Commit Graph

21 Commits

Author SHA1 Message Date
Justin
2d098c88dc Kernel: Implement peek() function for DoubleBuffer
This allows us to "peek" into a DoubleBuffer without incrementing
the m_read_buffer_index, which is needed to implement MSG_PEEK.
2021-04-29 08:09:53 +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
Andreas Kling
5d180d1f99 Everywhere: Rename ASSERT => VERIFY
(...and ASSERT_NOT_REACHED => VERIFY_NOT_REACHED)

Since all of these checks are done in release builds as well,
let's rename them to VERIFY to prevent confusion, as everyone is
used to assertions being compiled out in release.

We can introduce a new ASSERT macro that is specifically for debug
checks, but I'm doing this wholesale conversion first since we've
accumulated thousands of these already, and it's not immediately
obvious which ones are suitable for ASSERT.
2021-02-23 20:56:54 +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
Andreas Kling
7a3ab6c517 Kernel: Make File::write() and File::read() return KResultOr<size_t>
Instead of returning a ssize_t where negative values mean error,
we now return KResultOr<size_t> and use the error state to report
errors exclusively.
2020-08-04 18:17:16 +02:00
Andreas Kling
a356e48150 Kernel: Move all code into the Kernel namespace 2020-02-16 01:27:42 +01:00
Andreas Kling
f4f958f99f Kernel: Make DoubleBuffer use a KBuffer instead of kmalloc()ing
Background: DoubleBuffer is a handy buffer class in the kernel that
allows you to keep writing to it from the "outside" while the "inside"
reads from it. It's used for things like LocalSocket and TTY's.
Internally, it has a read buffer and a write buffer, but the two will
swap places when the read buffer is exhausted (by reading from it.)

Before this patch, it was internally implemented as two Vector<u8>
that we would swap between when the reader side had exhausted the data
in the read buffer. Now instead we preallocate a large KBuffer (64KB*2)
on DoubleBuffer construction and use that throughout its lifetime.

This removes all the kmalloc heap traffic caused by DoubleBuffers :^)
2020-01-20 16:08:49 +01:00
Andreas Kling
94ca55cefd Meta: Add license header to source files
As suggested by Joshua, this commit adds the 2-clause BSD license as a
comment block to the top of every source file.

For the first pass, I've just added myself for simplicity. I encourage
everyone to add themselves as copyright holders of any file they've
added or modified in some significant way. If I've added myself in
error somewhere, feel free to replace it with the appropriate copyright
holder instead.

Going forward, all new source files should include a license header.
2020-01-18 09:45:54 +01:00
Andreas Kling
ec65b8db2e Revert "Kernel: Make DoubleBuffer use a KBuffer instead of kmalloc()ing"
This reverts commit 1cca5142af.

This appears to be causing intermittent triple-faults and I don't know
why yet, so I'll just revert it to keep the tree in decent shape.
2019-10-18 15:58:06 +02:00
Andreas Kling
1cca5142af Kernel: Make DoubleBuffer use a KBuffer instead of kmalloc()ing
Background: DoubleBuffer is a handy buffer class in the kernel that
allows you to keep writing to it from the "outside" while the "inside"
reads from it. It's used for things like LocalSocket and PTY's.
Internally, it has a read buffer and a write buffer, but the two will
swap places when the read buffer is exhausted (by reading from it.)

Before this patch, it was internally implemented as two Vector<u8>
that we would swap between when the reader side had exhausted the data
in the read buffer. Now instead we preallocate a large KBuffer (64KB*2)
on DoubleBuffer construction and use that throughout its lifetime.

This removes all the kmalloc heap traffic caused by DoubleBuffers :^)
2019-10-18 14:55:04 +02:00
Andreas Kling
27f699ef0c AK: Rename the common integer typedefs to make it obvious what they are.
These types can be picked up by including <AK/Types.h>:

* u8, u16, u32, u64 (unsigned)
* i8, i16, i32, i64 (signed)
2019-07-03 21:20:13 +02:00
Andreas Kling
c3b7ace3e0 Kernel: Assign Lock names in class member initializers. 2019-05-02 03:28:20 +02:00
Andreas Kling
313ee8dd19 Move Lock from AK to Kernel, since it only works inside the kernel. 2019-03-16 13:18:22 +01:00
Andreas Kling
beda478821 Kernel: Make syscalls that take a buffer size use ssize_t instead of size_t.
Dealing with the unsigned overflow propagation here just seems unreasonably
error prone. Let's limit ourselves to 2GB buffer sizes instead.
2019-02-25 21:21:12 +01:00
Andreas Kling
5582a0a254 Kernel: When a lock is busy, donate remaining process ticks to lock holder.
Since we know who's holding the lock, and we're gonna have to yield anyway,
we can just ask the scheduler to donate any remaining ticks to that process.
2019-02-07 11:14:58 +01:00
Andreas Kling
e9e57c5f65 Rename SpinLock to Lock. It hasn't been a SpinLock for some time.
I'm pretty happy with the mechanism of AK::Lock for now.
2019-01-17 16:25:02 +01:00
Andreas Kling
52c004eb53 Add internal locking to DoubleBuffer. 2019-01-15 21:43:38 +01:00
Andreas Kling
e452303c66 Allow character devices to block write attempts until there is more space. 2019-01-15 09:17:22 +01:00
Andreas Kling
ec1c487dcd Yet another pass of style fixes. 2018-12-21 02:10:45 +01:00
Andreas Kling
bbfae19238 Move DoubleBuffer to its own files. 2018-12-03 01:51:44 +01:00