CVS commit: src/tests/lib/libc/sys

["Kamil Rytarowski" <kamil%netbsd.org@localhost>]

Module Name:    src
Committed By:   kamil
Date:           Tue May 29 10:40:54 UTC 2018

Modified Files:
        src/tests/lib/libc/sys: t_ptrace_wait.c

Log Message:
Add new ATF ptrace(2) tests verifying crash signal handling

Add new tests:
 - traceme_crash_trap
 - traceme_crash_segv
 - traceme_crash_ill (temporarily disabled)
 - traceme_crash_fpe
 - traceme_crash_bus
 - unrelated_tracer_sees_crash_trap
 - unrelated_tracer_sees_crash_segv
 - unrelated_tracer_sees_crash_ill (temporarily disabled)
 - unrelated_tracer_sees_crash_fpe
 - unrelated_tracer_sees_crash_bus

These tests verify two subtle kernel paths that differ internally:
 - for a tracer that is a parent of a traced program (and not vforked)
   real parent == tracer
 - for a tracer that is an unrelated process of a traced program
   real parent != tracer

Regressions in the signal code can cause to break one of the scenarios, and
keep working the other one. It might be propagated to a scenario like:
 - attaching to a process with a debugger (over pid)
 - starting a process inside a debugger

We can assert on the ATF level that both will be functional.

While there, cover all the crash signals as testing is done practically
for free. While the Machine Independent signal routing code for crash
signals is mostly the same in the kernel, we can verify whether Machine
Dependent parts works as expected emitting the proper signal number and
signal code (si_code).

There have been already caught an unexpected behavior on Alpha, that
instead of SIGBUS we receive SIGSEGV.

Another benefit is that it's easier to catch races, as they pop up more
frequently. (This already helped to catch bugs more quickly)

These tests will help assert correctness of future kernel changes in the
signal routines.

All tests pass.

Sponsored by <The NetBSD Foundation>


To generate a diff of this commit:
cvs rdiff -u -r1.58 -r1.59 src/tests/lib/libc/sys/t_ptrace_wait.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.