log: Add module and subsystem identifiers to log

[jlucovsky]

Continuation of #6022

This changeset provides subsystem and module identifiers in the log when
the log format string contains "%S". By convention, the log format
surrounds "%S" with brackets.

The subsystem name is generally the same as the thread name. The module
name is derived from the source code module name and usually consists of
the first one or 2 segments of the name using the dash character as the
segment delimiter.

Issue 2497: redmine

Updates:

1. Clang-format fixups

Describe changes:
This PR adds a subsystem and module identifier to SCLog messages when the log format includes %S. Subsystem and module identifiers are intrinsic properties of threads and source code modules (respectively).

New threads are assigned a subsystem identifier when the thread is created; the identifier is a Thread-Local-Storage variable declared in util-debug.c; values are assigned to it as threads are created using SCSetSubsystem (a macro defined in util-debug.h).

Module identifiers are derived from the source code module emitting the log message. A new CPP define __SCFILENAME__ is assigned to _sc_module (util-debug.h) at compile time. Rust source module names are determined dynamically during the calls to the log function.

Subsystem and module identifiers are added to log messages when the format contains %S. The generated log message will substitute a tag built from

• The subsystem identifier. This corresponds to the calling thread which may be the Suricata main thread, or a subordinate thread for a task-specific function, e.g., RX#01.
• (Optional) The module identifier will be included if set (not all source modules will set one but most source modules have been modified to set one.)
  The constructed tag is of the form subsystem-id[:module-identifier] (the brackets surrounding the module-identifier indicate the module-identifier is optional and are not included in the output; output formatting is strictly controlled by the log format in effect).

Also, two travis related changes are included in this PR

1. Update Travis to use Xenial (16.04) rather than Trusty (14.04)
2. Update to display config.log when Travis build errors occur.

#suricata-verify-pr:
#suricata-verify-repo:
#suricata-verify-branch:
#suricata-update-pr:
#suricata-update-repo:
#suricata-update-branch:
#libhtp-pr:
#libhtp-repo:
#libhtp-branch:

[codecov]

Codecov Report

Merging #6023 (e87b822) into master (b05bd05) will decrease coverage by 0.00%.
The diff coverage is 73.84%.

@@            Coverage Diff             @@
##           master    #6023      +/-   ##
==========================================
- Coverage   76.91%   76.91%   -0.01%     
==========================================
  Files         612      612              
  Lines      187721   187795      +74     
==========================================
+ Hits       144391   144442      +51     
- Misses      43330    43353      +23     

Flag	Coverage Δ
fuzzcorpus	52.64% <46.09%> (+0.05%)	⬆️
suricata-verify	50.27% <75.21%> (-0.03%)	⬇️
unittests	63.20% <44.91%> (-0.02%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

[jlucovsky]

Continued in #6024