serenity/Kernel/Syscalls/ftruncate.cpp
Andreas Kling 39d9337db5 Kernel: Make sys${ftruncate,pread} take off_t as const pointer
These syscalls don't write back to the off_t value (unlike sys$lseek)
so let's take Userspace<off_t const*> instead of Userspace<off_t*>.
2021-12-18 11:30:10 +01:00

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/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <Kernel/FileSystem/OpenFileDescription.h>
#include <Kernel/Process.h>
namespace Kernel {
ErrorOr<FlatPtr> Process::sys$ftruncate(int fd, Userspace<off_t const*> userspace_length)
{
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
REQUIRE_PROMISE(stdio);
auto length = TRY(copy_typed_from_user(userspace_length));
if (length < 0)
return EINVAL;
auto description = TRY(fds().open_file_description(fd));
if (!description->is_writable())
return EBADF;
TRY(description->truncate(static_cast<u64>(length)));
return 0;
}
}