source: mainline/uspace/lib/label/src/mbr.c@ 603c1d1f

/*
 * Copyright (c) 2015 Jiri Svoboda
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup liblabel
 * @{
 */
/**
 * @file Master Boot Record label
 */

#include <block.h>
#include <byteorder.h>
#include <errno.h>
#include <mem.h>
#include <stdlib.h>

#include "std/mbr.h"
#include "mbr.h"

static int mbr_open(service_id_t, label_t **);
static int mbr_create(service_id_t, label_t **);
static void mbr_close(label_t *);
static int mbr_destroy(label_t *);
static int mbr_get_info(label_t *, label_info_t *);
static label_part_t *mbr_part_first(label_t *);
static label_part_t *mbr_part_next(label_part_t *);
static void mbr_part_get_info(label_part_t *, label_part_info_t *);
static int mbr_part_create(label_t *, label_part_spec_t *, label_part_t **);
static int mbr_part_destroy(label_part_t *);

static void mbr_unused_pte(mbr_pte_t *);
static int mbr_part_to_pte(label_part_t *, mbr_pte_t *);
static int mbr_pte_to_part(label_t *, mbr_pte_t *, int);
static int mbr_pte_update(label_t *, mbr_pte_t *, int);

label_ops_t mbr_label_ops = {
        .open = mbr_open,
        .create = mbr_create,
        .close = mbr_close,
        .destroy = mbr_destroy,
        .get_info = mbr_get_info,
        .part_first = mbr_part_first,
        .part_next = mbr_part_next,
        .part_get_info = mbr_part_get_info,
        .part_create = mbr_part_create,
        .part_destroy = mbr_part_destroy
};

static int mbr_open(service_id_t sid, label_t **rlabel)
{
        label_t *label = NULL;
        mbr_br_block_t *mbr = NULL;
        mbr_pte_t *eptr;
        uint16_t sgn;
        size_t bsize;
        aoff64_t nblocks;
        uint32_t entry;
        int rc;

        rc = block_get_bsize(sid, &bsize);
        if (rc != EOK) {
                rc = EIO;
                goto error;
        }

        rc = block_get_nblocks(sid, &nblocks);
        if (rc != EOK) {
                rc = EIO;
                goto error;
        }

        if (bsize < 512 || (bsize % 512) != 0) {
                rc = EINVAL;
                goto error;
        }

        if (nblocks < mbr_ablock0) {
                rc = EINVAL;
                goto error;
        }

        mbr = calloc(1, bsize);
        if (mbr == NULL) {
                rc = ENOMEM;
                goto error;
        }

        rc = block_read_direct(sid, mbr_ba, 1, mbr);
        if (rc != EOK) {
                rc = EIO;
                goto error;
        }

        label = calloc(1, sizeof(label_t));
        if (label == NULL)
                return ENOMEM;

        list_initialize(&label->parts);

        /* Verify boot record signature */
        sgn = uint16_t_le2host(mbr->signature);
        if (sgn != mbr_br_signature) {
                rc = EIO;
                goto error;
        }

        for (entry = 0; entry < mbr_nprimary; entry++) {
                eptr = &mbr->pte[entry];
                rc = mbr_pte_to_part(label, eptr, entry + 1);
                if (rc != EOK)
                        goto error;
        }

        free(mbr);
        mbr = NULL;

        label->ops = &mbr_label_ops;
        label->ltype = lt_mbr;
        label->svc_id = sid;
        label->block_size = bsize;
        label->ablock0 = mbr_ablock0;
        label->anblocks = nblocks - mbr_ablock0;
        label->pri_entries = mbr_nprimary;
        *rlabel = label;
        return EOK;
error:
        free(mbr);
        free(label);
        return rc;
}

static int mbr_create(service_id_t sid, label_t **rlabel)
{
        label_t *label = NULL;
        mbr_br_block_t *mbr = NULL;
        aoff64_t nblocks;
        size_t bsize;
        int i;
        int rc;

        rc = block_get_bsize(sid, &bsize);
        if (rc != EOK) {
                rc = EIO;
                goto error;
        }

        rc = block_get_nblocks(sid, &nblocks);
        if (rc != EOK) {
                rc = EIO;
                goto error;
        }

        mbr = calloc(1, bsize);
        if (mbr == NULL) {
                rc = ENOMEM;
                goto error;
        }

        label = calloc(1, sizeof(label_t));
        if (label == NULL)
                return ENOMEM;

        list_initialize(&label->parts);

        mbr->media_id = 0;
        mbr->pad0 = 0;
        for (i = 0; i < mbr_nprimary; i++)
                mbr_unused_pte(&mbr->pte[i]);
        mbr->signature = host2uint16_t_le(mbr_br_signature);

        rc = block_write_direct(sid, mbr_ba, 1, mbr);
        if (rc != EOK) {
                rc = EIO;
                goto error;
        }

        free(mbr);
        mbr = NULL;

        label->ops = &mbr_label_ops;
        label->ltype = lt_mbr;
        label->block_size = bsize;
        label->svc_id = sid;
        label->ablock0 = mbr_ablock0;
        label->anblocks = nblocks - mbr_ablock0;
        label->pri_entries = mbr_nprimary;

        *rlabel = label;
        return EOK;
error:
        free(mbr);
        free(label);
        return rc;
}

static void mbr_close(label_t *label)
{
        label_part_t *part;

        part = mbr_part_first(label);
        while (part != NULL) {
                list_remove(&part->llabel);
                free(part);

                part = mbr_part_first(label);
        }

        free(label);
}

static int mbr_destroy(label_t *label)
{
        mbr_br_block_t *mbr = NULL;
        label_part_t *part;
        int rc;

        part = mbr_part_first(label);
        if (part != NULL) {
                rc = ENOTEMPTY;
                goto error;
        }

        mbr = calloc(1, label->block_size);
        if (mbr == NULL) {
                rc = ENOMEM;
                goto error;
        }

        rc = block_write_direct(label->svc_id, mbr_ba, 1, mbr);
        if (rc != EOK) {
                rc = EIO;
                goto error;
        }

        free(mbr);
        mbr = NULL;

        free(label);
        return EOK;
error:
        free(mbr);
        return rc;
}

static int mbr_get_info(label_t *label, label_info_t *linfo)
{
        memset(linfo, 0, sizeof(label_info_t));
        linfo->dcnt = dc_label;
        linfo->ltype = lt_mbr;
        linfo->ablock0 = label->ablock0;
        linfo->anblocks = label->anblocks;
        return EOK;
}

static label_part_t *mbr_part_first(label_t *label)
{
        link_t *link;

        link = list_first(&label->parts);
        if (link == NULL)
                return NULL;

        return list_get_instance(link, label_part_t, llabel);
}

static label_part_t *mbr_part_next(label_part_t *part)
{
        link_t *link;

        link = list_next(&part->llabel, &part->label->parts);
        if (link == NULL)
                return NULL;

        return list_get_instance(link, label_part_t, llabel);
}

static void mbr_part_get_info(label_part_t *part, label_part_info_t *pinfo)
{
        pinfo->index = part->index;
        pinfo->block0 = part->block0;
        pinfo->nblocks = part->nblocks;
}

static int mbr_part_create(label_t *label, label_part_spec_t *pspec,
    label_part_t **rpart)
{
        label_part_t *part;
        mbr_pte_t pte;
        int rc;

        part = calloc(1, sizeof(label_part_t));
        if (part == NULL)
                return ENOMEM;

        /* XXX Verify index, block0, nblocks */

        if (pspec->index < 1 || pspec->index > label->pri_entries) {
                rc = EINVAL;
                goto error;
        }

        /* XXX Check if index is used */

        part->label = label;
        part->index = pspec->index;
        part->block0 = pspec->block0;
        part->nblocks = pspec->nblocks;
        part->ptype = pspec->ptype;

        rc = mbr_part_to_pte(part, &pte);
        if (rc != EOK) {
                rc = EINVAL;
                goto error;
        }

        rc = mbr_pte_update(label, &pte, pspec->index - 1);
        if (rc != EOK) {
                rc = EIO;
                goto error;
        }

        list_append(&part->llabel, &label->parts);

        *rpart = part;
        return EOK;
error:
        free(part);
        return rc;
}

static int mbr_part_destroy(label_part_t *part)
{
        mbr_pte_t pte;
        int rc;

        /* Prepare unused partition table entry */
        mbr_unused_pte(&pte);

        /* Modify partition table */
        rc = mbr_pte_update(part->label, &pte, part->index - 1);
        if (rc != EOK)
                return EIO;

        list_remove(&part->llabel);
        free(part);
        return EOK;
}

static void mbr_unused_pte(mbr_pte_t *pte)
{
        memset(pte, 0, sizeof(mbr_pte_t));
}

static int mbr_part_to_pte(label_part_t *part, mbr_pte_t *pte)
{
        if ((part->block0 >> 32) != 0)
                return EINVAL;
        if ((part->nblocks >> 32) != 0)
                return EINVAL;
        if ((part->ptype >> 8) != 0)
                return EINVAL;

        memset(pte, 0, sizeof(mbr_pte_t));
        pte->ptype = part->ptype;
        pte->first_lba = host2uint32_t_le(part->block0);
        pte->length = host2uint32_t_le(part->nblocks);
        return EOK;
}

static int mbr_pte_to_part(label_t *label, mbr_pte_t *pte, int index)
{
        label_part_t *part;
        uint32_t block0;
        uint32_t nblocks;

        block0 = uint32_t_le2host(pte->first_lba);
        nblocks = uint32_t_le2host(pte->length);

        /* See UEFI specification 2.0 section 5.2.1 Legacy Master Boot Record */
        if (pte->ptype == mbr_pt_unused || pte->ptype == mbr_pt_extended ||
            nblocks == 0)
                return EOK;

        part = calloc(1, sizeof(label_part_t));
        if (part == NULL)
                return ENOMEM;

        part->index = index;
        part->block0 = block0;
        part->nblocks = nblocks;

        /*
         * TODO: Verify
         *   - partition must reside on disk
         *   - partition must not overlap any other partition
         */

        part->label = label;
        list_append(&part->llabel, &label->parts);
        return EOK;
}

/** Update partition table entry at specified index.
 *
 * Replace partition entry at index @a index with the contents of
 * @a pte.
 */
static int mbr_pte_update(label_t *label, mbr_pte_t *pte, int index)
{
        mbr_br_block_t *br;
        int rc;

        br = calloc(1, label->block_size);
        if (br == NULL)
                return ENOMEM;

        rc = block_read_direct(label->svc_id, mbr_ba, 1, br);
        if (rc != EOK) {
                rc = EIO;
                goto error;
        }

        br->pte[index] = *pte;

        rc = block_write_direct(label->svc_id, mbr_ba, 1, br);
        if (rc != EOK) {
                rc = EIO;
                goto error;
        }

        free(br);
        return EOK;
error:
        free(br);
        return rc;
}

/** @}
 */