bpftool: Use libbpf_bpf_attach_type_str

This change switches bpftool over to using the recently introduced
libbpf_bpf_attach_type_str function instead of maintaining its own
string representation for the bpf_attach_type enum.

Note that contrary to other enum types, the variant names that bpftool
maps bpf_attach_type to do not adhere a simple to follow rule. With
bpf_prog_type, for example, the textual representation can easily be
inferred by stripping the BPF_PROG_TYPE_ prefix and lowercasing the
remaining string. bpf_attach_type violates this rule for various
variants.
We decided to fix up this deficiency with this change, meaning that
bpftool uses the same textual representations as libbpf. Supporting
tests, completion scripts, and man pages have been adjusted accordingly.
However, we did add support for accepting (the now undocumented)
original attach type names when they are provided by users.

For the test (test_bpftool_synctypes.py), I have removed the enum
representation checks, because we no longer mirror the various enum
variant names in bpftool source code. For the man page, help text, and
completion script checks we are now using enum definitions from
uapi/linux/bpf.h as the source of truth directly.

Signed-off-by: Daniel Müller <deso@posteo.net>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Quentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/20220523230428.3077108-10-deso@posteo.net
8 files changed
tree: c0aa216f27feac0115fef56ce5d1c972081cf9f0
  1. .github/
  2. bash-completion/
  3. docs/
  4. include/
  5. scripts/
  6. src/
  7. .gitmodules
  8. BPF-CHECKPOINT-COMMIT
  9. CHECKPOINT-COMMIT
  10. LICENSE
  11. LICENSE.BSD-2-Clause
  12. LICENSE.GPL-2.0
  13. README.md
README.md

bpftool

This is a mirror of bpf-next Linux source tree's tools/bpf/bpftool directory, plus its few dependencies from under kernel/bpf/, and its supporting header files.

All the gory details of syncing can be found in scripts/sync-kernel.sh script.

Some header files in this repo (include/linux/*.h) are reduced versions of their counterpart files at bpf-next's tools/include/linux/*.h to make compilation successful.

BPF/bpftool usage and questions

Please check out the manual pages for documentation about bpftool. A number of example invocations are also displayed in this blog post.

All general BPF questions, including kernel functionality, bpftool features and usage, should be sent to bpf@vger.kernel.org mailing list. You can subscribe to it here and search its archive here. Please search the archive before asking new questions. It very well might be that this was already addressed or answered before.

bpf@vger.kernel.org is monitored by many more people and they will happily try to help you with whatever issue you have. This repository's PRs and issues should be opened only for dealing with issues pertaining to specific way this bpftool mirror repo is set up and organized.

Dependencies

Required:

  • libelf
  • zlib

Optional:

  • libbfd (for dumping JIT-compiled program instructions)
  • libcap (for better feature probing)
  • kernel BTF information (for profiling programs or showing PIDs of processes referencing BPF objects)
  • clang/LLVM (idem)

Build build

Initialize libbpf submodule

This repository uses libbpf as a submodule. You can initialize it when cloning bpftool:

$ git clone --recurse-submodules https://github.com/libbpf/bpftool.git

Alternatively, if you have already cloned the repository, you can initialize the submodule by running the following command from within the repository:

$ git submodule update --init

Build bpftool

To build bpftool:

$ cd src
$ make

To build and install bpftool on the system:

$ cd src
# make install

Building bpftool in a separate directory is supported via the OUTPUT variable:

$ mkdir /tmp/bpftool
$ cd src
$ OUTPUT=/tmp/bpftool make

Most of the output is suppressed by default, but detailed building logs can be displayed by passing V=1:

$ cd src
$ make V=1

Additional CFLAGS can be passed to the command line if required. For example, we can create a static build with the following commands (but note that this does not work out-of-the-box when linking with libbfd):

$ cd src
$ CFLAGS=--static make

Build bpftool's man pages

The man pages for bpftool can be built with:

$ cd docs
$ make

They can be installed on the system with:

$ cd docs
# make install

License

This work is dual-licensed under the GNU GPL v2.0 (only) license and the BSD 2-clause license. You can choose between one of them if you use this work.

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