From d3e8771aedeeead1b250f7a6849644092399b883 Mon Sep 17 00:00:00 2001
From: Peter Surda <surda@economicsofbitcoin.com>
Date: Thu, 30 Jun 2016 13:07:28 +0200
Subject: [PATCH] Lock file fixes

- daemon mode lock file didn't work correctly in the last commit
---
 src/bitmessagemain.py |  3 +++
 src/singleton.py      | 20 +++++++++++++++-----
 2 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/src/bitmessagemain.py b/src/bitmessagemain.py
index aae46f2c..f67f6619 100755
--- a/src/bitmessagemain.py
+++ b/src/bitmessagemain.py
@@ -255,10 +255,13 @@ class Main:
     def daemonize(self):
         if os.fork():
             exit(0)
+        shared.thisapp.lock() # relock
         os.umask(0)
         os.setsid()
         if os.fork():
             exit(0)
+        shared.thisapp.lock() # relock
+        shared.thisapp.lockPid = None # indicate we're the final child
         sys.stdout.flush()
         sys.stderr.flush()
         si = file('/dev/null', 'r')
diff --git a/src/singleton.py b/src/singleton.py
index a3a77fd7..8bf7ed01 100644
--- a/src/singleton.py
+++ b/src/singleton.py
@@ -23,6 +23,7 @@ class singleinstance:
         self.initialized = False
         self.counter = 0
         self.daemon = daemon
+        self.lockPid = None
         self.lockfile = os.path.normpath(os.path.join(shared.appdata, 'singleton%s.lock' % flavor_id))
 
         if not self.daemon and not shared.curses:
@@ -30,6 +31,14 @@ class singleinstance:
             import bitmessageqt
             bitmessageqt.init()
 
+        self.lock()
+
+        self.initialized = True
+        atexit.register(self.cleanup)
+
+    def lock(self):
+        if self.lockPid is None:
+            self.lockPid = os.getpid()
         if sys.platform == 'win32':
             try:
                 # file already exists, we try to remove (in case previous execution was interrupted)
@@ -46,18 +55,19 @@ class singleinstance:
         else:  # non Windows
             self.fp = open(self.lockfile, 'w')
             try:
-                fcntl.lockf(self.fp, fcntl.LOCK_EX | fcntl.LOCK_NB)
+                if self.daemon and self.lockPid != os.getpid():
+                    fcntl.lockf(self.fp, fcntl.LOCK_EX) # wait for parent to finish
+                else:
+                    fcntl.lockf(self.fp, fcntl.LOCK_EX | fcntl.LOCK_NB)
+                self.lockPid = os.getpid()
             except IOError:
                 print 'Another instance of this application is already running'
                 sys.exit(-1)
-        self.initialized = True
-        atexit.register(self.cleanup)
 
     def cleanup(self):
         if not self.initialized:
             return
-        self.counter += 1
-        if self.daemon and self.counter < 3:
+        if self.daemon and self.lockPid == os.getpid():
             # these are the two initial forks while daemonizing
             return
         print "Cleaning up lockfile"