bpftool: Add libbpf's version number to "bpftool version" output

To help users check what version of libbpf is being used with bpftool,
print the number along with bpftool's own version number.

Output:

    $ ./bpftool version
    ./bpftool v5.16.0
    using libbpf v0.7
    features: libbfd, libbpf_strict, skeletons

    $ ./bpftool version --json --pretty
    {
        "version": "5.16.0",
        "libbpf_version": "0.7",
        "features": {
            "libbfd": true,
            "libbpf_strict": true,
            "skeletons": true
        }
    }

Note that libbpf does not expose its patch number.

Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220210104237.11649-2-quentin@isovalent.com

diff --git a/tools/bpf/bpftool/Documentation/common_options.rst b/tools/bpf/bpftool/Documentation/common_options.rst
index 908487b9c2adfd2f9c8470ffbfb3c3a76c29a3b3..4107a586b68b946ef825c8013219d3e6c5ef2087 100644 (file)
--- a/tools/bpf/bpftool/Documentation/common_options.rst
+++ b/tools/bpf/bpftool/Documentation/common_options.rst
@@ -4,12 +4,13 @@
          Print short help message (similar to **bpftool help**).
 
 -V, --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).
+         Print bpftool's version number (similar to **bpftool version**), the
+         number of the libbpf version in use, 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 490f7bd54e4c272637b31acbe746222744660a04..0f2f8de514a495a1f31f91578ad2d1e221e776f4 100644 (file)
--- a/tools/bpf/bpftool/main.c
+++ b/tools/bpf/bpftool/main.c
@@ -89,6 +89,9 @@ static int do_version(int argc, char **argv)
 
                jsonw_name(json_wtr, "version");
                jsonw_printf(json_wtr, "\"%s\"", BPFTOOL_VERSION);
+               jsonw_name(json_wtr, "libbpf_version");
+               jsonw_printf(json_wtr, "\"%d.%d\"",
+                            libbpf_major_version(), libbpf_minor_version());
 
                jsonw_name(json_wtr, "features");
                jsonw_start_object(json_wtr);   /* features */
@@ -102,6 +105,7 @@ static int do_version(int argc, char **argv)
                unsigned int nb_features = 0;
 
                printf("%s v%s\n", bin_name, BPFTOOL_VERSION);
+               printf("using libbpf %s\n", libbpf_version_string());
                printf("features:");
                if (has_libbfd) {
                        printf(" libbfd");