ladybird/Kernel/Syscalls/fallocate.cpp
Daniel Bertalan 286984750e Kernel+LibC: Pass 64-bit integers in syscalls by value
Now that support for 32-bit x86 has been removed, we don't have to worry
about the top half of `off_t`/`u64` values being chopped off when we try
to pass them in registers. Therefore, we no longer need the workaround
of pointers to stack-allocated values to syscalls.

Note that this changes the system call ABI, so statically linked
programs will have to be re-linked.
2023-08-12 01:14:26 +02:00

63 lines
1.9 KiB
C++

/*
* 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, off_t offset, off_t 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.
if (offset < 0)
return EINVAL;
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;
}
}