diff options
| -rw-r--r-- | src/libstore/local-store.cc | 43 |
1 files changed, 37 insertions, 6 deletions
diff --git a/src/libstore/local-store.cc b/src/libstore/local-store.cc index 870644c88ba9..ac6d768a0825 100644 --- a/src/libstore/local-store.cc +++ b/src/libstore/local-store.cc @@ -65,6 +65,37 @@ SQLiteStmt::~SQLiteStmt() } +struct SQLiteTxn +{ + bool active; + sqlite3 * db; + + SQLiteTxn(sqlite3 * db) : active(false) { + this->db = db; + if (sqlite3_exec(db, "begin;", 0, 0, 0) != SQLITE_OK) + throw SQLiteError(db, "starting transaction"); + active = true; + } + + void commit() + { + if (sqlite3_exec(db, "commit;", 0, 0, 0) != SQLITE_OK) + throw SQLiteError(db, "committing transaction"); + active = false; + } + + ~SQLiteTxn() + { + try { + if (active && sqlite3_exec(db, "rollback;", 0, 0, 0) != SQLITE_OK) + throw SQLiteError(db, "aborting transaction"); + } catch (...) { + ignoreException(); + } + } +}; + + void checkStoreNotSymlink() { if (getEnv("NIX_IGNORE_SYMLINK_STORE") == "1") return; @@ -130,7 +161,8 @@ LocalStore::LocalStore() throw SQLiteError(db, "setting timeout"); /* Check the current database schema and if necessary do an - upgrade. */ + upgrade. !!! Race condition: several processes could start + the upgrade at the same time. */ int curSchema = getSchema(); if (curSchema > nixSchemaVersion) throw Error(format("current Nix store schema is version %1%, but I only support %2%") @@ -1264,9 +1296,8 @@ void LocalStore::upgradeStore6() PathSet validPaths = queryValidPaths(); - if (sqlite3_exec(db, "begin;", 0, 0, 0) != SQLITE_OK) - throw SQLiteError(db, "running `begin' command"); - + SQLiteTxn txn(db); + std::map<Path, sqlite3_int64> pathToId; foreach (PathSet::iterator, i, validPaths) { @@ -1319,8 +1350,8 @@ void LocalStore::upgradeStore6() std::cerr << "\n"; - if (sqlite3_exec(db, "commit;", 0, 0, 0) != SQLITE_OK) - throw SQLiteError(db, "running `commit' command"); + txn.commit(); + writeFile(schemaPath, (format("%1%") % nixSchemaVersion).str()); lockFile(globalLock, ltRead, true); |