Solved the problem of threaddeath infinite loop

Author: Alathreon

JShellAPI/src/main/java/org/togetherjava/jshellapi/Config.java

@@ -7,6 +7,7 @@ public record Config(
         long regularSessionTimeoutSeconds,
         long oneTimeSessionTimeoutSeconds,
         long evalTimeoutSeconds,
+        long evalTimeoutValidationLeeway,
         int sysOutCharLimit,
         long maxAliveSessions,
         int dockerMaxRamMegaBytes,
@@ -18,6 +19,7 @@ public record Config(
         if(regularSessionTimeoutSeconds <= 0) throw new RuntimeException("Invalid value " + regularSessionTimeoutSeconds);
         if(oneTimeSessionTimeoutSeconds <= 0) throw new RuntimeException("Invalid value " + oneTimeSessionTimeoutSeconds);
         if(evalTimeoutSeconds <= 0) throw new RuntimeException("Invalid value " + evalTimeoutSeconds);
+        if(evalTimeoutValidationLeeway <= 0) throw new RuntimeException("Invalid value " + evalTimeoutSeconds);
         if(sysOutCharLimit <= 0) throw new RuntimeException("Invalid value " + sysOutCharLimit);
         if(maxAliveSessions <= 0) throw new RuntimeException("Invalid value " + maxAliveSessions);
         if(dockerMaxRamMegaBytes <= 0) throw new RuntimeException("Invalid value " + dockerMaxRamMegaBytes);

JShellAPI/src/main/java/org/togetherjava/jshellapi/service/JShellService.java

@@ -22,15 +22,19 @@ public class JShellService implements Closeable {
     private Instant lastTimeoutUpdate;
     private final long timeout;
     private final boolean renewable;
+    private final long evalTimeoutValidationLeeway;
+    private final long evalTimeout;
     private boolean doingOperation;
     private final DockerService dockerService;
 
-    public JShellService(DockerService dockerService, JShellSessionService sessionService, String id, long timeout, boolean renewable, long evalTimeout, int sysOutCharLimit, int maxMemory, double cpus, String startupScript) throws DockerException {
+    public JShellService(DockerService dockerService, JShellSessionService sessionService, String id, long timeout, boolean renewable, long evalTimeout, long evalTimeoutValidationLeeway, int sysOutCharLimit, int maxMemory, double cpus, String startupScript) throws DockerException {
         this.dockerService = dockerService;
         this.sessionService = sessionService;
         this.id = id;
         this.timeout = timeout;
         this.renewable = renewable;
+        this.evalTimeout = evalTimeout;
+        this.evalTimeoutValidationLeeway = evalTimeoutValidationLeeway;
         this.lastTimeoutUpdate = Instant.now();
         try {
             Path errorLogs = Path.of("logs", "container", containerName() + ".log");
@@ -70,6 +74,7 @@ public Optional<JShellResult> eval(String code) throws DockerException {
             return Optional.empty();
         }
         updateLastTimeout();
+        sessionService.scheduleEvalTimeoutValidation(id, evalTimeout + evalTimeoutValidationLeeway);
         if(!code.endsWith("\n")) code += '\n';
         try {
             writer.write("eval");
@@ -161,6 +166,10 @@ public String containerName() {
         return "session_" + id;
     }
 
+    public boolean isInvalidEvalTimeout() {
+        return doingOperation && lastTimeoutUpdate.plusSeconds(evalTimeout + evalTimeoutValidationLeeway).isBefore(Instant.now());
+    }
+
     public boolean shouldDie() {
         return lastTimeoutUpdate.plusSeconds(timeout).isBefore(Instant.now());
     }

JShellAPI/src/main/java/org/togetherjava/jshellapi/service/JShellSessionService.java

@@ -52,15 +52,15 @@ public boolean hasSession(String id) {
 
     public JShellService session(String id, @Nullable StartupScriptId startupScriptId) throws DockerException {
         if(!hasSession(id)) {
-            return createSession(id, config.regularSessionTimeoutSeconds(), true, config.evalTimeoutSeconds(), config.sysOutCharLimit(), startupScriptId);
+            return createSession(id, config.regularSessionTimeoutSeconds(), true, config.evalTimeoutSeconds(), config.evalTimeoutValidationLeeway(), config.sysOutCharLimit(), startupScriptId);
         }
         return jshellSessions.get(id);
     }
     public JShellService session(@Nullable StartupScriptId startupScriptId) throws DockerException {
-        return createSession(UUID.randomUUID().toString(), config.regularSessionTimeoutSeconds(), false, config.evalTimeoutSeconds(), config.sysOutCharLimit(), startupScriptId);
+        return createSession(UUID.randomUUID().toString(), config.regularSessionTimeoutSeconds(), false, config.evalTimeoutSeconds(), config.evalTimeoutValidationLeeway(), config.sysOutCharLimit(), startupScriptId);
     }
     public JShellService oneTimeSession(@Nullable StartupScriptId startupScriptId) throws DockerException {
-        return createSession(UUID.randomUUID().toString(), config.oneTimeSessionTimeoutSeconds(), false, config.evalTimeoutSeconds(), config.sysOutCharLimit(), startupScriptId);
+        return createSession(UUID.randomUUID().toString(), config.oneTimeSessionTimeoutSeconds(), false, config.evalTimeoutSeconds(), config.evalTimeoutValidationLeeway(), config.sysOutCharLimit(), startupScriptId);
     }
 
     public void deleteSession(String id) throws DockerException {
@@ -69,7 +69,7 @@ public void deleteSession(String id) throws DockerException {
         scheduler.schedule(service::close, 500, TimeUnit.MILLISECONDS);
     }
 
-    private synchronized JShellService createSession(String id, long sessionTimeout, boolean renewable, long evalTimeout, int sysOutCharLimit, @Nullable StartupScriptId startupScriptId) throws DockerException {
+    private synchronized JShellService createSession(String id, long sessionTimeout, boolean renewable, long evalTimeout, long evalTimeoutValidationLeeway, int sysOutCharLimit, @Nullable StartupScriptId startupScriptId) throws DockerException {
         if(hasSession(id)) {    //Just in case race condition happens just before createSession
             return jshellSessions.get(id);
         }
@@ -83,6 +83,7 @@ private synchronized JShellService createSession(String id, long sessionTimeout,
                 sessionTimeout,
                 renewable,
                 evalTimeout,
+                evalTimeoutValidationLeeway,
                 sysOutCharLimit,
                 config.dockerMaxRamMegaBytes(),
                 config.dockerCPUsUsage(),
@@ -91,6 +92,23 @@ private synchronized JShellService createSession(String id, long sessionTimeout,
         return service;
     }
 
+    /**
+     * Schedule the validation of the session timeout.
+     * In case the code runs for too long, checks if the wrapper correctly followed the eval timeout and canceled it,
+     * if it didn't, forcefully close the session.
+     * @param id the id of the session
+     * @param timeSeconds the time to schedule
+     */
+    public void scheduleEvalTimeoutValidation(String id, long timeSeconds) {
+        scheduler.schedule(() -> {
+            JShellService service = jshellSessions.get(id);
+            if(service == null) return;
+            if(service.isInvalidEvalTimeout()) {
+                service.close();
+            }
+        }, timeSeconds, TimeUnit.SECONDS);
+    }
+
     @Autowired
     public void setConfig(Config config) {
         this.config = config;

JShellAPI/src/main/resources/application.properties

@@ -3,6 +3,7 @@
 jshellapi.regularSessionTimeoutSeconds=1800
 jshellapi.oneTimeSessionTimeoutSeconds=30
 jshellapi.evalTimeoutSeconds=15
+jshellapi.evalTimeoutValidationLeeway=10
 jshellapi.sysOutCharLimit=1024
 jshellapi.maxAliveSessions=10