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bianbu-linux-6.6/tools/bpf/bpftool/Documentation/bpftool-prog.rst
Quentin Monnet 30da46b5dc tools: bpftool: add a command to dump the trace pipe 
BPF programs can use the bpf_trace_printk() helper to print debug
information into the trace pipe. Add a subcommand
"bpftool prog tracelog" to simply dump this pipe to the console.

This is for a good part copied from iproute2, where the feature is
available with "tc exec bpf dbg". Changes include dumping pipe content
to stdout instead of stderr and adding JSON support (content is dumped
as an array of strings, one per line read from the pipe). This version
is dual-licensed, with Daniel's permission.

Cc: Daniel Borkmann <daniel@iogearbox.net>
Suggested-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-12-05 16:41:52 +01:00

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================
bpftool-prog
================
-------------------------------------------------------------------------------
tool for inspection and simple manipulation of eBPF progs
-------------------------------------------------------------------------------
:Manual section: 8
SYNOPSIS
========
**bpftool** [*OPTIONS*] **prog** *COMMAND*
*OPTIONS* := { { **-j** | **--json** } [{ **-p** | **--pretty** }] | { **-f** | **--bpffs** } }
*COMMANDS* :=
{ **show** | **list** | **dump xlated** | **dump jited** | **pin** | **load**
| **loadall** | **help** }
MAP COMMANDS
=============
| **bpftool** **prog { show | list }** [*PROG*]
| **bpftool** **prog dump xlated** *PROG* [{**file** *FILE* | **opcodes** | **visual**}]
| **bpftool** **prog dump jited** *PROG* [{**file** *FILE* | **opcodes**}]
| **bpftool** **prog pin** *PROG* *FILE*
| **bpftool** **prog { load | loadall }** *OBJ* *PATH* [**type** *TYPE*] [**map** {**idx** *IDX* | **name** *NAME*} *MAP*] [**dev** *NAME*]
| **bpftool** **prog attach** *PROG* *ATTACH_TYPE* [*MAP*]
| **bpftool** **prog detach** *PROG* *ATTACH_TYPE* [*MAP*]
| **bpftool** **prog tracelog**
| **bpftool** **prog help**
|
| *MAP* := { **id** *MAP_ID* | **pinned** *FILE* }
| *PROG* := { **id** *PROG_ID* | **pinned** *FILE* | **tag** *PROG_TAG* }
| *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/sendmsg4** | **cgroup/sendmsg6**
| }
| *ATTACH_TYPE* := {
| **msg_verdict** | **skb_verdict** | **skb_parse** | **flow_dissector**
| }
DESCRIPTION
===========
**bpftool prog { show | list }** [*PROG*]
Show information about loaded programs. If *PROG* is
specified show information only about given program, otherwise
list all programs currently loaded on the system.
Output will start with program ID followed by program type and
zero or more named attributes (depending on kernel version).
**bpftool prog dump xlated** *PROG* [{ **file** *FILE* | **opcodes** | **visual** }]
Dump eBPF instructions of the program 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.
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.
**bpftool prog dump jited** *PROG* [{ **file** *FILE* | **opcodes** }]
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.
**opcodes** controls if raw opcodes will be printed.
**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*] [**dev** *NAME*] [**pinmaps** *MAP_DIR*]
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 **dev** *NAME* is specified program will be loaded onto
given networking device (offload).
Optional **pinmaps** argument can be provided to pin all
maps under *MAP_DIR* directory.
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 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 programs, show file names of pinned
programs.
EXAMPLES
========
**# bpftool prog show**
::
10: xdp name some_prog tag 005a3d2123620c8b gpl
loaded_at Sep 29/20:11 uid 0
xlated 528B jited 370B memlock 4096B map_ids 10
**# bpftool --json --pretty prog show**
::
{
"programs": [{
"id": 10,
"type": "xdp",
"tag": "005a3d2123620c8b",
"gpl_compatible": true,
"loaded_at": "Sep 29/20:11",
"uid": 0,
"bytes_xlated": 528,
"jited": true,
"bytes_jited": 370,
"bytes_memlock": 4096,
"map_ids": [10
]
}
]
}
|
| **# 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 dum jited tag 005a3d2123620c8b**
::
push %rbp
mov %rsp,%rbp
sub $0x228,%rsp
sub $0x28,%rbp
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 dum jited pinned /sys/fs/bpf/prog opcodes**
::
push %rbp
55
mov %rsp,%rbp
48 89 e5
sub $0x228,%rsp
48 81 ec 28 02 00 00
sub $0x28,%rbp
48 83 ed 28
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**
|
SEE ALSO
========
**bpf**\ (2),
**bpf-helpers**\ (7),
**bpftool**\ (8),
**bpftool-map**\ (8),
**bpftool-cgroup**\ (8),
**bpftool-net**\ (8),
**bpftool-perf**\ (8)
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