/*
 * 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 2007 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * This file contains kernel property decode routines adopted from
 * sunddi.c and ddi_impl.c. The following changes have been applied.
 *
 * (1) Replace kmem_alloc by malloc. Remove negative indexing
 * (2) Decoding applies only to prom properties.
 * (3) For strings, the return value is a composite string, not a string array.
 * (4) impl_ddi_prop_int_from_prom() uses _LITTLE_ENDIAN from isa_defs.h
 *
 * XXX This file should be kept in sync with kernel property encoding.
 */

#include <stdlib.h>
#include <strings.h>
#include <synch.h>
#include <ctype.h>
#include <sys/types.h>
#include <sys/dditypes.h>
#include <sys/ddipropdefs.h>
#include <sys/isa_defs.h>

#include "libdevinfo.h"

/*
 * Return an integer in native machine format from an OBP 1275 integer
 * representation, which is big-endian, with no particular alignment
 * guarantees. intp points to the OBP data, and n the number of bytes.
 *
 * Byte-swapping may be needed on some implementations.
 */
int
impl_di_prop_int_from_prom(uchar_t *intp, int n)
{
        int i = 0;

#if defined(_LITTLE_ENDIAN)
        intp += n;
        while (n-- > 0) {
                i = (i << 8) | *(--intp);
        }
#else
        while (n-- > 0) {
                i = (i << 8) | *intp++;
        }
#endif  /* defined(_LITTLE_ENDIAN) */

        return (i);
}

/*
 * Reset the current location pointer in the property handle to the
 * beginning of the data.
 */
void
di_prop_reset_pos(prop_handle_t *ph)
{
        ph->ph_cur_pos = ph->ph_data;
        ph->ph_save_pos = ph->ph_data;
}

/*
 * Restore the current location pointer in the property handle to the
 * saved position.
 */
void
di_prop_save_pos(prop_handle_t *ph)
{
        ph->ph_save_pos = ph->ph_cur_pos;
}

/*
 * Save the location that the current location poiner is pointing to..
 */
void
di_prop_restore_pos(prop_handle_t *ph)
{
        ph->ph_cur_pos = ph->ph_save_pos;
}

/*
 * Property encode/decode functions
 */

/*
 * Decode an array of integers property
 */
static int
di_prop_fm_decode_ints(prop_handle_t *ph, void *data, uint_t *nelements)
{
        int     i;
        int     cnt = 0;
        int     *tmp;
        int     *intp;
        int     n;

        /*
         * Figure out how many array elements there are by going through the
         * data without decoding it first and counting.
         */
        for (;;) {
                i = DDI_PROP_INT(ph, DDI_PROP_CMD_SKIP, NULL);
                if (i < 0)
                        break;
                cnt++;
        }

        /*
         * If there are no elements return an error
         */
        if (cnt == 0)
                return (DDI_PROP_END_OF_DATA);

        /*
         * If we cannot skip through the data, we cannot decode it
         */
        if (i == DDI_PROP_RESULT_ERROR)
                return (DDI_PROP_CANNOT_DECODE);

        /*
         * Reset the data pointer to the beginning of the encoded data
         */
        di_prop_reset_pos(ph);

        /*
         * Allocated memory to store the decoded value in.
         */
        if ((intp = malloc(cnt * sizeof (int))) == NULL) {
                return (DDI_PROP_CANNOT_DECODE);
        }


        /*
         * Decode each elemente and place it in the space we just allocated
         */
        tmp = intp;
        for (n = 0; n < cnt; n++, tmp++) {
                i = DDI_PROP_INT(ph, DDI_PROP_CMD_DECODE, tmp);
                if (i < DDI_PROP_RESULT_OK) {
                        /*
                         * Free the space we just allocated
                         * and return an error.
                         */
                        free(intp);
                        switch (i) {
                        case DDI_PROP_RESULT_EOF:
                                return (DDI_PROP_END_OF_DATA);

                        case DDI_PROP_RESULT_ERROR:
                                return (DDI_PROP_CANNOT_DECODE);
                        }
                }
        }

        *nelements = cnt;
        *(int **)data = intp;

        return (DDI_PROP_SUCCESS);
}

/*
 * Decode an array of strings.
 */
static int
di_prop_fm_decode_strings(prop_handle_t *ph, void *data, uint_t *nelements)
{
        int             cnt = 0;
        char            *strs;
        char            *tmp;
        int             size;
        int             i;
        int             n;
        int             nbytes;

        /*
         * Figure out how much memory we need for the sum total
         */
        nbytes = 0;

        for (;;) {
                /*
                 * Get the decoded size of the current encoded string.
                 */
                size = DDI_PROP_STR(ph, DDI_PROP_CMD_GET_DSIZE, NULL);
                if (size < 0)
                        break;

                cnt++;
                nbytes += size;
        }

        /*
         * If there are no elements return an error
         */
        if (cnt == 0)
                return (DDI_PROP_END_OF_DATA);

        /*
         * If we cannot skip through the data, we cannot decode it
         */
        if (size == DDI_PROP_RESULT_ERROR)
                return (DDI_PROP_CANNOT_DECODE);

        /*
         * Allocate memory in which to store the decoded strings.
         */
        if ((strs = malloc(nbytes)) == NULL) {
                return (DDI_PROP_CANNOT_DECODE);
        }

        /*
         * Finally, we can decode each string
         */
        di_prop_reset_pos(ph);
        tmp = strs;
        for (n = 0; n < cnt; n++) {
                i = DDI_PROP_STR(ph, DDI_PROP_CMD_DECODE, tmp);
                if (i < DDI_PROP_RESULT_OK) {
                        /*
                         * Free the space we just allocated
                         * and return an error
                         */
                        free(strs);
                        switch (i) {
                        case DDI_PROP_RESULT_EOF:
                                return (DDI_PROP_END_OF_DATA);

                        case DDI_PROP_RESULT_ERROR:
                                return (DDI_PROP_CANNOT_DECODE);
                        }
                }
                tmp += strlen(tmp) + 1;
        }

        *(char **)data = strs;
        *nelements = cnt;

        return (DDI_PROP_SUCCESS);
}

/*
 * Decode an array of bytes.
 */
static int
di_prop_fm_decode_bytes(prop_handle_t *ph, void *data, uint_t *nelements)
{
        uchar_t         *tmp;
        int             nbytes;
        int             i;

        /*
         * If there are no elements return an error
         */
        if (ph->ph_size == 0)
                return (DDI_PROP_END_OF_DATA);

        /*
         * Get the size of the encoded array of bytes.
         */
        nbytes = DDI_PROP_BYTES(ph, DDI_PROP_CMD_GET_DSIZE,
                data, ph->ph_size);
        if (nbytes < DDI_PROP_RESULT_OK) {
                switch (nbytes) {
                case DDI_PROP_RESULT_EOF:
                        return (DDI_PROP_END_OF_DATA);

                case DDI_PROP_RESULT_ERROR:
                        return (DDI_PROP_CANNOT_DECODE);
                }
        }

        /*
         * Allocated memory to store the decoded value in.
         */
        if ((tmp = malloc(nbytes)) == NULL) {
                return (DDI_PROP_CANNOT_DECODE);
        }

        /*
         * Decode each element and place it in the space we just allocated
         */
        i = DDI_PROP_BYTES(ph, DDI_PROP_CMD_DECODE, tmp, nbytes);
        if (i < DDI_PROP_RESULT_OK) {
                /*
                 * Free the space we just allocated
                 * and return an error
                 */
                free(tmp);
                switch (i) {
                case DDI_PROP_RESULT_EOF:
                        return (DDI_PROP_END_OF_DATA);

                case DDI_PROP_RESULT_ERROR:
                        return (DDI_PROP_CANNOT_DECODE);
                }
        }

        *(uchar_t **)data = tmp;
        *nelements = nbytes;

        return (DDI_PROP_SUCCESS);
}

/*
 * OBP 1275 integer, string and byte operators.
 *
 * DDI_PROP_CMD_DECODE:
 *
 *      DDI_PROP_RESULT_ERROR:          cannot decode the data
 *      DDI_PROP_RESULT_EOF:            end of data
 *      DDI_PROP_OK:                    data was decoded
 *
 * DDI_PROP_CMD_ENCODE:
 *
 *      DDI_PROP_RESULT_ERROR:          cannot encode the data
 *      DDI_PROP_RESULT_EOF:            end of data
 *      DDI_PROP_OK:                    data was encoded
 *
 * DDI_PROP_CMD_SKIP:
 *
 *      DDI_PROP_RESULT_ERROR:          cannot skip the data
 *      DDI_PROP_RESULT_EOF:            end of data
 *      DDI_PROP_OK:                    data was skipped
 *
 * DDI_PROP_CMD_GET_ESIZE:
 *
 *      DDI_PROP_RESULT_ERROR:          cannot get encoded size
 *      DDI_PROP_RESULT_EOF:            end of data
 *      > 0:                            the encoded size
 *
 * DDI_PROP_CMD_GET_DSIZE:
 *
 *      DDI_PROP_RESULT_ERROR:          cannot get decoded size
 *      DDI_PROP_RESULT_EOF:            end of data
 *      > 0:                            the decoded size
 */

/*
 * OBP 1275 integer operator
 *
 * OBP properties are a byte stream of data, so integers may not be
 * properly aligned. Therefore we need to copy them one byte at a time.
 */
int
di_prop_1275_int(prop_handle_t *ph, uint_t cmd, int *data)
{
        int     i;

        switch (cmd) {
        case DDI_PROP_CMD_DECODE:
                /*
                 * Check that there is encoded data
                 */
                if (ph->ph_cur_pos == NULL || ph->ph_size == 0)
                        return (DDI_PROP_RESULT_ERROR);
                if (ph->ph_flags & PH_FROM_PROM) {
                        i = ph->ph_size < PROP_1275_INT_SIZE ?
                            ph->ph_size : PROP_1275_INT_SIZE;
                        if ((int *)ph->ph_cur_pos > ((int *)ph->ph_data +
                            ph->ph_size - i))
                                return (DDI_PROP_RESULT_ERROR);
                } else if (ph->ph_size < sizeof (int) ||
                    ((int *)ph->ph_cur_pos > ((int *)ph->ph_data +
                    ph->ph_size - sizeof (int)))) {
                        return (DDI_PROP_RESULT_ERROR);
                }

                /*
                 * Copy the integer, using the implementation-specific
                 * copy function if the property is coming from the PROM.
                 */
                if (ph->ph_flags & PH_FROM_PROM) {
                        *data = impl_di_prop_int_from_prom(
                            (uchar_t *)ph->ph_cur_pos,
                            (ph->ph_size < PROP_1275_INT_SIZE) ?
                            ph->ph_size : PROP_1275_INT_SIZE);
                } else {
                        bcopy(ph->ph_cur_pos, (caddr_t)data, sizeof (int));
                }

                /*
                 * Move the current location to the start of the next
                 * bit of undecoded data.
                 */
                ph->ph_cur_pos = (uchar_t *)ph->ph_cur_pos + PROP_1275_INT_SIZE;
                return (DDI_PROP_RESULT_OK);

        case DDI_PROP_CMD_ENCODE:
                /*
                 * Check that there is room to encoded the data
                 */
                if (ph->ph_cur_pos == NULL || ph->ph_size == 0 ||
                    ph->ph_size < PROP_1275_INT_SIZE ||
                    ((int *)ph->ph_cur_pos > ((int *)ph->ph_data +
                    ph->ph_size - sizeof (int))))
                        return (DDI_PROP_RESULT_ERROR);

                /*
                 * Encode the integer into the byte stream one byte at a
                 * time.
                 */
                bcopy((caddr_t)data, ph->ph_cur_pos, sizeof (int));

                /*
                 * Move the current location to the start of the next bit of
                 * space where we can store encoded data.
                 */
                ph->ph_cur_pos = (uchar_t *)ph->ph_cur_pos + PROP_1275_INT_SIZE;
                return (DDI_PROP_RESULT_OK);

        case DDI_PROP_CMD_SKIP:
                /*
                 * Check that there is encoded data
                 */
                if (ph->ph_cur_pos == NULL || ph->ph_size == 0 ||
                    ph->ph_size < PROP_1275_INT_SIZE)
                        return (DDI_PROP_RESULT_ERROR);


                if ((caddr_t)ph->ph_cur_pos ==
                    (caddr_t)ph->ph_data + ph->ph_size) {
                        return (DDI_PROP_RESULT_EOF);
                } else if ((caddr_t)ph->ph_cur_pos >
                    (caddr_t)ph->ph_data + ph->ph_size) {
                        return (DDI_PROP_RESULT_EOF);
                }

                /*
                 * Move the current location to the start of the next bit of
                 * undecoded data.
                 */
                ph->ph_cur_pos = (uchar_t *)ph->ph_cur_pos + PROP_1275_INT_SIZE;
                return (DDI_PROP_RESULT_OK);

        case DDI_PROP_CMD_GET_ESIZE:
                /*
                 * Return the size of an encoded integer on OBP
                 */
                return (PROP_1275_INT_SIZE);

        case DDI_PROP_CMD_GET_DSIZE:
                /*
                 * Return the size of a decoded integer on the system.
                 */
                return (sizeof (int));
        }

        /*NOTREACHED*/
        return (0);     /* keep gcc happy */
}

/*
 * 64 bit integer operator
 *
 * This is an extension, defined by Sun, to the 1275 integer
 * operator.  This routine handles the encoding/decoding of
 * 64 bit integer properties.
 */
int
di_prop_int64_op(prop_handle_t *ph, uint_t cmd, int64_t *data)
{
        switch (cmd) {
        case DDI_PROP_CMD_DECODE:
                /*
                 * Check that there is encoded data
                 */
                if (ph->ph_cur_pos == NULL || ph->ph_size == 0)
                        return (DDI_PROP_RESULT_ERROR);
                if (ph->ph_flags & PH_FROM_PROM) {
                        return (DDI_PROP_RESULT_ERROR);
                } else if (ph->ph_size < sizeof (int64_t) ||
                    ((int64_t *)ph->ph_cur_pos > ((int64_t *)ph->ph_data +
                    ph->ph_size - sizeof (int64_t)))) {
                        return (DDI_PROP_RESULT_ERROR);
                }

                /*
                 * Copy the integer, using the implementation-specific
                 * copy function if the property is coming from the PROM.
                 */
                bcopy(ph->ph_cur_pos, (caddr_t)data, sizeof (int64_t));

                /*
                 * Move the current location to the start of the next
                 * bit of undecoded data.
                 */
                ph->ph_cur_pos = (uchar_t *)ph->ph_cur_pos +
                    sizeof (int64_t);
                return (DDI_PROP_RESULT_OK);

        case DDI_PROP_CMD_ENCODE:
                /*
                 * Check that there is room to encoded the data
                 */
                if (ph->ph_cur_pos == NULL || ph->ph_size == 0 ||
                    ph->ph_size < sizeof (int64_t) ||
                    ((int64_t *)ph->ph_cur_pos > ((int64_t *)ph->ph_data +
                    ph->ph_size - sizeof (int64_t))))
                        return (DDI_PROP_RESULT_ERROR);

                /*
                 * Encode the integer into the byte stream one byte at a
                 * time.
                 */
                bcopy((caddr_t)data, ph->ph_cur_pos, sizeof (int64_t));

                /*
                 * Move the current location to the start of the next bit of
                 * space where we can store encoded data.
                 */
                ph->ph_cur_pos = (uchar_t *)ph->ph_cur_pos +
                    sizeof (int64_t);
                return (DDI_PROP_RESULT_OK);

        case DDI_PROP_CMD_SKIP:
                /*
                 * Check that there is encoded data
                 */
                if (ph->ph_cur_pos == NULL || ph->ph_size == 0 ||
                    ph->ph_size < sizeof (int64_t))
                        return (DDI_PROP_RESULT_ERROR);


                if ((caddr_t)ph->ph_cur_pos ==
                    (caddr_t)ph->ph_data + ph->ph_size) {
                        return (DDI_PROP_RESULT_EOF);
                } else if ((caddr_t)ph->ph_cur_pos >
                    (caddr_t)ph->ph_data + ph->ph_size) {
                        return (DDI_PROP_RESULT_EOF);
                }

                /*
                 * Move the current location to the start of the next bit of
                 * undecoded data.
                 */
                ph->ph_cur_pos = (uchar_t *)ph->ph_cur_pos +
                    sizeof (int64_t);
                return (DDI_PROP_RESULT_OK);

        case DDI_PROP_CMD_GET_ESIZE:
                /*
                 * Return the size of an encoded integer on OBP
                 */
                return (sizeof (int64_t));

        case DDI_PROP_CMD_GET_DSIZE:
                /*
                 * Return the size of a decoded integer on the system.
                 */
                return (sizeof (int64_t));
        }

        /*NOTREACHED*/
        return (0);     /* keep gcc happy */
}

/*
 * OBP 1275 string operator.
 *
 * OBP strings are NULL terminated.
 */
int
di_prop_1275_string(prop_handle_t *ph, uint_t cmd, char *data)
{
        int     n;
        char    *p;
        char    *end;

        switch (cmd) {
        case DDI_PROP_CMD_DECODE:
                /*
                 * Check that there is encoded data
                 */
                if (ph->ph_cur_pos == NULL || ph->ph_size == 0) {
                        return (DDI_PROP_RESULT_ERROR);
                }

                n = strlen((char *)ph->ph_cur_pos) + 1;
                if ((char *)ph->ph_cur_pos > ((char *)ph->ph_data +
                    ph->ph_size - n)) {
                        return (DDI_PROP_RESULT_ERROR);
                }

                /*
                 * Copy the NULL terminated string
                 */
                bcopy((char *)ph->ph_cur_pos, data, n);

                /*
                 * Move the current location to the start of the next bit of
                 * undecoded data.
                 */
                ph->ph_cur_pos = (char *)ph->ph_cur_pos + n;
                return (DDI_PROP_RESULT_OK);

        case DDI_PROP_CMD_ENCODE:
                /*
                 * Check that there is room to encoded the data
                 */
                if (ph->ph_cur_pos == NULL || ph->ph_size == 0) {
                        return (DDI_PROP_RESULT_ERROR);
                }

                n = strlen(data) + 1;
                if ((char *)ph->ph_cur_pos > ((char *)ph->ph_data +
                    ph->ph_size - n)) {
                        return (DDI_PROP_RESULT_ERROR);
                }

                /*
                 * Copy the NULL terminated string
                 */
                bcopy(data, (char *)ph->ph_cur_pos, n);

                /*
                 * Move the current location to the start of the next bit of
                 * space where we can store encoded data.
                 */
                ph->ph_cur_pos = (char *)ph->ph_cur_pos + n;
                return (DDI_PROP_RESULT_OK);

        case DDI_PROP_CMD_SKIP:
                /*
                 * Check that there is encoded data
                 */
                if (ph->ph_cur_pos == NULL || ph->ph_size == 0) {
                        return (DDI_PROP_RESULT_ERROR);
                }

                /*
                 * Return the string length plus one for the NULL
                 * We know the size of the property, we need to
                 * ensure that the string is properly formatted,
                 * since we may be looking up random OBP data.
                 */
                p = (char *)ph->ph_cur_pos;
                end = (char *)ph->ph_data + ph->ph_size;

                if (p == end) {
                        return (DDI_PROP_RESULT_EOF);
                }

                /*
                 * Make sure each char is printable
                 */
                for (n = 0; p < end && isascii(*p) && !iscntrl(*p); n++, p++)
                        ;

                /* Check termination and non-zero length */
                if ((*p == 0) && (n != 0)) {
                        ph->ph_cur_pos = p + 1;
                        return (DDI_PROP_RESULT_OK);
                }

                return (DDI_PROP_RESULT_ERROR);

        case DDI_PROP_CMD_GET_ESIZE:
                /*
                 * Return the size of the encoded string on OBP.
                 */
                return (strlen(data) + 1);

        case DDI_PROP_CMD_GET_DSIZE:
                /*
                 * Return the string length plus one for the NULL
                 * We know the size of the property, we need to
                 * ensure that the string is properly formatted,
                 * since we may be looking up random OBP data.
                 */
                p = (char *)ph->ph_cur_pos;
                end = (char *)ph->ph_data + ph->ph_size;
                for (n = 0; p < end; n++) {
                        if (*p++ == '\0') {
                                ph->ph_cur_pos = p;
                                return (n+1);
                        }
                }

                /*
                 * Add check here to separate EOF and ERROR.
                 */
                if (p == end)
                        return (DDI_PROP_RESULT_EOF);

                return (DDI_PROP_RESULT_ERROR);

        }

        /*NOTREACHED*/
        return (0);     /* keep gcc happy */
}

/*
 * OBP 1275 byte operator
 *
 * Caller must specify the number of bytes to get. OBP encodes bytes
 * as a byte so there is a 1-to-1 translation.
 */
int
di_prop_1275_bytes(prop_handle_t *ph, uint_t cmd, uchar_t *data,
    uint_t nelements)
{
        switch (cmd) {
        case DDI_PROP_CMD_DECODE:
                /*
                 * Check that there is encoded data
                 */
                if (ph->ph_cur_pos == NULL || ph->ph_size == 0 ||
                    ph->ph_size < nelements ||
                    ((char *)ph->ph_cur_pos > ((char *)ph->ph_data +
                    ph->ph_size - nelements)))
                        return (DDI_PROP_RESULT_ERROR);

                /*
                 * Copy out the bytes
                 */
                bcopy((char *)ph->ph_cur_pos, (char *)data, nelements);

                /*
                 * Move the current location
                 */
                ph->ph_cur_pos = (char *)ph->ph_cur_pos + nelements;
                return (DDI_PROP_RESULT_OK);

        case DDI_PROP_CMD_ENCODE:
                /*
                 * Check that there is room to encode the data
                 */
                if (ph->ph_cur_pos == NULL || ph->ph_size == 0 ||
                    ph->ph_size < nelements ||
                    ((char *)ph->ph_cur_pos > ((char *)ph->ph_data +
                    ph->ph_size - nelements)))
                        return (DDI_PROP_RESULT_ERROR);

                /*
                 * Copy in the bytes
                 */
                bcopy((char *)data, (char *)ph->ph_cur_pos, nelements);

                /*
                 * Move the current location to the start of the next bit of
                 * space where we can store encoded data.
                 */
                ph->ph_cur_pos = (char *)ph->ph_cur_pos + nelements;
                return (DDI_PROP_RESULT_OK);

        case DDI_PROP_CMD_SKIP:
                /*
                 * Check that there is encoded data
                 */
                if (ph->ph_cur_pos == NULL || ph->ph_size == 0 ||
                    ph->ph_size < nelements)
                        return (DDI_PROP_RESULT_ERROR);

                if ((char *)ph->ph_cur_pos > ((char *)ph->ph_data +
                    ph->ph_size - nelements))
                        return (DDI_PROP_RESULT_EOF);

                /*
                 * Move the current location
                 */
                ph->ph_cur_pos = (char *)ph->ph_cur_pos + nelements;
                return (DDI_PROP_RESULT_OK);

        case DDI_PROP_CMD_GET_ESIZE:
                /*
                 * The size in bytes of the encoded size is the
                 * same as the decoded size provided by the caller.
                 */
                return (nelements);

        case DDI_PROP_CMD_GET_DSIZE:
                /*
                 * Just return the number of bytes specified by the caller.
                 */
                return (nelements);

        }

        /*NOTREACHED*/
        return (0);     /* keep gcc happy */
}

/*
 * Used for properties that come from the OBP, hardware configuration files,
 * or that are created by calls to ddi_prop_update(9F).
 */
static struct prop_handle_ops prop_1275_ops = {
        di_prop_1275_int,
        di_prop_1275_string,
        di_prop_1275_bytes,
        di_prop_int64_op
};

/*
 * Now the real thing:
 * Extract type-specific values of an property
 */
int
di_prop_decode_common(void *data, int size, int prop_type, int prom)
{
        int n;
        int nelements;
        char *cp, *end;
        prop_handle_t ph;
        int (*prop_decoder)(prop_handle_t *, void *, uint_t *);

        /*
         * If the encoded data came from software, no decoding needed
         */
        if (!prom) {
                switch (prop_type) {
                case DI_PROP_TYPE_INT:
                        if (size % sizeof (int))
                                nelements = -1;
                        else
                                nelements = size / sizeof (int);
                        break;

                case DI_PROP_TYPE_INT64:
                        if (size % sizeof (int64_t))
                                nelements = -1;
                        else
                                nelements = size / sizeof (int64_t);
                        break;

                case DI_PROP_TYPE_STRING:
                        nelements = 0;
                        cp = *(char **)data;
                        end = cp + size;
                        /*
                         * Don't trust the data passed in by the caller.
                         * Check every char to make sure it is indeed a
                         * string property.
                         */
                        while (cp < end) {
                                /* skip to next non-printable char */
                                for (n = 0; cp < end &&
                                    isascii(*cp) && !iscntrl(*cp); n++, cp++)
                                        ;

                                /*
                                 * Fail if reached end (i.e. last char != 0),
                                 * or has a non-printable char. A zero length
                                 * string is acceptable.
                                 */
                                if (cp == end || *cp != 0) {
                                        nelements = -1;
                                        break;
                                }
                                /*
                                 * Increment # strings and keep going
                                 */
                                nelements++;
                                cp++;
                        }

                        break;

                case DI_PROP_TYPE_BYTE:
                        nelements = size;
                }

                return (nelements);
        }

        /*
         * Get the encoded data
         */
        bzero((caddr_t)&ph, sizeof (prop_handle_t));
        ph.ph_data = *(uchar_t **)data;
        ph.ph_size = size;

        /*
         * The data came from prom, use the 1275 OBP decode/encode routines.
         */
        ph.ph_cur_pos = ph.ph_data;
        ph.ph_save_pos = ph.ph_data;
        ph.ph_ops = &prop_1275_ops;
        ph.ph_flags = PH_FROM_PROM;

        switch (prop_type) {
        case DI_PROP_TYPE_INT:
                prop_decoder = di_prop_fm_decode_ints;
                break;
        case DI_PROP_TYPE_STRING:
                prop_decoder = di_prop_fm_decode_strings;
                break;
        case DI_PROP_TYPE_BYTE:
        default:
                prop_decoder = di_prop_fm_decode_bytes;
                break;
        }

        if ((*prop_decoder)(&ph, data, (uint_t *)&nelements)
            != DDI_PROP_SUCCESS)
                return (-1);

        /*
         * Free the encoded data
         */
        if (size != 0)
                free(ph.ph_data);

        return (nelements);
}

void
di_slot_names_free(int count, di_slot_name_t *slot_names)
{
        if (slot_names == NULL)
                return;

        while (--count >= 0) {
                if (slot_names[count].name != NULL)
                        free(slot_names[count].name);
        }
        free(slot_names);
}

/*
 * 1275 "slot-names" format: [int][string1][string2]...[stringN]
 *      - [int] is a 1275 encoded integer
 *      - [string1]...[stringN] are concatenated null-terminated strings
 *      - each bit position in [int] represents a pci device number
 *      - each bit which is set in [int] represents a slot with a device
 *        number of that bit position
 *      - each string in [string1]...[stringN] identifies a slot name only
 *        for the bits which are set in [int]
 *      - the ordering of strings follow the ordering of bits set in [int]
 *
 * an allocated array of di_slot_name_t is returned through prop_data if
 * [int] is non-zero and the number of entries as the return value;
 * use di_slot_names_free() to free the array
 */
int
di_slot_names_decode(uchar_t *rawdata, int rawlen,
    di_slot_name_t **prop_data)
{
        char *sp, *maxsp;
        int count, i;
        size_t len;
        int slots;
        int maxcount = 0;
        int maxslots = 0;
        di_slot_name_t *slot_names = NULL;

        if (rawlen < sizeof (slots))
                goto ERROUT;

        slots = impl_di_prop_int_from_prom(rawdata, sizeof (slots));
        if (slots == 0) {
                *prop_data = NULL;
                return (0);
        }

        maxslots = sizeof (slots) * 8;
        count = 0;
        for (i = 0; i < maxslots; i++) {
                if (slots & (1 << i))
                        count++;
        }
        maxslots = i;
        maxcount = count;
        slot_names = malloc(sizeof (*slot_names) * maxcount);
        bzero(slot_names, sizeof (*slot_names) * maxcount);

        /* also handle unterminated strings */
        sp = (char *)(rawdata + sizeof (slots));
        maxsp = sp + (rawlen - sizeof (slots));
        count = 0;
        for (i = 0; i < maxslots; i++) {
                if (slots & (1 << i)) {
                        if (sp > maxsp)
                                break;
                        len = strnlen(sp, (maxsp - sp) + 1);
                        if (len == 0)
                                break;

                        slot_names[count].name =
                            malloc(sizeof (char) * (len + 1));
                        (void) strlcpy(slot_names[count].name, sp, len + 1);

                        slot_names[count].num = i;

                        sp += len + 1;
                        count++;
                }
        }

        /*
         * check if the number of strings match with the number of slots;
         * we can also get a lesser string count even when there appears to be
         * the correct number of strings if one or more pair of strings are
         * seperated by more than one NULL byte
         */
        if (count != maxcount)
                goto ERROUT;

        *prop_data = slot_names;
        return (maxcount);
        /*NOTREACHED*/
ERROUT:
        di_slot_names_free(maxcount, slot_names);
        *prop_data = NULL;
        return (-1);
}