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75 commits

Author SHA1 Message Date
Andreas Kling
4e60551aec Rename Task to Process. 2018-11-01 13:10:12 +01:00
Andreas Kling
8525cdd6a2 Fix crash when process spawn fails. 2018-11-01 12:55:06 +01:00
Andreas Kling
0f70b9105f Implement address validation by querying the task's page directory.
This is way better than walking the region lists. I suppose we could
even let the hardware trigger a page fault and handle that. That'll
be the next step in the evolution here I guess.
2018-11-01 12:45:51 +01:00
Andreas Kling
f76fcd1e62 Do a bit less work in every context switch. 2018-11-01 11:57:36 +01:00
Andreas Kling
5891691640 Fix /proc/PID/stack in the new per-process page directory world.
I added an RAII helper called OtherTaskPagingScope. While present,
it switches the kernel over to using another task's page directory.
This is perfect for e.g walking the stack in /proc/PID/stack.
2018-11-01 11:44:21 +01:00
Andreas Kling
c45f166c63 More work on per-process page directories. It basically works now!
I spent some time stuck on a problem where processes would clobber each
other's stacks. Took me a moment to figure out that their stacks
were allocated in the sub-4MB linear address range which is shared
between all processes. Oops!
2018-11-01 11:36:25 +01:00
Andreas Kling
1da0a7c949 Give each task its own page directory.
This isn't finished but I'll commit as I go. We need to get to where context
switching only needs to change CR3 and everything's ready to go.

My basic idea is:
- The first 4 kB is off-limits. This catches null dereferences.
- Up to the 4 MB mark is identity-mapped and kernel-only.
- The rest is available to everyone!

While the first 4 MB is only available to the kernel, it's still mapped in
every process, for convenience when entering the kernel.
2018-11-01 09:01:51 +01:00
Andreas Kling
a685809e75 Waiters should be notified when a waitee is killed.
Ran into a horrendous bug where VirtualConsole would overrun its buffer
and scribble right into some other object if we were interrupted while
processing a character. Slapped an InterruptDisabler onto onChar for now.

This provokes an interesting question though.. if a process is killed
while its in kernel space, how the heck do we release any locks it held?
I'm sure there are many different solutions to this problem, but I'll
have to think about it.
2018-11-01 01:05:59 +01:00
Andreas Kling
9a086b2d35 Add a kmalloc_eternal() for things that will never be destroyed. 2018-10-31 23:19:15 +01:00
Andreas Kling
819ce91395 Enough compatibility work to make figlet build and run!
I ran out of steam writing library routines and imported two
BSD-licensed libc routines: sscanf() and getopt().

I will most likely rewrite them sooner or later. For now
I just wanted to see figlet running.
2018-10-31 17:52:59 +01:00
Andreas Kling
9160fd0d47 More LibC portability work while trying to get figlet building. 2018-10-31 10:14:56 +01:00
Andreas Kling
3218f00099 Implement basic sys$kill() and add a /bin/kill
All it can do right now is send SIGKILL which just murders the target task.
2018-10-31 01:06:57 +01:00
Andreas Kling
00c21d1590 Add sys$ttyname_r and ttyname_r() + ttyname().
And print a greeting when sh starts up so we know which TTY we're on.
2018-10-30 22:03:02 +01:00
Andreas Kling
7a7956a595 Virtual consoles kinda work!
We now make three VirtualConsoles at boot: tty0, tty1, and tty2.
We launch an instance of /bin/sh in each one.
You switch between them with Alt+1/2/3

How very very cool :^)
2018-10-30 15:33:37 +01:00
Andreas Kling
68739dc43e Start working on virtual consoles/TTYs.
This is a mess right now, but I'd rather commit as I go.
2018-10-30 13:59:29 +01:00
Andreas Kling
29035ffde7 Hang if a task crashes while it's already crashing.. 2018-10-30 00:12:08 +01:00
Andreas Kling
0f20be05a6 Implement sys$getcwd properly.
Also fixed broken strcpy that didn't copy the null terminator.
2018-10-30 00:06:31 +01:00
Andreas Kling
e6284a8774 Fix broken SpinLock.
The SpinLock was all backwards and didn't actually work. Fixing it exposed
how wrong most of the locking here is.

I need to come up with a better granularity here.
2018-10-29 22:04:26 +01:00
Andreas Kling
bea106fdb2 Fix up VFS::resolveSymbolicLink() to use a base inode instead of a base path.
Also more VFS error plumbing.
2018-10-28 14:25:51 +01:00
Andreas Kling
97726862dd Add basic symlink support.
- sys$readlink + readlink()
- Add a /proc/PID/exe symlink to the process's executable.
- Print symlink contents in ls output.
- Some work on plumbing options into VFS::open().
2018-10-28 14:11:51 +01:00
Andreas Kling
1d4af51250 Add a VFS::absolutePath(InodeIdentifier).
This is pretty inefficient for ext2fs. We walk the entire block group
containing the inode, searching through every directory for an entry
referencing this inode.

It might be a good idea to cache this information somehow. I'm not sure
how often we'll be searching for it.

Obviously there are multiple caching layers missing in the file system.
2018-10-28 12:20:25 +01:00
Andreas Kling
1d5afbdffc Add sys$set_mmap_name and use it from LibC's malloc.
It's nice to be able to identify mmap's in /proc/PID/vm.
2018-10-28 09:57:22 +01:00
Andreas Kling
e904f193c1 Canonicalize the path used by sh.
With a bunch of LibC work to support the feature. LibC now initializes
AK::StringImpl by default. It's now fine to use AK in LibC/Userland! :^)
2018-10-28 09:36:21 +01:00
Andreas Kling
8f91a47aeb Add some basic field width support to printf().
Use it to make "ls" output a bit better. Also sys$spawn now fails with EACCES
if the path is not a file that's executable by the current uid/gid.
2018-10-27 16:43:03 +02:00
Andreas Kling
9a71c7759a Implement loading of linked ELF executables.
This took me a couple hours. :^)

The ELF loading code now allocates a single region for the entire
file and creates virtual memory mappings for the sections as needed.

Very nice!
2018-10-27 14:56:52 +02:00
Andreas Kling
ec07761d0f Implement waitpid() support for getting the waitee's exit code. 2018-10-27 01:24:22 +02:00
Andreas Kling
3db8d7ae1a Use Unix::stat for sys$lstat(). 2018-10-27 00:29:31 +02:00
Andreas Kling
509e5f9952 Add some basic address validation to syscalls.
This is extremely ineffcient, but it doesn't really matter yet.
2018-10-27 00:29:24 +02:00
Andreas Kling
2716a9e2d7 Greatly improve /proc/PID/stack by tracing the ebp frame chain.
I also added a generator cache to FileHandle. This way, multiple
reads to a generated file (i.e in a synthfs) can transparently
handle multiple calls to read() without the contents changing
between calls.

The cache is discarded at EOF (or when the FileHandle is destroyed.)
2018-10-27 00:14:24 +02:00
Andreas Kling
c928b06218 Add a very hackish /proc/PID/stack.
It walks the stack and identifies anything that looks like a kernel symbol.
This could be a lot more sophisticated.
2018-10-26 22:33:15 +02:00
Andreas Kling
a32b3a3ddf Implement /proc/PID/vm.
Refactored SyntheticFileSystem to maintain an arbitrary directory structure.
ProcFileSystem creates a directory entry in /proc for each new process.
2018-10-26 17:44:19 +02:00
Andreas Kling
10347b9ae8 Add ASSERT_INTERRUPTS_DISABLED in Task::fromPID(). 2018-10-26 15:11:29 +02:00
Andreas Kling
1c45b28da6 Add sys$uname() and a /bin/uname utility. 2018-10-26 14:57:26 +02:00
Andreas Kling
384e2f24d4 Add per-task limit for open fd's. Hard-coded at 16 for now. 2018-10-26 14:30:38 +02:00
Andreas Kling
2749e7f1c2 Implement sys$chdir() and teach sh+ls to cd around and browse different dirs. 2018-10-26 14:24:11 +02:00
Andreas Kling
0af9254812 If spawning a task fails after we did a partial ELF load, remap current.
This is an annoying issue. It'd be nice if this code didn't have to worry
about preserving the calling task's mappings.
2018-10-26 12:22:22 +02:00
Andreas Kling
df87dda63c Implement argc/argv support for spawned tasks.
Celebrate the new functionality with a simple /bin/cat implementation. :^)
2018-10-26 11:16:56 +02:00
Andreas Kling
53abfa7ea1 Add sys$gethostname and /bin/hostname 2018-10-26 09:54:29 +02:00
Andreas Kling
dc6f57f19c Add gettimeofday() syscall and LibC wrappers gettimeofday() and time().
This only has second accuracy right now, I'll work out subseconds later.
2018-10-25 17:36:18 +02:00
Andreas Kling
5978185242 Add a "sleep" syscall that sleeps for N seconds. 2018-10-25 13:56:03 +02:00
Andreas Kling
c6f2890d8e Implement a basic way for read() to block.
FileHandle gets a hasDataAvailableForRead() getter.
If this returns true in sys$read(), the task will block(BlockedRead) + yield.
The fd blocked on is stored in Task::m_fdBlockedOnRead.
The scheduler then looks at the state of that fd during the unblock phase.

This makes "sh" restful. :^)

There's still some problem with the kernel not surviving the colonel task
getting scheduled. I need to figure that out and fix it.
2018-10-25 13:09:56 +02:00
Andreas Kling
ba56f4afde If no context switch occurs, add 1 to the timesScheduled() for current.
This seems like more accurate accounting.
2018-10-25 12:45:29 +02:00
Andreas Kling
260b14e505 Implement errno in LibC.
This also meant I had to implement BSS (SHT_NOBITS) sections in ELFLoader.
I also added an strerror() so we can print out what the errors are.
2018-10-25 12:06:50 +02:00
Andreas Kling
434b6a8688 Unify the Task constructors.
There's now Task::create() and Task::createKernelTask().
2018-10-25 11:17:47 +02:00
Andreas Kling
de7c54545a Remove age-old IPC stuff that wasn't working anyway.
I'll make a fresh start with IPC code when I get there.
2018-10-25 10:39:39 +02:00
Andreas Kling
ce126120d1 Add a few more InterruptDisablers. 2018-10-25 10:33:10 +02:00
Andreas Kling
16f318408d ELFLoader should fail with an error message for unresolved symbols. 2018-10-25 10:02:04 +02:00
Andreas Kling
ec1d16b307 Add a "pwd" utility to userland.
It's implemented as a separate process. How cute is that.
Tasks now have a current working directory. Spawned tasks inherit their
parent task's working directory.
Currently everyone just uses "/" as there's no way to chdir().
2018-10-24 14:28:22 +02:00
Andreas Kling
5f36a5f22e Add an lstat() syscall and use it to make "ls" nicer. 2018-10-24 13:19:36 +02:00
Andreas Kling
bca4b71bfa Lots of hacking to make a very simple "ls" utility.
I added a dead-simple malloc that only allows allocations < 4096 bytes.
It just forwards the request to mmap() every time.

I also added simplified versions of opendir() and readdir().
2018-10-24 12:50:07 +02:00