serenity/Kernel/Syscalls/hostname.cpp

/*
 * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#include <Kernel/Process.h>

namespace Kernel {

ErrorOr<FlatPtr> Process::sys$gethostname(Userspace<char*> buffer, size_t size)
{
    VERIFY_NO_PROCESS_BIG_LOCK(this);
    TRY(require_promise(Pledge::stdio));
    if (size > NumericLimits<ssize_t>::max())
        return EINVAL;
    return hostname().with_shared([&](auto const& name) -> ErrorOr<FlatPtr> {
        if (size < (name->length() + 1))
            return ENAMETOOLONG;
        TRY(copy_to_user(buffer, name->characters(), name->length() + 1));
        return 0;
    });
}

ErrorOr<FlatPtr> Process::sys$sethostname(Userspace<char const*> buffer, size_t length)
{
    VERIFY_NO_PROCESS_BIG_LOCK(this);
    TRY(require_no_promises());

    auto credentials = this->credentials();
    if (!credentials->is_superuser())
        return EPERM;
    if (length > 64)
        return ENAMETOOLONG;
    auto new_name = TRY(try_copy_kstring_from_user(buffer, length));
    hostname().with_exclusive([&](auto& name) {
        name = move(new_name);
    });
    return 0;
}

}