Re: The logic behind user/system settings

[Dan Williams <dcbw redhat com>]

On Tue, 2010-03-16 at 07:04 +0300, Andrey Borzenkov wrote:
> On Tuesday 16 of March 2010 02:10:25 Dan Williams wrote:
> > On Sat, 2010-03-13 at 08:17 +0300, Andrey Borzenkov wrote:
> > > On Friday 12 of March 2010 02:51:33 Dan Williams wrote:
> > > > On Wed, 2010-03-10 at 07:04 +0300, Andrey Borzenkov wrote:
> > > > > On Wednesday 10 of March 2010 04:12:19 Dan Williams wrote:
> > > > > > As you've discovered, there are user-specific settings (which
> > > > > > are only available when that user is logged in) and
> > > > > > system-wide settings (which are available to all users *and*
> > > > > > before any user has logged in).  The problem you're hitting
> > > > > > is when there aren't any settings at all, like right after
> > > > > > an install.
> > > > > > 
> > > > > > So NetworkManager creates an internal "Auto XXXX" connection
> > > > > > that at least allows your system to get online if there are
> > > > > > any DHCP-configured ethernet devices on the system.  This is
> > > > > > a "system-wide" connection and should be available at boot
> > > > > > and before login.
> > > > > 
> > > > > Are they created by NM service or
> > > > > nm-connection-editor/nm-applet? Should they be present even if
> > > > > other, explicitly defined connections exist?
> > > > 
> > > > It is created by NM itself.  It's present only if no other
> > > > /system/ connections are defined that apply to that device.
> > > 
> > > How NM decides that /system/ connection applies to device? I always
> > > see two auto connections for wlan interface - "Auto Wireless" and
> > > "Auto $CURRENT_SSID" even though there are system connections with
> > > $CURRENT_SSID defined.
> > 
> > A connection can be applied to a device if it's compatible with that
> > device; that means that the connection isn't MAC-locked to a
> > different device, or the connection doesn't require encryption
> > capabilities that the device doesn't support (ie a WPA2/AES
> > connection cannot be used with an old Prism card that only does
> > TKIP), etc.
> > 
> > Is the "Auto Wireless" a system connection? 
> 
> Actually, now. "Available for all users" is unchecked and greyed out. I 
> also do not see these connections using cnetworkmanager. They appear to 
> be created by nm-connection-editor itself for *some* APs in

Ok, the fact that the box is grayed out means that either (1) PolicyKit
and/or ConsoleKit aren't correctly installed (unlikely), or (2) you
don't have a system-settings plugin installed which is capable of saving
connections.  Check your /etc/NetworkManager/nm-system-settings.conf
file to see what system settings plugins you have enabled.

If you have 'keyfile' enabled, look
in /etc/NetworkManager/system-connections/.

If you  have 'ifupdown' enabled, look in /etc/network/interfaces.

If you have 'ifcfg-rh' enabled, look for files
in /etc/sysconfig/network-scripts that start with "ifcfg-".

> ./src/applet-device-wifi.c:wireless_new_auto_connection()

Yes, the only two places new user connections are created are in the
applet, when you click on a scanned network for which there isn't an
existing connection, or in the connection editor when you click "New".

> I do not understand how APs are selected - n-c-e always shows exactly 
> two of them. One is my home AP; another has literal name 'Wireless', but 
> I do not see it in scan result.

The connection editor only shows connections that *soemthing* has
defined.  So it's either provided by some system settings plugin, or
it's been created in the applet.  The name "Wireless" seems to indicate
that it's a system connection, since the applet always names things
"Auto XXXX".  It could also have been created by a user manually through
the connection editor, but by default the connection editor names new
connections like "Wireless connection 1" and "Wireless connection 2".
So my guess is that this connection is a system connection provided by
one of your plugins.

Dan