libbpf: make libbpf.map source of truth for libbpf version

Currently libbpf version is specified in 2 places: libbpf.map and
Makefile. They easily get out of sync and it's very easy to update one,
but forget to update another one. In addition, Github projection of
libbpf has to maintain its own version which has to be remembered to be
kept in sync manually, which is very error-prone approach.

This patch makes libbpf.map a source of truth for libbpf version and
uses shell invocation to parse out correct full and major libbpf version
to use during build. Now we need to make sure that once new release
cycle starts, we need to add (initially) empty section to libbpf.map
with correct latest version.

This also will make it possible to keep Github projection consistent
with kernel sources version of libbpf by adopting similar parsing of
version from libbpf.map.

v2->v3:
- grep -o + sort -rV (Andrey);

v1->v2:
- eager version vars evaluation (Jakub);
- simplified version regex (Andrey);

Cc: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile
index 9312066a1ae380b0ce9b9abb6c5923d86d047bd8..148a2716418926d8667aab8258eb1898f7ad5ffc 100644 (file)
--- a/tools/lib/bpf/Makefile
+++ b/tools/lib/bpf/Makefile
@@ -1,9 +1,10 @@
 # SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
 # Most of this file is copied from tools/lib/traceevent/Makefile
 
-BPF_VERSION = 0
-BPF_PATCHLEVEL = 0
-BPF_EXTRAVERSION = 4
+LIBBPF_VERSION := $(shell \
+       grep -oE '^LIBBPF_([0-9.]+)' libbpf.map | \
+       sort -rV | head -n1 | cut -d'_' -f2)
+LIBBPF_MAJOR_VERSION := $(firstword $(subst ., ,$(LIBBPF_VERSION)))
 
 MAKEFLAGS += --no-print-directory
 
@@ -79,15 +80,9 @@ export prefix libdir src obj
 libdir_SQ = $(subst ','\'',$(libdir))
 libdir_relative_SQ = $(subst ','\'',$(libdir_relative))
 
-VERSION                = $(BPF_VERSION)
-PATCHLEVEL     = $(BPF_PATCHLEVEL)
-EXTRAVERSION   = $(BPF_EXTRAVERSION)
-
 OBJ            = $@
 N              =
 
-LIBBPF_VERSION = $(BPF_VERSION).$(BPF_PATCHLEVEL).$(BPF_EXTRAVERSION)
-
 LIB_TARGET     = libbpf.a libbpf.so.$(LIBBPF_VERSION)
 LIB_FILE       = libbpf.a libbpf.so*
 PC_FILE                = libbpf.pc
@@ -178,10 +173,10 @@ $(BPF_IN): force elfdep bpfdep
 $(OUTPUT)libbpf.so: $(OUTPUT)libbpf.so.$(LIBBPF_VERSION)
 
 $(OUTPUT)libbpf.so.$(LIBBPF_VERSION): $(BPF_IN)
-       $(QUIET_LINK)$(CC) --shared -Wl,-soname,libbpf.so.$(VERSION) \
+       $(QUIET_LINK)$(CC) --shared -Wl,-soname,libbpf.so.$(LIBBPF_MAJOR_VERSION) \
                                    -Wl,--version-script=$(VERSION_SCRIPT) $^ -lelf -o $@
        @ln -sf $(@F) $(OUTPUT)libbpf.so
-       @ln -sf $(@F) $(OUTPUT)libbpf.so.$(VERSION)
+       @ln -sf $(@F) $(OUTPUT)libbpf.so.$(LIBBPF_MAJOR_VERSION)
 
 $(OUTPUT)libbpf.a: $(BPF_IN)
        $(QUIET_LINK)$(RM) $@; $(AR) rcs $@ $^
@@ -257,7 +252,8 @@ config-clean:
 
 clean:
        $(call QUIET_CLEAN, libbpf) $(RM) $(TARGETS) $(CXX_TEST_TARGET) \
-               *.o *~ *.a *.so *.so.$(VERSION) .*.d .*.cmd *.pc LIBBPF-CFLAGS
+               *.o *~ *.a *.so *.so.$(LIBBPF_MAJOR_VERSION) .*.d .*.cmd \
+               *.pc LIBBPF-CFLAGS
        $(call QUIET_CLEAN, core-gen) $(RM) $(OUTPUT)FEATURE-DUMP.libbpf
 
 

diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index f9d316e873d8d2d7ff37d138fdef0cbbbd425bcd..4e72df8e98ba38fa03fd8bc50de7d5f9eeebf722 100644 (file)
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -184,3 +184,6 @@ LIBBPF_0.0.4 {
                perf_buffer__new_raw;
                perf_buffer__poll;
 } LIBBPF_0.0.3;
+
+LIBBPF_0.0.5 {
+} LIBBPF_0.0.4;