allow mpm to be note connections that are not TCP based.

CHANGES

@@ -1,6 +1,14 @@
                                                          -*- coding: utf-8 -*-
 Changes with Apache 2.5.1
 
+  *) mpm_event: Add optional hooks for modules that manage connections
+     outside the MPM accept loop (UDP connections) can be accounted for.
+     [Tarek Ibrahim <tareki pulsarxtech.com> <t1br4h1m gmail.com>]
+
+  *) mpm_event: Avoid crashes in setup_slave_conn() when handling
+     connections not managed by the MPM.
+     [Tarek Ibrahim <tareki pulsarxtech.com> <t1br4h1m gmail.com>]
+
   *) mod_proxy_beacon: Back-end reverse proxy servers can announce
      themselves and be auto-added to their front-end proxy balancer.
      [Jim Jagielski]

include/mpm_common.h

@@ -40,6 +40,7 @@
 #include "ap_config.h"
 #include "ap_mpm.h"
 #include "scoreboard.h"
+#include "apr_optional.h"
 
 #if APR_HAVE_NETINET_TCP_H
 #include <netinet/tcp.h>    /* for TCP_NODELAY */
@@ -560,6 +561,20 @@ AP_DECLARE_HOOK(void, child_stopped,
  */
 void mpm_common_pre_config(apr_pool_t *pconf);
 
+/**
+ * Hooks for modules to report connections the MPM did not accept itself.
+ *
+ * MPMs that wait for their connection count to drain before stopping a child
+ * need this so externally accepted connections keep the child alive until
+ * they finish.
+ *
+ * Call ap_mpm_note_extra_connection_added() when such a connection starts,
+ * and ap_mpm_note_extra_connection_removed() when it ends. These functions
+ * may be NULL if the active MPM does not implement them.
+ */
+APR_DECLARE_OPTIONAL_FN(void, ap_mpm_note_extra_connection_added, (void));
+APR_DECLARE_OPTIONAL_FN(void, ap_mpm_note_extra_connection_removed, (void));
+
 #ifdef __cplusplus
 }
 #endif

server/mpm/event/event.c

@@ -871,6 +871,21 @@ static apr_status_t decrement_connection_count(void *cs_)
     return APR_SUCCESS;
 }
 
+static void ap_mpm_note_extra_connection_added(void)
+{
+    apr_atomic_inc32(&connection_count);
+}
+
+static void ap_mpm_note_extra_connection_removed(void)
+{
+    int is_last_connection = !apr_atomic_dec32(&connection_count);
+
+    /* Wake a listener blocked waiting for connection_count to drain. */
+    if (listener_is_wakeable && is_last_connection && listener_may_exit) {
+        apr_pollset_wakeup(event_pollset);
+    }
+}
+
 static void notify_suspend(event_conn_state_t *cs)
 {
     ap_run_suspend_connection(cs->c, cs->r);
@@ -3876,6 +3891,10 @@ static void setup_slave_conn(conn_rec *c, void *csd)
     event_conn_state_t *cs;
 
     mcs = ap_get_module_config(c->master->conn_config, &mpm_event_module);
+    if (!mcs) {
+        /* Master connection is not managed by this MPM; nothing to inherit. */
+        return;
+    }
 
     cs = apr_pcalloc(c->pool, sizeof(*cs));
     cs->c = c;
@@ -3954,6 +3973,9 @@ static int event_pre_config(apr_pool_t * pconf, apr_pool_t * plog,
     const char *userdata_key = "mpm_event_module";
     int test_atomics = 0;
 
+    APR_REGISTER_OPTIONAL_FN(ap_mpm_note_extra_connection_added);
+    APR_REGISTER_OPTIONAL_FN(ap_mpm_note_extra_connection_removed);
+
     debug = ap_exists_config_define("DEBUG");
 
     if (debug) {

server/mpm/prefork/prefork.c

@@ -18,6 +18,7 @@
 #include "apr_portable.h"
 #include "apr_strings.h"
 #include "apr_thread_proc.h"
+#include "apr_atomic.h"
 #include "apr_signal.h"
 
 #define APR_WANT_STDIO
@@ -89,6 +90,7 @@
 
 /* config globals */
 
+static apr_uint32_t connection_count = 0;   /* Number of open connections */
 static int ap_daemons_to_start=0;
 static int ap_daemons_min_free=0;
 static int ap_daemons_max_free=0;
@@ -229,6 +231,11 @@ static void clean_child_exit_ex(int code, int from_signal)
     if (pchild) {
         if (!code && !from_signal) {
             ap_run_child_stopping(pchild, !retained->mpm->is_ungraceful);
+            if (!retained->mpm->is_ungraceful) {
+                while (apr_atomic_read32(&connection_count) > 0) {
+                    apr_sleep(apr_time_from_msec(100));
+                }
+            }
             ap_run_child_stopped(pchild, !retained->mpm->is_ungraceful);
         }
         apr_pool_destroy(pchild);
@@ -380,6 +387,16 @@ static void just_die(int sig)
 /* volatile because it's updated from a signal handler */
 static int volatile die_now = 0;
 
+static void ap_mpm_note_extra_connection_added(void)
+{
+    apr_atomic_inc32(&connection_count);
+}
+
+static void ap_mpm_note_extra_connection_removed(void)
+{
+    apr_atomic_dec32(&connection_count);
+}
+
 static void stop_listening(int sig)
 {
     retained->mpm->mpm_state = AP_MPMQ_STOPPING;
@@ -1321,6 +1338,9 @@ static int prefork_pre_config(apr_pool_t *p, apr_pool_t *plog, apr_pool_t *ptemp
     apr_status_t rv;
     const char *userdata_key = "mpm_prefork_module";
 
+    APR_REGISTER_OPTIONAL_FN(ap_mpm_note_extra_connection_added);
+    APR_REGISTER_OPTIONAL_FN(ap_mpm_note_extra_connection_removed);
+
     debug = ap_exists_config_define("DEBUG");
 
     if (debug) {

server/mpm/worker/worker.c

@@ -30,6 +30,7 @@
 #include "apr_thread_mutex.h"
 #include "apr_proc_mutex.h"
 #include "apr_poll.h"
+#include "apr_atomic.h"
 
 #include <stdlib.h>
 
@@ -117,6 +118,7 @@
  * Actual definitions of config globals
  */
 
+static apr_uint32_t connection_count = 0;   /* Number of open connections */
 static int threads_per_child = 0;     /* Worker threads per child */
 static int ap_daemons_to_start = 0;
 static int min_spare_threads = 0;
@@ -511,6 +513,16 @@ static void check_infinite_requests(void)
     }
 }
 
+static void ap_mpm_note_extra_connection_added(void)
+{
+    apr_atomic_inc32(&connection_count);
+}
+
+static void ap_mpm_note_extra_connection_removed(void)
+{
+    apr_atomic_dec32(&connection_count);
+}
+
 static void unblock_signal(int sig)
 {
     sigset_t sig_mask;
@@ -1328,6 +1340,12 @@ static void child_main(int child_num_arg, int child_bucket)
                      rv == AP_MPM_PODX_GRACEFUL ? ST_GRACEFUL : ST_UNGRACEFUL);
     }
 
+    if (terminate_mode == ST_GRACEFUL) {
+        while (apr_atomic_read32(&connection_count) > 0) {
+            apr_sleep(apr_time_from_msec(100));
+        }
+    }
+
     free(threads);
 
     clean_child_exit(resource_shortage ? APEXIT_CHILDSICK : 0);
@@ -2103,6 +2121,9 @@ static int worker_pre_config(apr_pool_t *pconf, apr_pool_t *plog,
     apr_status_t rv;
     const char *userdata_key = "mpm_worker_module";
 
+    APR_REGISTER_OPTIONAL_FN(ap_mpm_note_extra_connection_added);
+    APR_REGISTER_OPTIONAL_FN(ap_mpm_note_extra_connection_removed);
+
     debug = ap_exists_config_define("DEBUG");
 
     if (debug) {