Commit fa452837 authored by Andrii Nakryiko's avatar Andrii Nakryiko Committed by Alexei Starovoitov
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tools/bpftool: Auto-detect split BTFs in common cases 



In case of working with module's split BTF from /sys/kernel/btf/*,
auto-substitute /sys/kernel/btf/vmlinux as the base BTF. This makes using
bpftool with module BTFs faster and simpler.

Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20201202065244.530571-4-andrii@kernel.org
parent 0cfdcd63

tools/bpf/bpftool/btf.c

+21 −4
Original line number Diff line number Diff line
@@ -357,11 +357,13 @@ static int dump_btf_raw(const struct btf *btf, 
			dump_btf_type(btf, root_type_ids[i], t);

		}

	} else {

		const struct btf *base;

		int cnt = btf__get_nr_types(btf);

		int start_id = 1;



		if (base_btf)

			start_id = btf__get_nr_types(base_btf) + 1;

		base = btf__base_btf(btf);

		if (base)

			start_id = btf__get_nr_types(base) + 1;



		for (i = start_id; i <= cnt; i++) {

			t = btf__type_by_id(btf, i);
@@ -428,7 +430,7 @@ static int dump_btf_c(const struct btf *btf, 


static int do_dump(int argc, char **argv)

{

	struct btf *btf = NULL;

	struct btf *btf = NULL, *base = NULL;

	__u32 root_type_ids[2];

	int root_type_cnt = 0;

	bool dump_c = false;
@@ -502,7 +504,21 @@ static int do_dump(int argc, char **argv) 
		}

		NEXT_ARG();

	} else if (is_prefix(src, "file")) {

		btf = btf__parse_split(*argv, base_btf);

		const char sysfs_prefix[] = "/sys/kernel/btf/";

		const char sysfs_vmlinux[] = "/sys/kernel/btf/vmlinux";



		if (!base_btf &&

		    strncmp(*argv, sysfs_prefix, sizeof(sysfs_prefix) - 1) == 0 &&

		    strcmp(*argv, sysfs_vmlinux) != 0) {

			base = btf__parse(sysfs_vmlinux, NULL);

			if (libbpf_get_error(base)) {

				p_err("failed to parse vmlinux BTF at '%s': %ld\n",

				      sysfs_vmlinux, libbpf_get_error(base));

				base = NULL;

			}

		}



		btf = btf__parse_split(*argv, base ?: base_btf);

		if (IS_ERR(btf)) {

			err = -PTR_ERR(btf);

			btf = NULL;
@@ -567,6 +583,7 @@ static int do_dump(int argc, char **argv) 
done:

	close(fd);

	btf__free(btf);

	btf__free(base);

	return err;

}