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/*
* Copyright (c) 2022, Leon Albrecht <leon.a@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Checked.h>
#include <Kernel/FileSystem/Inode.h>
#include <Kernel/FileSystem/InodeFile.h>
#include <Kernel/FileSystem/OpenFileDescription.h>
#include <Kernel/Tasks/Process.h>
namespace Kernel {
// https://pubs.opengroup.org/onlinepubs/9699919799/functions/posix_fallocate.html
ErrorOr<FlatPtr> Process::sys$posix_fallocate(int fd, Userspace<off_t const*> userspace_offset, Userspace<off_t const*> userspace_length)
{
VERIFY_NO_PROCESS_BIG_LOCK(this);
TRY(require_promise(Pledge::stdio));
// [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.
auto offset = TRY(copy_typed_from_user(userspace_offset));
if (offset < 0)
return EINVAL;
auto length = TRY(copy_typed_from_user(userspace_length));
if (length <= 0)
return EINVAL;
Checked<size_t> checked_size { length };
checked_size += offset;
// FIXME: Return EFBIG if offset+length > FileSizeMax
if (checked_size.has_overflow())
return EFBIG;
auto description = TRY(open_file_description(fd));
// [EBADF] The fd argument references a file that was opened without write permission.
if (!description->is_writable())
return EBADF;
// [ESPIPE] The fd argument is associated with a pipe or FIFO.
if (description->is_fifo())
return ESPIPE;
// [ENODEV] The fd argument does not refer to a regular file.
if (!description->file().is_regular_file())
return ENODEV;
VERIFY(description->file().is_inode());
auto& file = static_cast<InodeFile&>(description->file());
if (file.inode().size() >= checked_size.value())
return 0;
// Note: truncate essentially calls resize in the inodes implementation
// while resize is not a standard member of an inode, so we just call
// truncate instead
TRY(file.inode().truncate(checked_size.value()));
// FIXME: EINTR: A signal was caught during execution.
return 0;
}
}
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