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| author | Rich Felker <dalias@aerifal.cx> | 2015-05-26 03:37:41 -0400 |
|---|---|---|
| committer | Rich Felker <dalias@aerifal.cx> | 2015-05-26 03:37:41 -0400 |
| commit | dc031ee0b1ba11baa00cd7f0769e461a5f396c71 (patch) | |
| tree | 2d157d390496596007e366af3403745db2d39ac1 | |
| parent | ed0c8249825161036356a3616e8c5247c15d0927 (diff) | |
| download | musl-dc031ee0b1ba11baa00cd7f0769e461a5f396c71.tar.gz musl-dc031ee0b1ba11baa00cd7f0769e461a5f396c71.tar.xz musl-dc031ee0b1ba11baa00cd7f0769e461a5f396c71.zip | |
add rcrt1 start file for fully static-linked PIE
static-linked PIE files need startup code to relocate themselves, much like the dynamic linker does. rcrt1.c reuses the code in dlstart.c, stage 1 of the dynamic linker, which in turn reuses crt_arch.h, to achieve static PIE with no new code. only relative relocations are supported. existing toolchains that don't yet support static PIE directly can be repurposed by passing "-shared -Wl,-Bstatic -Wl,-Bsymbolic" instead of "-static -pie" and substituting rcrt1.o in place of crt1.o. all libraries being linked must be built as PIC/PIE; TEXTRELs are not supported at this time.
| -rw-r--r-- | Makefile | 4 | ||||
| -rw-r--r-- | crt/rcrt1.c | 15 |
2 files changed, 17 insertions, 2 deletions
diff --git a/Makefile b/Makefile index b9668b43..3bd7b4d7 100644 --- a/Makefile +++ b/Makefile @@ -44,7 +44,7 @@ ALL_INCLUDES = $(sort $(wildcard include/*.h include/*/*.h) $(GENH) $(ARCH_INCLU EMPTY_LIB_NAMES = m rt pthread crypt util xnet resolv dl EMPTY_LIBS = $(EMPTY_LIB_NAMES:%=lib/lib%.a) -CRT_LIBS = lib/crt1.o lib/Scrt1.o lib/crti.o lib/crtn.o +CRT_LIBS = lib/crt1.o lib/Scrt1.o lib/rcrt1.o lib/crti.o lib/crtn.o STATIC_LIBS = lib/libc.a SHARED_LIBS = lib/libc.so TOOL_LIBS = lib/musl-gcc.specs @@ -89,7 +89,7 @@ src/ldso/dlstart.lo src/ldso/dynlink.lo: src/internal/dynlink.h arch/$(ARCH)/rel crt/crt1.o crt/Scrt1.o src/ldso/dlstart.lo: $(wildcard arch/$(ARCH)/crt_arch.h) -crt/Scrt1.o: CFLAGS += -fPIC +crt/Scrt1.o crt/rcrt1.o: CFLAGS += -fPIC OPTIMIZE_SRCS = $(wildcard $(OPTIMIZE_GLOBS:%=src/%)) $(OPTIMIZE_SRCS:%.c=%.o) $(OPTIMIZE_SRCS:%.c=%.lo): CFLAGS += -O3 diff --git a/crt/rcrt1.c b/crt/rcrt1.c new file mode 100644 index 00000000..5ac612db --- /dev/null +++ b/crt/rcrt1.c @@ -0,0 +1,15 @@ +#define SHARED +#define START "_start" +#define _dlstart_c _start_c +#include "../src/ldso/dlstart.c" + +int main(); +void _init() __attribute__((weak)); +void _fini() __attribute__((weak)); +_Noreturn int __libc_start_main(int (*)(), int, char **, + void (*)(), void(*)(), void(*)()); + +_Noreturn void __dls2(unsigned char *base, size_t *sp) +{ + __libc_start_main(main, *sp, (void *)(sp+1), _init, _fini, 0); +} |