Support both defaults and mandatory system config files
This commit introduces support for optional basic system-wide
configuration of vncserver.
The format and syntax of /etc/tigervnc/vncserver* match
that of $HOME/.vnc/config exactly.
Allows /etc/tigervnc/vncserver-config-defaults as well as
/etc/tigervnc/vncserver-config-mandatory. The former is optional
and sets user-overrideable vncserver settings. The latter is
optional, but if it exists takes precedence over all user
$HOME/.vnc/config settings of the same setting name. In the
case where /etc/tigervnc/vncserver-config-mandatory overrides
a setting in $HOME/.vnc/config, the user will be warned that
it has happened.
WARNING: Settings in /etc/tigervnc/vncserver-config-mandatory
are easily subverted by passing args to vncserver on the CLI.
The man page indicates this warning.
This commit also introduces (should have been separate) examination
of all config file settings (not just @ARGV!) when determining
whether or not $HOME/.vnc/passwd needs to be created. That is,
if /etc/tigervnc/vncserver* or $HOME/.vnc/config indicate that
we are NOT using VNC-native authentication, then we don't need
a $HOME/.vnc/passwd created.
Code cleanup:
$xstartup was renamed $xstartupFile for consistency with other
"file" variable names.
For VNC-auth checking, to determine if $HOME/.vnc/passwd needed
creation, the 3-string check against lc($arg2) was in 2 places
and was changed to a simple grep against the new @vncAuthStrings
diff --git a/unix/vncserver.man b/unix/vncserver.man
index fd7e93a..9108683 100644
--- a/unix/vncserver.man
+++ b/unix/vncserver.man
@@ -147,6 +147,26 @@
started. If this file does not exist, then vncserver will create a default
xstartup script which attempts to launch your chosen window manager.
.TP
+/etc/tigervnc/vncserver-config-defaults
+The optional system-wide equivalent of $HOME/.vnc/config. If this file exists
+and defines options to be passed to Xvnc, they will be used as defaults for
+users. The user's $HOME/.vnc/config overrides settings configured in this file.
+The overall configuration file load order is: this file, $HOME/.vnc/config,
+and then /etc/tigervnc/vncserver-config-mandatory. None are required to exist.
+.TP
+/etc/tigervnc/vncserver-config-mandatory
+The optional system-wide equivalent of $HOME/.vnc/config. If this file exists
+and defines options to be passed to Xvnc, they will override any of the same
+options defined in a user's $HOME/.vnc/config. This file offers a mechanism
+to establish some basic form of system-wide policy. WARNING! There is
+nothing stopping users from constructing their own vncserver-like script
+that calls Xvnc directly to bypass any options defined in
+/etc/tigervnc/vncserver-config-mandatory. Likewise, any CLI arguments passed
+to vncserver will override ANY config file setting of the same name. The
+overall configuration file load order is:
+/etc/tigervnc/vncserver-config-defaults, $HOME/.vnc/config, and then this file.
+None are required to exist.
+.TP
$HOME/.vnc/config
An optional server config file wherein options to be passed to Xvnc are listed
to avoid hard-coding them to the physical invocation. List options in this file