17 files changed, 1514 insertions, 0 deletions

diff --git a/servers/slapd/back-shell/Makefile.in b/servers/slapd/back-shell/Makefile.in
new file mode 100644
index 0000000..1fed787
--- /dev/null
+++ b/servers/slapd/back-shell/Makefile.in
@@ -0,0 +1,43 @@
+# Makefile.in for back-shell
+# $OpenLDAP$
+## 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>.
+
+SRCS	= init.c config.c fork.c search.c bind.c unbind.c add.c \
+		delete.c modify.c modrdn.c compare.c result.c
+OBJS	= init.lo config.lo fork.lo search.lo bind.lo unbind.lo add.lo \
+		delete.lo modify.lo modrdn.lo compare.lo result.lo
+
+LDAP_INCDIR= ../../../include       
+LDAP_LIBDIR= ../../../libraries
+
+BUILD_OPT = "--enable-shell"
+BUILD_MOD = @BUILD_SHELL@
+
+mod_DEFS = -DSLAPD_IMPORT
+MOD_DEFS = $(@BUILD_SHELL@_DEFS)
+
+shared_LDAP_LIBS = $(LDAP_LIBLDAP_R_LA) $(LDAP_LIBLBER_LA)
+NT_LINK_LIBS = -L.. -lslapd $(@BUILD_LIBS_DYNAMIC@_LDAP_LIBS)
+UNIX_LINK_LIBS = $(@BUILD_LIBS_DYNAMIC@_LDAP_LIBS)
+
+LIBBASE = back_shell
+
+XINCPATH = -I.. -I$(srcdir)/..
+XDEFS = $(MODULES_CPPFLAGS)
+
+all-local-lib:	../.backend
+
+../.backend: lib$(LIBBASE).a
+	@touch $@
+
diff --git a/servers/slapd/back-shell/add.c b/servers/slapd/back-shell/add.c
new file mode 100644
index 0000000..19a96d1
--- /dev/null
+++ b/servers/slapd/back-shell/add.c
@@ -0,0 +1,84 @@
+/* add.c - shell backend add function */
+/* $OpenLDAP$ */
+/* 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>.
+ */
+/* Portions Copyright (c) 1995 Regents of the University of Michigan.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that this notice is preserved and that due credit is given
+ * to the University of Michigan at Ann Arbor. The name of the University
+ * may not be used to endorse or promote products derived from this
+ * software without specific prior written permission. This software
+ * is provided ``as is'' without express or implied warranty.
+ */
+/* ACKNOWLEDGEMENTS:
+ * This work was originally developed by the University of Michigan
+ * (as part of U-MICH LDAP).
+ */
+
+#include "portable.h"
+
+#include <stdio.h>
+
+#include <ac/string.h>
+#include <ac/socket.h>
+
+#include "slap.h"
+#include "shell.h"
+
+int
+shell_back_add(
+    Operation	*op,
+    SlapReply	*rs )
+{
+	struct shellinfo	*si = (struct shellinfo *) op->o_bd->be_private;
+	AttributeDescription *entry = slap_schema.si_ad_entry;
+	FILE			*rfp, *wfp;
+	int			len;
+
+	if ( si->si_add == NULL ) {
+		send_ldap_error( op, rs, LDAP_UNWILLING_TO_PERFORM,
+		    "add not implemented" );
+		return( -1 );
+	}
+
+	if ( ! access_allowed( op, op->oq_add.rs_e,
+		entry, NULL, ACL_WADD, NULL ) )
+	{
+		send_ldap_error( op, rs, LDAP_INSUFFICIENT_ACCESS, NULL );
+		return -1;
+	}
+
+	if ( forkandexec( si->si_add, &rfp, &wfp ) == (pid_t)-1 ) {
+		send_ldap_error( op, rs, LDAP_OTHER,
+		    "could not fork/exec" );
+		return( -1 );
+	}
+
+	/* write out the request to the add process */
+	fprintf( wfp, "ADD\n" );
+	fprintf( wfp, "msgid: %ld\n", (long) op->o_msgid );
+	print_suffixes( wfp, op->o_bd );
+	ldap_pvt_thread_mutex_lock( &entry2str_mutex );
+	fprintf( wfp, "%s", entry2str( op->oq_add.rs_e, &len ) );
+	ldap_pvt_thread_mutex_unlock( &entry2str_mutex );
+	fclose( wfp );
+
+	/* read in the result and send it along */
+	read_and_send_results( op, rs, rfp );
+
+	fclose( rfp );
+	return( 0 );
+}
diff --git a/servers/slapd/back-shell/bind.c b/servers/slapd/back-shell/bind.c
new file mode 100644
index 0000000..28b9e05
--- /dev/null
+++ b/servers/slapd/back-shell/bind.c
@@ -0,0 +1,105 @@
+/* bind.c - shell backend bind function */
+/* $OpenLDAP$ */
+/* 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>.
+ */
+/* Portions Copyright (c) 1995 Regents of the University of Michigan.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that this notice is preserved and that due credit is given
+ * to the University of Michigan at Ann Arbor. The name of the University
+ * may not be used to endorse or promote products derived from this
+ * software without specific prior written permission. This software
+ * is provided ``as is'' without express or implied warranty.
+ */
+/* ACKNOWLEDGEMENTS:
+ * This work was originally developed by the University of Michigan
+ * (as part of U-MICH LDAP).
+ */
+
+#include "portable.h"
+
+#include <stdio.h>
+
+#include <ac/socket.h>
+#include <ac/string.h>
+
+#include "slap.h"
+#include "shell.h"
+
+int
+shell_back_bind(
+    Operation		*op,
+    SlapReply		*rs )
+{
+	struct shellinfo	*si = (struct shellinfo *) op->o_bd->be_private;
+	AttributeDescription *entry = slap_schema.si_ad_entry;
+	Entry e;
+	FILE			*rfp, *wfp;
+	int			rc;
+
+	/* allow rootdn as a means to auth without the need to actually
+ 	 * contact the proxied DSA */
+	switch ( be_rootdn_bind( op, rs ) ) {
+	case SLAP_CB_CONTINUE:
+		break;
+
+	default:
+		return rs->sr_err;
+	}
+
+	if ( si->si_bind == NULL ) {
+		send_ldap_error( op, rs, LDAP_UNWILLING_TO_PERFORM,
+		    "bind not implemented" );
+		return( -1 );
+	}
+
+	e.e_id = NOID;
+	e.e_name = op->o_req_dn;
+	e.e_nname = op->o_req_ndn;
+	e.e_attrs = NULL;
+	e.e_ocflags = 0;
+	e.e_bv.bv_len = 0;
+	e.e_bv.bv_val = NULL;
+	e.e_private = NULL;
+
+	if ( ! access_allowed( op, &e,
+		entry, NULL, ACL_AUTH, NULL ) )
+	{
+		send_ldap_error( op, rs, LDAP_INSUFFICIENT_ACCESS, NULL );
+		return -1;
+	}
+
+	if ( forkandexec( si->si_bind, &rfp, &wfp ) == (pid_t)-1 ) {
+		send_ldap_error( op, rs, LDAP_OTHER,
+		    "could not fork/exec" );
+		return( -1 );
+	}
+
+	/* write out the request to the bind process */
+	fprintf( wfp, "BIND\n" );
+	fprintf( wfp, "msgid: %ld\n", (long) op->o_msgid );
+	print_suffixes( wfp, op->o_bd );
+	fprintf( wfp, "dn: %s\n", op->o_req_dn.bv_val );
+	fprintf( wfp, "method: %d\n", op->oq_bind.rb_method );
+	fprintf( wfp, "credlen: %lu\n", op->oq_bind.rb_cred.bv_len );
+	fprintf( wfp, "cred: %s\n", op->oq_bind.rb_cred.bv_val ); /* XXX */
+	fclose( wfp );
+
+	/* read in the results and send them along */
+	rc = read_and_send_results( op, rs, rfp );
+	fclose( rfp );
+
+	return( rc );
+}
diff --git a/servers/slapd/back-shell/compare.c b/servers/slapd/back-shell/compare.c
new file mode 100644
index 0000000..2b1949a
--- /dev/null
+++ b/servers/slapd/back-shell/compare.c
@@ -0,0 +1,99 @@
+/* compare.c - shell backend compare function */
+/* $OpenLDAP$ */
+/* 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>.
+ */
+/* Portions Copyright (c) 1995 Regents of the University of Michigan.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that this notice is preserved and that due credit is given
+ * to the University of Michigan at Ann Arbor. The name of the University
+ * may not be used to endorse or promote products derived from this
+ * software without specific prior written permission. This software
+ * is provided ``as is'' without express or implied warranty.
+ */
+/* ACKNOWLEDGEMENTS:
+ * This work was originally developed by the University of Michigan
+ * (as part of U-MICH LDAP).
+ */
+
+#include "portable.h"
+
+#include <stdio.h>
+
+#include <ac/string.h>
+#include <ac/socket.h>
+
+#include "slap.h"
+#include "shell.h"
+
+int
+shell_back_compare(
+    Operation	*op,
+    SlapReply	*rs )
+{
+	struct shellinfo	*si = (struct shellinfo *) op->o_bd->be_private;
+	AttributeDescription *entry = slap_schema.si_ad_entry;
+	Entry e;
+	FILE			*rfp, *wfp;
+
+	if ( si->si_compare == NULL ) {
+		send_ldap_error( op, rs, LDAP_UNWILLING_TO_PERFORM,
+		    "compare not implemented" );
+		return( -1 );
+	}
+
+	e.e_id = NOID;
+	e.e_name = op->o_req_dn;
+	e.e_nname = op->o_req_ndn;
+	e.e_attrs = NULL;
+	e.e_ocflags = 0;
+	e.e_bv.bv_len = 0;
+	e.e_bv.bv_val = NULL;
+	e.e_private = NULL;
+
+	if ( ! access_allowed( op, &e,
+		entry, NULL, ACL_READ, NULL ) )
+	{
+		send_ldap_error( op, rs, LDAP_INSUFFICIENT_ACCESS, NULL );
+		return -1;
+	}
+
+	if ( forkandexec( si->si_compare, &rfp, &wfp ) == (pid_t)-1 ) {
+		send_ldap_error( op, rs, LDAP_OTHER,
+		    "could not fork/exec" );
+		return( -1 );
+	}
+
+	/*
+	 * FIX ME:  This should use LDIF routines so that binary
+	 *	values are properly dealt with
+	 */
+
+	/* write out the request to the compare process */
+	fprintf( wfp, "COMPARE\n" );
+	fprintf( wfp, "msgid: %ld\n", (long) op->o_msgid );
+	print_suffixes( wfp, op->o_bd );
+	fprintf( wfp, "dn: %s\n", op->o_req_dn.bv_val );
+	fprintf( wfp, "%s: %s\n",
+		op->oq_compare.rs_ava->aa_desc->ad_cname.bv_val,
+		op->oq_compare.rs_ava->aa_value.bv_val /* could be binary! */ );
+	fclose( wfp );
+
+	/* read in the result and send it along */
+	read_and_send_results( op, rs, rfp );
+
+	fclose( rfp );
+	return( 0 );
+}
diff --git a/servers/slapd/back-shell/config.c b/servers/slapd/back-shell/config.c
new file mode 100644
index 0000000..3b99e35
--- /dev/null
+++ b/servers/slapd/back-shell/config.c
@@ -0,0 +1,137 @@
+/* config.c - shell backend configuration file routine */
+/* $OpenLDAP$ */
+/* 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>.
+ */
+/* Portions Copyright (c) 1995 Regents of the University of Michigan.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that this notice is preserved and that due credit is given
+ * to the University of Michigan at Ann Arbor. The name of the University
+ * may not be used to endorse or promote products derived from this
+ * software without specific prior written permission. This software
+ * is provided ``as is'' without express or implied warranty.
+ */
+/* ACKNOWLEDGEMENTS:
+ * This work was originally developed by the University of Michigan
+ * (as part of U-MICH LDAP).
+ */
+
+#include "portable.h"
+
+#include <stdio.h>
+
+#include <ac/string.h>
+#include <ac/socket.h>
+
+#include "slap.h"
+#include "shell.h"
+#include "config.h"
+
+static ConfigDriver shell_cf;
+
+enum {
+	SHELL_BIND = 0,
+	SHELL_UNBIND = 1,
+	SHELL_SEARCH,
+	SHELL_COMPARE,
+	SHELL_MODIFY,
+	SHELL_MODRDN,
+	SHELL_ADD,
+	SHELL_DELETE
+};
+
+static ConfigTable shellcfg[] = {
+	{ "bind", "args", 2, 0, 0, ARG_MAGIC|SHELL_BIND, shell_cf,
+		"( OLcfgDbAt:10.1 NAME 'olcShellBind' "
+			"DESC 'Bind command and arguments' "
+			"EQUALITY caseExactMatch "
+			"SYNTAX OMsDirectoryString SINGLE-VALUE ) ", NULL, NULL },
+	{ "unbind", "args", 2, 0, 0, ARG_MAGIC|SHELL_UNBIND, shell_cf,
+		"( OLcfgDbAt:10.2 NAME 'olcShellUnbind' "
+			"DESC 'Unbind command and arguments' "
+			"EQUALITY caseExactMatch "
+			"SYNTAX OMsDirectoryString SINGLE-VALUE ) ", NULL, NULL },
+	{ "search", "args", 2, 0, 0, ARG_MAGIC|SHELL_SEARCH, shell_cf,
+		"( OLcfgDbAt:10.3 NAME 'olcShellSearch' "
+			"DESC 'Search command and arguments' "
+			"EQUALITY caseExactMatch "
+			"SYNTAX OMsDirectoryString SINGLE-VALUE ) ", NULL, NULL },
+	{ "compare", "args", 2, 0, 0, ARG_MAGIC|SHELL_COMPARE, shell_cf,
+		"( OLcfgDbAt:10.4 NAME 'olcShellCompare' "
+			"DESC 'Compare command and arguments' "
+			"EQUALITY caseExactMatch "
+			"SYNTAX OMsDirectoryString SINGLE-VALUE ) ", NULL, NULL },
+	{ "modify", "args", 2, 0, 0, ARG_MAGIC|SHELL_MODIFY, shell_cf,
+		"( OLcfgDbAt:10.5 NAME 'olcShellModify' "
+			"DESC 'Modify command and arguments' "
+			"EQUALITY caseExactMatch "
+			"SYNTAX OMsDirectoryString SINGLE-VALUE ) ", NULL, NULL },
+	{ "modrdn", "args", 2, 0, 0, ARG_MAGIC|SHELL_MODRDN, shell_cf,
+		"( OLcfgDbAt:10.6 NAME 'olcShellModRDN' "
+			"DESC 'ModRDN command and arguments' "
+			"EQUALITY caseExactMatch "
+			"SYNTAX OMsDirectoryString SINGLE-VALUE ) ", NULL, NULL },
+	{ "add", "args", 2, 0, 0, ARG_MAGIC|SHELL_ADD, shell_cf,
+		"( OLcfgDbAt:10.7 NAME 'olcShellAdd' "
+			"DESC 'Add command and arguments' "
+			"EQUALITY caseExactMatch "
+			"SYNTAX OMsDirectoryString SINGLE-VALUE ) ", NULL, NULL },
+	{ "delete", "args", 2, 0, 0, ARG_MAGIC|SHELL_DELETE, shell_cf,
+		"( OLcfgDbAt:10.8 NAME 'olcShellDelete' "
+			"DESC 'Delete command and arguments' "
+			"EQUALITY caseExactMatch "
+			"SYNTAX OMsDirectoryString SINGLE-VALUE ) ", NULL, NULL },
+	{ NULL }
+};
+
+static ConfigOCs shellocs[] = {
+	{ "( OLcfgDbOc:10.1 "
+		"NAME 'olcShellConfig'  "
+		"DESC 'Shell backend configuration' "
+		"SUP olcDatabaseConfig "
+		"MAY ( olcShellBind $ olcShellUnbind $ olcShellSearch $ "
+			"olcShellCompare $ olcShellModify $ olcShellModRDN $ "
+			"olcShellAdd $ olcShellDelete ) )",
+				Cft_Database, shellcfg },
+	{ NULL }
+};
+
+static int
+shell_cf( ConfigArgs *c )
+{
+	struct shellinfo	*si = (struct shellinfo *) c->be->be_private;
+	char ***arr = &si->si_bind;
+
+	if ( c->op == SLAP_CONFIG_EMIT ) {
+		struct berval bv;
+		if ( !arr[c->type] ) return 1;
+		bv.bv_val = ldap_charray2str( arr[c->type], " " );
+		bv.bv_len = strlen( bv.bv_val );
+		ber_bvarray_add( &c->rvalue_vals, &bv );
+	} else if ( c->op == LDAP_MOD_DELETE ) {
+		ldap_charray_free( arr[c->type] );
+		arr[c->type] = NULL;
+	} else {
+		arr[c->type] = ldap_charray_dup( &c->argv[1] );
+	}
+	return 0;
+}
+
+int
+shell_back_init_cf( BackendInfo *bi )
+{
+	bi->bi_cf_ocs = shellocs;
+	return config_register_schema( shellcfg, shellocs );
+}
diff --git a/servers/slapd/back-shell/delete.c b/servers/slapd/back-shell/delete.c
new file mode 100644
index 0000000..bb2f317
--- /dev/null
+++ b/servers/slapd/back-shell/delete.c
@@ -0,0 +1,90 @@
+/* delete.c - shell backend delete function */
+/* $OpenLDAP$ */
+/* 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>.
+ */
+/* Portions Copyright (c) 1995 Regents of the University of Michigan.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that this notice is preserved and that due credit is given
+ * to the University of Michigan at Ann Arbor. The name of the University
+ * may not be used to endorse or promote products derived from this
+ * software without specific prior written permission. This software
+ * is provided ``as is'' without express or implied warranty.
+ */
+/* ACKNOWLEDGEMENTS:
+ * This work was originally developed by the University of Michigan
+ * (as part of U-MICH LDAP).
+ */
+
+#include "portable.h"
+
+#include <stdio.h>
+
+#include <ac/string.h>
+#include <ac/socket.h>
+
+#include "slap.h"
+#include "shell.h"
+
+int
+shell_back_delete(
+    Operation	*op,
+    SlapReply	*rs )
+{
+	struct shellinfo	*si = (struct shellinfo *) op->o_bd->be_private;
+	AttributeDescription *entry = slap_schema.si_ad_entry;
+	Entry e;
+	FILE			*rfp, *wfp;
+
+	if ( si->si_delete == NULL ) {
+		send_ldap_error( op, rs, LDAP_UNWILLING_TO_PERFORM,
+		    "delete not implemented" );
+		return( -1 );
+	}
+
+	e.e_id = NOID;
+	e.e_name = op->o_req_dn;
+	e.e_nname = op->o_req_ndn;
+	e.e_attrs = NULL;
+	e.e_ocflags = 0;
+	e.e_bv.bv_len = 0;
+	e.e_bv.bv_val = NULL;
+	e.e_private = NULL;
+
+	if ( ! access_allowed( op, &e,
+		entry, NULL, ACL_WDEL, NULL ) )
+	{
+		send_ldap_error( op, rs, LDAP_INSUFFICIENT_ACCESS, NULL );
+		return -1;
+	}
+
+	if ( forkandexec( si->si_delete, &rfp, &wfp ) == (pid_t)-1 ) {
+		send_ldap_error( op, rs, LDAP_OTHER,
+		    "could not fork/exec" );
+		return( -1 );
+	}
+
+	/* write out the request to the delete process */
+	fprintf( wfp, "DELETE\n" );
+	fprintf( wfp, "msgid: %ld\n", (long) op->o_msgid );
+	print_suffixes( wfp, op->o_bd );
+	fprintf( wfp, "dn: %s\n", op->o_req_dn.bv_val );
+	fclose( wfp );
+
+	/* read in the results and send them along */
+	read_and_send_results( op, rs, rfp );
+	fclose( rfp );
+	return( 0 );
+}
diff --git a/servers/slapd/back-shell/fork.c b/servers/slapd/back-shell/fork.c
new file mode 100644
index 0000000..54100f7
--- /dev/null
+++ b/servers/slapd/back-shell/fork.c
@@ -0,0 +1,118 @@
+/* fork.c - fork and exec a process, connecting stdin/out w/pipes */
+/* $OpenLDAP$ */
+/* 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>.
+ */
+/* Portions Copyright (c) 1995 Regents of the University of Michigan.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that this notice is preserved and that due credit is given
+ * to the University of Michigan at Ann Arbor. The name of the University
+ * may not be used to endorse or promote products derived from this
+ * software without specific prior written permission. This software
+ * is provided ``as is'' without express or implied warranty.
+ */
+/* ACKNOWLEDGEMENTS:
+ * This work was originally developed by the University of Michigan
+ * (as part of U-MICH LDAP).
+ */
+
+#include "portable.h"
+
+#include <stdio.h>
+
+#include <ac/errno.h>
+#include <ac/string.h>
+#include <ac/socket.h>
+#include <ac/unistd.h>
+
+#include "slap.h"
+#include "shell.h"
+
+pid_t
+forkandexec(
+    char	**args,
+    FILE	**rfp,
+    FILE	**wfp
+)
+{
+	int	p2c[2] = { -1, -1 }, c2p[2];
+	pid_t	pid;
+
+	if ( pipe( p2c ) != 0 || pipe( c2p ) != 0 ) {
+		Debug( LDAP_DEBUG_ANY, "pipe failed\n", 0, 0, 0 );
+		close( p2c[0] );
+		close( p2c[1] );
+		return( -1 );
+	}
+
+	/*
+	 * what we're trying to set up looks like this:
+	 *	parent *wfp -> p2c[1] | p2c[0] -> stdin child
+	 *	parent *rfp <- c2p[0] | c2p[1] <- stdout child
+	 */
+
+	fflush( NULL );
+# ifdef HAVE_THR
+	pid = fork1();
+# else
+	pid = fork();
+# endif
+	if ( pid == 0 ) {		/* child */
+		/*
+		 * child could deadlock here due to resources locked
+		 * by our parent
+		 *
+		 * If so, configure --without-threads.
+		 */
+		if ( dup2( p2c[0], 0 ) == -1 || dup2( c2p[1], 1 ) == -1 ) {
+			Debug( LDAP_DEBUG_ANY, "dup2 failed\n", 0, 0, 0 );
+			exit( EXIT_FAILURE );
+		}
+	}
+	close( p2c[0] );
+	close( c2p[1] );
+	if ( pid <= 0 ) {
+		close( p2c[1] );
+		close( c2p[0] );
+	}
+	switch ( pid ) {
+	case 0:
+		execv( args[0], args );
+
+		Debug( LDAP_DEBUG_ANY, "execv failed\n", 0, 0, 0 );
+		exit( EXIT_FAILURE );
+
+	case -1:	/* trouble */
+		Debug( LDAP_DEBUG_ANY, "fork failed\n", 0, 0, 0 );
+		return( -1 );
+	}
+
+	/* parent */
+	if ( (*rfp = fdopen( c2p[0], "r" )) == NULL || (*wfp = fdopen( p2c[1],
+	    "w" )) == NULL ) {
+		Debug( LDAP_DEBUG_ANY, "fdopen failed\n", 0, 0, 0 );
+		if ( *rfp ) {
+			fclose( *rfp );
+			*rfp = NULL;
+		} else {
+			close( c2p[0] );
+		}
+		close( p2c[1] );
+
+		return( -1 );
+	}
+
+	return( pid );
+}
diff --git a/servers/slapd/back-shell/init.c b/servers/slapd/back-shell/init.c
new file mode 100644
index 0000000..e60cd6e
--- /dev/null
+++ b/servers/slapd/back-shell/init.c
@@ -0,0 +1,111 @@
+/* init.c - initialize shell backend */
+/* $OpenLDAP$ */
+/* 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>.
+ */
+/* Portions Copyright (c) 1995 Regents of the University of Michigan.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that this notice is preserved and that due credit is given
+ * to the University of Michigan at Ann Arbor. The name of the University
+ * may not be used to endorse or promote products derived from this
+ * software without specific prior written permission. This software
+ * is provided ``as is'' without express or implied warranty.
+ */
+/* ACKNOWLEDGEMENTS:
+ * This work was originally developed by the University of Michigan
+ * (as part of U-MICH LDAP).
+ */
+
+#include "portable.h"
+
+#include <stdio.h>
+
+#include <ac/socket.h>
+
+#include "slap.h"
+
+#include "config.h"
+
+#include "shell.h"
+
+int
+shell_back_initialize(
+    BackendInfo	*bi
+)
+{
+	bi->bi_open = 0;
+	bi->bi_config = 0;
+	bi->bi_close = 0;
+	bi->bi_destroy = 0;
+
+	bi->bi_db_init = shell_back_db_init;
+	bi->bi_db_config = 0;
+	bi->bi_db_open = 0;
+	bi->bi_db_close = 0;
+	bi->bi_db_destroy = shell_back_db_destroy;
+
+	bi->bi_op_bind = shell_back_bind;
+	bi->bi_op_unbind = shell_back_unbind;
+	bi->bi_op_search = shell_back_search;
+	bi->bi_op_compare = shell_back_compare;
+	bi->bi_op_modify = shell_back_modify;
+	bi->bi_op_modrdn = shell_back_modrdn;
+	bi->bi_op_add = shell_back_add;
+	bi->bi_op_delete = shell_back_delete;
+	bi->bi_op_abandon = 0;
+
+	bi->bi_extended = 0;
+
+	bi->bi_chk_referrals = 0;
+
+	bi->bi_connection_init = 0;
+	bi->bi_connection_destroy = 0;
+
+	return shell_back_init_cf( bi );
+}
+
+int
+shell_back_db_init(
+	Backend	*be,
+	ConfigReply *cr
+)
+{
+	struct shellinfo	*si;
+
+	si = (struct shellinfo *) ch_calloc( 1, sizeof(struct shellinfo) );
+
+	be->be_private = si;
+	be->be_cf_ocs = be->bd_info->bi_cf_ocs;
+
+	return si == NULL;
+}
+
+int
+shell_back_db_destroy(
+	Backend	*be,
+	ConfigReply *cr
+)
+{
+	free( be->be_private );
+	return 0;
+}
+
+#if SLAPD_SHELL == SLAPD_MOD_DYNAMIC
+
+/* conditionally define the init_module() function */
+SLAP_BACKEND_INIT_MODULE( shell )
+
+#endif /* SLAPD_SHELL == SLAPD_MOD_DYNAMIC */
+
diff --git a/servers/slapd/back-shell/modify.c b/servers/slapd/back-shell/modify.c
new file mode 100644
index 0000000..8ddb674
--- /dev/null
+++ b/servers/slapd/back-shell/modify.c
@@ -0,0 +1,126 @@
+/* modify.c - shell backend modify function */
+/* $OpenLDAP$ */
+/* 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>.
+ */
+/* Portions Copyright (c) 1995 Regents of the University of Michigan.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that this notice is preserved and that due credit is given
+ * to the University of Michigan at Ann Arbor. The name of the University
+ * may not be used to endorse or promote products derived from this
+ * software without specific prior written permission. This software
+ * is provided ``as is'' without express or implied warranty.
+ */
+/* ACKNOWLEDGEMENTS:
+ * This work was originally developed by the University of Michigan
+ * (as part of U-MICH LDAP).
+ */
+
+#include "portable.h"
+
+#include <stdio.h>
+
+#include <ac/string.h>
+#include <ac/socket.h>
+
+#include "slap.h"
+#include "shell.h"
+#include "ldif.h"
+
+int
+shell_back_modify(
+    Operation	*op,
+    SlapReply	*rs )
+{
+	Modification *mod;
+	struct shellinfo	*si = (struct shellinfo *) op->o_bd->be_private;
+	AttributeDescription *entry = slap_schema.si_ad_entry;
+	Modifications *ml  = op->orm_modlist;
+	Entry e;
+	FILE			*rfp, *wfp;
+	int			i;
+
+	if ( si->si_modify == NULL ) {
+		send_ldap_error( op, rs, LDAP_UNWILLING_TO_PERFORM,
+		    "modify not implemented" );
+		return( -1 );
+	}
+
+	e.e_id = NOID;
+	e.e_name = op->o_req_dn;
+	e.e_nname = op->o_req_ndn;
+	e.e_attrs = NULL;
+	e.e_ocflags = 0;
+	e.e_bv.bv_len = 0;
+	e.e_bv.bv_val = NULL;
+	e.e_private = NULL;
+
+	if ( ! access_allowed( op, &e,
+		entry, NULL, ACL_WRITE, NULL ) )
+	{
+		send_ldap_error( op, rs, LDAP_INSUFFICIENT_ACCESS, NULL );
+		return -1;
+	}
+
+	if ( forkandexec( si->si_modify, &rfp, &wfp ) == (pid_t)-1 ) {
+		send_ldap_error( op, rs, LDAP_OTHER,
+		    "could not fork/exec" );
+		return( -1 );
+	}
+
+	/* write out the request to the modify process */
+	fprintf( wfp, "MODIFY\n" );
+	fprintf( wfp, "msgid: %ld\n", (long) op->o_msgid );
+	print_suffixes( wfp, op->o_bd );
+	fprintf( wfp, "dn: %s\n", op->o_req_dn.bv_val );
+	for ( ; ml != NULL; ml = ml->sml_next ) {
+		mod = &ml->sml_mod;
+
+		switch ( mod->sm_op ) {
+		case LDAP_MOD_ADD:
+			fprintf( wfp, "add: %s\n", mod->sm_desc->ad_cname.bv_val );
+			break;
+
+		case LDAP_MOD_DELETE:
+			fprintf( wfp, "delete: %s\n", mod->sm_desc->ad_cname.bv_val );
+			break;
+
+		case LDAP_MOD_REPLACE:
+			fprintf( wfp, "replace: %s\n", mod->sm_desc->ad_cname.bv_val );
+			break;
+		}
+
+		if( mod->sm_values != NULL ) {
+			for ( i = 0; mod->sm_values[i].bv_val != NULL; i++ ) {
+				char *out = ldif_put( LDIF_PUT_VALUE,
+					mod->sm_desc->ad_cname.bv_val,
+					mod->sm_values[i].bv_val,
+					mod->sm_values[i].bv_len );
+				if ( out ) {
+					fprintf( wfp, "%s", out );
+					ber_memfree( out );
+				}
+			}
+		}
+
+		fprintf( wfp, "-\n" );
+	}
+	fclose( wfp );
+
+	/* read in the results and send them along */
+	read_and_send_results( op, rs, rfp );
+	fclose( rfp );
+	return( 0 );
+}
diff --git a/servers/slapd/back-shell/modrdn.c b/servers/slapd/back-shell/modrdn.c
new file mode 100644
index 0000000..7c56fa5
--- /dev/null
+++ b/servers/slapd/back-shell/modrdn.c
@@ -0,0 +1,96 @@
+/* modrdn.c - shell backend modrdn function */
+/* $OpenLDAP$ */
+/* 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>.
+ */
+/* Portions Copyright (c) 1995 Regents of the University of Michigan.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that this notice is preserved and that due credit is given
+ * to the University of Michigan at Ann Arbor. The name of the University
+ * may not be used to endorse or promote products derived from this
+ * software without specific prior written permission. This software
+ * is provided ``as is'' without express or implied warranty.
+ */
+/* ACKNOWLEDGEMENTS:
+ * This work was originally developed by the University of Michigan
+ * (as part of U-MICH LDAP).
+ */
+
+#include "portable.h"
+
+#include <stdio.h>
+
+#include <ac/socket.h>
+#include <ac/string.h>
+
+#include "slap.h"
+#include "shell.h"
+
+int
+shell_back_modrdn(
+    Operation	*op,
+    SlapReply	*rs )
+{
+	struct shellinfo	*si = (struct shellinfo *) op->o_bd->be_private;
+	AttributeDescription *entry = slap_schema.si_ad_entry;
+	Entry e;
+	FILE			*rfp, *wfp;
+
+	if ( si->si_modrdn == NULL ) {
+		send_ldap_error( op, rs, LDAP_UNWILLING_TO_PERFORM,
+		    "modrdn not implemented" );
+		return( -1 );
+	}
+
+	e.e_id = NOID;
+	e.e_name = op->o_req_dn;
+	e.e_nname = op->o_req_ndn;
+	e.e_attrs = NULL;
+	e.e_ocflags = 0;
+	e.e_bv.bv_len = 0;
+	e.e_bv.bv_val = NULL;
+	e.e_private = NULL;
+
+	if ( ! access_allowed( op, &e, entry, NULL,
+			op->oq_modrdn.rs_newSup ? ACL_WDEL : ACL_WRITE,
+			NULL ) )
+	{
+		send_ldap_error( op, rs, LDAP_INSUFFICIENT_ACCESS, NULL );
+		return -1;
+	}
+
+	if ( forkandexec( si->si_modrdn, &rfp, &wfp ) == (pid_t)-1 ) {
+		send_ldap_error( op, rs, LDAP_OTHER,
+		    "could not fork/exec" );
+		return( -1 );
+	}
+
+	/* write out the request to the modrdn process */
+	fprintf( wfp, "MODRDN\n" );
+	fprintf( wfp, "msgid: %ld\n", (long) op->o_msgid );
+	print_suffixes( wfp, op->o_bd );
+	fprintf( wfp, "dn: %s\n", op->o_req_dn.bv_val );
+	fprintf( wfp, "newrdn: %s\n", op->oq_modrdn.rs_newrdn.bv_val );
+	fprintf( wfp, "deleteoldrdn: %d\n", op->oq_modrdn.rs_deleteoldrdn ? 1 : 0 );
+	if ( op->oq_modrdn.rs_newSup != NULL ) {
+		fprintf( wfp, "newSuperior: %s\n", op->oq_modrdn.rs_newSup->bv_val );
+	}
+	fclose( wfp );
+
+	/* read in the results and send them along */
+	read_and_send_results( op, rs, rfp );
+	fclose( rfp );
+	return( 0 );
+}
diff --git a/servers/slapd/back-shell/proto-shell.h b/servers/slapd/back-shell/proto-shell.h
new file mode 100644
index 0000000..f6a9aad
--- /dev/null
+++ b/servers/slapd/back-shell/proto-shell.h
@@ -0,0 +1,56 @@
+/* $OpenLDAP$ */
+/* 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>.
+ */
+/* Portions Copyright (c) 1995 Regents of the University of Michigan.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that this notice is preserved and that due credit is given
+ * to the University of Michigan at Ann Arbor. The name of the University
+ * may not be used to endorse or promote products derived from this
+ * software without specific prior written permission. This software
+ * is provided ``as is'' without express or implied warranty.
+ */
+/* ACKNOWLEDGEMENTS:
+ * This work was originally developed by the University of Michigan
+ * (as part of U-MICH LDAP).
+ */
+
+#ifndef PROTO_SHELL_H
+#define PROTO_SHELL_H
+
+LDAP_BEGIN_DECL
+
+extern BI_init		shell_back_initialize;
+
+extern BI_open		shell_back_open;
+extern BI_close		shell_back_close;
+extern BI_destroy	shell_back_destroy;
+
+extern BI_db_init	shell_back_db_init;
+extern BI_db_destroy	shell_back_db_destroy;
+
+extern BI_op_bind	shell_back_bind;
+extern BI_op_unbind	shell_back_unbind;
+extern BI_op_search	shell_back_search;
+extern BI_op_compare	shell_back_compare;
+extern BI_op_modify	shell_back_modify;
+extern BI_op_modrdn	shell_back_modrdn;
+extern BI_op_add	shell_back_add;
+extern BI_op_delete	shell_back_delete;
+
+extern int shell_back_init_cf( BackendInfo *bi );
+LDAP_END_DECL
+
+#endif /* PROTO_SHELL_H */
diff --git a/servers/slapd/back-shell/result.c b/servers/slapd/back-shell/result.c
new file mode 100644
index 0000000..9133eaf
--- /dev/null
+++ b/servers/slapd/back-shell/result.c
@@ -0,0 +1,135 @@
+/* result.c - shell backend result reading function */
+/* $OpenLDAP$ */
+/* 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>.
+ */
+/* Portions Copyright (c) 1995 Regents of the University of Michigan.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that this notice is preserved and that due credit is given
+ * to the University of Michigan at Ann Arbor. The name of the University
+ * may not be used to endorse or promote products derived from this
+ * software without specific prior written permission. This software
+ * is provided ``as is'' without express or implied warranty.
+ */
+/* ACKNOWLEDGEMENTS:
+ * This work was originally developed by the University of Michigan
+ * (as part of U-MICH LDAP).
+ */
+
+#include "portable.h"
+
+#include <stdio.h>
+
+#include <ac/errno.h>
+#include <ac/string.h>
+#include <ac/socket.h>
+#include <ac/unistd.h>
+
+#include "slap.h"
+#include "shell.h"
+
+int
+read_and_send_results(
+    Operation	*op,
+    SlapReply	*rs,
+    FILE	*fp )
+{
+	int	bsize, len;
+	char	*buf, *bp;
+	char	line[BUFSIZ];
+	char	ebuf[128];
+
+	/* read in the result and send it along */
+	buf = (char *) ch_malloc( BUFSIZ );
+	buf[0] = '\0';
+	bsize = BUFSIZ;
+	bp = buf;
+	while ( !feof(fp) ) {
+		errno = 0;
+		if ( fgets( line, sizeof(line), fp ) == NULL ) {
+			if ( errno == EINTR ) continue;
+
+			Debug( LDAP_DEBUG_ANY, "shell: fgets failed: %s (%d)\n",
+				AC_STRERROR_R(errno, ebuf, sizeof ebuf), errno, 0 ); 
+			break;
+		}
+
+		Debug( LDAP_DEBUG_SHELL, "shell search reading line (%s)\n",
+		    line, 0, 0 );
+
+		/* ignore lines beginning with # (LDIFv1 comments) */
+		if ( *line == '#' ) {
+			continue;
+		}
+
+		/* ignore lines beginning with DEBUG: */
+		if ( strncasecmp( line, "DEBUG:", 6 ) == 0 ) {
+			continue;
+		}
+
+		len = strlen( line );
+		while ( bp + len + 1 - buf > bsize ) {
+			size_t offset = bp - buf;
+			bsize += BUFSIZ;
+			buf = (char *) ch_realloc( buf, bsize );
+			bp = &buf[offset];
+		}
+		strcpy( bp, line );
+		bp += len;
+
+		/* line marked the end of an entry or result */
+		if ( *line == '\n' ) {
+			if ( strncasecmp( buf, "RESULT", 6 ) == 0 ) {
+				break;
+			}
+
+			if ( (rs->sr_entry = str2entry( buf )) == NULL ) {
+				Debug( LDAP_DEBUG_ANY, "str2entry(%s) failed\n",
+				    buf, 0, 0 );
+			} else {
+				rs->sr_attrs = op->oq_search.rs_attrs;
+				rs->sr_flags = REP_ENTRY_MODIFIABLE;
+				send_search_entry( op, rs );
+				entry_free( rs->sr_entry );
+				rs->sr_attrs = NULL;
+			}
+
+			bp = buf;
+		}
+	}
+	(void) str2result( buf, &rs->sr_err, (char **)&rs->sr_matched, (char **)&rs->sr_text );
+
+	/* otherwise, front end will send this result */
+	if ( rs->sr_err != 0 || op->o_tag != LDAP_REQ_BIND ) {
+		send_ldap_result( op, rs );
+	}
+
+	free( buf );
+
+	return( rs->sr_err );
+}
+
+void
+print_suffixes(
+    FILE	*fp,
+    Backend	*be
+)
+{
+	int	i;
+
+	for ( i = 0; be->be_suffix[i].bv_val != NULL; i++ ) {
+		fprintf( fp, "suffix: %s\n", be->be_suffix[i].bv_val );
+	}
+}
diff --git a/servers/slapd/back-shell/search.c b/servers/slapd/back-shell/search.c
new file mode 100644
index 0000000..b628b9f
--- /dev/null
+++ b/servers/slapd/back-shell/search.c
@@ -0,0 +1,86 @@
+/* search.c - shell backend search function */
+/* $OpenLDAP$ */
+/* 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>.
+ */
+/* Portions Copyright (c) 1995 Regents of the University of Michigan.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that this notice is preserved and that due credit is given
+ * to the University of Michigan at Ann Arbor. The name of the University
+ * may not be used to endorse or promote products derived from this
+ * software without specific prior written permission. This software
+ * is provided ``as is'' without express or implied warranty.
+ */
+/* ACKNOWLEDGEMENTS:
+ * This work was originally developed by the University of Michigan
+ * (as part of U-MICH LDAP).
+ */
+
+#include "portable.h"
+
+#include <stdio.h>
+
+#include <ac/socket.h>
+#include <ac/string.h>
+
+#include "slap.h"
+#include "shell.h"
+
+int
+shell_back_search(
+    Operation	*op,
+    SlapReply	*rs )
+{
+	struct shellinfo	*si = (struct shellinfo *) op->o_bd->be_private;
+	FILE			*rfp, *wfp;
+	AttributeName		*an;
+
+	if ( si->si_search == NULL ) {
+		send_ldap_error( op, rs, LDAP_UNWILLING_TO_PERFORM,
+		    "search not implemented" );
+		return( -1 );
+	}
+
+	if ( forkandexec( si->si_search, &rfp, &wfp ) == (pid_t)-1 ) {
+		send_ldap_error( op, rs, LDAP_OTHER,
+		    "could not fork/exec" );
+		return( -1 );
+	}
+
+	/* write out the request to the search process */
+	fprintf( wfp, "SEARCH\n" );
+	fprintf( wfp, "msgid: %ld\n", (long) op->o_msgid );
+	print_suffixes( wfp, op->o_bd );
+	fprintf( wfp, "base: %s\n", op->o_req_dn.bv_val );
+	fprintf( wfp, "scope: %d\n", op->oq_search.rs_scope );
+	fprintf( wfp, "deref: %d\n", op->oq_search.rs_deref );
+	fprintf( wfp, "sizelimit: %d\n", op->oq_search.rs_slimit );
+	fprintf( wfp, "timelimit: %d\n", op->oq_search.rs_tlimit );
+	fprintf( wfp, "filter: %s\n", op->oq_search.rs_filterstr.bv_val );
+	fprintf( wfp, "attrsonly: %d\n", op->oq_search.rs_attrsonly ? 1 : 0 );
+	fprintf( wfp, "attrs:%s", op->oq_search.rs_attrs == NULL ? " all" : "" );
+	for ( an = op->oq_search.rs_attrs; an && an->an_name.bv_val; an++ ) {
+		fprintf( wfp, " %s", an->an_name.bv_val );
+	}
+	fprintf( wfp, "\n" );
+	fclose( wfp );
+
+	/* read in the results and send them along */
+	rs->sr_attrs = op->oq_search.rs_attrs;
+	read_and_send_results( op, rs, rfp );
+
+	fclose( rfp );
+	return( 0 );
+}
diff --git a/servers/slapd/back-shell/searchexample.conf b/servers/slapd/back-shell/searchexample.conf
new file mode 100644
index 0000000..a450ad3
--- /dev/null
+++ b/servers/slapd/back-shell/searchexample.conf
@@ -0,0 +1,29 @@
+# $OpenLDAP$
+## 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>.
+#
+## Portions Copyright (c) 1995 Regents of the University of Michigan.
+## All rights reserved.
+##
+## Redistribution and use in source and binary forms are permitted
+## provided that this notice is preserved and that due credit is given
+## to the University of Michigan at Ann Arbor. The name of the University
+## may not be used to endorse or promote products derived from this
+## software without specific prior written permission. This software
+## is provided ``as is'' without express or implied warranty.
+
+include		/usr/local/etc/openldap/schema/core.schema
+
+database	shell
+suffix		"dc=example,dc=com"
+search		/usr/local/etc/searchexample.sh
diff --git a/servers/slapd/back-shell/searchexample.sh b/servers/slapd/back-shell/searchexample.sh
new file mode 100644
index 0000000..9ded406
--- /dev/null
+++ b/servers/slapd/back-shell/searchexample.sh
@@ -0,0 +1,65 @@
+#! /bin/sh
+# $OpenLDAP$
+## 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>.
+#
+## Portions Copyright (c) 1995 Regents of the University of Michigan.
+## All rights reserved.
+##
+## Redistribution and use in source and binary forms are permitted
+## provided that this notice is preserved and that due credit is given
+## to the University of Michigan at Ann Arbor. The name of the University
+## may not be used to endorse or promote products derived from this
+## software without specific prior written permission. This software
+## is provided ``as is'' without express or implied warranty.
+
+while [ 1 ]; do
+	read TAG VALUE
+	if [ $? -ne 0 ]; then
+		break
+	fi
+	case "$TAG" in
+		base:)
+		BASE=$VALUE
+		;;
+		filter:)
+		FILTER=$VALUE
+		;;
+		# include other parameters here
+	esac
+done
+
+LOGIN=`echo $FILTER | sed -e 's/.*=\(.*\))/\1/'`
+
+PWLINE=`grep -i "^$LOGIN" /etc/passwd`
+
+#sleep 60
+# if we found an entry that matches
+if [ $? = 0 ]; then
+	echo $PWLINE | awk -F: '{
+		printf("dn: cn=%s,%s\n", $1, base);
+		printf("objectclass: top\n");
+		printf("objectclass: person\n");
+		printf("cn: %s\n", $1);
+		printf("cn: %s\n", $5);
+		printf("sn: %s\n", $1);
+		printf("uid: %s\n", $1);
+	}' base="$BASE"
+	echo ""
+fi
+
+# result
+echo "RESULT"
+echo "code: 0"
+
+exit 0
diff --git a/servers/slapd/back-shell/shell.h b/servers/slapd/back-shell/shell.h
new file mode 100644
index 0000000..ec239b3
--- /dev/null
+++ b/servers/slapd/back-shell/shell.h
@@ -0,0 +1,65 @@
+/* shell.h - shell backend header file */
+/* $OpenLDAP$ */
+/* 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>.
+ */
+/* Portions Copyright (c) 1995 Regents of the University of Michigan.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that this notice is preserved and that due credit is given
+ * to the University of Michigan at Ann Arbor. The name of the University
+ * may not be used to endorse or promote products derived from this
+ * software without specific prior written permission. This software
+ * is provided ``as is'' without express or implied warranty.
+ */
+/* ACKNOWLEDGEMENTS:
+ * This work was originally developed by the University of Michigan
+ * (as part of U-MICH LDAP).
+ */
+
+#ifndef SLAPD_SHELL_H
+#define SLAPD_SHELL_H
+
+#include "proto-shell.h"
+
+LDAP_BEGIN_DECL
+
+struct shellinfo {
+	char	**si_bind;		/* cmd + args to exec for bind	  */
+	char	**si_unbind;	/* cmd + args to exec for unbind  */
+	char	**si_search;	/* cmd + args to exec for search  */
+	char	**si_compare;	/* cmd + args to exec for compare */
+	char	**si_modify;	/* cmd + args to exec for modify  */
+	char	**si_modrdn;	/* cmd + args to exec for modrdn  */
+	char	**si_add;		/* cmd + args to exec for add	  */
+	char	**si_delete;	/* cmd + args to exec for delete  */
+};
+
+extern pid_t forkandexec LDAP_P((
+	char **args,
+	FILE **rfp,
+	FILE **wfp));
+
+extern void print_suffixes LDAP_P((
+	FILE *fp,
+	BackendDB *bd));
+
+extern int read_and_send_results LDAP_P((
+	Operation *op,
+	SlapReply *rs,
+	FILE *fp));
+
+LDAP_END_DECL
+
+#endif
diff --git a/servers/slapd/back-shell/unbind.c b/servers/slapd/back-shell/unbind.c
new file mode 100644
index 0000000..77016e2
--- /dev/null
+++ b/servers/slapd/back-shell/unbind.c
@@ -0,0 +1,69 @@
+/* unbind.c - shell backend unbind function */
+/* $OpenLDAP$ */
+/* 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>.
+ */
+/* Portions Copyright (c) 1995 Regents of the University of Michigan.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that this notice is preserved and that due credit is given
+ * to the University of Michigan at Ann Arbor. The name of the University
+ * may not be used to endorse or promote products derived from this
+ * software without specific prior written permission. This software
+ * is provided ``as is'' without express or implied warranty.
+ */
+/* ACKNOWLEDGEMENTS:
+ * This work was originally developed by the University of Michigan
+ * (as part of U-MICH LDAP).
+ */
+
+#include "portable.h"
+
+#include <stdio.h>
+
+#include <ac/socket.h>
+#include <ac/string.h>
+
+#include "slap.h"
+#include "shell.h"
+
+int
+shell_back_unbind(
+    Operation		*op,
+    SlapReply		*rs
+)
+{
+	struct shellinfo	*si = (struct shellinfo *) op->o_bd->be_private;
+	FILE			*rfp, *wfp;
+
+	if ( si->si_unbind == NULL ) {
+		return 0;
+	}
+
+	if ( forkandexec( si->si_unbind, &rfp, &wfp ) == (pid_t)-1 ) {
+		return 0;
+	}
+
+	/* write out the request to the unbind process */
+	fprintf( wfp, "UNBIND\n" );
+	fprintf( wfp, "msgid: %ld\n", (long) op->o_msgid );
+	print_suffixes( wfp, op->o_bd );
+	fprintf( wfp, "dn: %s\n", (op->o_conn->c_dn.bv_len ? op->o_conn->c_dn.bv_val : "") );
+	fclose( wfp );
+
+	/* no response to unbind */
+	fclose( rfp );
+
+	return 0;
+}