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[v4,bpf-next,0/4] tools/btf: extend libbpf APIs to work with btf w/o kernel

Message ID 20190208191939.3105592-1-andriin@fb.com
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Series tools/btf: extend libbpf APIs to work with btf w/o kernel | expand

Message

Andrii Nakryiko Feb. 8, 2019, 7:19 p.m. UTC 
This patchset introduces a set of new APIs that make it possible to work with BTF
more effectively (and without involving kernel) for applications like pahole that
need to manipulate .BTF and .BTF.ext data.

Patch #1 changes existing btf__new() API call to only load and initialize
struct btf, while exposing new btf__load() API to attempt to load and validate
BTF in kernel.

Patch #2 adds btf__get_raw_data() API allowing to get access to raw BTF data from
struct btf.

Patch #3 adds similar btf_ext__get_raw_data() API for working with struct btf_ext.

Patch #4 removes not-yet-stable btf__get_strings() API which was added to be able
to test contents of struct btf for btf__dedup(). It's now superseded by raw APIs.

v3->v4:
- formatting fixes
- renamed btf_ext functions/structs to use "setup" language instead of "copy"
- removed btf__get_strings from libbpf.map

v2->v3:
- const void* variants of btf__get_raw_data()
- added btf_ext__get_raw_data()
- removed btf__get_strings() and adapted test_btf.c to use btf__get_raw_data()

v1->v2:
- btf_load() returns just error, not fd
- fix ordering in libbpf.map

Andrii Nakryiko (4):
  btf: separate btf creation and loading
  btf: expose API to work with raw btf data
  btf: expose API to work with raw btf_ext data
  tools/bpf: remove btf__get_strings() superseded by raw data API

 tools/lib/bpf/btf.c                    | 163 +++++++++++++------------
 tools/lib/bpf/btf.h                    |   6 +-
 tools/lib/bpf/libbpf.c                 |   2 +-
 tools/lib/bpf/libbpf.map               |   4 +-
 tools/testing/selftests/bpf/test_btf.c |  39 ++++--
 5 files changed, 121 insertions(+), 93 deletions(-)

Comments

Alexei Starovoitov Feb. 8, 2019, 8:08 p.m. UTC | #1 
On Fri, Feb 08, 2019 at 11:19:35AM -0800, Andrii Nakryiko wrote:
> This patchset introduces a set of new APIs that make it possible to work with BTF
> more effectively (and without involving kernel) for applications like pahole that
> need to manipulate .BTF and .BTF.ext data.
> 
> Patch #1 changes existing btf__new() API call to only load and initialize
> struct btf, while exposing new btf__load() API to attempt to load and validate
> BTF in kernel.
> 
> Patch #2 adds btf__get_raw_data() API allowing to get access to raw BTF data from
> struct btf.
> 
> Patch #3 adds similar btf_ext__get_raw_data() API for working with struct btf_ext.
> 
> Patch #4 removes not-yet-stable btf__get_strings() API which was added to be able
> to test contents of struct btf for btf__dedup(). It's now superseded by raw APIs.
> 
> v3->v4:
> - formatting fixes
> - renamed btf_ext functions/structs to use "setup" language instead of "copy"
> - removed btf__get_strings from libbpf.map
> 
> v2->v3:
> - const void* variants of btf__get_raw_data()
> - added btf_ext__get_raw_data()
> - removed btf__get_strings() and adapted test_btf.c to use btf__get_raw_data()
> 
> v1->v2:
> - btf_load() returns just error, not fd
> - fix ordering in libbpf.map

Applied, Thanks