libbpf: add libelf dependency to shared library build

Björn Töpel · borkmann · commit 89dedaef49d3 · 2019-03-28T16:24:52.000+01:00
The DPDK project is moving forward with its AF_XDP PMD, and during that process some libbpf issues surfaced [1]: When libbpf was built as a shared library, libelf was not included in the linking phase. Since libelf is an internal depedency to libbpf, libelf should be included. This patch adds '-lelf' to resolve that. [1] https://patches.dpdk.org/patch/50704/#93571 Fixes: 1b76c13 ("bpf tools: Introduce 'bpf' library and add bpf feature check") Suggested-by: Luca Boccassi <bluca@debian.org> Signed-off-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile
@@ -177,7 +177,7 @@ $(OUTPUT)libbpf.so: $(OUTPUT)libbpf.so.$(LIBBPF_VERSION)
 
 $(OUTPUT)libbpf.so.$(LIBBPF_VERSION): $(BPF_IN)
 	$(QUIET_LINK)$(CC) --shared -Wl,-soname,libbpf.so.$(VERSION) \
-				    -Wl,--version-script=$(VERSION_SCRIPT) $^ -o $@
+				    -Wl,--version-script=$(VERSION_SCRIPT) $^ -lelf -o $@
 	@ln -sf $(@F) $(OUTPUT)libbpf.so
 	@ln -sf $(@F) $(OUTPUT)libbpf.so.$(VERSION)
 
