[RESEND][PATCH 0/6] Add _opts variant for bpf_*_get_fd_by_id()

[Roberto Sassu <roberto.sassu@huaweicloud.com>]

From: Roberto Sassu <roberto.sassu@huawei.com>

NOTE: resending with libbpf_get_fd_opts test added to deny list for s390x.

Add the _opts variant for bpf_*_get_fd_by_id() functions, to be able to
pass to the kernel more options, when requesting a fd of an eBPF object to
the kernel.

Pass the options through a newly introduced structure, bpf_get_fd_opts,
which currently contains open_flags (the other two members are for
compatibility and for padding).

open_flags allows the caller to request specific permissions to access a
map (e.g. read-only). This is useful for example in the situation where a
map is write-protected.

Besides patches 2-6, which introduce the new variants and the data
structure, patch 1 fixes the LIBBPF_1.0.0 declaration in libbpf.map.

Roberto Sassu (6):
  libbpf: Fix LIBBPF_1.0.0 declaration in libbpf.map
  libbpf: Define bpf_get_fd_opts and introduce
    bpf_map_get_fd_by_id_opts()
  libbpf: Introduce bpf_prog_get_fd_by_id_opts()
  libbpf: Introduce bpf_btf_get_fd_by_id_opts()
  libbpf: Introduce bpf_link_get_fd_by_id_opts()
  selftests/bpf: Add tests for _opts variants of bpf_*_get_fd_by_id()

 tools/lib/bpf/bpf.c                           | 47 +++++++++-
 tools/lib/bpf/bpf.h                           | 16 ++++
 tools/lib/bpf/libbpf.map                      |  6 +-
 tools/testing/selftests/bpf/DENYLIST.s390x    |  1 +
 .../bpf/prog_tests/libbpf_get_fd_opts.c       | 88 +++++++++++++++++++
 .../bpf/progs/test_libbpf_get_fd_opts.c       | 36 ++++++++
 6 files changed, 189 insertions(+), 5 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/libbpf_get_fd_opts.c
 create mode 100644 tools/testing/selftests/bpf/progs/test_libbpf_get_fd_opts.c

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2.25.1