libbpf: Make libbpf_version.h non-auto-generated

Turn previously auto-generated libbpf_version.h header into a normal
header file. This prevents various tricky Makefile integration issues,
simplifies the overall build process, but also allows to further extend
it with some more versioning-related APIs in the future.

To prevent accidental out-of-sync versions as defined by libbpf.map and
libbpf_version.h, Makefile checks their consistency at build time.

Simultaneously with this change bump libbpf.map to v0.6.

Also undo adding libbpf's output directory into include path for
kernel/bpf/preload, bpftool, and resolve_btfids, which is not necessary
because libbpf_version.h is just a normal header like any other.

Fixes: 0b46b7550560 ("libbpf: Add LIBBPF_DEPRECATED_SINCE macro for scheduling API deprecations")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210913222309.3220849-1-andrii@kernel.org

diff --git a/kernel/bpf/preload/Makefile b/kernel/bpf/preload/Makefile
index ac29d4e..1951332 100644 (file)
--- a/kernel/bpf/preload/Makefile
+++ b/kernel/bpf/preload/Makefile
@@ -10,15 +10,12 @@ LIBBPF_OUT = $(abspath $(obj))
 $(LIBBPF_A):
        $(Q)$(MAKE) -C $(LIBBPF_SRCS) O=$(LIBBPF_OUT)/ OUTPUT=$(LIBBPF_OUT)/ $(LIBBPF_OUT)/libbpf.a
 
-userccflags += -I$(LIBBPF_OUT) -I $(srctree)/tools/include/ \
-       -I $(srctree)/tools/include/uapi \
+userccflags += -I $(srctree)/tools/include/ -I $(srctree)/tools/include/uapi \
        -I $(srctree)/tools/lib/ -Wno-unused-result
 
 userprogs := bpf_preload_umd
 
-clean-files := $(userprogs) libbpf_version.h bpf_helper_defs.h FEATURE-DUMP.libbpf staticobjs/ feature/
-
-$(obj)/iterators/iterators.o: $(LIBBPF_A)
+clean-files := $(userprogs) bpf_helper_defs.h FEATURE-DUMP.libbpf staticobjs/ feature/
 
 bpf_preload_umd-objs := iterators/iterators.o
 bpf_preload_umd-userldlibs := $(LIBBPF_A) -lelf -lz

diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile
index 06aa161..1fcf5b0 100644 (file)
--- a/tools/bpf/bpftool/Makefile
+++ b/tools/bpf/bpftool/Makefile
@@ -60,7 +60,6 @@ CFLAGS += -W -Wall -Wextra -Wno-unused-parameter -Wno-missing-field-initializers
 CFLAGS += $(filter-out -Wswitch-enum -Wnested-externs,$(EXTRA_WARNINGS))
 CFLAGS += -DPACKAGE='"bpftool"' -D__EXPORTED_HEADERS__ \
        -I$(if $(OUTPUT),$(OUTPUT),.) \
-       $(if $(LIBBPF_OUTPUT),-I$(LIBBPF_OUTPUT)) \
        -I$(srctree)/kernel/bpf/ \
        -I$(srctree)/tools/include \
        -I$(srctree)/tools/include/uapi \

diff --git a/tools/bpf/resolve_btfids/Makefile b/tools/bpf/resolve_btfids/Makefile
index edc0c32..08b75e3 100644 (file)
--- a/tools/bpf/resolve_btfids/Makefile
+++ b/tools/bpf/resolve_btfids/Makefile
@@ -47,7 +47,6 @@ $(BPFOBJ): $(wildcard $(LIBBPF_SRC)/*.[ch] $(LIBBPF_SRC)/Makefile) | $(OUTPUT)/l
 CFLAGS := -g \
           -I$(srctree)/tools/include \
           -I$(srctree)/tools/include/uapi \
-          -I$(LIBBPF_OUT) \
           -I$(LIBBPF_SRC) \
           -I$(SUBCMD_SRC)
 

diff --git a/tools/lib/bpf/.gitignore b/tools/lib/bpf/.gitignore
index 5d4cfac..0da84cb 100644 (file)
--- a/tools/lib/bpf/.gitignore
+++ b/tools/lib/bpf/.gitignore
@@ -1,5 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0-only
-libbpf_version.h
 libbpf.pc
 libbpf.so.*
 TAGS

diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile
index dab21e0..0f76634 100644 (file)
--- a/tools/lib/bpf/Makefile
+++ b/tools/lib/bpf/Makefile
@@ -113,9 +113,8 @@ 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_HDR    := $(OUTPUT)libbpf_version.h
 BPF_HELPER_DEFS        := $(OUTPUT)bpf_helper_defs.h
-BPF_GENERATED  := $(BPF_HELPER_DEFS) $(VERSION_HDR)
+BPF_GENERATED  := $(BPF_HELPER_DEFS)
 
 LIB_TARGET     := $(addprefix $(OUTPUT),$(LIB_TARGET))
 LIB_FILE       := $(addprefix $(OUTPUT),$(LIB_FILE))
@@ -165,12 +164,6 @@ $(BPF_HELPER_DEFS): $(srctree)/tools/include/uapi/linux/bpf.h
        $(QUIET_GEN)$(srctree)/scripts/bpf_doc.py --header \
                --file $(srctree)/tools/include/uapi/linux/bpf.h > $(BPF_HELPER_DEFS)
 
-$(VERSION_HDR): force
-       $(QUIET_GEN)echo "/* This file was auto-generated. */" > $@
-       @echo "" >> $@
-       @echo "#define LIBBPF_MAJOR_VERSION $(LIBBPF_MAJOR_VERSION)" >> $@
-       @echo "#define LIBBPF_MINOR_VERSION $(LIBBPF_MINOR_VERSION)" >> $@
-
 $(OUTPUT)libbpf.so: $(OUTPUT)libbpf.so.$(LIBBPF_VERSION)
 
 $(OUTPUT)libbpf.so.$(LIBBPF_VERSION): $(BPF_IN_SHARED) $(VERSION_SCRIPT)
@@ -189,7 +182,7 @@ $(OUTPUT)libbpf.pc:
                -e "s|@VERSION@|$(LIBBPF_VERSION)|" \
                < libbpf.pc.template > $@
 
-check: check_abi
+check: check_abi check_version
 
 check_abi: $(OUTPUT)libbpf.so $(VERSION_SCRIPT)
        @if [ "$(GLOBAL_SYM_COUNT)" != "$(VERSIONED_SYM_COUNT)" ]; then  \
@@ -215,6 +208,21 @@ check_abi: $(OUTPUT)libbpf.so $(VERSION_SCRIPT)
                exit 1;                                                  \
        fi
 
+HDR_MAJ_VERSION := $(shell grep -oE '^\#define LIBBPF_MAJOR_VERSION ([0-9]+)$$' libbpf_version.h | cut -d' ' -f3)
+HDR_MIN_VERSION := $(shell grep -oE '^\#define LIBBPF_MINOR_VERSION ([0-9]+)$$' libbpf_version.h | cut -d' ' -f3)
+
+check_version: $(VERSION_SCRIPT) libbpf_version.h
+       @if [ "$(HDR_MAJ_VERSION)" != "$(LIBBPF_MAJOR_VERSION)" ]; then        \
+               echo "Error: libbpf major version mismatch detected: "         \
+                    "'$(HDR_MAJ_VERSION)' != '$(LIBBPF_MAJOR_VERSION)'" >&2;  \
+               exit 1;                                                        \
+       fi
+       @if [ "$(HDR_MIN_VERSION)" != "$(LIBBPF_MINOR_VERSION)" ]; then        \
+               echo "Error: libbpf minor version mismatch detected: "         \
+                    "'$(HDR_MIN_VERSION)' != '$(LIBBPF_MINOR_VERSION)'" >&2;  \
+               exit 1;                                                        \
+       fi
+
 define do_install_mkdir
        if [ ! -d '$(DESTDIR_SQ)$1' ]; then             \
                $(INSTALL) -d -m 755 '$(DESTDIR_SQ)$1'; \
@@ -234,8 +242,9 @@ install_lib: all_cmd
                cp -fpR $(LIB_FILE) $(DESTDIR)$(libdir_SQ)
 
 INSTALL_HEADERS = bpf.h libbpf.h btf.h libbpf_common.h libbpf_legacy.h xsk.h \
-                 bpf_helpers.h $(BPF_GENERATED) bpf_tracing.h       \
-                 bpf_endian.h bpf_core_read.h skel_internal.h
+                 bpf_helpers.h $(BPF_GENERATED) bpf_tracing.h               \
+                 bpf_endian.h bpf_core_read.h skel_internal.h               \
+                 libbpf_version.h
 
 install_headers: $(BPF_GENERATED)
        $(call QUIET_INSTALL, headers)                                       \
@@ -255,7 +264,7 @@ clean:
                $(addprefix $(OUTPUT),                                       \
                            *.o *.a *.so *.so.$(LIBBPF_MAJOR_VERSION) *.pc)
 
-PHONY += force cscope tags
+PHONY += force cscope tags check check_abi check_version
 force:
 
 cscope:

diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index bbc53bb..78ea62c 100644 (file)
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -386,3 +386,6 @@ LIBBPF_0.5.0 {
                btf_dump__dump_type_data;
                libbpf_set_strict_mode;
 } LIBBPF_0.4.0;
+
+LIBBPF_0.6.0 {
+} LIBBPF_0.5.0;

diff --git a/tools/lib/bpf/libbpf_version.h b/tools/lib/bpf/libbpf_version.h
new file mode 100644 (file)
index 0000000..dd56d76
--- /dev/null
+++ b/tools/lib/bpf/libbpf_version.h
@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
+/* Copyright (C) 2021 Facebook */
+#ifndef __LIBBPF_VERSION_H
+#define __LIBBPF_VERSION_H
+
+#define LIBBPF_MAJOR_VERSION 0
+#define LIBBPF_MINOR_VERSION 6
+
+#endif /* __LIBBPF_VERSION_H */