The server requires clients to only allocate one ID ahead of the previously
highest ID in order to keep the ID range tight. Failure to do so will
make the server close the client connection. However, the way we allocate
new IDs is racy. The generated code looks like:
new_proxy = wl_proxy_create(...);
wl_proxy_marshal(proxy, ... new_proxy, ...);
If two threads do this at the same time, there's a chance that thread A
will allocate a proxy, then get pre-empted by thread B which then allocates
a proxy and then passes it to wl_proxy_marshal(). The ID for thread As
proxy will be one higher that the currently highest ID, but the ID for
thread Bs proxy will be two higher. But since thread B prempted thread A
before it could send its new ID, B will send its new ID first, the server
will see the ID from thread Bs proxy first, and will reject it.
We fix this by introducing wl_proxy_marshal_constructor(). This
function is identical to wl_proxy_marshal(), except that it will
allocate a wl_proxy for NEW_ID arguments and send it, all under the
display mutex. By introducing a new function, we maintain backwards
compatibility with older code from the generator, and make sure that
the new generated code has an explicit dependency on a new enough
libwayland-client.so.
A virtual Wayland merit badge goes to Kalle Vahlman, who tracked this
down and analyzed the issue.
Reported-by: Kalle Vahlman <kalle.vahlman@movial.com>
Looking at the functionality in the server library, it's clear (in
hindsight) that there are two different "things" in there: 1) The IPC
API, that is, everything that concerns wl_display, wl_client,
wl_resource and 2) and half-hearted attempt at sharing input code and
focus logic that leaves a lot of problematic structs in the API
surface, only to share less than 1000 lines of code.
We can just move those input structs and helper functions into weston
and cut libwayland-server down to just the core server side IPC API.
In the short term, compositors can copy those structs and functions
into their source, but longer term, they're probably better off
reimplementing those objects and logic their native framework
(QObject, GObject etc).
'fixed' is a signed decimal type which offers a sign bit, 23 bits of
integer precision, and 8 bits of decimal precision. This is exposed as
an opaque struct with conversion helpers to and from double and int on
the C API side.
Signed-off-by: Daniel Stone <daniel@fooishbar.org>
Some system C libraries do not offer SOCK_CLOEXEC flag.
Add a new header for OS compatibility wrappers. Wrap socket() calls into
wl_os_socket_cloexec() which makes sure the O_CLOEXEC flag gets set on
the file descriptor.
On systems having SOCK_CLOEXEC this uses the old socket() call, and
falls back if it fails due to the flag (kernel not supporting it).
wayland-os.h is private and not exported.
Add close-on-exec tests for both normal and forced fallback paths.
Signed-off-by: Pekka Paalanen <ppaalanen@gmail.com>
This adds a public header so that applications can get the Wayland
version number at compile time. This can be used to make applications
that support compiling against multiple versions of Wayland.
There is a separate installed header called cogl-version.h which gets
included by both wayland-client.h and wayland-server.h
The canonical place for the version number is the configure.ac script
which splits it into three separate m4 defines for the major, minor
and micro version. These are copied into the generated
wayland-version.h header using AC_SUBST. There is also a string form
of the complete version number.
The version number is now also automatically copied into the two .pc
files.
Because the major, minor and micro parts are required it is no longer
possible to leave the version number as 'master' when building from
git. Most projects seem to immediately bump the git repo to a fake
version number (usually odd) after making a release so that there is
always a relative number that can be used for comparison. This patch
sets the git version to 0.99.0 under the assumption that the next
release will be 1.0.0.
