To be able to do this, we add a new class called CustodyBase, which can
be resolved on-demand internally in the VirtualFileSystem resolving path
code.
When being resolved, CustodyBase will return a known custody if it was
constructed with such, if that's not the case it will provide the root
custody if the original path is absolute.
Lastly, if that's not the case as well, it will resolve the given dirfd
to provide a Custody object.
This is a large commit because it implements a lot of stuff to make
add_child simpler to get working. This allows us to create new files
on a FAT partition.
This is the first part of write support, it allows for full file
modification, but no creating or removing files yet.
Co-Authored-By: implicitfield <114500360+implicitfield@users.noreply.github.com>
Caching the cluster list allows us to fill the two fields in the
InodeMetadata. While at it, don't cache the metadata as when we
have write support having to keep both InodeMetadata and FATEntry
correct is going to get very annoying.
dbgln() will always take its arguments by reference when possible, which
causes UB when dealing with packed structs. To avoid this, we now
explicitly copy all members whose alignment requirements aren't met.
These changes are compatible with clang-format 16 and will be mandatory
when we eventually bump clang-format version. So, since there are no
real downsides, let's commit them now.
Either we mount from a loop device or other source, the user might want
to obfuscate the given source for security reasons, so this option will
ensure this will happen.
If passed during a mount, the source will be hidden when reading from
the /sys/kernel/df node.
Similarly to DevPtsFS, this filesystem is about exposing loop device
nodes easily in /dev/loop, so userspace doesn't need to do anything in
order to use new devices immediately.
Instead of returning a raw pointer, which could be technically invalid
when using it in the caller function, we return a valid RefPtr of such
device.
This ensures that the code in DevPtsFS is now safe from a rare race
condition in which the SlavePTY device is gone but we still have a
pointer to it.
This device is a block device that allows a user to effectively treat an
Inode as a block device.
The static construction method is given an OpenFileDescription reference
but validates that:
- The description has a valid custody (so it's not some arbitrary file).
Failing this requirement will yield EINVAL.
- The description custody points to an Inode which is a regular file, as
we only support (seekable) regular files. Failing this requirement
will yield ENOTSUP.
LoopDevice can be used to mount a regular file on the filesystem like
other supported types of (physical) block devices.
Such operation is almost equivalent to writing on an Inode, so lock the
Inode m_inode_lock exclusively.
All FileSystem Inode implementations then override a new method called
truncate_locked which should implement the actual truncating.
SysFS, ProcFS and DevPtsFS were all sending filetype 0 when traversing
their directories, but it is actually very easy to send proper filetypes
in these filesystems.
This patch binds all RAM backed filesystems to use only one enum for
their internal filetype, to simplify the implementation and allow
sharing of code.
Please note that the Plan9FS case is currently not solved as I am not
familiar with this filesystem and its constructs.
The ProcFS mostly keeps track of the filetype, and a fix was needed for
the /proc root directory - all processes exhibit a directory inside it
which makes it very easy to hardcode the directory filetype for them.
There's also the `self` symlink inode which is now exposed as DT_LNK.
As for SysFS, we could leverage the fact everything inherits from the
SysFSComponent class, so we could have a virtual const method to return
the proper filetype.
Most of the files in SysFS are "regular" files though, so the base class
has a non-pure virtual method.
Lastly, the DevPtsFS simply hardcodes '.' and '..' as directory file
type, and everything else is hardcoded to send the character device file
type, as this filesystem is only exposing character pts device files.
This commit adds minimal support for compiler-instrumentation based
memory access sanitization.
Currently we only support detection of kmalloc redzone accesses, and
kmalloc use-after-free accesses.
Support for inline checks (for improved performance), and for stack
use-after-return and use-after-return detection is left for future PRs.
In a bunch of cases, this actually ends up simplifying the code as
to_number will handle something such as:
```
Optional<I> opt;
if constexpr (IsSigned<I>)
opt = view.to_int<I>();
else
opt = view.to_uint<I>();
```
For us.
The main goal here however is to have a single generic number conversion
API between all of the String classes.
RAMFS was passing 0, which lead to the userspace seeing all entries as
DT_UNKNOWN when iterating over the directory contents.
To repro prior to this commit, simply check `echo /tmp/*/`.
When writing to /sys/kernel/request_panic it will do a kernel panic.
Trying to truncate the node will result in kernel panic with a slightly
different message.
When the FileSystem does a sync, it gathers up all the inodes with
dirty metadata into a vector. The inode mutex is not held while
checking the inode dirty bit, which can lead to a kernel panic
due to concurrent inode modifications.
Fixes: #21796
