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#
# Author:: AJ Christensen (<aj@junglist.gen.nz>)
# Copyright:: Copyright (c) 2008 Opscode, Inc.
# License:: Apache License, Version 2.0
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# I love you Merb (lib/merb-core/server.rb)
require 'chef/config'
require 'etc'
class Chef
class Daemon
class << self
attr_accessor :name
# Daemonize the current process, managing pidfiles and process uid/gid
#
# === Parameters
# name<String>:: The name to be used for the pid file
#
def daemonize(name)
@name = name
pid = pid_from_file
unless running?
remove_pid_file()
Chef::Log.info("Daemonizing..")
begin
exit if fork
Process.setsid
exit if fork
Chef::Log.info("Forked, in #{Process.pid}. Privileges: #{Process.euid} #{Process.egid}")
File.umask Chef::Config[:umask]
$stdin.reopen("/dev/null")
$stdout.reopen("/dev/null", "a")
$stderr.reopen($stdout)
save_pid_file
at_exit { remove_pid_file }
rescue NotImplementedError => e
Chef::Application.fatal!("There is no fork: #{e.message}")
end
else
Chef::Application.fatal!("Chef is already running pid #{pid}")
end
end
# Check if Chef is running based on the pid_file
# ==== Returns
# Boolean::
# True if Chef is running
# False if Chef is not running
#
def running?
if pid_from_file.nil?
false
else
Process.kill(0, pid_from_file)
true
end
rescue Errno::ESRCH, Errno::ENOENT
false
rescue Errno::EACCES => e
Chef::Application.fatal!("You don't have access to the PID file at #{pid_file}: #{e.message}")
end
# Check if this process if forked from a Chef daemon
# ==== Returns
# Boolean::
# True if this process is forked
# False if this process is not forked
#
def forked?
if running? and Process.ppid == pid_from_file.to_i
# chef daemon is running and this process is a child of it
true
elsif not running? and Process.ppid == 1
# an orphaned fork, its parent becomes init, launchd, etc. after chef daemon dies
true
else
false
end
end
# Gets the pid file for @name
# ==== Returns
# String::
# Location of the pid file for @name
def pid_file
Chef::Config[:pid_file] or "/tmp/#{@name}.pid"
end
# Suck the pid out of pid_file
# ==== Returns
# Integer::
# The PID from pid_file
# nil::
# Returned if the pid_file does not exist.
#
def pid_from_file
File.read(pid_file).chomp.to_i
rescue Errno::ENOENT, Errno::EACCES
nil
end
# Store the PID on the filesystem
# This uses the Chef::Config[:pid_file] option, or "/tmp/name.pid" otherwise
#
def save_pid_file
file = pid_file
begin
FileUtils.mkdir_p(File.dirname(file))
rescue Errno::EACCES => e
Chef::Application.fatal!("Failed store pid in #{File.dirname(file)}, permission denied: #{e.message}")
end
begin
File.open(file, "w") { |f| f.write(Process.pid.to_s) }
rescue Errno::EACCES => e
Chef::Application.fatal!("Couldn't write to pidfile #{file}, permission denied: #{e.message}")
end
end
# Delete the PID from the filesystem
def remove_pid_file
if not forked? then
FileUtils.rm(pid_file) if File.exists?(pid_file)
end
end
# Change process user/group to those specified in Chef::Config
#
def change_privilege
Dir.chdir("/")
if Chef::Config[:user] and Chef::Config[:group]
Chef::Log.info("About to change privilege to #{Chef::Config[:user]}:#{Chef::Config[:group]}")
_change_privilege(Chef::Config[:user], Chef::Config[:group])
elsif Chef::Config[:user]
Chef::Log.info("About to change privilege to #{Chef::Config[:user]}")
_change_privilege(Chef::Config[:user])
end
end
# Change privileges of the process to be the specified user and group
#
# ==== Parameters
# user<String>:: The user to change the process to.
# group<String>:: The group to change the process to.
#
# ==== Alternatives
# If group is left out, the user will be used (changing to user:user)
#
def _change_privilege(user, group=user)
uid, gid = Process.euid, Process.egid
begin
target_uid = Etc.getpwnam(user).uid
rescue ArgumentError => e
Chef::Application.fatal!("Failed to get UID for user #{user}, does it exist? #{e.message}")
return false
end
begin
target_gid = Etc.getgrnam(group).gid
rescue ArgumentError => e
Chef::Application.fatal!("Failed to get GID for group #{group}, does it exist? #{e.message}")
return false
end
if (uid != target_uid) or (gid != target_gid)
Process.initgroups(user, target_gid)
Process::GID.change_privilege(target_gid)
Process::UID.change_privilege(target_uid)
end
true
rescue Errno::EPERM => e
Chef::Application.fatal!("Permission denied when trying to change #{uid}:#{gid} to #{target_uid}:#{target_gid}. #{e.message}")
end
end
end
end
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