HDFS-14348: Fix JNI exception handling issues in libhdfs

This closes #600

Signed-off-by: Todd Lipcon <todd@apache.org>

hadoop-hdfs-project/hadoop-hdfs-native-client/src/main/native/libhdfs/hdfs.c

@@ -2491,6 +2491,8 @@ int hadoopRzOptionsSetByteBufferPool(
     JNIEnv *env;
     jthrowable jthr;
     jobject byteBufferPool = NULL;
+    jobject globalByteBufferPool = NULL;
+    int ret;
 
     env = getJNIEnv();
     if (!env) {
@@ -2507,15 +2509,37 @@ int hadoopRzOptionsSetByteBufferPool(
       if (jthr) {
           printExceptionAndFree(env, jthr, PRINT_EXC_ALL,
               "hadoopRzOptionsSetByteBufferPool(className=%s): ", className);
-          errno = EINVAL;
+          ret = EINVAL;
-          return -1;
+          goto done;
       }
+      // Only set opts->byteBufferPool if creating a global reference is
+      // successful
+      globalByteBufferPool = (*env)->NewGlobalRef(env, byteBufferPool);
+      if (!globalByteBufferPool) {
+          printPendingExceptionAndFree(env, PRINT_EXC_ALL,
+                  "hadoopRzOptionsSetByteBufferPool(className=%s): ",
+                  className);
+          ret = EINVAL;
+          goto done;
       }
+      // Delete any previous ByteBufferPool we had before setting a new one.
       if (opts->byteBufferPool) {
-        // Delete any previous ByteBufferPool we had.
           (*env)->DeleteGlobalRef(env, opts->byteBufferPool);
       }
-    opts->byteBufferPool = (*env)->NewGlobalRef(env, byteBufferPool);
+      opts->byteBufferPool = globalByteBufferPool;
+    } else if (opts->byteBufferPool) {
+        // If the specified className is NULL, delete any previous
+        // ByteBufferPool we had.
+        (*env)->DeleteGlobalRef(env, opts->byteBufferPool);
+        opts->byteBufferPool = NULL;
+    }
+    ret = 0;
+done:
+    destroyLocalReference(env, byteBufferPool);
+    if (ret) {
+        errno = ret;
+        return -1;
+    }
     return 0;
 }
 
@@ -2570,8 +2594,7 @@ static jthrowable hadoopRzOptionsGetEnumSet(JNIEnv *env,
     } else {
         jclass clazz = (*env)->FindClass(env, READ_OPTION);
         if (!clazz) {
-            jthr = newRuntimeError(env, "failed "
+            jthr = getPendingExceptionAndClear(env);
-                    "to find class for %s", READ_OPTION);
             goto done;
         }
         jthr = invokeMethod(env, &jVal, STATIC, NULL,
@@ -2697,6 +2720,7 @@ static int translateZCRException(JNIEnv *env, jthrowable exc)
     }
     if (!strcmp(className, "java.lang.UnsupportedOperationException")) {
         ret = EPROTONOSUPPORT;
+        destroyLocalReference(env, exc);
         goto done;
     }
     ret = printExceptionAndFree(env, exc, PRINT_EXC_ALL,
@@ -2896,8 +2920,9 @@ hdfsGetHosts(hdfsFS fs, const char *path, tOffset start, tOffset length)
     for (i = 0; i < jNumFileBlocks; ++i) {
         jFileBlock =
             (*env)->GetObjectArrayElement(env, jBlockLocations, i);
-        if (!jFileBlock) {
+        jthr = (*env)->ExceptionOccurred(env);
-            ret = printPendingExceptionAndFree(env, PRINT_EXC_ALL,
+        if (jthr || !jFileBlock) {
+            ret = printExceptionAndFree(env, jthr, PRINT_EXC_ALL,
                 "hdfsGetHosts(path=%s, start=%"PRId64", length=%"PRId64"):"
                 "GetObjectArrayElement(%d)", path, start, length, i);
             goto done;
@@ -2930,8 +2955,9 @@ hdfsGetHosts(hdfsFS fs, const char *path, tOffset start, tOffset length)
         //Now parse each hostname
         for (j = 0; j < jNumBlockHosts; ++j) {
             jHost = (*env)->GetObjectArrayElement(env, jFileBlockHosts, j);
-            if (!jHost) {
+            jthr = (*env)->ExceptionOccurred(env);
-                ret = printPendingExceptionAndFree(env, PRINT_EXC_ALL,
+            if (jthr || !jHost) {
+                ret = printExceptionAndFree(env, jthr, PRINT_EXC_ALL,
                     "hdfsGetHosts(path=%s, start=%"PRId64", length=%"PRId64"): "
                     "NewByteArray", path, start, length);
                 goto done;
@@ -3419,8 +3445,9 @@ hdfsFileInfo* hdfsListDirectory(hdfsFS fs, const char *path, int *numEntries)
     //Save path information in pathList
     for (i=0; i < jPathListSize; ++i) {
         tmpStat = (*env)->GetObjectArrayElement(env, jPathList, i);
-        if (!tmpStat) {
+        jthr = (*env)->ExceptionOccurred(env);
-            ret = printPendingExceptionAndFree(env, PRINT_EXC_ALL,
+        if (jthr || !tmpStat) {
+            ret = printExceptionAndFree(env, jthr, PRINT_EXC_ALL,
                 "hdfsListDirectory(%s): GetObjectArrayElement(%d out of %d)",
                 path, i, jPathListSize);
             goto done;

hadoop-hdfs-project/hadoop-hdfs-native-client/src/main/native/libhdfs/jni_helper.c

@@ -328,6 +328,11 @@ jthrowable classNameOfObject(jobject jobj, JNIEnv *env, char **name)
         goto done;
     }
     str = (*env)->CallObjectMethod(env, cls, mid);
+    jthr = (*env)->ExceptionOccurred(env);
+    if (jthr) {
+        (*env)->ExceptionClear(env);
+        goto done;
+    }
     if (str == NULL) {
         jthr = getPendingExceptionAndClear(env);
         goto done;
@@ -644,8 +649,7 @@ jthrowable fetchEnumInstance(JNIEnv *env, const char *className,
 
     clazz = (*env)->FindClass(env, className);
     if (!clazz) {
-        return newRuntimeError(env, "fetchEnum(%s, %s): failed to find class.",
+        return getPendingExceptionAndClear(env);
-                className, valueName);
     }
     if (snprintf(prettyClass, sizeof(prettyClass), "L%s;", className)
           >= sizeof(prettyClass)) {

hadoop-hdfs-project/hadoop-hdfs-native-client/src/main/native/libhdfs/os/posix/thread_local_storage.c

@@ -23,6 +23,9 @@
 #include <pthread.h>
 #include <stdio.h>
 
+#include "exception.h"
+#include "jni_helper.h"
+
 #define UNKNOWN "UNKNOWN"
 #define MAXTHRID 256
 
@@ -46,6 +49,7 @@ void hdfsThreadDestructor(void *v)
   struct ThreadLocalState *state = (struct ThreadLocalState*)v;
   JNIEnv *env = state->env;;
   jint ret;
+  jthrowable jthr;
   char thr_name[MAXTHRID];
 
   /* Detach the current thread from the JVM */
@@ -55,12 +59,20 @@ void hdfsThreadDestructor(void *v)
     if (ret != 0) {
       fprintf(stderr, "hdfsThreadDestructor: GetJavaVM failed with error %d\n",
         ret);
+      jthr = (*env)->ExceptionOccurred(env);
+      if (jthr) {
         (*env)->ExceptionDescribe(env);
+        (*env)->ExceptionClear(env);
+      }
     } else {
       ret = (*vm)->DetachCurrentThread(vm);
 
       if (ret != JNI_OK) {
+        jthr = (*env)->ExceptionOccurred(env);
+        if (jthr) {
           (*env)->ExceptionDescribe(env);
+          (*env)->ExceptionClear(env);
+        }
         get_current_thread_id(env, thr_name, MAXTHRID);
 
         fprintf(stderr, "hdfsThreadDestructor: Unable to detach thread %s "
@@ -78,44 +90,60 @@ void hdfsThreadDestructor(void *v)
 }
 
 static void get_current_thread_id(JNIEnv* env, char* id, int max) {
-  jclass cls;
+  jvalue jVal;
-  jmethodID mth;
+  jobject thr = NULL;
-  jobject thr;
+  jstring thr_name = NULL;
-  jstring thr_name;
   jlong thr_id = 0;
+  jthrowable jthr = NULL;
   const char *thr_name_str;
 
-  cls = (*env)->FindClass(env, "java/lang/Thread");
+  jthr = invokeMethod(env, &jVal, STATIC, NULL, "java/lang/Thread",
-  mth = (*env)->GetStaticMethodID(env, cls, "currentThread",
+          "currentThread", "()Ljava/lang/Thread;");
-      "()Ljava/lang/Thread;");
+  if (jthr) {
-  thr = (*env)->CallStaticObjectMethod(env, cls, mth);
+    snprintf(id, max, "%s", UNKNOWN);
+    printExceptionAndFree(env, jthr, PRINT_EXC_ALL,
+            "get_current_thread_id: Thread#currentThread failed: ");
+    goto done;
+  }
+  thr = jVal.l;
 
-  if (thr != NULL) {
+  jthr = invokeMethod(env, &jVal, INSTANCE, thr, "java/lang/Thread",
-    mth = (*env)->GetMethodID(env, cls, "getId", "()J");
+                      "getId", "()J");
-    thr_id = (*env)->CallLongMethod(env, thr, mth);
+  if (jthr) {
-    (*env)->ExceptionDescribe(env);
+    snprintf(id, max, "%s", UNKNOWN);
+    printExceptionAndFree(env, jthr, PRINT_EXC_ALL,
+            "get_current_thread_id: Thread#getId failed: ");
+    goto done;
+  }
+  thr_id = jVal.j;
 
-    mth = (*env)->GetMethodID(env, cls, "toString", "()Ljava/lang/String;");
+  jthr = invokeMethod(env, &jVal, INSTANCE, thr, "java/lang/Thread",
-    thr_name = (jstring)(*env)->CallObjectMethod(env, thr, mth);
+                      "toString", "()Ljava/lang/String;");
+  if (jthr) {
+    snprintf(id, max, "%s:%ld", UNKNOWN, thr_id);
+    printExceptionAndFree(env, jthr, PRINT_EXC_ALL,
+            "get_current_thread_id: Thread#toString failed: ");
+    goto done;
+  }
+  thr_name = jVal.l;
 
-    if (thr_name != NULL) {
   thr_name_str = (*env)->GetStringUTFChars(env, thr_name, NULL);
+  if (!thr_name_str) {
+    printPendingExceptionAndFree(env, PRINT_EXC_ALL,
+            "get_current_thread_id: GetStringUTFChars failed: ");
+    snprintf(id, max, "%s:%ld", UNKNOWN, thr_id);
+    goto done;
+  }
 
   // Treating the jlong as a long *should* be safe
   snprintf(id, max, "%s:%ld", thr_name_str, thr_id);
 
   // Release the char*
   (*env)->ReleaseStringUTFChars(env, thr_name, thr_name_str);
-    } else {
-      (*env)->ExceptionDescribe(env);
 
-      // Treating the jlong as a long *should* be safe
+done:
-      snprintf(id, max, "%s:%ld", UNKNOWN, thr_id);
+  destroyLocalReference(env, thr);
-    }
+  destroyLocalReference(env, thr_name);
-  } else {
-    (*env)->ExceptionDescribe(env);
-    snprintf(id, max, "%s", UNKNOWN);
-  }
 
   // Make sure the id is null terminated in case we overflow the max length
   id[max - 1] = '\0';