From 7146958a3cc0212b2c2c35917c10adde0aa57d30 Mon Sep 17 00:00:00 2001
From: Viktor Dukhovni <ietf-dane@dukhovni.org>
Date: Tue, 27 Apr 2021 13:33:26 -0400
Subject: Tighten scope of non-POSIX visibility macros

The __BSD_VISIBLE and _DARWIN_C_SOURCE macros expose non-POSIX prototypes in
system header files.  We should scope these to just the ".c" modules that
actually need them, and avoid defining them in header files used in other C
modules.
---
 includes/Rts.h        |  6 ------
 rts/LinkerInternals.h |  5 -----
 rts/posix/Itimer.c    | 21 +++++++++++++++++++++
 rts/posix/OSThreads.c | 17 +++++++++++++----
 4 files changed, 34 insertions(+), 15 deletions(-)

diff --git a/includes/Rts.h b/includes/Rts.h
index e7fb8561f6..0f96ba2eca 100644
--- a/includes/Rts.h
+++ b/includes/Rts.h
@@ -29,12 +29,6 @@ extern "C" {
 #include <windows.h>
 #endif
 
-#if defined(ios_HOST_OS) || defined(darwin_HOST_OS)
-/* Inclusion of system headers usually requires _DARWIN_C_SOURCE on Mac OS X
- * because of some specific defines like MMAP_ANON, MMAP_ANONYMOUS. */
-#define _DARWIN_C_SOURCE 1
-#endif
-
 #if !defined(IN_STG_CODE)
 #define IN_STG_CODE 0
 #endif
diff --git a/rts/LinkerInternals.h b/rts/LinkerInternals.h
index e1da899c89..167a14202d 100644
--- a/rts/LinkerInternals.h
+++ b/rts/LinkerInternals.h
@@ -13,11 +13,6 @@
 #include "linker/M32Alloc.h"
 
 #if RTS_LINKER_USE_MMAP
-#if defined(ios_HOST_OS) || defined(darwin_HOST_OS)
-/* Inclusion of system headers usually requires _DARWIN_C_SOURCE on Mac OS X
- * because of some specific defines like MMAP_ANON, MMAP_ANONYMOUS. */
-#define _DARWIN_C_SOURCE 1
-#endif
 #include <sys/mman.h>
 #endif
 
diff --git a/rts/posix/Itimer.c b/rts/posix/Itimer.c
index 80925df703..98b23f623e 100644
--- a/rts/posix/Itimer.c
+++ b/rts/posix/Itimer.c
@@ -18,6 +18,27 @@
  */
 
 #include "PosixSource.h"
+
+/* We've defined _POSIX_SOURCE via "PosixSource.h", and yet still use
+   some non-POSIX features.  With _POSIX_SOURCE defined, visibility of
+   non-POSIX extension prototypes requires _DARWIN_C_SOURCE on Mac OS X and
+   __BSD_VISIBLE on FreeBSD and DragonflyBSD.  Otherwise, for example, code
+   using pthread_setname_np(3) and variants will not compile.  We must
+   therefore define the additional macros that expose non-POSIX APIs early,
+   before any of the relevant system headers are included via "Rts.h".
+
+   An alternative approach could be to write portable wrappers or stubs for all
+   the non-posix functions in a C-module that does not include "PosixSource.h",
+   and then use only POSIX features and the portable wrapper functions in all
+   other C-modules. */
+#include "ghcconfig.h"
+#if defined(freebsd_HOST_OS) || defined(dragonfly_HOST_OS)
+#define __BSD_VISIBLE   1
+#endif
+#if defined(darwin_HOST_OS)
+#define _DARWIN_C_SOURCE 1
+#endif
+
 #include "Rts.h"
 
 /*
diff --git a/rts/posix/OSThreads.c b/rts/posix/OSThreads.c
index b815894a9f..e039b43573 100644
--- a/rts/posix/OSThreads.c
+++ b/rts/posix/OSThreads.c
@@ -9,14 +9,23 @@
 
 #include "PosixSource.h"
 
+/* We've defined _POSIX_SOURCE via "PosixSource.h", and yet still use
+   some non-POSIX features.  With _POSIX_SOURCE defined, visibility of
+   non-POSIX extension prototypes requires _DARWIN_C_SOURCE on Mac OS X and
+   __BSD_VISIBLE on FreeBSD and DragonflyBSD.  Otherwise, for example, code
+   using pthread_setname_np(3) and variants will not compile.  We must
+   therefore define the additional macros that expose non-POSIX APIs early,
+   before any of the relevant system headers are included via "Rts.h".
+
+   An alternative approach could be to write portable wrappers or stubs for all
+   the non-posix functions in a C-module that does not include "PosixSource.h",
+   and then use only POSIX features and the portable wrapper functions in all
+   other C-modules. */
+#include "ghcconfig.h"
 #if defined(freebsd_HOST_OS) || defined(dragonfly_HOST_OS)
-/* Inclusion of system headers usually requires __BSD_VISIBLE on FreeBSD and
- * DragonflyBSD, because of some specific types, like u_char, u_int, etc. */
 #define __BSD_VISIBLE   1
 #endif
 #if defined(darwin_HOST_OS)
-/* Inclusion of system headers usually requires _DARWIN_C_SOURCE on Mac OS X
- * because of some specific types like u_char, u_int, etc. */
 #define _DARWIN_C_SOURCE 1
 #endif
 
-- 
cgit v1.2.1