59 lines
1.9 KiB
Python
59 lines
1.9 KiB
Python
import os
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import sys
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if os.name == 'posix':
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def become_daemon(our_home_dir='.', out_log='/dev/null',
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err_log='/dev/null', umask=022):
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"Robustly turn into a UNIX daemon, running in our_home_dir."
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# First fork
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try:
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if os.fork() > 0:
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sys.exit(0) # kill off parent
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except OSError as e:
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sys.stderr.write("fork #1 failed: (%d) %s\n" % (e.errno, e.strerror))
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sys.exit(1)
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os.setsid()
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os.chdir(our_home_dir)
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os.umask(umask)
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# Second fork
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try:
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if os.fork() > 0:
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os._exit(0)
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except OSError as e:
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sys.stderr.write("fork #2 failed: (%d) %s\n" % (e.errno, e.strerror))
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os._exit(1)
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si = open('/dev/null', 'r')
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so = open(out_log, 'a+', 0)
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se = open(err_log, 'a+', 0)
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os.dup2(si.fileno(), sys.stdin.fileno())
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os.dup2(so.fileno(), sys.stdout.fileno())
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os.dup2(se.fileno(), sys.stderr.fileno())
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# Set custom file descriptors so that they get proper buffering.
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sys.stdout, sys.stderr = so, se
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else:
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def become_daemon(our_home_dir='.', out_log=None, err_log=None, umask=022):
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"""
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If we're not running under a POSIX system, just simulate the daemon
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mode by doing redirections and directory changing.
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"""
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os.chdir(our_home_dir)
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os.umask(umask)
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sys.stdin.close()
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sys.stdout.close()
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sys.stderr.close()
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if err_log:
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sys.stderr = open(err_log, 'a', 0)
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else:
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sys.stderr = NullDevice()
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if out_log:
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sys.stdout = open(out_log, 'a', 0)
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else:
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sys.stdout = NullDevice()
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class NullDevice:
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"A writeable object that writes to nowhere -- like /dev/null."
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def write(self, s):
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pass
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