[DTrace-devel] [PATCH v6 0/7] add support for stapsdt probes

[Alan Maguire]

As well as using dtrace -G to generate USDT probes, programs and
libraries may have added static probes via stapsdt ELF notes.
This series adds support for such probes.  Patch 1 prepares for
this support by adding counting to parsing of stapsdt probe args
(since they do not include an explicit arg count); Patch 2 adds
the support, while patches 3-7 add tests covering that support.

Changes since v5:

- update copy_args() to remove strlen() check on every iteration
  (Kris, patch 1)
- restrict to specific pid probing, removing wildcard support for
  now (Kris, patch 2)
- add support for semaphores for is-enabled like stapsdt probes
  (Kris, patch 2)
- add test for semaphore support (patch 7)

Changes since v4:

- fix up address computation to work for libraries and -fPIE
  binaries; add a test for the latter (Kris, patches 2,6)
- do mapfile, Paddr_to_map() lookups once for stapsdt probes
  (Kris, patch 2)

Changes since v3:

- merged with USDT ELF note changes; since these use the same
argument-parsing/access code, no need to add code for this now (patch 2)
- updated said ELF note parsing to count as well as parse arguments
since stapsdt probes do not provide an arg count (patch 1)
- added explicit stapsdt provider to reflect that stapsdt probes
are fundamentally different and do not auto-register for discovery
via ioctl (patch 2, Kris)
- added simple pid wildcarding support for /proc map parsing.

Changes since v2:

- updated terminology to distinguish stapsdt from USDT probes

Alan Maguire (7):
  usdt: have copy_args() count args while parsing them
  support stapsdt ELF-note-defined static probes
  selftests/usdt: add test for stapsdt note-defined probe firing, args
  selftests/usdt: add test for stapsdt notes in shared library
  selftests/usdt: add test covering different forms of stapsdt note args
  selftests/usdt: add test for stapsdt note-defined probe firing in
    -fPIE binary
  selftests/usdt: add is-enabled stapsdt tests using semaphores

 include/dtrace/pid.h                          |   2 +
 libdtrace/dt_pid.c                            | 284 ++++++++++
 libdtrace/dt_prov_uprobe.c                    |  72 ++-
 test/unittest/usdt/sdt_notes.h                | 504 ++++++++++++++++++
 test/unittest/usdt/tst.stapsdt-notes-args.r   |   2 +
 test/unittest/usdt/tst.stapsdt-notes-args.sh  |  50 ++
 .../usdt/tst.stapsdt-notes-isenabled.r        |  14 +
 .../usdt/tst.stapsdt-notes-isenabled.sh       | 151 ++++++
 test/unittest/usdt/tst.stapsdt-notes-lib.r    |  14 +
 test/unittest/usdt/tst.stapsdt-notes-lib.sh   | 145 +++++
 test/unittest/usdt/tst.stapsdt-notes-pie.sh   | 121 +++++
 test/unittest/usdt/tst.stapsdt-notes.r        |  14 +
 test/unittest/usdt/tst.stapsdt-notes.sh       | 121 +++++
 13 files changed, 1481 insertions(+), 13 deletions(-)
 create mode 100644 test/unittest/usdt/sdt_notes.h
 create mode 100644 test/unittest/usdt/tst.stapsdt-notes-args.r
 create mode 100755 test/unittest/usdt/tst.stapsdt-notes-args.sh
 create mode 100644 test/unittest/usdt/tst.stapsdt-notes-isenabled.r
 create mode 100755 test/unittest/usdt/tst.stapsdt-notes-isenabled.sh
 create mode 100644 test/unittest/usdt/tst.stapsdt-notes-lib.r
 create mode 100755 test/unittest/usdt/tst.stapsdt-notes-lib.sh
 create mode 100755 test/unittest/usdt/tst.stapsdt-notes-pie.sh
 create mode 100644 test/unittest/usdt/tst.stapsdt-notes.r
 create mode 100755 test/unittest/usdt/tst.stapsdt-notes.sh

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2.39.3