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| | # -*- encoding: binary -*-
# Copyright (C) 2013, Eric Wong <normalperson@yhbt.net> and all contributors
# License: GPLv3 or later (https://www.gnu.org/licenses/gpl-3.0.txt)
module Yahns::Daemon # :nodoc:
# We don't do a lot of standard daemonization stuff:
# * umask is whatever was set by the parent process at startup
# and can be set in config.ru and config_file, so making it
# 0000 and potentially exposing sensitive log data can be bad
# policy.
# * don't bother to chdir("/") here since yahns is designed to
# run inside APP_ROOT. Yahns will also re-chdir() to
# the directory it was started in when being re-executed
# to pickup code changes if the original deployment directory
# is a symlink or otherwise got replaced.
def self.daemon(yahns_server)
$stdin.reopen("/dev/null")
# We only start a new process group if we're not being reexecuted
# and inheriting file descriptors from our parent
unless ENV['YAHNS_FD']
# grandparent - reads pipe, exits when master is ready
# \_ parent - exits immediately ASAP
# \_ yahns master - writes to pipe when ready
# We cannot use Yahns::Sigevent (eventfd) here because we need
# to detect EOF on unexpected death, not just read/write
rd, wr = IO.pipe
rd.close_on_exec = wr.close_on_exec = true
grandparent = $$
if fork
wr.close # grandparent does not write
else
rd.close # yahns master does not read
Process.setsid
exit if fork # parent dies now
end
if grandparent == $$
# this will block until Server#join runs (or it dies)
master_pid = (rd.readpartial(16) rescue nil).to_i
unless master_pid > 1
warn "master failed to start, check stderr log for details"
exit!(1)
end
exit 0
else # yahns master process
yahns_server.daemon_pipe = wr
end
end
# $stderr/$stderr can/will be redirected separately in the Yahns config
end
end
|