From ca8efbf65730d24b31023cb69921de654a8d0e8f Mon Sep 17 00:00:00 2001
From: Vishvananda Ishaya <vishvananda@gmail.com>
Date: Thu, 20 Sep 2012 07:46:04 -0700
Subject: [PATCH] Reset SIGPIPE handler when calling Popen

Python ignores SIGPIPE on startup, because it prefers to check every
write and raise an IOError exception rather than taking the signal. Most
Unix subprocesses don't expect to work this way. This patch (adapted
from Colin Watson's post at http://tinyurl.com/2a7mzh5) sets SIGPIPE
back to the default action.
---
 websockify/websocketproxy.py | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/websockify/websocketproxy.py b/websockify/websocketproxy.py
index 13f6582..f43b83c 100755
--- a/websockify/websocketproxy.py
+++ b/websockify/websocketproxy.py
@@ -11,7 +11,7 @@ as taken from http://docs.python.org/dev/library/ssl.html#certificates
 
 '''
 
-import socket, optparse, time, os, sys, subprocess
+import signal, socket, optparse, time, os, sys, subprocess
 from select import select
 import websocket
 try:    from urllib.parse import parse_qs, urlparse
@@ -87,7 +87,7 @@ Traffic Legend:
         self.wrap_times.append(time.time())
         self.wrap_times.pop(0)
         self.cmd = subprocess.Popen(
-                self.wrap_cmd, env=os.environ)
+                self.wrap_cmd, env=os.environ, preexec_fn=_subprocess_setup)
         self.spawn_message = True
 
     def started(self):
@@ -144,7 +144,7 @@ Traffic Legend:
                 else:
                     self.run_wrap_cmd()
 
-    # 
+    #
     # Routines above this point are run in the master listener
     # process.
     #
@@ -171,7 +171,7 @@ Traffic Legend:
         else:
             msg = "connecting to: %s:%s" % (
                                     self.target_host, self.target_port)
-        
+
         if self.ssl_target:
             msg += " (using SSL)"
         self.msg(msg)
@@ -291,6 +291,13 @@ Traffic Legend:
                         self.target_host, self.target_port))
                     raise self.CClose(closed['code'], closed['reason'])
 
+
+def _subprocess_setup():
+    # Python installs a SIGPIPE handler by default. This is usually not what
+    # non-Python successfulbprocesses expect.
+    signal.signal(signal.SIGPIPE, signal.SIG_DFL)
+
+
 def websockify_init():
     usage = "\n    %prog [options]"
     usage += " [source_addr:]source_port [target_addr:target_port]"
@@ -349,7 +356,7 @@ def websockify_init():
 
     if not websocket.ssl and opts.ssl_target:
         parser.error("SSL target requested and Python SSL module not loaded.");
-        
+
     if opts.ssl_only and not os.path.exists(opts.cert):
         parser.error("SSL only and %s not found" % opts.cert)