ITS#3607 more enhancements

  - recovers correctly, logs status
  - for Quick mode, where no transactional environment exists, refuses to
     start if the database is inconsistent
  - warns of poor performance if DB_CONFIG is not present
  - detects changes to DB_CONFIG and forces a recovery

servers/slapd/back-bdb/init.c

@@ -20,7 +20,8 @@
 #include <ac/string.h>
 #include <ac/unistd.h>
 #include <ac/stdlib.h>
-
+#include <ac/errno.h>
+#include <sys/stat.h>
 #include "back-bdb.h"
 #include <lutil.h>
 #include <ldap_rq.h>
@@ -89,15 +90,176 @@ bdb_checkpoint( void *ctx, void *arg )
 	return NULL;
 }
 
+/*
+ * Unconditionally perform a database recovery. Only works on
+ * databases that were previously opened with transactions and
+ * logs enabled.
+ */
+static int
+bdb_do_recovery( BackendDB *be )
+{
+	struct bdb_info *bdb = (struct bdb_info *) be->be_private;
+	DB_ENV  *re_dbenv;
+	u_int32_t flags;
+	int		rc;
+	char	path[MAXPATHLEN], *ptr;
+
+	/* Create and init the recovery environment */
+	rc = db_env_create( &re_dbenv, 0 );
+	if( rc != 0 ) {
+		Debug( LDAP_DEBUG_ANY,
+			"bdb_do_recovery: db_env_create failed: %s (%d)\n",
+			db_strerror(rc), rc, 0 );
+		return rc;
+	}
+	re_dbenv->set_errpfx( re_dbenv, be->be_suffix[0].bv_val );
+	re_dbenv->set_errcall( re_dbenv, bdb_errcall );
+	(void)re_dbenv->set_verbose(re_dbenv, DB_VERB_RECOVERY, 1);
+	(void)re_dbenv->set_verbose(re_dbenv, DB_VERB_CHKPOINT, 1);
+
+	flags = DB_CREATE | DB_INIT_LOCK | DB_INIT_LOG | DB_INIT_MPOOL |
+		DB_INIT_TXN | DB_USE_ENVIRON | DB_RECOVER;
+
+	/* Open the environment, which will also perform the recovery */
+#ifdef HAVE_EBCDIC
+	strcpy( path, bdb->bi_dbenv_home );
+	__atoe( path );
+	rc = re_dbenv->open( re_dbenv,
+		path,
+		flags,
+		bdb->bi_dbenv_mode );
+#else
+	rc = re_dbenv->open( re_dbenv,
+		bdb->bi_dbenv_home,
+		flags,
+		bdb->bi_dbenv_mode );
+#endif
+	if( rc != 0 ) {
+		Debug( LDAP_DEBUG_ANY,
+			"bdb_do_recovery: dbenv_open failed: %s (%d)\n",
+			db_strerror(rc), rc, 0 );
+		return rc;
+	}
+	(void) re_dbenv->close( re_dbenv, 0 );
+
+	/* By convention we reset the mtime for id2entry.bdb to the current time */
+	ptr = lutil_strcopy( path, bdb->bi_dbenv_home);
+	*ptr++ = LDAP_DIRSEP[0];
+	strcpy( ptr, bdbi_databases[0].file);
+	(void) utime( path, NULL);
+
+	return 0;
+}
+
+/*
+ * Database recovery logic:
+ * This function is called whenever the database appears to have been
+ * shut down uncleanly, as determined by the alock functions. 
+ * Because of the -q function in slapadd, there is also the possibility
+ * that the shutdown happened when transactions weren't being used and
+ * the database is likely to be corrupt. The function checks for this
+ * condition by examining the environment to make sure it had previously
+ * been opened with transactions enabled. If this is the case, the
+ * database is recovered as usual. If transactions were not enabled,
+ * then this function will return a fail.
+ */
+static int
+bdb_db_recover( BackendDB *be )
+{
+	struct bdb_info *bdb = (struct bdb_info *) be->be_private;
+	DB_ENV  *re_dbenv;
+	u_int32_t flags;
+	int		rc;
+#ifdef HAVE_EBCDIC
+	char	path[MAXPATHLEN];
+#endif
+
+	/* Create the recovery environment, then open it.
+	 * We use the DB_JOIN in combination with a flags value of
+	 * zero so we join an existing environment and can read the
+	 * value of the flags that were used the last time the 
+	 * environment was opened. DB_CREATE is added because the
+	 * open would fail if the only thing that had been done
+	 * was an open with transactions and logs disabled.
+	 */
+	rc = db_env_create( &re_dbenv, 0 );
+	if( rc != 0 ) {
+		Debug( LDAP_DEBUG_ANY,
+			"bdb_db_recover: db_env_create failed: %s (%d)\n",
+			db_strerror(rc), rc, 0 );
+		return rc;
+	}
+	re_dbenv->set_errpfx( re_dbenv, be->be_suffix[0].bv_val );
+	re_dbenv->set_errcall( re_dbenv, bdb_errcall );
+
+	Debug( LDAP_DEBUG_TRACE,
+		"bdb_db_recover: dbenv_open(%s)\n",
+		bdb->bi_dbenv_home, 0, 0);
+
+#ifdef HAVE_EBCDIC
+	strcpy( path, bdb->bi_dbenv_home );
+	__atoe( path );
+	rc = re_dbenv->open( re_dbenv,
+		path,
+		DB_JOINENV,
+		bdb->bi_dbenv_mode );
+#else
+	rc = re_dbenv->open( re_dbenv,
+		bdb->bi_dbenv_home,
+		DB_JOINENV,
+		bdb->bi_dbenv_mode );
+#endif
+
+	if( rc == ENOENT ) {
+		goto re_exit;
+	}
+	else if( rc != 0 ) {
+		Debug( LDAP_DEBUG_ANY,
+			"bdb_db_recover: dbenv_open failed: %s (%d)\n",
+			db_strerror(rc), rc, 0 );
+		return rc;
+	}
+
+	/*
+	 * Check the flags that had been used in the previous open.
+	 * The environment needed to have had both
+	 * DB_INIT_LOG and DB_INIT_TXN set for us to be willing to
+	 * recover the database. Otherwise the an app failed while running
+	 * without transactions and logs enabled and the dn2id and id2entry
+	 * mapping is likely to be corrupt.
+	 */
+	rc = re_dbenv->get_open_flags( re_dbenv, &flags );
+	if( rc != 0 ) {
+		Debug( LDAP_DEBUG_ANY,
+			"bdb_db_recover: get_open_flags failed: %s (%d)\n",
+			db_strerror(rc), rc, 0 );
+		return rc;
+	}
+
+	(void) re_dbenv->close( re_dbenv, 0 );
+
+	if( (flags & DB_INIT_LOG) && (flags & DB_INIT_TXN) ) {
+		return bdb_do_recovery( be );
+	}
+
+re_exit:
+	Debug( LDAP_DEBUG_ANY,
+		"bdb_db_recover: Database cannot be recovered. "\
+		"Restore from backup!\n", 0, 0, 0);
+	return -1;
+
+}
+
+
 static int
 bdb_db_open( BackendDB *be )
 {
 	int rc, i;
 	struct bdb_info *bdb = (struct bdb_info *) be->be_private;
+	struct stat stat1, stat2;
 	u_int32_t flags;
-#ifdef HAVE_EBCDIC
 	char path[MAXPATHLEN];
-#endif
+	char *ptr;
 
 	Debug( LDAP_DEBUG_ARGS,
 		"bdb_db_open: %s\n",
@@ -110,36 +272,97 @@ bdb_db_open( BackendDB *be )
 		return -1;
 	}
 #endif
-	/* we should check existance of dbenv_home and db_directory */
 
-	rc = db_env_create( &bdb->bi_dbenv, 0 );
-	if( rc != 0 ) {
+	/* Check existence of dbenv_home. Any error means trouble */
+	rc = stat( bdb->bi_dbenv_home, &stat1 );
+	if( rc !=0 ) {
 		Debug( LDAP_DEBUG_ANY,
-			"bdb_db_open: db_env_create failed: %s (%d)\n",
-			db_strerror(rc), rc, 0 );
-		return rc;
+			"bdb_db_open: Cannot access database directory %s (%d)\n",
+			bdb->bi_dbenv_home, errno, 0 );
+			return -1;
 	}
-
-	flags = DB_INIT_MPOOL | DB_THREAD | DB_CREATE;
-
-	if ( !( slapMode & SLAP_TOOL_QUICK ))
-		flags |= DB_INIT_LOCK | DB_INIT_LOG | DB_INIT_TXN;
 	
-	rc = alock_open( &bdb->bi_alock_info, "slapd", bdb->bi_dbenv_home,
-		slapMode & SLAP_TOOL_READONLY ?  ALOCK_LOCKED : ALOCK_UNIQUE );
+	/* Perform database use arbitration/recovery logic */
+	rc = alock_open( &bdb->bi_alock_info, 
+				"slapd", 
+				bdb->bi_dbenv_home,
+				slapMode & SLAP_TOOL_READONLY ?
+				ALOCK_LOCKED : ALOCK_UNIQUE );
+
 	if( rc == ALOCK_RECOVER ) {
 		Debug( LDAP_DEBUG_ANY,
-			"bdb_db_open: alock_open: recovery required\n", 0, 0, 0 );
-		flags |= DB_RECOVER;
+			"bdb_db_open: unclean shutdown detected;"
+			" attempting recovery.\n", 
+			0, 0, 0 );
+		if( bdb_db_recover( be ) != 0 ) {
+			Debug( LDAP_DEBUG_ANY,
+				"bdb_db_open: DB recovery failed.\n",
+				0, 0, 0 );
+			return -1;
+		}
+		if( alock_recover (&bdb->bi_alock_info) != 0 ) {
+			Debug( LDAP_DEBUG_ANY,
+				"bdb_db_open: alock_recover failed\n",
+				0, 0, 0 );
+			return -1;
+		}
+
 	} else if( rc == ALOCK_BUSY ) {
 		Debug( LDAP_DEBUG_ANY,
-		   "bdb_db_open: alock_open: database in use\n", 0, 0, 0 );
+			"bdb_db_open: database already in use\n", 
+			0, 0, 0 );
 		return -1;
 	} else if( rc != ALOCK_CLEAN ) {
 		Debug( LDAP_DEBUG_ANY,
-		   "bdb_db_open: alock_open: database unstable\n", 0, 0, 0 );
+			"bdb_db_open: alock package is unstable\n", 
+			0, 0, 0 );
 		return -1;
 	}
+	
+	/*
+	 * The DB_CONFIG file may have changed. If so, recover the
+	 * database so that new settings are put into effect. Also
+	 * note the possible absence of DB_CONFIG in the log.
+	 */
+	if( stat( bdb->bi_db_config_path, &stat1 ) == 0 ) {
+		ptr = lutil_strcopy(path, bdb->bi_dbenv_home);
+		*ptr++ = LDAP_DIRSEP[0];
+		strcpy( ptr, bdbi_databases[0].file);
+		if( stat( path, &stat2 ) == 0 ) {
+			if( stat2.st_mtime <= stat1.st_mtime ) {
+				Debug( LDAP_DEBUG_ANY,
+					"bdb_db_open: DB_CONFIG for suffix %s has changed.\n"
+					"Performing database recovery to activate new settings.\n",
+					be->be_suffix[0].bv_val, 0, 0 );
+				if( bdb_do_recovery( be ) != 0) {
+					Debug( LDAP_DEBUG_ANY,
+						"bdb_db_open: db recovery failed.\n",
+						0, 0, 0 );
+					return -1;
+				}
+			}
+					
+		}
+	}
+	else {
+		Debug( LDAP_DEBUG_ANY,
+			"bdb_db_open: Warning - No DB_CONFIG file found "
+			"in directory %s: (%d)\n"
+			"Expect poor performance for suffix %s.\n",
+			bdb->bi_dbenv_home, errno, be->be_suffix[0].bv_val );
+	}
+		
+	flags = DB_INIT_MPOOL | DB_THREAD | DB_CREATE;
+	if ( !( slapMode & SLAP_TOOL_QUICK ))
+		flags |= DB_INIT_LOCK | DB_INIT_LOG | DB_INIT_TXN;
+
+	rc = db_env_create( &bdb->bi_dbenv, 0 );
+	if( rc != 0 ) {
+		Debug( LDAP_DEBUG_ANY,
+			"bdb_db_open: db_env_create failed: %s (%d)\n",
+			db_strerror(rc), rc, 0 );
+		return rc;
+	}
 
 	/* If a key was set, use shared memory for the BDB environment */
 	if ( bdb->bi_shm_key ) {
@@ -205,14 +428,6 @@ bdb_db_open( BackendDB *be )
 			db_strerror(rc), rc, 0 );
 		return rc;
 	}
-	if( flags & DB_RECOVER ) {
-		rc = alock_recover (&bdb->bi_alock_info);
-		if( rc != 0 ) {
-			Debug( LDAP_DEBUG_ANY,
-			   "bdb_db_open: unable to alock_recover\n", 0, 0, 0 );
-			return -1;
-		}
-	}
 
 	flags = DB_THREAD | bdb->bi_db_opflags;
 
@@ -398,7 +613,7 @@ bdb_db_close( BackendDB *be )
 		ldap_pvt_thread_rdwr_wunlock ( &bdb->bi_idl_tree_rwlock );
 	}
 
-	if ( !( slapMode & SLAP_TOOL_QUICK )) {
+	if ( !( slapMode & SLAP_TOOL_QUICK ) && bdb->bi_dbenv ) {
 		XLOCK_ID_FREE(bdb->bi_dbenv, bdb->bi_cache.c_locker);
 	}