This reverts commit a777e18f1bcd32528ff5dfd10a6629b655b05eb8.

In commit a777e18f1bcd ("bpftool: Use libbpf 1.0 API mode instead of
RLIMIT_MEMLOCK"), we removed the rlimit bump in bpftool, because the
kernel has switched to memcg-based memory accounting. Thanks to the
LIBBPF_STRICT_AUTO_RLIMIT_MEMLOCK, we attempted to keep compatibility
with other systems and ask libbpf to raise the limit for us if
necessary.

How do we know if memcg-based accounting is supported? There is a probe
in libbpf to check this. But this probe currently relies on the
availability of a given BPF helper, bpf_ktime_get_coarse_ns(), which
landed in the same kernel version as the memory accounting change. This
works in the generic case, but it may fail, for example, if the helper
function has been backported to an older kernel. This has been observed
for Google Cloud's Container-Optimized OS (COS), where the helper is
available but rlimit is still in use. The probe succeeds, the rlimit is
not raised, and probing features with bpftool, for example, fails.

A patch was submitted [0] to update this probe in libbpf, based on what
the cilium/ebpf Go library does [1]. It would lower the soft rlimit to
0, attempt to load a BPF object, and reset the rlimit. But it may induce
some hard-to-debug flakiness if another process starts, or the current
application is killed, while the rlimit is reduced, and the approach was
discarded.

As a workaround to ensure that the rlimit bump does not depend on the
availability of a given helper, we restore the unconditional rlimit bump
in bpftool for now.

  [0] https://lore.kernel.org/bpf/20220609143614.97837-1-quentin@isovalent.com/
  [1] https://github.com/cilium/ebpf/blob/v0.9.0/rlimit/rlimit.go#L39

Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Yafang Shao <laoar.shao@gmail.com>
Cc: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20220610112648.29695-2-quentin@isovalent.com

We have switched to memcg-based memory accouting and thus the rlimit is
not needed any more. LIBBPF_STRICT_AUTO_RLIMIT_MEMLOCK was introduced in
libbpf for backward compatibility, so we can use it instead now.

libbpf_set_strict_mode always return 0, so we don't need to check whether
the return value is 0 or not.

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220409125958.92629-4-laoar.shao@gmail.com

libbpf bpf_map__def() API is being deprecated, replace bpftool's
usage with the appropriate getters and setters

Signed-off-by: Christy Lee <christylee@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220108004218.355761-3-christylee@fb.com

Switch all the uses of to-be-deprecated bpf_object__load_xattr() into
a simple bpf_object__load() calls with optional log_level passed through
open_opts.kernel_log_level, if -d option is specified.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211209193840.1248570-13-andrii@kernel.org

Currently, LIBBPF_STRICT_ALL mode is enabled by default for
bpftool which means on error cases, some libbpf APIs would
return NULL pointers. This makes IS_ERR check failed to detect
such cases and result in segfault error. Use libbpf_get_error()
instead like we do in libbpf itself.

Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211115012436.3143318-1-hengqi.chen@gmail.com

Per [0], callers of libbpf functions with LIBBPF_STRICT_DIRECT_ERRS set
should handle negative error codes of various values (e.g. -EINVAL).
Migrate two callsites which were explicitly checking for -1 only to
handle the new scheme.

  [0]: https://github.com/libbpf/libbpf/wiki/Libbpf-1.0-migration-guide#direct-error-code-returning-libbpf_strict_direct_errs

Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Quentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/20211101224357.2651181-2-davemarchevsky@fb.com

All bpftool commands support the options for JSON output and debug from
libbpf. In addition, some commands support additional options
corresponding to specific use cases.

The list of options described in the man pages for the different
commands are not always accurate. The messages for interactive help are
mostly limited to HELP_SPEC_OPTIONS, and are even less representative of
the actual set of options supported for the commands.

Let's update the lists:

- HELP_SPEC_OPTIONS is modified to contain the "default" options (JSON
  and debug), and to be extensible (no ending curly bracket).
- All commands use HELP_SPEC_OPTIONS in their help message, and then
  complete the list with their specific options.
- The lists of options in the man pages are updated.
- The formatting of the list for bpftool.rst is adjusted to match
  formatting for the other man pages. This is for consistency, and also
  because it will be helpful in a future patch to automatically check
  that the files are synchronised.

Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210730215435.7095-5-quentin@isovalent.com

This is a clean-up for the formatting of the do_help functions for
bpftool's subcommands. The following fixes are included:

- Do not use argv[-2] for "iter" help message, as the help is shown by
  default if no "iter" action is selected, resulting in messages looking
  like "./bpftool bpftool pin...".

- Do not print unused HELP_SPEC_PROGRAM in help message for "bpftool
  link".

- Andrii used argument indexing to avoid having multiple occurrences of
  bin_name and argv[-2] in the fprintf() for the help message, for
  "bpftool gen" and "bpftool link". Let's reuse this for all other help
  functions. We can remove up to thirty arguments for the "bpftool map"
  help message.

- Harmonise all functions, e.g. use ending quotes-comma on a separate
  line.

Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200523010751.23465-1-quentin@isovalent.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

In the prog cmd, the "-d" option turns on the verifier log.
This is missed in the "struct_ops" cmd and this patch fixes it.

Fixes: 65c93628599d ("bpftool: Add struct_ops support")
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/20200424182911.1259355-1-kafai@fb.com

In commit 65c93628599d ("bpftool: Add struct_ops support") a new
type of command named struct_ops has been added. This command requires
a kernel with CONFIG_DEBUG_INFO_BTF=y set and for retrieving BTF info
in bpftool, the helper get_btf_vmlinux() is used.

When running this command on kernel without BTF debug info, this will
lead to 'btf_vmlinux' variable being an invalid(error) pointer. And by
this, btf_free() causes a segfault when executing 'bpftool struct_ops'.

This commit adds pointer validation with IS_ERR not to free invalid
pointer, and this will fix the segfault issue.

Fixes: 65c93628599d ("bpftool: Add struct_ops support")
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200410020612.2930667-1-danieltimlee@gmail.com