This file refers to the controlling terminal associated with the current
process. It's specified by POSIX, and is used by ports like openssh to
interface with the terminal even if the standard input/output is
redirected to somewhere else.
Our implementation leverages ProcFS's existing facilities to create
process-specific symbolic links. In our setup, `/dev/tty` is a symbolic
link to `/proc/self/tty`, which itself is a symlink to the appropriate
`/dev/pts` entry. If no TTY is attached, `/dev/tty` is left dangling.
Now that the userland has a compatiblity wrapper for select(), the
kernel doesn't need to implement this syscall natively. The poll()
interface been around since 1987, any code still using select()
should be slapped silly.
Note: the SerenityOS source tree mostly uses select() and not poll()
despite SerenityOS having support for poll() since early 2019...
This includes a new Thread::Blocker called SignalBlocker which blocks
until a signal of a matching type is pending. The current Blocker
implementation in the Kernel is very complicated, but cleaning it up is
a different yak for a different day.
This allows userspace to trigger a full (FIXME) flush of a shared file
mapping to disk. We iterate over all the mapped pages in the VMObject
and write them out to the underlying inode, one by one. This is rather
naive, and there's lots of room for improvement.
Note that shared file mappings are currently not possible since mmap()
returns ENOTSUP for PROT_WRITE+MAP_SHARED. That restriction will be
removed in a subsequent commit. :^)
This isn't a complete conversion to ErrorOr<void>, but a good chunk.
The end goal here is to propagate buffer allocation failures to the
caller, and allow the use of TRY() with formatting functions.
... In files included from Kernel/Thread.cpp or Kernel/Process.cpp
Some places the warning is suppressed, because we do not want a const
object do have non-const access to the returned sub-object.
`off_t` is a 64-bit signed integer, so passing it in a register on i686
is not the best idea.
This fix gets us one step closer to making the LLVM port work.
Instead of signalling allocation failure with a bool return value
(false), we now use ErrorOr<void> and return ENOMEM as appropriate.
This allows us to use TRY() and MUST() with Vector. :^)
In particular, fstatvfs used to assume that a file that was earlier
opened using some path will forever be at that path. This is wrong, and
in the meantime new mounts and new filesystems could take up the
filename or directories, leading to a completely inaccurate result.
This commit improves the situation:
- All filesystem information is now always accurate.
- The mount flags *might* be erroneously zero, if the custody for the
open file is not available. I don't know when that might happen, but
it is definitely not the typical case.
We now use AK::Error and AK::ErrorOr<T> in both kernel and userspace!
This was a slightly tedious refactoring that took a long time, so it's
not unlikely that some bugs crept in.
Nevertheless, it does pass basic functionality testing, and it's just
real nice to finally see the same pattern in all contexts. :^)
The OpenFileDescription class already offers the necessary functionlity,
so implementing this was only a matter of following the structure for
`read` while handling the additional `offset` argument.
This change removes the halt and reboot syscalls, and create a new
mechanism to change the power state of the machine.
Instead of how power state was changed until now, put a SysFS node as
writable only for the superuser, that with a defined value, can result
in either reboot or poweroff.
In the future, a power group can be assigned to this node (which will be
the GroupID responsible for power management).
This opens an opportunity to permit to shutdown/reboot without superuser
permissions, so in the future, a userspace daemon can take control of
this node to perform power management operations without superuser
permissions, if we enforce different UserID/GroupID on that node.
These interfaces are broken for about 9 months, maybe longer than that.
At this point, this is just a dead code nobody tests or tries to use, so
let's remove it instead of keeping a stale code just for the sake of
keeping it and hoping someone will fix it.
To better justify this, I read that OpenBSD removed loadable kernel
modules in 5.7 release (2014), mainly for the same reason we do -
nobody used it so they had no good reason to maintain it.
Still, OpenBSD had LKMs being effectively working, which is not the
current state in our project for a long time.
An arguably better approach to minimize the Kernel image size is to
allow dropping drivers and features while compiling a new image.
This patch converts all the usage of AK::String around sys$execve() to
using KString instead, allowing us to catch and propagate OOM errors.
It also required changing the kernel CommandLine helper class to return
a vector of KString for the userspace init program arguments.
Make use of the new FileDescription::try_serialize_absolute_path() to
avoid String in favor of KString throughout much of sys$execve() and
its helpers.
We previously allowed Thread to exist in a state where its m_name was
null, and had to work around that in various places.
This patch removes that possibility and forces those who would create a
thread (or change the name of one) to provide a NonnullOwnPtr<KString>
with the name.
The default template argument is only used in one place, and it
looks like it was probably just an oversight. The rest of the Kernel
code all uses u8 as the type. So lets make that the default and remove
the unused template argument, as there doesn't seem to be a reason to
allow the size to be customizable.
Instead of checking it at every call site (to generate EBADF), we make
file_description(fd) return a KResultOr<NonnullRefPtr<FileDescription>>.
This allows us to wrap all the calls in TRY(). :^)
The only place that got a little bit messier from this is sys$mount(),
and there's a whole bunch of things there in need of cleanup.
This is the idiomatic way to declare type aliases in modern C++.
Flagged by Sonar Cloud as a "Code Smell", but I happen to agree
with this particular one. :^)
This function is currently only ever used to create the init process
(SystemServer). It had a few idiosyncratic things about it that this
patch cleans up:
- Errors were returned in an int& out-param.
- It had a path for non-0 process PIDs which was never taken.
REQUIRE_PROMISE and REQUIRE_NO_PROMISES were macros for some reason,
and used all over the place.
This patch adds require_promise(Pledge) and require_no_promises()
to Process and makes the macros call these on the current process
instead of inlining code everywhere.
Prior to this change, both uid_t and gid_t were typedef'ed to `u32`.
This made it easy to use them interchangeably. Let's not allow that.
This patch adds UserID and GroupID using the AK::DistinctNumeric
mechanism we've already been employing for pid_t/ProcessID.
