2f81310ec0
Syncing latest libbpf commits from kernel repository.
Baseline bpf-next commit: 98e20e5e13d2811898921f999288be7151a11954
Checkpoint bpf-next commit: c8632acf193beac64bbdaebef013368c480bf74f
Baseline bpf commit: 7c5e046bdcb2513f9decb3765d8bf92d604279cf
Checkpoint bpf commit: 0a5bd0ffe790511d802e7f40898429a89e2487df
Andrey Grafin (1):
libbpf: Apply map_set_def_max_entries() for inner_maps on creation
Andrii Nakryiko (17):
libbpf: feature-detect arg:ctx tag support in kernel
libbpf: warn on unexpected __arg_ctx type when rewriting BTF
libbpf: call dup2() syscall directly
bpf: Introduce BPF token object
bpf: Add BPF token support to BPF_MAP_CREATE command
bpf: Add BPF token support to BPF_BTF_LOAD command
bpf: Add BPF token support to BPF_PROG_LOAD command
libbpf: Add bpf_token_create() API
libbpf: Add BPF token support to bpf_map_create() API
libbpf: Add BPF token support to bpf_btf_load() API
libbpf: Add BPF token support to bpf_prog_load() API
libbpf: Split feature detectors definitions from cached results
libbpf: Further decouple feature checking logic from bpf_object
libbpf: Move feature detection code into its own file
libbpf: Wire up token_fd into feature probing logic
libbpf: Wire up BPF token support at BPF object level
libbpf: Support BPF token path setting through LIBBPF_BPF_TOKEN_PATH
envvar
Daniel Borkmann (1):
bpf: Sync uapi bpf.h header for the tooling infra
Dima Tisnek (1):
libbpf: Correct bpf_core_read.h comment wrt bpf_core_relo struct
Jiri Olsa (2):
bpf: Add cookie to perf_event bpf_link_info records
bpf: Store cookies in kprobe_multi bpf_link_info data
Kan Liang (2):
perf: Add branch stack counters
perf/x86/intel: Support branch counters logging
Kui-Feng Lee (3):
bpf: pass btf object id in bpf_map_info.
bpf: pass attached BTF to the bpf_struct_ops subsystem
libbpf: Find correct module BTFs for struct_ops maps and progs.
Martin KaFai Lau (1):
libbpf: Ensure undefined bpf_attr field stays 0
include/uapi/linux/bpf.h | 79 +++-
include/uapi/linux/perf_event.h | 13 +
src/bpf.c | 42 +-
src/bpf.h | 38 +-
src/bpf_core_read.h | 2 +-
src/btf.c | 10 +-
src/elf.c | 2 -
src/features.c | 503 +++++++++++++++++++++
src/libbpf.c | 744 ++++++++++++--------------------
src/libbpf.h | 21 +-
src/libbpf.map | 1 +
src/libbpf_internal.h | 50 ++-
src/libbpf_probes.c | 12 +-
src/str_error.h | 3 +
14 files changed, 1019 insertions(+), 501 deletions(-)
create mode 100644 src/features.c
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
libbpf
This is the official home of the libbpf library.
Please use this Github repository for building and packaging libbpf and when using it in your projects through Git submodule.
Libbpf authoritative source code is developed as part of bpf-next Linux source
tree under
tools/lib/bpf subdirectory and is periodically synced to Github. As such, all the
libbpf changes should be sent to BPF mailing list,
please don't open PRs here unless you are changing Github-specific parts of libbpf
(e.g., Github-specific Makefile).
Libbpf and general BPF usage questions
Libbpf documentation can be found here. It's an ongoing effort and has ways to go, but please take a look and consider contributing as well.
Please check out libbpf-bootstrap and the companion blog post for the examples of building BPF applications with libbpf. libbpf-tools are also a good source of the real-world libbpf-based tracing tools.
See also "BPF CO-RE reference guide" for the coverage of practical aspects of building BPF CO-RE applications and "BPF CO-RE" for general introduction into BPF portability issues and BPF CO-RE origins.
All general BPF questions, including kernel functionality, libbpf APIs and their application, 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 libbpf mirror repo is set up and organized.
Building libbpf
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
BPF CO-RE (Compile Once – Run Everywhere)
Libbpf supports building BPF CO-RE-enabled applications, which, in contrast to BCC, do not require Clang/LLVM runtime being deployed to target servers and doesn't rely on kernel-devel headers being available.
It does rely on kernel to be built with BTF type information, though. Some major Linux distributions come with kernel BTF already built in:
- Fedora 31+
- RHEL 8.2+
- OpenSUSE Tumbleweed (in the next release, as of 2020-06-04)
- Arch Linux (from kernel 5.7.1.arch1-1)
- Manjaro (from kernel 5.4 if compiled after 2021-06-18)
- Ubuntu 20.10
- Debian 11 (amd64/arm64)
If your kernel doesn't come with BTF built-in, you'll need to build custom kernel. You'll need:
pahole1.16+ tool (part ofdwarvespackage), which performs DWARF to BTF conversion;- kernel built with
CONFIG_DEBUG_INFO_BTF=yoption; - you can check if your kernel has BTF built-in by looking for
/sys/kernel/btf/vmlinuxfile:
$ ls -la /sys/kernel/btf/vmlinux
-r--r--r--. 1 root root 3541561 Jun 2 18:16 /sys/kernel/btf/vmlinux
To develop and build BPF programs, you'll need Clang/LLVM 10+. The following distributions have Clang/LLVM 10+ packaged by default:
- Fedora 32+
- Ubuntu 20.04+
- Arch Linux
- Ubuntu 20.10 (LLVM 11)
- Debian 11 (LLVM 11)
- Alpine 3.13+
Otherwise, please make sure to update it on your system.
The following resources are useful to understand what BPF CO-RE is and how to use it:
- BPF CO-RE reference guide
- BPF Portability and CO-RE
- HOWTO: BCC to libbpf conversion
- libbpf-tools in BCC repo contain lots of real-world tools converted from BCC to BPF CO-RE. Consider converting some more to both contribute to the BPF community and gain some more experience with it.
Distributions
Distributions packaging libbpf from this mirror:
Benefits of packaging from the mirror over packaging from kernel sources:
- Consistent versioning across distributions.
- No ties to any specific kernel, transparent handling of older kernels. Libbpf is designed to be kernel-agnostic and work across multitude of kernel versions. It has built-in mechanisms to gracefully handle older kernels, that are missing some of the features, by working around or gracefully degrading functionality. Thus libbpf is not tied to a specific kernel version and can/should be packaged and versioned independently.
- Continuous integration testing via GitHub Actions.
- Static code analysis via LGTM and Coverity.
Package dependencies of libbpf, package names may vary across distros:
- zlib
- libelf
bpf-next to Github sync
All the gory details of syncing can be found in scripts/sync-kernel.sh
script. See SYNC.md for instruction.
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.
License
This work is dual-licensed under BSD 2-clause license and GNU LGPL v2.1 license. You can choose between one of them if you use this work.
SPDX-License-Identifier: BSD-2-Clause OR LGPL-2.1