mirror of
https://github.com/RGBCube/serenity
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64 lines
2.1 KiB
C++
64 lines
2.1 KiB
C++
/*
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* Copyright (c) 2022, Leon Albrecht <leon.a@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/Checked.h>
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#include <Kernel/FileSystem/Inode.h>
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#include <Kernel/FileSystem/InodeFile.h>
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#include <Kernel/FileSystem/OpenFileDescription.h>
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#include <Kernel/Tasks/Process.h>
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namespace Kernel {
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// https://pubs.opengroup.org/onlinepubs/9699919799/functions/posix_fallocate.html
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ErrorOr<FlatPtr> Process::sys$posix_fallocate(int fd, Userspace<off_t const*> userspace_offset, Userspace<off_t const*> userspace_length)
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{
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VERIFY_NO_PROCESS_BIG_LOCK(this);
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TRY(require_promise(Pledge::stdio));
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// [EINVAL] The len argument is less than zero, or the offset argument is less than zero, or the underlying file system does not support this operation.
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auto offset = TRY(copy_typed_from_user(userspace_offset));
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if (offset < 0)
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return EINVAL;
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auto length = TRY(copy_typed_from_user(userspace_length));
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if (length <= 0)
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return EINVAL;
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Checked<size_t> checked_size { length };
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checked_size += offset;
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// FIXME: Return EFBIG if offset+length > FileSizeMax
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if (checked_size.has_overflow())
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return EFBIG;
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auto description = TRY(open_file_description(fd));
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// [EBADF] The fd argument references a file that was opened without write permission.
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if (!description->is_writable())
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return EBADF;
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// [ESPIPE] The fd argument is associated with a pipe or FIFO.
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if (description->is_fifo())
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return ESPIPE;
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// [ENODEV] The fd argument does not refer to a regular file.
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if (!description->file().is_regular_file())
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return ENODEV;
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VERIFY(description->file().is_inode());
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auto& file = static_cast<InodeFile&>(description->file());
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if (file.inode().size() >= checked_size.value())
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return 0;
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// Note: truncate essentially calls resize in the inodes implementation
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// while resize is not a standard member of an inode, so we just call
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// truncate instead
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TRY(file.inode().truncate(checked_size.value()));
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// FIXME: EINTR: A signal was caught during execution.
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return 0;
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}
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}
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