Commit f309b4ba authored by Andrii Nakryiko's avatar Andrii Nakryiko
Browse files

Merge branch 'libbpf: rename btf__get_from_id() and btf__load() APIs, support split BTF' 

Quentin Monnet says:

====================

As part of the effort to move towards a v1.0 for libbpf [0], this set
improves some confusing function names related to BTF loading from and to
the kernel:

- btf__load() becomes btf__load_into_kernel().
- btf__get_from_id becomes btf__load_from_kernel_by_id().
- A new version btf__load_from_kernel_by_id_split() extends the former to
  add support for split BTF.

The last patch is a trivial change to bpftool to add support for dumping
split BTF objects by referencing them by their id (and not only by their
BTF path).

[0] https://github.com/libbpf/libbpf/wiki/Libbpf:-the-road-to-v1.0#btfh-apis



v3:
- Use libbpf_err_ptr() in btf__load_from_kernel_by_id(), ERR_PTR() in
  bpftool's get_map_kv_btf().
- Move the definition of btf__load_from_kernel_by_id() closer to the
  btf__parse() group in btf.h (move the legacy function with it).
- Fix a bug on the return value in libbpf_find_prog_btf_id(), as a new
  patch.
- Move the btf__free() fixes to their own patch.
- Add "Fixes:" tags to relevant patches.

v2:
- Remove deprecation marking of legacy functions (patch 4/6 from v1).
- Make btf__load_from_kernel_by_id{,_split}() return the btf struct, adjust
  surrounding code and call btf__free() when missing.
- Add new functions to v0.5.0 API (and not v0.6.0).
====================

Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
parents d3621642 211ab78f

tools/bpf/bpftool/btf.c

+2 −6
Original line number Diff line number Diff line
@@ -580,16 +580,12 @@ static int do_dump(int argc, char **argv) 
	}



	if (!btf) {

		err = btf__get_from_id(btf_id, &btf);

		btf = btf__load_from_kernel_by_id_split(btf_id, base_btf);

		err = libbpf_get_error(btf);

		if (err) {

			p_err("get btf by id (%u): %s", btf_id, strerror(err));

			goto done;

		}

		if (!btf) {

			err = -ENOENT;

			p_err("can't find btf with ID (%u)", btf_id);

			goto done;

		}

	}



	if (dump_c) {

tools/bpf/bpftool/btf_dumper.c

+4 −2
Original line number Diff line number Diff line
@@ -64,8 +64,10 @@ static int dump_prog_id_as_func_ptr(const struct btf_dumper *d, 
	}

	info = &prog_info->info;



	if (!info->btf_id || !info->nr_func_info ||

	    btf__get_from_id(info->btf_id, &prog_btf))

	if (!info->btf_id || !info->nr_func_info)

		goto print;

	prog_btf = btf__load_from_kernel_by_id(info->btf_id);

	if (libbpf_get_error(prog_btf))

		goto print;

	finfo = u64_to_ptr(info->func_info);

	func_type = btf__type_by_id(prog_btf, finfo->type_id);

tools/bpf/bpftool/map.c

+7 −7
Original line number Diff line number Diff line
@@ -807,10 +807,11 @@ static struct btf *get_map_kv_btf(const struct bpf_map_info *info) 
	} else if (info->btf_value_type_id) {

		int err;



		err = btf__get_from_id(info->btf_id, &btf);

		if (err || !btf) {

		btf = btf__load_from_kernel_by_id(info->btf_id);

		err = libbpf_get_error(btf);

		if (err) {

			p_err("failed to get btf");

			btf = err ? ERR_PTR(err) : ERR_PTR(-ESRCH);

			btf = ERR_PTR(err);

		}

	}
@@ -1039,11 +1040,10 @@ static void print_key_value(struct bpf_map_info *info, void *key, 
			    void *value)

{

	json_writer_t *btf_wtr;

	struct btf *btf = NULL;

	int err;

	struct btf *btf;



	err = btf__get_from_id(info->btf_id, &btf);

	if (err) {

	btf = btf__load_from_kernel_by_id(info->btf_id);

	if (libbpf_get_error(btf)) {

		p_err("failed to get btf");

		return;

	}

tools/bpf/bpftool/prog.c

+20 −9
Original line number Diff line number Diff line
@@ -249,10 +249,10 @@ static void show_prog_metadata(int fd, __u32 num_maps) 
	struct bpf_map_info map_info;

	struct btf_var_secinfo *vsi;

	bool printed_header = false;

	struct btf *btf = NULL;

	unsigned int i, vlen;

	void *value = NULL;

	const char *name;

	struct btf *btf;

	int err;



	if (!num_maps)
@@ -263,8 +263,8 @@ static void show_prog_metadata(int fd, __u32 num_maps) 
	if (!value)

		return;



	err = btf__get_from_id(map_info.btf_id, &btf);

	if (err || !btf)

	btf = btf__load_from_kernel_by_id(map_info.btf_id);

	if (libbpf_get_error(btf))

		goto out_free;



	t_datasec = btf__type_by_id(btf, map_info.btf_value_type_id);
@@ -646,10 +646,13 @@ prog_dump(struct bpf_prog_info *info, enum dump_mode mode, 
		member_len = info->xlated_prog_len;

	}



	if (info->btf_id && btf__get_from_id(info->btf_id, &btf)) {

	if (info->btf_id) {

		btf = btf__load_from_kernel_by_id(info->btf_id);

		if (libbpf_get_error(btf)) {

			p_err("failed to get btf");

			return -1;

		}

	}



	func_info = u64_to_ptr(info->func_info);
@@ -781,6 +784,8 @@ prog_dump(struct bpf_prog_info *info, enum dump_mode mode, 
		kernel_syms_destroy(&dd);

	}



	btf__free(btf);



	return 0;

}
@@ -2002,8 +2007,8 @@ static char *profile_target_name(int tgt_fd) 
	struct bpf_prog_info_linear *info_linear;

	struct bpf_func_info *func_info;

	const struct btf_type *t;

	struct btf *btf = NULL;

	char *name = NULL;

	struct btf *btf;



	info_linear = bpf_program__get_prog_info_linear(

		tgt_fd, 1UL << BPF_PROG_INFO_FUNC_INFO);
@@ -2012,12 +2017,17 @@ static char *profile_target_name(int tgt_fd) 
		return NULL;

	}



	if (info_linear->info.btf_id == 0 ||

	    btf__get_from_id(info_linear->info.btf_id, &btf)) {

	if (info_linear->info.btf_id == 0) {

		p_err("prog FD %d doesn't have valid btf", tgt_fd);

		goto out;

	}



	btf = btf__load_from_kernel_by_id(info_linear->info.btf_id);

	if (libbpf_get_error(btf)) {

		p_err("failed to load btf for prog FD %d", tgt_fd);

		goto out;

	}



	func_info = u64_to_ptr(info_linear->info.func_info);

	t = btf__type_by_id(btf, func_info[0].type_id);

	if (!t) {
@@ -2027,6 +2037,7 @@ static char *profile_target_name(int tgt_fd) 
	}

	name = strdup(btf__name_by_offset(btf, t->name_off));

out:

	btf__free(btf);

	free(info_linear);

	return name;

}

tools/lib/bpf/btf.c

+24 −9
Original line number Diff line number Diff line
@@ -1180,7 +1180,7 @@ int btf__finalize_data(struct bpf_object *obj, struct btf *btf) 


static void *btf_get_raw_data(const struct btf *btf, __u32 *size, bool swap_endian);



int btf__load(struct btf *btf)

int btf__load_into_kernel(struct btf *btf)

{

	__u32 log_buf_size = 0, raw_size;

	char *log_buf = NULL;
@@ -1228,6 +1228,7 @@ int btf__load(struct btf *btf) 
	free(log_buf);

	return libbpf_err(err);

}

int btf__load(struct btf *) __attribute__((alias("btf__load_into_kernel")));



int btf__fd(const struct btf *btf)

{
@@ -1382,21 +1383,35 @@ struct btf *btf_get_from_fd(int btf_fd, struct btf *base_btf) 
	return btf;

}



int btf__get_from_id(__u32 id, struct btf **btf)

struct btf *btf__load_from_kernel_by_id_split(__u32 id, struct btf *base_btf)

{

	struct btf *res;

	int err, btf_fd;

	struct btf *btf;

	int btf_fd;



	*btf = NULL;

	btf_fd = bpf_btf_get_fd_by_id(id);

	if (btf_fd < 0)

		return libbpf_err(-errno);



	res = btf_get_from_fd(btf_fd, NULL);

	err = libbpf_get_error(res);

		return libbpf_err_ptr(-errno);



	btf = btf_get_from_fd(btf_fd, base_btf);

	close(btf_fd);



	return libbpf_ptr(btf);

}



struct btf *btf__load_from_kernel_by_id(__u32 id)

{

	return btf__load_from_kernel_by_id_split(id, NULL);

}



int btf__get_from_id(__u32 id, struct btf **btf)

{

	struct btf *res;

	int err;



	*btf = NULL;

	res = btf__load_from_kernel_by_id(id);

	err = libbpf_get_error(res);



	if (err)

		return libbpf_err(err);