/*
 * Copyright (c) 2018, 2019, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package com.oracle.svm.driver;

import java.util.Arrays;
import java.util.List;

import org.graalvm.compiler.api.replacements.Fold;
import org.graalvm.nativeimage.Platform;
import org.graalvm.nativeimage.Platforms;
import org.graalvm.nativeimage.c.CContext;
import org.graalvm.nativeimage.c.function.CFunction;

public class NativeImageServerHelper {
    @Fold
    public static boolean isInConfiguration() {
        return Platform.includedIn(Platform.LINUX.class) || Platform.includedIn(Platform.DARWIN.class);
    }

    /*
     * Ensures started server keeps running even after native-image completes.
     */
    @Platforms({Platform.LINUX.class, Platform.DARWIN.class})
    static int daemonize(Runnable runnable) {
        int pid = Unistd.fork();
        switch (pid) {
            case 0:
                break;
            default:
                return pid;
        }

        /* The server should not get signals from the native-image during the first run. */
        Unistd.setsid();

        runnable.run();
        System.exit(0);
        return -1;
    }
}

@Platforms({Platform.LINUX.class, Platform.DARWIN.class})
class UnistdDirectives implements CContext.Directives {
    @Override
    public boolean isInConfiguration() {
        return NativeImageServerHelper.isInConfiguration();
    }

    @Override
    public List<String> getHeaderFiles() {
        return Arrays.asList(new String[]{"<unistd.h>"});
    }

    @Override
    public List<String> getMacroDefinitions() {
        return Arrays.asList("_GNU_SOURCE", "_LARGEFILE64_SOURCE");
    }
}

@Platforms({Platform.LINUX.class, Platform.DARWIN.class})
@CContext(UnistdDirectives.class)
class Unistd {
    
Create a new session with the calling process as its leader. The process group IDs of the
session and the calling process are set to the process ID of the calling process, which is
returned.
/**
     * Create a new session with the calling process as its leader. The process group IDs of the
     * session and the calling process are set to the process ID of the calling process, which is
     * returned.
     */
    @CFunction
    public static native int setsid();

    
Return the session ID of the given process. /** Return the session ID of the given process. */
    @CFunction
    public static native int getsid(int pid);

    
Return identifier for the current host. /** Return identifier for the current host. */
    @CFunction
    public static native long gethostid();

    
Clone the calling process, creating an exact copy. Return -1 for errors, 0 to the new
process, and the process ID of the new process to the old process.
/**
     * Clone the calling process, creating an exact copy. Return -1 for errors, 0 to the new
     * process, and the process ID of the new process to the old process.
     */
    @CFunction
    public static native int fork();
}