From: Quentin Monnet <quentin@xxxxxxxxxxxxx> Introduce a macro LIBBPF_DEPRECATED_SINCE(major, minor, message) to prepare the deprecation of two API functions. This macro marks functions as deprecated when libbpf's version reaches the values passed as an argument. As part of this change libbpf_version.h header is added with recorded major (LIBBPF_MAJOR_VERSION) and minor (LIBBPF_MINOR_VERSION) libbpf version macros. They are now part of libbpf public API and can be relied upon by user code. libbpf_version.h is installed system-wide along other libbpf public headers. Due to this new build-time auto-generated header, in-kernel applications relying on libbpf (resolve_btfids, bpftool, bpf_preload) are updated to include libbpf's output directory as part of a list of include search paths. Better fix would be to use libbpf's make_install target to install public API headers, but that clean up is left out as a future improvement. The build changes were tested by building kernel (with KBUILD_OUTPUT and O= specified explicitly), bpftool, libbpf, selftests/bpf, and resolve_btfids builds. No problems were detected. Note that because of the constraints of the C preprocessor we have to write a few lines of macro magic for each version used to prepare deprecation (0.6 for now). Also, use LIBBPF_DEPRECATED_SINCE() to schedule deprecation of btf__get_from_id() and btf__load(), which are replaced by btf__load_from_kernel_by_id() and btf__load_into_kernel(), respectively, starting from future libbpf v0.6. This is part of libbpf 1.0 effort ([0]). [0] Closes: https://github.com/libbpf/libbpf/issues/278 Co-developed-by: Quentin Monnet <quentin@xxxxxxxxxxxxx> Signed-off-by: Quentin Monnet <quentin@xxxxxxxxxxxxx> Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx> --- v1->v2: - fix bpf_preload build by adding dependency for iterators/iterators.o on libbpf.a generation (caught by BPF CI); kernel/bpf/preload/Makefile | 7 +++++-- tools/bpf/bpftool/Makefile | 4 ++++ tools/bpf/resolve_btfids/Makefile | 4 +++- tools/lib/bpf/Makefile | 24 +++++++++++++++++------- tools/lib/bpf/btf.h | 2 ++ tools/lib/bpf/libbpf_common.h | 19 +++++++++++++++++++ 6 files changed, 50 insertions(+), 10 deletions(-) diff --git a/kernel/bpf/preload/Makefile b/kernel/bpf/preload/Makefile index 1951332dd15f..ac29d4e9a384 100644 --- a/kernel/bpf/preload/Makefile +++ b/kernel/bpf/preload/Makefile @@ -10,12 +10,15 @@ LIBBPF_OUT = $(abspath $(obj)) $(LIBBPF_A): $(Q)$(MAKE) -C $(LIBBPF_SRCS) O=$(LIBBPF_OUT)/ OUTPUT=$(LIBBPF_OUT)/ $(LIBBPF_OUT)/libbpf.a -userccflags += -I $(srctree)/tools/include/ -I $(srctree)/tools/include/uapi \ +userccflags += -I$(LIBBPF_OUT) -I $(srctree)/tools/include/ \ + -I $(srctree)/tools/include/uapi \ -I $(srctree)/tools/lib/ -Wno-unused-result userprogs := bpf_preload_umd -clean-files := $(userprogs) bpf_helper_defs.h FEATURE-DUMP.libbpf staticobjs/ feature/ +clean-files := $(userprogs) libbpf_version.h bpf_helper_defs.h FEATURE-DUMP.libbpf staticobjs/ feature/ + +$(obj)/iterators/iterators.o: $(LIBBPF_A) 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 d73232be1e99..06aa1616dabe 100644 --- a/tools/bpf/bpftool/Makefile +++ b/tools/bpf/bpftool/Makefile @@ -60,6 +60,7 @@ 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 \ @@ -137,7 +138,10 @@ endif BPFTOOL_BOOTSTRAP := $(BOOTSTRAP_OUTPUT)bpftool BOOTSTRAP_OBJS = $(addprefix $(BOOTSTRAP_OUTPUT),main.o common.o json_writer.o gen.o btf.o xlated_dumper.o btf_dumper.o disasm.o) +$(BOOTSTRAP_OBJS): $(LIBBPF_BOOTSTRAP) + OBJS = $(patsubst %.c,$(OUTPUT)%.o,$(SRCS)) $(OUTPUT)disasm.o +$(OBJS): $(LIBBPF) VMLINUX_BTF_PATHS ?= $(if $(O),$(O)/vmlinux) \ $(if $(KBUILD_OUTPUT),$(KBUILD_OUTPUT)/vmlinux) \ diff --git a/tools/bpf/resolve_btfids/Makefile b/tools/bpf/resolve_btfids/Makefile index bb9fa8de7e62..d9ef8a959ed8 100644 --- a/tools/bpf/resolve_btfids/Makefile +++ b/tools/bpf/resolve_btfids/Makefile @@ -26,6 +26,7 @@ LIBBPF_SRC := $(srctree)/tools/lib/bpf/ SUBCMD_SRC := $(srctree)/tools/lib/subcmd/ BPFOBJ := $(OUTPUT)/libbpf/libbpf.a +LIBBPF_OUT := $(abspath $(dir $(BPFOBJ)))/ SUBCMDOBJ := $(OUTPUT)/libsubcmd/libsubcmd.a BINARY := $(OUTPUT)/resolve_btfids @@ -41,11 +42,12 @@ $(SUBCMDOBJ): fixdep FORCE | $(OUTPUT)/libsubcmd $(Q)$(MAKE) -C $(SUBCMD_SRC) OUTPUT=$(abspath $(dir $@))/ $(abspath $@) $(BPFOBJ): $(wildcard $(LIBBPF_SRC)/*.[ch] $(LIBBPF_SRC)/Makefile) | $(OUTPUT)/libbpf - $(Q)$(MAKE) $(submake_extras) -C $(LIBBPF_SRC) OUTPUT=$(abspath $(dir $@))/ $(abspath $@) + $(Q)$(MAKE) $(submake_extras) -C $(LIBBPF_SRC) OUTPUT=$(LIBBPF_OUT) $(abspath $@) CFLAGS := -g \ -I$(srctree)/tools/include \ -I$(srctree)/tools/include/uapi \ + -I$(LIBBPF_OUT) \ -I$(LIBBPF_SRC) \ -I$(SUBCMD_SRC) diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile index 74c3b73a5fbe..dab21e0c7cc2 100644 --- a/tools/lib/bpf/Makefile +++ b/tools/lib/bpf/Makefile @@ -8,7 +8,8 @@ VERSION_SCRIPT := libbpf.map LIBBPF_VERSION := $(shell \ grep -oE '^LIBBPF_([0-9.]+)' $(VERSION_SCRIPT) | \ sort -rV | head -n1 | cut -d'_' -f2) -LIBBPF_MAJOR_VERSION := $(firstword $(subst ., ,$(LIBBPF_VERSION))) +LIBBPF_MAJOR_VERSION := $(word 1,$(subst ., ,$(LIBBPF_VERSION))) +LIBBPF_MINOR_VERSION := $(word 2,$(subst ., ,$(LIBBPF_VERSION))) MAKEFLAGS += --no-print-directory @@ -59,7 +60,8 @@ ifndef VERBOSE VERBOSE = 0 endif -INCLUDES = -I. -I$(srctree)/tools/include -I$(srctree)/tools/include/uapi +INCLUDES = -I$(if $(OUTPUT),$(OUTPUT),.) \ + -I$(srctree)/tools/include -I$(srctree)/tools/include/uapi export prefix libdir src obj @@ -111,7 +113,9 @@ 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) LIB_TARGET := $(addprefix $(OUTPUT),$(LIB_TARGET)) LIB_FILE := $(addprefix $(OUTPUT),$(LIB_FILE)) @@ -136,7 +140,7 @@ all: fixdep all_cmd: $(CMD_TARGETS) check -$(BPF_IN_SHARED): force $(BPF_HELPER_DEFS) +$(BPF_IN_SHARED): force $(BPF_GENERATED) @(test -f ../../include/uapi/linux/bpf.h -a -f ../../../include/uapi/linux/bpf.h && ( \ (diff -B ../../include/uapi/linux/bpf.h ../../../include/uapi/linux/bpf.h >/dev/null) || \ echo "Warning: Kernel ABI header at 'tools/include/uapi/linux/bpf.h' differs from latest version at 'include/uapi/linux/bpf.h'" >&2 )) || true @@ -154,13 +158,19 @@ $(BPF_IN_SHARED): force $(BPF_HELPER_DEFS) echo "Warning: Kernel ABI header at 'tools/include/uapi/linux/if_xdp.h' differs from latest version at 'include/uapi/linux/if_xdp.h'" >&2 )) || true $(Q)$(MAKE) $(build)=libbpf OUTPUT=$(SHARED_OBJDIR) CFLAGS="$(CFLAGS) $(SHLIB_FLAGS)" -$(BPF_IN_STATIC): force $(BPF_HELPER_DEFS) +$(BPF_IN_STATIC): force $(BPF_GENERATED) $(Q)$(MAKE) $(build)=libbpf OUTPUT=$(STATIC_OBJDIR) $(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) @@ -224,10 +234,10 @@ 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_HELPER_DEFS) bpf_tracing.h \ + bpf_helpers.h $(BPF_GENERATED) bpf_tracing.h \ bpf_endian.h bpf_core_read.h skel_internal.h -install_headers: $(BPF_HELPER_DEFS) +install_headers: $(BPF_GENERATED) $(call QUIET_INSTALL, headers) \ $(foreach hdr,$(INSTALL_HEADERS), \ $(call do_install,$(hdr),$(prefix)/include/bpf,644);) @@ -240,7 +250,7 @@ install: install_lib install_pkgconfig install_headers clean: $(call QUIET_CLEAN, libbpf) $(RM) -rf $(CMD_TARGETS) \ - *~ .*.d .*.cmd LIBBPF-CFLAGS $(BPF_HELPER_DEFS) \ + *~ .*.d .*.cmd LIBBPF-CFLAGS $(BPF_GENERATED) \ $(SHARED_OBJDIR) $(STATIC_OBJDIR) \ $(addprefix $(OUTPUT), \ *.o *.a *.so *.so.$(LIBBPF_MAJOR_VERSION) *.pc) diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h index 4a711f990904..f2e2fab950b7 100644 --- a/tools/lib/bpf/btf.h +++ b/tools/lib/bpf/btf.h @@ -50,9 +50,11 @@ LIBBPF_API struct btf *libbpf_find_kernel_btf(void); LIBBPF_API struct btf *btf__load_from_kernel_by_id(__u32 id); LIBBPF_API struct btf *btf__load_from_kernel_by_id_split(__u32 id, struct btf *base_btf); +LIBBPF_DEPRECATED_SINCE(0, 6, "use btf__load_from_kernel_by_id instead") LIBBPF_API int btf__get_from_id(__u32 id, struct btf **btf); LIBBPF_API int btf__finalize_data(struct bpf_object *obj, struct btf *btf); +LIBBPF_DEPRECATED_SINCE(0, 6, "use btf__load_into_kernel instead") LIBBPF_API int btf__load(struct btf *btf); LIBBPF_API int btf__load_into_kernel(struct btf *btf); LIBBPF_API __s32 btf__find_by_name(const struct btf *btf, diff --git a/tools/lib/bpf/libbpf_common.h b/tools/lib/bpf/libbpf_common.h index 947d8bd8a7bb..36ac77f2bea2 100644 --- a/tools/lib/bpf/libbpf_common.h +++ b/tools/lib/bpf/libbpf_common.h @@ -10,6 +10,7 @@ #define __LIBBPF_LIBBPF_COMMON_H #include <string.h> +#include "libbpf_version.h" #ifndef LIBBPF_API #define LIBBPF_API __attribute__((visibility("default"))) @@ -17,6 +18,24 @@ #define LIBBPF_DEPRECATED(msg) __attribute__((deprecated(msg))) +/* Mark a symbol as deprecated when libbpf version is >= {major}.{minor} */ +#define LIBBPF_DEPRECATED_SINCE(major, minor, msg) \ + __LIBBPF_MARK_DEPRECATED_ ## major ## _ ## minor \ + (LIBBPF_DEPRECATED("libbpf v" # major "." # minor "+: " msg)) + +#define __LIBBPF_CURRENT_VERSION_GEQ(major, minor) \ + (LIBBPF_MAJOR_VERSION > (major) || \ + (LIBBPF_MAJOR_VERSION == (major) && LIBBPF_MINOR_VERSION >= (minor))) + +/* Add checks for other versions below when planning deprecation of API symbols + * with the LIBBPF_DEPRECATED_SINCE macro. + */ +#if __LIBBPF_CURRENT_VERSION_GEQ(0, 6) +#define __LIBBPF_MARK_DEPRECATED_0_6(X) X +#else +#define __LIBBPF_MARK_DEPRECATED_0_6(X) +#endif + /* Helper macro to declare and initialize libbpf options struct * * This dance with uninitialized declaration, followed by memset to zero, -- 2.30.2
