libbpf: Re-build libbpf.so when libbpf.map changes

Ensure libbpf.so is re-built whenever libbpf.map is modified.  Without this,
changes to libbpf.map are not detected and versioned symbols mismatch error
will be reported until `make clean && make` is used, which is a suboptimal
developer experience.

Fixes: 306b267cb3 ("libbpf: Verify versioned symbols")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210815070609.987780-8-andrii@kernel.org
This commit is contained in:
Andrii Nakryiko 2021-08-15 00:06:00 -07:00 committed by Daniel Borkmann
parent 7adfc6c9b3
commit 61c7aa5020

View file

@ -4,8 +4,9 @@
RM ?= rm
srctree = $(abs_srctree)
VERSION_SCRIPT := libbpf.map
LIBBPF_VERSION := $(shell \
grep -oE '^LIBBPF_([0-9.]+)' libbpf.map | \
grep -oE '^LIBBPF_([0-9.]+)' $(VERSION_SCRIPT) | \
sort -rV | head -n1 | cut -d'_' -f2)
LIBBPF_MAJOR_VERSION := $(firstword $(subst ., ,$(LIBBPF_VERSION)))
@ -110,7 +111,6 @@ SHARED_OBJDIR := $(OUTPUT)sharedobjs/
STATIC_OBJDIR := $(OUTPUT)staticobjs/
BPF_IN_SHARED := $(SHARED_OBJDIR)libbpf-in.o
BPF_IN_STATIC := $(STATIC_OBJDIR)libbpf-in.o
VERSION_SCRIPT := libbpf.map
BPF_HELPER_DEFS := $(OUTPUT)bpf_helper_defs.h
LIB_TARGET := $(addprefix $(OUTPUT),$(LIB_TARGET))
@ -163,10 +163,10 @@ $(BPF_HELPER_DEFS): $(srctree)/tools/include/uapi/linux/bpf.h
$(OUTPUT)libbpf.so: $(OUTPUT)libbpf.so.$(LIBBPF_VERSION)
$(OUTPUT)libbpf.so.$(LIBBPF_VERSION): $(BPF_IN_SHARED)
$(OUTPUT)libbpf.so.$(LIBBPF_VERSION): $(BPF_IN_SHARED) $(VERSION_SCRIPT)
$(QUIET_LINK)$(CC) $(LDFLAGS) \
--shared -Wl,-soname,libbpf.so.$(LIBBPF_MAJOR_VERSION) \
-Wl,--version-script=$(VERSION_SCRIPT) $^ -lelf -lz -o $@
-Wl,--version-script=$(VERSION_SCRIPT) $< -lelf -lz -o $@
@ln -sf $(@F) $(OUTPUT)libbpf.so
@ln -sf $(@F) $(OUTPUT)libbpf.so.$(LIBBPF_MAJOR_VERSION)
@ -181,7 +181,7 @@ $(OUTPUT)libbpf.pc:
check: check_abi
check_abi: $(OUTPUT)libbpf.so
check_abi: $(OUTPUT)libbpf.so $(VERSION_SCRIPT)
@if [ "$(GLOBAL_SYM_COUNT)" != "$(VERSIONED_SYM_COUNT)" ]; then \
echo "Warning: Num of global symbols in $(BPF_IN_SHARED)" \
"($(GLOBAL_SYM_COUNT)) does NOT match with num of" \