Core Wayland window system code and protocol
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Bryce Harrington 76fe89ed53 tests: Fix FAIL in sanity-test (*timeout*) when Yama LSM enabled
This fixes a regression in the testsuite since c3653f7f, where four of
the timeout tests fail with "Timeouts suppressed" messages.

The timeouts are being suppressed because the testsuite is erroneously
detecting that a debugger is attached.  This detection mechanism
(adopted from libinput) uses ptrace to test if there is a debugger
parent process that can be attached.  Unfortunately, this is an
unreliable test: Kernel security policies exist to restrict the scope of
ptrace to prevent processes from snooping on one another.[1] This
security policy is set as the default on Ubuntu, and potentially other
Linux distributions.[2]

The Yama documentation suggests, "For software that has defined
application-specific relationships between a debugging process and its
inferior (crash handlers, etc), prctl(PR_SET_PTRACER, pid, ...) can be
used.  An inferior can declare which other process (and its descendents)
are allowed to call PTRACE_ATTACH against it."  This prctl call has no
effect if Yama LSM is not loaded.

The child needs to be synchronized to the client to prevent a race
condition where the child might try to operate before the parent has
finished its prctl call.  This synchronization is done via pipes.

This patch can be tested by running sanity-test with
/proc/sys/kernel/yama/ptrace_scope set to 0 or 1; the test must pass for
either value.

1: http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=2d514487faf188938a4ee4fb3464eeecfbdcf8eb
2: https://wiki.ubuntu.com/SecurityTeam/Roadmap/KernelHardening#ptrace_Protection

Signed-off-by: Bryce Harrington <bryce@osg.samsung.com>
Reviewed-by: Marek Chalupa <mchqwerty@gmail.com>
Reviewed-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Derek Foreman <derekf@osg.samsung.com>

v4: Allow parent to communicate error state to child to prevent leaving
child in zombie state if parent hits an error.

v5: Check errno instead of rc for error.  Don't waitpid on ppid.
Signed-off-by: Bryce Harrington <bryce@osg.samsung.com>
2015-02-06 14:39:36 -08:00
cursor Add error handling for wl_cursors 2014-04-01 16:47:04 -07:00
doc doc: Fill in high level description for Surfaces 2015-02-04 21:49:30 -08:00
m4 Clean up .gitignore files 2010-11-11 20:11:27 -05:00
protocol protocol: Clarify selection data offer destruction requirement 2015-01-23 18:20:35 -08:00
spec doc: move documentation from the tex file to docbook 2012-03-28 23:04:25 -04:00
src event-loop: Dispatch idle callbacks twice 2015-01-28 18:12:31 -08:00
tests tests: Fix FAIL in sanity-test (*timeout*) when Yama LSM enabled 2015-02-06 14:39:36 -08:00
.gitignore gitignore: Add the new cpp-compile-test 2015-01-29 17:25:16 -08:00
autogen.sh Update autotools configuration 2010-11-06 21:04:03 -04:00
configure.ac configure.ac: re-bump version to 1.6.92 for rc1 release 2015-01-30 19:08:22 -08:00
COPYING Add COPYING 2012-04-25 10:12:21 -04:00
Makefile.am configure.ac: use pkg-config to find expat 2015-01-28 21:29:10 -08:00
README README: Tiny cosmetic change 2014-10-08 12:20:17 +01:00
TODO Update TODO 2012-10-21 20:53:37 -04:00
wayland-scanner.m4 scanner: check for wayland-scanner.pc before using variables 2013-08-07 16:25:10 -07:00
wayland-scanner.mk Split into a core repository that only holds the core Wayland libraries 2011-02-14 22:21:13 -05:00

What is Wayland?

Wayland is a project to define a protocol for a compositor to talk to
its clients as well as a library implementation of the protocol.  The
compositor can be a standalone display server running on Linux kernel
modesetting and evdev input devices, an X application, or a wayland
client itself.  The clients can be traditional applications, X servers
(rootless or fullscreen) or other display servers.

The wayland protocol is essentially only about input handling and
buffer management.  The compositor receives input events and forwards
them to the relevant client.  The clients creates buffers and renders
into them and notifies the compositor when it needs to redraw.  The
protocol also handles drag and drop, selections, window management and
other interactions that must go through the compositor.  However, the
protocol does not handle rendering, which is one of the features that
makes wayland so simple.  All clients are expected to handle rendering
themselves, typically through cairo or OpenGL.

The weston compositor is a reference implementation of a wayland
compositor and the weston repository also includes a few example
clients.

Building the wayland libraries is fairly simple, aside from libffi,
they don't have many dependencies:

    $ git clone git://anongit.freedesktop.org/wayland/wayland
    $ cd wayland
    $ ./autogen.sh --prefix=PREFIX
    $ make
    $ make install

where PREFIX is where you want to install the libraries.  See
http://wayland.freedesktop.org for more complete build instructions
for wayland, weston, xwayland and various toolkits.