This commit moves the KResult and KResultOr objects to Kernel/API to
signify that they may now be freely used by userspace code at points
where a syscall-related error result is to be expected. It also exposes
KResult and KResultOr to the global namespace to make it nicer to use
for userspace code.
Like with the ProcFS, description data can change at anytime, so it's
wise to ensure that when the userland reads from an Inode, data is
consistent unless the userland indicated it wants to refresh the data
(by seeking to offset 0, or re-attaching the Inode).
Otherwise, if the data changes in the middle of the reading, it can
cause silent corruption in output which can lead to random crashes.
Our existing implementation did not check the element type of the other
pointer in the constructors and move assignment operators. This meant
that some operations that would require explicit casting on raw pointers
were done implicitly, such as:
- downcasting a base class to a derived class (e.g. `Kernel::Inode` =>
`Kernel::ProcFSDirectoryInode` in Kernel/ProcFS.cpp),
- casting to an unrelated type (e.g. `Promise<bool>` => `Promise<Empty>`
in LibIMAP/Client.cpp)
This, of course, allows gross violations of the type system, and makes
the need to type-check less obvious before downcasting. Luckily, while
adding the `static_ptr_cast`s, only two truly incorrect usages were
found; in the other instances, our casts just needed to be made
explicit.
Prior to this change, both uid_t and gid_t were typedef'ed to `u32`.
This made it easy to use them interchangeably. Let's not allow that.
This patch adds UserID and GroupID using the AK::DistinctNumeric
mechanism we've already been employing for pid_t/ProcessID.
Instead of registering with blocker sets and whatnot in the various
Blocker subclass constructors, this patch moves such initialization
to a separate setup_blocker() virtual.
setup_blocker() returns false if there's no need to actually block
the thread. This allows us to bail earlier in Thread::block().
Namely, will_unblock_immediately_without_blocking(Reason).
This virtual function is called on a blocker *before any block occurs*,
if it turns out that we don't need to block the thread after all.
This can happens for one of two reasons:
- UnblockImmediatelyReason::UnblockConditionAlreadyMet
We don't need to block the thread because the condition for
unblocking it is already met.
- UnblockImmediatelyReason::TimeoutInThePast
We don't need to block the thread because a timeout was specified
and that timeout is already in the past.
This patch does not introduce any behavior changes, it's only meant to
clarify this part of the blocking logic.
Namely, unblock_all_blockers_whose_conditions_are_met().
The old name made it sound like things were getting unblocked no matter
what, but that's not actually the case.
What this actually does is iterate through the set of blockers,
unblocking those whose conditions are met. So give it a (very) verbose
name that errs on the side of descriptiveness.
This has several benefits:
1) We no longer just blindly derefence a null pointer in various places
2) We will get nicer runtime error messages if the current process does
turn out to be null in the call location
3) GCC no longer complains about possible nullptr dereferences when
compiling without KUBSAN
This is primarily to be able to remove the GenericLexer include out of
Format.h as well. A subsequent commit will add AK::Result to
GenericLexer, which will cause naming conflicts with other structures
named Result. This can be avoided (for now) by preventing nearly every
file in the system from implicitly including GenericLexer.
Other changes in this commit are to add the GenericLexer include to
files where it is missing.
We don't need to access the Custody cache in IRQs or anything like that,
so it should be fine to use a regular Mutex (via ProtectedValue.)
This allows threads to block while waiting for the custody cache.
Thanks to Sergey for pointing this out. :^)
Usage patterns mean we are more likely to need a Custody we just cached.
Because lookup walks the list from the beginning, prepending new items
instead of appending means they will be found quicker.
This reduces the number of items in the cache we need to walk by 50% for
boot and application startups.
Use a StringBuilder to generate a temporary string buffer with the
slave PTY names. (This works because StringBuilder has 128 bytes of
inline stack capacity before it does any heap allocations.)
This simplifies the DevPtsFS implementation somewhat, as it no longer
requires SlavePTY to register itself with it, since it can now simply
use the list of SlavePTY instances.
Make File inherit from RefCountedBase and provide a custom unref()
implementation. This will allow subclasses that participate in lists to
remove themselves in a safe way when being destroyed.
This patch adds a (spinlock-protected) custody cache. It's a simple
intrusive list containing all currently live custody objects.
This allows us to re-use existing custodies instead of creating them
again and again.
This gives a pretty decent performance improvement on "find /" :^)
We are not using this for anything and it's just been sitting there
gathering dust for well over a year, so let's stop carrying all this
complexity around for no good reason.
This allows us to 1) let go of the Process when an inode is ref'ing for
ProcFSExposedComponent related reasons, and 2) change our ref/unref
implementation.
This patch removes KResult::operator int() and deals with the fallout.
This forces a lot of code to be more explicit in its handling of errors,
greatly improving readability.
