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