__author__ = "Chad J. Schroeder"
__copyright__ = "Copyright (C) 2005 Chad J. Schroeder"

__revision__ = "$Id$"
__version__ = "0.2"

# Standard Python modules.
import os               # Miscellaneous OS interfaces.
import sys              # System-specific parameters and functions.

UMASK = 0
WORKDIR = "/"

# Default maximum for the number of available file descriptors.
MAXFD = 1024

# The standard I/O file descriptors are redirected to /dev/null by default.
# If you need to debug the launching of daemons, direct to a file instead.
if (hasattr(os, "devnull")):
   REDIRECT_TO = os.devnull
   # REDIRECT_TO= "/Users/terri/daemon.txt"
else:
   REDIRECT_TO = "/dev/null"
   # REDIRECT_TO= "/Users/terri/daemon.txt"

def createDaemon():
   """Detach a process from the controlling terminal and run it in the
   background as a daemon.
   """
   try:
      pid = os.fork()
   except OSError, e:
      raise Exception, "%s [%d]" % (e.strerror, e.errno)

   if (pid == 0):	# The first child.
      os.setsid()
      try:
         pid = os.fork()	# Fork a second child.
      except OSError, e:
         raise Exception, "%s [%d]" % (e.strerror, e.errno)

      if (pid == 0):	# The second child.
         os.chdir(WORKDIR)
         os.umask(UMASK)
      else:
         # exit() or _exit()?  See comment in original version in svn.
         os._exit(0)	
   else:
      os._exit(0)	# Exit parent of the first child.

   import resource		# Resource usage information.
   maxfd = resource.getrlimit(resource.RLIMIT_NOFILE)[1]
   if (maxfd == resource.RLIM_INFINITY):
      maxfd = MAXFD
   # Iterate through and close all file descriptors.
   for fd in range(0, maxfd):
      try:
         os.close(fd)
      except OSError:	# ERROR, fd wasn't open to begin with (ignored)
         pass

   os.open(REDIRECT_TO, os.O_RDWR | os.O_CREAT)	# standard input (0)
   # Duplicate standard input to standard output and standard error.
   os.dup2(0, 1)			# standard output (1)
   os.dup2(0, 2)			# standard error (2)

   return(0)

if __name__ == "__main__":

   if len(sys.argv) < 2 or ((sys.argv[1] != "registry") and (sys.argv[1] != "propsvc")):
      sys.exit('Expecting "registry" or "propsvc" as argument')
   service = sys.argv[1]
   cipresRoot = os.environ.get('CIPRES_ROOT')
   if not cipresRoot:
       sys.exit('CIPRES_ROOT env var must be set')
   try:
      retCode = createDaemon()
   except:
      sys.exit(1)

   # The code, as is, will create a new file in the root directory, when
   # executed with superuser privileges.  The file will contain the following
   # daemon related process parameters: return code, process ID, parent
   # process group ID, session ID, user ID, effective user ID, real group ID,
   # and the effective group ID.  Notice the relationship between the daemon's 
   # process ID, process group ID, and its parent's process ID.

   # try:
      # open("/Users/terri/daemon.log", "w+").write(procParams + "\n")
   # except:
      # sys.exit(2)
   
   import subprocess
   jarfile = os.path.join(cipresRoot, 'lib', 'cipres', 'cipres-classpath.jar')
   print 'jarfile is ', jarfile 
   if service == 'registry': 
       pid = subprocess.Popen(["java", "-DfixedPort=1", "-ea", "-classpath", jarfile, "org.cipres.registry.RegistryApp" ]).pid
   else:
       pid = subprocess.Popen(["java", "-ea", "-classpath", jarfile, "org.cipres.properties.PropertiesApp" ]).pid
   print 'launched ', service, ' on ', pid
   sys.exit(retCode)