... 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glob() results might be out of date by the time we look at each file, just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.

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.

I suppose if we only had messages with no body text, this value could be 0
(not accounting for any headers) and thus throw a client off.

So consider this as part of the fix for issue #822.

For messages that have no body, we'd report 0. But RFC 1939 says this value
is supposed to be "the exact size of the message in octets" <sigh>. This
would include header fields, so while we can't know the exact RFC822 size,
adding the msg's hdr.length to these values gives size > 0 for messages
with no body text and this enables the Apple iPhone Mail app to download
the message (fixing issue #822).

Part two of this fix is to provide a blank line of message text when there
is none. This changes the message displayed in the iPhone Mail app from:

"This message cannot be displayed because of the way it is formatted.
 Ask the sender to send it again using a different format or email program.

 text/plain"

to (the much nicer):
 "This message has no content".

With the incremental backoffs, these were super long waits for locks. Not sure
about my math there, but at 500, the total timeout was not "about 45 seconds"
but rather several minutes.

At 100, the total max retry time should be almost exactly 45 seconds:

Retries      ms-per     total seconds
  0 - 9      0          0
 10 - 19     100        1
 20 - 29     200        3
 30 - 39     300        6
 40 - 49     400        10
 50 - 59     500        15
 60 - 69     600        21
 70 - 79     700        28
 80 - 89     800        36
 90 - 99     900        45*
100 - 109    1000       55
110 - 119    1100       66
120 - 129    1200       78
130 - 139    1300       91
140 - 149    1400       105
150 - 159    1500       120
160 - 169    1600       136
170 - 179    1700       153
180 - 189    1800       171
190 - 200    1900       200!

... so yeah, 500 was way too big a number.

Similar to what I do with user.tab record locks 2 months ago, this will
extend the total shared/network file open attempt duration from about 5
seconds to about 45 seconds, but with incrementing back-off.

Trying to sbbs-Linux to run from a Samba share without file open/locking
errors.

Re-synced the sbbs_t version of nopen with the nopen.c version (wasn't
special-handling EDEADLOCK failures).

Mostly we're using fnopen() these days anyway, which doesn't have an sbbs_t
version (for logging warning messages about collisions), perhaps it should.