Suggested fix :
   Php fastcgi parent process install signals and inside signal handler it calls
exit. I think it is not wise to call complicated stuff like php_module_shutdown
inside signal handler so in my suggested fix, I set the variable exitsignal to 1.
When parent will come out of wait call, it should first invoke cleanup functions
and then call exit.

--- sapi/cgi/cgi_main.c_orig	2008-04-09 02:16:40.000000000 -0700
+++ sapi/cgi/cgi_main.c	2008-07-02 18:56:44.968570000 -0700
@@ -103,6 +103,12 @@
  */
 static int parent = 1;
 
+/* Did parent received exit signals SIG_TERM/SIG_INT/SIG_QUIT */
+static int exitsignal = 0;
+
+/* Is Parent waiting for children to exit */
+static int parentwaiting = 0;
+
 /**
  * Process group
  */
@@ -1151,9 +1157,13 @@
 	/* Kill all the processes in our process group */
 	kill(-pgroup, SIGTERM);
 #endif
-
 	/* We should exit at this point, but MacOSX doesn't seem to */
-	exit(0);
+	if (parent && parentwaiting) {
+		exitsignal = 1;
+	}
+	else {
+		exit(0);
+	}
 }
 #endif
 
@@ -1557,8 +1567,15 @@
 #ifdef DEBUG_FASTCGI
 				fprintf(stderr, "Wait for kids, pid %d\n", getpid());
 #endif
+				parentwaiting = 1;
 				while (wait(&status) < 0) {
 				}
+				if (exitsignal) {
+					SG(server_context) = NULL;
+					php_module_shutdown(TSRMLS_C);
+					sapi_shutdown();
+					exit(0);
+				}
 				running--;
 			}
 		}

Dmitry, this patch looks okay to me..can I have a second opinion from you? :)

This bug has been fixed in CVS.

Snapshots of the sources are packaged every three hours; this change
will be in the next snapshot. You can grab the snapshot at
http://snaps.php.net/.
 
Thank you for the report, and for helping us make PHP better.