Documentation/bpf/libbpf/libbpf_overview.rst

Source file repositories/reference/linux-study-clean/Documentation/bpf/libbpf/libbpf_overview.rst

File Facts

System
Linux kernel
Corpus path
Documentation/bpf/libbpf/libbpf_overview.rst
Extension
.rst
Size
11321 bytes
Lines
237
Domain
Support Tooling And Documentation
Bucket
Documentation
Inferred role
Support Tooling And Documentation: documentation
Status
atlas-only

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

if (err) {
      /* handle error */
    }

    /* parent_task contains the value of task->parent pointer */

In the code snippet, we first get a pointer to the current ``task_struct`` using
``bpf_get_current_task()``.  We then use ``bpf_core_read()`` to read the parent
field of task struct into the ``parent_task`` variable. ``bpf_core_read()`` is
just like ``bpf_probe_read_kernel()`` BPF helper, except it records information
about the field that should be relocated on the target kernel. i.e, if the
``parent`` field gets shifted to a different offset within
``struct task_struct`` due to some new field added in front of it, libbpf will
automatically adjust the actual offset to the proper value.

Getting Started with libbpf
===========================

Check out the `libbpf-bootstrap <https://github.com/libbpf/libbpf-bootstrap>`_
repository with simple examples of using libbpf to build various BPF
applications.

See also `libbpf API documentation
<https://libbpf.readthedocs.io/en/latest/api.html>`_.

libbpf and Rust
===============

If you are building BPF applications in Rust, it is recommended to use the
`Libbpf-rs <https://github.com/libbpf/libbpf-rs>`_ library instead of bindgen
bindings directly to libbpf. Libbpf-rs wraps libbpf functionality in
Rust-idiomatic interfaces and provides libbpf-cargo plugin to handle BPF code
compilation and skeleton generation. Using Libbpf-rs will make building user
space part of the BPF application easier. Note that the BPF program themselves
must still be written in plain C.

libbpf logging
==============

By default, libbpf logs informational and warning messages to stderr. The
verbosity of these messages can be controlled by setting the environment
variable LIBBPF_LOG_LEVEL to either warn, info, or debug. A custom log
callback can be set using ``libbpf_set_print()``.

Additional Documentation
========================

* `Program types and ELF Sections <https://libbpf.readthedocs.io/en/latest/program_types.html>`_
* `API naming convention <https://libbpf.readthedocs.io/en/latest/libbpf_naming_convention.html>`_
* `Building libbpf <https://libbpf.readthedocs.io/en/latest/libbpf_build.html>`_
* `API documentation Convention <https://libbpf.readthedocs.io/en/latest/libbpf_naming_convention.html#api-documentation-convention>`_

Annotation

Implementation Notes