Enable the load extension API (#39)

Expose the C API version of the enable load extension functionality. The SQL version is not enabled when calling EnableLoadExtension().
crawshaw · Aug 25, 2018 · ac13ea4 · ac13ea4
1 parent 9079bee
commit ac13ea4
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diff --git a/extension.go b/extension.go
@@ -0,0 +1,57 @@
+// Copyright (c) 2018 David Crawshaw <david@zentus.com>
+//
+// Permission to use, copy, modify, and distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+package sqlite
+
+import "unsafe"
+
+// #include <stdlib.h>
+// #include <sqlite3.h>
+// static int db_config_onoff(sqlite3* db, int op, int onoff) {
+//   return sqlite3_db_config(db, op, onoff);
+// }
+import "C"
+
+const (
+	SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION = C.int(C.SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION)
+)
+
+// EnableLoadExtension allows extensions to be loaded via LoadExtension().  The
+// SQL interface is left disabled as recommended.
+// https://www.sqlite.org/c3ref/enable_load_extension.html
+func (conn *Conn) EnableLoadExtension(on bool) error {
+	var enable C.int
+	if on {
+		enable = 1
+	}
+	res := C.db_config_onoff(conn.conn, SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION, enable)
+	return reserr("Conn.EnableLoadExtension", "", "", res)
+}
+
+// LoadExtension attempts to load a runtime-loadable extension.
+// https://www.sqlite.org/c3ref/load_extension.html
+func (conn *Conn) LoadExtension(ext, entry string) error {
+	cext := C.CString(ext)
+	defer C.free(unsafe.Pointer(cext))
+	var centry *C.char
+	if entry != "" {
+		centry = C.CString(entry)
+		defer C.free(unsafe.Pointer(centry))
+	}
+	var cerr *C.char
+	res := C.sqlite3_load_extension(conn.conn, cext, centry, &cerr)
+	err := C.GoString(cerr)
+	C.sqlite3_free(unsafe.Pointer(cerr))
+	return reserr("Conn.LoadExtension", "", err, res)
+}
diff --git a/extension_test.go b/extension_test.go
@@ -0,0 +1,130 @@
+// Copyright (c) 2018 David Crawshaw <david@zentus.com>
+//
+// Permission to use, copy, modify, and distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+package sqlite_test
+
+import (
+	"io"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"runtime"
+	"strings"
+	"testing"
+
+	"crawshaw.io/sqlite"
+)
+
+const (
+	extCode = `
+#include "sqlite3ext.h"
+SQLITE_EXTENSION_INIT1
+
+#include <stdlib.h>
+
+static void hellofunc(
+	sqlite3_context *context,
+	int argc,
+	sqlite3_value **argv){
+		(void)argc;
+		(void)argv;
+		sqlite3_result_text(context, "Hello, World!", -1, SQLITE_STATIC);
+	}
+
+#ifdef _WIN32
+__declspec(dllexport)
+#endif
+int sqlite3_hello_init(
+	sqlite3 *db,
+	char **pzErrMsg,
+	const sqlite3_api_routines *pApi
+){
+		int rc = SQLITE_OK;
+		SQLITE_EXTENSION_INIT2(pApi);
+		(void)pzErrMsg;  /* Unused parameter */
+		return sqlite3_create_function(db, "hello", 0, SQLITE_UTF8, 0, hellofunc, 0, 0);
+}`
+)
+
+func TestLoadExtension(t *testing.T) {
+	tmpdir, err := ioutil.TempDir("", "sqlite")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(tmpdir)
+	fout, err := os.Create(filepath.Join(tmpdir, "ext.c"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if _, err = io.Copy(fout, strings.NewReader(extCode)); err != nil {
+		t.Fatal(err)
+	}
+	if err = fout.Close(); err != nil {
+		t.Error(err)
+	}
+	include, err := os.Getwd()
+	if err != nil {
+		t.Fatal(err)
+	}
+	var args []string
+	switch runtime.GOOS {
+	// See https://www.sqlite.org/loadext.html#build
+	case "darwin":
+		args = []string{"gcc", "-g", "-fPIC", "-I" + include, "-dynamiclib", "ext.c", "-o", "libhello.dylib"}
+	case "linux":
+		args = []string{"gcc", "-g", "-fPIC", "-I" + include, "-shared", "ext.c", "-o", "libhello.so"}
+	case "windows":
+		// TODO: add windows support
+		fallthrough
+	default:
+		t.Skipf("unsupported OS: %s", runtime.GOOS)
+	}
+	cmd := exec.Command(args[0], args[1:]...)
+	cmd.Dir = tmpdir
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		t.Skipf("no gcc support: %s, %s", string(out), err)
+	}
+	c, err := sqlite.OpenConn(":memory:", 0)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer func() {
+		err := c.Close()
+		if err != nil {
+			t.Error(err)
+		}
+	}()
+	libPath := filepath.Join(tmpdir, args[len(args)-1])
+	err = c.LoadExtension(libPath, "")
+	if err == nil {
+		t.Error("loaded extension without enabling load extension")
+	}
+	err = c.EnableLoadExtension(true)
+	if err != nil {
+		t.Fatal(err)
+	}
+	err = c.LoadExtension(libPath, "")
+	if err != nil {
+		t.Fatal(err)
+	}
+	stmt := c.Prep("SELECT hello();")
+	if _, err := stmt.Step(); err != nil {
+		t.Fatal(err)
+	}
+	if got, want := stmt.ColumnText(0), "Hello, World!"; got != want {
+		t.Error("failed to load extension, got: %s, want: %s", got, want)
+	}
+}