[tor-bugs] #32910 [Core Tor/Tor]: trace: Add tracepoints and userspace tracer support

[Tor Bug Tracker & Wiki]

#32910: trace: Add tracepoints and userspace tracer support
--------------------------+------------------------------------
 Reporter:  dgoulet       |          Owner:  dgoulet
     Type:  enhancement   |         Status:  needs_revision
 Priority:  Medium        |      Milestone:  Tor: 0.4.4.x-final
Component:  Core Tor/Tor  |        Version:
 Severity:  Normal        |     Resolution:
 Keywords:  tracing       |  Actual Points:
Parent ID:                |         Points:  3
 Reviewer:  nickm         |        Sponsor:
--------------------------+------------------------------------

Comment (by dgoulet):

 So CI is only failing because of an issue with `make check-spaces`:

 {{{
      GUARD:./src/core/or/trace_probes_circuit.h:19: Header guard macro
 mismatch.
 }}}

 The reason for this is because of the unusual guard macro that LTTng-UST
 requires:

 {{{
 #if !defined(TOR_TRACE_PROBES_CIRCUIT_H) ||
 defined(TRACEPOINT_HEADER_MULTI_READ)
 #define TOR_TRACE_PROBES_CIRCUIT_H
 }}}

 I think we need to tell `checkSpace.pl` to allow the `#if !defined(` style
 and not only the `#ifndef`.

 This specific macro style is required because LTTng-UST, for internal
 probes creation, re-include multiple time the header file and thus
 overrides it with `TRACEPOINT_HEADER_MULTI_READ`.

 I've tried to patch `./scripts/maint/checkSpace.pl` to accept it but I'm
 unable to make it work... my perl skills are very poor. Nickm, advice?

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/32910#comment:8>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online