Migrate user_version during cipher_migrate

developernotes · developernotes · commit 7d3f1c047697 · 2013-08-26T15:23:24.000-05:00
diff --git a/src/crypto_impl.c b/src/crypto_impl.c
@@ -889,6 +889,7 @@ int sqlcipher_codec_ctx_migrate(codec_ctx *ctx) {
   int upgrade_4k_format = 0;
   sqlite3 *test;
   char *err = 0;
+  int user_version = 0;
   static const unsigned char aCopy[] = {
     BTREE_SCHEMA_VERSION,     1,  /* Add one to the old schema cookie */
     BTREE_DEFAULT_CACHE_SIZE, 0,  /* Preserve the default page cache size */
@@ -905,15 +906,14 @@ int sqlcipher_codec_ctx_migrate(codec_ctx *ctx) {
     
     char *attach_command = sqlite3_mprintf("ATTACH DATABASE '%s-migrated' as migrate KEY '%s';",
                                             db_filename, key);
-
-    int rc = sqlcipher_check_connection(db_filename, key, key_sz, "");
+    int rc = sqlcipher_check_connection(db_filename, key, key_sz, "", &user_version);
     if(rc == SQLITE_OK){
       CODEC_TRACE(("No upgrade required - exiting\n"));
       goto exit;
     }
     
     // Version 2 - check for 4k with hmac format 
-    rc = sqlcipher_check_connection(db_filename, key, key_sz, pragma_4k_kdf_iter);
+    rc = sqlcipher_check_connection(db_filename, key, key_sz, pragma_4k_kdf_iter, &user_version);
     if(rc == SQLITE_OK) {
       CODEC_TRACE(("Version 2 format found\n"));
       upgrade_4k_format = 1;
@@ -922,7 +922,7 @@ int sqlcipher_codec_ctx_migrate(codec_ctx *ctx) {
     // Version 1 - check both no hmac and 4k together
     char *pragma_1x_and_4k = sqlite3_mprintf("%s%s", pragma_hmac_off,
                                              pragma_4k_kdf_iter);
-    rc = sqlcipher_check_connection(db_filename, key, key_sz, pragma_1x_and_4k);
+    rc = sqlcipher_check_connection(db_filename, key, key_sz, pragma_1x_and_4k, &user_version);
     sqlite3_free(pragma_1x_and_4k);
     if(rc == SQLITE_OK) {
       CODEC_TRACE(("Version 1 format found\n"));
@@ -935,11 +935,13 @@ int sqlcipher_codec_ctx_migrate(codec_ctx *ctx) {
       goto handle_error;
     }
 
+    char *set_user_version = sqlite3_mprintf("PRAGMA migrate.user_version = %d;", user_version);
     const char *commands[] = {
       upgrade_4k_format == 1 ? pragma_4k_kdf_iter : "",
       upgrade_1x_format == 1 ? pragma_hmac_off : "",
       attach_command,
       "SELECT sqlcipher_export('migrate');",
+      set_user_version,
     };
     for(command_idx = 0; command_idx < ArraySize(commands); command_idx++){
       const char *command = commands[command_idx];
@@ -952,6 +954,7 @@ int sqlcipher_codec_ctx_migrate(codec_ctx *ctx) {
       }
     }
     sqlite3_free(attach_command);
+    sqlite3_free(set_user_version);
     sqlcipher_free(key, key_sz);
     
     if(rc == SQLITE_OK){
@@ -1029,12 +1032,12 @@ int sqlcipher_codec_ctx_migrate(codec_ctx *ctx) {
   return rc;
 }
 
-int sqlcipher_check_connection(char *filename, char *key, int key_sz, char *sql) {
+int sqlcipher_check_connection(char *filename, char *key, int key_sz, char *sql, int *user_version) {
   int rc;
   sqlite3 *db;
   char *errMsg;
   sqlite3_stmt *statement;
-  char *query_sqlite_master = "SELECT count(*) FROM sqlite_master;";
+  char *query_user_version = "PRAGMA user_version;";
   
   rc = sqlite3_open(filename, &db);
   if(rc != SQLITE_OK){
@@ -1048,11 +1051,13 @@ int sqlcipher_check_connection(char *filename, char *key, int key_sz, char *sql)
   if(rc != SQLITE_OK){
     goto cleanup;
   }
-  rc = sqlite3_prepare(db, query_sqlite_master, -1, &statement, NULL);
+  rc = sqlite3_prepare(db, query_user_version, -1, &statement, NULL);
   if(rc != SQLITE_OK){
     goto cleanup;
   }
-  if(sqlite3_step(statement) == SQLITE_ROW){
+  rc = sqlite3_step(statement);
+  if(rc == SQLITE_ROW){
+    *user_version = sqlite3_column_int(statement, 0);
     rc = SQLITE_OK;
   }
   goto cleanup;
