Fix an infinite loop when attempting to read from a directory.

Raise Errno::EISDIR instead to match MRI.
jruby · Oct 29, 2017 · 963e2a1 · 963e2a1
1 parent 29137e1
commit 963e2a1
Showing 3 changed files with 23 additions and 0 deletions.
diff --git a/core/src/main/java/org/jruby/runtime/Helpers.java b/core/src/main/java/org/jruby/runtime/Helpers.java
@@ -281,6 +281,8 @@ public static Errno errnoFromException(Throwable t) {
                 case "Too many open files" : return Errno.EMFILE;
                 case "Message too large" : // Alpine Linux
                 case "Message too long" : return Errno.EMSGSIZE;
+                case "Is a directory":
+                    return Errno.EISDIR;
             }
             if (Platform.IS_WINDOWS && errorMessage.contains("connection was aborted")) return Errno.ECONNRESET;
         }

diff --git a/core/src/main/java/org/jruby/util/io/OpenFile.java b/core/src/main/java/org/jruby/util/io/OpenFile.java
@@ -1399,6 +1399,12 @@ boolean waitReadable(ThreadContext context, ChannelFD fd) {
                 return false;
             }
 
+            if (posix.errno != null && posix.errno != Errno.EAGAIN
+                    && posix.errno != Errno.EWOULDBLOCK && posix.errno != Errno.EINTR) {
+                // Encountered a permanent error. Don't read again.
+                return false;
+            }
+
             if (fd.chSelect != null) {
                 unlock();
                 try {

diff --git a/test/jruby/test_io.rb b/test/jruby/test_io.rb
@@ -384,6 +384,21 @@ def test_read_ignores_blocks
     assert(a)
   end
 
+  unless WINDOWS
+    # On Windows an error is raised when opening a directory instead of when reading.
+    def test_read_directory
+      File.open('.', 'r') do |f|
+        assert_raise(Errno::EISDIR) { f.read }
+      end
+    end
+
+    def test_gets_directory
+      File.open('.', 'r') do |f|
+        assert_raise(Errno::EISDIR) { f.gets }
+      end
+    end
+  end
+
   if (WINDOWS)
     #JRUBY-2158
     def test_null_open_windows