Commit fdbf5dde authored by Andrii Nakryiko's avatar Andrii Nakryiko Committed by Alexei Starovoitov
Browse files

libbpf: Add per-file linker opts 



For better future extensibility add per-file linker options. Currently
the set of available options is empty. This changes bpf_linker__add_file()
API, but it's not a breaking change as bpf_linker APIs hasn't been released
yet.

Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210507054119.270888-3-andrii@kernel.org
parent 37f05601

tools/bpf/bpftool/gen.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -638,7 +638,7 @@ static int do_object(int argc, char **argv) 
	while (argc) {

	while (argc) {

		file = GET_ARG();

		file = GET_ARG();





		err = bpf_linker__add_file(linker, file);

		err = bpf_linker__add_file(linker, file, NULL);

		if (err) {

		if (err) {

			p_err("failed to link '%s': %s (%d)", file, strerror(err), err);

			p_err("failed to link '%s': %s (%d)", file, strerror(err), err);

			goto out;

			goto out;

tools/lib/bpf/libbpf.h

+9 −1
Original line number Original line Diff line number Diff line
@@ -768,10 +768,18 @@ struct bpf_linker_opts { 
};

};

#define bpf_linker_opts__last_field sz

#define bpf_linker_opts__last_field sz





struct bpf_linker_file_opts {

	/* size of this struct, for forward/backward compatiblity */

	size_t sz;

};

#define bpf_linker_file_opts__last_field sz



struct bpf_linker;

struct bpf_linker;





LIBBPF_API struct bpf_linker *bpf_linker__new(const char *filename, struct bpf_linker_opts *opts);

LIBBPF_API struct bpf_linker *bpf_linker__new(const char *filename, struct bpf_linker_opts *opts);

LIBBPF_API int bpf_linker__add_file(struct bpf_linker *linker, const char *filename);

LIBBPF_API int bpf_linker__add_file(struct bpf_linker *linker,

				    const char *filename,

				    const struct bpf_linker_file_opts *opts);

LIBBPF_API int bpf_linker__finalize(struct bpf_linker *linker);

LIBBPF_API int bpf_linker__finalize(struct bpf_linker *linker);

LIBBPF_API void bpf_linker__free(struct bpf_linker *linker);

LIBBPF_API void bpf_linker__free(struct bpf_linker *linker);

tools/lib/bpf/linker.c

+12 −4
Original line number Original line Diff line number Diff line
@@ -158,7 +158,9 @@ struct bpf_linker { 




static int init_output_elf(struct bpf_linker *linker, const char *file);

static int init_output_elf(struct bpf_linker *linker, const char *file);





static int linker_load_obj_file(struct bpf_linker *linker, const char *filename, struct src_obj *obj);

static int linker_load_obj_file(struct bpf_linker *linker, const char *filename,

				const struct bpf_linker_file_opts *opts,

				struct src_obj *obj);

static int linker_sanity_check_elf(struct src_obj *obj);

static int linker_sanity_check_elf(struct src_obj *obj);

static int linker_sanity_check_elf_symtab(struct src_obj *obj, struct src_sec *sec);

static int linker_sanity_check_elf_symtab(struct src_obj *obj, struct src_sec *sec);

static int linker_sanity_check_elf_relos(struct src_obj *obj, struct src_sec *sec);

static int linker_sanity_check_elf_relos(struct src_obj *obj, struct src_sec *sec);
@@ -435,15 +437,19 @@ static int init_output_elf(struct bpf_linker *linker, const char *file) 
	return 0;

	return 0;

}

}





int bpf_linker__add_file(struct bpf_linker *linker, const char *filename)

int bpf_linker__add_file(struct bpf_linker *linker, const char *filename,

			 const struct bpf_linker_file_opts *opts)

{

{

	struct src_obj obj = {};

	struct src_obj obj = {};

	int err = 0;

	int err = 0;





	if (!OPTS_VALID(opts, bpf_linker_file_opts))

		return -EINVAL;



	if (!linker->elf)

	if (!linker->elf)

		return -EINVAL;

		return -EINVAL;





	err = err ?: linker_load_obj_file(linker, filename, &obj);

	err = err ?: linker_load_obj_file(linker, filename, opts, &obj);

	err = err ?: linker_append_sec_data(linker, &obj);

	err = err ?: linker_append_sec_data(linker, &obj);

	err = err ?: linker_append_elf_syms(linker, &obj);

	err = err ?: linker_append_elf_syms(linker, &obj);

	err = err ?: linker_append_elf_relos(linker, &obj);

	err = err ?: linker_append_elf_relos(linker, &obj);
@@ -529,7 +535,9 @@ static struct src_sec *add_src_sec(struct src_obj *obj, const char *sec_name) 
	return sec;

	return sec;

}

}





static int linker_load_obj_file(struct bpf_linker *linker, const char *filename, struct src_obj *obj)

static int linker_load_obj_file(struct bpf_linker *linker, const char *filename,

				const struct bpf_linker_file_opts *opts,

				struct src_obj *obj)

{

{

#if __BYTE_ORDER == __LITTLE_ENDIAN

#if __BYTE_ORDER == __LITTLE_ENDIAN

	const int host_endianness = ELFDATA2LSB;

	const int host_endianness = ELFDATA2LSB;