Quentin Monnet 55d778076b tools: bpftool: make -d option print debug output from verifier
The "-d" option is used to require all logs available for bpftool. So
far it meant telling libbpf to print even debug-level information. But
there is another source of info that can be made more verbose: when we
attemt to load programs with bpftool, we can pass a log_level parameter
to the verifier in order to control the amount of information that is
printed to the console.

Reuse the "-d" option to print all information the verifier can tell. At
this time, this means logs related to BPF_LOG_LEVEL1, BPF_LOG_LEVEL2 and
BPF_LOG_STATS. As mentioned in the discussion on the first version of
this set, these macros are internal to the kernel
(include/linux/bpf_verifier.h) and are not meant to be part of the
stable user API, therefore we simply use the related constants to print
whatever we can at this time, without trying to tell users what is
log_level1 or what is statistics.

Verifier logs are only used when loading programs for now (In the
future: for loading BTF objects with bpftool? Although libbpf does not
currently offer to print verifier info at debug level if no error
occurred when loading BTF objects), so bpftool.rst and bpftool-prog.rst
are the only man pages to get the update.

v3:
- Add details on log level and BTF loading at the end of commit log.

v2:
- Remove the possibility to select the log levels to use (v1 offered a
  combination of "log_level1", "log_level2" and "stats").
- The macros from kernel header bpf_verifier.h are not used (and
  therefore not moved to UAPI header).
- In v1 this was a distinct option, but is now merged in the only "-d"
  switch to activate libbpf and verifier debug-level logs all at the
  same time.

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>
2019-05-28 11:03:26 +02:00

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ReStructuredText

================
BPFTOOL
================
-------------------------------------------------------------------------------
tool for inspection and simple manipulation of eBPF programs and maps
-------------------------------------------------------------------------------
:Manual section: 8
SYNOPSIS
========
**bpftool** [*OPTIONS*] *OBJECT* { *COMMAND* | **help** }
**bpftool** **batch file** *FILE*
**bpftool** **version**
*OBJECT* := { **map** | **program** | **cgroup** | **perf** | **net** | **feature** }
*OPTIONS* := { { **-V** | **--version** } | { **-h** | **--help** }
| { **-j** | **--json** } [{ **-p** | **--pretty** }] }
*MAP-COMMANDS* :=
{ **show** | **list** | **create** | **dump** | **update** | **lookup** | **getnext**
| **delete** | **pin** | **event_pipe** | **help** }
*PROG-COMMANDS* := { **show** | **list** | **dump jited** | **dump xlated** | **pin**
| **load** | **attach** | **detach** | **help** }
*CGROUP-COMMANDS* := { **show** | **list** | **attach** | **detach** | **help** }
*PERF-COMMANDS* := { **show** | **list** | **help** }
*NET-COMMANDS* := { **show** | **list** | **help** }
*FEATURE-COMMANDS* := { **probe** | **help** }
DESCRIPTION
===========
*bpftool* allows for inspection and simple modification of BPF objects
on the system.
Note that format of the output of all tools is not guaranteed to be
stable and should not be depended upon.
OPTIONS
=======
-h, --help
Print short 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**.
-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.
-d, --debug
Print all logs available, even debug-level information. This
includes logs from libbpf as well as from the verifier, when
attempting to load programs.
SEE ALSO
========
**bpf**\ (2),
**bpf-helpers**\ (7),
**bpftool-prog**\ (8),
**bpftool-map**\ (8),
**bpftool-cgroup**\ (8),
**bpftool-feature**\ (8),
**bpftool-net**\ (8),
**bpftool-perf**\ (8),
**bpftool-btf**\ (8)