This patch switches away from {Nonnull,}LockRefPtr to the non-locking
smart pointers throughout the kernel.
I've looked at the handful of places where these were being persisted
and I don't see any race situations.
Note that the process file descriptor table (Process::m_fds) was already
guarded via MutexProtected.
Before this change, we had File::mmap() which did all the work of
setting up a VMObject, and then creating a Region in the current
process's address space.
This patch simplifies the interface by removing the region part.
Files now only have to return a suitable VMObject from
vmobject_for_mmap(), and then sys$mmap() itself will take care of
actually mapping it into the address space.
This fixes an issue where we'd try to block on I/O (for inode metadata
lookup) while holding the address space spinlock. It also reduces time
spent holding the address space lock.
This forces anyone who wants to look into and/or manipulate an address
space to lock it. And this replaces the previous, more flimsy, manual
spinlock use.
Note that pointers *into* the address space are not safe to use after
you unlock the space. We've got many issues like this, and we'll have
to track those down as wlel.
Until now, our kernel has reimplemented a number of AK classes to
provide automatic internal locking:
- RefPtr
- NonnullRefPtr
- WeakPtr
- Weakable
This patch renames the Kernel classes so that they can coexist with
the original AK classes:
- RefPtr => LockRefPtr
- NonnullRefPtr => NonnullLockRefPtr
- WeakPtr => LockWeakPtr
- Weakable => LockWeakable
The goal here is to eventually get rid of the Lock* classes in favor of
using external locking.
Since RefCounted automatically calls a method named `will_be_destoyed`
on classes that have one, so there's no need to have a custom
implementation of unref in File.
This will allow File and it's descendants to use RefCounted instead of
having a custom implementation of unref. (Since RefCounted calls
will_be_destroyed automatically)
This commit also removes an erroneous call to `before_removing` in
AHCIPort, this is a duplicate call, as the only reference to the device
is immediately dropped following the call, which in turns calls
`before_removing` via File::unref.
We now use AK::Error and AK::ErrorOr<T> in both kernel and userspace!
This was a slightly tedious refactoring that took a long time, so it's
not unlikely that some bugs crept in.
Nevertheless, it does pass basic functionality testing, and it's just
real nice to finally see the same pattern in all contexts. :^)
Instead of doing so in the constructor, let's do immediately after the
constructor, so we can safely pass a reference of a Device, so the
SysFSDeviceComponent constructor can use that object to identify whether
it's a block device or a character device.
This allows to us to not hold a device in SysFSDeviceComponent with a
RefPtr.
Also, we also call the before_removing method in both SlavePTY::unref
and File::unref, so because Device has that method being overrided, it
can ensure the device is removed always cleanly.
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.
...and also RangeAllocator => VirtualRangeAllocator.
This clarifies that the ranges we're dealing with are *virtual* memory
ranges and not anything else.
It's easy to forget the responsibility of validating and safely copying
kernel parameters in code that is far away from syscalls. ioctl's are
one such example, and bugs there are just as dangerous as at the root
syscall level.
To avoid this case, utilize the AK::Userspace<T> template in the ioctl
kernel interface so that implementors have no choice but to properly
validate and copy ioctl pointer arguments.
Advisory locks don't actually prevent other processes from writing to
the file, but they do prevent other processes looking to acquire and
advisory lock on the file.
This implementation currently only adds non-blocking locks, which are
all I need for now.
When there is more than one file descriptor for a file closing
one of them should not close the underlying file.
Previously this relied on the file's ref_count() but at least
for sockets this didn't work reliably.
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 *
Instead of letting each File subclass do range allocation in their
mmap() override, do it up front in sys$mmap().
This makes us honor alignment requests for file-backed memory mappings
and simplifies the code somwhat.
..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.
When ProcFS could no longer allocate KBuffer objects to serve calls to
read, it would just return 0, indicating EOF. This then triggered
parsing errors because code assumed it read the file.
Because read isn't supposed to return ENOMEM, change ProcFS to populate
the file data upon file open or seek to the beginning. This also means
that calls to open can now return ENOMEM if needed. This allows the
caller to either be able to successfully open the file and read it, or
fail to open it in the first place.
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.
You can now mmap a file as private and writable, and the changes you
make will only be visible to you.
This works because internally a MAP_PRIVATE region is backed by a
unique PrivateInodeVMObject instead of using the globally shared
SharedInodeVMObject like we always did before. :^)
Fixes#1045.
Previously, VFS::open() would only use the passed flags for permission checking
purposes, and Process::sys$open() would set them on the created FileDescription
explicitly. Now, they should be set by VFS::open() on any files being opened,
including files that the kernel opens internally.
This also lets us get rid of the explicit check for whether or not the returned
FileDescription was a preopen fd, and in fact, fixes a bug where a read-only
preopen fd without any other flags would be considered freshly opened (due to
O_RDONLY being indistinguishable from 0) and granted a new set of flags.
As suggested by Joshua, this commit adds the 2-clause BSD license as a
comment block to the top of every source file.
For the first pass, I've just added myself for simplicity. I encourage
everyone to add themselves as copyright holders of any file they've
added or modified in some significant way. If I've added myself in
error somewhere, feel free to replace it with the appropriate copyright
holder instead.
Going forward, all new source files should include a license header.
This has been a FIXME for a long time. We now apply the provided
read/write permissions to the constructed FileDescription when opening
a File object via File::open().
Also tweak the kernel's Makefile to use -nostdinc and -nostdinc++.
This prevents us from picking up random headers from ../Root, which may
include older versions of kernel headers.
Since we still need <initializer_list> for Vector, we specifically include
the necessary GCC path. This is a bit hackish but it works for now.
