This should allow us to eventually properly saturate high-bandwidth
network links when using TCP, once other nonoptimal parts of our
network stack are improved.
Instead of lying and claiming we always have space left in our receive
buffer, actually report the available space.
While this doesn't really affect network-bound workloads, it makes a
world of difference in cpu/disk-bound ones, like git clones. Resulting
in a considerable speed-up, and in some cases making them work at all.
(instead of the sender side hanging up the connection due to timeouts)
Previously we would incorrectly handle the (somewhat uncommon) case of
binding and then separately connecting a tcp socket to a server, as we
would register the socket during the manual bind(2) in the sockets by
tuple table, but our effective tuple would then change as the result of
the connect updating our target peer address. This would result in the
the entry not being removed from the table on destruction, which could
lead to a UAF.
We now make sure to update the table entry if needed during connects.
POSIX (rightfully so) specifies that the sendto address argument is
ignored in connection-oriented protocols.
The TCPSocket also assumed the peer address may not change post-connect
and would trigger a UAF in sockets_by_tuple() when it did.
POSIX requires that broadcast sends will only be allowed if the
SO_BROADCAST socket option was set on the socket.
Also, broadcast sends to protocols that do not support broadcast (like
TCP), should always fail.
Since the POSIX sigaltstack manpage suggests allocating the stack
region using malloc(), and many heap implementations (including ours)
store heap chunk metadata in memory just before the vended pointer,
we would end up zeroing the metadata, leading to various crashes.
In a bunch of cases, this actually ends up simplifying the code as
to_number will handle something such as:
```
Optional<I> opt;
if constexpr (IsSigned<I>)
opt = view.to_int<I>();
else
opt = view.to_uint<I>();
```
For us.
The main goal here however is to have a single generic number conversion
API between all of the String classes.
Our existing AnonymousVMObject cloning flow contains an optimization
wherein purgeable VMObjects which are marked volatile during the clone
are created as a new zero-filled VMObject (as if it was purged), which
lets us skip the expensive COW process.
Unfortunately, one crucial part was missing: Marking the cloned region
as purged, (which is the value returned from madvise when unmarking the
region as volatile) so the userland logic was left unaware of the
effective zero-ing of their memory region, resulting in odd behaviour
and crashes in places like our malloc's large allocation support.
The signal handling code (and possibly other code as well) expects this
struct to have an alignment of 16 bytes, as it pushes this struct on the
stack.
MasterPTY::read called DoubleBuffer::read which takes a mutex (which
may block) while holding m_slave's spinlock. If it did block, and was
later rescheduled on a different physical CPU, we would deadlock on
re-locking m_slave inside the unblock callback. (Since our recursive
spinlock implementation is processor based and not process based)
MasterPTY's double buffer unblock callback would take m_slave's
spinlock and then call evaluate_block_conditions() which would take
BlockerSet's spinlock, while on the other hand, BlockerSet's
add_blocker would take BlockerSet's spinlock, and then call
should_add_blocker, which would call unblock_if_conditions_are_met,
which would then call should_unblock, which will finally call
MasterPTY::can_read() which will take m_slave's spinlock.
Resolve this by moving the call to evaluate_block_conditions() out of
the scope of m_slave's spinlock, as there's no need to hold the lock
while calling it anyways.
If there's no loadable segments then there can't be any code to execute
either. This resolves a crash these kinds of ELF files would cause from
the directly following VERIFY statement.
Previously we would unintentionally leave them zero-initialized,
resulting in any threads created post fork (but without execve) having
invalid thread local storage pointers stored in their FS register.
This commit adds all necessary includes, so all functions are properly
declared.
PCI.cpp is moved to PCI/Initializer.cpp, as that matches the header
path.
The `[[gnu::packed]]` attribute apparently lowered the required
alignment of the structs, which caused the compiler to generate two
1 byte loads/stores on RISC-V. This caused the kernel to read/write
incorrect values, as the device only seems to accept 2 byte operations.
`MM.protect_kernel_image` would otherwise make the contents of these
sections read-only, as they were for some reason placed before `.data`
and after the start of `.text`.
RAMFS was passing 0, which lead to the userspace seeing all entries as
DT_UNKNOWN when iterating over the directory contents.
To repro prior to this commit, simply check `echo /tmp/*/`.
Following 77441079dd, the code in Kernel/Devices/HID/MouseDevice.cpp
is used by both USB and PS2 rodents. Make sure not to emit misleading
debug messages that could suggest that a USB mouse is a PS/2 one.
Other arches don't use the prekernel, so don't try to unmap it on
non-x86 platforms.
For some reason, this didn't cause aarch64 to crash, but on riscv64 this
would cause a panic.
This doesn't affect system functionality, but somewhat reduces the
reliance on complicated hardcoded paths. It also allows the user to
simply link /init (which is normally a symbolic link) to another program
to run it instead of SystemServer as the default option.
We could technically copy the dynamic loader to other path and run it
from there, so let's not assume paths.
If the user is so determined to do such thing, then a warning is quite
meaningless.
When writing to /sys/kernel/request_panic it will do a kernel panic.
Trying to truncate the node will result in kernel panic with a slightly
different message.
The networking subsystem currently assumes all adapters are Ethernet
adapters, including the LoopbackAdapter, so all packets are pre-pended
with an Ethernet Frame header. Since the MTU must not include any
overhead added by the data-link (Ethernet in this case) or physical
layers, we need to subtract it from the MTU.
This fixes a kernel panic which occurs when sending a packet that is at
least 65523 bytes long through the loopback adapter, which results in
the kernel "receiving" a packet which is larger than the support MTU
out the other end. (As the actual final size was increased by the
addition of the ethernet frame header)
As per POSIX, the behavior of listen() with a backlog value of 0 is
implementation defined: "A backlog argument of 0 may allow the socket
to accept connections, in which case the length of the listen queue may
be set to an implementation-defined minimum value."
Since creating a socket that can't accept any connections seems
relatively useless, and as other platforms (Linux, FreeBSD, etc) chose
to support accepting connections with this backlog value, support it as
well by normalizing it to 1.
This is necessary for being able to use the qemu `-kernel` option.
The QEMU virt machine uses OpenSBI's FW_DYNAMIC feature to pass
the kernel entry address, which is the virtual entry point address
specified in the kernel ELF. If we instead `objcopy` the kernel into a
raw binary, OpenSBI will jump to the physical kernel load address, which
is what we want it to do.
When the FileSystem does a sync, it gathers up all the inodes with
dirty metadata into a vector. The inode mutex is not held while
checking the inode dirty bit, which can lead to a kernel panic
due to concurrent inode modifications.
Fixes: #21796
