From e41ac2020bca4acdb7485ddca34098f68d3af5ae Mon Sep 17 00:00:00 2001 From: Quentin Monnet Date: Fri, 5 Nov 2021 01:58:13 +0000 Subject: [PATCH] bpftool: Install libbpf headers for the bootstrap version, too We recently changed bpftool's Makefile to make it install libbpf's headers locally instead of pulling them from the source directory of the library. Although bpftool needs two versions of libbpf, a "regular" one and a "bootstrap" version, we would only install headers for the regular libbpf build. Given that this build always occurs before the bootstrap build when building bpftool, this is enough to ensure that the bootstrap bpftool will have access to the headers exported through the regular libbpf build. However, this did not account for the case when we only want the bootstrap version of bpftool, through the "bootstrap" target. For example, perf needs the bootstrap version only, to generate BPF skeletons. In that case, when are the headers installed? For some time, the issue has been masked, because we had a step (the installation of headers internal to libbpf) which would depend on the regular build of libbpf and hence trigger the export of the headers, just for the sake of creating a directory. But this changed with commit 8b6c46241c77 ("bpftool: Remove Makefile dep. on $(LIBBPF) for $(LIBBPF_INTERNAL_HDRS)"), where we cleaned up that stage and removed the dependency on the regular libbpf build. As a result, when we only want the bootstrap bpftool version, the regular libbpf is no longer built. The bootstrap libbpf version is built, but headers are not exported, and the bootstrap bpftool build fails because of the missing headers. To fix this, we also install the library headers for the bootstrap version of libbpf, to use them for the bootstrap bpftool and for generating the skeletons. Fixes: f012ade10b34 ("bpftool: Install libbpf headers instead of including the dir") Reported-by: Arnaldo Carvalho de Melo Signed-off-by: Quentin Monnet Signed-off-by: Daniel Borkmann Tested-by: Arnaldo Carvalho de Melo Link: https://lore.kernel.org/bpf/20211105015813.6171-1-quentin@isovalent.com --- tools/bpf/bpftool/Makefile | 32 ++++++++++++++++++++++---------- 1 file changed, 22 insertions(+), 10 deletions(-) diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile index c0c30e5..7cfba11 100644 --- a/tools/bpf/bpftool/Makefile +++ b/tools/bpf/bpftool/Makefile @@ -22,24 +22,29 @@ else _OUTPUT := $(CURDIR) endif BOOTSTRAP_OUTPUT := $(_OUTPUT)/bootstrap/ + LIBBPF_OUTPUT := $(_OUTPUT)/libbpf/ LIBBPF_DESTDIR := $(LIBBPF_OUTPUT) LIBBPF_INCLUDE := $(LIBBPF_DESTDIR)/include LIBBPF_HDRS_DIR := $(LIBBPF_INCLUDE)/bpf +LIBBPF := $(LIBBPF_OUTPUT)libbpf.a -LIBBPF = $(LIBBPF_OUTPUT)libbpf.a -LIBBPF_BOOTSTRAP_OUTPUT = $(BOOTSTRAP_OUTPUT)libbpf/ -LIBBPF_BOOTSTRAP = $(LIBBPF_BOOTSTRAP_OUTPUT)libbpf.a +LIBBPF_BOOTSTRAP_OUTPUT := $(BOOTSTRAP_OUTPUT)libbpf/ +LIBBPF_BOOTSTRAP_DESTDIR := $(LIBBPF_BOOTSTRAP_OUTPUT) +LIBBPF_BOOTSTRAP_INCLUDE := $(LIBBPF_BOOTSTRAP_DESTDIR)/include +LIBBPF_BOOTSTRAP_HDRS_DIR := $(LIBBPF_BOOTSTRAP_INCLUDE)/bpf +LIBBPF_BOOTSTRAP := $(LIBBPF_BOOTSTRAP_OUTPUT)libbpf.a # We need to copy hashmap.h and nlattr.h which is not otherwise exported by # libbpf, but still required by bpftool. LIBBPF_INTERNAL_HDRS := $(addprefix $(LIBBPF_HDRS_DIR)/,hashmap.h nlattr.h) +LIBBPF_BOOTSTRAP_INTERNAL_HDRS := $(addprefix $(LIBBPF_BOOTSTRAP_HDRS_DIR)/,hashmap.h) ifeq ($(BPFTOOL_VERSION),) BPFTOOL_VERSION := $(shell make -rR --no-print-directory -sC ../../.. kernelversion) endif -$(LIBBPF_OUTPUT) $(BOOTSTRAP_OUTPUT) $(LIBBPF_BOOTSTRAP_OUTPUT) $(LIBBPF_HDRS_DIR): +$(LIBBPF_OUTPUT) $(BOOTSTRAP_OUTPUT) $(LIBBPF_BOOTSTRAP_OUTPUT) $(LIBBPF_HDRS_DIR) $(LIBBPF_BOOTSTRAP_HDRS_DIR): $(QUIET_MKDIR)mkdir -p $@ $(LIBBPF): $(wildcard $(BPF_DIR)/*.[ch] $(BPF_DIR)/Makefile) | $(LIBBPF_OUTPUT) @@ -52,7 +57,12 @@ $(LIBBPF_INTERNAL_HDRS): $(LIBBPF_HDRS_DIR)/%.h: $(BPF_DIR)/%.h | $(LIBBPF_HDRS_ $(LIBBPF_BOOTSTRAP): $(wildcard $(BPF_DIR)/*.[ch] $(BPF_DIR)/Makefile) | $(LIBBPF_BOOTSTRAP_OUTPUT) $(Q)$(MAKE) -C $(BPF_DIR) OUTPUT=$(LIBBPF_BOOTSTRAP_OUTPUT) \ - ARCH= CC=$(HOSTCC) LD=$(HOSTLD) $@ + DESTDIR=$(LIBBPF_BOOTSTRAP_DESTDIR) prefix= \ + ARCH= CC=$(HOSTCC) LD=$(HOSTLD) $@ install_headers + +$(LIBBPF_BOOTSTRAP_INTERNAL_HDRS): $(LIBBPF_BOOTSTRAP_HDRS_DIR)/%.h: $(BPF_DIR)/%.h | $(LIBBPF_BOOTSTRAP_HDRS_DIR) + $(call QUIET_INSTALL, $@) + $(Q)install -m 644 -t $(LIBBPF_BOOTSTRAP_HDRS_DIR) $< $(LIBBPF)-clean: FORCE | $(LIBBPF_OUTPUT) $(call QUIET_CLEAN, libbpf) @@ -172,11 +182,11 @@ else $(Q)cp "$(VMLINUX_H)" $@ endif -$(OUTPUT)%.bpf.o: skeleton/%.bpf.c $(OUTPUT)vmlinux.h $(LIBBPF) +$(OUTPUT)%.bpf.o: skeleton/%.bpf.c $(OUTPUT)vmlinux.h $(LIBBPF_BOOTSTRAP) $(QUIET_CLANG)$(CLANG) \ -I$(if $(OUTPUT),$(OUTPUT),.) \ -I$(srctree)/tools/include/uapi/ \ - -I$(LIBBPF_INCLUDE) \ + -I$(LIBBPF_BOOTSTRAP_INCLUDE) \ -g -O2 -Wall -target bpf -c $< -o $@ && $(LLVM_STRIP) -g $@ $(OUTPUT)%.skel.h: $(OUTPUT)%.bpf.o $(BPFTOOL_BOOTSTRAP) @@ -209,8 +219,10 @@ $(BPFTOOL_BOOTSTRAP): $(BOOTSTRAP_OBJS) $(LIBBPF_BOOTSTRAP) $(OUTPUT)bpftool: $(OBJS) $(LIBBPF) $(QUIET_LINK)$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $(OBJS) $(LIBS) -$(BOOTSTRAP_OUTPUT)%.o: %.c $(LIBBPF_INTERNAL_HDRS) | $(BOOTSTRAP_OUTPUT) - $(QUIET_CC)$(HOSTCC) $(CFLAGS) -c -MMD -o $@ $< +$(BOOTSTRAP_OUTPUT)%.o: %.c $(LIBBPF_BOOTSTRAP_INTERNAL_HDRS) | $(BOOTSTRAP_OUTPUT) + $(QUIET_CC)$(HOSTCC) \ + $(subst -I$(LIBBPF_INCLUDE),-I$(LIBBPF_BOOTSTRAP_INCLUDE),$(CFLAGS)) \ + -c -MMD -o $@ $< $(OUTPUT)%.o: %.c $(QUIET_CC)$(CC) $(CFLAGS) -c -MMD -o $@ $< @@ -257,6 +269,6 @@ doc-uninstall: FORCE: .SECONDARY: -.PHONY: all FORCE clean install-bin install uninstall +.PHONY: all FORCE bootstrap clean install-bin install uninstall .PHONY: doc doc-clean doc-install doc-uninstall .DEFAULT_GOAL := all -- 2.7.4