Class: DaemonChild

Inherits:
Object
  • Object
show all
Defined in:
lib/daemonchild.rb

Overview

Credits

Inspired by and based on Daemonize as distributed as part of Thomas Uehlinger’s Daemons gem.

Daemonize was written by Travis Whitton and is based on Perl’s Proc::Daemonize, which was written by Earl Hood.

Based on the Unix Programmer FAQ which is currently available www.faqs.org/faqs/unix-faq/programmer/faq/ (and other places I’m sure)

Constant Summary collapse

VERSION = 
'0.0.1'

Class Method Summary collapse

Class Method Details

.process_name ⇒ Object 



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# File 'lib/daemonchild.rb', line 61

def self.process_name
  $0
end

.process_name=(name) ⇒ Object 



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# File 'lib/daemonchild.rb', line 65

def self.process_name=(name)
  $0 = name
end

.spawn ⇒ Object 



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# File 'lib/daemonchild.rb', line 17

def self.spawn()
  # Exit fast if in app that presents itself as irb
  # as a rudimentary safety check.  if irb daemonizes and gets
  # /dev/null as STDIN, it chews up all the cpu trying to take input
  # but you really shouldn't daemonize irb anyway
  exit if $0 == 'irb'
  
  cwd = Dir.getwd

  # Fork so the parent can exit
  Process.fork and Process.exit

  # Become a process group and session group leader
  sid = Process.setsid

  # Fork so the session group leader can exit and we can not regain
  # a controlling terminal
  Process.fork and Process.exit

  # Return to original working directory
  Dir.chdir cwd
  
  # Give ourselves complete control over permissions of files we'd write
  File.umask 0

  # Close any open filehandles
  ObjectSpace.each_object(IO) do |io|
    begin
      io.close unless io.closed?
    rescue ::Exception
    end
  end

  # Reopen stdin, stdout, stdin to /dev/null
  [STDIN,STDOUT,STDERR].each do |io|
    begin
      io.reopen '/dev/null'
    rescue ::Exception
    end
  end

  return Process.pid
end

.stderr=(fp) ⇒ Object 



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# File 'lib/daemonchild.rb', line 77

def self.stderr=(fp)
  STDERR.reopen fp
end

.stdin=(fp) ⇒ Object 



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# File 'lib/daemonchild.rb', line 69

def self.stdin=(fp)
  STDIN.reopen fp
end

.stdout=(fp) ⇒ Object 



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# File 'lib/daemonchild.rb', line 73

def self.stdout=(fp)
  STDOUT.reopen fp
end