ladybird/Kernel/Syscalls/chdir.cpp
Ben Wiederhake ea5825f2c9 Kernel+LibC: Make sys$getcwd truncate the result silently
This gives us the superpower of knowing the ideal buffer length if it fails.
See also https://github.com/SerenityOS/serenity/discussions/4357
2021-01-16 22:40:53 +01:00

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2.7 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <Kernel/FileSystem/Custody.h>
#include <Kernel/FileSystem/FileDescription.h>
#include <Kernel/FileSystem/VirtualFileSystem.h>
#include <Kernel/Process.h>
namespace Kernel {
int Process::sys$chdir(Userspace<const char*> user_path, size_t path_length)
{
REQUIRE_PROMISE(rpath);
auto path = get_syscall_path_argument(user_path, path_length);
if (path.is_error())
return path.error();
auto directory_or_error = VFS::the().open_directory(path.value(), current_directory());
if (directory_or_error.is_error())
return directory_or_error.error();
m_cwd = *directory_or_error.value();
return 0;
}
int Process::sys$fchdir(int fd)
{
REQUIRE_PROMISE(stdio);
auto description = file_description(fd);
if (!description)
return -EBADF;
if (!description->is_directory())
return -ENOTDIR;
if (!description->metadata().may_execute(*this))
return -EACCES;
m_cwd = description->custody();
return 0;
}
int Process::sys$getcwd(Userspace<char*> buffer, size_t size)
{
REQUIRE_PROMISE(rpath);
auto path = current_directory().absolute_path();
size_t ideal_size = path.length() + 1;
auto size_to_copy = min(ideal_size, size);
if (!copy_to_user(buffer, path.characters(), size_to_copy))
return -EFAULT;
// Note: we return the whole size here, not the copied size.
return ideal_size;
}
}