1 files changed, 58 insertions, 0 deletions
diff --git a/lib/yahns/worker.rb b/lib/yahns/worker.rb
new file mode 100644
index 0000000..980f7bd
--- /dev/null
+++ b/lib/yahns/worker.rb
@@ -0,0 +1,58 @@
+# -*- 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)
+class Yahns::Worker # :nodoc:
+  attr_accessor :nr
+  attr_reader :to_io
+
+  def initialize(nr)
+    @nr = nr
+    @to_io, @wr = Kgio::Pipe.new
+  end
+
+  def atfork_child
+    @wr = @wr.close # nil @wr to save space in worker process
+  end
+
+  def atfork_parent
+    @to_io = @to_io.close
+    self
+  end
+
+  # used in the worker process.
+  # This causes the worker to gracefully exit if the master
+  # dies unexpectedly.
+  def yahns_step
+    @to_io.kgio_tryread(11) == nil and Process.kill(:QUIT, $$)
+    :wait_readable
+  end
+
+  # worker objects may be compared to just plain Integers
+  def ==(other_nr) # :nodoc:
+    @nr == other_nr
+  end
+
+  # Changes the worker process to the specified +user+ and +group+
+  # This is only intended to be called from within the worker
+  # process from the +after_fork+ hook.  This should be called in
+  # the +after_fork+ hook after any privileged functions need to be
+  # run (e.g. to set per-worker CPU affinity, niceness, etc)
+  #
+  # Any and all errors raised within this method will be propagated
+  # directly back to the caller (usually the +after_fork+ hook.
+  # These errors commonly include ArgumentError for specifying an
+  # invalid user/group and Errno::EPERM for insufficient privileges
+  def user(user, group = nil)
+    # we do not protect the caller, checking Process.euid == 0 is
+    # insufficient because modern systems have fine-grained
+    # capabilities.  Let the caller handle any and all errors.
+    uid = Etc.getpwnam(user).uid
+    gid = Etc.getgrnam(group).gid if group
+    Yahns::Log.chown_all(uid, gid)
+    if gid && Process.egid != gid
+      Process.initgroups(user, gid)
+      Process::GID.change_privilege(gid)
+    end
+    Process.euid != uid and Process::UID.change_privilege(uid)
+  end
+end