8207340: (fs) UnixNativeDispatcher close and readdir usages should be fixed

Reviewed-by: bpb

src/java.base/unix/native/libnio/fs/UnixNativeDispatcher.c

 /*
- * Copyright (c) 2008, 2017, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2008, 2018, 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
@@ -72,7 +72,7 @@
 #define fstat64 fstat
 #define lstat64 lstat
 #define dirent64 dirent
-#define readdir64_r readdir_r
+#define readdir64 readdir
 #endif
 
 #include "jni.h"
@@ -425,9 +425,17 @@ Java_sun_nio_fs_UnixNativeDispatcher_openat0(JNIEnv* env, jclass this, jint dfd,
 
 JNIEXPORT void JNICALL
 Java_sun_nio_fs_UnixNativeDispatcher_close0(JNIEnv* env, jclass this, jint fd) {
-    int err;
-    /* TDB - need to decide if EIO and other errors should cause exception */
-    RESTARTABLE(close((int)fd), err);
+    int res;
+
+#if defined(_AIX)
+    /* AIX allows close to be restarted after EINTR */
+    RESTARTABLE(close((int)fd), res);
+#else
+    res = close((int)fd);
+#endif
+    if (res == -1 && errno != EINTR) {
+        throwUnixException(env, errno);
+    }
 }
 
 JNIEXPORT jint JNICALL
@@ -720,32 +728,15 @@ Java_sun_nio_fs_UnixNativeDispatcher_closedir(JNIEnv* env, jclass this, jlong di
 
 JNIEXPORT jbyteArray JNICALL
 Java_sun_nio_fs_UnixNativeDispatcher_readdir(JNIEnv* env, jclass this, jlong value) {
-    struct dirent64* result;
-    struct {
-        struct dirent64 buf;
-        char name_extra[PATH_MAX + 1 - sizeof result->d_name];
-    } entry;
-    struct dirent64* ptr = &entry.buf;
-    int res;
     DIR* dirp = jlong_to_ptr(value);
+    struct dirent64* ptr;
 
-    /* EINTR not listed as a possible error */
-    /* TDB: reentrant version probably not required here */
-    res = readdir64_r(dirp, ptr, &result);
-
-#ifdef _AIX
-    /* On AIX, readdir_r() returns EBADF (i.e. '9') and sets 'result' to NULL for the */
-    /* directory stream end. Otherwise, 'errno' will contain the error code. */
-    if (res != 0) {
-        res = (result == NULL && res == EBADF) ? 0 : errno;
+    errno = 0;
+    ptr = readdir64(dirp);
+    if (ptr == NULL) {
+        if (errno != 0) {
+            throwUnixException(env, errno);
         }
-#endif
-
-    if (res != 0) {
-        throwUnixException(env, res);
-        return NULL;
-    } else {
-        if (result == NULL) {
         return NULL;
     } else {
         jsize len = strlen(ptr->d_name);
@@ -756,7 +747,6 @@ Java_sun_nio_fs_UnixNativeDispatcher_readdir(JNIEnv* env, jclass this, jlong val
         return bytes;
     }
 }
-}
 
 JNIEXPORT void JNICALL
 Java_sun_nio_fs_UnixNativeDispatcher_mkdir0(JNIEnv* env, jclass this,