This patch replaces the former prominent use of pointers by references
wherever feasible. This has the following benefits:
* The contract between caller and callee becomes more obvious. When
passing a reference, the contract says that the argument cannot be
a null pointer. The caller is responsible to ensure that. Therefore,
the use of reference eliminates the need to add defensive null-pointer
checks at the callee site, which sometimes merely exist to be on the
safe side. The bottom line is that the code becomes easier to follow.
* Reference members must be initialized via an object initializer,
which promotes a programming style that avoids intermediate object-
construction states. Within core, there are still a few pointers
as member variables left though. E.g., caused by the late association
of 'Platform_thread' objects with their 'Platform_pd' objects.
* If no pointers are present as member variables, we don't need to
manually provide declarations of a private copy constructor and
an assignment operator to avoid -Weffc++ errors "class ... has
pointer data members [-Werror=effc++]".
This patch also changes a few system bindings on NOVA and Fiasco.OC,
e.g., the return value of the global 'cap_map' accessor has become a
reference. Hence, the patch touches a few places outside of core.
Fixes#3135
Since the timer and timeout handling is part of the base library (the
dynamic linker), it belongs to the base repository.
Besides moving the timer and its related infrastructure (alarm, timeout
libs, tests) to the base repository, this patch also moves the timer
from the 'drivers' subdirectory directly to 'src' and disamibuates the
timer's build locations for the various kernels. Otherwise the different
timer implementations could interfere with each other when using one
build directory with multiple kernels.
Note that this patch changes the include paths for the former os/timer,
os/alarm.h, os/duration.h, and os/timed_semaphore.h to base/.
Issue #3101
The pthread API is considered a standard feature of libc so better to
simply merge it with the libc. Pthreads are in fact already a part of
the libc in the form of weak symbols. This merger is also a prerequisite
for better integrating pthreads with the libc I/O task.
Fix#3054
The Arora main thread sometimes blocks on a pthread condition variable,
which prevents Genode signal processing with the current implementation.
This is especially a problem when the thread who could unblock the main
thread calls 'Libc::suspend()'.
As a workaround until the pthread locking mechanisms get adapted to the
Genode libc execution model, the Arora main function can be called from
a dedicated thread.
Fixes#2978
Close the stdin, stdout, and stderr I/O channels at child exit. This
serves to flush buffers at the I/O resources which might not be written
otherwise.
Ref #2919
