This will make operating with the process-related SVC commands much
nicer in the future (the parameter representing the stack size in
svcStartProcess is a 64-bit value).
These functions act in tandem similar to how a lock or mutex require a
balanced lock()/unlock() sequence.
EnterFatalSection simply increments a counter for how many times it has
been called, while LeaveFatalSection ensures that a previous call to
EnterFatalSection has occured. If a previous call has occurred (the
counter is not zero), then the counter gets decremented as one would
expect. If a previous call has not occurred (the counter is zero), then
an error code is returned.
In some cases, our callbacks were using s64 as a parameter, and in other
cases, they were using an int, which is inconsistent.
To make all callbacks consistent, we can just use an s64 as the type for
late cycles, given it gets rid of the need to cast internally.
While we're at it, also resolve some signed/unsigned conversions that
were occurring related to the callback registration.
One behavior that we weren't handling properly in our heap allocation
process was the ability for the heap to be shrunk down in size if a
larger size was previously requested.
This adds the basic behavior to do so and also gets rid of HeapFree, as
it's no longer necessary now that we have allocations and deallocations
going through the same API function.
While we're at it, fully document the behavior that this function
performs.
Makes it more obvious that this function is intending to stand in for
the actual supervisor call itself, and not acting as a general heap
allocation function.
Also the following change will merge the freeing behavior of HeapFree
into this function, so leaving it as HeapAllocate would be misleading.
In cases where HeapAllocate is called with the same size of the current
heap, we can simply do nothing and return successfully.
This avoids doing work where we otherwise don't have to. This is also
what the kernel itself does in this scenario.
Another holdover from citra that can be tossed out is the notion of the
heap needing to be allocated in different addresses. On the switch, the
base address of the heap will always be managed by the memory allocator
in the kernel, so this doesn't need to be specified in the function's
interface itself.
The heap on the switch is always allocated with read/write permissions,
so we don't need to add specifying the memory permissions as part of the
heap allocation itself either.
This also corrects the error code returned from within the function.
If the size of the heap is larger than the entire heap region, then the
kernel will report an out of memory condition.
The use of a shared_ptr is an implementation detail of the VMManager
itself when mapping memory. Because of that, we shouldn't require all
users of the CodeSet to have to allocate the shared_ptr ahead of time.
It's intended that CodeSet simply pass in the required direct data, and
that the memory manager takes care of it from that point on.
This means we just do the shared pointer allocation in a single place,
when loading modules, as opposed to in each loader.
Makes it more evident that one is for actual code and one is for actual
data. Mutable and static are less than ideal terms here, because
read-only data is technically not mutable, but we were mapping it with
that label.
Given this is utilized by the loaders, this allows avoiding inclusion of
the kernel process definitions where avoidable.
This also keeps the loading format for all executable data separate from
the kernel objects.
This function passes in the desired main applet and library applet
volume levels. We can then just pass those values back within the
relevant volume getter functions, allowing us to unstub those as well.
The initial values for the library and main applet volumes differ. The
main applet volume is 0.25 by default, while the library applet volume
is initialized to 1.0 by default in the services themselves.
Rather than make a global accessor for this sort of thing. We can make
it a part of the thread interface itself. This allows getting rid of a
hidden global accessor in the kernel code.
This condition was checking against the nominal thread priority, whereas
the kernel itself checks against the current priority instead. We were
also assigning the nominal priority, when we should be assigning
current_priority, which takes priority inheritance into account.
This can lead to the incorrect priority being assigned to a thread.
Given we recursively update the relevant threads, we don't need to go
through the whole mutex waiter list. This matches what the kernel does
as well (only accessing the first entry within the waiting list).
Makes it an instantiable class like it is in the actual kernel. This
will also allow removing reliance on global accessors in a following
change, now that we can encapsulate a reference to the system instance
in the class.
Within the kernel, shared memory and transfer memory facilities exist as
completely different kernel objects. They also have different validity
checking as well. Therefore, we shouldn't be treating the two as the
same kind of memory.
They also differ in terms of their behavioral aspect as well. Shared
memory is intended for sharing memory between processes, while transfer
memory is intended to be for transferring memory to other processes.
This breaks out the handling for transfer memory into its own class and
treats it as its own kernel object. This is also important when we
consider resource limits as well. Particularly because transfer memory
is limited by the resource limit value set for it.
While we currently don't handle resource limit testing against objects
yet (but we do allow setting them), this will make implementing that
behavior much easier in the future, as we don't need to distinguish
between shared memory and transfer memory allocations in the same place.
With this, all kernel objects finally have all of their data members
behind an interface, making it nicer to reason about interactions with
other code (as external code no longer has the freedom to totally alter
internals and potentially messing up invariants).
After doing a little more reading up on the Opus codec, it turns out
that the multistream API that is part of libopus can handle regular
packets. Regular packets are just a degenerate case of multistream Opus
packets, and all that's necessary is to pass the number of streams as 1
and provide a basic channel mapping, then everything works fine for
that case.
This allows us to get rid of the need to use both APIs in the future
when implementing multistream variants in a follow-up PR, greatly
simplifying the code that needs to be written.
Previously this was required, as BitField wasn't trivially copyable.
BitField has since been made trivially copyable, so now this isn't
required anymore.
Relocates the error code to where it's most related, similar to how all
the other error codes are. Previously we were including a non-generic
error in the main result code header.
These can just be passed regularly, now that we use fmt instead of our
old logging system.
While we're at it, make the parameters to MakeFunctionString
std::string_views.
There's no real need to use a shared lifetime here, since we don't
actually expose them to anything else. This is also kind of an
unnecessary use of the heap given the objects themselves are so small;
small enough, in fact that changing over to optionals actually reduces
the overall size of the HLERequestContext struct (818 bytes to 808
bytes).
Now that we have the address arbiter extracted to its own class, we can
fix an innaccuracy with the kernel. Said inaccuracy being that there
isn't only one address arbiter. Each process instance contains its own
AddressArbiter instance in the actual kernel.
This fixes that and gets rid of another long-standing issue that could
arise when attempting to create more than one process.
Similar to how WaitForAddress was isolated to its own function, we can
also move the necessary conditional checking into the address arbiter
class itself, allowing us to hide the implementation details of it from
public use.
Rather than let the service call itself work out which function is the
proper one to call, we can make that a behavior of the arbiter itself,
so we don't need to directly expose those implementation details.
This will be utilized by more than just that class in the future. This
also renames it from OpusHeader to OpusPacketHeader to be more specific
about what kind of header it is.
Places all error codes in an easily includable header.
This also corrects the unsupported error code (I accidentally used the
hex value when I meant to use the decimal one).
Places all of the functions for address arbiter operation into a class.
This will be necessary for future deglobalizing efforts related to both
the memory and system itself.
Removes a few inclusion dependencies from the headers or replaces
existing ones with ones that don't indirectly include the required
headers.
This allows removing an inclusion of core/memory.h, meaning that if the
memory header is ever changed in the future, it won't result in
rebuilding the entirety of the HLE services (as the IPC headers are used
quite ubiquitously throughout the HLE service implementations).
Avoids directly relying on the global system instance and instead makes
an arbitrary system instance an explicit dependency on construction.
This also allows removing dependencies on some global accessor functions
as well.
Given we already pass in a reference to the kernel that the shared
memory instance is created under, we can just use that to check the
current process, rather than using the global accessor functions.
This allows removing direct dependency on the system instance entirely.
This currently has the same behavior as the regular
OpenAudioRenderer API function, so we can just move the code within
OpenAudioRenderer to an internal function that both service functions
call.
This service function appears to do nothing noteworthy on the switch.
All it does at the moment is either return an error code or abort the
system. Given we obviously don't want to kill the system, we just opt
for always returning the error code.
Provides names for previously unknown entries (aside from the two u8
that appear to be padding bytes, and a single word that also appears
to be reserved or padding).
This will be useful in subsequent changes when unstubbing behavior related
to the audio renderer services.
This function is also supposed to check its given policy type with the
permission of the service itself. This implements the necessary
machinery to unstub these functions.
Policy::User seems to just be basic access (which is probably why vi:u
is restricted to that policy), while the other policy seems to be for
extended abilities regarding which displays can be managed and queried,
so this is assumed to be for a background compositor (which I've named,
appropriately, Policy::Compositor).
There's no real reason this shouldn't be allowed, given some values sent
via a request can be signed. This also makes it less annoying to work
with popping enum values, given an enum class with no type specifier
will work out of the box now.
It's also kind of an oversight to allow popping s64 values, but nothing
else.
This didn't really provide much benefit here, especially since the
subsequent change requires that the behavior for each service's
GetDisplayService differs in a minor detail.
This also arguably makes the services nicer to read, since it gets rid
of an indirection in the class hierarchy.
The kernel allows restricting the total size of the handle table through
the process capability descriptors. Until now, this functionality wasn't
hooked up. With this, the process handle tables become properly restricted.
In the case of metadata-less executables, the handle table will assume
the maximum size is requested, preserving the behavior that existed
before these changes.
The NVFlinger service is already passed into services that need to
guarantee its lifetime, so the BufferQueue instances will already live
as long as they're needed. Making them std::shared_ptr instances in this
case is unnecessary.
Like the previous changes made to the Display struct, this prepares the
Layer struct for changes to its interface. Given Layer will be given
more invariants in the future, we convert it into a class to better
signify that.
With the display and layer structures relocated to the vi service, we
can begin giving these a proper interface before beginning to properly
support the display types.
This converts the display struct into a class and provides it with the
necessary functions to preserve behavior within the NVFlinger class.
These are more closely related to the vi service as opposed to the
intermediary nvflinger.
This also places them in their relevant subfolder, as future changes to
these will likely result in subclassing to represent various displays
and services, as they're done within the service itself on hardware.
The reasoning for prefixing the display and layer source files is to
avoid potential clashing if two files with the same name are compiled
(e.g. if 'display.cpp/.h' or 'layer.cpp/.h' is added to another service
at any point), which MSVC will actually warn against. This prevents that
case from occurring.
This also presently coverts the std::array introduced within
f45c25aaba back to a std::vector to allow
the forward declaration of the Display type. Forward declaring a type
within a std::vector is allowed since the introduction of N4510
(http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4510.html) by
Zhihao Yuan.
A fairly trivial change. Other sections of the codebase use nested
namespaces instead of separate namespaces here. This one must have just
been overlooked.
Gets rid of the largest set of mutable global state within the core.
This also paves a way for eliminating usages of GetInstance() on the
System class as a follow-up.
Note that no behavioral changes have been made, and this simply extracts
the functionality into a class. This also has the benefit of making
dependencies on the core timing functionality explicit within the
relevant interfaces.
Places all of the timing-related functionality under the existing Core
namespace to keep things consistent, rather than having the timing
utilities sitting in its own completely separate namespace.
This commit it automatically generated by command in zsh:
sed -i -- 's/BitField<\(.*\)_le>/BitField<\1>/g' **/*(D.)
BitField is now aware to endianness and default to little endian. It expects a value representation type without storage specification for its template parameter.
Converts many of the Find* functions to return a std::optional<T> as
opposed to returning the raw return values directly. This allows
removing a few assertions and handles error cases like the service
itself does.
A holdover from citra, the Horizon kernel on the switch has no
prominent kernel object that functions as a timer. At least not
to the degree of sophistication that this class provided.
As such, this can be removed entirely. This class also wasn't used at
all in any meaningful way within the core, so this was just code sitting
around doing nothing. This also allows removing a few things from the
main KernelCore class that allows it to use slightly less resources
overall (though very minor and not anything really noticeable).
No inheritors of the WaitObject class actually make use of their own
implementations of these functions, so they can be made non-virtual.
It's also kind of sketchy to allow overriding how the threads get added
to the list anyways, given the kernel itself on the actual hardware
doesn't seem to customize based off this.
This functions almost identically to DecodeInterleavedWithPerfOld,
however this function also has the ability to reset the decoder context.
This is documented as a potentially desirable thing in the libopus
manual in some circumstances as it says for the OPUS_RESET_STATE ctl:
"This should be called when switching streams in order to prevent the
back to back decoding from giving different result from one at a time
decoding."
In addition to the default, external, EDID, and internal displays,
there's also a null display provided as well, which as the name
suggests, does nothing but discard all commands given to it. This is
provided for completeness.
Opening a display isn't really a thing to warn about. It's an expected
thing, so this can be a debug log. This also alters the string to
indicate the display name better.
Opening "Default" display reads a little nicer compared to Opening
display Default.
This quite literally functions as a basic setter. No other error
checking or anything (since there's nothing to really check against).
With this, it completes the pm:bm interface in terms of functionality.
This appears to be a vestigial API function that's only kept around for
compatibility's sake, given the function only returns a success error
code and exits.
Since that's the case, we can remove the stubbed notification from the
log, since doing nothing is technically the correct behavior in this
case.
Looking into the implementation of the C++ standard facilities that seem
to be within all modules, it appears that they use 7 as a break reason
to indicate an uncaught C++ exception.
This was primarily found via the third last function called within
Horizon's equivalent of libcxxabi's demangling_terminate_handler(),
which passes the value 0x80000007 to svcBreak.
This is a function that definitely doesn't always have a non-modifying
behavior across all implementations, so this should be made non-const.
This gets rid of the need to mark data members as mutable to work around
the fact mutating data members needs to occur.
These values are not equivalent, based off RE. The internal value is put
into a lookup table with the following values:
[3, 0, 1, 2, 4]
So the values absolutely do not map 1:1 like the comment was indicating.
Avoids entangling the IPC buffer appending with the actual operation of
converting the scaling values over. This also inserts the proper error
handling for invalid scaling values.
This appears to only check if the scaling mode can actually be
handled, rather than actually setting the scaling mode for the layer.
This implements the same error handling performed on the passed in
values.
Within the actual service, it makes no distinguishing between docked and
undocked modes. This will always return the constants values reporting
1280x720 as the dimensions.
This IPC command is simply a stub inside the actual service itself, and
just returns a successful error code regardless of input. This is likely
only retained in the service interface to not break older code that relied
upon it succeeding in some way.
In many cases, we didn't bother to log out any of the popped data
members. This logs them out to the console within the logging call to
provide more contextual information.
Internally within the vi services, this is essentially all that
OpenDefaultDisplay does, so it's trivial to just do the same, and
forward the default display string into the function.
It appears that the two members indicate whether a display has a bounded
number of layers (and if set, the second member indicates the total
number of layers).
This is a bounds check to ensure that the thread priority is within the
valid range of 0-64. If it exceeds 64, that doesn't necessarily mean
that an actual priority of 64 was expected (it actually means whoever
called the function screwed up their math).
Instead clarify the message to indicate the allowed range of thread
priorities.
Now that we handle the kernel capability descriptors we can correct
CreateThread to properly check against the core and priority masks
like the actual kernel does.
This makes the naming more closely match its meaning. It's just a
preferred core, not a required default core. This also makes the usages
of this term consistent across the thread and process implementations.
This function isn't a general purpose function that should be exposed to
everything, given it's specific to initializing the main thread for a
Process instance.
Given that, it's a tad bit more sensible to place this within
process.cpp, which keeps it visible only to the code that actually needs
it.
In all cases that these functions are needed, the VMManager can just be
retrieved and used instead of providing the same functions in Process'
interface.
This also makes it a little nicer dependency-wise, since it gets rid of
cases where the VMManager interface was being used, and then switched
over to using the interface for a Process instance. Instead, it makes
all accesses uniform and uses the VMManager instance for all necessary
tasks.
All the basic memory mapping functions did was forward to the Process'
VMManager instance anyways.
Similar to the service capability flags, however, we currently don't
emulate the GIC, so this currently handles all interrupts as being valid
for the time being.
Handles the priority mask and core mask flags to allow building up the
masks to determine the usable thread priorities and cores for a kernel
process instance.
We've had the old kernel capability parser from Citra, however, this is
unused code and doesn't actually map to how the kernel on the Switch
does it. This introduces the basic functional skeleton for parsing
process capabilities.
If a thread handle is passed to svcGetProcessId, the kernel attempts to
access the process ID via the thread's instance's owning process.
Technically, this function should also be handling the kernel debug
objects as well, however we currently don't handle those kernel objects
yet, so I've left a note via a comment about it to remind myself when
implementing it in the future.
Starts the process ID counter off at 81, which is what the kernel itself
checks against internally when creating processes. It's actually
supposed to panic if the PID is less than 81 for a userland process.
Now it also indicates the name and max session count. This also gives a
name to the unknown bool. This indicates if the created port is supposed
to be using light handles or regular handles internally. This is passed
to the respective svcCreatePort parameter internally.
Adds the barebones enumeration constants and functions in place to
handle memory attributes, while also essentially leaving the attribute
itself non-functional.
Services created with the ServiceFramework base class install themselves as HleHandlers with an owning shared_ptr in the ServerPort ServiceFrameworkBase::port member variable, creating a cyclic ownership between ServiceFrameworkBase and the ServerPort, preventing deletion of the service objects.
Fix that by removing the ServiceFrameworkBase::port member because that was only used to detect multiple attempts at installing a port. Instead store a flag if the port was already installed to achieve the same functionality.
In the previous change, the memory writing was moved into the service
function itself, however it still had a problem, in that the entire
MemoryInfo structure wasn't being written out, only the first 32 bytes
of it were being written out. We still need to write out the trailing
two reference count members and zero out the padding bits.
Not doing this can result in wrong behavior in userland code in the following
scenario:
MemoryInfo info; // Put on the stack, not quaranteed to be zeroed out.
svcQueryMemory(&info, ...);
if (info.device_refcount == ...) // Whoops, uninitialized read.
This can also cause the wrong thing to happen if the user code uses
std::memcmp to compare the struct, with another one (questionable, but
allowed), as the padding bits are not guaranteed to be a deterministic
value. Note that the kernel itself also fully zeroes out the structure
before writing it out including the padding bits.
Moves the memory writes directly into QueryProcessMemory instead of
letting the wrapper function do it. It would be inaccurate to allow the
handler to do it because there's cases where memory shouldn't even be
written to. For example, if the given process handle is invalid.
HOWEVER, if the memory writing is within the wrapper, then we have no
control over if these memory writes occur, meaning in an error case, 68
bytes of memory randomly get trashed with zeroes, 64 of those being
written to wherever the memory info address points to, and the remaining
4 being written wherever the page info address points to.
One solution in this case would be to just conditionally check within
the handler itself, but this is kind of smelly, given the handler
shouldn't be performing conditional behavior itself, it's a behavior of
the managed function. In other words, if you remove the handler from the
equation entirely, does the function still retain its proper behavior?
In this case, no.
Now, we don't potentially trash memory from this function if an invalid
query is performed.
This would result in svcSetMemoryAttribute getting the wrong value for
its third parameter. This is currently fine, given the service function
is stubbed, however this will be unstubbed in a future change, so this
needs to change.
The kernel returns a memory info instance with the base address set to
the end of the address space, and the size of said block as
0 - address_space_end, it doesn't set both of said members to zero.
Gets the two structures out of an unrelated header and places them with
the rest of the memory management code.
This also corrects the structures. PageInfo appears to only contain a
32-bit flags member, and the extra padding word in MemoryInfo isn't
necessary.
Amends the MemoryState enum to use the same values like the actual
kernel does. Also provides the necessary operators to operate on them.
This will be necessary in the future for implementing
svcSetMemoryAttribute, as memory block state is checked before applying
the attribute.
The Process object kept itself alive indefinitely because its handle_table
contains a SharedMemory object which owns a reference to the same Process object,
creating a circular ownership scenario.
Break that up by storing only a non-owning pointer in the SharedMemory object.
Based off RE, the backing code only ever seems to use 0-2 as the range
of values 1 being a generic log enable, with 2 indicating logging should
go to the SD card. These are used as a set of flags internally.
Given we only care about receiving the log in general, we can just
always signify that we want logging in general.
This was causing some games (most notably Pokemon Quest) to softlock due to an event being fired when not supposed to. This also removes a hack wherein we were firing the state changed event when the game retrieves it, which is incorrect.
This was only ever public so that code could check whether or not a
handle was valid or not. Instead of exposing the object directly and
allowing external code to potentially mess with the map contents, we
just provide a member function that allows checking whether or not a
handle is valid.
This makes all member variables of the VMManager class private except
for the page table.
These auto-deduce the result based off its arguments, so there's no need
to do that work for the compiler, plus, the function return value itself
already indicates what we're returning.
While partially correct, this service call allows the retrieved event to
be null, as it also uses the same handle to check if it was referring to
a Process instance. The previous two changes put the necessary machinery
in place to allow for this, so we can simply call those member functions
here and be done with it.
Process instances can be waited upon for state changes. This is also
utilized by svcResetSignal, which will be modified in an upcoming
change. This simply puts all of the WaitObject related machinery in
place.
svcResetSignal relies on the event instance to have already been
signaled before attempting to reset it. If this isn't the case, then an
error code has to be returned.
This function simply does a handle table lookup for a writable event
instance identified by the given handle value. If a writable event
cannot be found for the given handle, then an invalid handle error is
returned. If a writable event is found, then it simply signals the
event, as one would expect.
svcCreateEvent operates by creating both a readable and writable event
and then attempts to add both to the current process' handle table.
If adding either of the events to the handle table fails, then the
relevant error from the handle table is returned.
If adding the readable event after the writable event to the table
fails, then the writable event is removed from the handle table and the
relevant error from the handle table is returned.
Note that since we do not currently test resource limits, we don't check
the resource limit table yet.
Two kernel object should absolutely never have the same handle ID type.
This can cause incorrect behavior when it comes to retrieving object
types from the handle table. In this case it allows converting a
WritableEvent into a ReadableEvent and vice-versa, which is undefined
behavior, since the object types are not the same.
This also corrects ClearEvent() to check both kernel types like the
kernel itself does.
Previously, ILibraryAppletAccessor would signal upon creation of any applet, but this is incorrect. A flag inside of the applet code determines whether or not creation should signal state change and swkbd happens to be one of these applets.
The kernel uses the handle table of the current process to retrieve the
process that should be used to retrieve certain information. To someone
not familiar with the kernel, this might raise the question of "Ok,
sounds nice, but doesn't this make it impossible to retrieve information
about the current process?".
No, it doesn't, because HandleTable instances in the kernel have the
notion of a "pseudo-handle", where certain values allow the kernel to
lookup objects outside of a given handle table. Currently, there's only
a pseudo-handle for the current process (0xFFFF8001) and a pseudo-handle
for the current thread (0xFFFF8000), so to retrieve the current process,
one would just pass 0xFFFF8001 into svcGetInfo.
The lookup itself in the handle table would be something like:
template <typename T>
T* Lookup(Handle handle) {
if (handle == PSEUDO_HANDLE_CURRENT_PROCESS) {
return CurrentProcess();
}
if (handle == PSUEDO_HANDLE_CURRENT_THREAD) {
return CurrentThread();
}
return static_cast<T*>(&objects[handle]);
}
which, as is shown, allows accessing the current process or current
thread, even if those two objects aren't actually within the HandleTable
instance.
Our implementation of svcGetInfo was slightly incorrect in that we
weren't doing proper error checking everywhere. Instead, reorganize it
to be similar to how the kernel seems to do it.
We can just return a new instance of this when it's requested. This only
ever holds pointers to the existing registed caches, so it's not a large
object. Plus, this also gets rid of the need to keep around a separate
member function just to properly clear out the union.
Gets rid of one of five globals in the filesystem code.
This is the same behavior-wise as DeleteDirectoryRecursively, with the
only difference being that it doesn't delete the top level directory in
the hierarchy, so given:
root_dir/
- some_dir/
- File.txt
- OtherFile.txt
The end result is just:
root_dir/
More hardware accurate. On the actual system, there is a differentiation between the signaler and signalee, they form a client/server relationship much like ServerPort and ClientPort.
The opposite of the getter functions, this function sets the limit value
for a particular ResourceLimit resource category, with the restriction
that the new limit value must be equal to or greater than the current
resource value. If this is violated, then ERR_INVALID_STATE is returned.
e.g.
Assume:
current[Events] = 10;
limit[Events] = 20;
a call to this service function lowering the limit value to 10 would be
fine, however, attempting to lower it to 9 in this case would cause an
invalid state error.
This kernel service function is essentially the exact same as
svcGetResourceLimitLimitValue(), with the only difference being that it
retrieves the current value for a given resource category using the
provided resource limit handle, rather than retrieving the limiting
value of that resource limit instance.
Given these are exactly the same and only differ on returned values, we
can extract the existing code for svcGetResourceLimitLimitValue() to
handle both values.
This kernel service function retrieves the maximum allowable value for
a provided resource category for a given resource limit instance. Given
we already have the functionality added to the resource limit instance
itself, it's sufficient to just hook it up.
The error scenarios for this are:
1. If an invalid resource category type is provided, then ERR_INVALID_ENUM is returned.
2. If an invalid handle is provided, then ERR_INVALID_HANDLE is returned (bad thing goes in, bad thing goes out, as one would expect).
If neither of the above error cases occur, then the out parameter is
provided with the maximum limit value for the given category and success
is returned.
This function simply creates a ResourceLimit instance and attempts to
create a handle for it within the current process' handle table. If the
kernal fails to either create the ResourceLimit instance or create a
handle for the ResourceLimit instance, it returns a failure code
(OUT_OF_RESOURCE, and HANDLE_TABLE_FULL respectively). Finally, it exits
by providing the output parameter with the handle value for the
ResourceLimit instance and returning that it was successful.
Note: We do not return OUT_OF_RESOURCE because, if yuzu runs out of
available memory, then new will currently throw. We *could* allocate the
kernel instance with std::nothrow, however this would be inconsistent
with how all other kernel objects are currently allocated.
Avoids the need to create a copy of the std::string instance
(potentially allocating).
The only reason RegisterService takes its argument by value is because
it's std::moved internally.
