ladybird/Kernel/Syscalls/chdir.cpp

/*
 * 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;
}

}