svn commit: trunk/busybox: scripts

[vda at busybox.net]

Author: vda
Date: 2008-06-04 04:28:24 -0700 (Wed, 04 Jun 2008)
New Revision: 22211

Log:
build system: add PIE build option



Modified:
   trunk/busybox/Config.in
   trunk/busybox/Makefile
   trunk/busybox/Makefile.flags
   trunk/busybox/scripts/Makefile.IMA
   trunk/busybox/scripts/Makefile.build


Changeset:
Modified: trunk/busybox/Config.in
===================================================================
--- trunk/busybox/Config.in	2008-06-04 10:33:33 UTC (rev 22210)
+++ trunk/busybox/Config.in	2008-06-04 11:28:24 UTC (rev 22211)
@@ -262,6 +262,14 @@
 
 	  Most people will leave this set to 'N'.
 
+config PIE
+	bool "Build BusyBox as a position independent executable"
+	default n
+	depends on !STATIC
+	help
+	  (TODO: what is it and why/when is it useful?)
+	  Most people will leave this set to 'N'.
+
 config NOMMU
 	bool "Force NOMMU build"
 	default n

Modified: trunk/busybox/Makefile
===================================================================
--- trunk/busybox/Makefile	2008-06-04 10:33:33 UTC (rev 22210)
+++ trunk/busybox/Makefile	2008-06-04 11:28:24 UTC (rev 22211)
@@ -315,6 +315,8 @@
 # Use LINUXINCLUDE when you must reference the include/ directory.
 # Needed to be compatible with the O= option
 CFLAGS		:= $(CFLAGS)
+# Added only to final link stage of busybox binary
+CFLAGS_busybox	:= $(CFLAGS_busybox)
 CPPFLAGS	:= $(CPPFLAGS)
 AFLAGS		:= $(AFLAGS)
 LDFLAGS		:= $(LDFLAGS)
@@ -580,7 +582,7 @@
       cmd_busybox__ ?= $(srctree)/scripts/trylink \
       "$@" \
       "$(CC)" \
-      "$(CFLAGS)" \
+      "$(CFLAGS) $(CFLAGS_busybox)" \
       "$(LDFLAGS) $(EXTRA_LDFLAGS)" \
       "$(core-y)" \
       "$(libs-y)" \

Modified: trunk/busybox/Makefile.flags
===================================================================
--- trunk/busybox/Makefile.flags	2008-06-04 10:33:33 UTC (rev 22210)
+++ trunk/busybox/Makefile.flags	2008-06-04 11:28:24 UTC (rev 22211)
@@ -50,19 +50,33 @@
 CFLAGS += $(call cc-option,-g)
 endif
 
+# If arch/$(ARCH)/Makefile did not override it (with, say, -fPIC)...
+ARCH_FPIC ?= -fpic
+ARCH_FPIE ?= -fpie
+ARCH_PIE ?= -pie
+
 ifeq ($(CONFIG_BUILD_LIBBUSYBOX),y)
 # on i386: 14% smaller libbusybox.so
 # (code itself is 9% bigger, we save on relocs/PLT/GOT)
-CFLAGS += -fpic
+CFLAGS += $(ARCH_FPIC)
 # and another 4% reduction of libbusybox.so:
 # (external entry points must be marked EXTERNALLY_VISIBLE)
 CFLAGS += $(call cc-option,-fvisibility=hidden)
 endif
 
 ifeq ($(CONFIG_STATIC),y)
-LDFLAGS += -static
+CFLAGS_busybox += -static
 endif
 
+ifeq ($(CONFIG_PIE),y)
+CFLAGS_busybox += $(ARCH_PIE)
+CFLAGS += $(ARCH_FPIE)
+# No switch() jump tables. Code growth +1k, binary size down -12k
+# due to reduced number of code pointers.
+# (TODO: make overridable: some arches may want to not do this)
+CFLAGS += $(call cc-option,-fno-jump-tables)
+endif
+
 LDLIBS += m crypt
 
 ifeq ($(CONFIG_PAM),y)
@@ -81,8 +95,6 @@
 LDLIBS += dmalloc
 endif
 
-#LDFLAGS += -nostdlib
-
 LDFLAGS_ELF2FLT = -Wl,-elf2flt
 ifneq (,$(findstring $(LDFLAGS_ELF2FLT),$(LDFLAGS)))
 SKIP_STRIP = y

Modified: trunk/busybox/scripts/Makefile.IMA
===================================================================
--- trunk/busybox/scripts/Makefile.IMA	2008-06-04 10:33:33 UTC (rev 22210)
+++ trunk/busybox/scripts/Makefile.IMA	2008-06-04 11:28:24 UTC (rev 22211)
@@ -45,8 +45,8 @@
 OBJCOPY         = $(CROSS_COMPILE)objcopy
 OBJDUMP         = $(CROSS_COMPILE)objdump
 
-CFLAGS := $(CFLAGS)
-CPPFLAGS+= -D"KBUILD_STR(s)=\#s" #-Q
+CFLAGS   := $(CFLAGS)
+CPPFLAGS += -D"KBUILD_STR(s)=\#s" #-Q
 
 # We need some generic definitions
 include $(srctree)/scripts/Kbuild.include
@@ -180,7 +180,7 @@
 busybox: busybox_unstripped.o
 	$(srctree)/scripts/trylink \
 		busybox_unstripped \
-		"$(CC)" \
+		"$(CC) $(CFLAGS_busybox)" \
 		"$(CFLAGS)" \
 		"$(LDFLAGS)" \
 		"busybox_unstripped.o" \

Modified: trunk/busybox/scripts/Makefile.build
===================================================================
--- trunk/busybox/scripts/Makefile.build	2008-06-04 10:33:33 UTC (rev 22210)
+++ trunk/busybox/scripts/Makefile.build	2008-06-04 11:28:24 UTC (rev 22211)
@@ -251,8 +251,8 @@
 quiet_cmd_link_o_target = LD      $@
 # If the list of objects to link is empty, just create an empty built-in.o
 cmd_link_o_target = $(if $(strip $(obj-y)),\
-		      $(LD) $(ld_flags) -r -o $@ $(filter $(obj-y), $^),\
-		      rm -f $@; $(AR) rcs $@)
+		$(LD) $(ld_flags) -r -o $@ $(filter $(obj-y), $^),\
+		rm -f $@; $(AR) rcs $@)
 
 $(builtin-target): $(obj-y) FORCE
 	$(call if_changed,link_o_target)