From: Quentin Monnet <quentin@isovalent.com>
Date: Thu, 10 Feb 2022 10:42:36 +0000
Subject: bpftool: Add libbpf's version number to "bpftool version" output
Patch-mainline: v5.18-rc1
Git-commit: 61fce9693f0311949c59cc62a8fdee6e36243553
References: jsc#PED-1377

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
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
---
 tools/bpf/bpftool/Documentation/common_options.rst |   13 +++++++------
 tools/bpf/bpftool/main.c                           |    4 ++++
 2 files changed, 11 insertions(+), 6 deletions(-)

--- 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
--- a/tools/bpf/bpftool/main.c
+++ b/tools/bpf/bpftool/main.c
@@ -89,6 +89,9 @@ static int do_version(int argc, char **a
 
 		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 **a
 		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");