/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (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 2006 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <door.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <synch.h>
#include <time.h>
#include <unistd.h>

#include <sys/param.h>
#include <sys/stat.h>
#include <sys/types.h>

#include "labeld.h"

#ifndef DEBUG
#define perror(e)
#endif  /* !DEBUG */

/*
 *      This is cloned from _nsc_trydoorcall used by the nscd client.
 *
 * 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 __call_labeld(label_door_op **dptr, int *ndata, int *adata);
 *
 *      *dptr   IN: points to arg buffer OUT: points to results buffer
 *      *ndata  IN: overall size of buffer OUT: overall size of buffer
 *      *adata  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
__call_labeld(labeld_data_t **dptr, size_t *ndata, size_t *adata)
{
        static  int             doorfd = -1;
        static  door_info_t     real_door;
        struct stat             st;
        door_info_t             my_door;
        door_arg_t              param;
        char                    door_name[MAXPATHLEN];
        struct timespec         ts;
        int                     busy = 0;       /* number of busy loops */

#ifdef  DEBUG
        labeld_data_t           *callptr = *dptr;
        int                     buf_size = *ndata;
        int                     return_size = *adata;
#endif  /* DEBUG */

        /*
         * the first time in we try and open and validate the door.
         * the validations are that the door must have been
         * created with the label service door cookie and
         * that it has the same door ID.  If any of these
         * validations fail we refuse to use the door.
         */
        ts.tv_sec = 0;          /* initialize nanosecond retry timer */
        ts.tv_nsec = 100;
        (void) mutex_lock(&_door_lock);

try_again:
        if (doorfd == -1) {
                int     tbc[3];
                int     i;

                (void) snprintf(door_name, sizeof (door_name), "%s%s",
                    DOOR_PATH, DOOR_NAME);
                if ((doorfd = open64(door_name, O_RDONLY, 0)) < 0) {
                        (void) mutex_unlock(&_door_lock);
                        perror("server door open");
                        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) {
                                perror("couldn't dup");
                                while (i--)
                                        (void) close(tbc[i]);
                                doorfd = -1;
                                (void) mutex_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) < 0) {
                        /*
                         * we should close doorfd because we just opened it
                         */
                        perror("real door door_info");
                        (void) close(doorfd);
                        doorfd = -1;
                        (void) mutex_unlock(&_door_lock);
                        return (NOSERVER);
                }
                if (fstat(doorfd, &st) < 0) {
                        perror("real door fstat");
                        return (NOSERVER);
                }
#ifdef  DEBUG
                (void) printf("\treal door %s\n", door_name);
                (void) printf("\t\tuid = %d, gid = %d, mode = %o\n", st.st_uid,
                    st.st_gid, st.st_mode);
                (void) printf("\t\toutstanding requests = %d\n", st.st_nlink-1);
                (void) printf("\t\t pid = %d\n", real_door.di_target);
                (void) printf("\t\t procedure = %llx\n", real_door.di_proc);
                (void) printf("\t\t cookie = %llx\n",  real_door.di_data);
                (void) printf("\t\t attributes = %x\n",
                    real_door.di_attributes);
                if (real_door.di_attributes & DOOR_UNREF)
                        (void) printf("\t\t\t UNREF\n");
                if (real_door.di_attributes & DOOR_PRIVATE)
                        (void) printf("\t\t\t PRIVATE\n");
                if (real_door.di_attributes & DOOR_LOCAL)
                        (void) printf("\t\t\t LOCAL\n");
                if (real_door.di_attributes & DOOR_REVOKED)
                        (void) printf("\t\t\t REVOKED\n");
                if (real_door.di_attributes & DOOR_DESCRIPTOR)
                        (void) printf("\t\t\t DESCRIPTOR\n");
                if (real_door.di_attributes & DOOR_RELEASE)
                        (void) printf("\t\t\t RELEASE\n");
                if (real_door.di_attributes & DOOR_DELAY)
                        (void) printf("\t\t\t DELAY\n");
                (void) printf("\t\t id = %llx\n", real_door.di_uniquifier);
#endif  /* DEBUG */
                if ((real_door.di_attributes & DOOR_REVOKED) ||
                    (real_door.di_data != COOKIE)) {
#ifdef  DEBUG
                        (void) printf("real door revoked\n");
#endif  /* DEBUG */
                        (void) close(doorfd);
                        doorfd = -1;
                        (void) mutex_unlock(&_door_lock);
                        return (NOSERVER);
                }
        } else {
                if ((door_info(doorfd, &my_door) < 0) ||
                    (my_door.di_data != COOKIE) ||
                    (my_door.di_uniquifier != real_door.di_uniquifier)) {
                        perror("my door door_info");
                        /*
                         * don't close it - someone else has clobbered fd
                         */
                        doorfd = -1;
                        goto try_again;
                }
                if (fstat(doorfd, &st) < 0) {
                        perror("my door fstat");
                        goto try_again;
                }
#ifdef  DEBUG
                (void) sprintf(door_name, "%s%s", DOOR_PATH, DOOR_NAME);
                (void) printf("\tmy door %s\n", door_name);
                (void) printf("\t\tuid = %d, gid = %d, mode = %o\n", st.st_uid,
                    st.st_gid, st.st_mode);
                (void) printf("\t\toutstanding requests = %d\n", st.st_nlink-1);
                (void) printf("\t\t pid = %d\n", my_door.di_target);
                (void) printf("\t\t procedure = %llx\n", my_door.di_proc);
                (void) printf("\t\t cookie = %llx\n",  my_door.di_data);
                (void) printf("\t\t attributes = %x\n", my_door.di_attributes);
                if (my_door.di_attributes & DOOR_UNREF)
                        (void) printf("\t\t\t UNREF\n");
                if (my_door.di_attributes & DOOR_PRIVATE)
                        (void) printf("\t\t\t PRIVATE\n");
                if (my_door.di_attributes & DOOR_LOCAL)
                        (void) printf("\t\t\t LOCAL\n");
                if (my_door.di_attributes & DOOR_REVOKED)
                        (void) printf("\t\t\t REVOKED\n");
                if (my_door.di_attributes & DOOR_DESCRIPTOR)
                        (void) printf("\t\t\t DESCRIPTOR\n");
                if (my_door.di_attributes & DOOR_RELEASE)
                        (void) printf("\t\t\t RELEASE\n");
                if (my_door.di_attributes & DOOR_DELAY)
                        (void) printf("\t\t\t DELAY\n");
                (void) printf("\t\t id = %llx\n", my_door.di_uniquifier);
#endif  /* DEBUG */
                if (my_door.di_attributes & DOOR_REVOKED) {
#ifdef  DEBUG
                        (void) printf("my door revoked\n");
#endif  /* DEBUG */
                        (void) close(doorfd);   /* labeld exited .... */
                        doorfd = -1;    /* try and restart connection */
                        goto try_again;
                }
        }
        (void) mutex_unlock(&_door_lock);

        param.data_ptr = (char *)*dptr;
        param.data_size = *adata;
        param.desc_ptr = NULL;
        param.desc_num = 0;
        param.rbuf = (char *)*dptr;
        param.rsize = *ndata;

        if (door_call(doorfd, &param) < 0) {
                if (errno == EAGAIN && busy++ < 10) {
                        /* adjust backoff */
                        if ((ts.tv_nsec *= 10) >= NANOSEC) {
                                ts.tv_sec++;
                                ts.tv_nsec = 100;
                        }
                        (void) nanosleep(&ts, NULL);
#ifdef  DEBUG
                        (void) printf("door_call failed EAGAIN # %d\n", busy);
#endif  /* DEBUG */
                        (void) mutex_lock(&_door_lock);
                        goto try_again;
                }
                perror("door call");
                return (NOSERVER);
        }

        *adata = (int)param.data_size;
        *ndata = (int)param.rsize;
        /*LINTED*/
        *dptr = (labeld_data_t *)param.data_ptr;

        if (*adata == 0 || *dptr == NULL) {
#ifdef  DEBUG
                (void) printf("\tNo data returned, size = %lu, dptr = %p\n",
                    (unsigned long)*adata, (void *)*dptr);
#endif  /* DEBUG */
                return (NOSERVER);
        }
#ifdef  DEBUG
        (void) printf("call buf = %x, buf size  = %d, call size = %d\n",
            callptr, buf_size, return_size);
        (void) printf("retn buf = %x, buf size  = %d, retn size = %d\n",
            *dptr, *ndata, *adata);
        (void) printf("\treply status = %d\n", (*dptr)->param.aret.ret);
#endif  /* DEBUG */
        return ((*dptr)->param.aret.ret);

}  /* __call_labeld */