e64e62d19f
Libbpf does sanitization of BTF before loading it into kernel, if kernel doesn't support some of newer BTF features. This removes some of the important information from BTF (e.g., DATASEC and VAR description), which will be used for map construction. This patch splits BTF processing into initialization step, in which BTF is initialized from ELF and all the original data is still preserved; and sanitization/loading step, which ensures that BTF is safe to load into kernel. This allows to use full BTF information to construct maps, while still loading valid BTF into older kernels. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Song Liu <songliubraving@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This is a mirror of bpf-next linux tree's
tools/lib/bpf directory plus its supporting header files.
The following files will by sync'ed with bpf-next repo:
src/<->bpf-next/tools/lib/bpf/include/uapi/linux/bpf_common.h<->bpf-next/tools/include/uapi/linux/bpf_common.hinclude/uapi/linux/bpf.h<->bpf-next/tools/include/uapi/linux/bpf.hinclude/uapi/linux/btf.h<->bpf-next/tools/include/uapi/linux/btf.hinclude/uapi/linux/if_link.h<->bpf-next/tools/include/uapi/linux/if_link.hinclude/uapi/linux/if_xdp.h<->bpf-next/tools/include/uapi/linux/if_xdp.hinclude/uapi/linux/netlink.h<->bpf-next/tools/include/uapi/linux/netlink.hinclude/tools/libc_compat.h<->bpf-next/tools/include/tools/libc_compat.h
Other header files at this repo (include/linux/*.h) are reduced versions of
their counterpart files at bpf-next's tools/include/linux/*.h to make compilation
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 both static libbpf.a and shared libbpf.so:
$ cd src
$ make
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_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
To integrate libbpf into a project which uses Meson building system define
[wrap-git] file in subprojects folder.
To add libbpf dependency to the parent parent project, e.g. for
libbpf_static_dep:
libbpf_obj = subproject('libbpf', required : true)
libbpf_static_dep = libbpf_proj.get_variable('libbpf_static_dep')
To validate changes to meson.build
$ python3 meson.py build
$ ninja -C build/
To install headers, libs and pkgconfig
$ cd build
$ ninja install