1 files changed, 62 insertions, 0 deletions
diff --git a/lib/internal/process.js b/lib/internal/process.js
index c435c2e871..5b6e56fa9a 100644
--- a/lib/internal/process.js
+++ b/lib/internal/process.js
@@ -145,7 +145,69 @@ function setupKillAndExit() {
       process._exiting = true;
       process.emit('exit', process.exitCode || 0);
     }
+
+    // Flush stdio streams prior to exit.
+    // `flushSync` not present if stream redirected to file in shell.
+    flushSync(process.stdout);
+    flushSync(process.stderr);
+
     process.reallyExit(process.exitCode || 0);
+
+    function flushSync(stream) {
+
+      // Behavior of this function outside of process.exit() is undefined
+      // due to the following factors:
+      // * Stream fd may be blocking after this call.
+      // * In the event of an incomplete flush pending buffered write
+      //   requests may be truncated.
+      // * No return code.
+
+      if (stream._writev)
+        return;
+
+      var handle = stream._handle;
+      if (!handle || !handle.flushSync)
+        return;
+
+      var fd = handle.fd;
+      if (typeof fd !== 'number' || fd < 0)
+        return;
+
+      // FIXME: late module resolution avoids cross require problem
+      const fs = require('fs');
+
+      const Buffer = require('buffer');
+
+      // Queued libuv writes must be flushed first.
+      // Note: fd will set to blocking after handle.flushSync()
+      if (handle.flushSync() !== 0) {
+        // bad fd or write queue for libuv stream not entirely flushed
+        return;
+      }
+
+      // then the queued stream chunks can be flushed
+      var state = stream._writableState;
+      var entry = state.bufferedRequest;
+      while (entry) {
+        var chunk = entry.chunk;
+        if (!(chunk instanceof Buffer)) {
+          chunk = Buffer.from(chunk, entry.encoding);
+        }
+        // Note: fd is blocking at this point
+        var written = fs.writeSync(fd, chunk, 0, chunk.length);
+        if (written !== chunk.length) {
+          // stream chunk not flushed entirely - stop writing.
+          // FIXME: buffered request queue should be repaired here
+          //        rather than being truncated after loop break
+          break;
+        }
+        entry = entry.next;
+      }
+
+      state.bufferedRequestCount = 0;
+      state.bufferedRequest = null;
+      state.lastBufferedRequest = null;
+    }
   };
 
   process.kill = function(pid, sig) {