Commit Graph

58 Commits

Author SHA1 Message Date
Liav A
5dcf03ad9a Kernel/Devices: Introduce the LoopDevice device
This device is a block device that allows a user to effectively treat an
Inode as a block device.

The static construction method is given an OpenFileDescription reference
but validates that:
- The description has a valid custody (so it's not some arbitrary file).
  Failing this requirement will yield EINVAL.
- The description custody points to an Inode which is a regular file, as
  we only support (seekable) regular files. Failing this requirement
  will yield ENOTSUP.

LoopDevice can be used to mount a regular file on the filesystem like
other supported types of (physical) block devices.
2024-03-13 15:33:47 -06:00
Liav A
23a7ccf607 Kernel+LibCore+LibC: Split the mount syscall into multiple syscalls
This is a preparation before we can create a usable mechanism to use
filesystem-specific mount flags.
To keep some compatibility with userland code, LibC and LibCore mount
functions are kept being usable, but now instead of doing an "atomic"
syscall, they do multiple syscalls to perform the complete procedure of
mounting a filesystem.

The FileBackedFileSystem IntrusiveList in the VFS code is now changed to
be protected by a Mutex, because when we mount a new filesystem, we need
to check if a filesystem is already created for a given source_fd so we
do a scan for that OpenFileDescription in that list. If we fail to find
an already-created filesystem we create a new one and register it in the
list if we successfully mounted it. We use a Mutex because we might need
to initiate disk access during the filesystem creation, which will take
other mutexes in other parts of the kernel, therefore making it not
possible to take a spinlock while doing this.
2023-07-02 01:04:51 +02:00
Liav A
c56e1c5378 Kernel/FileSystem: Simplify the ProcFS significantly
Since the ProcFS doesn't hold many global objects within it, the need
for a fully-structured design of backing components and a registry like
with the SysFS is no longer true.

To acommodate this, let's remove all backing store and components of the
ProcFS, so now it resembles what we had in the early days of ProcFS in
the project - a mostly-static filesystem, with very small amount of
kmalloc allocations needed.
We still use the inode index mechanism to understand the role of each
inode, but this is done in a much "static"ier way than before.
2023-02-24 22:14:18 +01:00
Liav A
ed67a877a3 Kernel+SystemServer+Base: Introduce the RAMFS filesystem
This filesystem is based on the code of the long-lived TmpFS. It differs
from that filesystem in one keypoint - its root inode doesn't have a
sticky bit on it.

Therefore, we mount it on /dev, to ensure only root can modify files on
that directory. In addition to that, /tmp is mounted directly in the
SystemServer main (start) code, so it's no longer specified in the fstab
file. We ensure that /tmp has a sticky bit and has the value 0777 for
root directory permissions, which is certainly a special case when using
RAM-backed (and in general other) filesystems.

Because of these 2 changes, it's no longer needed to maintain the TmpFS
filesystem, hence it's removed (renamed to RAMFS), because the RAMFS
represents the purpose of this filesystem in a much better way - it
relies on being backed by RAM "storage", and therefore it's easy to
conclude it's temporary and volatile, so its content is gone on either
system shutdown or unmounting of the filesystem.
2023-02-04 15:32:45 -07:00
Liav A
722ae35329 Kernel/FileSystem: Simplify the ProcFS inode code
This is done by merging all scattered pieces of derived classes from the
ProcFSInode class into that one class, so we don't use inheritance but
rather simplistic checks to determine the proper code for each ProcFS
inode with its specific characteristics.
2023-01-29 12:59:30 +01:00
kleines Filmröllchen
a6a439243f Kernel: Turn lock ranks into template parameters
This step would ideally not have been necessary (increases amount of
refactoring and templates necessary, which in turn increases build
times), but it gives us a couple of nice properties:
- SpinlockProtected inside Singleton (a very common combination) can now
  obtain any lock rank just via the template parameter. It was not
  previously possible to do this with SingletonInstanceCreator magic.
- SpinlockProtected's lock rank is now mandatory; this is the majority
  of cases and allows us to see where we're still missing proper ranks.
- The type already informs us what lock rank a lock has, which aids code
  readability and (possibly, if gdb cooperates) lock mismatch debugging.
- The rank of a lock can no longer be dynamic, which is not something we
  wanted in the first place (or made use of). Locks randomly changing
  their rank sounds like a disaster waiting to happen.
- In some places, we might be able to statically check that locks are
  taken in the right order (with the right lock rank checking
  implementation) as rank information is fully statically known.

This refactoring even more exposes the fact that Mutex has no lock rank
capabilites, which is not fixed here.
2023-01-02 18:15:27 -05:00
Liav A
e882b2ed05 Kernel: Split the FATFileSystem.{cpp,h} files into smaller components 2022-11-08 02:54:48 -07:00
Liav A
5e6101dd3e Kernel: Split the TmpFS core files into smaller components 2022-11-08 02:54:48 -07:00
Liav A
5e062414c1 Kernel: Add support for jails
Our implementation for Jails resembles much of how FreeBSD jails are
working - it's essentially only a matter of using a RefPtr in the
Process class to a Jail object. Then, when we iterate over all processes
in various cases, we could ensure if either the current process is in
jail and therefore should be restricted what is visible in terms of
PID isolation, and also to be able to expose metadata about Jails in
/sys/kernel/jails node (which does not reveal anything to a process
which is in jail).

A lifetime model for the Jail object is currently plain simple - there's
simpy no way to manually delete a Jail object once it was created. Such
feature should be carefully designed to allow safe destruction of a Jail
without the possibility of releasing a process which is in Jail from the
actual jail. Each process which is attached into a Jail cannot leave it
until the end of a Process (i.e. when finalizing a Process). All jails
are kept being referenced in the JailManagement. When a last attached
process is finalized, the Jail is automatically destroyed.
2022-11-05 18:00:58 -06:00
Timon Kruiper
97f1fa7d8f Kernel: Include missing headers for various files
With these missing header files, we can now build these files for
aarch64.
2022-10-26 20:01:45 +02:00
Liav A
97f8927da6 Kernel: Remove the DevTmpFS class
Although this code worked quite well, it is considered to be a code
duplication with the TmpFS code which is more tested and works quite
well for a variety of cases. The only valid reason to keep this
filesystem was that it enforces that no regular files will be created at
all in the filesystem. Later on, we will re-introduce this feature in a
sane manner. Therefore, this can be safely removed after SystemServer no
longer uses this filesystem type anymore.
2022-10-22 19:18:15 +02:00
Andreas Kling
122d7d9533 Kernel: Add Credentials to hold a set of user and group IDs
This patch adds a new object to hold a Process's user credentials:

- UID, EUID, SUID
- GID, EGID, SGID, extra GIDs

Credentials are immutable and child processes initially inherit the
Credentials object from their parent.

Whenever a process changes one or more of its user/group IDs, a new
Credentials object is constructed.

Any code that wants to inspect and act on a set of credentials can now
do so without worrying about data races.
2022-08-20 18:32:50 +02:00
Linus Groh
8150d71821 Everywhere: Prefix 'TYPEDEF_DISTINCT_ORDERED_ID' with 'AK_' 2022-07-22 23:09:43 +01:00
Liav A
1dbd32488f Kernel/SysFS: Add /sys/devices/storage directory
This change in fact does the following:
1. Use support for symlinks between /sys/dev/block/ storage device
identifier nodes and devices in /sys/devices/storage/{LUN}.
2. Add basic nodes in a /sys/devices/storage/{LUN} directory, to let
userspace to know about the device and its details.
2022-07-15 12:29:23 +02:00
Liav A
23c1c40e86 Kernel/SysFS: Migrate components code from SysFS.cpp to the SysFS folder 2022-06-17 11:01:27 +02:00
Liav A
3d22917548 Kernel/Memory: Introduce the SharedFramebufferVMObject class
This new type of VMObject will be used to coordinate switching safely
from graphical mode to text mode and vice-versa, by supplying a way to
remap all Regions that were created with this object, so mappings can be
changed according to the given state of system mode. This makes it quite
easy to give applications like WindowServer the feeling of having full
access to the framebuffer device from a DisplayConnector, but still keep
the Kernel in control to be able to safely switch to text console.
2022-06-06 20:11:05 +01:00
Andreas Kling
e8f543c390 Kernel: Use intrusive RegionTree solution for kernel regions as well
This patch ports MemoryManager to RegionTree as well. The biggest
difference between this and the userspace code is that kernel regions
are owned by extant OwnPtr<Region> objects spread around the kernel,
while userspace regions are owned by the AddressSpace itself.

For kernelspace, there are a couple of situations where we need to make
large VM reservations that never get backed by regular VMObjects
(for example the kernel image reservation, or the big kmalloc range.)
Since we can't make a VM reservation without a Region object anymore,
this patch adds a way to create unbacked Region objects that can be
used for this exact purpose. They have no internal VMObject.)
2022-04-03 21:51:58 +02:00
Andreas Kling
79fa9765ca Kernel: Replace KResult and KResultOr<T> with Error and ErrorOr<T>
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. :^)
2021-11-08 01:10:53 +01:00
Liav A
3d5ddbab74 Kernel: Rename DevFS => DevTmpFS
The current implementation of DevFS resembles the linux devtmpfs, and
not the traditional DevFS, so let's rename it to better represent the
direction of the development in regard to this filesystem.

The abbreviation for DevTmpFS is still "dev", because it doesn't add
value as a commandline option to make it longer.

In quick summary - DevFS in unix OSes is simply a static filesystem, so
device nodes are generated and removed by the kernel code. DevTmpFS
is a "modern reinvention" of the DevFS, so it is much more like a TmpFS
in the sense that not only it's stored entirely in RAM, but the userland
is responsible to add and remove devices nodes as it sees fit, and no
kernel code is directly being involved to keep the filesystem in sync.
2021-09-08 00:42:20 +02:00
Andreas Kling
4a9c18afb9 Kernel: Rename FileDescription => OpenFileDescription
Dr. POSIX really calls these "open file description", not just
"file description", so let's call them exactly that. :^)
2021-09-07 13:53:14 +02:00
Brian Gianforcaro
bb58a4d943 Kernel: Make all Spinlocks use u8 for storage, remove template
The default template argument is only used in one place, and it
looks like it was probably just an oversight. The rest of the Kernel
code all uses u8 as the type. So lets make that the default and remove
the unused template argument, as there doesn't seem to be a reason to
allow the size to be customizable.
2021-09-05 20:46:02 +02:00
Andreas Kling
ae197deb6b Kernel: Strongly typed user & group ID's
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.
2021-08-29 01:09:19 +02:00
Andreas Kling
bcd2025311 Everywhere: Core dump => Coredump
We all know what a coredump is, and it feels more natural to refer to
it as a coredump (most code already does), so let's be consistent.
2021-08-23 00:02:09 +02:00
Andreas Kling
c922a7da09 Kernel: Rename ScopedSpinlock => SpinlockLocker
This matches MutexLocker, and doesn't sound like it's a lock itself.
2021-08-22 03:34:10 +02:00
Andreas Kling
55adace359 Kernel: Rename SpinLock => Spinlock 2021-08-22 03:34:10 +02:00
Andreas Kling
97c497f9fe Kernel: Move {Process,Thread,Session,ProcessGroup}ID to Kernel/Forward.h 2021-08-14 19:58:11 +02:00
Andreas Kling
a1c82041a6 Kernel: Simplify the per-CPU SchedulerData struct 2021-08-08 14:24:54 +02:00
Andreas Kling
b7476d7a1b Kernel: Rename Memory::Space => Memory::AddressSpace 2021-08-06 14:05:58 +02:00
Andreas Kling
cd5faf4e42 Kernel: Rename Range => VirtualRange
...and also RangeAllocator => VirtualRangeAllocator.

This clarifies that the ranges we're dealing with are *virtual* memory
ranges and not anything else.
2021-08-06 14:05:58 +02:00
Andreas Kling
93d98d4976 Kernel: Move Kernel/Memory/ code into Kernel::Memory namespace 2021-08-06 14:05:58 +02:00
Andreas Kling
ec49213f7b Kernel: Add MemoryManager to Forward.h 2021-08-05 17:41:58 +02:00
Andreas Kling
1e43292c3b Kernel: Introduce ProcessorSpecific<T> for per-CPU data structures
To add a new per-CPU data structure, add an ID for it to the
ProcessorSpecificDataID enum.

Then call ProcessorSpecific<T>::initialize() when you are ready to
construct the per-CPU data structure on the current CPU. It can then
be accessed via ProcessorSpecific<T>::get().

This patch replaces the existing hard-coded mechanisms for Scheduler
and MemoryManager per-CPU data structure.
2021-07-27 14:32:30 +02:00
Andreas Kling
b975a74a1d Kernel/USB: Move USB bus information from /proc to /sys
This patch moves all the USB data from /proc/bus/usb to /sys/bus/usb.
2021-07-18 00:55:16 +02:00
Andreas Kling
cee9528168 Kernel: Rename Lock to Mutex
Let's be explicit about what kind of lock this is meant to be.
2021-07-17 21:10:32 +02:00
Andreas Kling
0afccb560b Kernel: Remove some duplicate forward declarations 2021-07-11 15:15:57 +02:00
Andreas Kling
98080497d2 Kernel: Use Forward.h headers more 2021-07-11 14:14:51 +02:00
Andreas Kling
0d39bd04d3 Kernel: Rename VFS => VirtualFileSystem 2021-07-11 00:25:24 +02:00
Brian Gianforcaro
1682f0b760 Everything: Move to SPDX license identifiers in all files.
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 *
2021-04-22 11:22:27 +02:00
Tom
20cccda731 Kernel: Add simplistic work queues
We can't use deferred functions for anything that may require preemption,
such as copying from/to user or accessing the disk. For those purposes
we should use a work queue, which is essentially a kernel thread that
may be preempted or blocked.
2021-03-21 13:41:09 +01:00
Andreas Kling
f1b5def8fd Kernel: Factor address space management out of the Process class
This patch adds Space, a class representing a process's address space.

- Each Process has a Space.
- The Space owns the PageDirectory and all Regions in the Process.

This allows us to reorganize sys$execve() so that it constructs and
populates a new Space fully before committing to it.

Previously, we would construct the new address space while still
running in the old one, and encountering an error meant we had to do
tedious and error-prone rollback.

Those problems are now gone, replaced by what's hopefully a set of much
smaller problems and missing cleanups. :^)
2021-02-08 18:27:28 +01:00
Tom
1d621ab172 Kernel: Some futex improvements
This adds support for FUTEX_WAKE_OP, FUTEX_WAIT_BITSET, FUTEX_WAKE_BITSET,
FUTEX_REQUEUE, and FUTEX_CMP_REQUEUE, as well well as global and private
futex and absolute/relative timeouts against the appropriate clock. This
also changes the implementation so that kernel resources are only used when
a thread is blocked on a futex.

Global futexes are implemented as offsets in VMObjects, so that different
processes can share a futex against the same VMObject despite potentially
being mapped at different virtual addresses.
2021-01-17 20:30:31 +01:00
Andreas Kling
bf0719092f Kernel+Userland: Remove shared buffers (shbufs)
All users of this mechanism have been switched to anonymous files and
passing file descriptors with sendfd()/recvfd().

Shbufs got us where we are today, but it's time we say good-bye to them
and welcome a much more idiomatic replacement. :^)
2021-01-17 09:07:32 +01:00
Itamar
b4842d33bb Kernel: Generate a coredump file when a process crashes
When a process crashes, we generate a coredump file and write it in
/tmp/coredumps/.

The coredump file is an ELF file of type ET_CORE.
It contains a segment for every userspace memory region of the process,
and an additional PT_NOTE segment that contains the registers state for
each thread, and a additional data about memory regions
(e.g their name).
2020-12-14 23:05:53 +01:00
Tom
78f1b5e359 Kernel: Fix some problems with Thread::wait_on and Lock
This changes the Thread::wait_on function to not enable interrupts
upon leaving, which caused some problems with page fault handlers
and in other situations. It may now be called from critical
sections, with interrupts enabled or disabled, and returns to the
same state.

This also requires some fixes to Lock. To aid debugging, a new
define LOCK_DEBUG is added that enables checking for Lock leaks
upon finalization of a Thread.
2020-12-01 09:48:34 +01:00
Tom
046d6855f5 Kernel: Move block condition evaluation out of the Scheduler
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.
2020-11-30 13:17:02 +01:00
Tom
c8d9f1b9c9 Kernel: Make copy_to/from_user safe and remove unnecessary checks
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.
2020-09-13 21:19:15 +02:00
Ben Wiederhake
e8dc99dcad Kernel: Remove spurious ProcessInspectionHandle
The class was removed in 538b985487.
2020-09-12 13:46:15 +02:00
Tom
728de56481 Kernel: Prevent recursive calls into the scheduler
Upon leaving a critical section (such as a SpinLock) we need to
check if we're already asynchronously invoking the Scheduler.
Otherwise we might end up triggering another context switch
as soon as leaving the scheduler lock.

Fixes #2883
2020-08-02 17:15:11 +02:00
Andreas Kling
a19304c9d6 Kernel: Remove a bunch of duplicate forward declarations 2020-08-02 11:01:00 +02:00
Andreas Kling
f2a152e930 Kernel: Simplify the ScopedSpinLock template
We can just templatize the LockType here. This makes my Qt Creator
syntax highlighting work again. :^)
2020-07-30 23:43:37 +02:00