worker-less server should not waitpid indiscriminately

We must not reap processes we did not spawn if we're not using a
master/worker configuration.  This may break applications which
depend on waitpid themselves.  However we still trap SIGCHLD
currently.  In the future, we could switch our notification
model mode to be compatible with apps which depend on SIGCHLD or
might indiscriminately on children (which might prevent us from
knowing about SIGCHLD).

2 files changed, 31 insertions, 22 deletions

diff --git a/lib/yahns/server.rb b/lib/yahns/server.rb
index 898be2c..9eb5378 100644
--- a/lib/yahns/server.rb
+++ b/lib/yahns/server.rb
@@ -412,6 +412,15 @@ class Yahns::Server # :nodoc:
     end
   end
 
+  def reap_reexec
+    @reexec_pid > 0 or return
+    wpid, status = Process.waitpid2(@reexec_pid, Process::WNOHANG)
+    wpid or return
+    @logger.error "reaped #{status.inspect} exec()-ed"
+    @reexec_pid = 0
+    self.pid = @pid.chomp('.oldbin') if @pid
+  end
+
   def sp_sig_handle(alive)
     @sev.kgio_wait_readable(alive ? nil : 0.01)
     @sev.yahns_step
@@ -419,7 +428,7 @@ class Yahns::Server # :nodoc:
     when :QUIT, :TERM, :INT
       return quit_enter(alive)
     when :CHLD
-      reap_all
+      reap_reexec
     when :USR1
       usr1_reopen('')
     when :USR2
@@ -456,25 +465,4 @@ class Yahns::Server # :nodoc:
   ensure
     quit_finish
   end
-
-  # reaps all unreaped workers/reexec processes
-  def reap_all
-    begin
-      wpid, status = Process.waitpid2(-1, Process::WNOHANG)
-      wpid or return
-      if @reexec_pid == wpid
-        @logger.error "reaped #{status.inspect} exec()-ed"
-        @reexec_pid = 0
-        self.pid = @pid.chomp('.oldbin') if @pid
-        proc_name('master') if @worker_processes
-      else
-        worker = @workers.delete(wpid)
-        desc = worker ? "worker=#{worker.nr}" : "(unknown)"
-        m = "reaped #{status.inspect} #{desc}"
-        status.success? ? @logger.info(m) : @logger.error(m)
-      end
-    rescue Errno::ECHILD
-      return
-    end while true
-  end
 end
diff --git a/lib/yahns/server_mp.rb b/lib/yahns/server_mp.rb
index 1e2f1c8..115f94a 100644
--- a/lib/yahns/server_mp.rb
+++ b/lib/yahns/server_mp.rb
@@ -164,4 +164,25 @@ module Yahns::ServerMP # :nodoc:
     end
     alive
   end
+
+  # reaps all unreaped workers/reexec processes
+  def reap_all
+    begin
+      wpid, status = Process.waitpid2(-1, Process::WNOHANG)
+      wpid or return
+      if @reexec_pid == wpid
+        @logger.error "reaped #{status.inspect} exec()-ed"
+        @reexec_pid = 0
+        self.pid = @pid.chomp('.oldbin') if @pid
+        proc_name('master')
+      else
+        worker = @workers.delete(wpid)
+        desc = worker ? "worker=#{worker.nr}" : "(unknown)"
+        m = "reaped #{status.inspect} #{desc}"
+        status.success? ? @logger.info(m) : @logger.error(m)
+      end
+    rescue Errno::ECHILD
+      return
+    end while true
+  end
 end