bpftool: Allow to link libbpf with libbpf package
Currently we support only static linking with kernel's libbpf
(tools/lib/bpf). This patch adds LIBBPF_DYNAMIC compile variable
that triggers libbpf detection and bpf dynamic linking:
$ make -C tools/bpf/bpftool make LIBBPF_DYNAMIC=1
If libbpf is not installed, build (with LIBBPF_DYNAMIC=1) stops with:
$ make -C tools/bpf/bpftool LIBBPF_DYNAMIC=1
Auto-detecting system features:
... libbfd: [ on ]
... disassembler-four-args: [ on ]
... zlib: [ on ]
... libbpf: [ OFF ]
Makefile:102: *** Error: No libbpf devel library found, please install libbpf-devel or libbpf-dev.
Adding LIBBPF_DIR compile variable to allow linking with
libbpf installed into specific directory:
$ make -C tools/lib/bpf/ prefix=/tmp/libbpf/ install_lib install_headers
$ make -C tools/bpf/bpftool/ LIBBPF_DYNAMIC=1 LIBBPF_DIR=/tmp/libbpf/
It might be needed to clean build tree first because features
framework does not detect the change properly:
$ make -C tools/build/feature clean
$ make -C tools/bpf/bpftool/ clean
Since bpftool uses bits of libbpf that are not exported as public API in
the .so version, we also pass in libbpf.a to the linker, which allows it to
pick up the private functions from the static library without having to
expose them as ABI.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
1 file changed
