pkgdistcache/pkgdistcache-daemon

   1 #!/usr/bin/python2
   2 # coding: utf-8
   3 #
   4 # pkgdistcache daemon v0.3.1
   5 # by Alessio Bianchi <venator85@gmail.com>
   6 #
   7 # Daemon code by Chad J. Schroeder
   8 # http://code.activestate.com/recipes/278731/
   9 #
  10
  11 import sys
  12 import os
  13 import os.path
  14 import subprocess
  15 import string
  16 import avahi
  17 import dbus
  18 import gobject
  19 import dbus.glib
  20 import SimpleHTTPServer
  21 import BaseHTTPServer
  22 import signal
  23
  24 avahi_service = None
  25
  26 def terminate(signum, frame):
  27         avahi_service.unpublish()
  28         sys.exit(0)
  29
  30 # Run a command synchronously, redirecting stdout and stderr to strings
  31 def runcmd(cmd, cwd=None):
  32         pipe = subprocess.Popen(cmd, shell=True, cwd=cwd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
  33         (stdout, stderr) = pipe.communicate()   # wait for process to terminate and return stdout and stderr
  34         return {'stdout': stdout.strip(), 'stderr': stderr.strip(), 'retcode': pipe.returncode}
  35
  36 # Detach a process from the controlling terminal and run it in the background as a daemon
  37 def daemonize():
  38         try:
  39                 pid = os.fork()
  40         except OSError, e:
  41                 raise Exception, "%s [%d]" % (e.strerror, e.errno)
  42
  43         if (pid == 0):  # The first child.
  44                 os.setsid()
  45                 try:
  46                         pid = os.fork() # Fork a second child.
  47                 except OSError, e:
  48                         raise Exception, "%s [%d]" % (e.strerror, e.errno)
  49
  50                 if (pid != 0):  # The second child.
  51                         os._exit(0)     # Exit parent (the first child) of the second child.
  52         else:
  53                 os._exit(0)     # Exit parent of the first child.
  54
  55         import resource         # Resource usage information.
  56         maxfd = resource.getrlimit(resource.RLIMIT_NOFILE)[1]
  57         if (maxfd == resource.RLIM_INFINITY):
  58                 maxfd = 1024
  59
  60         # Iterate through and close all file descriptors.
  61         for fd in range(0, maxfd):
  62                 try:
  63                         os.close(fd)
  64                 except OSError: # ERROR, fd wasn't open to begin with (ignored)
  65                         pass
  66
  67         # The standard I/O file descriptors are redirected to /dev/null by default.
  68         os.open("/dev/null", os.O_RDWR) # standard input (0)
  69         os.dup2(0, 1)                   # standard output (1)
  70         os.dup2(0, 2)                   # standard error (2)
  71         return(0)
  72
  73 class AvahiPublisher:
  74         #Based on http://avahi.org/wiki/PythonPublishExample
  75         def __init__(self, name, stype, host, port):
  76                 self.name = name
  77                 self.stype = stype
  78                 self.domain = 'local'
  79                 self.host = host
  80                 self.port = port
  81                 self.systemBus = dbus.SystemBus()
  82                 self.server = dbus.Interface(self.systemBus.get_object(avahi.DBUS_NAME, avahi.DBUS_PATH_SERVER), avahi.DBUS_INTERFACE_SERVER)
  83
  84         def publish(self):
  85                 self.group = dbus.Interface(
  86                         self.systemBus.get_object(avahi.DBUS_NAME, self.server.EntryGroupNew()),
  87                         avahi.DBUS_INTERFACE_ENTRY_GROUP)
  88
  89                 self.group.AddService(
  90                         avahi.IF_UNSPEC,        #interface
  91                         avahi.PROTO_UNSPEC,     #protocol
  92                         dbus.UInt32(0),         #flags
  93                         self.name, self.stype,
  94                         self.domain, self.host,
  95                         dbus.UInt16(self.port),
  96                         avahi.string_array_to_txt_array([]))
  97                 self.group.Commit()
  98
  99         def unpublish(self):
 100                 self.group.Reset()
 101
 102 def main(args):
 103         import optparse
 104         parser = optparse.OptionParser()
 105         parser.add_option("-F", "--foreground", action="store_true", dest="no_daemon", default=False,
 106                               help="run pkgdistcache-daemon in foreground")
 107         (options, args) = parser.parse_args()
 108         if options.no_daemon == False:
 109                 # fork daemon in background
 110                 daemonize()
 111
 112         # load configuration file
 113         conf_file = '/etc/pkgdistcache.conf'
 114         if os.path.isfile(conf_file):
 115                 config = eval(open(conf_file).read())
 116         else:
 117                 printerr("Config file " + conf_file + " not found")
 118                 return 2
 119
 120         port = config['port']
 121         hostname = runcmd('hostname')['stdout']
 122         global avahi_service
 123         avahi_service = AvahiPublisher(hostname, '_pkgdistcache._tcp', '', port)
 124         avahi_service.publish()
 125
 126         os.chdir('/var/cache/pacman/pkg')
 127         handler = SimpleHTTPServer.SimpleHTTPRequestHandler
 128         httpd = BaseHTTPServer.HTTPServer(('', port), handler)
 129
 130         try:
 131                 httpd.serve_forever()
 132         except KeyboardInterrupt:
 133                 avahi_service.unpublish()
 134
 135         return 0
 136
 137 if __name__ == '__main__':
 138         signal.signal(signal.SIGTERM, terminate)
 139         main(sys.argv)