Re: Draft 1.9c

["Greg J. Badros" <gjb cs washington edu>]

raster@rasterman.com writes:

> On 24 Nov, Greg J. Badros scribbled:
> ->  raster@rasterman.com writes:
> ->  
> ->  <snip>
> ->  
> ->  > actually there is alreayd a machine name property as part of icccm:
> ->  > WM_CLIENT_MACHINE(STRING) = "raster.su.valinux.com"
> ->  > 
> ->  > so u use this in combo with PID (which fills the missing link) and then
> ->  > the WM or taskbar or whatever can manage all apps that are onthe same
> ->  > machine - and even coudl spawn helper apps on the particular machine
> ->  > the app is running on (if it van do this) to try kill or whatevre its
> ->  > pid there... so as long as we have a machien name AND a PId -we're set
> ->  
> ->  We actually can do this for legacy applications via the
> ->  "scwm_set_pid_property.so" module that comes in
> ->  scwm/utilities/pidproperty.  Then you do:
> ->  
> ->  LD_PRELOAD=$exec_prefix/scwm_set_pid_property.so xlogo
> 
> oh scwm did an alpreload hack! DAMN! i was planning on doign that..
> didnt know.. cool.. i shodul check it out.. :) i wonder if its done as
> efficiently as it coudl be.. dunno.. need to read src.. this sia good
> call - i was planning on having an LD_PRELOAD AND a hacked Xlib too
> (replacement Xlib soi distributions coudl include it)
> 
> if a wm (or helper app) spawns the process it can add the LD_PRELOAD to
> the env (tho SUID apps wont work.. but thats a minefield on its own)
> 
> very good.. :) excellent.. :)

Glad you like it;  I thought it was pretty clever, but was surprised
when we (Toby Sargeant and I) pulled it off.  (Actually while down
under, in fact -- maybe it's something in the Australian air that
suggests the id).

WRT efficiency, we just do a little bit of extra work on XCreateWindow
and XCreateSimpleWindow calls before handing off to the real routine.
There's a small hit, but not noticeable, for sure.  Certainly your
feedback is appreciated.

> ->  and the xlogo window gets its SCWM_RUNNING_PID property set to be its
> ->  process id.   Scwm also provides a helper procedure, too:
> ->  
> ->  (window-pid WINDOW)
> ->  
> ->  The pid property stuff also lets you set another arbitrary Id which is
> ->  useful for reliably determining which execution of a process a popped-up 
> ->  window corresponds to.  (E.g., to be able to treat a single start of an
> ->  application differently in the window manager, w/o affecting its X
> ->  resource name or titlebar name).
> 
> well thsi can be done just by PID :) oh hold on.. hmm no actually if
> the spawnign spawns a process that spawns yet another process that
> spanws yet another process (ie scriptS) then we have isses.. yes an
> inherited evnironment variable set by the wm fo rthat "launch" that is
> then set on all widnows displayed by that app.. yes.. i see this use..
> perhaps it shoudl be in the spec (apps have to set a property ont he
> window thta is the contents of thsi variable (numeric) ie:
> _NET_INSTANCE_ID(CARDINAL)

Right.  It gets tricky in even simple cases of shell-scripts that wrap
starting a GUI tool.

I think these sorts of things should also be proposed to the XFree folks 
since support from them will make the legacy application issue go away
on their X servers (and perhaps commercial X servers will then follow).

Greg