Commit 05a06be7 authored by Quentin Monnet's avatar Quentin Monnet Committed by Alexei Starovoitov
Browse files

bpftool: Return an error on prog dumps if both CFG and JSON are required 



We do not support JSON output for control flow graphs of programs with
bpftool. So far, requiring both the CFG and JSON output would result in
producing a null JSON object. It makes more sense to raise an error
directly when parsing command line arguments and options, so that users
know they won't get any output they might expect.

If JSON is required for the graph, we leave it to Graphviz instead:

    # bpftool prog dump xlated <REF> visual | dot -Tjson

Suggested-by: default avatarEduard Zingerman <eddyz87@gmail.com>
Signed-off-by: default avatarQuentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/r/20230405132120.59886-5-quentin@isovalent.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 9fd49684

tools/bpf/bpftool/bash-completion/bpftool

+6 −3
Original line number Diff line number Diff line
@@ -255,7 +255,7 @@ _bpftool_map_update_get_name() 


_bpftool()

{

    local cur prev words objword

    local cur prev words objword json=0

    _init_completion || return



    # Deal with options
@@ -265,6 +265,9 @@ _bpftool() 
        COMPREPLY=( $( compgen -W "$c" -- "$cur" ) )

        return 0

    fi

    if _bpftool_search_list -j --json -p --pretty; then

        json=1

    fi



    # Deal with simplest keywords

    case $prev in
@@ -367,7 +370,7 @@ _bpftool() 
                            ;;

                        *)

                            _bpftool_once_attr 'file'

                            if _bpftool_search_list 'xlated'; then

                            if _bpftool_search_list 'xlated' && [[ "$json" == 0 ]]; then

                                COMPREPLY+=( $( compgen -W 'opcodes visual linum' -- \

                                    "$cur" ) )

                            else

tools/bpf/bpftool/prog.c

+5 −3
Original line number Diff line number Diff line
@@ -849,9 +849,7 @@ prog_dump(struct bpf_prog_info *info, enum dump_mode mode, 
		dd.finfo_rec_size = info->func_info_rec_size;

		dd.prog_linfo = prog_linfo;



		if (json_output && visual)

			jsonw_null(json_wtr);

		else if (json_output)

		if (json_output)

			dump_xlated_json(&dd, buf, member_len, opcodes, linum);

		else if (visual)

			dump_xlated_cfg(&dd, buf, member_len);
@@ -940,6 +938,10 @@ static int do_dump(int argc, char **argv) 
		usage();

		goto exit_close;

	}

	if (json_output && visual) {

		p_err("'visual' is not compatible with JSON output");

		goto exit_close;

	}



	if (json_output && nb_fds > 1)

		jsonw_start_array(json_wtr);	/* root array */