执行make编译XDP教程basic01时出现No rule to make target错误求助

问题描述 #

执行make编译basic01-xdp-pass时出现以下错误：

make[1]: *** No rule to make target 'all'. Stop.
make: *** [../common/common.mk:94: ../lib/install/lib/libxdp.a] Error 2

涉及的文件内容如下：

Makefile #

# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)

XDP_TARGETS := xdp_pass_kern  
USER_TARGETS := xdp_pass_user

LLC ?= llc
CLANG ?= clang
CC := gcc

COMMON_DIR = ../common
COMMON_OBJS += $(COMMON_DIR)/common_user_bpf_xdp.o

include $(COMMON_DIR)/common.mk

xdp_pass_kern.c #

/* SPDX-License-Identifier: GPL-2.0 */
#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>

SEC("xdp")
int  xdp_prog_simple(struct xdp_md *ctx)
{
    return XDP_PASS;
}

char _license[] SEC("license") = "GPL";

common.mk #

# Common Makefile parts for BPF-building with libbpf
# --------------------------------------------------
# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
#
# This file should be included from your Makefile like:
#  COMMON_DIR = ../common
#  include $(COMMON_DIR)/common.mk
#
# It is expected that you define the variables:
#  XDP_TARGETS and USER_TARGETS
# as a space-separated list
#
LLC ?= llc
CLANG ?= clang
CC ?= gcc

XDP_C = ${XDP_TARGETS:=.c}
XDP_OBJ = ${XDP_C:.c=.o}
USER_C := ${USER_TARGETS:=.c}
USER_OBJ := ${USER_C:.c=.o}

# Expect this is defined by including Makefile, but define if not
COMMON_DIR ?= ../common
LIB_DIR ?= ../lib

COPY_LOADER ?=
LOADER_DIR ?= $(LIB_DIR)/xdp-tools/xdp-loader
STATS_DIR ?= $(COMMON_DIR)/../basic-solutions

COMMON_OBJS += $(COMMON_DIR)/common_params.o
include $(LIB_DIR)/defines.mk

# Create expansions for dependencies
COMMON_H := ${COMMON_OBJS:.o=.h}

EXTRA_DEPS +=

# BPF-prog kern and userspace shares struct via header file:
KERN_USER_H ?= $(wildcard common_kern_user.h)

CFLAGS += -I$(LIB_DIR)/install/include $(EXTRA_CFLAGS)
BPF_CFLAGS += -I$(LIB_DIR)/install/include $(EXTRA_CFLAGS)
LDFLAGS += -L$(LIB_DIR)/install/lib

BPF_HEADERS := $(wildcard $(HEADER_DIR)/*/*.h) $(wildcard $(INCLUDE_DIR)/*/*.h)

all: llvm-check $(USER_TARGETS) $(XDP_OBJ) $(COPY_LOADER) $(COPY_STATS)

.PHONY: clean $(CLANG) $(LLC)

clean:
    $(Q)rm -f $(USER_TARGETS) $(XDP_OBJ) $(USER_OBJ) $(COPY_LOADER) $(COPY_STATS) *.ll

ifdef COPY_LOADER
$(LOADER_DIR)/$(COPY_LOADER):
    $(Q)make -C $(LOADER_DIR)

$(COPY_LOADER): $(LOADER_DIR)/$(COPY_LOADER)
    $(QUIET_COPY)cp $(LOADER_DIR)/$(COPY_LOADER) $(COPY_LOADER)
endif

ifdef COPY_STATS
$(STATS_DIR)/$(COPY_STATS): $(STATS_DIR)/${COPY_STATS:=.c} $(COMMON_H)
    $(Q)$(MAKE) -C $(STATS_DIR) $(COPY_STATS)

$(COPY_STATS):  $(STATS_DIR)/$(COPY_STATS)
    $(QUIET_COPY)cp $(STATS_DIR)/$(COPY_STATS) $(COPY_STATS)
# Needing xdp_stats imply depending on header files:
EXTRA_DEPS += $(COMMON_DIR)/xdp_stats_kern.h $(COMMON_DIR)/xdp_stats_kern_user.h
endif

# For build dependency on this file, if it gets updated
COMMON_MK = $(COMMON_DIR)/common.mk

llvm-check: $(CLANG) $(LLC)
    @for TOOL in $^ ; do \
        if [ ! $$(command -v $${TOOL} 2>/dev/null) ]; then \
            echo "*** ERROR: Cannot find tool $${TOOL}" ;\
            exit 1; \
        else true; fi; \
    done

$(OBJECT_LIBBPF):
    @if [ ! -d $(LIBBPF_DIR) ]; then \
        echo "Error: Need libbpf submodule" $(LIBBPF_DIR); \
        echo "May need to run git submodule update --init";; \
        exit 1; \
    else \
        cd $(LIBBPF_DIR) && $(MAKE) all OBJDIR=.; \
        mkdir -p build; $(MAKE) install_headers DESTDIR=build OBJDIR=.; \
    fi

$(OBJECT_LIBXDP):
    @if [ ! -d $(LIBXDP_DIR) ]; then \
        echo "Error: Need libxdp submodule" $(LIBXDP_DIR); \
        echo "May need to run git submodule update --init";; \
        exit 1; \
    else \
        cd $(LIBXDP_DIR) && $(MAKE) all OBJDIR=.; \
    fi

# Create dependency: detect if C-file change and touch H-file, to trigger
# target $(COMMON_OBJS)
$(COMMON_H): %.h: %.c
    touch $@

# Detect if any of common obj changed and create dependency on .h-files
$(COMMON_OBJS): %.o: %.h
    $(Q)$(MAKE) -C $(COMMON_DIR)

$(USER_TARGETS): %: %.c  $(OBJECT_LIBBPF) $(OBJECT_LIBXDP) Makefile $(COMMON_MK) $(COMMON_OBJS) $(KERN_USER_H) $(EXTRA_DEPS)
    $(QUIET_CC)$(CC) -Wall $(CFLAGS) $(LDFLAGS) -o $@ $(COMMON_OBJS) $(LIB_OBJS) \
     $< $(LDLIBS)

$(XDP_OBJ): %.o: %.c  Makefile $(COMMON_MK) $(KERN_USER_H) $(EXTRA_DEPS) $(OBJECT_LIBBPF)
    $(QUIET_CLANG)$(CLANG) -S \
        -target bpf \
        -D __BPF_TRACING__ \
        $(BPF_CFLAGS) \
        -Wall \
        -Wno-unused-value \
        -Wno-pointer-sign \
        -Wno-compare-distinct-pointer-types \
        -Werror \
        -O2 -emit-llvm -c -g -o ${@:.o=.ll} $<
    $(QUIET_LLC)$(LLC) -march=bpf -filetype=obj -o $@ ${@:.o=.ll}

问题原因 #

错误根源是libxdp子模块未完整拉取或编译失败。common.mk中尝试构建../lib/install/lib/libxdp.a时，libxdp子模块的Makefile没有对应的all目标，或者子模块目录为空。

解决步骤 #

1. 拉取完整子模块 #

在教程仓库根目录执行：

git submodule update --init --recursive

该命令会拉取所有依赖的子模块（包括libbpf、libxdp、xdp-tools等），确保目录结构完整。

2. 手动编译并安装libxdp #

进入libxdp目录并执行编译安装：

cd ../lib/libxdp
make
make install DESTDIR=../install

这会将libxdp编译后安装到../lib/install目录，满足common.mk对libxdp.a的依赖要求。

3. 重新编译basic01-xdp-pass #

回到basic01目录执行make：

cd ../../basic01-xdp-pass
make

额外检查（可选） #

确认../lib/defines.mk中关于libxdp的路径定义正确，应该包含：

OBJECT_LIBXDP = $(LIB_DIR)/install/lib/libxdp.a
LIBXDP_DIR = $(LIB_DIR)/libxdp

如果路径不符，手动调整defines.mk中的对应变量。

验证 #

执行完上述步骤后，目录下应该成功生成xdp_pass_kern.o（BPF程序目标文件）和xdp_pass_user（用户态加载程序）。

内容的提问来源于stack exchange，提问作者Sultan Muhammad