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https://github.com/SerenityOS/serenity
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3692af528e
There's no point in constructing an object just for the sake of keeping a state that can be touched by anything in the kernel code. Let's reduce everything to be in a C++ namespace called with the previous name "VirtualFileSystem" and keep a smaller textual-footprint struct called "VirtualFileSystemDetails". This change also cleans up old "friend class" statements that were no longer needed, and move methods from the VirtualFileSystem code to more appropriate places as well. Please note that the method of locking all filesystems during shutdown is removed, as in that place there's no meaning to actually locking all filesystems because of running in kernel mode entirely.
38 lines
1.4 KiB
C++
38 lines
1.4 KiB
C++
/*
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* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <AK/StringView.h>
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#include <Kernel/FileSystem/VirtualFileSystem.h>
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#include <Kernel/Tasks/Process.h>
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namespace Kernel {
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ErrorOr<FlatPtr> Process::sys$readlink(Userspace<Syscall::SC_readlink_params const*> user_params)
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{
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VERIFY_NO_PROCESS_BIG_LOCK(this);
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TRY(require_promise(Pledge::rpath));
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auto params = TRY(copy_typed_from_user(user_params));
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auto path = TRY(get_syscall_path_argument(params.path));
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auto description = TRY(VirtualFileSystem::open(vfs_root_context(), credentials(), path->view(), O_RDONLY | O_NOFOLLOW_NOERROR, 0, TRY(custody_for_dirfd(params.dirfd))));
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if (!description->metadata().is_symlink())
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return EINVAL;
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// Make sure that our assumptions about the path length hold up.
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// Note that this doesn't mean that the reported size can be trusted, some inodes just report zero.
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VERIFY(description->inode()->size() <= MAXPATHLEN);
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Array<u8, MAXPATHLEN> link_target;
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auto read_bytes = TRY(description->inode()->read_until_filled_or_end(0, link_target.size(), UserOrKernelBuffer::for_kernel_buffer(link_target.data()), description));
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auto size_to_copy = min(read_bytes, params.buffer.size);
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TRY(copy_to_user(params.buffer.data, link_target.data(), size_to_copy));
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// Note: we return the whole size here, not the copied size.
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return read_bytes;
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}
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}
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