musl/crt/rcrt1.c

#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(*)());

__attribute__((__visibility__("hidden")))
_Noreturn void __dls2(unsigned char *base, size_t *sp)
{
	__libc_start_main(main, *sp, (void *)(sp+1), _init, _fini, 0);
}
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. 2015-05-26 03:37:41 -04:00			`#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(*)());`

fix visibility mismatch in dynamic linker stage 2 function definition since commits 2907afb8dbd4c1d34825c3c9bd2b41564baca210 and 6fc30c2493fcfedec89e45088bea87766a1e3286, __dls2 is no longer called via symbol lookup, but instead uses relative addressing that needs to be resolved at link time. on some linker versions, and/or if -Bsymbolic-functions is not used, the linker may leave behind a dynamic relocation, which is not suitable for bootstrapping the dynamic linker, if the reference to __dls2 is marked hidden but the definition is not actually hidden. correcting the definition to use hidden visibility fixes the problem. the static-PIE entry point rcrt1 was likewise affected and is also fixed by this patch. 2015-10-15 17:38:54 -04:00			`__attribute__((__visibility__("hidden")))`
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. 2015-05-26 03:37:41 -04:00			`_Noreturn void __dls2(unsigned char base, size_t sp)`
			`{`
			`__libc_start_main(main, sp, (void )(sp+1), _init, _fini, 0);`
			`}`