screensaver

   1 #!/usr/bin/env python3
   2
   3 import argparse
   4 import sys
   5 import psutil
   6 import subprocess
   7 import os
   8
   9 screensavers = [
  10     # slock
  11     {'start': ['xss-lock','-l','--','/home/don/bin/locker'],
  12      'stop': ['pkill','-TERM','xss-lock'],
  13      'test': lambda : cmd_exists('xss-lock') and cmd_exists('/home/don//bin/locker'),
  14      'running': 'xss-lock',
  15     },
  16     # slock
  17     {'start': ['xautolock','-locker','slock'],
  18      'stop': ['xautolock','-exit'],
  19      'test': lambda : cmd_exists('xautolock') and cmd_exists('slock'),
  20      'running': 'xautolock',
  21     },
  22     # xscreensaver
  23     {'start' : ['XENVIRONMENT=~/.xscreensaver','/usr/bin/xscreensaver'],
  24      'stop' : ['xscreensaver-command','-exit'],
  25      'test' : lambda : cmd_exists('xscreensaver'),
  26      'running' : 'xscreensaver',
  27     },
  28     # xautolock
  29     {'start': ('xautolock','-notifier','true','-bell','0'),
  30      'stop': ('xautolock','-exit'),
  31      'test': lambda : cmd_exists('xautolock'),
  32      'running' : 'xautolock',
  33     },
  34 ]
  35
  36 #' Determine if named command exists on the path and is executable
  37 def cmd_exists (cmd):
  38     return True
  39
  40 def cmd_running (cmd):
  41     user = os.getuid()
  42     for proc in psutil.process_iter():
  43         if proc.name() == cmd and proc.is_running() and proc.uids()[0] == user:
  44             return True
  45     return False
  46
  47 def parse_arguments():
  48     """Parses the arguments for the screensaver command
  49     """
  50     parser = argparse.ArgumentParser(
  51         description="A command to turn on/off screesavers"
  52         )
  53     parser.add_argument('command',choices=('sleep','off','stop','on','start'))
  54     return parser.parse_args()
  55
  56 def fork(cmd):
  57     try:
  58         pid = os.fork()
  59         if pid > 0:
  60             # parent process so return
  61             return
  62     except OSError as e:
  63         print >>sys.stderr, "fork failed: %d (%s)" % (e.errno, e.strerror)
  64         sys.exit(1)
  65
  66     os.setsid()
  67     try:
  68         pid = os.fork()
  69         if pid > 0:
  70             # parent process so return
  71             return
  72     except OSError as e:
  73         print >>sys.stderr, "fork failed: %d (%s)" % (e.errno, e.strerror)
  74         sys.exit(1)
  75     subprocess.Popen(cmd)
  76     os._exit(os.EX_OK)
  77
  78 def fork_sleep_and_forget(delay,cmd):
  79     sleep(delay)
  80     fork(cmd)
  81
  82
  83 def should_stop(args):
  84     if args.command == 'stop' or args.command == 'off':
  85         return True
  86     return False
  87
  88 def should_start(args):
  89     if args.command == 'start' or args.command == 'on':
  90         return True
  91     return False
  92
  93 def should_sleep(args):
  94     if args.command == 'sleep' or args.command == 'pause':
  95         return True
  96     return False
  97
  98 args = parse_arguments()
  99
 100 for screensaver in screensavers:
 101     if screensaver['test']():
 102         if should_stop(args):
 103             if cmd_running(screensaver['running']):
 104                 fork(screensaver['stop'])
 105         elif should_start(args):
 106             if not cmd_running(screensaver['running']):
 107                 fork(screensaver['start'])
 108         elif should_sleep(args):
 109             if cmd_running(screensaver['running']):
 110                 fork(screensaver['stop'])
 111             fork_sleep_and_forget(args.sleep,screensaver['start'])
 112         else:
 113             print >>sys.stderr,"Unknown command"
 114         exit(0)
 115
 116 print >> sys.stderr,"No screensaver"
 117