linux/tools/bpf/bpftool/Documentation/bpftool-prog.rst

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

================
bpftool-prog
================
-------------------------------------------------------------------------------
tool for inspection and simple manipulation of eBPF progs
-------------------------------------------------------------------------------

:Manual section: 8

.. include:: substitutions.rst

SYNOPSIS
========

**bpftool** [*OPTIONS*] **prog** *COMMAND*

*OPTIONS* := { |COMMON_OPTIONS| |
{ **-f** | **--bpffs** } | { **-m** | **--mapcompat** } | { **-n** | **--nomount** } |
{ **-L** | **--use-loader** } }

*COMMANDS* :=
{ **show** | **list** | **dump xlated** | **dump jited** | **pin** | **load** |
**loadall** | **help** }

PROG COMMANDS
=============

| **bpftool** **prog** { **show** | **list** } [*PROG*]
| **bpftool** **prog dump xlated** *PROG* [{ **file** *FILE* | [**opcodes**] [**linum**] [**visual**] }]
| **bpftool** **prog dump jited**  *PROG* [{ **file** *FILE* | [**opcodes**] [**linum**] }]
| **bpftool** **prog pin** *PROG* *FILE*
| **bpftool** **prog** { **load** | **loadall** } *OBJ* *PATH* [**type** *TYPE*] [**map** { **idx** *IDX* | **name** *NAME* } *MAP*] [{ **offload_dev** | **xdpmeta_dev** } *NAME*] [**pinmaps** *MAP_DIR*] [**autoattach**]
| **bpftool** **prog attach** *PROG* *ATTACH_TYPE* [*MAP*]
| **bpftool** **prog detach** *PROG* *ATTACH_TYPE* [*MAP*]
| **bpftool** **prog tracelog**
| **bpftool** **prog run** *PROG* **data_in** *FILE* [**data_out** *FILE* [**data_size_out** *L*]] [**ctx_in** *FILE* [**ctx_out** *FILE* [**ctx_size_out** *M*]]] [**repeat** *N*]
| **bpftool** **prog profile** *PROG* [**duration** *DURATION*] *METRICs*
| **bpftool** **prog help**
|
| *MAP* := { **id** *MAP_ID* | **pinned** *FILE* | **name** *MAP_NAME* }
| *PROG* := { **id** *PROG_ID* | **pinned** *FILE* | **tag** *PROG_TAG* | **name** *PROG_NAME* }
| *TYPE* := {
|     **socket** | **kprobe** | **kretprobe** | **classifier** | **action** |
|     **tracepoint** | **raw_tracepoint** | **xdp** | **perf_event** | **cgroup/skb** |
|     **cgroup/sock** | **cgroup/dev** | **lwt_in** | **lwt_out** | **lwt_xmit** |
|     **lwt_seg6local** | **sockops** | **sk_skb** | **sk_msg** | **lirc_mode2** |
|     **cgroup/bind4** | **cgroup/bind6** | **cgroup/post_bind4** | **cgroup/post_bind6** |
|     **cgroup/connect4** | **cgroup/connect6** | **cgroup/connect_unix** |
|     **cgroup/getpeername4** | **cgroup/getpeername6** | **cgroup/getpeername_unix** |
|     **cgroup/getsockname4** | **cgroup/getsockname6** | **cgroup/getsockname_unix** |
|     **cgroup/sendmsg4** | **cgroup/sendmsg6** | **cgroup/sendmsg_unix** |
|     **cgroup/recvmsg4** | **cgroup/recvmsg6** | **cgroup/recvmsg_unix** | **cgroup/sysctl** |
|     **cgroup/getsockopt** | **cgroup/setsockopt** | **cgroup/sock_release** |
|     **struct_ops** | **fentry** | **fexit** | **freplace** | **sk_lookup**
| }
| *ATTACH_TYPE* := {
|     **sk_msg_verdict** | **sk_skb_verdict** | **sk_skb_stream_verdict** |
|     **sk_skb_stream_parser** | **flow_dissector**
| }
| *METRICs* := {
|     **cycles** | **instructions** | **l1d_loads** | **llc_misses** |
|     **itlb_misses** | **dtlb_misses**
| }


DESCRIPTION
===========
bpftool prog { show | list } [*PROG*]
    Show information about loaded programs.  If *PROG* is specified show
    information only about given programs, otherwise list all programs
    currently loaded on the system. In case of **tag** or **name**, *PROG* may
    match several programs which will all be shown.

    Output will start with program ID followed by program type and zero or more
    named attributes (depending on kernel version).

    Since Linux 5.1 the kernel can collect statistics on BPF programs (such as
    the total time spent running the program, and the number of times it was
    run). If available, bpftool shows such statistics. However, the kernel does
    not collect them by defaults, as it slightly impacts performance on each
    program run. Activation or deactivation of the feature is performed via the
    **kernel.bpf_stats_enabled** sysctl knob.

    Since Linux 5.8 bpftool is able to discover information about processes
    that hold open file descriptors (FDs) against BPF programs. On such kernels
    bpftool will automatically emit this information as well.

bpftool prog dump xlated *PROG* [{ file *FILE* | [opcodes] [linum] [visual] }]
    Dump eBPF instructions of the programs from the kernel. By default, eBPF
    will be disassembled and printed to standard output in human-readable
    format. In this case, **opcodes** controls if raw opcodes should be printed
    as well.

    In case of **tag** or **name**, *PROG* may match several programs which
    will all be dumped.  However, if **file** or **visual** is specified,
    *PROG* must match a single program.

    If **file** is specified, the binary image will instead be written to
    *FILE*.

    If **visual** is specified, control flow graph (CFG) will be built instead,
    and eBPF instructions will be presented with CFG in DOT format, on standard
    output.

    If the programs have line_info available, the source line will be
    displayed.  If **linum** is specified, the filename, line number and line
    column will also be displayed.

bpftool prog dump jited  *PROG* [{ file *FILE* | [opcodes] [linum] }]
    Dump jited image (host machine code) of the program.

    If *FILE* is specified image will be written to a file, otherwise it will
    be disassembled and printed to stdout. *PROG* must match a single program
    when **file** is specified.

    **opcodes** controls if raw opcodes will be printed.

    If the prog has line_info available, the source line will be displayed. If
    **linum** is specified, the filename, line number and line column will also
    be displayed.

bpftool prog pin *PROG* *FILE*
    Pin program *PROG* 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 prog { load | loadall } *OBJ* *PATH* [type *TYPE*] [map { idx *IDX* | name *NAME* } *MAP*] [{ offload_dev | xdpmeta_dev } *NAME*] [pinmaps *MAP_DIR*] [autoattach]
    Load bpf program(s) from binary *OBJ* and pin as *PATH*. **bpftool prog
    load** pins only the first program from the *OBJ* as *PATH*. **bpftool prog
    loadall** pins all programs from the *OBJ* under *PATH* directory. **type**
    is optional, if not specified program type will be inferred from section
    names. By default bpftool will create new maps as declared in the ELF
    object being loaded.  **map** parameter allows for the reuse of existing
    maps. It can be specified multiple times, each time for a different map.
    *IDX* refers to index of the map to be replaced in the ELF file counting
    from 0, while *NAME* allows to replace a map by name. *MAP* specifies the
    map to use, referring to it by **id** or through a **pinned** file. If
    **offload_dev** *NAME* is specified program will be loaded onto given
    networking device (offload). If **xdpmeta_dev** *NAME* is specified program
    will become device-bound without offloading, this facilitates access to XDP
    metadata. Optional **pinmaps** argument can be provided to pin all maps
    under *MAP_DIR* directory.

    If **autoattach** is specified program will be attached before pin. In that
    case, only the link (representing the program attached to its hook) is
    pinned, not the program as such, so the path won't show in **bpftool prog
    show -f**, only show in **bpftool link show -f**. Also, this only works
    when bpftool (libbpf) is able to infer all necessary information from the
    object file, in particular, it's not supported for all program types. If a
    program does not support autoattach, bpftool falls back to regular pinning
    for that program instead.

    Note: *PATH* must be located in *bpffs* mount. It must not contain a dot
    character ('.'), which is reserved for future extensions of *bpffs*.

bpftool prog attach *PROG* *ATTACH_TYPE* [*MAP*]
    Attach bpf program *PROG* (with type specified by *ATTACH_TYPE*). Most
    *ATTACH_TYPEs* require a *MAP* parameter, with the exception of
    *flow_dissector* which is attached to current networking name space.

bpftool prog detach *PROG* *ATTACH_TYPE* [*MAP*]
    Detach bpf program *PROG* (with type specified by *ATTACH_TYPE*). Most
    *ATTACH_TYPEs* require a *MAP* parameter, with the exception of
    *flow_dissector* which is detached from the current networking name space.

bpftool prog tracelog
    Dump the trace pipe of the system to the console (stdout). Hit <Ctrl+C> to
    stop printing. BPF programs can write to this trace pipe at runtime with
    the **bpf_trace_printk**\ () helper. This should be used only for debugging
    purposes. For streaming data from BPF programs to user space, one can use
    perf events (see also **bpftool-map**\ (8)).

bpftool prog run *PROG* data_in *FILE* [data_out *FILE* [data_size_out *L*]] [ctx_in *FILE* [ctx_out *FILE* [ctx_size_out *M*]]] [repeat *N*]
    Run BPF program *PROG* in the kernel testing infrastructure for BPF,
    meaning that the program works on the data and context provided by the
    user, and not on actual packets or monitored functions etc. Return value
    and duration for the test run are printed out to the console.

    Input data is read from the *FILE* passed with **data_in**. If this *FILE*
    is "**-**", input data is read from standard input. Input context, if any,
    is read from *FILE* passed with **ctx_in**. Again, "**-**" can be used to
    read from standard input, but only if standard input is not already in use
    for input data. If a *FILE* is passed with **data_out**, output data is
    written to that file. Similarly, output context is written to the *FILE*
    passed with **ctx_out**. For both output flows, "**-**" can be used to
    print to the standard output (as plain text, or JSON if relevant option was
    passed). If output keywords are omitted, output data and context are
    discarded. Keywords **data_size_out** and **ctx_size_out** are used to pass
    the size (in bytes) for the output buffers to the kernel, although the
    default of 32 kB should be more than enough for most cases.

    Keyword **repeat** is used to indicate the number of consecutive runs to
    perform. Note that output data and context printed to files correspond to
    the last of those runs. The duration printed out at the end of the runs is
    an average over all runs performed by the command.

    Not all program types support test run. Among those which do, not all of
    them can take the **ctx_in**/**ctx_out** arguments. bpftool does not
    perform checks on program types.

bpftool prog profile *PROG* [duration *DURATION*] *METRICs*
    Profile *METRICs* for bpf program *PROG* for *DURATION* seconds or until
    user hits <Ctrl+C>. *DURATION* is optional. If *DURATION* is not specified,
    the profiling will run up to **UINT_MAX** seconds.

bpftool prog help
    Print short help message.

OPTIONS
=======
.. include:: common_options.rst

-f, --bpffs
    When showing BPF programs, show file names of pinned programs.

-m, --mapcompat
    Allow loading maps with unknown map definitions.

-n, --nomount
    Do not automatically attempt to mount any virtual file system (such as
    tracefs or BPF virtual file system) when necessary.

-L, --use-loader
    Load program as a "loader" program. This is useful to debug the generation
    of such programs. When this option is in use, bpftool attempts to load the
    programs from the object file into the kernel, but does not pin them
    (therefore, the *PATH* must not be provided).

    When combined with the **-d**\ \|\ **--debug** option, additional debug
    messages are generated, and the execution of the loader program will use
    the **bpf_trace_printk**\ () helper to log each step of loading BTF,
    creating the maps, and loading the programs (see **bpftool prog tracelog**
    as a way to dump those messages).

EXAMPLES
========
**# bpftool prog show**

::

    10: xdp  name some_prog  tag 005a3d2123620c8b  gpl run_time_ns 81632 run_cnt 10
            loaded_at 2017-09-29T20:11:00+0000  uid 0
            xlated 528B  jited 370B  memlock 4096B  map_ids 10
            pids systemd(1)

**# bpftool --json --pretty prog show**

::

    [{
            "id": 10,
            "type": "xdp",
            "tag": "005a3d2123620c8b",
            "gpl_compatible": true,
            "run_time_ns": 81632,
            "run_cnt": 10,
            "loaded_at": 1506715860,
            "uid": 0,
            "bytes_xlated": 528,
            "jited": true,
            "bytes_jited": 370,
            "bytes_memlock": 4096,
            "map_ids": [10
            ],
            "pids": [{
                    "pid": 1,
                    "comm": "systemd"
                }
            ]
        }
    ]

|
| **# bpftool prog dump xlated id 10 file /tmp/t**
| **$ ls -l /tmp/t**

::

    -rw------- 1 root root 560 Jul 22 01:42 /tmp/t

**# bpftool prog dump jited tag 005a3d2123620c8b**

::

    0:   push   %rbp
    1:   mov    %rsp,%rbp
    2:   sub    $0x228,%rsp
    3:   sub    $0x28,%rbp
    4:   mov    %rbx,0x0(%rbp)

|
| **# mount -t bpf none /sys/fs/bpf/**
| **# bpftool prog pin id 10 /sys/fs/bpf/prog**
| **# bpftool prog load ./my_prog.o /sys/fs/bpf/prog2**
| **# ls -l /sys/fs/bpf/**

::

    -rw------- 1 root root 0 Jul 22 01:43 prog
    -rw------- 1 root root 0 Jul 22 01:44 prog2

**# bpftool prog dump jited pinned /sys/fs/bpf/prog opcodes**

::

   0:   push   %rbp
        55
   1:   mov    %rsp,%rbp
        48 89 e5
   4:   sub    $0x228,%rsp
        48 81 ec 28 02 00 00
   b:   sub    $0x28,%rbp
        48 83 ed 28
   f:   mov    %rbx,0x0(%rbp)
        48 89 5d 00

|
| **# bpftool prog load xdp1_kern.o /sys/fs/bpf/xdp1 type xdp map name rxcnt id 7**
| **# bpftool prog show pinned /sys/fs/bpf/xdp1**

::

    9: xdp  name xdp_prog1  tag 539ec6ce11b52f98  gpl
            loaded_at 2018-06-25T16:17:31-0700  uid 0
            xlated 488B  jited 336B  memlock 4096B  map_ids 7

**# rm /sys/fs/bpf/xdp1**

|
| **# bpftool prog profile id 337 duration 10 cycles instructions llc_misses**

::

         51397 run_cnt
      40176203 cycles                                                 (83.05%)
      42518139 instructions    #   1.06 insns per cycle               (83.39%)
           123 llc_misses      #   2.89 LLC misses per million insns  (83.15%)

|
| Output below is for the trace logs.
| Run in separate terminals:
| **# bpftool prog tracelog**
| **# bpftool prog load -L -d file.o**

::

    bpftool-620059  [004] d... 2634685.517903: bpf_trace_printk: btf_load size 665 r=5
    bpftool-620059  [004] d... 2634685.517912: bpf_trace_printk: map_create sample_map idx 0 type 2 value_size 4 value_btf_id 0 r=6
    bpftool-620059  [004] d... 2634685.517997: bpf_trace_printk: prog_load sample insn_cnt 13 r=7
    bpftool-620059  [004] d... 2634685.517999: bpf_trace_printk: close(5) = 0