Support running an SQL file on init

staticlibs · staticlibs · commit b809a7528280 · 2025-06-06T17:56:37.000+01:00
This change adds support for `session_init_sql_file` connection option,
that allows to speficy the path to an SQL file in local file system,
that will be read by the driver and executed in a newly created
connection before passing it to user.

By default the file is initalized only once per database, on the first
connection established to this DB.

For `:memory:` connection-private DBs it effectively executed once per
connection.

In addition to the DB init, it supports executing a part of the SQL
file for every connection. It looks for the specific marker:

```
/* DUCKDB_CONNECTION_INIT_BELOW_MARKER */
```

in the SQL file. If this marker is present - everything before the
marker is executed on DB init, and everything after this marker - on
connection init.

DB init is not re-run when the DB is closed and re-opened after the last
connection to it was closed and then new one created. If such re-init is
necessary - `jdbc_pin_db` option is supposed to be used instead.

It is understood, that this feature can be security sensitive (it
effectively implements an RCE entry) in contexts, where other
applications/processes/users can control the appending to user-specified
connection string or re-writing the specified file in local file system.
The following security measures are taken to mitigate that:

 - `session_init_sql_file` option can only be specified in the
   connection string itself, it is not accepted as part of connection
   `Properties`
 - `session_init_sql_file` option must be specified as the first option
   in the connection string, for example:
   'jdbc:duckdb:;session_init_sql_file=/path/to/init.sql'
 - `session_init_sql_file_sha256=&lt;sha56sum_of_sql_file&gt;` option can be
   specified, the file contents SHA-256 sum is checked againts this
   value
 - `session_init_sql_file_sha256` option can only be specified in the
   connection string itself
 - `session_init_sql_file` and `session_init_sql_file_sha256` options
   cannot be specified multiple times
 - content of the SQL file are available to the running code using
   `DuckDBConnection#getSessionInitSQL()` method

Testing: new tests added in a separate file.
diff --git a/src/main/java/org/duckdb/DuckDBConnection.java b/src/main/java/org/duckdb/DuckDBConnection.java
@@ -45,25 +45,31 @@ public final class DuckDBConnection implements java.sql.Connection {
     volatile boolean transactionRunning;
     final String url;
     private final boolean readOnly;
+    private final String sessionInitSQL;
 
-    public static DuckDBConnection newConnection(String url, boolean readOnly, Properties properties)
-        throws SQLException {
+    public static DuckDBConnection newConnection(String url, boolean readOnly, Properties properties) throws Exception {
+        return newConnection(url, readOnly, null, properties);
+    }
+
+    public static DuckDBConnection newConnection(String url, boolean readOnly, String sessionInitSQL,
+                                                 Properties properties) throws SQLException {
         if (null == properties) {
             properties = new Properties();
         }
         String dbName = dbNameFromUrl(url);
         String autoCommitStr = removeOption(properties, JDBC_AUTO_COMMIT);
         boolean autoCommit = isStringTruish(autoCommitStr, true);
         ByteBuffer nativeReference = DuckDBNative.duckdb_jdbc_startup(dbName.getBytes(UTF_8), readOnly, properties);
-        return new DuckDBConnection(nativeReference, url, readOnly, autoCommit);
+        return new DuckDBConnection(nativeReference, url, readOnly, sessionInitSQL, autoCommit);
     }
 
-    private DuckDBConnection(ByteBuffer connectionReference, String url, boolean readOnly, boolean autoCommit)
-        throws SQLException {
+    private DuckDBConnection(ByteBuffer connectionReference, String url, boolean readOnly, String sessionInitSQL,
+                             boolean autoCommit) throws SQLException {
         this.connRef = connectionReference;
         this.url = url;
         this.readOnly = readOnly;
         this.autoCommit = autoCommit;
+        this.sessionInitSQL = sessionInitSQL;
         // Hardcoded 'true' here is intentional, autocommit is handled in stmt#execute()
         DuckDBNative.duckdb_jdbc_set_auto_commit(connectionReference, true);
     }
@@ -95,7 +101,8 @@ public Connection duplicate() throws SQLException {
         connRefLock.lock();
         try {
             checkOpen();
-            return new DuckDBConnection(DuckDBNative.duckdb_jdbc_connect(connRef), url, readOnly, autoCommit);
+            return new DuckDBConnection(DuckDBNative.duckdb_jdbc_connect(connRef), url, readOnly, sessionInitSQL,
+                                        autoCommit);
         } finally {
             connRefLock.unlock();
         }
@@ -478,6 +485,10 @@ public DuckDBHugeInt createHugeInt(long lower, long upper) throws SQLException {
         return new DuckDBHugeInt(lower, upper);
     }
 
+    public String getSessionInitSQL() throws SQLException {
+        return sessionInitSQL;
+    }
+
     void checkOpen() throws SQLException {
         if (isClosed()) {
             throw new SQLException("Connection was closed");
diff --git a/src/main/java/org/duckdb/DuckDBDriver.java b/src/main/java/org/duckdb/DuckDBDriver.java
@@ -1,15 +1,23 @@
 package org.duckdb;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
+import static java.nio.file.StandardOpenOption.READ;
 import static org.duckdb.JdbcUtils.*;
+import static org.duckdb.io.IOUtils.readToString;
 
+import java.io.*;
 import java.nio.ByteBuffer;
+import java.nio.file.*;
+import java.security.DigestInputStream;
+import java.security.MessageDigest;
 import java.sql.*;
 import java.util.*;
 import java.util.concurrent.ScheduledThreadPoolExecutor;
 import java.util.concurrent.ThreadFactory;
 import java.util.concurrent.locks.ReentrantLock;
 import java.util.logging.Logger;
 import java.util.regex.Pattern;
+import org.duckdb.io.LimitedInputStream;
 
 public class DuckDBDriver implements java.sql.Driver {
 
@@ -41,6 +49,16 @@ public class DuckDBDriver implements java.sql.Driver {
     private static final Set<String> supportedOptions = new LinkedHashSet<>();
     private static final ReentrantLock supportedOptionsLock = new ReentrantLock();
 
+    private static final String SESSION_INIT_SQL_FILE_OPTION = "session_init_sql_file";
+    private static final String SESSION_INIT_SQL_FILE_SHA256_OPTION = "session_init_sql_file_sha256";
+    private static final long SESSION_INIT_SQL_FILE_MAX_SIZE_BYTES = 1 << 20; // 1MB
+    private static final String SESSION_INIT_SQL_FILE_URL_EXAMPLE =
+        "jdbc:duckdb:/path/to/db1.db;session_init_sql_file=/path/to/init.sql;session_init_sql_file_sha256=...";
+    private static final String SESSION_INIT_SQL_CONN_INIT_MARKER =
+        "/\\*\\s*DUCKDB_CONNECTION_INIT_BELOW_MARKER\\s*\\*/";
+    private static final LinkedHashSet<String> sessionInitSQLFileDbNames = new LinkedHashSet<>();
+    private static final ReentrantLock sessionInitSQLFileLock = new ReentrantLock();
+
     static {
         try {
             DriverManager.registerDriver(new DuckDBDriver());
@@ -65,6 +83,11 @@ public Connection connect(String url, Properties info) throws SQLException {
 
         // URL options
         ParsedProps pp = parsePropsFromUrl(url);
+
+        // Read session init file
+        SessionInitSQLFile sf = readSessionInitSQLFile(pp);
+
+        // Options in URL take preference
         for (Map.Entry<String, String> en : pp.props.entrySet()) {
             props.put(en.getKey(), en.getValue());
         }
@@ -107,11 +130,17 @@ public Connection connect(String url, Properties info) throws SQLException {
         boolean pinDBOpt = isStringTruish(pinDbOptStr, false);
 
         // Create connection
-        DuckDBConnection conn = DuckDBConnection.newConnection(shortUrl, readOnly, props);
-
-        pinDB(pinDBOpt, shortUrl, conn);
+        DuckDBConnection conn = DuckDBConnection.newConnection(shortUrl, readOnly, sf.origFileText, props);
 
-        initDucklake(conn, shortUrl, ducklake, ducklakeAlias);
+        // Run post-init
+        try {
+            pinDB(pinDBOpt, shortUrl, conn);
+            runSessionInitSQLFile(conn, url, sf);
+            initDucklake(conn, shortUrl, ducklake, ducklakeAlias);
+        } catch (SQLException e) {
+            closeQuietly(conn);
+            throw e;
+        }
 
         return conn;
     }
@@ -202,6 +231,7 @@ private static ParsedProps parsePropsFromUrl(String url) throws SQLException {
         }
         String[] parts = url.split(";");
         LinkedHashMap<String, String> props = new LinkedHashMap<>();
+        List<String> origPropNames = new ArrayList<>();
         for (int i = 1; i < parts.length; i++) {
             String entry = parts[i].trim();
             if (entry.isEmpty()) {
@@ -213,10 +243,11 @@ private static ParsedProps parsePropsFromUrl(String url) throws SQLException {
             }
             String key = kv[0].trim();
             String value = kv[1].trim();
+            origPropNames.add(key);
             props.put(key, value);
         }
         String shortUrl = parts[0].trim();
-        return new ParsedProps(shortUrl, props);
+        return new ParsedProps(shortUrl, props, origPropNames);
     }
 
     private static void pinDB(boolean pinnedDbOpt, String url, DuckDBConnection conn) throws SQLException {
@@ -306,17 +337,124 @@ private static void removeUnsupportedOptions(Properties props) throws SQLExcepti
         }
     }
 
+    private static SessionInitSQLFile readSessionInitSQLFile(ParsedProps pp) throws SQLException {
+        if (!pp.props.containsKey(SESSION_INIT_SQL_FILE_OPTION)) {
+            return new SessionInitSQLFile();
+        }
+
+        List<String> urlOptsList = new ArrayList<>(pp.props.keySet());
+
+        if (!SESSION_INIT_SQL_FILE_OPTION.equals(urlOptsList.get(0))) {
+            throw new SQLException(
+                "'session_init_sql_file' can only be specified as the first parameter in connection string,"
+                + " example: '" + SESSION_INIT_SQL_FILE_URL_EXAMPLE + "'");
+        }
+        for (int i = 1; i < pp.origPropNames.size(); i++) {
+            if (SESSION_INIT_SQL_FILE_OPTION.equalsIgnoreCase(pp.origPropNames.get(i))) {
+                throw new SQLException("'session_init_sql_file' option cannot be specified more than once");
+            }
+        }
+        String filePathStr = pp.props.remove(SESSION_INIT_SQL_FILE_OPTION);
+
+        final String expectedSha256;
+        if (pp.props.containsKey(SESSION_INIT_SQL_FILE_SHA256_OPTION)) {
+            if (!SESSION_INIT_SQL_FILE_SHA256_OPTION.equals(urlOptsList.get(1))) {
+                throw new SQLException(
+                    "'session_init_sql_file_sha256' can only be specified as the second parameter in connection string,"
+                    + " example: '" + SESSION_INIT_SQL_FILE_URL_EXAMPLE + "'");
+            }
+            for (int i = 2; i < pp.origPropNames.size(); i++) {
+                if (SESSION_INIT_SQL_FILE_SHA256_OPTION.equalsIgnoreCase(pp.origPropNames.get(i))) {
+                    throw new SQLException("'session_init_sql_file_sha256' option cannot be specified more than once");
+                }
+            }
+            expectedSha256 = pp.props.remove(SESSION_INIT_SQL_FILE_SHA256_OPTION);
+        } else {
+            expectedSha256 = "";
+        }
+
+        Path filePath = Paths.get(filePathStr);
+        if (!Files.exists(filePath)) {
+            throw new SQLException("Specified session init SQL file not found, path: " + filePath);
+        }
+
+        final String origFileText;
+        final String actualSha256;
+        try {
+            long fileSize = Files.size(filePath);
+            if (fileSize > SESSION_INIT_SQL_FILE_MAX_SIZE_BYTES) {
+                throw new SQLException("Specified session init SQL file size: " + fileSize +
+                                       " exceeds max allowed size: " + SESSION_INIT_SQL_FILE_MAX_SIZE_BYTES);
+            }
+            MessageDigest md = MessageDigest.getInstance("SHA-256");
+            try (InputStream is = new DigestInputStream(
+                     new LimitedInputStream(Files.newInputStream(filePath, READ), fileSize), md)) {
+                Reader reader = new InputStreamReader(is, UTF_8);
+                origFileText = readToString(reader);
+                actualSha256 = bytesToHex(md.digest());
+            }
+        } catch (Exception e) {
+            throw new SQLException(e);
+        }
+
+        if (!expectedSha256.isEmpty() && !expectedSha256.toLowerCase().equals(actualSha256)) {
+            throw new SQLException("Session init SQL file SHA-256 mismatch, expected: " + expectedSha256 +
+                                   ", actual: " + actualSha256);
+        }
+
+        String[] parts = origFileText.split(SESSION_INIT_SQL_CONN_INIT_MARKER);
+        if (parts.length > 2) {
+            throw new SQLException("Connection init marker: '" + SESSION_INIT_SQL_CONN_INIT_MARKER +
+                                   "' can only be specified once");
+        }
+        if (1 == parts.length) {
+            return new SessionInitSQLFile(origFileText, parts[0].trim());
+        } else {
+            return new SessionInitSQLFile(origFileText, parts[0].trim(), parts[1].trim());
+        }
+    }
+
+    private static void runSessionInitSQLFile(Connection conn, String url, SessionInitSQLFile sf) throws SQLException {
+        if (sf.isEmpty()) {
+            return;
+        }
+        sessionInitSQLFileLock.lock();
+        try {
+
+            if (!sf.dbInitSQL.isEmpty()) {
+                String dbName = dbNameFromUrl(url);
+                if (MEMORY_DB.equals(dbName) || !sessionInitSQLFileDbNames.contains(dbName)) {
+                    try (Statement stmt = conn.createStatement()) {
+                        stmt.execute(sf.dbInitSQL);
+                    }
+                }
+                sessionInitSQLFileDbNames.add(dbName);
+            }
+
+            if (!sf.connInitSQL.isEmpty()) {
+                try (Statement stmt = conn.createStatement()) {
+                    stmt.execute(sf.connInitSQL);
+                }
+            }
+
+        } finally {
+            sessionInitSQLFileLock.unlock();
+        }
+    }
+
     private static class ParsedProps {
         final String shortUrl;
         final LinkedHashMap<String, String> props;
+        final List<String> origPropNames;
 
         private ParsedProps(String url) {
-            this(url, new LinkedHashMap<>());
+            this(url, new LinkedHashMap<>(), new ArrayList<>());
         }
 
-        private ParsedProps(String shortUrl, LinkedHashMap<String, String> props) {
+        private ParsedProps(String shortUrl, LinkedHashMap<String, String> props, List<String> origPropNames) {
             this.shortUrl = shortUrl;
             this.props = props;
+            this.origPropNames = origPropNames;
         }
     }
 
@@ -338,4 +476,28 @@ public void run() {
             }
         }
     }
+
+    private static class SessionInitSQLFile {
+        final String dbInitSQL;
+        final String connInitSQL;
+        final String origFileText;
+
+        private SessionInitSQLFile() {
+            this(null, null, null);
+        }
+
+        private SessionInitSQLFile(String origFileText, String dbInitSQL) {
+            this(origFileText, dbInitSQL, "");
+        }
+
+        private SessionInitSQLFile(String origFileText, String dbInitSQL, String connInitSQL) {
+            this.origFileText = origFileText;
+            this.dbInitSQL = dbInitSQL;
+            this.connInitSQL = connInitSQL;
+        }
+
+        boolean isEmpty() {
+            return null == dbInitSQL && null == connInitSQL && null == origFileText;
+        }
+    }
 }
diff --git a/src/main/java/org/duckdb/JdbcUtils.java b/src/main/java/org/duckdb/JdbcUtils.java
@@ -75,4 +75,26 @@ static String dbNameFromUrl(String url) throws SQLException {
         }
         return dbName;
     }
+
+    static String bytesToHex(byte[] bytes) {
+        if (null == bytes) {
+            return "";
+        }
+        StringBuilder sb = new StringBuilder(bytes.length * 2);
+        for (byte b : bytes) {
+            sb.append(String.format("%02x", b));
+        }
+        return sb.toString();
+    }
+
+    static void closeQuietly(AutoCloseable closeable) {
+        if (null == closeable) {
+            return;
+        }
+        try {
+            closeable.close();
+        } catch (Exception e) {
+            // suppress
+        }
+    }
 }
diff --git a/src/test/java/org/duckdb/TestDuckDBJDBC.java b/src/test/java/org/duckdb/TestDuckDBJDBC.java
@@ -3674,7 +3674,7 @@ public static void main(String[] args) throws Exception {
         } else {
             statusCode = runTests(args, TestDuckDBJDBC.class, TestBatch.class, TestClosure.class,
                                   TestExtensionTypes.class, TestSpatial.class, TestParameterMetadata.class,
-                                  TestPrepare.class, TestResults.class, TestTimestamp.class);
+                                  TestPrepare.class, TestResults.class, TestSessionInit.class, TestTimestamp.class);
         }
         System.exit(statusCode);
     }
diff --git a/src/test/java/org/duckdb/TestSessionInit.java b/src/test/java/org/duckdb/TestSessionInit.java
diff --git a/src/test/java/org/duckdb/test/TempDirectory.java b/src/test/java/org/duckdb/test/TempDirectory.java

Original file line number	Diff line number	Diff line change
`@@ -3674,7 +3674,7 @@ public static void main(String[] args) throws Exception {`
`3674`	`3674`	`} else {`
`3675`	`3675`	`statusCode = runTests(args, TestDuckDBJDBC.class, TestBatch.class, TestClosure.class,`
`3676`	`3676`	`TestExtensionTypes.class, TestSpatial.class, TestParameterMetadata.class,`
`3677`		`- TestPrepare.class, TestResults.class, TestTimestamp.class);`
	`3677`	`+ TestPrepare.class, TestResults.class, TestSessionInit.class, TestTimestamp.class);`
`3678`	`3678`	`}`
`3679`	`3679`	`System.exit(statusCode);`
`3680`	`3680`	`}`