1 files changed, 368 insertions, 0 deletions
diff --git a/servers/slapd/module.c b/servers/slapd/module.c
new file mode 100644
index 0000000..c775a28
--- /dev/null
+++ b/servers/slapd/module.c
@@ -0,0 +1,368 @@
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 1998-2021 The OpenLDAP Foundation.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted only as authorized by the OpenLDAP
+ * Public License.
+ *
+ * A copy of this license is available in the file LICENSE in the
+ * top-level directory of the distribution or, alternatively, at
+ * <http://www.OpenLDAP.org/license.html>.
+ */
+
+#include "portable.h"
+#include <stdio.h>
+#include "slap.h"
+
+#ifdef SLAPD_MODULES
+
+#include <ltdl.h>
+
+typedef int (*MODULE_INIT_FN)(
+	int argc,
+	char *argv[]);
+typedef int (*MODULE_LOAD_FN)(
+	const void *module,
+	const char *filename);
+typedef int (*MODULE_TERM_FN)(void);
+
+
+struct module_regtable_t {
+	char *type;
+	MODULE_LOAD_FN proc;
+} module_regtable[] = {
+		{ "null", load_null_module },
+#ifdef SLAPD_EXTERNAL_EXTENSIONS
+		{ "extension", load_extop_module },
+#endif
+		{ NULL, NULL }
+};
+
+typedef struct module_loaded_t {
+	struct module_loaded_t *next;
+	lt_dlhandle lib;
+	char name[1];
+} module_loaded_t;
+
+module_loaded_t *module_list = NULL;
+
+static int module_int_unload (module_loaded_t *module);
+
+#ifdef HAVE_EBCDIC
+static char ebuf[BUFSIZ];
+#endif
+
+int module_init (void)
+{
+	if (lt_dlinit()) {
+		const char *error = lt_dlerror();
+#ifdef HAVE_EBCDIC
+		strcpy( ebuf, error );
+		__etoa( ebuf );
+		error = ebuf;
+#endif
+		Debug(LDAP_DEBUG_ANY, "lt_dlinit failed: %s\n", error, 0, 0);
+
+		return -1;
+	}
+
+	return module_path( LDAP_MODULEDIR );
+}
+
+int module_kill (void)
+{
+	/* unload all modules before shutdown */
+	while (module_list != NULL) {
+		module_int_unload(module_list);
+	}
+
+	if (lt_dlexit()) {
+		const char *error = lt_dlerror();
+#ifdef HAVE_EBCDIC
+		strcpy( ebuf, error );
+		__etoa( ebuf );
+		error = ebuf;
+#endif
+		Debug(LDAP_DEBUG_ANY, "lt_dlexit failed: %s\n", error, 0, 0);
+
+		return -1;
+	}
+	return 0;
+}
+
+void * module_handle( const char *file_name )
+{
+	module_loaded_t *module;
+
+	for ( module = module_list; module; module= module->next ) {
+		if ( !strcmp( module->name, file_name )) {
+			return module;
+		}
+	}
+	return NULL;
+}
+
+int module_unload( const char *file_name )
+{
+	module_loaded_t *module;
+
+	module = module_handle( file_name );
+	if ( module ) {
+		module_int_unload( module );
+		return 0;
+	}
+	return -1;	/* not found */
+}
+
+int module_load(const char* file_name, int argc, char *argv[])
+{
+	module_loaded_t *module;
+	const char *error;
+	int rc;
+	MODULE_INIT_FN initialize;
+#ifdef HAVE_EBCDIC
+#define	file	ebuf
+#else
+#define	file	file_name
+#endif
+
+	module = module_handle( file_name );
+	if ( module ) {
+		Debug( LDAP_DEBUG_ANY, "module_load: (%s) already loaded\n",
+			file_name, 0, 0 );
+		return -1;
+	}
+
+	/* If loading a backend, see if we already have it */
+	if ( !strncasecmp( file_name, "back_", 5 )) {
+		char *name = (char *)file_name + 5;
+		char *dot = strchr( name, '.');
+		if (dot) *dot = '\0';
+		rc = backend_info( name ) != NULL;
+		if (dot) *dot = '.';
+		if ( rc ) {
+			Debug( LDAP_DEBUG_CONFIG, "module_load: (%s) already present (static)\n",
+				file_name, 0, 0 );
+			return 0;
+		}
+	} else {
+		/* check for overlays too */
+		char *dot = strchr( file_name, '.' );
+		if ( dot ) *dot = '\0';
+		rc = overlay_find( file_name ) != NULL;
+		if ( dot ) *dot = '.';
+		if ( rc ) {
+			Debug( LDAP_DEBUG_CONFIG, "module_load: (%s) already present (static)\n",
+				file_name, 0, 0 );
+			return 0;
+		}
+	}
+
+	module = (module_loaded_t *)ch_calloc(1, sizeof(module_loaded_t) +
+		strlen(file_name));
+	if (module == NULL) {
+		Debug(LDAP_DEBUG_ANY, "module_load failed: (%s) out of memory\n", file_name,
+			0, 0);
+
+		return -1;
+	}
+	strcpy( module->name, file_name );
+
+#ifdef HAVE_EBCDIC
+	strcpy( file, file_name );
+	__atoe( file );
+#endif
+	/*
+	 * The result of lt_dlerror(), when called, must be cached prior
+	 * to calling Debug. This is because Debug is a macro that expands
+	 * into multiple function calls.
+	 */
+	if ((module->lib = lt_dlopenext(file)) == NULL) {
+		error = lt_dlerror();
+#ifdef HAVE_EBCDIC
+		strcpy( ebuf, error );
+		__etoa( ebuf );
+		error = ebuf;
+#endif
+		Debug(LDAP_DEBUG_ANY, "lt_dlopenext failed: (%s) %s\n", file_name,
+			error, 0);
+
+		ch_free(module);
+		return -1;
+	}
+
+	Debug(LDAP_DEBUG_CONFIG, "loaded module %s\n", file_name, 0, 0);
+
+   
+#ifdef HAVE_EBCDIC
+#pragma convlit(suspend)
+#endif
+	if ((initialize = lt_dlsym(module->lib, "init_module")) == NULL) {
+#ifdef HAVE_EBCDIC
+#pragma convlit(resume)
+#endif
+		Debug(LDAP_DEBUG_CONFIG, "module %s: no init_module() function found\n",
+			file_name, 0, 0);
+
+		lt_dlclose(module->lib);
+		ch_free(module);
+		return -1;
+	}
+
+	/* The imported init_module() routine passes back the type of
+	 * module (i.e., which part of slapd it should be hooked into)
+	 * or -1 for error.  If it passes back 0, then you get the 
+	 * old behavior (i.e., the library is loaded and not hooked
+	 * into anything).
+	 *
+	 * It might be better if the conf file could specify the type
+	 * of module.  That way, a single module could support multiple
+	 * type of hooks. This could be done by using something like:
+	 *
+	 *    moduleload extension /usr/local/openldap/whatever.so
+	 *
+	 * then we'd search through module_regtable for a matching
+	 * module type, and hook in there.
+	 */
+	rc = initialize(argc, argv);
+	if (rc == -1) {
+		Debug(LDAP_DEBUG_CONFIG, "module %s: init_module() failed\n",
+			file_name, 0, 0);
+
+		lt_dlclose(module->lib);
+		ch_free(module);
+		return rc;
+	}
+
+	if (rc >= (int)(sizeof(module_regtable) / sizeof(struct module_regtable_t))
+		|| module_regtable[rc].proc == NULL)
+	{
+		Debug(LDAP_DEBUG_CONFIG, "module %s: unknown registration type (%d)\n",
+			file_name, rc, 0);
+
+		module_int_unload(module);
+		return -1;
+	}
+
+	rc = (module_regtable[rc].proc)(module, file_name);
+	if (rc != 0) {
+		Debug(LDAP_DEBUG_CONFIG, "module %s: %s module could not be registered\n",
+			file_name, module_regtable[rc].type, 0);
+
+		module_int_unload(module);
+		return rc;
+	}
+
+	module->next = module_list;
+	module_list = module;
+
+	Debug(LDAP_DEBUG_CONFIG, "module %s: %s module registered\n",
+		file_name, module_regtable[rc].type, 0);
+
+	return 0;
+}
+
+int module_path(const char *path)
+{
+#ifdef HAVE_EBCDIC
+	strcpy(ebuf, path);
+	__atoe(ebuf);
+	path = ebuf;
+#endif
+	return lt_dlsetsearchpath( path );
+}
+
+void *module_resolve (const void *module, const char *name)
+{
+#ifdef HAVE_EBCDIC
+	strcpy(ebuf, name);
+	__atoe(ebuf);
+	name = ebuf;
+#endif
+	if (module == NULL || name == NULL)
+		return(NULL);
+	return(lt_dlsym(((module_loaded_t *)module)->lib, name));
+}
+
+static int module_int_unload (module_loaded_t *module)
+{
+	module_loaded_t *mod;
+	MODULE_TERM_FN terminate;
+
+	if (module != NULL) {
+		/* remove module from tracking list */
+		if (module_list == module) {
+			module_list = module->next;
+		} else {
+			for (mod = module_list; mod; mod = mod->next) {
+				if (mod->next == module) {
+					mod->next = module->next;
+					break;
+				}
+			}
+		}
+
+		/* call module's terminate routine, if present */
+#ifdef HAVE_EBCDIC
+#pragma convlit(suspend)
+#endif
+		if ((terminate = lt_dlsym(module->lib, "term_module"))) {
+#ifdef HAVE_EBCDIC
+#pragma convlit(resume)
+#endif
+			terminate();
+		}
+
+		/* close the library and free the memory */
+		lt_dlclose(module->lib);
+		ch_free(module);
+	}
+	return 0;
+}
+
+int load_null_module (const void *module, const char *file_name)
+{
+	return 0;
+}
+
+#ifdef SLAPD_EXTERNAL_EXTENSIONS
+int
+load_extop_module (
+	const void *module,
+	const char *file_name
+)
+{
+	SLAP_EXTOP_MAIN_FN *ext_main;
+	SLAP_EXTOP_GETOID_FN *ext_getoid;
+	struct berval oid;
+	int rc;
+
+	ext_main = (SLAP_EXTOP_MAIN_FN *)module_resolve(module, "ext_main");
+	if (ext_main == NULL) {
+		return(-1);
+	}
+
+	ext_getoid = module_resolve(module, "ext_getoid");
+	if (ext_getoid == NULL) {
+		return(-1);
+	}
+
+	rc = (ext_getoid)(0, &oid, 256);
+	if (rc != 0) {
+		return(rc);
+	}
+	if (oid.bv_val == NULL || oid.bv_len == 0) {
+		return(-1);
+	}
+
+	/* FIXME: this is broken, and no longer needed, 
+	 * as a module can call load_extop() itself... */
+	rc = load_extop( &oid, ext_main );
+	return rc;
+}
+#endif /* SLAPD_EXTERNAL_EXTENSIONS */
+#endif /* SLAPD_MODULES */
+