This should catch more malformed ELF files earlier than simply
checking the ELF header alone. Also change the API of
validate_program_headers to take the interpreter_path by pointer. This
makes it less awkward to call when we don't care about the interpreter,
and just want the validation.
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.
New Thread objects should be adopted into a RefPtr upon creation.
If creating a thread failed (e.g. out of memory), releasing the RefPtr
will destruct the partially created object, but in the successful case
the thread will add an additional reference that it keeps until it
finishes execution. Adopting will drop it to 1 when returning from
create_thread, or 0 if the thread could not be fully constructed.
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.
This adds the ability to pass a pointer to kernel thread/process.
Also add the ability to use a closure as thread function, which
allows passing information to a kernel thread more easily.
Use the TimerQueue to expire blocking operations, which is one less thing
the Scheduler needs to check on every iteration.
Also, add a BlockTimeout class that will automatically handle relative or
absolute timeouts as well as overriding timeouts (e.g. socket timeouts)
more consistently.
Also, rework the TimerQueue class to be able to fire events from
any processor, which requires Timer to be RefCounted. Also allow
creating id-less timers for use by blocking operations.
Rather than waiting until we get the first mouse packet, enable the
absolute mode immediately. This avoids having to click first to be
able to move the mouse.
We need to not only add a record for a reference, but we need
to copy the reference count on fork as well, because the code
in the fork assumes that it has the same amount of references,
still.
Also, once all references are dropped when a process is disowned,
delete the shared buffer.
Fixes#4076
This makes misses in the BlockBasedFS's LRU block cache faster by
storing the cache entries in one of two doubly-linked list.
Dirty and clean cache entries are kept in two separate lists, and
move between them when their state changes. This can probably be
improved upon further.
If the inode's block list cache is empty, we forgot to assign the
result of computing the block list. The fact that this worked anyway
makes me wonder when we actually don't have a cache..
Thanks to szyszkienty for spotting this! :^)
Instead of doing a linear scan of the entire cache when doing a lookup,
we now have a nice O(1) HashMap in front of the cache.
The cache miss case can still be improved, this patch really only helps
the cache hit case.
This dramatically improves cached filesystem I/O. :^)
Since we're using UserOrKernelBuffers, SMAP will be automatically
disabled when we actually access the buffer later on. There's no need
to disable it wholesale across the entire read/write operations.
This is a new "browse" permission that lets you open (and subsequently list
contents of) directories underneath the path, but not regular files or any other
types of files.
We should never resume a thread by directly setting it to Running state.
Instead, if a thread was in Running state when stopped, record the state
as Runnable.
Fixes#4150
We were leaking a ref on the executed inode in successful calls to
sys$execve(). This meant that once a binary had ever been executed,
it was impossible to remove it from the file system.
The execve system call is particularly finicky since the function
does not return normally on success, so extra care must be taken to
ensure nothing is kept alive by stack variables.
There is a big NOTE comment about this, and yet the bug still got in.
It would be nice to enforce this, but I'm unsure how.
e2fsck was complaining about blocks being allocated in an inode's list
of direct blocks while at the same time being free in the block bitmap.
It was easy to reproduce by creating a file with non-zero length and
then truncating it. This fixes the issue by clearing out the direct
block list when resizing a file to 0.
We need to create a reference for the new PID for each shared buffer
that the process had a reference to. If the process subsequently
get replaced through exec, those references will be dropped again.
But if exec for some reason fails then other code, such as global
destructors could still expect having access to them.
Fixes#4076
The time returned by sys$clock_gettime() was not aligned with the delay
calculations in sys$clock_nanosleep(). This patch fixes that by taking
the system's ticks_per_second value into account in both functions.
This patch also removes the need for Thread::sleep_until() and uses
Thread::sleep() for both absolute and relative sleeps.
This was causing the nesalizer emulator port to sleep for a negative
amount of time at the end of each frame, making it run way too fast.
Problem:
- C-style arrays do not automatically provide bounds checking and are
less type safe overall.
- `__builtin_memcmp` is not a constant expression in the current gcc.
Solution:
- Change private m_data to be AK::Array.
- Eliminate constructor from C-style array.
- Change users of the C-style array constructor to use the default
constructor.
- Change `operator==()` to be a hand-written comparison loop and let
the optimizer figure out to use `memcmp`.
We won't be receiving full PS/2 mouse packets when the VMWareBackdoor
absolute mouse mode is enabled. So, read just one byte every time
and retrieve the latest mouse packet from VMWareBackdoor immediately.
Fixes#4086
This allows issuing asynchronous requests for devices and waiting
on the completion of the request. The requests can cascade into
multiple sub-requests.
Since IRQs may complete at any time, if the current process is no
longer the same that started the process, we need to swich the
paging context before accessing user buffers.
Change the PATA driver to use this model.
Rework the PS/2 keyboard and mouse drivers to use a common 8042
controller driver. Also, reset and reconfigure the 8042 controller
as they are not guaranteed to be in the state that we expect.
When two processors send each others a SMP message at the same time
they need to process messages while waiting for delivery of the
message they just sent, or they will deadlock.
This makes most operations thread safe, especially so that they
can safely be used in the Kernel. This includes obtaining a strong
reference from a weak reference, which now requires an explicit
call to WeakPtr::strong_ref(). Another major change is that
Weakable::make_weak_ref() may require the explicit target type.
Previously we used reinterpret_cast in WeakPtr, assuming that it
can be properly converted. But WeakPtr does not necessarily have
the knowledge to be able to do this. Instead, we now ask the class
itself to deliver a WeakPtr to the type that we want.
Also, WeakLink is no longer specific to a target type. The reason
for this is that we want to be able to safely convert e.g. WeakPtr<T>
to WeakPtr<U>, and before this we just reinterpret_cast the internal
WeakLink<T> to WeakLink<U>, which is a bold assumption that it would
actually produce the correct code. Instead, WeakLink now operates
on just a raw pointer and we only make those constructors/operators
available if we can verify that it can be safely cast.
In order to guarantee thread safety, we now use the least significant
bit in the pointer for locking purposes. This also means that only
properly aligned pointers can be used.
Most systems (Linux, OpenBSD) adjust 0.5 ms per second, or 0.5 us per
1 ms tick. That is, the clock is sped up or slowed down by at most
0.05%. This means adjusting the clock by 1 s takes 2000 s, and the
clock an be adjusted by at most 1.8 s per hour.
FreeBSD adjusts 5 ms per second if the remaining time adjustment is
>= 1 s (0.5%) , else it adjusts by 0.5 ms as well. This allows adjusting
by (almost) 18 s per hour.
Since Serenity OS can lose more than 22 s per hour (#3429), this
picks an adjustment rate up to 1% for now. This allows us to
adjust up to 36s per hour, which should be sufficient to adjust
the clock fast enough to keep up with how much time the clock
currently loses. Once we have a fancier NTP implementation that can
adjust tick rate in addition to offset, we can think about reducing
this.
adjtime is a bit old-school and most current POSIX-y OSs instead
implement adjtimex/ntp_adjtime, but a) we have to start somewhere
b) ntp_adjtime() is a fairly gnarly API. OpenBSD's adjfreq looks
like it might provide similar functionality with a nicer API. But
before worrying about all this, it's probably a good idea to get
to a place where the kernel APIs are (barely) good enough so that
we can write an ntp service, and once we have that we should write
a way to automatically evaluate how well it keeps the time adjusted,
and only then should we add improvements ot the adjustment mechanism.
This addresses the issue first enountered in #3644. If a path is
first unveiled with "c" permissions, we should NOT return ENOENT
if the node does not exist on the disk, as the program will most
likely be creating it at a later time.
When computing the list of blocks to deallocate when freeing an inode,
we would stop collecting blocks after reaching the inode's block count.
Since we're getting rid of the inode, we need to also include the meta
blocks used by the on-disk block list itself.
