From 2e645039c2ea7a7e0684e46799db2a901a5d3cae Mon Sep 17 00:00:00 2001
From: Arturo Filastò <hellais@torproject.org>
Date: Tue, 23 Aug 2011 01:33:13 +0200
Subject: Fix #3790 Add a daemon class and make tor web ui run as such.

---
 packages/torouter-web/src/daemon.py | 129 ++++++++++++++++++++++++++++++++++++
 1 file changed, 129 insertions(+)
 create mode 100644 packages/torouter-web/src/daemon.py

(limited to 'packages/torouter-web/src/daemon.py')

diff --git a/packages/torouter-web/src/daemon.py b/packages/torouter-web/src/daemon.py
new file mode 100644
index 0000000..4ccc15c
--- /dev/null
+++ b/packages/torouter-web/src/daemon.py
@@ -0,0 +1,129 @@
+#!/usr/bin/env python
+
+import sys, os, time, atexit
+from signal import SIGTERM 
+
+class Daemon:
+	"""
+	A generic daemon class.
+	
+	Usage: subclass the Daemon class and override the run() method
+	"""
+	def __init__(self, pidfile, stdin='/dev/null', stdout='/dev/null', stderr='/dev/null'):
+		self.stdin = stdin
+		self.stdout = stdout
+		self.stderr = stderr
+		self.pidfile = pidfile
+	
+	def daemonize(self):
+		"""
+		do the UNIX double-fork magic, see Stevens' "Advanced 
+		Programming in the UNIX Environment" for details (ISBN 0201563177)
+		http://www.erlenstar.demon.co.uk/unix/faq_2.html#SEC16
+		"""
+		try: 
+			pid = os.fork() 
+			if pid > 0:
+				# exit first parent
+				sys.exit(0) 
+		except OSError, e: 
+			sys.stderr.write("fork #1 failed: %d (%s)\n" % (e.errno, e.strerror))
+			sys.exit(1)
+	
+		# decouple from parent environment
+		#os.chdir("/") 
+		os.setsid() 
+		os.umask(0) 
+	
+		# do second fork
+		try: 
+			pid = os.fork() 
+			if pid > 0:
+				# exit from second parent
+				sys.exit(0) 
+		except OSError, e: 
+			sys.stderr.write("fork #2 failed: %d (%s)\n" % (e.errno, e.strerror))
+			sys.exit(1) 
+	
+		# redirect standard file descriptors
+		sys.stdout.flush()
+		sys.stderr.flush()
+		si = file(self.stdin, 'r')
+		so = file(self.stdout, 'a+')
+		se = file(self.stderr, 'a+', 0)
+		os.dup2(si.fileno(), sys.stdin.fileno())
+		os.dup2(so.fileno(), sys.stdout.fileno())
+		os.dup2(se.fileno(), sys.stderr.fileno())
+	
+		# write pidfile
+		atexit.register(self.delpid)
+		pid = str(os.getpid())
+		file(self.pidfile,'w+').write("%s\n" % pid)
+	
+	def delpid(self):
+		os.remove(self.pidfile)
+
+	def start(self):
+		"""
+		Start the daemon
+		"""
+		# Check for a pidfile to see if the daemon already runs
+		try:
+			pf = file(self.pidfile,'r')
+			pid = int(pf.read().strip())
+			pf.close()
+		except IOError:
+			pid = None
+	
+		if pid:
+			message = "pidfile %s already exist. Daemon already running?\n"
+			sys.stderr.write(message % self.pidfile)
+			sys.exit(1)
+		
+		# Start the daemon
+		self.daemonize()
+		self.run()
+
+	def stop(self):
+		"""
+		Stop the daemon
+		"""
+		# Get the pid from the pidfile
+		try:
+			pf = file(self.pidfile,'r')
+			pid = int(pf.read().strip())
+			pf.close()
+		except IOError:
+			pid = None
+	
+		if not pid:
+			message = "pidfile %s does not exist. Daemon not running?\n"
+			sys.stderr.write(message % self.pidfile)
+			return # not an error in a restart
+
+		# Try killing the daemon process	
+		try:
+			while 1:
+				os.kill(pid, SIGTERM)
+				time.sleep(0.1)
+		except OSError, err:
+			err = str(err)
+			if err.find("No such process") > 0:
+				if os.path.exists(self.pidfile):
+					os.remove(self.pidfile)
+			else:
+				print str(err)
+				sys.exit(1)
+
+	def restart(self):
+		"""
+		Restart the daemon
+		"""
+		self.stop()
+		self.start()
+
+	def run(self):
+		"""
+		You should override this method when you subclass Daemon. It will be called after the process has been
+		daemonized by start() or restart().
+		"""
-- 
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