fortify-headers

standalone fortify-source implementation
git clone git://git.2f30.org/fortify-headers.git
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commit a9ffac8596b094da8563aa5dd5d81c946670afe5
parent 6e7e43ff992fa232b186cec9fc2920ca260c27a6
Author: A. Wilcox <AWilcox@Wilcox-Tech.com>
Date:   Sat, 23 Jun 2018 17:57:48 -0500

Don't use __extension__ in C++ code

A few important notes:

*  __extension__ is a GNU C "alternate" keyword, not a C++ keyword.[1]

*  __extension__ is designed to work on "expressions"; it does work on
   #include_next in C mode, but it has no effect in C++ mode; the
   warning will still appear, if enabled, even with __extension__
   preceding #include_next.  This is because #include_next is not
   considered an expression in C++, so the compiler attaches
   __extension__ to the first expression of the header.

All of this leads us to a build failure while building at least all
Mozilla software.  Moz has an alternate -isystem dir searched before
/usr/include that overrides some headers, including <features.h>.  The
first statement in each of these headers is a #pragma, and since
__extension__ is looking for an expression, and #pragma is a "null"
expression, we end up with the following error:

dist/system_wrappers/features.h:1:9: error: '#pragma' is not allowed here

Since __extension__ has no effect on #include_next in C++ mode anyway,
and since it can cause breakage, this commit omits __extension__ in C++
mode.

[1]: https://gcc.gnu.org/onlinedocs/gcc-6.4.0/gcc/Alternate-Keywords.html

Diffstat:
include/poll.h | 2++
include/stdio.h | 2++
include/stdlib.h | 4++++
include/string.h | 2++
include/sys/select.h | 2++
include/sys/socket.h | 2++
include/unistd.h | 2++
include/wchar.h | 8++++++++
8 files changed, 24 insertions(+), 0 deletions(-)

diff --git a/include/poll.h b/include/poll.h @@ -16,7 +16,9 @@ #ifndef _FORTIFY_POLL_H #define _FORTIFY_POLL_H +#ifndef __cplusplus __extension__ +#endif #include_next <poll.h> #if defined(_FORTIFY_SOURCE) && _FORTIFY_SOURCE > 0 && defined(__OPTIMIZE__) && __OPTIMIZE__ > 0 diff --git a/include/stdio.h b/include/stdio.h @@ -16,7 +16,9 @@ #ifndef _FORTIFY_STDIO_H #define _FORTIFY_STDIO_H +#ifndef __cplusplus __extension__ +#endif #include_next <stdio.h> #if defined(_FORTIFY_SOURCE) && _FORTIFY_SOURCE > 0 && defined(__OPTIMIZE__) && __OPTIMIZE__ > 0 diff --git a/include/stdlib.h b/include/stdlib.h @@ -16,12 +16,16 @@ #ifndef _FORTIFY_STDLIB_H #define _FORTIFY_STDLIB_H +#ifndef __cplusplus __extension__ +#endif #include_next <stdlib.h> #if defined(_FORTIFY_SOURCE) && _FORTIFY_SOURCE > 0 && defined(__OPTIMIZE__) && __OPTIMIZE__ > 0 #if defined(_XOPEN_SOURCE) || defined(_GNU_SOURCE) || defined(_BSD_SOURCE) +#ifndef __cplusplus __extension__ +#endif #include_next <limits.h> #endif diff --git a/include/string.h b/include/string.h @@ -16,7 +16,9 @@ #ifndef _FORTIFY_STRING_H #define _FORTIFY_STRING_H +#ifndef __cplusplus __extension__ +#endif #include_next <string.h> #if defined(_FORTIFY_SOURCE) && _FORTIFY_SOURCE > 0 && defined(__OPTIMIZE__) && __OPTIMIZE__ > 0 diff --git a/include/sys/select.h b/include/sys/select.h @@ -16,7 +16,9 @@ #ifndef _FORTIFY_SYS_SELECT_H #define _FORTIFY_SYS_SELECT_H +#ifndef __cplusplus __extension__ +#endif #include_next <sys/select.h> #if defined(_FORTIFY_SOURCE) && _FORTIFY_SOURCE > 0 && defined(__OPTIMIZE__) && __OPTIMIZE__ > 0 diff --git a/include/sys/socket.h b/include/sys/socket.h @@ -16,7 +16,9 @@ #ifndef _FORTIFY_SYS_SOCKET_H #define _FORTIFY_SYS_SOCKET_H +#ifndef __cplusplus __extension__ +#endif #include_next <sys/socket.h> #if defined(_FORTIFY_SOURCE) && _FORTIFY_SOURCE > 0 && defined(__OPTIMIZE__) && __OPTIMIZE__ > 0 diff --git a/include/unistd.h b/include/unistd.h @@ -16,7 +16,9 @@ #ifndef _FORTIFY_UNISTD_H #define _FORTIFY_UNISTD_H +#ifndef __cplusplus __extension__ +#endif #include_next <unistd.h> #if defined(_FORTIFY_SOURCE) && _FORTIFY_SOURCE > 0 && defined(__OPTIMIZE__) && __OPTIMIZE__ > 0 diff --git a/include/wchar.h b/include/wchar.h @@ -16,13 +16,21 @@ #ifndef _FORTIFY_WCHAR_H #define _FORTIFY_WCHAR_H +#ifndef __cplusplus __extension__ +#endif #include_next <limits.h> +#ifndef __cplusplus __extension__ +#endif #include_next <stdlib.h> +#ifndef __cplusplus __extension__ +#endif #include_next <string.h> +#ifndef __cplusplus __extension__ +#endif #include_next <wchar.h> #if defined(_FORTIFY_SOURCE) && _FORTIFY_SOURCE > 0 && defined(__OPTIMIZE__) && __OPTIMIZE__ > 0