Xdummy standalone and packaging

[Antoine Martin]

There are a number of issues that can only be solved by having a proper supported Xvfb server with modern extension support (randr, etc), ie: #1, #2 (and potentially others - ​original winswitch ticket)

Although this is not strictly an Xpra thing, and is unlikely to live in the this xpra source repository, it is best to record this somewhere.
There are number of tasks:

• create an xorg project based on xorg-server, but with the ability to specify absolute config paths and dummy defaults
• merge it upstream and/or package it
• add code to xpra so it will use randr to resize the virtual framebuffer to the exact screen dimension of the client (currently resizes to the nearest size bigger than the client's)

All the info should now be here: wiki/Xdummy]

[Antoine Martin]

Posted an ​RFC to the xorg list, includes pointers to ​some patches which can be used to generate a /usr/bin/Xdummy binary suitable for Xpra.

[Antoine Martin]

There are now binary packages available ​here (fedora, centos, debian, ubuntu)

To test that your Xorg supports the new non-root options, run:

wget http://xpra.org/src/Xdummy/xorg.conf
Xorg +extension GLX +extension RANDR +extension RENDER -logfile log -config ./xorg.conf :200

Note: you must ensure that Xorg is not suid.
On Fedora (and possibly others) this means that you have to copy the existing binary, ie:

sudo cp /usr/bin/Xorg /usr/local/bin/Xorg

[Antoine Martin]

You can help get this moving by testing the packages (or building from source with the patch) and providing "Tested-by:" tags for ​the latest patch, like ​this one

[Antoine Martin]

... or "Reviewed-by" tags like ​this one

Please help get this merge with a quick test (there are binary packages built - so it doesn't take long...)

[Antoine Martin]

The changes have been merged upstream in ​commit ead968a4300c0adeff89b9886e888b6d284c75cc
​xf86-video-dummy should be tagged before the next server release too, so we can then automatically enable Xdummy with a simple X server version test:

$ X -version 2>&1 | grep "X Server"
X.Org X Server 1.11.2

Starting with soon-to-be-released 1.12

[Antoine Martin]

xf86-video-dummy 0.3.5 ​has been released

[Antoine Martin]

For more information on Xdummy, see the top-level page: ​Xdummy

[Antoine Martin]

patches required for building Xdummy for centos 5.8

[Antoine Martin]

patches required for building Xdummy for centos 6.2

[Antoine Martin]

patches required for building Xdummy on Fedora

[Antoine Martin]

Added Xdummy packages for CentOS 5.8 and 6.2 ​here, the CentOS and Fedora specific patches are archived in this ticket. The Fedora binaries will no longer be updated since Fedora 17 is the current release and includes the patches already.

[Antoine Martin]

As of r1286 (+ fix in r1295), we install an xpra.conf with Xdummy support if the distro supports it (ie: if Xorg version is >= 1.12 and if the Xorg binary is not suid)

This works for recent Debian / Ubuntu but not for Fedora/CentOS as those ship with a suid /usr/bin/Xorg (no easy way around that - we cannot copy the binary from the specfile's post-install scripts as was done in r1256 and later reverted, as system updates would break our copy... and also it wouldn't get updated)

[Antoine Martin]

We could provide support for Xdummy on Fedora 17 (and others with suid-only binaries) by copying the /usr/bin/Xorg binary every time before we use it, something like /usr/bin/xpra_Xvfb:

#!/bin/bash
mkdir -p ~/.xpra
cp /usr/bin/Xorg ~/.xpra/Xorg
~/.xpra/Xorg "$@"

I have filed ​a bug with Fedora asking for a non-suid Xorg to be installed.

[Antoine Martin]

r1549 adds support for suid Xorg installations (Fedora, etc)

[Antoine Martin]

More Xdummy work now in #186

[redneb]

The solution of copying /usr/bin/Xorg does not work with gentoo because the executable is installed as -rws--x--x. If I'm not mistaken this is a common practice, ie to make root suid executables not readable by anybody else. Gentoo does it automatically for all such executables.

[Antoine Martin]

redneb: thanks, this was already discussed on the mailing list (see ​here) and the fix is in r1984: gentoo users just won't be able to use Xdummy until Xorg is either not suid or readable, sorry.

[Antoine Martin]

Looks like there may be some useful randr changes coming to Xvfb (maybe in Xorg 1.14?):
​bug #26391 and ​this patch

It will be a while before this is shipped in any distro though.

[Antoine Martin]

If you want to know more about Xdummy and how to configure it, see wiki/Xdummy

[Antoine Martin]

Follow up and related tickets: #601, #732, #728, #349, #56

[migration script]

this ticket has been moved to: ​https://github.com/Xpra-org/xpra/issues/10