ladybird/Kernel/Syscalls/lseek.cpp
Liav A 7c87891c06 Kernel: Don't copy a Vector<FileDescriptionAndFlags>
Instead of copying a Vector everytime we need to enumerate a Process'
file descriptions, we can just temporarily lock so it won't change.
2021-06-29 20:53:59 +02:00

30 lines
763 B
C++

/*
* 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$lseek(int fd, Userspace<off_t*> userspace_offset, int whence)
{
REQUIRE_PROMISE(stdio);
auto description = fds().file_description(fd);
if (!description)
return EBADF;
off_t offset;
if (!copy_from_user(&offset, userspace_offset))
return EFAULT;
auto seek_result = description->seek(offset, whence);
if (seek_result.is_error())
return seek_result.error();
if (!copy_to_user(userspace_offset, &seek_result.value()))
return EFAULT;
return KSuccess;
}
}