There are programs, e.g. curl, that check if a connection was
established successfully by looking at SO_ERROR. Pretend that
the getsockopt() call was executed to keep them happy. If they
try to use a broken connection, the other socket functions will
bail.
Previously, the Genode::Timer::curr_time always used the
Timer_session::elapsed_ms RPC as back end. Now, Genode::Timer reads
this remote time only in a periodic fashion independently from the calls
to Genode::Timer::curr_time. If now one calls Genode::Timer::curr_time,
the function takes the last read remote time value and adapts it using
the timestamp difference since the remote-time read. The conversion
factor from timestamps to time is estimated on every remote-time read
using the last read remote-time value and the timestamp difference since
the last remote time read.
This commit also re-works the timeout test. The test now has two stages.
In the first stage, it tests fast polling of the
Genode::Timer::curr_time. This stage checks the error between locally
interpolated and timer-driver time as well as wether the locally
interpolated time is monotone and sufficiently homogeneous. In the
second stage several periodic and one-shot timeouts are scheduled at
once. This stage checks if the timeouts trigger sufficiently precise.
This commit adds the new Kernel::time syscall to base-hw. The syscall is
solely used by the Genode::Timer on base-hw as substitute for the
timestamp. This is because on ARM, the timestamp function uses the ARM
performance counter that stops counting when the WFI (wait for
interrupt) instruction is active. This instruction, however is used by
the base-hw idle contexts that get active when no user thread needs to
be scheduled. Thus, the ARM performance counter is not a good choice for
time interpolation and we use the kernel internal time instead.
With this commit, the timeout library becomes a basic library. That means
that it is linked against the LDSO which then provides it to the program it
serves. Furthermore, you can't use the timeout library anymore without the
LDSO because through the kernel-dependent LDSO make-files we can achieve a
kernel-dependent timeout implementation.
This commit introduces a structured Duration type that shall successively
replace the use of Microseconds, Milliseconds, and integer types for duration
values.
Open issues:
* The timeout test fails on Raspberry PI because of precision errors in the
first stage. However, this does not render the framework unusable in general
on the RPI but merely is an issue when speaking of microseconds precision.
* If we run on ARM with another Kernel than HW the timestamp speed may
continuously vary from almost 0 up to CPU speed. The Timer, however,
only uses interpolation if the timestamp speed remained stable (12.5%
tolerance) for at least 3 observation periods. Currently, one period is
100ms, so its 300ms. As long as this is not the case,
Timer_session::elapsed_ms is called instead.
Anyway, it might happen that the CPU load was stable for some time so
interpolation becomes active and now the timestamp speed drops. In the
worst case, we would now have 100ms of slowed down time. The bad thing
about it would be, that this also affects the timeout of the period.
Thus, it might "freeze" the local time for more than 100ms.
On the other hand, if the timestamp speed suddenly raises after some
stable time, interpolated time can get too fast. This would shorten the
period but nonetheless may result in drifting away into the far future.
Now we would have the problem that we can't deliver the real time
anymore until it has caught up because the output of Timer::curr_time
shall be monotone. So, effectively local time might "freeze" again for
more than 100ms.
It would be a solution to not use the Trace::timestamp on ARM w/o HW but
a function whose return value causes the Timer to never use
interpolation because of its stability policy.
Fixes#2400
This patch reduces the number of exception types by facilitating
globally defined exceptions for common usage patterns shared by most
services. In particular, RPC functions that demand a session-resource
upgrade not longer reflect this condition via a session-specific
exception but via the 'Out_of_ram' or 'Out_of_caps' types.
Furthermore, the 'Parent::Service_denied', 'Parent::Unavailable',
'Root::Invalid_args', 'Root::Unavailable', 'Service::Invalid_args',
'Service::Unavailable', and 'Local_service::Factory::Denied' types have
been replaced by the single 'Service_denied' exception type defined in
'session/session.h'.
This consolidation eases the error handling (there are fewer exceptions
to handle), alleviates the need to convert exceptions along the
session-creation call chain, and avoids possible aliasing problems
(catching the wrong type with the same name but living in a different
scope).
This patch reworks the implementation of core's RAM service to make use
of the 'Session_object' and to remove the distinction between the
"metadata" quota and the managed RAM quota. With the new implementation,
the session implicitly allocates its metadata from its own account. So
there is not need to handle 'Out_of_metadata' and 'Quota_exceeded' via
different exceptions. Instead, the new version solely uses the
'Out_of_ram' exception.
Furthermore, the 'Allocator::Out_of_memory' exception has become an alias
for 'Out_of_ram', which simplifies the error handling.
Issue #2398
This patch replaces the former use of size_t with the use of the
'Ram_quota' type to improve type safety (in particular to avoid
accidentally mixing up RAM quotas with cap quotas).
Issue #2398
Ldso now does not automatically execute static constructors of the
binary and shared libraries the binary depends on. If static
construction is required (e.g., if a shared library with constructor is
used or a compilation unit contains global statics) the component needs
to execute the constructors explicitly in Component::construct() via
Genode::Env::exec_static_constructors().
In the case of libc components this is done by the libc startup code
(i.e., the Component::construct() implementation in the libc).
The loading of shared objects at runtime is not affected by this change
and constructors of those objects are executed immediately.
Fixes#2332
Due to rounding in the timeout calculation it may happen that the timeout
stored in ms becomes 0, but actually some time (us or ns) are left to wait.
With threads on various priorities (vbox) this may end up in endless loops.
Fixes#2311
To select a different keyboard layout than the default 'en_us', override the
'language_chargen' function in your run script (after including
qt5_common.inc):
proc language_chargen { } { return "de" }
where "de" refers to the character map file
'repos/os/src/server/input_filter/de.chargen'
Issue #2264
If 'close' does not call 'unlink' like 'shutdown', the Lxip_socket_dir
never gets destroyed and thus the socket server leaks resources like
RAM and ports.
Ref #2285
Our 'shutdown' implementation handles only the case that 'how' is 'RDWR'.
Thus, print an error and continue if a user calls it with another value.
Fixes#2285
If 'Libc::Kernel::resume:all()' is called from a non-main thread, send a
signal to unblock the main thread from 'wait_and_dispatch_one_signal()'.
Fixes#2283
Libc components cannot use regular calls to select() as this may suspend
their execution. In this case incoming RPCs will be deferred until
select() returns and the component returns to the entrypoint dispatch
loop. The Libc::Signal_handler solves this problem with a its select()
that either returns the currently ready file descriptors immediately or
calls the registered handler function during libc resume.
Now, the libc kernel supports to execute application code from all RPC
functions not only Component::construct(). This is enabled by the
Libc::with_libc() scope function.
This commit extends an easy-to-use mechanism to allow Genode component
code to enter/leave the libc application context. This is needed
whenever low-level component code (like signal handlers or RPC
functions) need to interact with potentially blocking libc I/O
functions.
Please note that this commit contains the API-level design only. The
actual context switching code 'execute_in_application_context' is
missing.
The socket file system can be configured in the "socket" attribute of
the libc config node like follows.
<vfs> <dir name="socket"> <fs/> </dir> </vfs>
<libc ... socket="/socket"/>
This configures the socket file system libc backend to access files in
"/socket" for socket operations.
This change introduces a Genode specific init function, which sets the
backend allocator used by jent_zalloc/zfree(). As consequence the
library can solely be used by native Genode components, direct libc
usage is not supported.
Fixes#2274.
The support has two parts. First, a VFS plugin now gets passed an
I/O-response handler callback on construction, which informs users of the
VFS that an I/O event occurred. This enables, for example, the libC to
check if blocking read can be completed. Further, the VFS file I/O
interface provides now functions for suspendable reads, i.e.,
queue_read() and complete_read().
This commit enables compile-time warnings displayed whenever a deprecated
API header is included, and adjusts the existing #include directives
accordingly.
Issue #1987
Parse ``<env key="..." value=".."/>`` nodes from the config ROM and
populate a list at the 'genode_envp' and 'environ' symbols.
Test script at run/libc_getenv.
Fix#2236
Libc::Env is the Genode::Env interface extended to cover access
to the XML content of the 'config' ROM and a VFS instance. This
deduplicates the burden of components to attain and manage
these resources.
Fix#2217
Ref #1987
This patch removes the component_entry_point library, which used to
proved a hook for the libc to intercept the call of the
'Component::construct' function. The mechansim has several shortcomings
(see the discussion in the associated issue) and was complex. So we
eventually discarded the approach in favor of the explicit handling of
the startup.
A regular Genode component provides a 'Component::construct' function,
which is determined by the dynamic linker via a symbol lookup.
For the time being, the dynamic linker falls back to looking up a 'main'
function if no 'Component::construct' function could be found.
The libc provides an implementation of 'Component::construct', which
sets up the libc's task handling and finally call the function
'Libc::Component::construct' from the context of the appllication task.
This function is expected to be provided by the libc-using application.
Consequently, Genode components that use the libc have to implement the
'Libc::Component::construct' function.
The new 'posix' library provides an implementation of
'Libc::Component::construct' that calls a main function. Hence, POSIX
programs that merely use the POSIX API merely have to add 'posix' to the
'LIBS' declaration in their 'target.mk' file. Their execution starts at
'main'.
Issue #2199
On a 64-bit system, enabling the OpenSSL NIST 64-bit optimization should
result in considerable speed improvements when using curves: NIST-P224,
NIST-P256, and NIST-P521. Additionally it avoids that Tor complains
about having an OpenSSL that lacks this feature.
Ref #2193
This patch adjusts the various users of the 'Child' API to the changes
on the account of the new non-blocking parent interface. It also removes
the use of the no-longer-available 'Connection::KEEP_OPEN' feature.
With the adjustment, we took the opportunity to redesign several
components to fit the non-blocking execution model much better, in
particular the demo applications.
Issue #2120
This feature is not compatible with the forthcoming nonblocking parent
interface. The patch removes the use of feature in all places except for
the components of the demo repository, which will under go a redesign
anyway.
Issue #2120
Issue #2165
- use the correct memory free functions on errors
- report packet submit errors
- rename 'Usb::Packet_descriptor::transfer.timeout' as
'Usb::Packet_descriptor::transfer.polling_interval'
Fixes#2135
* Supply Env to Input::Session_component
* Attach input event dataspace at Input::Client
* Process input events by lambda rather than pointer
* Supply Env and a label to Input::Connection
* Wm serves valid input_session to decorator
* Per-source signal handling at input_merger
* Base API update for dummy_input_drv, test_input
* Input API update for launcher, menu_view, terminal,
mupdf, sdl, seoul, virtualbox
Ref #1987
Besides adapting the components to the use of base/log.h, the patch
cleans up a few base headers, i.e., it removes unused includes from
root/component.h, specifically base/heap.h and
ram_session/ram_session.h. Hence, components that relied on the implicit
inclusion of those headers have to manually include those headers now.
While adjusting the log messages, I repeatedly stumbled over the problem
that printing char * arguments is ambiguous. It is unclear whether to
print the argument as pointer or null-terminated string. To overcome
this problem, the patch introduces a new type 'Cstring' that allows the
caller to express that the argument should be handled as null-terminated
string. As a nice side effect, with this type in place, the optional len
argument of the 'String' class could be removed. Instead of supplying a
pair of (char const *, size_t), the constructor accepts a 'Cstring'.
This, in turn, clears the way let the 'String' constructor use the new
output mechanism to assemble a string from multiple arguments (and
thereby getting rid of snprintf within Genode in the near future).
To enforce the explicit resolution of the char * ambiguity, the 'char *'
overload of the 'print' function is marked as deleted.
Issue #1987
The initial support reports TouchPointPressed, TouchPointMoved, and
TouchPointReleased for multiple touch points, but is currently only
tested with widgets not leveraging multi-touch events. In other words, I
made sure synthetic mouse events are generated properly when using touch
screens.
The static 'Thread::mystack()' function returns the stack boundaries of
the calling thread. It is useful when a thread uses a diffent stack than
the primary one.
Fixes#2037
When calling 'connect()' in nonblocking mode and the connection has been
established, don't call 'tcp_connect()' again, which would trigger an
assertion with the message 'tcp_connect: can only connect from state
CLOSED'.
Fixes#2039
- platform_drv announces a separate "Acpi" session
- platform_drv waits for ROM "system" to change state to "acpi_ready"
- acpica waits for "Acpi" announcement
- acpica uses the platform driver via "Acpi" to reconfigure PCI devices
- acpica changes "system" state to "acpi_ready" after it ready with initialization
- platform_drv reacts on "system" state change to "acpi_ready" by announcing "Platform" session
- drivers start to operate as usual
Issue #2009
This patch introduces the Genode::raw function that prints output
directly via a low-level kernel mechanism, if available.
On base-linux, it replaces the former 'raw_write_str' function.
On base-hw, it replaces the former kernel/log.h interface.
Fixes#2012
Replace 'attribute(...).has_value("yes")`
with 'attribute_value(..., false)'.
This allows for boolean configuration to be set with values such as
"true", "false", "yes", "no", or "1", "0".
Fixes#2002
Allocating a packet in the packet stream without a payload is not
allowed. Therefore we have to allocate CTRL message packets, that do
not have a payload, with a bogus length instead.
It turns out that the name function does not have much use in practice
except for naming the thread of the component's initial entrypoint. For
dynamically linked components, this thread is created by the dynamic
linker. It is named "ep" in these cases. Considering that we will
eventually turn all regular components into dynamically linked
executables, the additional information provided by the
Component::name() function remains unused. So it is better to not bother
the component developers with adding boilerplate code.
Now rlibs are actually linked to programs. Target files have been
modified to not generate code that requires compiler-rt. Added a target
for libstd-rust, but it's very broken right now. Moved alloc_system to
the libports folder because either a memory allocator needs to be
written in rust or posix_memalign needs to be implemented. Changed
liblibc to use freebsd as the OS instead of netbsd. Added a library with
unwind dummy functions.
Rust relies on atomic builtins, which are not implemented in libgcc for
ARM. One was implemented in rust, which was sufficient to get the
current rust test to run. Rust libs were added into the group of libs
for the linker so order no longer matters. The raspberry pi now uses an
armv6 target.
This patch cleans up the thread API and comes with the following
noteworthy changes:
- Introduced Cpu_session::Weight type that replaces a formerly used
plain integer value to prevent the accidental mix-up of
arguments.
- The enum definition of Cpu_session::DEFAULT_WEIGHT moved to
Cpu_session::Weight::DEFAULT_WEIGHT
- New Thread constructor that takes a 'Env &' as first argument.
The original constructors are now marked as deprecated. For the
common use case where the default 'Weight' and 'Affinity' are
used, a shortcut is provided. In the long term, those two
constructors should be the only ones to remain.
- The former 'Thread<>' class template has been renamed to
'Thread_deprecated'.
- The former 'Thread_base' class is now called 'Thread'.
- The new 'name()' accessor returns the thread's name as 'Name'
object as centrally defined via 'Cpu_session::Name'. It is meant to
replace the old-fashioned 'name' method that takes a buffer and size
as arguments.
- Adaptation of the thread test to the new API
Issue #1954
This patch moves the base library from src/base to src/lib/base,
flattens the library-internal directory structure, and moves the common
parts of the library-description files to base/lib/mk/base.inc and
base/lib/mk/base-common.inc.
Furthermore, the patch fixes a few cosmetic issues (whitespace and
comments only) that I encountered while browsing the result.
Fixes#1952
The original 'Env' interface as returned by 'Genode::env()' has been
renamed to 'Env_deprecated' and moved to deprecated/env.h. The new version
of base/env.h contains the interface passed to modern components that
use the component API via base/component.h.
Issue #1832
This patch replaces the former 'Pd_session::bind_thread' function by a
PD-capability argument of the 'Cpu_session::create_thread' function, and
removes the ancient thread-start protocol via 'Rm_session::add_client' and
'Cpu_session::set_pager'. Threads are now bound to PDs at their creation
time and implicitly paged according to the address space of the PD.
Note the API change:
This patch changes the signature of the 'Child' and 'Process' constructors.
There is a new 'address_space' argument, which represents the region map
representing the child's address space. It is supplied separately to the
PD session capability (which principally can be invoked to obtain the
PD's address space) to allow the population of the address space
without relying on an 'Pd_session::address_space' RPC call.
Furthermore, a new (optional) env_pd argument allows the explicit
overriding of the PD capability handed out to the child as part of its
environment. It can be used to intercept the interaction of the child
with its PD session at core. This is used by Noux.
Issue #1938
This patch integrates three region maps into each PD session to
reduce the session overhead and to simplify the PD creation procedure.
Please refer to the issue cited below for an elaborative discussion.
Note the API change:
With this patch, the semantics of core's RM service have changed. Now,
the service is merely a tool for creating and destroying managed
dataspaces, which are rarely needed. Regular components no longer need a
RM session. For this reason, the corresponding argument for the
'Process' and 'Child' constructors has been removed.
The former interface of the 'Rm_session' is not named 'Region_map'. As a
minor refinement, the 'Fault_type' enum values are now part of the
'Region_map::State' struct.
Issue #1938
This patch prevents the destruction of the fd allocator when the program
exists. Otherwise, the meta data for file descriptors that were not
manually closed would vanish, which may cause problems in subsequent
destructors.
Opening a VFS handle previously involved allocating from the global heap
at each VFS file system. By amending open with an allocator argument,
dynamic allocation can be partitioned.
A new close method is used to deallocate open handles.
Issue #1751
Issue #1891
This commit introduces the new `Component` interface in the form of the
headers base/component.h and base/entrypoint.h. The os/server.h API
has become merely a compatibilty wrapper and will eventually be removed.
The same holds true for os/signal_rpc_dispatcher.h. The mechanism has
moved to base/signal.h and is now called 'Signal_handler'.
Since the patch shuffles headers around, please do a 'make clean' in the
build directory.
Issue #1832
This patch moves details about the stack allocation and organization
the base-internal headers. Thereby, I replaced the notion of "thread
contexts" by "stacks" as this term is much more intuitive. The fact that
we place thread-specific information at the bottom of the stack is not
worth introducing new terminology.
Issue #1832
Instead of using the 'alloc()' method to allocate new packets use
the 'next()' method with the previous packet. This is needed because
the last audio stack changes broke the semantics assumed by 'alloc()'.
We now keep track of the already queued packets by hand.
Fixes#1827.
Former Native_config::context_area_virtual_base() was used to identify
the main, which is not desired as the Native_config is rather low-level
(almost private to the base libs). The commit uses a library constructor
to retrieve the main-thread Thread_base pointer, which can be used later
to distinguish main and other threads.
The pthread object for the main thread initializes its 'Thread_base' base
class part with a reference to the 'Thread_base' object of the Genode main
thread. Therefore the pthread object for the main thread should never be
destroyed, as this would also destroy the Genode 'Thread_base' object.
Fixes#1760
Defer destruction of threads which tries to self-destruct. Check an perform
cleanup of such threads during pthread_cancel and pthread_create.
Issue #1687
The 'O_NONBLOCK' flag has different numerical values in lwip and in the
libc, which prevented the correct setting of nonblocking socket mode.
Fixes#1699
Instead of holding SPEC-variable dependent files and directories inline
within the repository structure, move them into 'spec' subdirectories
at the corresponding levels, e.g.:
repos/base/include/spec
repos/base/mk/spec
repos/base/lib/mk/spec
repos/base/src/core/spec
...
Moreover, this commit removes the 'platform' directories. That term was
used in an overloaded sense. All SPEC-relative 'platform' directories are
now named 'spec'. Other files, like for instance those related to the
kernel/architecture specific startup library, where moved from 'platform'
directories to explicit, more meaningful places like e.g.: 'src/lib/startup'.
Fix#1673
Run script depending on VFS plugins (i.e., shared objects) like
vfs_jitterentropy.lib.so have to state this dependency rather the actual
binaries linked against libc. The latter introduces a library dependency
that is just not there. For example, the dependency on vfs_jitterentropy
is a result from the config node for libc which automatically loads the
plugin.
Move FS Node implementations from server/ram_fs to include/ram_fs.
Support embedded ram_fs instances in VFS configurations using <ram/>.
Add 'no space' handling to VFS symlink ops.
Fixes#1635
SDL uses the Audio_out session in streaming fashion. For this reason
the audio might be played with delay of at most the queue size. To
mitigate the effect we synchronize the tail pointer to the current play
pointer when the PlayAudio() function is called by SDL for the first
time.
Fixes#1612.
This patch moves the VFS file-system factory to a separate vfs library
that is independent from libc. This enables libc-less Genode programs to
easily use the VFS infrastructure.
Fixes#1561
Physical CPU quota was previously given to a thread on construction only
by directly specifying a percentage of the quota of the according CPU
session. Now, a new thread is given a weighting that can be any value.
The physical counter-value of such a weighting depends on the weightings
of the other threads at the CPU session. Thus, the physical quota of all
threads of a CPU session must be updated when a weighting is added or
removed. This is each time the session creates or destroys a thread.
This commit also adapts the "cpu_quota" test in base-hw accordingly.
Ref #1464
This patch adds const qualifiers to the functions Allocator::consumed,
Allocator::overhead, Allocator::avail, and Range_allocator::valid_addr.
Fixes#1481
There are lots of places where a numeric argument of an argument string
gets extraced as signed long value and then assigned to an unsigned long
variable. If the value in the string was negative, it would not be
detected as invalid (and replaced by the default value), but become a
positive bogus value.
With this patch, numeric values which are supposed to be unsigned get
extracted with the 'ulong_value()' function, which returns the default
value for negative numbers.
Fixes#1472
With this patch, when calling 'setFocus()' on a QNitpickerViewWidget, the
Nitpicker view gets the input focus (provided that the parent Qt window
already had it).
Fixes#1314
In the init configuration one can configure the donation of CPU time via
'resource' tags that have the attribute 'name' set to "CPU" and the
attribute 'quantum' set to the percentage of CPU quota that init shall
donate. The pattern is the same as when donating RAM quota.
! <start name="test">
! <resource name="CPU" quantum="75"/>
! </start>
This would cause init to try donating 75% of its CPU quota to the child
"test". Init and core do not preserve CPU quota for their own
requirements by default as it is done with RAM quota.
The CPU quota that a process owns can be applied through the thread
constructor. The constructor has been enhanced by an argument that
indicates the percentage of the programs CPU quota that shall be granted
to the new thread. So 'Thread(33, "test")' would cause the backing CPU
session to try to grant 33% of the programs CPU quota to the thread
"test". By now, the CPU quota of a thread can't be altered after
construction. Constructing a thread with CPU quota 0 doesn't mean the
thread gets never scheduled but that the thread has no guaranty to receive
CPU time. Such threads have to live with excess CPU time.
Threads that already existed in the official repositories of Genode were
adapted in the way that they receive a quota of 0.
This commit also provides a run test 'cpu_quota' in base-hw (the only
kernel that applies the CPU-quota scheme currently). The test basically
runs three threads with different physical CPU quota. The threads simply
count for 30 seconds each and the test then checks wether the counter
values relate to the CPU-quota distribution.
fix#1275
The manpage to errno tells the following story:
The <errno.h> header file defines the integer variable errno, which is
set by system calls and some library functions in the event of an error
to indicate what went wrong. Its value is significant only when the
return value of the call indicated an error (i.e., -1 from most system
calls; -1 or NULL from most library functions); a function that
succeeds is allowed to change errno.
Valid error numbers are all nonzero; errno is never set to zero by any
system call or library function.
This commit adds a port the jitterentropy library to Genode. As
backend on x86_{32,64} 'rdtsc' is used and on ARMv{6,7} the
performance-counter.
Fixes#1239.
These file systems are provided on-demand by loading a shared library
when the fstab node is traversed. By convention this library is named
after the file system it provides. For example a file system that
provides a 'random' file system node is called 'vfs_random.lib.so'. It
is still possible to give the the node another name in the vfs. The
following code snippts illustrates this matter:
! [...]
! <config>
! <libc>
! <vfs>
! <dir name="dev"> <jitterentropy name="random"/> </dir>
! </vfs>
! </libc>
! </config>
! [...]
Here the jitterentropy file system, implemented in
'vfs_jitterentropy.lib.so' provides a file system node named 'random'
in the 'dev' directory. When traversing the vfs section the libc will
try to load 'vfs_jitterentropy.lib.so' but programs may access the
file system only via '/dev/random'.
Fixes#1240.
The QPluginWidget used to be a QNitpickerViewWidget but the new loader
interface does no longer hand out a view capability. So we need to
decouple both classes. This patch moves the view-geometry calculation to
a separate class to make it easier reusable, in particular for the
QPluginWidget.
This patch changes nitpicker's session interface to use session-local
view handles instead of view capabilities. This enables the batching
of multiple view operations into one atomic update.
For the correct integration of a QPluginWidget in a parent QWidget, with
this commit the parent QWidget's Nitpicker view is made the parent view of
the plugin's Nitpicker view.
Fixes#1173.
Now that it is possible to resize the stack of the Genode main thread, it
is not necessary anymore to create a new Genode thread as Qt main thread.
Fixes#1134.
This patch changes the top-level directory layout as a preparatory
step for improving the tools for managing 3rd-party source codes.
The rationale is described in the issue referenced below.
Issue #1082
