tools: bpftool: Print optional built-in features along with version (82b8cf0a) · Commits · 戴 / test

Bpftool has a number of features that can be included or left aside during compilation. This includes: - Support for libbfd, providing the disassembler for JIT-compiled programs. - Support for BPF skeletons, used for profiling programs or iterating on the PIDs of processes associated with BPF objects. In order to make it easy for users to understand what features were compiled for a given bpftool binary, print the status of the two features above when showing the version number for bpftool ("bpftool -V" or "bpftool version"). Document this in the main manual page. Example invocations: $ bpftool version ./bpftool v5.9.0-rc1 features: libbfd, skeletons $ bpftool -p version { "version": "5.9.0-rc1", "features": { "libbfd": true, "skeletons": true } } Some other parameters are optional at compilation ("DISASM_FOUR_ARGS_SIGNATURE", LIBCAP support) but they do not impact significantly bpftool's behaviour from a user's point of view, so their status is not reported. Available commands and supported program types depend on the version number, and are therefore not reported either. Note that they are already available, albeit without JSON, via bpftool's help messages. v3: - Use a simple list instead of boolean values for plain output. v2: - Fix JSON (object instead or array for the features). Signed-off-by:

Quentin Monnet <quentin@isovalent.com> Signed-off-by:

Alexei Starovoitov <ast@kernel.org> Acked-by:

Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200909162500.17010-2-quentin@isovalent.com

tools/bpf/bpftool/Documentation/bpftool.rst

+7 −1

Original line number	Diff line number	Diff line
		@@ -50,7 +50,13 @@ OPTIONS
		Print short help message (similar to bpftool help).

		-V, --version
		Print version number (similar to bpftool version).
		Print version number (similar to bpftool version), and
		optional features that were included when bpftool was
		compiled. Optional features include linking against libbfd to
		provide the disassembler for JIT-ted programs (**bpftool prog
		dump jited**) and usage of BPF skeletons (some features like
		bpftool prog profile or showing pids associated to BPF
		objects may rely on it).

		-j, --json
		Generate JSON output. For commands that cannot produce JSON, this

tools/bpf/bpftool/main.c

+31 −2

Original line number	Diff line number	Diff line
		@@ -70,13 +70,42 @@ static int do_help(int argc, char **argv)

		static int do_version(int argc, char **argv)
		{
		#ifdef HAVE_LIBBFD_SUPPORT
		const bool has_libbfd = true;
		#else
		const bool has_libbfd = false;
		#endif
		#ifdef BPFTOOL_WITHOUT_SKELETONS
		const bool has_skeletons = false;
		#else
		const bool has_skeletons = true;
		#endif

		if (json_output) {
		jsonw_start_object(json_wtr);
		jsonw_start_object(json_wtr); /* root object */

		jsonw_name(json_wtr, "version");
		jsonw_printf(json_wtr, "\"%s\"", BPFTOOL_VERSION);
		jsonw_end_object(json_wtr);

		jsonw_name(json_wtr, "features");
		jsonw_start_object(json_wtr); /* features */
		jsonw_bool_field(json_wtr, "libbfd", has_libbfd);
		jsonw_bool_field(json_wtr, "skeletons", has_skeletons);
		jsonw_end_object(json_wtr); /* features */

		jsonw_end_object(json_wtr); /* root object */
		} else {
		unsigned int nb_features = 0;

		printf("%s v%s\n", bin_name, BPFTOOL_VERSION);
		printf("features:");
		if (has_libbfd) {
		printf(" libbfd");
		nb_features++;
		}
		if (has_skeletons)
		printf("%s skeletons", nb_features++ ? "," : "");
		printf("\n");
		}
		return 0;
		}

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