tools/bpf/bpftool/Documentation/bpftool-feature.rst

Source file repositories/reference/linux-study-clean/tools/bpf/bpftool/Documentation/bpftool-feature.rst

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tools/bpf/bpftool/Documentation/bpftool-feature.rst
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Support Tooling And Documentation
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Support Tooling And Documentation: documentation
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Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

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

===============
bpftool-feature
===============
-------------------------------------------------------------------------------
tool for inspection of eBPF-related parameters for Linux kernel or net device
-------------------------------------------------------------------------------

:Manual section: 8

.. include:: substitutions.rst

SYNOPSIS
========

**bpftool** [*OPTIONS*] **feature** *COMMAND*

*OPTIONS* := { |COMMON_OPTIONS| }

*COMMANDS* := { **probe** | **help** }

FEATURE COMMANDS
================

| **bpftool** **feature probe** [*COMPONENT*] [**full**] [**unprivileged**] [**macros** [**prefix** *PREFIX*]]
| **bpftool** **feature list_builtins** *GROUP*
| **bpftool** **feature help**
|
| *COMPONENT* := { **kernel** | **dev** *NAME* }
| *GROUP* := { **prog_types** | **map_types** | **attach_types** | **link_types** | **helpers** }

DESCRIPTION
===========
bpftool feature probe [kernel] [full] [macros [prefix *PREFIX*]]
    Probe the running kernel and dump a number of eBPF-related parameters, such
    as availability of the **bpf**\ () system call, JIT status, eBPF program
    types availability, eBPF helper functions availability, and more.

    By default, bpftool **does not run probes** for **bpf_probe_write_user**\
    () and **bpf_trace_printk**\() helpers which print warnings to kernel logs.
    To enable them and run all probes, the **full** keyword should be used.

    If the **macros** keyword (but not the **-j** option) is passed, a subset
    of the output is dumped as a list of **#define** macros that are ready to
    be included in a C header file, for example. If, additionally, **prefix**
    is used to define a *PREFIX*, the provided string will be used as a prefix
    to the names of the macros: this can be used to avoid conflicts on macro
    names when including the output of this command as a header file.

    Keyword **kernel** can be omitted. If no probe target is specified, probing
    the kernel is the default behaviour.

    When the **unprivileged** keyword is used, bpftool will dump only the
    features available to a user who does not have the **CAP_SYS_ADMIN**
    capability set. The features available in that case usually represent a
    small subset of the parameters supported by the system. Unprivileged users
    MUST use the **unprivileged** keyword: This is to avoid misdetection if
    bpftool is inadvertently run as non-root, for example. This keyword is
    unavailable if bpftool was compiled without libcap.

bpftool feature probe dev *NAME* [full] [macros [prefix *PREFIX*]]
    Probe network device for supported eBPF features and dump results to the
    console.

    The keywords **full**, **macros** and **prefix** have the same role as when
    probing the kernel.

bpftool feature list_builtins *GROUP*
    List items known to bpftool. These can be BPF program types

Annotation

Implementation Notes