2020-04-23 22:35 UTC-0700 ~ Andrii Nakryiko <andriin@xxxxxx>
> Add bpftool-link manpage with information and examples of link-related
> commands.
>
> Signed-off-by: Andrii Nakryiko <andriin@xxxxxx>
> ---
> .../bpftool/Documentation/bpftool-link.rst | 119 ++++++++++++++++++
> 1 file changed, 119 insertions(+)
> create mode 100644 tools/bpf/bpftool/Documentation/bpftool-link.rst
>
> diff --git a/tools/bpf/bpftool/Documentation/bpftool-link.rst b/tools/bpf/bpftool/Documentation/bpftool-link.rst
> new file mode 100644
> index 000000000000..2866128cd6b2
> --- /dev/null
> +++ b/tools/bpf/bpftool/Documentation/bpftool-link.rst
> @@ -0,0 +1,119 @@
> +================
> +bpftool-link
> +================
> +-------------------------------------------------------------------------------
> +tool for inspection and simple manipulation of eBPF links
> +-------------------------------------------------------------------------------
> +
> +:Manual section: 8
> +
> +SYNOPSIS
> +========
> +
> + **bpftool** [*OPTIONS*] **link *COMMAND*
Missing the ending "**" after "**link", please fix.
> +
> + *OPTIONS* := { { **-j** | **--json** } [{ **-p** | **--pretty** }] | { **-f** | **--bpffs** } }
> +
> + *COMMANDS* := { **show** | **list** | **pin** | **help** }
> +
> +LINK COMMANDS
> +=============
> +
> +| **bpftool** **link { show | list }** [*LINK*]
> +| **bpftool** **link pin** *LINK* *FILE*
> +| **bpftool** **link help**
> +|
> +| *LINK* := { **id** *LINK_ID* | **pinned** *FILE* }
> +
> +
> +DESCRIPTION
> +===========
> + **bpftool link { show | list }** [*LINK*]
> + Show information about active links. If *LINK* is
> + specified show information only about given link,
> + otherwise list all links currently active on the system.
> +
> + Output will start with link ID followed by link type and
> + zero or more named attributes, some of which depend on type
> + of link.
Nit: indent issue on the line above.
> +
> + **bpftool link pin** *LINK* *FILE*
> + Pin link *LINK* as *FILE*.
> +
> + Note: *FILE* must be located in *bpffs* mount. It must not
> + contain a dot character ('.'), which is reserved for future
> + extensions of *bpffs*.
> +
> + **bpftool link help**
> + Print short help message.
> +
> +OPTIONS
> +=======
> + -h, --help
> + Print short generic help message (similar to **bpftool help**).
> +
> + -V, --version
> + Print version number (similar to **bpftool version**).
> +
> + -j, --json
> + Generate JSON output. For commands that cannot produce JSON, this
> + option has no effect.
> +
> + -p, --pretty
> + Generate human-readable JSON output. Implies **-j**.
> +
> + -f, --bpffs
> + When showing BPF links, show file names of pinned
> + links.
> +
> + -n, --nomount
> + Do not automatically attempt to mount any virtual file system
> + (such as tracefs or BPF virtual file system) when necessary.
> +
> + -d, --debug
> + Print all logs available, even debug-level information. This
> + includes logs from libbpf.
> +
> +EXAMPLES
> +========
> +**# bpftool link show**
> +
> +::
> +
> + 10: cgroup prog 25
> + cgroup_id 614 attach_type egress
> +
> +**# bpftool --json --pretty link show**
> +
> +::
> +
> + [{
> + "type": "cgroup",
> + "prog_id": 25,
> + "cgroup_id": 614,
> + "attach_type": "egress"
> + }
> + ]
> +
> +|
> +| **# mount -t bpf none /sys/fs/bpf/**
[ Mounting should not be required, as you call
do_pin_any()->do_pin_fd()->mount_bpffs_for_pin().
Although on second thought I'm fine with keeping it, just in case users
call bpftool --nomount. ]
> +| **# bpftool link pin id 10 /sys/fs/bpf/link**
> +| **# ls -l /sys/fs/bpf/**
> +
> +::
> +
> + -rw------- 1 root root 0 Apr 23 21:39 link
> +
> +
> +SEE ALSO
> +========
> + **bpf**\ (2),
> + **bpf-helpers**\ (7),
> + **bpftool**\ (8),
> + **bpftool-prog\ (8),
> + **bpftool-map**\ (8),
> + **bpftool-cgroup**\ (8),
> + **bpftool-feature**\ (8),
> + **bpftool-net**\ (8),
> + **bpftool-perf**\ (8),
> + **bpftool-btf**\ (8)
>
