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authorQuentin Monnet <quentin@isovalent.com>2020-09-09 19:24:58 +0300
committerAlexei Starovoitov <ast@kernel.org>2020-09-10 21:16:46 +0300
commit82b8cf0acc7bfe7b247e5ddc4417f6146d74c0b8 (patch)
treeaddb627b4603963a8f4bfbaac7cf19483fbede1a /tools/bpf
parent41d5c37b74084b44ccc688dbab508acb5fdddc48 (diff)
downloadlinux-82b8cf0acc7bfe7b247e5ddc4417f6146d74c0b8.tar.xz
tools: bpftool: Print optional built-in features along with version
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
Diffstat (limited to 'tools/bpf')
-rw-r--r--tools/bpf/bpftool/Documentation/bpftool.rst8
-rw-r--r--tools/bpf/bpftool/main.c33
2 files changed, 38 insertions, 3 deletions
diff --git a/tools/bpf/bpftool/Documentation/bpftool.rst b/tools/bpf/bpftool/Documentation/bpftool.rst
index 420d4d5df8b6..a3629a3f1175 100644
--- a/tools/bpf/bpftool/Documentation/bpftool.rst
+++ b/tools/bpf/bpftool/Documentation/bpftool.rst
@@ -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
diff --git a/tools/bpf/bpftool/main.c b/tools/bpf/bpftool/main.c
index 4a191fcbeb82..682daaa49e6a 100644
--- a/tools/bpf/bpftool/main.c
+++ b/tools/bpf/bpftool/main.c
@@ -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;
}