ITS#8486 Protect tavl_* calls in play_sessionlog

diff --git a/servers/slapd/overlays/syncprov.c b/servers/slapd/overlays/syncprov.c
index f222ca4f774924b68cc2f7e8a465d8c8d40bf447..ba6e4a6a5019d4e8a915586a2e41a0d4c87b578a 100644 (file)
--- a/servers/slapd/overlays/syncprov.c
+++ b/servers/slapd/overlays/syncprov.c
@@ -132,7 +132,7 @@ typedef struct sessionlog {
        int             sl_size;
        int             sl_playing;
        TAvlnode *sl_entries;
-       ldap_pvt_thread_mutex_t sl_mutex;
+       ldap_pvt_thread_rdwr_t sl_mutex;
 } sessionlog;
 
 /* Accesslog callback data */
@@ -1651,14 +1651,14 @@ syncprov_add_slog( Operation *op )
                         * state with respect to such operations, so we ignore them and
                         * wipe out anything in the log if we see them.
                         */
-                       ldap_pvt_thread_mutex_lock( &sl->sl_mutex );
+                       ldap_pvt_thread_rdwr_wlock( &sl->sl_mutex );
                        /* can only do this if no one else is reading the log at the moment */
                        if ( !sl->sl_playing ) {
                                tavl_free( sl->sl_entries, (AVL_FREE)ch_free );
                                sl->sl_num = 0;
                                sl->sl_entries = NULL;
                        }
-                       ldap_pvt_thread_mutex_unlock( &sl->sl_mutex );
+                       ldap_pvt_thread_rdwr_wunlock( &sl->sl_mutex );
                        return;
                }
 
@@ -1677,7 +1677,7 @@ syncprov_add_slog( Operation *op )
                se->se_csn.bv_len = op->o_csn.bv_len;
                se->se_sid = slap_parse_csn_sid( &se->se_csn );
 
-               ldap_pvt_thread_mutex_lock( &sl->sl_mutex );
+               ldap_pvt_thread_rdwr_wlock( &sl->sl_mutex );
                if ( LogTest( LDAP_DEBUG_SYNC ) ) {
                        char uuidstr[40] = {};
                        if ( !BER_BVISEMPTY( &opc->suuid ) ) {
@@ -1732,7 +1732,7 @@ syncprov_add_slog( Operation *op )
                                sl->sl_num--;
                        }
                }
-               ldap_pvt_thread_mutex_unlock( &sl->sl_mutex );
+               ldap_pvt_thread_rdwr_wunlock( &sl->sl_mutex );
        }
 }
 
@@ -1968,12 +1968,12 @@ syncprov_play_sessionlog( Operation *op, SlapReply *rs, sync_control *srs,
        char cbuf[LDAP_PVT_CSNSTR_BUFSIZE];
        struct berval delcsn[2];
 
-       ldap_pvt_thread_mutex_lock( &sl->sl_mutex );
+       ldap_pvt_thread_rdwr_wlock( &sl->sl_mutex );
        /* Are there any log entries, and is the consumer state
         * present in the session log?
         */
        if ( !sl->sl_num ) {
-               ldap_pvt_thread_mutex_unlock( &sl->sl_mutex );
+               ldap_pvt_thread_rdwr_wunlock( &sl->sl_mutex );
                return rc;
        }
        assert( sl->sl_num > 0 );
@@ -1997,7 +1997,7 @@ syncprov_play_sessionlog( Operation *op, SlapReply *rs, sync_control *srs,
                do_play = 1;
 
        if ( !do_play ) {
-               ldap_pvt_thread_mutex_unlock( &sl->sl_mutex );
+               ldap_pvt_thread_rdwr_wunlock( &sl->sl_mutex );
                return rc;
        }
 
@@ -2005,7 +2005,7 @@ syncprov_play_sessionlog( Operation *op, SlapReply *rs, sync_control *srs,
        i = 0;
        nmods = 0;
        sl->sl_playing++;
-       ldap_pvt_thread_mutex_unlock( &sl->sl_mutex );
+       ldap_pvt_thread_rdwr_wunlock( &sl->sl_mutex );
 
        uuids = op->o_tmpalloc( (num) * sizeof( struct berval ) +
                        num * UUID_LEN, op->o_tmpmemctx );
@@ -2014,9 +2014,10 @@ syncprov_play_sessionlog( Operation *op, SlapReply *rs, sync_control *srs,
                        num * LDAP_PVT_CSNSTR_BUFSIZE, op->o_tmpmemctx );
        csns[0].bv_val = (char *)(csns + num);
 
+       ldap_pvt_thread_rdwr_rlock( &sl->sl_mutex );
        /* Make a copy of the relevant UUIDs. Put the Deletes up front
         * and everything else at the end. Do this first so we can
-        * unlock the list mutex.
+        * let the write side manage the sessionlog again.
         */
        assert( sl->sl_entries );
 
@@ -2037,6 +2038,8 @@ syncprov_play_sessionlog( Operation *op, SlapReply *rs, sync_control *srs,
                slog_entry *se = entry->avl_data;
                int k;
 
+               /* Make sure writes can still make progress */
+               ldap_pvt_thread_rdwr_runlock( &sl->sl_mutex );
                ndel = 1;
                for ( k=0; k<srs->sr_state.numcsns; k++ ) {
                        if ( se->se_sid == srs->sr_state.sids[k] ) {
@@ -2045,6 +2048,7 @@ syncprov_play_sessionlog( Operation *op, SlapReply *rs, sync_control *srs,
                        }
                }
                if ( ndel <= 0 ) {
+                       ldap_pvt_thread_rdwr_rlock( &sl->sl_mutex );
                        continue;
                }
                ndel = 0;
@@ -2058,14 +2062,17 @@ syncprov_play_sessionlog( Operation *op, SlapReply *rs, sync_control *srs,
                        Debug( LDAP_DEBUG_SYNC, "%s syncprov_play_sessionlog: "
                                "cmp %d, csn %s too new, we're finished\n",
                                op->o_log_prefix, ndel, se->se_csn.bv_val );
+                       ldap_pvt_thread_rdwr_rlock( &sl->sl_mutex );
                        break;
                }
                if ( se->se_tag == LDAP_REQ_DELETE ) {
                        j = i;
                        i++;
                } else {
-                       if ( se->se_tag == LDAP_REQ_ADD )
+                       if ( se->se_tag == LDAP_REQ_ADD ) {
+                               ldap_pvt_thread_rdwr_rlock( &sl->sl_mutex );
                                continue;
+                       }
                        nmods++;
                        j = num - nmods;
                }
@@ -2087,10 +2094,12 @@ syncprov_play_sessionlog( Operation *op, SlapReply *rs, sync_control *srs,
                                op->o_log_prefix, se->se_tag == LDAP_REQ_DELETE ? "deleted" : "modified",
                                uuidstr, csns[j].bv_val );
                }
+               ldap_pvt_thread_rdwr_rlock( &sl->sl_mutex );
        } while ( (entry = tavl_next( entry, TAVL_DIR_RIGHT )) != NULL );
-       ldap_pvt_thread_mutex_lock( &sl->sl_mutex );
+       ldap_pvt_thread_rdwr_runlock( &sl->sl_mutex );
+       ldap_pvt_thread_rdwr_wlock( &sl->sl_mutex );
        sl->sl_playing--;
-       ldap_pvt_thread_mutex_unlock( &sl->sl_mutex );
+       ldap_pvt_thread_rdwr_wunlock( &sl->sl_mutex );
 
        ndel = i;
 
@@ -3670,7 +3679,7 @@ sp_cf_gen(ConfigArgs *c)
                if ( !sl ) {
                        if ( !size ) break;
                        sl = ch_calloc( 1, sizeof( sessionlog ));
-                       ldap_pvt_thread_mutex_init( &sl->sl_mutex );
+                       ldap_pvt_thread_rdwr_init( &sl->sl_mutex );
                        si->si_logs = sl;
                }
                sl->sl_size = size;
@@ -4016,7 +4025,7 @@ syncprov_db_destroy(
                        if ( sl->sl_sids )
                                ch_free( sl->sl_sids );
 
-                       ldap_pvt_thread_mutex_destroy(&si->si_logs->sl_mutex);
+                       ldap_pvt_thread_rdwr_destroy(&si->si_logs->sl_mutex);
                        ch_free( si->si_logs );
                }
                if ( si->si_ctxcsn )