This adds KLexicalPath::try_join(). As this cannot be done without
allocation, it uses KString and can fail. This patch also uses it at one
place. All the other cases of String::formatted("{}/{}", ...) currently
rely on the return value being a String, which means they cannot easily
be converted to use the new API.
This replaces all uses of LexicalPath in the Kernel with the functions
from KLexicalPath. This also allows the Kernel to stop including
AK::LexicalPath.
This change enforces that paths passed to
VFS::validate_path_against_process_veil are absolute and do not contain
any '..' or '.' parts. We should VERIFY here instead of returning EINVAL
since the code that calls this should resolve non-canonical paths before
calling this function.
Previously, Custody::absolute_path() was called for every call to
validate_path_against_process_veil(). For processes that don't have a
veil, the path is not used by the function. This means that it is
unnecessarily generated. This introduces an overload to
validate_path_against_process_veil(), which takes a Custody const& and
only generates the absolute path if it there is actually a veil and it
is thus needed.
This patch results in a speed up of Assistant's file system cache
building by around 16 percent.
These small changes fix the remaining warnings that come up during
kernel compilation with Clang. These specific fixes were for benign
things: unused lambda captures and braces around scalar initializers.
The `#pragma GCC diagnostic` part is needed because the class has
virtual methods with the same name but different arguments, and Clang
tries to warn us that we are not actually overriding anything with
these.
Weirdly enough, GCC does not seem to care.
Now we use WeakPtrs to break Ref-counting cycle. Also, we call the
prepare_for_deletion method to ensure deleted objects are ready for
deletion. This is necessary to ensure we don't keep dead processes,
which would become zombies.
In addition to that, add some debug prints to aid debug in the future.
This changes the m_parts, m_dirname, m_basename, m_title and m_extension
member variables to StringViews onto the m_string String. It also
removes the m_is_absolute member in favour of computing if a path is
absolute in the is_absolute() getter. Due to this, the canonicalize()
method has been completely rewritten.
The parts() getter still returns a Vector<String>, although it is no
longer a const reference as m_parts is no longer a Vector<String>.
Rather, it is constructed from the StringViews in m_parts upon request.
The parts_view() getter has been added, which returns Vector<StringView>
const&. Most previous users of parts() have been changed to use
parts_view(), except where Strings are required.
Due to this change, it's is now no longer allow to create temporary
LexicalPath objects to call the dirname, basename, title, or extension
getters on them because the returned StringViews will point to possible
freed memory.
The LexicalPath instance methods dirname(), basename(), title() and
extension() will be changed to return StringView const& in a further
commit. Due to this, users creating temporary LexicalPath objects just
to call one of those getters will recieve a StringView const& pointing
to a possible freed buffer.
To avoid this, static methods for those APIs have been added, which will
return a String by value to avoid those problems. All cases where
temporary LexicalPath objects have been used as described above haven
been changed to use the static APIs.
It didn't make any sense to hardcode the modified time of all created
inodes with "mepoch", so we should query the procfs "backend" to get
the modified time value.
Since ProcFS is dynamically changed all the time, the modified time
equals to the querying time.
This could be changed if desired, by making the modified_time()
method virtual and overriding it in different procfs-backed objects :)
The new ProcFS design consists of two main parts:
1. The representative ProcFS class, which is derived from the FS class.
The ProcFS and its inodes are much more lean - merely 3 classes to
represent the common type of inodes - regular files, symbolic links and
directories. They're backed by a ProcFSExposedComponent object, which
is responsible for the functional operation behind the scenes.
2. The backend of the ProcFS - the ProcFSComponentsRegistrar class
and all derived classes from the ProcFSExposedComponent class. These
together form the entire backend and handle all the functions you can
expect from the ProcFS.
The ProcFSExposedComponent derived classes split to 3 types in the
manner of lifetime in the kernel:
1. Persistent objects - this category includes all basic objects, like
the root folder, /proc/bus folder, main blob files in the root folders,
etc. These objects are persistent and cannot die ever.
2. Semi-persistent objects - this category includes all PID folders,
and subdirectories to the PID folders. It also includes exposed objects
like the unveil JSON'ed blob. These object are persistent as long as the
the responsible process they represent is still alive.
3. Dynamic objects - this category includes files in the subdirectories
of a PID folder, like /proc/PID/fd/* or /proc/PID/stacks/*. Essentially,
these objects are always created dynamically and when no longer in need
after being used, they're deallocated.
Nevertheless, the new allocated backend objects and inodes try to use
the same InodeIndex if possible - this might change only when a thread
dies and a new thread is born with a new thread stack, or when a file
descriptor is closed and a new one within the same file descriptor
number is opened. This is needed to actually be able to do something
useful with these objects.
The new design assures that many ProcFS instances can be used at once,
with one backend for usage for all instances.
The intention is to add dynamic mechanism for notifying the userspace
about hotplug events. Currently, the DMI (SMBIOS) blobs and ACPI tables
are exposed in the new filesystem.
This commit converts naked `new`s to `AK::try_make` and `AK::try_create`
wherever possible. If the called constructor is private, this can not be
done, so we instead now use the standard-defined and compiler-agnostic
`new (nothrow)`.
This fixes#8133.
Ext2FSInode::remove_child() searches the lookup cache, so if it's not
initialized, removing the child fails. If the child was a directory,
this led to it being corrupted and having 0 children.
I also added populate_lookup_cache to add_child. I hadn't seen any
bugs there, but if the cache wasn't populated before, adding that
one entry would make it think it was populated, so that would cause
bugs later.
inode identifiers in ProcFS are encoded in a way that the parent ID is
shifted 12 bits to the left and the PID is shifted by 16 bits. This
means that the rightmost 12 bits are reserved for the file type or the
fd.
Since the to_fd and to_proc_file_type decoders only decoded the
rightmost 8 bits, decoded values would wrap around beyond values of 255,
resulting in a different value compared to what was originally encoded.
