Commit c76e4c22 authored by Taeung Song's avatar Taeung Song Committed by Daniel Borkmann
Browse files

libbpf: Show supported ELF section names when failing to guess prog/attach type 



We need to let users check their wrong ELF section name with proper
ELF section names when they fail to get a prog/attach type from it.
Because users can't realize libbpf guess prog/attach types from given
ELF section names. For example, when a 'cgroup' section name of a
BPF program is used, show available ELF section names(types).

Before:

    $ bpftool prog load bpf-prog.o /sys/fs/bpf/prog1
    Error: failed to guess program type based on ELF section name cgroup

After:

    libbpf: failed to guess program type based on ELF section name 'cgroup'
    libbpf: supported section(type) names are: socket kprobe/ kretprobe/ classifier action tracepoint/ raw_tracepoint/ xdp perf_event lwt_in lwt_out lwt_xmit lwt_seg6local cgroup_skb/ingress cgroup_skb/egress cgroup/skb cgroup/sock cgroup/post_bind4 cgroup/post_bind6 cgroup/dev sockops sk_skb/stream_parser sk_skb/stream_verdict sk_skb sk_msg lirc_mode2 flow_dissector cgroup/bind4 cgroup/bind6 cgroup/connect4 cgroup/connect6 cgroup/sendmsg4 cgroup/sendmsg6

Signed-off-by: default avatarTaeung Song <treeze.taeung@gmail.com>
Cc: Quentin Monnet <quentin.monnet@netronome.com>
Cc: Jakub Kicinski <jakub.kicinski@netronome.com>
Cc: Andrey Ignatov <rdna@fb.com>
Reviewed-by: default avatarQuentin Monnet <quentin.monnet@netronome.com>
Acked-by: default avatarJakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent ffcf7ce9

tools/bpf/bpftool/prog.c

+3 −7
Original line number Diff line number Diff line
@@ -930,10 +930,9 @@ static int load_with_options(int argc, char **argv, bool first_prog_only) 
			err = libbpf_prog_type_by_name(type, &attr.prog_type,

						       &expected_attach_type);

			free(type);

			if (err < 0) {

				p_err("unknown program type '%s'", *argv);

			if (err < 0)

				goto err_free_reuse_maps;

			}



			NEXT_ARG();

		} else if (is_prefix(*argv, "map")) {

			void *new_map_replace;
@@ -1028,12 +1027,9 @@ static int load_with_options(int argc, char **argv, bool first_prog_only) 


			err = libbpf_prog_type_by_name(sec_name, &prog_type,

						       &expected_attach_type);

			if (err < 0) {

				p_err("failed to guess program type based on section name %s\n",

				      sec_name);

			if (err < 0)

				goto err_close_obj;

		}

		}



		bpf_program__set_ifindex(pos, ifindex);

		bpf_program__set_type(pos, prog_type);

tools/lib/bpf/libbpf.c

+44 −2
Original line number Diff line number Diff line
@@ -2667,9 +2667,38 @@ static const struct { 
#undef BPF_EAPROG_SEC

#undef BPF_APROG_COMPAT



#define MAX_TYPE_NAME_SIZE 32



static char *libbpf_get_type_names(bool attach_type)

{

	int i, len = ARRAY_SIZE(section_names) * MAX_TYPE_NAME_SIZE;

	char *buf;



	buf = malloc(len);

	if (!buf)

		return NULL;



	buf[0] = '\0';

	/* Forge string buf with all available names */

	for (i = 0; i < ARRAY_SIZE(section_names); i++) {

		if (attach_type && !section_names[i].is_attachable)

			continue;



		if (strlen(buf) + strlen(section_names[i].sec) + 2 > len) {

			free(buf);

			return NULL;

		}

		strcat(buf, " ");

		strcat(buf, section_names[i].sec);

	}



	return buf;

}



int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,

			     enum bpf_attach_type *expected_attach_type)

{

	char *type_names;

	int i;



	if (!name)
@@ -2682,12 +2711,20 @@ int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type, 
		*expected_attach_type = section_names[i].expected_attach_type;

		return 0;

	}

	pr_warning("failed to guess program type based on ELF section name '%s'\n", name);

	type_names = libbpf_get_type_names(false);

	if (type_names != NULL) {

		pr_info("supported section(type) names are:%s\n", type_names);

		free(type_names);

	}



	return -EINVAL;

}



int libbpf_attach_type_by_name(const char *name,

			       enum bpf_attach_type *attach_type)

{

	char *type_names;

	int i;



	if (!name)
@@ -2701,6 +2738,13 @@ int libbpf_attach_type_by_name(const char *name, 
		*attach_type = section_names[i].attach_type;

		return 0;

	}

	pr_warning("failed to guess attach type based on ELF section name '%s'\n", name);

	type_names = libbpf_get_type_names(true);

	if (type_names != NULL) {

		pr_info("attachable section(type) names are:%s\n", type_names);

		free(type_names);

	}



	return -EINVAL;

}
@@ -2907,8 +2951,6 @@ int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr, 
			err = bpf_program__identify_section(prog, &prog_type,

							    &expected_attach_type);

			if (err < 0) {

				pr_warning("failed to guess program type based on section name %s\n",

					   prog->section_name);

				bpf_object__close(obj);

				return -EINVAL;

			}

tools/testing/selftests/bpf/test_socket_cookie.c

+1 −3
Original line number Diff line number Diff line
@@ -158,10 +158,8 @@ static int run_test(int cgfd) 
	bpf_object__for_each_program(prog, pobj) {

		prog_name = bpf_program__title(prog, /*needs_copy*/ false);



		if (libbpf_attach_type_by_name(prog_name, &attach_type)) {

			log_err("Unexpected prog: %s", prog_name);

		if (libbpf_attach_type_by_name(prog_name, &attach_type))

			goto err;

		}



		err = bpf_prog_attach(bpf_program__fd(prog), cgfd, attach_type,

				      BPF_F_ALLOW_OVERRIDE);

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