/*

 * CDDL HEADER START

 *

 * The contents of this file are subject to the terms of the

 * Common Development and Distribution License, Version 1.0 only

 * (the "License").  You may not use this file except in compliance

 * with the License.

 *

 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE

 * or http://www.opensolaris.org/os/licensing.

 * See the License for the specific language governing permissions

 * and limitations under the License.

 *

 * When distributing Covered Code, include this CDDL HEADER in each

 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.

 * If applicable, add the following below this CDDL HEADER, with the

 * fields enclosed by brackets "[]" replaced with your own identifying

 * information: Portions Copyright [yyyy] [name of copyright owner]

 *

 * CDDL HEADER END

 */

/*

 * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.

 * Use is subject to license terms.

 */

#pragma ident	"%Z%%M%	%I%	%E% SMI"

#include "synonyms.h"

#include <mtlib.h>

#include <sys/types.h>

#include <pwd.h>

#include <nss_dbdefs.h>

#include <stdio.h>

#include <synch.h>

#include <sys/param.h>

#include <fcntl.h>

#include <unistd.h>

#include <getxby_door.h>

#include <sys/door.h>

#include "libc.h"

#include "base_conversion.h"

/*

 *

 * Routine that actually performs the door call.

 * Note that we cache a file descriptor.  We do

 * the following to prevent disasters:

 *

 * 1) Never use 0,1 or 2; if we get this from the open

 *    we dup it upwards.

 *

 * 2) Set the close on exec flags so descriptor remains available

 *    to child processes.

 *

 * 3) Verify that the door is still the same one we had before

 *    by using door_info on the client side.

 *

 *	Note that we never close the file descriptor if it isn't one

 *	we allocated; we check this with door info.  The rather tricky

 *	logic is designed to be fast in the normal case (fd is already

 *	allocated and is ok) while handling the case where the application

 *	closed it underneath us or where the nscd dies or re-execs itself

 *	and we're a multi-threaded application.  Note that we cannot protect

 *	the application if it closes the fd and it is multi-threaded.

 *

 *  int _nsc_trydoorcall(void *dptr, int *bufsize, int *actualsize);

 *

 *      *dptr           IN: points to arg buffer OUT: points to results buffer

 *      *bufsize        IN: overall size of buffer OUT: overall size of buffer

 *      *actualsize     IN: size of call data OUT: size of return data

 *

 *  Note that *dptr may change if provided space as defined by *bufsize is

 *  inadequate.  In this case the door call mmaps more space and places

 *  the answer there and sets dptr to contain a pointer to the space, which

 *  should be freed with munmap.

 *

 *  Returns 0 if the door call reached the server, -1 if contact was not made.

 *

 */

static mutex_t	_door_lock = DEFAULTMUTEX;

int

_nsc_trydoorcall(nsc_data_t **dptr, int *ndata, int *adata)

{

	static	int 		doorfd = -1;

	static	door_info_t 	real_door;

	door_info_t 		my_door;

	door_arg_t		param;

	/*

	 * the first time in we try and open and validate the door.

	 * the validations are that the door must have been

	 * created with the name service door cookie and

	 * that the file attached to the door is owned by root

	 * and readonly by user, group and other.  If any of these

	 * validations fail we refuse to use the door.

	 */

	lmutex_lock(&_door_lock);

try_again:

	if (doorfd == -1) {

		int		tbc[3];

		int		i;

		if ((doorfd = open64(NAME_SERVICE_DOOR, O_RDONLY, 0))

		    == -1) {

			lmutex_unlock(&_door_lock);

			return (NOSERVER);

		}

		/*

		 * dup up the file descriptor if we have 0 - 2

		 * to avoid problems with shells stdin/out/err

		 */

		i = 0;

		while (doorfd < 3) { /* we have a reserved fd */

			tbc[i++] = doorfd;

			if ((doorfd = dup(doorfd)) < 0) {

				while (i--)

				    (void) close(tbc[i]);

				doorfd = -1;

				lmutex_unlock(&_door_lock);

				return (NOSERVER);

			}

		}

		while (i--)

		    (void) close(tbc[i]);

		/*

		 * mark this door descriptor as close on exec

		 */

		(void) fcntl(doorfd, F_SETFD, FD_CLOEXEC);

		if (__door_info(doorfd, &real_door) == -1) {

			/*

			 * we should close doorfd because we just opened it

			 */

			(void) close(doorfd);

			doorfd = -1;

			lmutex_unlock(&_door_lock);

			return (NOSERVER);

		}

		if ((real_door.di_attributes & DOOR_REVOKED) ||

		    (real_door.di_data !=

		    (door_ptr_t)NAME_SERVICE_DOOR_COOKIE)) {

			(void) close(doorfd);

			doorfd = -1;

			lmutex_unlock(&_door_lock);

			return (NOSERVER);

		}

	} else {

		if ((__door_info(doorfd, &my_door) == -1) ||

		    (my_door.di_data != (door_ptr_t)NAME_SERVICE_DOOR_COOKIE) ||

			(my_door.di_uniquifier != real_door.di_uniquifier)) {

				/*

				 * don't close it -

				 * someone else has clobbered fd

				 */

				doorfd = -1;

				goto try_again;

			}

		if (my_door.di_attributes & DOOR_REVOKED) {

			(void) close(doorfd);	/* nscd exited .... */

			doorfd = -1;	/* try and restart connection */

			goto try_again;

		}

	}

	lmutex_unlock(&_door_lock);

	param.rbuf = (char *)*dptr;

	param.rsize = *ndata;

	param.data_ptr = (char *)*dptr;

	param.data_size = *adata;

	param.desc_ptr = NULL;

	param.desc_num = 0;

	if (__door_call(doorfd, &param) == -1) {

		return (NOSERVER);

	}

	*adata = (int)param.data_size;

	*ndata = (int)param.rsize;

	*dptr = (nsc_data_t *)(uintptr_t)param.data_ptr;

	if (*adata == 0 || *dptr == NULL) {

		return (NOSERVER);

	}

	return ((*dptr)->nsc_ret.nsc_return_code);

}