From 2b8a944a7d9d5dcaafbabf3d0dbf57dab36f926a Mon Sep 17 00:00:00 2001
From: Chris Johns <chrisj@rtems.org>
Date: Wed, 12 Apr 2023 14:26:00 -1000
Subject: [PATCH] rtems: Add legacy network support and fix LDFLAGS

RTEMS 6 has moved the legacy network support out of the main repo
to a 3rd party library. This change adds support for using the
legacy networking stack with EPICS in a backwards compatible way.

A BSP can be built with libbsd or the legacy stack and by default
EPICS 7 assumes libbsd.

This patch also fixes the LDFLAGS adding the RTEMS LDFLAGS imported
from Makefile.inc.
---
 configure/os/CONFIG.Common.RTEMS | 48 ++++++++++++++++++++++++++------
 configure/toolchain.c            | 22 +++++++++++++--
 2 files changed, 59 insertions(+), 11 deletions(-)

diff --git a/configure/os/CONFIG.Common.RTEMS b/configure/os/CONFIG.Common.RTEMS
index a736addaa..c58ac7bdc 100644
--- a/configure/os/CONFIG.Common.RTEMS
+++ b/configure/os/CONFIG.Common.RTEMS
@@ -65,7 +65,7 @@ CXXFLAGS = $($(BUILD_CLASS)_CXXFLAGS) $(POSIX_CXXFLAGS) $(OPT_CXXFLAGS)\
  $(USR_CXXFLAGS) $(CMD_CXXFLAGS) $(ARCH_DEP_CXXFLAGS) $(CODE_CXXFLAGS)\
  $(STATIC_CXXFLAGS) $(OP_SYS_CXXFLAGS) $(LIBRARY_SRC_CFLAGS)
 
-LDFLAGS = $(OPT_LDFLAGS) $(TARGET_LDFLAGS) $(USR_LDFLAGS) $(CMD_LDFLAGS)\
+LDFLAGS += $(OPT_LDFLAGS) $(TARGET_LDFLAGS) $(USR_LDFLAGS) $(CMD_LDFLAGS)\
  $(POSIX_LDFLAGS) $(ARCH_DEP_LDFLAGS) $(DEBUG_LDFLAGS) $(OP_SYS_LDFLAGS)\
  $($(BUILD_CLASS)_LDFLAGS) $(RUNTIME_LDFLAGS) $(CODE_LDFLAGS)
 
@@ -102,15 +102,47 @@ OS_CLASS = RTEMS
 # Operating system compile & link flags
 OP_SYS_CFLAGS += -D__LINUX_ERRNO_EXTENSIONS__
 
-OP_SYS_CFLAGS_NET_yes = -DRTEMS_LEGACY_STACK
-OP_SYS_CFLAGS += $(OP_SYS_CFLAGS_NET_$(RTEMS_HAS_NETWORKING))
-
-ifeq ($(RTEMS_HAS_POSIX_API),yes)
-POSIX_CPPFLAGS = -D_GNU_SOURCE -D_DEFAULT_SOURCE
+# Has RTEMS been built with the internal legacy stack?
+ifeq ($(RTEMS_LEGACY_NETWORKING_INTERNAL),yes)
+RTEMS_HAS_NETWORKING = yes
+RTEMS_NETWORKING = legacy_internal
 endif
 
-OP_SYS_LDLIBS_posix_NET_yes = -ltftpfs -lnfs -lz -ltelnetd
-OP_SYS_LDLIBS_posix_NET_no = -ltftpfs -lbsd -lz
+# Has RTEMS been built with the legacy stack as a separate package?
+ifeq ($(RTEMS_LEGACY_NETWORKING),yes)
+RTEMS_HAS_NETWORKING = yes
+RTEMS_NETWORKING = legacy
+endif
+
+# Has RTEMS been built with the libbsd stack as a separate package?
+ifeq ($(RTEMS_BSD_NETWORKING),yes)
+RTEMS_HAS_NETWORKING = yes
+RTEMS_NETWORKING = bsd
+endif
+
+RTEMS_LEGACY_NET_LIB_no=
+
+# Legacy network with RTEMS 5 and earlier
+RTEMS_NET_LIB_legacy_internal=-lnfs
+OP_SYS_CFLAGS_NET_legacy_internal = -DRTEMS_LEGACY_STACK
+
+# Legacy network with RTEMS 6 is a separate package and library
+RTEMS_NET_LIB_legacy=-lnfs -lnetworking -lnfs
+OP_SYS_CFLAGS_NET_legacy = -DRTEMS_LEGACY_STACK
+
+# LibBSD network with RTEMS 5 and 6 is a separate package and library
+RTEMS_NET_LIB_bsd=-lbsd
+OP_SYS_CFLAGS_NET_bsd = -DRTEMS_LIBBSD_STACK
+
+# Set the networking flags
+OP_SYS_CFLAGS += $(OP_SYS_CFLAGS_NET_$(RTEMS_NETWORKING))
+
+POSIX_CPPFLAGS_posix = -D_GNU_SOURCE -D_DEFAULT_SOURCE
+POSIX_CPPFLAGS = $(POSIX_CPPFLAGS_$(OS_API))
+
+OP_SYS_LDLIBS_posix_NET_yes = -ltftpfs -lz -ltelnetd
+OP_SYS_LDLIBS_posix_NET_yes += $(RTEMS_NET_LIB_$(RTEMS_NETWORKING))
+OP_SYS_LDLIBS_posix_NET_no = -ltftpfs -lz
 OP_SYS_LDLIBS_score_NET_yes = -lnfs
 OP_SYS_LDLIBS_score_NET_no = -lnfs
 OP_SYS_LDLIBS += -lrtemsCom -lCom
diff --git a/configure/toolchain.c b/configure/toolchain.c
index 79333198c..af03f5246 100644
--- a/configure/toolchain.c
+++ b/configure/toolchain.c
@@ -30,9 +30,26 @@ MSVC_VER = _MSC_VER
 #ifdef __rtems__
 #include <rtems/score/cpuopts.h>
 #  if __RTEMS_MAJOR__>=5
-OS_API = posix
+     OS_API = posix
 #  else
-OS_API = score
+     OS_API = score
+#  endif
+#  if defined(RTEMS_NETWORKING)
+     /* legacy stack circa RTEMS <= 5 and networking internal to RTEMS */
+     RTEMS_LEGACY_NETWORKING_INTERNAL = yes
+#  else
+#    if !defined(__has_include)
+       /* assume old GCC implies RTEMS < 5 with mis-configured BSP */
+#      error rebuild BSP with --enable-network
+#    elif __has_include(<machine/rtems-net-legacy.h>)
+       /* legacy stack circa RTEMS > 5 */
+       RTEMS_LEGACY_NETWORKING = yes
+#    elif __has_include(<machine/rtems-bsd-version.h>)
+       /* libbsd stack */
+       RTEMS_BSD_NETWORKING = yes
+#    else
+#      error Cannot determine RTEMS network configuration
+#    endif
 #  endif
 #endif
 
@@ -51,4 +68,3 @@ COMMANDLINE_LIBRARY ?= $(strip $(if $(wildcard $(if $(GNU_DIR),$(GNU_DIR)/includ
 #if defined(_FORTIFY_SOURCE) && _FORTIFY_SOURCE>2
 OP_SYS_CPPFLAGS += -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2
 #endif
-