PGPRO-2160: to_files may be uninitialized if from_backup has BACKUP_STATUS_DELETING

Author: za-arthur

src/merge.c

@@ -164,7 +164,7 @@ merge_backups(pgBackup *to_backup, pgBackup *from_backup)
 				control_file[MAXPGPATH];
 	parray	   *files,
 			   *to_files;
-	pthread_t  *threads;
+	pthread_t  *threads = NULL;
 	merge_files_arg *threads_args;
 	int			i;
 	bool		merge_isok = true;
@@ -193,19 +193,6 @@ merge_backups(pgBackup *to_backup, pgBackup *from_backup)
 	if (from_backup->status == BACKUP_STATUS_CORRUPT)
 		elog(ERROR, "Interrupt merging");
 
-	/*
-	 * Previous merging was interrupted during deleting source backup. It is
-	 * safe just to delete it again.
-	 */
-	if (from_backup->status == BACKUP_STATUS_DELETING)
-		goto delete_source_backup;
-
-	to_backup->status = BACKUP_STATUS_MERGING;
-	write_backup_status(to_backup);
-
-	from_backup->status = BACKUP_STATUS_MERGING;
-	write_backup_status(from_backup);
-
 	/*
 	 * Make backup paths.
 	 */
@@ -216,8 +203,6 @@ merge_backups(pgBackup *to_backup, pgBackup *from_backup)
 	pgBackupGetPath(from_backup, from_database_path, lengthof(from_database_path),
 					DATABASE_DIR);
 
-	create_data_directories(to_database_path, from_backup_path, false);
-
 	/*
 	 * Get list of files which will be modified or removed.
 	 */
@@ -238,6 +223,21 @@ merge_backups(pgBackup *to_backup, pgBackup *from_backup)
 	/* sort by size for load balancing */
 	parray_qsort(files, pgFileCompareSize);
 
+	/*
+	 * Previous merging was interrupted during deleting source backup. It is
+	 * safe just to delete it again.
+	 */
+	if (from_backup->status == BACKUP_STATUS_DELETING)
+		goto delete_source_backup;
+
+	to_backup->status = BACKUP_STATUS_MERGING;
+	write_backup_status(to_backup);
+
+	from_backup->status = BACKUP_STATUS_MERGING;
+	write_backup_status(from_backup);
+
+	create_data_directories(to_database_path, from_backup_path, false);
+
 	threads = (pthread_t *) palloc(sizeof(pthread_t) * num_threads);
 	threads_args = (merge_files_arg *) palloc(sizeof(merge_files_arg) * num_threads);
 
@@ -344,8 +344,11 @@ merge_backups(pgBackup *to_backup, pgBackup *from_backup)
 	write_backup(to_backup);
 
 	/* Cleanup */
-	pfree(threads_args);
-	pfree(threads);
+	if (threads)
+	{
+		pfree(threads_args);
+		pfree(threads);
+	}
 
 	parray_walk(to_files, pgFileFree);
 	parray_free(to_files);