bpf: bpf_(prog|map|attach)_type_(from|to)_str helpers

Standardize commonly used bpf enum names by introducing helper methods to libbpf.
When applications require enum to string mapping the related code is copy-pasted from bpftool. It hardens maintenance, e.g. when new enum values are added.

Patches 0001-0003 introduce __MAX_BPF_PROG_TYPE and __MAX_BPF_MAP_TYPE enum type.
Patches 0004-0006 introduce helpers methods libbpf_str_from_(prog|map|attach)_type and libbpf_(prog|map|attach)_type_from_str.
Patches 0007-0008 extend and rename test_section_names test. Patches 0009-0010 introduce the helpers to bpftool.

An alternative for adding __MAX_BPF_(PROG|MAP)_TYPE is using an erroneous result of bpf_(prog|map|attach)_type_(from|to)_str as an indicator of loop bound. The disadvantages are: tests won't fail when a string name is not provided for a new enum value; whoever wants to loop over enum values should be aware about this side feature of newly introduced helpers.

Julia Kartseva (10):
bpf: introduce __MAX_BPF_PROG_TYPE and __MAX_BPF_MAP_TYPE enum values tools/bpf: sync bpf.h to tools/
tools/bpf: handle __MAX_BPF_(PROG|MAP)_TYPE in switch statements tools/bpf: add libbpf_prog_type_(from|to)_str helpers tools/bpf: add libbpf_map_type_(from|to)_str helpers tools/bpf: add libbpf_attach_type_(from|to)_str selftests/bpf: extend test_section_names with type_(from|to)_str selftests/bpf: rename test_section_names to
test_section_and_type_names
tools/bpftool: use libbpf_(prog|map)_type_to_str helpers tools/bpftool: use libbpf_attach_type_to_str helper

 include/uapi/linux/bpf.h                      |   6 +
 tools/bpf/bpftool/cgroup.c                    |  60 +--
 tools/bpf/bpftool/feature.c                   |  47 ++-
 tools/bpf/bpftool/main.h                      |  33 --
 tools/bpf/bpftool/map.c                       |  80 +---
 tools/bpf/bpftool/prog.c                      |  31 +-
 tools/include/uapi/linux/bpf.h                |   6 +
 tools/lib/bpf/libbpf.c                        | 153 +++++++
 tools/lib/bpf/libbpf.h                        |  17 +
 tools/lib/bpf/libbpf.map                      |   6 +
 tools/lib/bpf/libbpf_probes.c                 |   2 +
 tools/testing/selftests/bpf/Makefile          |   2 +-
 .../bpf/test_section_and_type_names.c         | 378 ++++++++++++++++++
 .../selftests/bpf/test_section_names.c        | 233 -----------
 14 files changed, 673 insertions(+), 381 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/test_section_and_type_names.c
 delete mode 100644 tools/testing/selftests/bpf/test_section_names.c

2.17.1