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From: Andrii Nakryiko <andriin@fb.com>
To: <bpf@vger.kernel.org>, <netdev@vger.kernel.org>, <ast@fb.com>,
	<daniel@iogearbox.net>
Cc: <andrii.nakryiko@gmail.com>, <kernel-team@fb.com>,
	Andrii Nakryiko <andriin@fb.com>
Subject: [PATCH v2 bpf-next 0/3] Add new-style bpf_object__open APIs
Date: Thu, 3 Oct 2019 22:32:32 -0700	[thread overview]
Message-ID: <20191004053235.2710592-1-andriin@fb.com> (raw)

Add bpf_object__open_file() and bpf_object__open_mem() APIs that use a new
approach to providing future-proof non-ABI-breaking API changes. It relies on
APIs accepting optional self-describing "opts" struct, containing its own
size, filled out and provided by potentially outdated (as well as
newer-than-libbpf) user application. A set of internal helper macros
(OPTS_VALID, OPTS_HAS, and OPTS_GET) streamline and simplify a graceful
handling forward and backward compatibility for user applications dynamically
linked against different versions of libbpf shared library.

Users of libbpf are provided with convenience macro LIBBPF_OPTS that takes
care of populating correct structure size and zero-initializes options struct,
which helps avoid obscure issues of unitialized padding. Uninitialized padding
in a struct might turn into garbage-populated new fields understood by future
versions of libbpf.

Patch #3 switches two of test_progs' tests to use new APIs as a validation
that they work as expected.

v1->v2:
- use better approach for tracking last field in opts struct;
- convert few tests to new APIs for validation;
- fix bug with using offsetof(last_field) instead of offsetofend(last_field).

Andrii Nakryiko (3):
  libbpf: stop enforcing kern_version, populate it for users
  libbpf: add bpf_object__open_{file,mem} w/ extensible opts
  selftests/bpf: switch tests to new bpf_object__open_{file,mem}() APIs

 tools/lib/bpf/libbpf.c                        | 128 +++++++++---------
 tools/lib/bpf/libbpf.h                        |  38 +++++-
 tools/lib/bpf/libbpf.map                      |   3 +
 tools/lib/bpf/libbpf_internal.h               |  32 +++++
 tools/testing/selftests/bpf/Makefile          |   2 +-
 .../selftests/bpf/prog_tests/attach_probe.c   |  42 +++++-
 .../bpf/prog_tests/reference_tracking.c       |   7 +-
 .../selftests/bpf/progs/test_attach_probe.c   |   1 -
 .../bpf/progs/test_get_stack_rawtp.c          |   1 -
 .../selftests/bpf/progs/test_perf_buffer.c    |   1 -
 .../selftests/bpf/progs/test_stacktrace_map.c |   1 -
 11 files changed, 176 insertions(+), 80 deletions(-)

-- 
2.17.1


             reply	other threads:[~2019-10-04  5:32 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-04  5:32 Andrii Nakryiko [this message]
2019-10-04  5:32 ` [PATCH v2 bpf-next 1/3] libbpf: stop enforcing kern_version, populate it for users Andrii Nakryiko
2019-10-04  5:32 ` [PATCH v2 bpf-next 2/3] libbpf: add bpf_object__open_{file,mem} w/ extensible opts Andrii Nakryiko
2019-10-04  6:38   ` Toke Høiland-Jørgensen
2019-10-04 15:29     ` Andrii Nakryiko
2019-10-04  5:32 ` [PATCH v2 bpf-next 3/3] selftests/bpf: switch tests to new bpf_object__open_{file,mem}() APIs Andrii Nakryiko

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