source: mainline/uspace/lib/bithenge/src/helenos/block.c

/*
 * Copyright (c) 2024 Jiri Svoboda
 * Copyright (c) 2012 Sean Bartell
 * 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 bithenge
 * @{
 */
/**
 * @file
 * Access block devices as blobs.
 * @todo Provide more information about the block device (block size).
 */

#include <assert.h>
#include <block.h>
#include <errno.h>
#include <loc.h>
#include <macros.h>
#include <stdlib.h>
#include <bithenge/blob.h>
#include "block.h"

typedef struct {
        bithenge_blob_t base;
        service_id_t service_id;
        aoff64_t size;
} block_blob_t;

static inline block_blob_t *blob_as_block(bithenge_blob_t *base)
{
        return (block_blob_t *)base;
}

static inline bithenge_blob_t *block_as_blob(block_blob_t *blob)
{
        return &blob->base;
}

static errno_t block_size(bithenge_blob_t *base, aoff64_t *size)
{
        block_blob_t *self = blob_as_block(base);
        *size = self->size;
        return EOK;
}

static errno_t block_read(bithenge_blob_t *base, aoff64_t offset, char *buffer,
    aoff64_t *size)
{
        block_blob_t *self = blob_as_block(base);
        if (offset > self->size)
                return ELIMIT;
        *size = min(*size, self->size - offset);
        return block_read_bytes_direct(self->service_id, offset, *size, buffer);
}

static void block_destroy(bithenge_blob_t *base)
{
        block_blob_t *self = blob_as_block(base);
        block_fini(self->service_id);
        free(self);
}

static const bithenge_random_access_blob_ops_t block_ops = {
        .size = block_size,
        .read = block_read,
        .destroy = block_destroy,
};

/** Create a blob for a block device. The blob must be freed with
 * @a bithenge_node_t::bithenge_node_destroy after it is used.
 * @param[out] out Stores the created blob.
 * @param service_id The service ID of the block device.
 * @return EOK on success or an error code from errno.h.
 */
errno_t bithenge_new_block_blob(bithenge_node_t **out, service_id_t service_id)
{
        assert(out);

        // Initialize libblock
        errno_t rc;
        rc = block_init(service_id);
        if (rc != EOK)
                return rc;

        // Calculate total device size
        size_t bsize;
        aoff64_t nblocks;
        aoff64_t size;
        rc = block_get_bsize(service_id, &bsize);
        if (rc != EOK) {
                block_fini(service_id);
                return rc;
        }
        rc = block_get_nblocks(service_id, &nblocks);
        if (rc != EOK) {
                block_fini(service_id);
                return rc;
        }
        size = bsize * nblocks;

        // Create blob
        block_blob_t *blob = malloc(sizeof(*blob));
        if (!blob) {
                block_fini(service_id);
                return ENOMEM;
        }
        rc = bithenge_init_random_access_blob(block_as_blob(blob),
            &block_ops);
        if (rc != EOK) {
                free(blob);
                block_fini(service_id);
                return rc;
        }
        blob->service_id = service_id;
        blob->size = size;
        *out = bithenge_blob_as_node(block_as_blob(blob));

        return EOK;
}

/** @}
 */