The error handling in all these cases was still using the old style
negative values to indicate errors. We have a nicer solution for this
now with KResultOr<T>. This change switches the interface and then all
implementers to use the new style.
SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
(...and ASSERT_NOT_REACHED => VERIFY_NOT_REACHED)
Since all of these checks are done in release builds as well,
let's rename them to VERIFY to prevent confusion, as everyone is
used to assertions being compiled out in release.
We can introduce a new ASSERT macro that is specifically for debug
checks, but I'm doing this wholesale conversion first since we've
accumulated thousands of these already, and it's not immediately
obvious which ones are suitable for ASSERT.
..and allow implicit creation of KResult and KResultOr from ErrnoCode.
This means that kernel functions that return those types can finally
do "return EINVAL;" and it will just work.
There's a handful of functions that still deal with signed integers
that should be converted to return KResults.
Problem:
- Many constructors are defined as `{}` rather than using the ` =
default` compiler-provided constructor.
- Some types provide an implicit conversion operator from `nullptr_t`
instead of requiring the caller to default construct. This violates
the C++ Core Guidelines suggestion to declare single-argument
constructors explicit
(https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#c46-by-default-declare-single-argument-constructors-explicit).
Solution:
- Change default constructors to use the compiler-provided default
constructor.
- Remove implicit conversion operators from `nullptr_t` and change
usage to enforce type consistency without conversion.
These changes are arbitrarily divided into multiple commits to make it
easier to find potentially introduced bugs with git bisect.Everything:
The modifications in this commit were automatically made using the
following command:
find . -name '*.cpp' -exec sed -i -E 's/dbg\(\) << ("[^"{]*");/dbgln\(\1\);/' {} \;
Compared to version 10 this fixes a bunch of formatting issues, mostly
around structs/classes with attributes like [[gnu::packed]], and
incorrect insertion of spaces in parameter types ("T &"/"T &&").
I also removed a bunch of // clang-format off/on and FIXME comments that
are no longer relevant - on the other hand it tried to destroy a couple of
neatly formatted comments, so I had to add some as well.
The unblock_all variant used to ASSERT if a blocker didn't unblock,
but it wasn't clear from the name that it would do that. Because
the BlockCondition already asserts that no blockers are left at
destruction time, it would still catch blockers that haven't been
unblocked for whatever reason.
Fixes#4496
Problem:
- `(void)` simply casts the expression to void. This is understood to
indicate that it is ignored, but this is really a compiler trick to
get the compiler to not generate a warning.
Solution:
- Use the `[[maybe_unused]]` attribute to indicate the value is unused.
Note:
- Functions taking a `(void)` argument list have also been changed to
`()` because this is not needed and shows up in the same grep
command.
This makes the Scheduler a lot leaner by not having to evaluate
block conditions every time it is invoked. Instead evaluate them as
the states change, and unblock threads at that point.
This also implements some more waitid/waitpid/wait features and
behavior. For example, WUNTRACED and WNOWAIT are now supported. And
wait will now not return EINTR when SIGCHLD is delivered at the
same time.
Since the CPU already does almost all necessary validation steps
for us, we don't really need to attempt to do this. Doing it
ourselves doesn't really work very reliably, because we'd have to
account for other processors modifying virtual memory, and we'd
have to account for e.g. pages not being able to be allocated
due to insufficient resources.
So change the copy_to/from_user (and associated helper functions)
to use the new safe_memcpy, which will return whether it succeeded
or not. The only manual validation step needed (which the CPU
can't perform for us) is making sure the pointers provided by user
mode aren't pointing to kernel mappings.
To make it easier to read/write from/to either kernel or user mode
data add the UserOrKernelBuffer helper class, which will internally
either use copy_from/to_user or directly memcpy, or pass the data
through directly using a temporary buffer on the stack.
Last but not least we need to keep syscall params trivial as we
need to copy them from/to user mode using copy_from/to_user.
Unlike DirectoryEntry (which is used when constructing directories),
DirectoryEntryView does not manage storage for file names. Names are
just StringViews.
This is much more suited to the directory traversal API and makes
it easier to implement this in file system classes since they no
longer need to create temporary name copies while traversing.
The SI prefixes "k", "M", "G" mean "10^3", "10^6", "10^9".
The IEC prefixes "Ki", "Mi", "Gi" mean "2^10", "2^20", "2^30".
Let's use the correct name, at least in code.
Only changes the name of the constants, no other behavior change.
Certain implementations of Inode::directory_entry_count were calling
functions which returned errors, but had no way of surfacing them.
Switch the return type to KResultOr<size_t> and start observing these
error paths.
Allow passing in an optional timeout to Thread::block and move
the timeout check out of Thread::Blocker. This way all Blockers
implicitly support timeouts and don't need to implement it
themselves. Do however allow them to override timeouts (e.g.
for sockets).
We need to have a Thread lock to protect threading related
operations, such as Thread::m_blocker which is used in
Thread::block.
Also, if a Thread::Blocker indicates that it should be
unblocking immediately, don't actually block the Thread
and instead return immediately in Thread::block.
We now have BlockResult::WokeNormally and BlockResult::NotBlocked,
both of which indicate no error. We can no longer just check for
BlockResult::WokeNormally and assume anything else must be an
interruption.
