100644
index 0000000000..4d74e4bf82
--- /dev/null
+++ b/include/bits/stdio2-dec.h
@@ -0,0 +1 @@
+#include <libio/bits/stdio2-dec.h>
diff --git a/libio/Makefile b/libio/Makefile
index 5336b7d595..19e2143d11 100644
--- a/libio/Makefile
+++ b/libio/Makefile
@@ -23,7 +23,7 @@ subdir	:= libio
 include ../Makeconfig
 
 headers	:= stdio.h \
-	   bits/stdio.h bits/stdio2.h bits/stdio-ldbl.h \
+	   bits/stdio.h bits/stdio2.h bits/stdio2-dec.h bits/stdio-ldbl.h \
 	   bits/types/FILE.h bits/types/__FILE.h bits/types/struct_FILE.h \
 	   bits/types/__fpos_t.h bits/types/__fpos64_t.h \
 	   bits/types/cookie_io_functions_t.h
diff --git a/libio/bits/stdio2-dec.h b/libio/bits/stdio2-dec.h
new file mode 100644
index 0000000000..80ab10bccf
--- /dev/null
+++ b/libio/bits/stdio2-dec.h
@@ -0,0 +1,110 @@
+/* Checking macros for stdio functions. Declarations only.
+   Copyright (C) 2004-2021 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-dec.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;
+
+#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-dec.h.  */
diff --git a/libio/bits/stdio2.h b/libio/bits/stdio2.h
index 40ff16b01b..4570f86a44 100644
--- a/libio/bits/stdio2.h
+++ b/libio/bits/stdio2.h
@@ -23,14 +23,6 @@
 # error "Never include <bits/stdio2.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));
-
 #ifdef __va_arg_pack
 __fortify_function int
 __NTH (sprintf (char *__restrict __s, const char *__restrict __fmt, ...))
@@ -54,15 +46,6 @@ __NTH (vsprintf (char *__restrict __s, const char *__restrict __fmt,
 }
 
 #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;
-
 # ifdef __va_arg_pack
 __fortify_function int
 __NTH (snprintf (char *__restrict __s, size_t __n,
@@ -89,15 +72,6 @@ __NTH (vsnprintf (char *__restrict __s, size_t __n,
 #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 __va_arg_pack
 __fortify_function int
 fprintf (FILE *__restrict __stream, const char *__restrict __fmt, ...)
@@ -136,12 +110,6 @@ vfprintf (FILE *__restrict __stream,
 }
 
 # 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)));
-
 #  ifdef __va_arg_pack
 __fortify_function int
 dprintf (int __fd, const char *__restrict __fmt, ...)
@@ -162,23 +130,6 @@ vdprintf (int __fd, const char *__restrict __fmt, __gnuc_va_list __ap)
 # 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)));
-
 #  ifdef __va_arg_pack
 __fortify_function int
 __NTH (asprintf (char **__restrict __ptr, const char *__restrict __fmt, ...))
@@ -231,7 +182,6 @@ __NTH (obstack_vprintf (struct obstack *__restrict __obstack,
 #endif
 
 #if __GLIBC_USE (DEPRECATED_GETS)
-extern char *__gets_chk (char *__str, size_t) __wur;
 extern char *__REDIRECT (__gets_warn, (char *__str), gets)
      __wur __warnattr ("please use fgets or getline instead, gets can't "
 		       "specify buffer size");
@@ -245,9 +195,6 @@ gets (char *__str)
 }
 #endif
 
-extern char *__fgets_chk (char *__restrict __s, size_t __size, int __n,
-			  FILE *__restrict __stream)
-    __wur __attr_access ((__write_only__, 1, 3));
 extern char *__REDIRECT (__fgets_alias,
 			 (char *__restrict __s, int __n,
 			  FILE *__restrict __stream), fgets)
@@ -269,9 +216,6 @@ fgets (char *__restrict __s, int __n, FILE *__restrict __stream)
   return __fgets_chk (__s, sz, __n, __stream);
 }
 
-extern size_t __fread_chk (void *__restrict __ptr, size_t __ptrlen,
-			   size_t __size, size_t __n,
-			   FILE *__restrict __stream) __wur;
 extern size_t __REDIRECT (__fread_alias,
 			  (void *__restrict __ptr, size_t __size,
 			   size_t __n, FILE *__restrict __stream),
@@ -297,9 +241,6 @@ fread (void *__restrict __ptr, size_t __size, size_t __n,
 }
 
 #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));
 extern char *__REDIRECT (__fgets_unlocked_alias,
 			 (char *__restrict __s, int __n,
 			  FILE *__restrict __stream), fgets_unlocked)
@@ -324,9 +265,6 @@ fgets_unlocked (char *__restrict __s, int __n, FILE *__restrict __stream)
 
 #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;
 extern size_t __REDIRECT (__fread_unlocked_alias,
 			  (void *__restrict __ptr, size_t __size,
 			   size_t __n, FILE *__restrict __stream),
diff --git a/libio/stdio.h b/libio/stdio.h
index f208f5ef79..da763c9f1b 100644
--- a/libio/stdio.h
+++ b/libio/stdio.h
@@ -885,20 +885,28 @@ extern void funlockfile (FILE *__stream) __THROW;
 extern int __uflow (FILE *);
 extern int __overflow (FILE *, int);
 
+#if __USE_FORTIFY_LEVEL > 0 && defined __fortify_function
+/* Declare all functions from bits/stdio2-dec.h first.  */
+# include <bits/stdio2-dec.h>
+#endif
+
+/* The following headers provide asm redirections.  These redirections must
+   appear before the first usage of these functions, e.g. in bits/stdio.h.  */
+#include <bits/floatn.h>
+#if defined __LDBL_COMPAT || __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 1
+# include <bits/stdio-ldbl.h>
+#endif
+
 /* If we are compiling with optimizing read this file.  It contains
    several optimizing inline functions and macros.  */
 #ifdef __USE_EXTERN_INLINES
 # include <bits/stdio.h>
 #endif
 #if __USE_FORTIFY_LEVEL > 0 && defined __fortify_function
+/* Now include the function definitions and redirects too.  */
 # include <bits/stdio2.h>
 #endif
 
-#include <bits/floatn.h>
-#if defined __LDBL_COMPAT || __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 1
-# include <bits/stdio-ldbl.h>
-#endif
-
 __END_DECLS
 
 #endif /* <stdio.h> included.  */
-- 
2.33.1

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

[Paul E Murphy]

On 12/15/21 1:23 PM, Tulio Magno Quites Machado Filho via Libc-alpha wrote:
> 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-dec.h contains all function declarations;
>   - libio/bits/stdio2.h remains with the remaining contents, including
>     redirections.
> ---
>   include/bits/stdio2-dec.h |   1 +
>   libio/Makefile            |   2 +-
>   libio/bits/stdio2-dec.h   | 110 ++++++++++++++++++++++++++++++++++++++
>   libio/bits/stdio2.h       |  62 ---------------------
>   libio/stdio.h             |  18 +++++--
>   5 files changed, 125 insertions(+), 68 deletions(-)
>   create mode 100644 include/bits/stdio2-dec.h
>   create mode 100644 libio/bits/stdio2-dec.h
> 
> diff --git a/include/bits/stdio2-dec.h b/include/bits/stdio2-dec.h
> new file mode 100644
> index 0000000000..4d74e4bf82
> --- /dev/null
> +++ b/include/bits/stdio2-dec.h
> @@ -0,0 +1 @@
> +#include <libio/bits/stdio2-dec.h>
> diff --git a/libio/Makefile b/libio/Makefile
> index 5336b7d595..19e2143d11 100644
> --- a/libio/Makefile
> +++ b/libio/Makefile
> @@ -23,7 +23,7 @@ subdir	:= libio
>   include ../Makeconfig
> 
>   headers	:= stdio.h \
> -	   bits/stdio.h bits/stdio2.h bits/stdio-ldbl.h \
> +	   bits/stdio.h bits/stdio2.h bits/stdio2-dec.h bits/stdio-ldbl.h \
>   	   bits/types/FILE.h bits/types/__FILE.h bits/types/struct_FILE.h \
>   	   bits/types/__fpos_t.h bits/types/__fpos64_t.h \
>   	   bits/types/cookie_io_functions_t.h
> diff --git a/libio/bits/stdio2-dec.h b/libio/bits/stdio2-dec.h
> new file mode 100644
> index 0000000000..80ab10bccf
> --- /dev/null
> +++ b/libio/bits/stdio2-dec.h
> @@ -0,0 +1,110 @@
> +/* Checking macros for stdio functions. Declarations only.
> +   Copyright (C) 2004-2021 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-dec.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));OK.

> +
> +#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;
> +
> +#endif
> +
OK.


> +#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
OK.

> +
> +#if __GLIBC_USE (DEPRECATED_GETS)
> +extern char *__gets_chk (char *__str, size_t) __wur;
> +#endif
OK.

> +
> +extern char *__fgets_chk (char *__restrict __s, size_t __size, int __n,
> +			  FILE *__restrict __stream)
> +    __wur __attr_access ((__write_only__, 1, 3));
> +
OK.

> +extern size_t __fread_chk (void *__restrict __ptr, size_t __ptrlen,
> +			   size_t __size, size_t __n,
> +			   FILE *__restrict __stream) __wur;
> +
OK.

> +#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
OK.

> +
> +#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-dec.h.  */
OK.


> diff --git a/libio/bits/stdio2.h b/libio/bits/stdio2.h
> index 40ff16b01b..4570f86a44 100644
> --- a/libio/bits/stdio2.h
> +++ b/libio/bits/stdio2.h
> @@ -23,14 +23,6 @@
>   # error "Never include <bits/stdio2.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));
> -

OK.


>   #ifdef __va_arg_pack
>   __fortify_function int
>   __NTH (sprintf (char *__restrict __s, const char *__restrict __fmt, ...))
> @@ -54,15 +46,6 @@ __NTH (vsprintf (char *__restrict __s, const char *__restrict __fmt,
>   }
> 
>   #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;
> -
OK.

>   # ifdef __va_arg_pack
>   __fortify_function int
>   __NTH (snprintf (char *__restrict __s, size_t __n,
> @@ -89,15 +72,6 @@ __NTH (vsnprintf (char *__restrict __s, size_t __n,
>   #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);
> -OK.


>   # ifdef __va_arg_pack
>   __fortify_function int
>   fprintf (FILE *__restrict __stream, const char *__restrict __fmt, ...)
> @@ -136,12 +110,6 @@ vfprintf (FILE *__restrict __stream,
>   }
> 
>   # 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)));
> -
OK.

>   #  ifdef __va_arg_pack
>   __fortify_function int
>   dprintf (int __fd, const char *__restrict __fmt, ...)
> @@ -162,23 +130,6 @@ vdprintf (int __fd, const char *__restrict __fmt, __gnuc_va_list __ap)
>   # 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)));
> -
OK.

>   #  ifdef __va_arg_pack
>   __fortify_function int
>   __NTH (asprintf (char **__restrict __ptr, const char *__restrict __fmt, ...))
> @@ -231,7 +182,6 @@ __NTH (obstack_vprintf (struct obstack *__restrict __obstack,
>   #endif
> 
>   #if __GLIBC_USE (DEPRECATED_GETS)
> -extern char *__gets_chk (char *__str, size_t) __wur;
OK.

>   extern char *__REDIRECT (__gets_warn, (char *__str), gets)
>        __wur __warnattr ("please use fgets or getline instead, gets can't "
>   		       "specify buffer size");
> @@ -245,9 +195,6 @@ gets (char *__str)
>   }
>   #endif
> 
> -extern char *__fgets_chk (char *__restrict __s, size_t __size, int __n,
> -			  FILE *__restrict __stream)
> -    __wur __attr_access ((__write_only__, 1, 3));
OK.

>   extern char *__REDIRECT (__fgets_alias,
>   			 (char *__restrict __s, int __n,
>   			  FILE *__restrict __stream), fgets)
> @@ -269,9 +216,6 @@ fgets (char *__restrict __s, int __n, FILE *__restrict __stream)
>     return __fgets_chk (__s, sz, __n, __stream);
>   }
> 
> -extern size_t __fread_chk (void *__restrict __ptr, size_t __ptrlen,
> -			   size_t __size, size_t __n,
> -			   FILE *__restrict __stream) __wur;
OK.

>   extern size_t __REDIRECT (__fread_alias,
>   			  (void *__restrict __ptr, size_t __size,
>   			   size_t __n, FILE *__restrict __stream),
> @@ -297,9 +241,6 @@ fread (void *__restrict __ptr, size_t __size, size_t __n,
>   }
> 
>   #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));
OK.

>   extern char *__REDIRECT (__fgets_unlocked_alias,
>   			 (char *__restrict __s, int __n,
>   			  FILE *__restrict __stream), fgets_unlocked)
> @@ -324,9 +265,6 @@ fgets_unlocked (char *__restrict __s, int __n, FILE *__restrict __stream)
> 
>   #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;
OK.

>   extern size_t __REDIRECT (__fread_unlocked_alias,
>   			  (void *__restrict __ptr, size_t __size,
>   			   size_t __n, FILE *__restrict __stream),
> diff --git a/libio/stdio.h b/libio/stdio.h
> index f208f5ef79..da763c9f1b 100644
> --- a/libio/stdio.h
> +++ b/libio/stdio.h
> @@ -885,20 +885,28 @@ extern void funlockfile (FILE *__stream) __THROW;
>   extern int __uflow (FILE *);
>   extern int __overflow (FILE *, int);
> 
> +#if __USE_FORTIFY_LEVEL > 0 && defined __fortify_function
> +/* Declare all functions from bits/stdio2-dec.h first.  */
> +# include <bits/stdio2-dec.h>
> +#endif
> +
> +/* The following headers provide asm redirections.  These redirections must
> +   appear before the first usage of these functions, e.g. in bits/stdio.h.  */
> +#include <bits/floatn.h>
OK. I think you are just moving the existing code, but is this include 
redundant? It seems to happen a bit earlier around line 430.

> +#if defined __LDBL_COMPAT || __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 1
> +# include <bits/stdio-ldbl.h>
> +#endif
> +
>   /* If we are compiling with optimizing read this file.  It contains
>      several optimizing inline functions and macros.  */
>   #ifdef __USE_EXTERN_INLINES
>   # include <bits/stdio.h>
>   #endif
>   #if __USE_FORTIFY_LEVEL > 0 && defined __fortify_function
> +/* Now include the function definitions and redirects too.  */
>   # include <bits/stdio2.h>
>   #endif
> 
> -#include <bits/floatn.h>
> -#if defined __LDBL_COMPAT || __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 1
> -# include <bits/stdio-ldbl.h>
> -#endif
> -
OK.

>   __END_DECLS
> 
>   #endif /* <stdio.h> included.  */
>

One minor question about the new file name, is "dec" meant to read as 
"declaration"?

This LGTM provided it passes build-many-glibc.py.

[PATCHv2] Apply asm redirections in stdio.h before first use [BZ #27087]

[Tulio Magno Quites Machado Filho]

Changes since v1:
 - Removed the duplicated inclusion of bits/floatn.h.

I plan to backport this fix to at least glibc 2.35.

--- 8< ---

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

Tested with build-many-glibcs.py.
---
 include/bits/stdio2-dec.h |   1 +
 libio/Makefile            |   2 +-
 libio/bits/stdio2-dec.h   | 110 ++++++++++++++++++++++++++++++++++++++
 libio/bits/stdio2.h       |  62 ---------------------
 libio/stdio.h             |  17 ++++--
 5 files changed, 124 insertions(+), 68 deletions(-)
 create mode 100644 include/bits/stdio2-dec.h
 create mode 100644 libio/bits/stdio2-dec.h

diff --git a/include/bits/stdio2-dec.h b/include/bits/stdio2-dec.h
new file mode 100644
index 0000000000..4d74e4bf82
--- /dev/null
+++ b/include/bits/stdio2-dec.h
@@ -0,0 +1 @@
+#include <libio/bits/stdio2-dec.h>
diff --git a/libio/Makefile b/libio/Makefile
index e97387743f..13ca515fd9 100644
--- a/libio/Makefile
+++ b/libio/Makefile
@@ -23,7 +23,7 @@ subdir	:= libio
 include ../Makeconfig
 
 headers	:= stdio.h \
-	   bits/stdio.h bits/stdio2.h bits/stdio-ldbl.h \
+	   bits/stdio.h bits/stdio2.h bits/stdio2-dec.h bits/stdio-ldbl.h \
 	   bits/types/FILE.h bits/types/__FILE.h bits/types/struct_FILE.h \
 	   bits/types/__fpos_t.h bits/types/__fpos64_t.h \
 	   bits/types/cookie_io_functions_t.h
diff --git a/libio/bits/stdio2-dec.h b/libio/bits/stdio2-dec.h
new file mode 100644
index 0000000000..80ab10bccf
--- /dev/null
+++ b/libio/bits/stdio2-dec.h
@@ -0,0 +1,110 @@
+/* Checking macros for stdio functions. Declarations only.
+   Copyright (C) 2004-2021 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-dec.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;
+
+#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-dec.h.  */
diff --git a/libio/bits/stdio2.h b/libio/bits/stdio2.h
index b0b655ee7a..b1e200e716 100644
--- a/libio/bits/stdio2.h
+++ b/libio/bits/stdio2.h
@@ -23,14 +23,6 @@
 # error "Never include <bits/stdio2.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));
-
 #ifdef __va_arg_pack
 __fortify_function int
 __NTH (sprintf (char *__restrict __s, const char *__restrict __fmt, ...))
@@ -54,15 +46,6 @@ __NTH (vsprintf (char *__restrict __s, const char *__restrict __fmt,
 }
 
 #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;
-
 # ifdef __va_arg_pack
 __fortify_function int
 __NTH (snprintf (char *__restrict __s, size_t __n,
@@ -89,15 +72,6 @@ __NTH (vsnprintf (char *__restrict __s, size_t __n,
 #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 __va_arg_pack
 __fortify_function int
 fprintf (FILE *__restrict __stream, const char *__restrict __fmt, ...)
@@ -136,12 +110,6 @@ vfprintf (FILE *__restrict __stream,
 }
 
 # 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)));
-
 #  ifdef __va_arg_pack
 __fortify_function int
 dprintf (int __fd, const char *__restrict __fmt, ...)
@@ -162,23 +130,6 @@ vdprintf (int __fd, const char *__restrict __fmt, __gnuc_va_list __ap)
 # 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)));
-
 #  ifdef __va_arg_pack
 __fortify_function int
 __NTH (asprintf (char **__restrict __ptr, const char *__restrict __fmt, ...))
@@ -231,7 +182,6 @@ __NTH (obstack_vprintf (struct obstack *__restrict __obstack,
 #endif
 
 #if __GLIBC_USE (DEPRECATED_GETS)
-extern char *__gets_chk (char *__str, size_t) __wur;
 extern char *__REDIRECT (__gets_warn, (char *__str), gets)
      __wur __warnattr ("please use fgets or getline instead, gets can't "
 		       "specify buffer size");
@@ -245,9 +195,6 @@ gets (char *__str)
 }
 #endif
 
-extern char *__fgets_chk (char *__restrict __s, size_t __size, int __n,
-			  FILE *__restrict __stream)
-    __wur __attr_access ((__write_only__, 1, 3));
 extern char *__REDIRECT (__fgets_alias,
 			 (char *__restrict __s, int __n,
 			  FILE *__restrict __stream), fgets)
@@ -269,9 +216,6 @@ fgets (char *__restrict __s, int __n, FILE *__restrict __stream)
   return __fgets_chk (__s, sz, __n, __stream);
 }
 
-extern size_t __fread_chk (void *__restrict __ptr, size_t __ptrlen,
-			   size_t __size, size_t __n,
-			   FILE *__restrict __stream) __wur;
 extern size_t __REDIRECT (__fread_alias,
 			  (void *__restrict __ptr, size_t __size,
 			   size_t __n, FILE *__restrict __stream),
@@ -297,9 +241,6 @@ fread (void *__restrict __ptr, size_t __size, size_t __n,
 }
 
 #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));
 extern char *__REDIRECT (__fgets_unlocked_alias,
 			 (char *__restrict __s, int __n,
 			  FILE *__restrict __stream), fgets_unlocked)
@@ -324,9 +265,6 @@ fgets_unlocked (char *__restrict __s, int __n, FILE *__restrict __stream)
 
 #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;
 extern size_t __REDIRECT (__fread_unlocked_alias,
 			  (void *__restrict __ptr, size_t __size,
 			   size_t __n, FILE *__restrict __stream),
diff --git a/libio/stdio.h b/libio/stdio.h
index e6425341ce..f2b9a10d24 100644
--- a/libio/stdio.h
+++ b/libio/stdio.h
@@ -885,20 +885,27 @@ extern void funlockfile (FILE *__stream) __THROW;
 extern int __uflow (FILE *);
 extern int __overflow (FILE *, int);
 
+#if __USE_FORTIFY_LEVEL > 0 && defined __fortify_function
+/* Declare all functions from bits/stdio2-dec.h first.  */
+# include <bits/stdio2-dec.h>
+#endif
+
+/* The following headers provide asm redirections.  These redirections must
+   appear before the first usage of these functions, e.g. in bits/stdio.h.  */
+#if defined __LDBL_COMPAT || __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 1
+# include <bits/stdio-ldbl.h>
+#endif
+
 /* If we are compiling with optimizing read this file.  It contains
    several optimizing inline functions and macros.  */
 #ifdef __USE_EXTERN_INLINES
 # include <bits/stdio.h>
 #endif
 #if __USE_FORTIFY_LEVEL > 0 && defined __fortify_function
+/* Now include the function definitions and redirects too.  */
 # include <bits/stdio2.h>
 #endif
 
-#include <bits/floatn.h>
-#if defined __LDBL_COMPAT || __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 1
-# include <bits/stdio-ldbl.h>
-#endif
-
 __END_DECLS
 
 #endif /* <stdio.h> included.  */
-- 
2.35.3

Re: [PATCHv2] Apply asm redirections in stdio.h before first use [BZ #27087]

[Florian Weimer]

* Tulio Magno Quites Machado Filho:

> diff --git a/libio/bits/stdio2-dec.h b/libio/bits/stdio2-dec.h
> new file mode 100644
> index 0000000000..80ab10bccf
> --- /dev/null
> +++ b/libio/bits/stdio2-dec.h
> @@ -0,0 +1,110 @@
> +/* Checking macros for stdio functions. Declarations only.
> +   Copyright (C) 2004-2021 Free Software Foundation, Inc.

Copyright range should end in 2022.

> +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 is missing for __vsnprintf_chk?  Hmm, I see that it was
missing before as well.

Thanks,
Florian

Re: [PATCHv2] Apply asm redirections in stdio.h before first use [BZ #27087]

[Andreas Schwab]

On Jun 30 2022, Tulio Magno Quites Machado Filho via Libc-alpha wrote:

>  - libio/bits/stdio2-dec.h contains all function declarations;

The usual abbreviation for `declaration' is `decl', whereas `dec' is
more often understood as `decimal'.

-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."

[PATCHv3] Apply asm redirections in stdio.h before first use [BZ #27087]

[Tulio Magno Quites Machado Filho]

Changes since v2:
 - Fixed copyright years.
 - Added access attribute to __vsnprintf_chk.
 - Renamed headers stdio2-dec.h to stdio2-decl.h.

Changes since v1:
 - Removed the duplicated inclusion of bits/floatn.h.

I plan to backport this fix to at least glibc 2.35.

--- 8< ---

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.
---
 include/bits/stdio2-decl.h |   1 +
 libio/Makefile             |   2 +-
 libio/bits/stdio2-decl.h   | 111 +++++++++++++++++++++++++++++++++++++
 libio/bits/stdio2.h        |  62 ---------------------
 libio/stdio.h              |  17 ++++--
 5 files changed, 125 insertions(+), 68 deletions(-)
 create mode 100644 include/bits/stdio2-decl.h
 create mode 100644 libio/bits/stdio2-decl.h

diff --git a/include/bits/stdio2-decl.h b/include/bits/stdio2-decl.h
new file mode 100644
index 0000000000..bbb052f192
--- /dev/null
+++ b/include/bits/stdio2-decl.h
@@ -0,0 +1 @@
+#include <libio/bits/stdio2-decl.h>
diff --git a/libio/Makefile b/libio/Makefile
index e97387743f..3a02611020 100644
--- a/libio/Makefile
+++ b/libio/Makefile
@@ -23,7 +23,7 @@ subdir	:= libio
 include ../Makeconfig
 
 headers	:= stdio.h \
-	   bits/stdio.h bits/stdio2.h bits/stdio-ldbl.h \
+	   bits/stdio.h bits/stdio2.h bits/stdio2-decl.h bits/stdio-ldbl.h \
 	   bits/types/FILE.h bits/types/__FILE.h bits/types/struct_FILE.h \
 	   bits/types/__fpos_t.h bits/types/__fpos64_t.h \
 	   bits/types/cookie_io_functions_t.h
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.  */
diff --git a/libio/bits/stdio2.h b/libio/bits/stdio2.h
index b0b655ee7a..b1e200e716 100644
--- a/libio/bits/stdio2.h
+++ b/libio/bits/stdio2.h
@@ -23,14 +23,6 @@
 # error "Never include <bits/stdio2.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));
-
 #ifdef __va_arg_pack
 __fortify_function int
 __NTH (sprintf (char *__restrict __s, const char *__restrict __fmt, ...))
@@ -54,15 +46,6 @@ __NTH (vsprintf (char *__restrict __s, const char *__restrict __fmt,
 }
 
 #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;
-
 # ifdef __va_arg_pack
 __fortify_function int
 __NTH (snprintf (char *__restrict __s, size_t __n,
@@ -89,15 +72,6 @@ __NTH (vsnprintf (char *__restrict __s, size_t __n,
 #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 __va_arg_pack
 __fortify_function int
 fprintf (FILE *__restrict __stream, const char *__restrict __fmt, ...)
@@ -136,12 +110,6 @@ vfprintf (FILE *__restrict __stream,
 }
 
 # 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)));
-
 #  ifdef __va_arg_pack
 __fortify_function int
 dprintf (int __fd, const char *__restrict __fmt, ...)
@@ -162,23 +130,6 @@ vdprintf (int __fd, const char *__restrict __fmt, __gnuc_va_list __ap)
 # 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)));
-
 #  ifdef __va_arg_pack
 __fortify_function int
 __NTH (asprintf (char **__restrict __ptr, const char *__restrict __fmt, ...))
@@ -231,7 +182,6 @@ __NTH (obstack_vprintf (struct obstack *__restrict __obstack,
 #endif
 
 #if __GLIBC_USE (DEPRECATED_GETS)
-extern char *__gets_chk (char *__str, size_t) __wur;
 extern char *__REDIRECT (__gets_warn, (char *__str), gets)
      __wur __warnattr ("please use fgets or getline instead, gets can't "
 		       "specify buffer size");
@@ -245,9 +195,6 @@ gets (char *__str)
 }
 #endif
 
-extern char *__fgets_chk (char *__restrict __s, size_t __size, int __n,
-			  FILE *__restrict __stream)
-    __wur __attr_access ((__write_only__, 1, 3));
 extern char *__REDIRECT (__fgets_alias,
 			 (char *__restrict __s, int __n,
 			  FILE *__restrict __stream), fgets)
@@ -269,9 +216,6 @@ fgets (char *__restrict __s, int __n, FILE *__restrict __stream)
   return __fgets_chk (__s, sz, __n, __stream);
 }
 
-extern size_t __fread_chk (void *__restrict __ptr, size_t __ptrlen,
-			   size_t __size, size_t __n,
-			   FILE *__restrict __stream) __wur;
 extern size_t __REDIRECT (__fread_alias,
 			  (void *__restrict __ptr, size_t __size,
 			   size_t __n, FILE *__restrict __stream),
@@ -297,9 +241,6 @@ fread (void *__restrict __ptr, size_t __size, size_t __n,
 }
 
 #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));
 extern char *__REDIRECT (__fgets_unlocked_alias,
 			 (char *__restrict __s, int __n,
 			  FILE *__restrict __stream), fgets_unlocked)
@@ -324,9 +265,6 @@ fgets_unlocked (char *__restrict __s, int __n, FILE *__restrict __stream)
 
 #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;
 extern size_t __REDIRECT (__fread_unlocked_alias,
 			  (void *__restrict __ptr, size_t __size,
 			   size_t __n, FILE *__restrict __stream),
diff --git a/libio/stdio.h b/libio/stdio.h
index e6425341ce..0e0f16b464 100644
--- a/libio/stdio.h
+++ b/libio/stdio.h
@@ -885,20 +885,27 @@ extern void funlockfile (FILE *__stream) __THROW;
 extern int __uflow (FILE *);
 extern int __overflow (FILE *, int);
 
+#if __USE_FORTIFY_LEVEL > 0 && defined __fortify_function
+/* Declare all functions from bits/stdio2-decl.h first.  */
+# include <bits/stdio2-decl.h>
+#endif
+
+/* The following headers provide asm redirections.  These redirections must
+   appear before the first usage of these functions, e.g. in bits/stdio.h.  */
+#if defined __LDBL_COMPAT || __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 1
+# include <bits/stdio-ldbl.h>
+#endif
+
 /* If we are compiling with optimizing read this file.  It contains
    several optimizing inline functions and macros.  */
 #ifdef __USE_EXTERN_INLINES
 # include <bits/stdio.h>
 #endif
 #if __USE_FORTIFY_LEVEL > 0 && defined __fortify_function
+/* Now include the function definitions and redirects too.  */
 # include <bits/stdio2.h>
 #endif
 
-#include <bits/floatn.h>
-#if defined __LDBL_COMPAT || __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 1
-# include <bits/stdio-ldbl.h>
-#endif
-
 __END_DECLS
 
 #endif /* <stdio.h> included.  */
-- 
2.35.3

Re: [PATCHv3] Apply asm redirections in stdio.h before first use [BZ #27087]

[Paul E Murphy]

On 7/7/22 4:12 PM, Tulio Magno Quites Machado Filho wrote:
> Changes since v2:
>   - Fixed copyright years.
>   - Added access attribute to __vsnprintf_chk.
>   - Renamed headers stdio2-dec.h to stdio2-decl.h.
> 
> Changes since v1:
>   - Removed the duplicated inclusion of bits/floatn.h.
> 
> I plan to backport this fix to at least glibc 2.35.
> 
> --- 8< ---
> 
> 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.

Thanks. LGTM.

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

Re: [PATCHv3] Apply asm redirections in stdio.h before first use [BZ #27087]

[Carlos O'Donell]

On 7/11/22 16:33, Paul E Murphy via Libc-alpha wrote:
> 
> 
> On 7/7/22 4:12 PM, Tulio Magno Quites Machado Filho wrote:
>> Changes since v2:
>>   - Fixed copyright years.
>>   - Added access attribute to __vsnprintf_chk.
>>   - Renamed headers stdio2-dec.h to stdio2-decl.h.
>>
>> Changes since v1:
>>   - Removed the duplicated inclusion of bits/floatn.h.
>>
>> I plan to backport this fix to at least glibc 2.35.
>>
>> --- 8< ---
>>
>> 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.
> 
> Thanks. LGTM.
> 
> Reviewed-by: Paul E. Murphy <murphyp@linux.ibm.com>
> 

This patch was tested in Fedora by our downstream users:
https://bugzilla.redhat.com/show_bug.cgi?id=2100546#c24

This LGTM as RM for glibc 2.36.

-- 
Cheers,
Carlos.

Re: [PATCHv3] Apply asm redirections in stdio.h before first use [BZ #27087]

[Tulio Magno Quites Machado Filho]

Carlos O'Donell via Libc-alpha <libc-alpha@sourceware.org> writes:

> On 7/11/22 16:33, Paul E Murphy via Libc-alpha wrote:

>> Thanks. LGTM.
>> 
>> Reviewed-by: Paul E. Murphy <murphyp@linux.ibm.com>
>> 
>
> This patch was tested in Fedora by our downstream users:
> https://bugzilla.redhat.com/show_bug.cgi?id=2100546#c24
>
> This LGTM as RM for glibc 2.36.

Pushed as d0fa09a7701956036ff36f8ca188e9fff81553d8.

Thanks!

-- 
Tulio Magno