This patch makes it possible to make memory regions non-readable.
This is enforced using the "present" bit in the page tables.
A process that hits an not-present page fault in a non-readable
region will be crashed.
This patch introduces code generation for the WindowServer IPC with
its clients. The client/server endpoints are defined by the two .ipc
files in Servers/WindowServer/: WindowServer.ipc and WindowClient.ipc
It now becomes significantly easier to add features and capabilities
to WindowServer since you don't have to know nearly as much about all
the intricate paths that IPC messages take between LibGUI and WSWindow.
The new system also uses significantly less IPC bandwidth since we're
now doing packed serialization instead of passing fixed-sized structs
of ~600 bytes for each message.
Some repaint coalescing optimizations are lost in this conversion and
we'll need to look at how to implement those in the new world.
The old CoreIPC::Client::Connection and CoreIPC::Server::Connection
classes are removed by this patch and replaced by use of ConnectionNG,
which will be renamed eventually.
Goodbye, old WindowServer IPC. You served us well :^)
This patch adds these I/O counters to each thread:
- (Inode) file read bytes
- (Inode) file write bytes
- Unix socket read bytes
- Unix socket write bytes
- IPv4 socket read bytes
- IPv4 socket write bytes
These are then exposed in /proc/all and seen in SystemMonitor.
Instead of using the generic block mechanism, wait-queued threads now
go into the special Queued state.
This fixes an issue where signal dispatch would unblock a wait-queued
thread (because signal dispatch unblocks blocked threads) and cause
confusion since the thread only expected to be awoken by the queue.
Instead of waking up repeatedly to check if a disk operation has
finished, use a WaitQueue and wake it up in the IRQ handler.
This simplifies the device driver a bit, and makes it more responsive
as well :^)
There was a race window between instantiating a WaitQueueBlocker and
setting the thread state to Blocked. If a thread was preempted between
those steps, someone else might try to wake the wait queue and find an
unblocked thread in a wait queue, which is not sane.
The kernel's Lock class now uses a proper wait queue internally instead
of just having everyone wake up regularly to try to acquire the lock.
We also keep the donation mechanism, so that whenever someone tries to
take the lock and fails, that thread donates the remainder of its
timeslice to the current lock holder.
After unlocking a Lock, the unlocking thread calls WaitQueue::wake_one,
which unblocks the next thread in queue.
Kernel modules can now be unloaded via a syscall. They get a chance to
run some code of course. Before deallocating them, we call their
"module_fini" symbol.
It's now possible to load a .o file into the kernel via a syscall.
The kernel will perform all the necessary ELF relocations, and then
call the "module_init" symbol in the loaded module.
This defaults to 1500 for all adapters, but LoopbackAdapter increases
it to 65536 on construction.
If an IPv4 packet is larger than the MTU, we'll need to break it into
smaller fragments before transmitting it. This part is a FIXME. :^)
Turns out we can use abi::__cxa_demangle() for this, and all we need to
provide is sprintf(), realloc() and free(), so this patch exposes them.
We now have fully demangled C++ backtraces :^)
The fault was happening when retrieving a current backtrace for the
SystemServer process.
To generate a backtrace, we go into the paging scope of the process,
meaning we temporarily switch to using its page directory as our own.
Because kernel VM is allocated on demand, it's possible for a process's
mappings above the 3GB mark to be out-of-date. Normally this just gets
fixed up transparently by the page fault handler (which simply copies
the PDE from the canonical MM.kernel_page_directory() into the current
process.)
However, if the current kernel *stack* is in a piece of memory that
the backtraced process lacks up-to-date PDE's for, we still get a page
fault, but are unable to handle it, since the CPU wants to push to the
stack as part of calling the page fault handler. So we're screwed and
it's a triple-fault.
Fix this by always updating the kernel VM mappings before switching
into a paging scope. In practical terms, this is a 1KB memcpy() that
happens when generating a backtrace, or doing exec().
Previously it was not possible to see what each thread in a process was
up to, or how much CPU it was consuming. This patch fixes that.
SystemMonitor and "top" now show threads instead of just processes.
"ps" is gonna need some more fixing, but it at least builds for now.
Fixes#66.
Then only allow regions with that bit to be manipulated via munmap()
and mprotect(). This prevents messing with non-mmap()ed regions in
a process's address space (stacks, shared buffers, ...)
This patch adds ProtocolServer, a server that handles network requests
on behalf of its clients. The first protocol implemented is HTTP.
The idea here is to use a plug-in architecture where any number of
protocols can be added and implemented without having to mess around
with each client program that wants to use the protocol.
A simple client API is provided through LibProtocol::Client. :^)
The kernel is now no longer identity mapped to the bottom 8MiB of
memory, and is now mapped at the higher address of `0xc0000000`.
The lower ~1MiB of memory (from GRUB's mmap), however is still
identity mapped to provide an easy way for the kernel to get
physical pages for things such as DMA etc. These could later be
mapped to the higher address too, as I'm not too sure how to
go about doing this elegantly without a lot of address subtractions.
This adds a call to set_metadata_dirty(true) to
Ext2FS::write_directory(). This fixes a bug wherein InodeWatchers
weren't alerted on directory updates.
Remove explicit checking for pending signals from writing code paths,
since this is handled automatically when blocking, and should not
happen if the write() call is "short", i.e. doesn't block. All the
other syscalls already work like this.
Fixes https://github.com/SerenityOS/serenity/issues/797
After a socket has disconnected, we shouldn't return -EAGAIN. Instead
we should allow userspace to read/recvfrom the socket until its packet
queue has been exhausted.
At that point, we now return 0, signalling EOF.
It might be even better to start returning -ENOTCONN after signalling
EOF once. I'm not sure how that should work, needs looking into.
Instead of trying to build the host-side code generator helpers right
before we need them in the LibHTML build process, just build them ahead
of time in makeall.sh, like we already do for {IPC,Form}Compiler.
This is a bit gentler than jumping to 0x0, which always crashes the
whole process. Also log a debug message about what happened, and let
the user know that it's probably time to rebuild the program.
