Add spring remoting server

Added a spring remoting server.

docker/spring-remoting/Dockerfile

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+###########################################
+###            Build Stage 1            ###
+###########################################
+FROM maven:3.8.6-openjdk-8-slim AS maven-builder
+COPY ./resources/server /usr/src/app
+WORKDIR /usr/src/app
+RUN mvn clean package
+
+###########################################
+###            Build Stage 2            ###
+###########################################
+FROM alpine:latest AS jdk-builder
+RUN set -ex \
+    && apk add --no-cache openjdk11 \
+    && /usr/lib/jvm/java-11-openjdk/bin/jlink --add-modules java.rmi,java.management.rmi,jdk.unsupported --verbose --strip-debug --compress 2 \
+       --no-header-files --no-man-pages --output /jdk
+
+###########################################
+###          Container Stage            ###
+###########################################
+FROM alpine:latest
+
+COPY ./resources/scripts/start.sh /opt/start.sh
+COPY --from=maven-builder /usr/src/app/target/rmg-spring-remoting-server-*-jar-with-dependencies.jar /opt/remoting-server.jar
+COPY --from=jdk-builder /jdk /usr/lib/jvm/java-11-openjdk
+
+RUN set -ex \
+    && ln -s /usr/lib/jvm/java-11-openjdk/bin/java /usr/bin/java \
+    && chmod +x /opt/start.sh
+
+ENV _JAVA_OPTIONS -Djava.rmi.server.hostname=iinsecure.example 
+
+EXPOSE 1099/tcp
+
+CMD ["/opt/start.sh"]

docker/spring-remoting/resources/scripts/start.sh

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+#!/bin/ash
+
+IP=$(ip a | grep inet | grep -v 127.0.0.1 | grep -o "\([0-9]\{1,3\}\.\?\)\{4\}" | head -n 1)
+echo "[+] IP address of the container: ${IP}" 
+
+echo "[+] Adding gateway address to /etc/hosts file..."
+GATEWAY=$(ip r | grep "default via" | cut -d" " -f 3)
+echo "$GATEWAY prevent.reverse.dns" >> /etc/hosts
+
+echo "[+] Adding RMI hostname to /etc/hosts file..."
+echo "127.0.0.1 iinsecure.example" >> /etc/hosts
+
+echo "[+] Starting rmi server..."
+exec /usr/bin/java -jar /opt/remoting-server.jar

docker/spring-remoting/resources/server/pom.xml

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+<project xmlns="https://maven.apache.org/POM/4.0.0" xmlns:xsi="https://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>de.qtc.rmg</groupId>
+    <artifactId>spring-remoting</artifactId>
+    <version>1.0.0</version>
+
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <maven.compiler.source>1.8</maven.compiler.source>
+        <maven.compiler.target>1.8</maven.compiler.target>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-web</artifactId>
+            <exclusions>
+                <exclusion>
+                    <groupId>org.springframework.boot</groupId>
+                    <artifactId>spring-boot-starter-tomcat</artifactId>
+                </exclusion>
+            </exclusions>
+            <version>2.7.16</version>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <artifactId>maven-assembly-plugin</artifactId>
+                <executions>
+                    <execution>
+                    <phase>package</phase>
+                    <goals>
+                        <goal>single</goal>
+                    </goals>
+                    </execution>
+                </executions>
+                <configuration>
+                    <finalName>rmg-spring-remoting-server-${project.version}</finalName>
+                    <archive>
+                        <manifest>
+                            <mainClass>de.qtc.rmg.springremoting.Starter</mainClass>
+                            <addDefaultImplementationEntries>true</addDefaultImplementationEntries>
+                        </manifest>
+                    </archive>
+                    <descriptorRefs>
+                        <descriptorRef>jar-with-dependencies</descriptorRef>
+                    </descriptorRefs>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+</project>

docker/spring-remoting/resources/server/src/main/java/de/qtc/rmg/springremoting/ServerOperations.java

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+package de.qtc.rmg.springremoting;
+
+public interface ServerOperations
+{
+    String notRelevant();
+    String execute(String cmd);
+    String system(String cmd, String[] args);
+    String upload(int size, int id, byte[] content);
+    int math(int num1, int num2);
+}

docker/spring-remoting/resources/server/src/main/java/de/qtc/rmg/springremoting/SpringRemotingService.java

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+package de.qtc.rmg.springremoting;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.context.annotation.Bean;
+import org.springframework.remoting.rmi.RmiServiceExporter;
+
+@SuppressWarnings("deprecation")
+public class SpringRemotingService implements ServerOperations
+{
+	Logger logger = LoggerFactory.getLogger(SpringRemotingService.class);
+
+	SpringRemotingService springRemotingService()
+	{
+		return new SpringRemotingService();
+	}
+
+	@Bean
+	RmiServiceExporter exporter(SpringRemotingService impl)
+	{
+		Class<ServerOperations> serverInterface = ServerOperations.class;
+		RmiServiceExporter exporter = new RmiServiceExporter();
+
+		exporter.setServiceInterface(serverInterface);
+		exporter.setService(impl);
+		exporter.setServiceName("spring-remoting");
+		exporter.setRegistryPort(1099);
+
+		return exporter;
+	}
+
+	public String notRelevant()
+	{
+		logger.info("Method", "notRelevant", "was called.");
+		return "Hello World :D";
+	}
+
+    public String execute(String command)
+    {
+    	logger.info("Processing call for", "String execute(String command)");
+        String result = "";
+
+        try
+        {
+            Process p = java.lang.Runtime.getRuntime().exec(command);
+            p.waitFor();
+            result = readFromProcess(p);
+        }
+
+        catch (IOException | InterruptedException e)
+        {
+            result = "Exception: " + e.getMessage();
+        }
+
+        return result;
+    }
+
+    public String system(String command, String[] args)
+    {
+    	logger.info("Processing call for", "String system(String command, String[] args)");
+        String result = "";
+
+        String[] commandArray = new String[args.length + 1];
+        commandArray[0] = command;
+        System.arraycopy(args, 0, commandArray, 1, args.length);
+
+        try
+        {
+            Process p = java.lang.Runtime.getRuntime().exec(commandArray);
+            p.waitFor();
+            result = readFromProcess(p);
+        }
+
+        catch (IOException | InterruptedException e)
+        {
+            result = "Exception: " + e.getMessage();
+        }
+
+        return result;
+    }
+
+    public String upload(int size, int id, byte[] content)
+    {
+    	logger.info("Processing call for", "String upload(int size, int id, byte[] content)");
+        return "Upload of size " + size + " was saved as user_uploads_" + id + ".";
+    }
+
+    public int math(int num1, int num2)
+    {
+    	logger.info("Processing call for", "int math(int num1, int num2)");
+        return num1 / num2;
+    }
+
+    private static String readFromProcess(Process p) throws IOException
+    {
+        StringBuilder result = new StringBuilder();
+
+        BufferedReader reader = new BufferedReader(new InputStreamReader(p.getInputStream()));
+        String line = reader.readLine();
+
+        while (line != null)
+        {
+            result.append(line);
+            line = reader.readLine();
+        }
+
+        reader = new BufferedReader(new InputStreamReader(p.getErrorStream()));
+        line = reader.readLine();
+
+        while (line != null)
+        {
+            result.append(line);
+            line = reader.readLine();
+        }
+
+        return result.toString();
+    }
+}

docker/spring-remoting/resources/server/src/main/java/de/qtc/rmg/springremoting/Starter.java

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+package de.qtc.rmg.springremoting;
+
+import org.springframework.boot.SpringApplication;
+
+public class Starter
+{
+    public static void main(String[] args)
+    {
+        SpringApplication.run(SpringRemotingService.class, args);
+    }
+}