serenity/Kernel/Syscalls/ftruncate.cpp
Gunnar Beutner 2a78bf8596 Kernel: Fix the return type for syscalls
The Process::Handler type has KResultOr<FlatPtr> as its return type.
Using a different return type with an equally-sized template parameter
sort of works but breaks once that condition is no longer true, e.g.
for KResultOr<int> on x86_64.

Ideally the syscall handlers would also take FlatPtrs as their args
so we can get rid of the reinterpret_cast for the function pointer
but I didn't quite feel like cleaning that up as well.
2021-06-28 22:29:28 +02:00

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