Re-implement the SSL session cache abstraction using a vtable; first

step towards use of the ap_provider interface:

* modules/ssl/ssl_private.h (modssl_sesscache_provider): Add new
  vtable type.
  (SSLModConfigRec): Reference the vtable here.
  Replace all the ssl_scache_* prototypes with provider vtable objects.

* modules/ssl/ssl_scache.c (ssl_scache_init, ssl_scache_kill, 
  ssl_scache_retrieve, ssl_scache_store, ssl_scache_remove,
  ssl_ext_status_hook): Use callbacks from vtable rather than ifdef
  spaghetti.

* modules/ssl/ssl_engine_init.c (ssl_init_ctx_session_cache):
  Only install the OpenSSL callbacks if a vtable is configured.

* modules/ssl/ssl_engine_config.c (ssl_cmd_SSLSessionCache): Set up
  vtable pointer.

* modules/ssl/ssl_scache_dc.c, modules/ssl_scache_mc.c: Adjust to make
  implementations static, and add vtable definition.

* modules/ssl_scache_shmcb.c: Likewise; also move the init
  one-per-process requirement down here.

* modules/ssl_scache_dbm.c: Likewise; also (temporarily) use a local
  subpool in the store callback.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@630163 13f79535-47bb-0310-9956-ffa450edef68

8 files changed, 134 insertions, 160 deletions

diff --git a/modules/ssl/ssl_engine_config.c b/modules/ssl/ssl_engine_config.c
index 7cda7667f4..57bae4d248 100644
--- a/modules/ssl/ssl_engine_config.c
+++ b/modules/ssl/ssl_engine_config.c
@@ -63,7 +63,7 @@ SSLModConfigRec *ssl_config_global_create(server_rec *s)
     mc->nSessionCacheDataSize  = 0;
     mc->pSessionCacheDataMM    = NULL;
     mc->pSessionCacheDataRMM   = NULL;
-    mc->tSessionCacheDataTable = NULL;
+    mc->sesscache              = NULL;
     mc->nMutexMode             = SSL_MUTEXMODE_UNSET;
     mc->nMutexMech             = APR_LOCK_DEFAULT;
     mc->szMutexFile            = NULL;
@@ -977,6 +977,7 @@ const char *ssl_cmd_SSLSessionCache(cmd_parms *cmd,
     }
     else if ((arglen > 4) && strcEQn(arg, "dbm:", 4)) {
         mc->nSessionCacheMode      = SSL_SCMODE_DBM;
+        mc->sesscache = &modssl_sesscache_dbm;
         mc->szSessionCacheDataFile = ap_server_root_relative(mc->pPool, arg+4);
         if (!mc->szSessionCacheDataFile) {
             return apr_psprintf(cmd->pool,
@@ -991,6 +992,7 @@ const char *ssl_cmd_SSLSessionCache(cmd_parms *cmd,
         return MODSSL_NO_SHARED_MEMORY_ERROR;
 #endif
         mc->nSessionCacheMode      = SSL_SCMODE_SHMCB;
+        mc->sesscache = &modssl_sesscache_shmcb;
         colon = ap_strchr_c(arg, ':');
         mc->szSessionCacheDataFile =
             ap_server_root_relative(mc->pPool, colon+1);
@@ -1032,6 +1034,7 @@ const char *ssl_cmd_SSLSessionCache(cmd_parms *cmd,
     else if ((arglen > 3) && strcEQn(arg, "dc:", 3)) {
 #ifdef HAVE_DISTCACHE
         mc->nSessionCacheMode      = SSL_SCMODE_DC;
+        mc->sesscache = &modssl_sesscache_dc;
         mc->szSessionCacheDataFile = apr_pstrdup(mc->pPool, arg+3);
         if (!mc->szSessionCacheDataFile) {
             return apr_pstrcat(cmd->pool,
@@ -1045,6 +1048,7 @@ const char *ssl_cmd_SSLSessionCache(cmd_parms *cmd,
     else if ((arglen > 3) && strcEQn(arg, "memcache:", 9)) {
 #ifdef HAVE_SSL_CACHE_MEMCACHE
         mc->nSessionCacheMode      = SSL_SCMODE_MC;
+        mc->sesscache = &modssl_sesscache_mc;
         mc->szSessionCacheDataFile = apr_pstrdup(mc->pPool, arg+9);
         if (!mc->szSessionCacheDataFile) {
             return apr_pstrcat(cmd->pool,
diff --git a/modules/ssl/ssl_engine_init.c b/modules/ssl/ssl_engine_init.c
index 71a950d31a..39fe17a00a 100644
--- a/modules/ssl/ssl_engine_init.c
+++ b/modules/ssl/ssl_engine_init.c
@@ -492,9 +492,11 @@ static void ssl_init_ctx_session_cache(server_rec *s,
 
     SSL_CTX_set_session_cache_mode(ctx, cache_mode);
 
-    SSL_CTX_sess_set_new_cb(ctx,    ssl_callback_NewSessionCacheEntry);
-    SSL_CTX_sess_set_get_cb(ctx,    ssl_callback_GetSessionCacheEntry);
-    SSL_CTX_sess_set_remove_cb(ctx, ssl_callback_DelSessionCacheEntry);
+    if (mc->sesscache) {
+        SSL_CTX_sess_set_new_cb(ctx,    ssl_callback_NewSessionCacheEntry);
+        SSL_CTX_sess_set_get_cb(ctx,    ssl_callback_GetSessionCacheEntry);
+        SSL_CTX_sess_set_remove_cb(ctx, ssl_callback_DelSessionCacheEntry);
+    }
 }
 
 static void ssl_init_ctx_callbacks(server_rec *s,
diff --git a/modules/ssl/ssl_private.h b/modules/ssl/ssl_private.h
index eaac13e6ab..4647375044 100644
--- a/modules/ssl/ssl_private.h
+++ b/modules/ssl/ssl_private.h
@@ -364,6 +364,18 @@ typedef struct {
     int non_ssl_request;
 } SSLConnRec;
 
+/* Session cache provider vtable. */
+typedef struct {
+    void (*init)(server_rec *s, apr_pool_t *pool);
+    void (*destroy)(server_rec *s);
+    BOOL (*store)(server_rec *s, UCHAR *id, int idlen,
+                  time_t expiry, SSL_SESSION *session);
+    SSL_SESSION *(*retrieve)(server_rec *s, UCHAR *id, int idlen,
+                             apr_pool_t *pool);
+    void (*delete)(server_rec *s, UCHAR *id, int idlen, apr_pool_t *pool);
+    void (*status)(request_rec *r, int flags, apr_pool_t *pool);
+} modssl_sesscache_provider;
+
 typedef struct {
     pid_t           pid;
     apr_pool_t     *pPool;
@@ -374,6 +386,10 @@ typedef struct {
     apr_shm_t      *pSessionCacheDataMM;
     apr_rmm_t      *pSessionCacheDataRMM;
     void           *tSessionCacheDataTable;
+
+    /* The configured provider: */
+    const modssl_sesscache_provider *sesscache;
+
     ssl_mutexmode_t nMutexMode;
     apr_lockmech_e  nMutexMech;
     const char     *szMutexFile;
@@ -595,38 +611,15 @@ SSL_SESSION *ssl_scache_retrieve(server_rec *, UCHAR *, int, apr_pool_t *);
 void         ssl_scache_remove(server_rec *, UCHAR *, int,
                                apr_pool_t *);
 
-char        *ssl_scache_id2sz(UCHAR *, int);
-void         ssl_scache_dbm_init(server_rec *, apr_pool_t *);
-void         ssl_scache_dbm_kill(server_rec *);
-BOOL         ssl_scache_dbm_store(server_rec *, UCHAR *, int,
-                                  time_t, SSL_SESSION *, apr_pool_t *);
-SSL_SESSION *ssl_scache_dbm_retrieve(server_rec *, UCHAR *, int,
-                                     apr_pool_t *);
-void         ssl_scache_dbm_remove(server_rec *, UCHAR *, int,
-                                   apr_pool_t *);
-void         ssl_scache_dbm_status(request_rec *r, int flags, apr_pool_t *);
-
-void         ssl_scache_shmcb_init(server_rec *, apr_pool_t *);
-void         ssl_scache_shmcb_kill(server_rec *);
-BOOL         ssl_scache_shmcb_store(server_rec *, UCHAR *, int, time_t, SSL_SESSION *);
-SSL_SESSION *ssl_scache_shmcb_retrieve(server_rec *, UCHAR *, int);
-void         ssl_scache_shmcb_remove(server_rec *, UCHAR *, int);
-void         ssl_scache_shmcb_status(request_rec *r, int flags, apr_pool_t *pool);
-
-void         ssl_scache_dc_init(server_rec *, apr_pool_t *);
-void         ssl_scache_dc_kill(server_rec *);
-BOOL         ssl_scache_dc_store(server_rec *, UCHAR *, int, time_t, SSL_SESSION *);
-SSL_SESSION *ssl_scache_dc_retrieve(server_rec *, UCHAR *, int);
-void         ssl_scache_dc_remove(server_rec *, UCHAR *, int);
-void         ssl_scache_dc_status(request_rec *r, int flags, apr_pool_t *pool);
+const modssl_sesscache_provider modssl_sesscache_shmcb;
+const modssl_sesscache_provider modssl_sesscache_dbm;
+
+#ifdef HAVE_DISTCACHE
+const modssl_sesscache_provider modssl_sesscache_dc;
+#endif
 
 #ifdef HAVE_SSL_CACHE_MEMCACHE
-void         ssl_scache_mc_init(server_rec *, apr_pool_t *);
-void         ssl_scache_mc_kill(server_rec *);
-BOOL         ssl_scache_mc_store(server_rec *, UCHAR *, int, time_t, SSL_SESSION *);
-SSL_SESSION *ssl_scache_mc_retrieve(server_rec *, UCHAR *, int, apr_pool_t *);
-void         ssl_scache_mc_remove(server_rec *, UCHAR *, int);
-void         ssl_scache_mc_status(request_rec *r, int flags, apr_pool_t *pool);
+const modssl_sesscache_provider modssl_sesscache_mc;
 #endif
 
 /** Proxy Support */
diff --git a/modules/ssl/ssl_scache.c b/modules/ssl/ssl_scache.c
index c54a57d595..efabfe8af6 100644
--- a/modules/ssl/ssl_scache.c
+++ b/modules/ssl/ssl_scache.c
@@ -45,55 +45,21 @@ void ssl_scache_init(server_rec *s, apr_pool_t *p)
      * Warn the user that he should use the session cache.
      * But we can operate without it, of course.
      */
-    if (mc->nSessionCacheMode == SSL_SCMODE_UNSET) {
+    if (mc->sesscache == NULL) {
         ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s,
                      "Init: Session Cache is not configured "
                      "[hint: SSLSessionCache]");
-        mc->nSessionCacheMode = SSL_SCMODE_NONE;
         return;
     }
 
-    if (mc->nSessionCacheMode == SSL_SCMODE_DBM)
-        ssl_scache_dbm_init(s, p);
-#ifdef HAVE_DISTCACHE
-    else if (mc->nSessionCacheMode == SSL_SCMODE_DC)
-        ssl_scache_dc_init(s, p);
-#endif
-#ifdef HAVE_SSL_CACHE_MEMCACHE
-    else if (mc->nSessionCacheMode == SSL_SCMODE_MC)
-        ssl_scache_mc_init(s, p);
-#endif
-    else if (mc->nSessionCacheMode == SSL_SCMODE_SHMCB) {
-        void *data;
-        const char *userdata_key = "ssl_scache_init";
-
-        apr_pool_userdata_get(&data, userdata_key, s->process->pool);
-        if (!data) {
-            apr_pool_userdata_set((const void *)1, userdata_key,
-                                  apr_pool_cleanup_null, s->process->pool);
-            return;
-        }
-        ssl_scache_shmcb_init(s, p);
-    }
+    mc->sesscache->init(s, p);
 }
 
 void ssl_scache_kill(server_rec *s)
 {
     SSLModConfigRec *mc = myModConfig(s);
 
-    if (mc->nSessionCacheMode == SSL_SCMODE_DBM)
-        ssl_scache_dbm_kill(s);
-    else if (mc->nSessionCacheMode == SSL_SCMODE_SHMCB)
-        ssl_scache_shmcb_kill(s);
-#ifdef HAVE_DISTCACHE
-    else if (mc->nSessionCacheMode == SSL_SCMODE_DC)
-        ssl_scache_dc_kill(s);
-#endif
-#ifdef HAVE_SSL_CACHE_MEMCACHE
-    else if (mc->nSessionCacheMode == SSL_SCMODE_MC)
-        ssl_scache_mc_kill(s);
-#endif
-    return;
+    mc->sesscache->destroy(s);
 }
 
 BOOL ssl_scache_store(server_rec *s, UCHAR *id, int idlen,
@@ -101,42 +67,16 @@ BOOL ssl_scache_store(server_rec *s, UCHAR *id, int idlen,
                       apr_pool_t *p)
 {
     SSLModConfigRec *mc = myModConfig(s);
-    BOOL rv = FALSE;
-
-    if (mc->nSessionCacheMode == SSL_SCMODE_DBM)
-        rv = ssl_scache_dbm_store(s, id, idlen, expiry, sess, p);
-    else if (mc->nSessionCacheMode == SSL_SCMODE_SHMCB)
-        rv = ssl_scache_shmcb_store(s, id, idlen, expiry, sess);
-#ifdef HAVE_DISTCACHE
-    else if (mc->nSessionCacheMode == SSL_SCMODE_DC)
-        rv = ssl_scache_dc_store(s, id, idlen, expiry, sess);
-#endif
-#ifdef HAVE_SSL_CACHE_MEMCACHE
-    else if (mc->nSessionCacheMode == SSL_SCMODE_MC)
-        rv = ssl_scache_mc_store(s, id, idlen, expiry, sess);
-#endif
-    return rv;
+    
+    return mc->sesscache->store(s, id, idlen, expiry, sess);
 }
 
 SSL_SESSION *ssl_scache_retrieve(server_rec *s, UCHAR *id, int idlen,
                                  apr_pool_t *p)
 {
     SSLModConfigRec *mc = myModConfig(s);
-    SSL_SESSION *sess = NULL;
-
-    if (mc->nSessionCacheMode == SSL_SCMODE_DBM)
-        sess = ssl_scache_dbm_retrieve(s, id, idlen, p);
-    else if (mc->nSessionCacheMode == SSL_SCMODE_SHMCB)
-        sess = ssl_scache_shmcb_retrieve(s, id, idlen);
-#ifdef HAVE_DISTCACHE
-    else if (mc->nSessionCacheMode == SSL_SCMODE_DC)
-        sess = ssl_scache_dc_retrieve(s, id, idlen);
-#endif
-#ifdef HAVE_SSL_CACHE_MEMCACHE
-    else if (mc->nSessionCacheMode == SSL_SCMODE_MC)
-        sess = ssl_scache_mc_retrieve(s, id, idlen, p);
-#endif
-    return sess;
+
+    return mc->sesscache->retrieve(s, id, idlen, p);
 }
 
 void ssl_scache_remove(server_rec *s, UCHAR *id, int idlen,
@@ -144,18 +84,8 @@ void ssl_scache_remove(server_rec *s, UCHAR *id, int idlen,
 {
     SSLModConfigRec *mc = myModConfig(s);
 
-    if (mc->nSessionCacheMode == SSL_SCMODE_DBM)
-        ssl_scache_dbm_remove(s, id, idlen, p);
-    else if (mc->nSessionCacheMode == SSL_SCMODE_SHMCB)
-        ssl_scache_shmcb_remove(s, id, idlen);
-#ifdef HAVE_DISTCACHE
-    else if (mc->nSessionCacheMode == SSL_SCMODE_DC)
-        ssl_scache_dc_remove(s, id, idlen);
-#endif
-#ifdef HAVE_SSL_CACHE_MEMCACHE
-    else if (mc->nSessionCacheMode == SSL_SCMODE_MC)
-        ssl_scache_mc_remove(s, id, idlen);
-#endif
+    mc->sesscache->delete(s, id, idlen, p);
+
     return;
 }
 
@@ -166,9 +96,9 @@ void ssl_scache_remove(server_rec *s, UCHAR *id, int idlen,
 */
 static int ssl_ext_status_hook(request_rec *r, int flags)
 {
-    SSLSrvConfigRec *sc = mySrvConfig(r->server);
+    SSLModConfigRec *mc = myModConfig(r->server);
 
-    if (sc == NULL || flags & AP_STATUS_SHORT)
+    if (mc == NULL || flags & AP_STATUS_SHORT)
         return OK;
 
     ap_rputs("<hr>\n", r);
@@ -178,18 +108,7 @@ static int ssl_ext_status_hook(request_rec *r, int flags)
     ap_rputs("</td></tr>\n", r);
     ap_rputs("<tr><td bgcolor=\"#ffffff\">\n", r);
 
-    if (sc->mc->nSessionCacheMode == SSL_SCMODE_DBM)
-        ssl_scache_dbm_status(r, flags, r->pool);
-    else if (sc->mc->nSessionCacheMode == SSL_SCMODE_SHMCB)
-        ssl_scache_shmcb_status(r, flags, r->pool);
-#ifdef HAVE_DISTCACHE
-    else if (sc->mc->nSessionCacheMode == SSL_SCMODE_DC)
-        ssl_scache_dc_status(r, flags, r->pool);
-#endif
-#ifdef HAVE_SSL_CACHE_MEMCACHE
-    else if (sc->mc->nSessionCacheMode == SSL_SCMODE_MC)
-        ssl_scache_mc_status(r, flags, r->pool);
-#endif
+    mc->sesscache->status(r, flags, r->pool);
 
     ap_rputs("</td></tr>\n", r);
     ap_rputs("</table>\n", r);
diff --git a/modules/ssl/ssl_scache_dbm.c b/modules/ssl/ssl_scache_dbm.c
index dac480cf26..d84df07b34 100644
--- a/modules/ssl/ssl_scache_dbm.c
+++ b/modules/ssl/ssl_scache_dbm.c
@@ -28,7 +28,10 @@
 
 static void ssl_scache_dbm_expire(server_rec *s);
 
-void ssl_scache_dbm_init(server_rec *s, apr_pool_t *p)
+static void ssl_scache_dbm_remove(server_rec *s, UCHAR *id, int idlen,
+                                  apr_pool_t *p);
+
+static void ssl_scache_dbm_init(server_rec *s, apr_pool_t *p)
 {
     SSLModConfigRec *mc = myModConfig(s);
     apr_dbm_t *dbm;
@@ -82,7 +85,7 @@ void ssl_scache_dbm_init(server_rec *s, apr_pool_t *p)
     return;
 }
 
-void ssl_scache_dbm_kill(server_rec *s)
+static void ssl_scache_dbm_kill(server_rec *s)
 {
     SSLModConfigRec *mc = myModConfig(s);
     apr_pool_t *p;
@@ -102,9 +105,8 @@ void ssl_scache_dbm_kill(server_rec *s)
     return;
 }
 
-BOOL ssl_scache_dbm_store(server_rec *s, UCHAR *id, int idlen,
-                          time_t expiry, SSL_SESSION *sess,
-                          apr_pool_t *p)
+static BOOL ssl_scache_dbm_store(server_rec *s, UCHAR *id, int idlen,
+                                 time_t expiry, SSL_SESSION *sess)
 {
     SSLModConfigRec *mc = myModConfig(s);
     apr_dbm_t *dbm;
@@ -114,6 +116,11 @@ BOOL ssl_scache_dbm_store(server_rec *s, UCHAR *id, int idlen,
     int nData;
     UCHAR *ucp;
     apr_status_t rv;
+    apr_pool_t *p;
+
+    /* ### This is not in any way sane, a persistent pool which gets
+     * cleared each time is needed. */
+    apr_pool_create(&p, s->process->pool);
 
     /* streamline session data */
     if ((nData = i2d_SSL_SESSION(sess, NULL)) > sizeof(ucaData)) {
@@ -167,6 +174,7 @@ BOOL ssl_scache_dbm_store(server_rec *s, UCHAR *id, int idlen,
                      "(store)",
                      mc->szSessionCacheDataFile);
         ssl_mutex_off(s);
+        apr_pool_destroy(p);
         free(dbmval.dptr);
         return FALSE;
     }
@@ -176,11 +184,13 @@ BOOL ssl_scache_dbm_store(server_rec *s, UCHAR *id, int idlen,
                      mc->szSessionCacheDataFile);
         apr_dbm_close(dbm);
         ssl_mutex_off(s);
+        apr_pool_destroy(p);
         free(dbmval.dptr);
         return FALSE;
     }
     apr_dbm_close(dbm);
     ssl_mutex_off(s);
+    apr_pool_destroy(p);
 
     /* free temporary buffers */
     free(dbmval.dptr);
@@ -191,8 +201,8 @@ BOOL ssl_scache_dbm_store(server_rec *s, UCHAR *id, int idlen,
     return TRUE;
 }
 
-SSL_SESSION *ssl_scache_dbm_retrieve(server_rec *s, UCHAR *id, int idlen,
-                                     apr_pool_t *p)
+static SSL_SESSION *ssl_scache_dbm_retrieve(server_rec *s, UCHAR *id, int idlen,
+                                            apr_pool_t *p)
 {
     SSLModConfigRec *mc = myModConfig(s);
     apr_dbm_t *dbm;
@@ -267,8 +277,8 @@ SSL_SESSION *ssl_scache_dbm_retrieve(server_rec *s, UCHAR *id, int idlen,
     return sess;
 }
 
-void ssl_scache_dbm_remove(server_rec *s, UCHAR *id, int idlen,
-                           apr_pool_t *p)
+static void ssl_scache_dbm_remove(server_rec *s, UCHAR *id, int idlen,
+                                  apr_pool_t *p)
 {
     SSLModConfigRec *mc = myModConfig(s);
     apr_dbm_t *dbm;
@@ -416,7 +426,7 @@ static void ssl_scache_dbm_expire(server_rec *s)
     return;
 }
 
-void ssl_scache_dbm_status(request_rec *r, int flags, apr_pool_t *p)
+static void ssl_scache_dbm_status(request_rec *r, int flags, apr_pool_t *p)
 {
     SSLModConfigRec *mc = myModConfig(r->server);
     apr_dbm_t *dbm;
@@ -466,3 +476,11 @@ void ssl_scache_dbm_status(request_rec *r, int flags, apr_pool_t *p)
     return;
 }
 
+const modssl_sesscache_provider modssl_sesscache_dbm = {
+    ssl_scache_dbm_init,
+    ssl_scache_dbm_kill,
+    ssl_scache_dbm_store,
+    ssl_scache_dbm_retrieve,
+    ssl_scache_dbm_remove,
+    ssl_scache_dbm_status
+};
diff --git a/modules/ssl/ssl_scache_dc.c b/modules/ssl/ssl_scache_dc.c
index b03b0dea4e..4227a34d34 100644
--- a/modules/ssl/ssl_scache_dc.c
+++ b/modules/ssl/ssl_scache_dc.c
@@ -48,7 +48,7 @@
 **
 */
 
-void ssl_scache_dc_init(server_rec *s, apr_pool_t *p)
+static void ssl_scache_dc_init(server_rec *s, apr_pool_t *p)
 {
     DC_CTX *ctx;
     SSLModConfigRec *mc = myModConfig(s);
@@ -88,7 +88,7 @@ void ssl_scache_dc_init(server_rec *s, apr_pool_t *p)
     return;
 }
 
-void ssl_scache_dc_kill(server_rec *s)
+static void ssl_scache_dc_kill(server_rec *s)
 {
     SSLModConfigRec *mc = myModConfig(s);
 
@@ -97,8 +97,8 @@ void ssl_scache_dc_kill(server_rec *s)
     mc->tSessionCacheDataTable = NULL;
 }
 
-BOOL ssl_scache_dc_store(server_rec *s, UCHAR *id, int idlen,
-                           time_t timeout, SSL_SESSION * pSession)
+static BOOL ssl_scache_dc_store(server_rec *s, UCHAR *id, int idlen,
+                                time_t timeout, SSL_SESSION * pSession)
 {
     unsigned char der[SSL_SESSION_MAX_DER];
     int der_len;
@@ -122,7 +122,7 @@ BOOL ssl_scache_dc_store(server_rec *s, UCHAR *id, int idlen,
     return TRUE;
 }
 
-SSL_SESSION *ssl_scache_dc_retrieve(server_rec *s, UCHAR *id, int idlen)
+static SSL_SESSION *ssl_scache_dc_retrieve(server_rec *s, UCHAR *id, int idlen, apr_pool_t *p)
 {
     unsigned char der[SSL_SESSION_MAX_DER];
     unsigned int der_len;
@@ -150,7 +150,7 @@ SSL_SESSION *ssl_scache_dc_retrieve(server_rec *s, UCHAR *id, int idlen)
     return pSession;
 }
 
-void ssl_scache_dc_remove(server_rec *s, UCHAR *id, int idlen)
+static void ssl_scache_dc_remove(server_rec *s, UCHAR *id, int idlen, apr_pool_t *p)
 {
     SSLModConfigRec *mc = myModConfig(s);
     DC_CTX *ctx = mc->tSessionCacheDataTable;
@@ -163,7 +163,7 @@ void ssl_scache_dc_remove(server_rec *s, UCHAR *id, int idlen)
     }
 }
 
-void ssl_scache_dc_status(request_rec *r, int flags, apr_pool_t *pool)
+static void ssl_scache_dc_status(request_rec *r, int flags, apr_pool_t *pool)
 {
     SSLModConfigRec *mc = myModConfig(r->server);
 
@@ -173,5 +173,14 @@ void ssl_scache_dc_status(request_rec *r, int flags, apr_pool_t *pool)
                " target: <b>%s</b><br>", mc->szSessionCacheDataFile);
 }
 
+const modssl_sesscache_provider modssl_sesscache_dc = {
+    ssl_scache_dc_init,
+    ssl_scache_dc_kill,
+    ssl_scache_dc_store,
+    ssl_scache_dc_retrieve,
+    ssl_scache_dc_remove,
+    ssl_scache_dc_status
+};
+
 #endif
 
diff --git a/modules/ssl/ssl_scache_memcache.c b/modules/ssl/ssl_scache_memcache.c
index 62ceaa38c2..ca97a1f077 100644
--- a/modules/ssl/ssl_scache_memcache.c
+++ b/modules/ssl/ssl_scache_memcache.c
@@ -70,7 +70,7 @@ static apr_memcache_t *memctxt;
 #endif
 
 
-void ssl_scache_mc_init(server_rec *s, apr_pool_t *p)
+static void ssl_scache_mc_init(server_rec *s, apr_pool_t *p)
 {
     apr_status_t rv;
     int thread_limit = 0;
@@ -158,7 +158,7 @@ void ssl_scache_mc_init(server_rec *s, apr_pool_t *p)
     return;
 }
 
-void ssl_scache_mc_kill(server_rec *s)
+static void ssl_scache_mc_kill(server_rec *s)
 {
 
 }
@@ -181,8 +181,8 @@ static char *mc_session_id2sz(unsigned char *id, int idlen,
     return str;
 }
 
-BOOL ssl_scache_mc_store(server_rec *s, UCHAR *id, int idlen,
-                           time_t timeout, SSL_SESSION *pSession)
+static BOOL ssl_scache_mc_store(server_rec *s, UCHAR *id, int idlen,
+                                time_t timeout, SSL_SESSION *pSession)
 {
     char buf[MC_KEY_LEN];
     char *strkey = NULL;
@@ -221,13 +221,12 @@ BOOL ssl_scache_mc_store(server_rec *s, UCHAR *id, int idlen,
     return TRUE;
 }
 
-SSL_SESSION *ssl_scache_mc_retrieve(server_rec *s, UCHAR *id, int idlen,
-                                    apr_pool_t *p)
+static SSL_SESSION *ssl_scache_mc_retrieve(server_rec *s, UCHAR *id, int idlen,
+                                           apr_pool_t *p)
 {
     SSL_SESSION *pSession;
     MODSSL_D2I_SSL_SESSION_CONST unsigned char *pder;
     apr_size_t der_len;
-    SSLModConfigRec *mc = myModConfig(s);
     char buf[MC_KEY_LEN];
     char* strkey = NULL;
     apr_status_t rv;
@@ -275,7 +274,7 @@ SSL_SESSION *ssl_scache_mc_retrieve(server_rec *s, UCHAR *id, int idlen,
     return pSession;
 }
 
-void ssl_scache_mc_remove(server_rec *s, UCHAR *id, int idlen)
+static void ssl_scache_mc_remove(server_rec *s, UCHAR *id, int idlen, apr_pool_t *p)
 {
     char buf[MC_KEY_LEN];
     char* strkey = NULL;
@@ -297,10 +296,18 @@ void ssl_scache_mc_remove(server_rec *s, UCHAR *id, int idlen)
     }
 }
 
-void ssl_scache_mc_status(request_rec *r, int flags, apr_pool_t *pool)
+static void ssl_scache_mc_status(request_rec *r, int flags, apr_pool_t *pool)
 {
     /* SSLModConfigRec *mc = myModConfig(r->server); */
     /* TODO: Make a mod_status handler. meh. */
 }
 
+const modssl_sesscache_provider modssl_sesscache_mc = {
+    ssl_scache_mc_init,
+    ssl_scache_mc_kill,
+    ssl_scache_mc_store,
+    ssl_scache_mc_retrieve,
+    ssl_scache_mc_remove,
+    ssl_scache_mc_status
+};
 #endif
diff --git a/modules/ssl/ssl_scache_shmcb.c b/modules/ssl/ssl_scache_shmcb.c
index 8e3e138cde..05235fbde8 100644
--- a/modules/ssl/ssl_scache_shmcb.c
+++ b/modules/ssl/ssl_scache_shmcb.c
@@ -173,7 +173,7 @@ static BOOL shmcb_subcache_remove(server_rec *, SHMCBHeader *, SHMCBSubcache *,
  * subcache internals are deferred to shmcb_subcache_*** functions lower down
  */
 
-void ssl_scache_shmcb_init(server_rec *s, apr_pool_t *p)
+static void ssl_scache_shmcb_init(server_rec *s, apr_pool_t *p)
 {
     SSLModConfigRec *mc = myModConfig(s);
     void *shm_segment;
@@ -182,6 +182,18 @@ void ssl_scache_shmcb_init(server_rec *s, apr_pool_t *p)
     SHMCBHeader *header;
     unsigned int num_subcache, num_idx, loop;
 
+    {
+        void *data;
+        const char *userdata_key = "ssl_scache_init";
+
+        apr_pool_userdata_get(&data, userdata_key, s->process->pool);
+        if (!data) {
+            apr_pool_userdata_set((const void *)1, userdata_key,
+                                  apr_pool_cleanup_null, s->process->pool);
+            return;
+        }
+    }
+
     /* Create shared memory segment */
     if (mc->szSessionCacheDataFile == NULL) {
         ap_log_error(APLOG_MARK, APLOG_ERR, 0, s,
@@ -296,7 +308,7 @@ void ssl_scache_shmcb_init(server_rec *s, apr_pool_t *p)
     mc->tSessionCacheDataTable = shm_segment;
 }
 
-void ssl_scache_shmcb_kill(server_rec *s)
+static void ssl_scache_shmcb_kill(server_rec *s)
 {
     SSLModConfigRec *mc = myModConfig(s);
 
@@ -307,8 +319,8 @@ void ssl_scache_shmcb_kill(server_rec *s)
     return;
 }
 
-BOOL ssl_scache_shmcb_store(server_rec *s, UCHAR *id, int idlen,
-                           time_t timeout, SSL_SESSION * pSession)
+static BOOL ssl_scache_shmcb_store(server_rec *s, UCHAR *id, int idlen,
+                                   time_t timeout, SSL_SESSION * pSession)
 {
     SSLModConfigRec *mc = myModConfig(s);
     BOOL to_return = FALSE;
@@ -351,7 +363,8 @@ done:
     return to_return;
 }
 
-SSL_SESSION *ssl_scache_shmcb_retrieve(server_rec *s, UCHAR *id, int idlen)
+static SSL_SESSION *ssl_scache_shmcb_retrieve(server_rec *s, UCHAR *id, int idlen,
+                                              apr_pool_t *p)
 {
     SSLModConfigRec *mc = myModConfig(s);
     SSL_SESSION *pSession = NULL;
@@ -381,7 +394,7 @@ done:
     return pSession;
 }
 
-void ssl_scache_shmcb_remove(server_rec *s, UCHAR *id, int idlen)
+static void ssl_scache_shmcb_remove(server_rec *s, UCHAR *id, int idlen, apr_pool_t *p)
 {
     SSLModConfigRec *mc = myModConfig(s);
     SHMCBHeader *header = mc->tSessionCacheDataTable;
@@ -406,7 +419,7 @@ done:
     ssl_mutex_off(s);
 }
 
-void ssl_scache_shmcb_status(request_rec *r, int flags, apr_pool_t *p)
+static void ssl_scache_shmcb_status(request_rec *r, int flags, apr_pool_t *p)
 {
     server_rec *s = r->server;
     SSLModConfigRec *mc = myModConfig(s);
@@ -736,3 +749,12 @@ static BOOL shmcb_subcache_remove(server_rec *s, SHMCBHeader *header,
 
     return to_return;
 }
+
+const modssl_sesscache_provider modssl_sesscache_shmcb = {
+    ssl_scache_shmcb_init,
+    ssl_scache_shmcb_kill,
+    ssl_scache_shmcb_store,
+    ssl_scache_shmcb_retrieve,
+    ssl_scache_shmcb_remove,
+    ssl_scache_shmcb_status
+};