freebsd-skq/libexec/rtld-elf/Makefile
emaste 33a9dab77f Add WITH_PIE knob to build Position Independent Executables
Building binaries as PIE allows the executable itself to be loaded at a
random address when ASLR is enabled (not just its shared libraries).

With this change PIE objects have a .pieo extension and INTERNALLIB
libraries libXXX_pie.a.

MK_PIE is disabled for some kerberos5 tools, Clang, and Subversion, as
they explicitly reference .a libraries in their Makefiles.  These can
be addressed on an individual basis later.  MK_PIE is also disabled for
rtld-elf because it is already position-independent using bespoke
Makefile rules.

Currently only dynamically linked binaries will be built as PIE.

Discussed with:	dim
Reviewed by:	kib
MFC after:	1 month
Relnotes:	Yes
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D18423
2019-02-15 22:22:38 +00:00

120 lines
2.8 KiB
Makefile

# $FreeBSD$
# Use the following command to build local debug version of dynamic
# linker:
# make DEBUG_FLAGS=-g DEBUG=-DDEBUG WITHOUT_TESTS=yes all
.include <src.opts.mk>
PACKAGE= clibs
MK_BIND_NOW= no
MK_PIE= no # Always position independent using local rules
MK_SSP= no
CONFS= libmap.conf
PROG?= ld-elf.so.1
.if (${PROG:M*ld-elf32*} != "")
TAGS+= lib32
.endif
SRCS= \
rtld_start.S \
reloc.c \
rtld.c \
rtld_lock.c \
rtld_malloc.c \
rtld_printf.c \
map_object.c \
xmalloc.c \
debug.c \
libmap.c
MAN= rtld.1
CSTD?= gnu99
CFLAGS+= -Wall -DFREEBSD_ELF -DIN_RTLD -ffreestanding
CFLAGS+= -I${SRCTOP}/lib/csu/common
.if exists(${.CURDIR}/${MACHINE_ARCH})
RTLD_ARCH= ${MACHINE_ARCH}
.else
RTLD_ARCH= ${MACHINE_CPUARCH}
.endif
CFLAGS+= -I${.CURDIR}/${RTLD_ARCH} -I${.CURDIR}
.if ${MACHINE_ARCH} == "powerpc64"
LDFLAGS+= -nostdlib -e _rtld_start
.else
LDFLAGS+= -nostdlib -e .rtld_start
.endif
NO_WCAST_ALIGN= yes
WARNS?= 6
INSTALLFLAGS= -C -b
PRECIOUSPROG=
BINDIR= /libexec
SYMLINKS= ../..${BINDIR}/${PROG} ${LIBEXECDIR}/${PROG}
MLINKS= rtld.1 ld-elf.so.1.1 \
rtld.1 ld.so.1
.if ${MACHINE_CPUARCH} == "sparc64"
CFLAGS+= -fPIC
.else
CFLAGS+= -fpic
.endif
CFLAGS+= -DPIC $(DEBUG)
.if ${MACHINE_CPUARCH} == "amd64" || ${MACHINE_CPUARCH} == "i386"
CFLAGS+= -fvisibility=hidden
.endif
.if ${MACHINE_CPUARCH} == "mips"
CFLAGS.reloc.c+=-fno-jump-tables
.endif
LDFLAGS+= -shared -Wl,-Bsymbolic -Wl,-z,defs
LIBADD= c_nossp_pic
.if ${MK_TOOLCHAIN} == "no"
LDFLAGS+= -L${LIBCDIR}
.endif
.if ${MACHINE_CPUARCH} == "arm"
# Some of the required math functions (div & mod) are implemented in
# libcompiler_rt on ARM. The library also needs to be placed first to be
# correctly linked. As some of the functions are used before we have
# shared libraries.
LIBADD+= compiler_rt
.endif
.if ${MK_SYMVER} == "yes"
VERSION_DEF= ${LIBCSRCDIR}/Versions.def
SYMBOL_MAPS= ${.CURDIR}/Symbol.map
VERSION_MAP= Version.map
LDFLAGS+= -Wl,--version-script=${VERSION_MAP}
.if exists(${.CURDIR}/${RTLD_ARCH}/Symbol.map)
SYMBOL_MAPS+= ${.CURDIR}/${RTLD_ARCH}/Symbol.map
.endif
.endif
.sinclude "${.CURDIR}/${RTLD_ARCH}/Makefile.inc"
# Since moving rtld-elf to /libexec, we need to create a symlink.
# Fixup the existing binary that's there so we can symlink over it.
beforeinstall:
.if exists(${DESTDIR}/usr/libexec/${PROG}) && ${MK_STAGING} == "no"
-chflags -h noschg ${DESTDIR}/usr/libexec/${PROG}
.endif
.PATH: ${.CURDIR}/${RTLD_ARCH}
HAS_TESTS=
SUBDIR.${MK_TESTS}+= tests
.include <bsd.prog.mk>
${PROG_FULL}: ${VERSION_MAP}
.include <bsd.symver.mk>
.if ${COMPILER_TYPE} == "gcc"
# GCC warns about redeclarations even though they have __exported
# and are therefore not identical to the ones from the system headers.
CFLAGS+= -Wno-redundant-decls
.if ${COMPILER_VERSION} < 40300
# Silence -Wshadow false positives in ancient GCC
CFLAGS+= -Wno-shadow
.endif
.endif