This appears to be the only way to 100% provide mutual exclusivity between
Windows and Linux client sharing a Samba file system.

Also, make fmutex_close() take a pointer to the file descriptor so that we can
better manage the resource (i.e. don't close a descriptor that's already been
closed and possibly valid in another thread).

... which simplifies the fmutex_close() function and signature.

By default, the duration is infinite, but some sysops may not want this
file to be ever-grower but rather periodically pruned by the new trashman
utility.

Sysop that don't use spambait.cfg won't benefit from this change.

Also, don't get hostname unless we're surely going to write to the file.

The 'atomic_remove' argument isn't used in non-Windows builds since we can
remove() before close() on non-Windows OSes already.

O_EXCL doesn't appear to be working very reliably over Samba, so let's add
file locking to the equation.

glob() results might be out of date by the time we look at each file, just
skip missing QWK pack semaphore files silently. This should resolve the
".now already gone" messages too. Hopefully.

Removed some extraneous quotes around logged event command-lines.

Also when detecting a blocked event_thread, log the event_code that is/was
running last.

This removes unnecessary some cruft and complexity, most especially from the
event_thread().

Using sbbs_t::fremove() instead of remove(). This probably resolves some
Coverity issues where we weren't checking the return value.

ENOENT = "No such file or directory"

Passing 'true' for the optional 'log_all_errors' parameter overrides this
(logs all errors, including ENOENT).

Add log message when spawning background timed event

Only log messages about QWK mutex files existing when > 60 seconds old

First, fix the logged username bug in the "Lock exists" log message.
Next, double check that the trigger file (sem file or REP file) still exists
after acquiring the file mutex.

Use a temp varible (fname) to make the code easier to read.

Vertrauen's FTP server gets abused by QWKnet logins sometimes and handling
the race conditions around QWK packet creation attempts is silly - there's
no legit reason why a QWKnet account needs to be logged-in multiple times
concurrently to the hub's FTP server, so reject the subsequent logins even
when they're on different hosts (as is the case with Vertrauen).

As part of this change:
- fmutex() now takes an new time_t* argument to (optionally) store the
  time of the mutex file for helping logging (locked since when?).
- time_as_hhmm() created to format a string as either HH:MM or HH:MM[a|p]
  (depending on system configuration for 12 or 24 hour time formatting).
- renamed the old hhmmtostr ()to tm_as_hhmm() (since it takes a struct tm arg)
  and have it return a non-padded string (useful in more situations without
  requiring truncation) when the sysop prefers 24-hour time.

Pretty remedial option parsing here, the order is significant

It looks like this has been a long-standing UIFC bug (pre-3.0)

If a uifc list that can scroll is showing the bottom-most line,
and an option that is not the last is deleted, and both *cur and
*bar are left untouched, *bar would be adjusted to be too high,
resulting in various highlight bar corruption issues.

This commit just rewrites that logic to be comprehensible, and
ensures that if bar is set such that the list would end before the
bottom of the window, it gets moved up.  This makes delete do the
right thing (didn't test with insert, that may do weird things).

Also, since I figured out a good definition of what bar actually
represtens, add a comment to that effect.

So you want to debug (timed) events, but don't want to get debug-spew in your
terminal server log output? Now you can: By default, the event thread log
level will be the same as the terminal server, but now you can override this
by setting [BBS] EventLogLevel in the sbbs.ini file or set it in
SCFG->Servers->Terminal Server->Event Log Level.

there are still other undocumented fields/properties, but this one for sure
was missing.

If the body of the request mesages message contains a list of area-tags,
even if we already have the node linked to those echoes, do the rescan for
each listed echo. Previously, only newly-added echoes would be rescanned
via this method.

Apparently the D'bridge built-in method of generating AreaManager requests
uses this syntax (per Ward Dossche).

Also, when rescanning due to AreaManager rescan request and generating a
response netmail message, include the total number of messages exported as a
result.

Increase SBBSecho version number to v3.22 (Please upgrade, Fernando) :-)

Configured in SCFG->External Programs->Fixed Events and the Node Daily Events
configured in SCFG->Nodes, now can be disabled (without just clearing the
command-line) and toggle-on "Native", so the program doesn't have to be added
to the dreaded "Native Program List" in order to *not* be treated as a 16-bit
DOS program (the default).

Eventually I'll allow multiple of each time of system fixed event, but this
is an improvement for now at least.

Likely fix for CID 514647

... also the support for multiple spaces or commas separating each filename.

Oh, FTS-1, how did I miss thee?

Previously, this feature assumed just one request per FREQ message, however
FTS-1 make this clear:

      If  one  or more  of FileAttached, FileRequest, or  FileUpdateReq  are
      asserted  in an AttributeWord, the subject{72} field is interpreted as
      a  list of file specifications  which may include wildcards and  other
      system-dependent data.  This list is of the form

      FileList = [ FileSpec { Sep FileSpec } ] Null

      FileSpec = (* implementation dependent file specification.  may
                    not contain Null or any of the characters in Sep. *)

      Sep      = ( " " | "," )  { " " }

Prefer sdl2-config from the path, and only use the framework in
/Library/Frameworks if that doesn't exist... to that end, don't
copy the framework into the app anymore unless you're using it.

This should clean out the pipes.

To replace lost the default/conio icon (for Windows builds) recently

When writing the attached file path/names to the FLO file, parse each
filename out of the subject, accordingly. This should fix issue #824.

There's an inconsistent support in SBBSecho for FileLists in the subjects of
netmail messages. In a couple of places, single-space-separated filelists are
fine (but not commas or multiple space, even though they are allowed per
FTS-1).

This particular fix is just for the packing of netmail messages and the
appending the attached file(s) to the FLO file. Those other places (e.g.
.REQ file creation) will need their own fixes for proper filelist support.

... to be sure configured newsgroup name is RFC compliant.

also retrying fread() and chsize(), but that seems harmless.

Note: EBUSY was added to the list of errno values that should cause a retry
as observed on Vertrauen, running sbbs-linux on a Samba mount, opening
locked files can return failure (-1) with errno = EBUSY, e.g.
evnt BBS Events !ERROR 16 (Device or resource busy) in logon.cpp line 616 (logonstats) reading "system stats" access=0

This was apparently resolved by adding EBUSY (16) the values that trigger an sopen()
retry (i.e. from [f]nopen()).