When specifying "/" or "" as rel_path to the 'Directory' constructor,
the constructed directory should refer to the same directory. The
implementation of the join utility did not consider this corner case. It
occurred during the attempt to use fs_query with "/" given as path.
This patch also adds a Directory::Entry::dir accessor that returns true
if the entry is a directory.
Fixes#3630
This patch adds a special variant of a 'Content_producer' called
'Xml_producer', which allows the direct use of an 'Xml_generator'
for generating the ROM-module content.
This patch extracts the child-management functionality from the init
component into a new library called "sandbox". The library API is
located at 'os/include/os/sandbox.h'.
The sandbox API allows for the interaction of the component with the
sandboxed children by providing locally implemented services. This
mechanism is illustrated by the new test at os/src/test/sandbox.
Issue #3601
This patch extends the 'Buffered_xml' utility with a new constructor
that fills the buffer with the output of an 'Xml_generator'. It thereby
presents an easy way to generate XML to be consumed locally.
The patch also add a deprecation mark to the original 'xml' accessor
because copying 'Xml_node' objects (here as return value) is dangerous.
The new 'with_xml_node' method should instead be used to access the XML
content stored in the buffer.
Fixes#3602
`volatile` effectively prevents instruction reordering by the compiler
and fixes an issue with -O3 compiled components.
Note, this commit does not address further arguments regarding memory
barriers and volatile voiced in issue #693.
Issue #693
This patch adds support for manually triggering the wakeup of the packet
sink by the source. This way, a packet source becomes able to marshal
batches of submissions or unmarshal batches of acknowledgements before
yielding the control over to the sink.
Issue #3283
The new 'transfer' function interface defines how pixel/alpha values
sampled from texture are applied to a destination pixel, similar to the
role of a fragment shader in GPU-based rendering. The transfer function
can be customized by defining custom pixel types, which may be (but
don't need to be) derived from 'Pixel_rgba'.
Issue #3221
This commit removes APIs that were previously marked as deprecated. This
change has the following implications:
- The use of the global 'env()' accessor is not possible anymore.
- Boolean accessor methods are no longer prefixed with 'is_'. E.g.,
instead of 'is_valid()', use 'valid()'.
- The last traces of 'Ram_session' are gone now. The 'Env::ram()'
accessor returns the 'Ram_allocator' interface, which is a subset of
the 'Pd_session' interface.
- All connection constructors need the 'Env' as argument.
- The 'Reporter' constructor needs an 'Env' argument now because the
reporter creates a report connection.
- The old overload 'Child_policy::resolve_session_request' that returned
a 'Service' does not exist anymore.
- The base/printf.h header has been removed, use base/log.h instead.
- The old notion of 'Signal_dispatcher' is gone. Use 'Signal_handler'.
- Transitional headers like os/server.h, cap_session/,
volatile_object.h, os/attached*_dataspace.h, signal_rpc_dispatcher.h
have been removed.
- The distinction between 'Thread_state' and 'Thread_state_base' does
not exist anymore.
- The header cpu_thread/capability.h along with the type definition of
'Cpu_thread_capability' has been removed. Use the type
'Thread_capability' define in cpu_session/cpu_session.h instead.
- Several XML utilities (i.e., at os/include/decorator) could be removed
because their functionality is nowadays covered by util/xml_node.h.
- The 'os/ram_session_guard.h' has been removed.
Use 'Constrained_ram_allocator' provided by base/ram_allocator.h instead.
Issue #1987
This patch enhances the packet-stream API with the principle ability to
side-step the built-in implicity data-flow signals and manage the
signals manually. This allows for a more efficient batching of packet
processing.
Issue #3092
The situation where a 'Session_policy' is constructed for a label with
no matching policy is in almost all cases a configuration problem.
A diagnostic message eases pin-pointing such mistaks. By adding the
message to the 'Session_policy', servers don't need to manually handle
the exception to provide diagnostic information. This simplifies the
server code in many components.
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
Packets whose data is stored within the Packet_descriptor itself
but not as payload, .e.g Usb::Packet_descriptor, are valid packets
after all. So loosen the packet valid check for zero-sized packets
is reasonable.
Fixes#3076.
Some application code is dereferencing the pointer returned by
'packet_content' at packet streams without checking that it is valid.
Throw an exception rather than return a null pointer, except for
zero-length packets, which have somewhat implicit invalid content and
that we believe to be properly handled in all current cases.
The client-side of a packet stream cannot take corrective action if the
server-side is sending packets with invalid content, but the servers
that provide packet streams should catch this exception to detect
misbehaving clients.
Ref #3059
The bulk buffer is now 64Byte-aligned so that the allocated
packets get aligned likewise (assumed the packet allocator uses an
appropriately aligned block size). This ensures that each packet
starts at a new cache line on common platforms.
Issue #3053
The 'Expanding_reporter' wrapper for the 'Reporter' eliminates
the burden of handling 'Xml_generator::Buffer_exceeded' exceptions
from components that generate reports.
Fixes#2655
The 'Buffered_xml' utility is used by three components and a fourth is
on the way. To avoid another duplication of the code, this patch makes
it publicly available at 'os/buffered_xml.h'.
The patch adjust the code of the base, base-<kernel>, and os repository.
To adapt existing components to fix violations of the best practices
suggested by "Effective C++" as reported by the -Weffc++ compiler
argument. The changes follow the patterns outlined below:
* A class with virtual functions can no longer publicly inherit base
classed without a vtable. The inherited object may either be moved
to a member variable, or inherited privately. The latter would be
used for classes that inherit 'List::Element' or 'Avl_node'. In order
to enable the 'List' and 'Avl_tree' to access the meta data, the
'List' must become a friend.
* Instead of adding a virtual destructor to abstract base classes,
we inherit the new 'Interface' class, which contains a virtual
destructor. This way, single-line abstract base classes can stay
as compact as they are now. The 'Interface' utility resides in
base/include/util/interface.h.
* With the new warnings enabled, all member variables must be explicitly
initialized. Basic types may be initialized with '='. All other types
are initialized with braces '{ ... }' or as class initializers. If
basic types and non-basic types appear in a row, it is nice to only
use the brace syntax (also for basic types) and align the braces.
* If a class contains pointers as members, it must now also provide a
copy constructor and assignment operator. In the most cases, one
would make them private, effectively disallowing the objects to be
copied. Unfortunately, this warning cannot be fixed be inheriting
our existing 'Noncopyable' class (the compiler fails to detect that
the inheriting class cannot be copied and still gives the error).
For now, we have to manually add declarations for both the copy
constructor and assignment operator as private class members. Those
declarations should be prepended with a comment like this:
/*
* Noncopyable
*/
Thread(Thread const &);
Thread &operator = (Thread const &);
In the future, we should revisit these places and try to replace
the pointers with references. In the presence of at least one
reference member, the compiler would no longer implicitly generate
a copy constructor. So we could remove the manual declaration.
Issue #465
Ensure that the timer does not handle timeouts again within 1000
microseconds after the last handling of timeouts. This makes denial of
service attacks harder. This commit does not limit the rate of timeout
signals handled inside the timer but it causes the timer to do it less
often. If a client continuously installs a very small timeout at the
timer it still causes a signal to be submitted to the timer each time
and some extra CPU time to be spent in the internal handling method. But
only every 1000 microseconds this internal handling causes user timeouts
to trigger.
If we would want to limit also the call of the internal handling method
to ensure that CPU time is spent beside the RPCs only every 1000
microseconds, things would get more complex. For instance, on NOVA
Time_source::schedule_timeout(0) must be called each time a new timeout
gets installed and becomes head of the scheduling queue. We cannot
simply overwrite the already running timeout with the new one.
Ref #2490
This patch fixes an aliasing problem of the 'close' method signature
that prevented the Input::Root_component::close method to be called.
This way, the event-queue state was not reset at session-close time,
which prevented a subsequent session-creation request to succeed. With
the patch, input servers like ps2_drv, usb_drv that rely on the
Input::Root_component support the dynamic re-opening of sessions. This
happens in particular when using a dynamically configured input filter.
When we have two time values of an unsigned integer type and we create
the difference and want to know wether it is positive or negative within
the same value we loose at least one half of the value range for casting
to signed integers. This was the case in the alarm scheduler when
checking wether an alarm already triggered. Even worse, we casted from
'unsigned long' to 'signed int' which caused further loss on at least
x86_64. Thus, big timeouts like ~0UL falsely triggered directly.
Now, we use an extra boolean value to remember in which period of the
time counter we are and to which period of the time counter the deadline
of an alarm belongs. This boolean switches its value each time the time
counter wraps. This way, we can avoid any casting by checking wether the
current time is of the same period as the deadline of the alarm that we
inspect. If so, the alarm is pending if "current time >= alarm
deadline", otherwise it is pending if "current time < alarm deadline".
Ref #2490
Session_requester inherits from Dynamic_rom_session::Content_producer
which specifies the Buffer_capacity_exceeded exception which is thrown
on insufficient buffer space.
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).
