2022-02-01 22:59 UTC-0800 ~ Andrii Nakryiko [off-list ref]

On Mon, Jan 31, 2022 at 1:11 PM Quentin Monnet [off-list ref] wrote:

quoted

To help users check what version of libbpf has been used to compile
bpftool, embed the version number and print it along with bpftool's own
version number.

Signed-off-by: Quentin Monnet <redacted>
---
 tools/bpf/bpftool/Documentation/common_options.rst | 3 ++-
 tools/bpf/bpftool/Makefile                         | 2 ++
 tools/bpf/bpftool/main.c                           | 3 +++
 3 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/tools/bpf/bpftool/Documentation/common_options.rst b/tools/bpf/bpftool/Documentation/common_options.rst
index 908487b9c2ad..24166733d3ae 100644
--- a/tools/bpf/bpftool/Documentation/common_options.rst
+++ b/tools/bpf/bpftool/Documentation/common_options.rst

@@ -4,7 +4,8 @@
          Print short help message (similar to **bpftool help**).

 -V, --version
-         Print version number (similar to **bpftool version**), and optional
+         Print bpftool's version number (similar to **bpftool version**), the
+         version of libbpf that was used to compile the binary, 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

diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile
index 83369f55df61..bd5a8cafac49 100644
--- a/tools/bpf/bpftool/Makefile
+++ b/tools/bpf/bpftool/Makefile

@@ -42,6 +42,7 @@ LIBBPF_BOOTSTRAP_INTERNAL_HDRS := $(addprefix $(LIBBPF_BOOTSTRAP_HDRS_DIR)/,hash
 ifeq ($(BPFTOOL_VERSION),)
 BPFTOOL_VERSION := $(shell make -rR --no-print-directory -sC ../../.. kernelversion)
 endif
+LIBBPF_VERSION := $(shell make -r --no-print-directory -sC $(BPF_DIR) libbpfversion)

why can't you use libbpf_version_string() API instead?

I missed it somehow, thanks for the pointer. It seems to be a recent
addition to libbpf, and it was probably not present last time I checked
for such an API. I'll use it.