linux.git/tools/lib/bpf/bpf.c, branch v5.14

libbpf: Streamline error reporting for low-level APIs

2021-05-26T00:32:35+00:00

Ensure that low-level APIs behave uniformly across the libbpf as follows:
  - in case of an error, errno is always set to the correct error code;
  - when libbpf 1.0 mode is enabled with LIBBPF_STRICT_DIRECT_ERRS option to
    libbpf_set_strict_mode(), return -Exxx error value directly, instead of -1;
  - by default, until libbpf 1.0 is released, keep returning -1 directly.

More context, justification, and discussion can be found in "Libbpf: the road
to v1.0" document ([0]).

  [0] https://docs.google.com/document/d/1UyjTZuPFWiPFyKk1tV5an11_iaRuec6U-ZESZ54nNTY

Signed-off-by: Andrii Nakryiko 
Signed-off-by: Alexei Starovoitov 
Acked-by: John Fastabend 
Acked-by: Toke Høiland-Jørgensen 
Link: https://lore.kernel.org/bpf/20210525035935.1461796-4-andrii@kernel.org

bpf: Extend libbpf with bpf_map_lookup_and_delete_elem_flags

2021-05-24T20:30:51+00:00

Add bpf_map_lookup_and_delete_elem_flags() libbpf API in order to use
the BPF_F_LOCK flag with the map_lookup_and_delete_elem() function.

Signed-off-by: Denis Salopek 
Signed-off-by: Andrii Nakryiko 
Acked-by: Yonghong Song 
Link: https://lore.kernel.org/bpf/15b05dafe46c7e0750d110f233977372029d1f62.1620763117.git.denis.salopek@sartura.hr

libbpf: Support attachment of BPF tracing programs to kernel modules

2020-12-04T01:38:21+00:00

Teach libbpf to search for BTF types in kernel modules for tracing BPF
programs. This allows attachment of raw_tp/fentry/fexit/fmod_ret/etc BPF
program types to tracepoints and functions in kernel modules.

Signed-off-by: Andrii Nakryiko 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/20201203204634.1325171-13-andrii@kernel.org

libbpf: Factor out low-level BPF program loading helper

2020-12-04T01:38:21+00:00

Refactor low-level API for BPF program loading to not rely on public API
types. This allows painless extension without constant efforts to cleverly not
break backwards compatibility.

Signed-off-by: Andrii Nakryiko 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/20201203204634.1325171-12-andrii@kernel.org

libbpf: Cap retries in sys_bpf_prog_load

2020-12-03T20:01:18+00:00

I've seen a situation, where a process that's under pprof constantly
generates SIGPROF which prevents program loading indefinitely.
The right thing to do probably is to disable signals in the upper
layers while loading, but it still would be nice to get some error from
libbpf instead of an endless loop.

Let's add some small retry limit to the program loading:
try loading the program 5 (arbitrary) times and give up.

v2:
* 10 -> 5 retires (Andrii Nakryiko)

Signed-off-by: Stanislav Fomichev 
Signed-off-by: Andrii Nakryiko 
Acked-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20201202231332.3923644-1-sdf@google.com

libbpf: Add support for freplace attachment in bpf_link_create

2020-09-29T20:09:24+00:00

This adds support for supplying a target btf ID for the bpf_link_create()
operation, and adds a new bpf_program__attach_freplace() high-level API for
attaching freplace functions with a target.

Signed-off-by: Toke Høiland-Jørgensen 
Signed-off-by: Alexei Starovoitov 
Acked-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/160138355387.48470.18026176785351166890.stgit@toke.dk

libbpf: Remove assumption of single contiguous memory for BTF data

2020-09-29T00:27:31+00:00

Refactor internals of struct btf to remove assumptions that BTF header, type
data, and string data are layed out contiguously in a memory in a single
memory allocation. Now we have three separate pointers pointing to the start
of each respective are: header, types, strings. In the next patches, these
pointers will be re-assigned to point to independently allocated memory areas,
if BTF needs to be modified.

Signed-off-by: Andrii Nakryiko 
Signed-off-by: Alexei Starovoitov 
Acked-by: John Fastabend 
Link: https://lore.kernel.org/bpf/20200926011357.2366158-3-andriin@fb.com

libbpf: Support test run of raw tracepoint programs

2020-09-28T19:52:36+00:00

Add bpf_prog_test_run_opts() with support of new fields in bpf_attr.test,
namely, flags and cpu. Also extend _opts operations to support outputs via
opts.

Signed-off-by: Song Liu 
Signed-off-by: Daniel Borkmann 
Acked-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20200925205432.1777-3-songliubraving@fb.com

libbpf: Add BPF_PROG_BIND_MAP syscall and use it on .rodata section

2020-09-16T01:28:27+00:00

The patch adds a simple wrapper bpf_prog_bind_map around the syscall.
When the libbpf tries to load a program, it will probe the kernel for
the support of this syscall and unconditionally bind .rodata section
to the program.

Signed-off-by: YiFei Zhu 
Signed-off-by: Stanislav Fomichev 
Signed-off-by: Alexei Starovoitov 
Cc: YiFei Zhu 
Link: https://lore.kernel.org/bpf/20200915234543.3220146-4-sdf@google.com

libbpf: Centralize poisoning and poison reallocarray()

2020-08-19T01:38:25+00:00

Most of libbpf source files already include libbpf_internal.h, so it's a good
place to centralize identifier poisoning. So move kernel integer type
poisoning there. And also add reallocarray to a poison list to prevent
accidental use of it. libbpf_reallocarray() should be used universally
instead.

Signed-off-by: Andrii Nakryiko 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/20200819013607.3607269-4-andriin@fb.com