diff --git a/README b/README index a48fdde..9adc1fc 100644 --- a/README +++ b/README @@ -19,14 +19,27 @@ successful. Build ===== +libelf is an internal dependency of libbpf and thus it is required to link +against and must be installed on the system for applications to work. +pkg-config is used by default to find libelf, and the program called can be +overridden with PKG_CONFIG. +If using pkg-config at build time is not desired, it can be disabled by setting +NO_PKG_CONFIG=1 when calling make. -To build static library libbpf.a: +To build both static libbpf.a and shared libbpf.so: cd src make -To build both static libbpf.a and shared libbpf.so libraries in directory +To build only static libbpf.a library in directory build/ and install them together with libbpf headers in a staging directory root/: cd src mkdir build root - BUILD_SHARED=y OBJDIR=build DESTDIR=root make install + BUILD_STATIC_ONLY=y OBJDIR=build DESTDIR=root make install + +To build both static libbpf.a and shared libbpf.so against a custom libelf +dependency installed in /build/root/ and install them together with libbpf +headers in a build directory /build/root/: + + cd src + PKG_CONFIG_PATH=/build/root/lib64/pkgconfig DESTDIR=/build/root make install diff --git a/src/Makefile b/src/Makefile index 51b52e8..b825956 100644 --- a/src/Makefile +++ b/src/Makefile @@ -10,12 +10,20 @@ ifneq ($(FEATURE_REALLOCARRAY),) ALL_CFLAGS += -DCOMPAT_NEED_REALLOCARRAY endif -ifdef BUILD_SHARED +ifndef BUILD_STATIC_ONLY ALL_CFLAGS += -fPIC -fvisibility=hidden endif CFLAGS ?= -g -O2 -Werror -Wall ALL_CFLAGS += $(CFLAGS) +ALL_LDFLAGS += $(LDFLAGS) +ifdef NO_PKG_CONFIG + ALL_LDFLAGS += -lelf +else + PKG_CONFIG ?= pkg-config + ALL_CFLAGS += $(shell $(PKG_CONFIG) --cflags libelf) + ALL_LDFLAGS += $(shell $(PKG_CONFIG) --libs libelf) +endif OBJDIR ?= . @@ -23,7 +31,7 @@ OBJS := $(addprefix $(OBJDIR)/,bpf.o btf.o libbpf.o libbpf_errno.o netlink.o \ nlattr.o str_error.o libbpf_probes.o bpf_prog_linfo.o xsk.o) LIBS := $(OBJDIR)/libbpf.a -ifdef BUILD_SHARED +ifndef BUILD_STATIC_ONLY LIBS += $(OBJDIR)/libbpf.so endif @@ -54,7 +62,7 @@ $(OBJDIR)/libbpf.a: $(OBJS) $(AR) rcs $@ $^ $(OBJDIR)/libbpf.so: $(OBJS) - $(CC) -shared $(LDFLAGS) $^ -o $@ + $(CC) -shared $(ALL_LDFLAGS) $^ -o $@ $(OBJDIR)/libbpf.pc: sed -e "s|@PREFIX@|$(PREFIX)|" \