This class is intended to replace all IOAddress usages in the Kernel
codebase altogether. The idea is to ensure IO can be done in
arch-specific manner that is determined mostly in compile-time, but to
still be able to use most of the Kernel code in non-x86 builds. Specific
devices that rely on x86-specific IO instructions are already placed in
the Arch/x86 directory and are omitted for non-x86 builds.
The reason this works so well is the fact that x86 IO space acts in a
similar fashion to the traditional memory space being available in most
CPU architectures - the x86 IO space is essentially just an array of
bytes like the physical memory address space, but requires x86 IO
instructions to load and store data. Therefore, many devices allow host
software to interact with the hardware registers in both ways, with a
noticeable trend even in the modern x86 hardware to move away from the
old x86 IO space to exclusively using memory-mapped IO.
Therefore, the IOWindow class encapsulates both methods for x86 builds.
The idea is to allow PCI devices to be used in either way in x86 builds,
so when trying to map an IOWindow on a PCI BAR, the Kernel will try to
find the proper method being declared with the PCI BAR flags.
For old PCI hardware on non-x86 builds this might turn into a problem as
we can't use port mapped IO, so the Kernel will gracefully fail with
ENOTSUP error code if that's the case, as there's really nothing we can
do within such case.
For general IO, the read{8,16,32} and write{8,16,32} methods are
available as a convenient API for other places in the Kernel. There are
simply no direct 64-bit IO API methods yet, as it's not needed right now
and is not considered to be Arch-agnostic too - the x86 IO space doesn't
support generating 64 bit cycle on IO bus and instead requires two 2
32-bit accesses. If for whatever reason it appears to be necessary to do
IO in such manner, it could probably be added with some neat tricks to
do so. It is recommended to use Memory::TypedMapping struct if direct 64
bit IO is actually needed.
Instead of temporary changing the open file description's "blocking"
flag while doing a non-waiting recvfrom, we instead plumb the currently
wanted blocking behavior all the way through to the underlying socket.
This ensures that all the permissions checks are made against the
provided credentials. Previously we were just calling through directly
to the inode setters, which did no security checks!
Instead of getting credentials from Process::current(), we now require
that they be provided as input to the various VFS functions.
This ensures that an atomic set of credentials is used throughout an
entire VFS operation.
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.
Instead of having two separate implementations of AK::RefCounted, one
for userspace and one for kernelspace, there is now RefCounted and
AtomicRefCounted.
All users which relied on the default constructor use a None lock rank
for now. This will make it easier to in the future remove LockRank and
actually annotate the ranks by searching for None.
We were previously rejecting `SO_REUSEADDR` with an `ENOPROTOOPT`, but
that made QEMU unhappy. Instead, just silently discard it and print a
FIXME message in case anybody wonders what went wrong if the system
won't reuse an address.
This argument is always set to description.is_blocking(), but
description is also given as a separate argument, so there's no point
to piping it through separately.
Each of these strings would previously rely on StringView's char const*
constructor overload, which would call __builtin_strlen on the string.
Since we now have operator ""sv, we can replace these with much simpler
versions. This opens the door to being able to remove
StringView(char const*).
No functional changes.
This commit moves the length calculations out to be directly on the
StringView users. This is an important step towards the goal of removing
StringView(char const*), as it moves the responsibility of calculating
the size of the string to the user of the StringView (which will prevent
naive uses causing OOB access).
This is not explicitly specified by POSIX, but is supported by other
*nixes, already supported by our sys$bind, and expected by various
programs. While were here, also clean up the user memory copies a bit.
We were previously assuming that the how value was a bitfield, but that
is not the case, so we must explicitly check for SHUT_RDWR when
deciding on the read and write shutdowns.
To prevent a race condition in case we received the ARP response in the
window between creating and initializing the Thread Blocker and the
actual blocking, we were checking if the IP address was updated in the
ARP table just before starting to block.
Unfortunately, the condition was partially flipped, which meant that if
the table was updated with the IP address we would still end up
blocking, at which point we would never end unblocking again, which
would result in LookupServer locking up as well.
This change unifies the naming convention for kernel tasks.
The goal of this change is to:
- Make the task names more descriptive, so users can more
easily understand their purpose in System Monitor.
- Unify the naming convention so they are consistent.
For the same reason we ignore interfaces without an IP address when
choosing where to send a route, we should also ignore interfaces without
IP addresses when updating the ARP table on incoming packets from
local addresses.
On an interface with a null address, the mask checking would always
result in zero, which resulted in the system updating the ARP table on
almost every incoming packet from any address (private or public).
This patch fixes this behavior by only applying this check to interfaces
with valid addresses and now the ARP table won't get constantly
hammered.
Closes#13713
Previously the routing table did not store the route flags. This
adds basic support and exposes them in the /proc directory so that a
userspace caller can query the route and identify the type of each
route.
It doesn't make sense after introduction of routing table which allows
having multiple gateways for every interface, and isn't used by any of
the userspace programs now.
Previously the system had no concept of assigning different routes for
different destination addresses as the default gateway IP address was
directly assigned to a network adapter. This default gateway was
statically assigned and any update would remove the previously existing
route.
This patch is a beginning step towards implementing #180. It implements
a simple global routing table that is referenced during the routing
process. With this implementation it is now possible for a user or
service (i.e. DHCP) to dynamically add routes to the table.
The routing table will select the most specific route when possible. It
will select any direct match between the destination and routing entry
addresses. If the destination address overlaps between multiple entries,
the Kernel will use the longest prefix match, or the longest number of
matching bits between the destination address and the routing address.
In the event that there is no entries found for a specific destination
address, this implementation supports entries for a default route to be
set for any specified interface.
This is a small first step towards enhancing the system's routing
capabilities. Future enhancements would include referencing a
configuration file at boot to load pre-defined static routes.
Instead, hold the lock while we copy the contents to a stack-based
Vector then iterate on it without any locking.
Because we rely on heap allocations, we need to propagate errors back
in case of OOM condition, therefore, both PCI::enumerate API function
and PCI::Access::add_host_controller_and_enumerate_attached_devices use
now a ErrorOr<void> return value to propagate errors. OOM Error can only
occur when enumerating the m_device_identifiers vector under a spinlock
and trying to expand the temporary Vector which will be used locklessly
to actually iterate over the PCI::DeviceIdentifiers objects.
