[RFC bpf-next 0/4] libbpf: userspace attach by name

[Alan Maguire <alan.maguire@oracle.com>]

This patch series is a rough attempt to support attach by name for
uprobes and USDT (Userland Static Defined Tracing) probes.
Currently attach for such probes is done by determining the offset
manually, so the aim is to try and mimic the simplicity of kprobe
attach, making use of uprobe opts.

One restriction applies: uprobe attach supports system-wide probing
by specifying "-1" for the pid.  That functionality is not supported,
since we need a running process to determine the base address to
subtract to get the uprobe-friendly offset.  There may be a way
to do this without a running process, so any suggestions would
be greatly appreciated.

There are probably a bunch of subtleties missing here; the aim
is to see if this is useful and if so hopefully we can refine
it to deal with more complex cases.  I tried to handle one case
that came to mind - weak library symbols - but there are probably
other issues when determining which address to use I haven't
thought of.

Alan Maguire (4):
  libbpf: support function name-based attach for uprobes
  libbpf: support usdt provider/probe name-based attach for uprobes
  selftests/bpf: add tests for u[ret]probe attach by name
  selftests/bpf: add test for USDT uprobe attach by name

 tools/lib/bpf/libbpf.c                             | 244 +++++++++++++++++++++
 tools/lib/bpf/libbpf.h                             |  17 +-
 tools/testing/selftests/bpf/Makefile               |  34 +++
 .../selftests/bpf/prog_tests/attach_probe.c        |  74 ++++++-
 .../selftests/bpf/progs/test_attach_probe.c        |  24 ++
 5 files changed, 391 insertions(+), 2 deletions(-)

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1.8.3.1