Archipelago » blktap-utils

/* 

 * Copyright (c) 2007, XenSource Inc.

 * 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.

 *     * Neither the name of XenSource Inc. nor the names of its contributors

 *       may be used to endorse or promote products derived from this software

 *       without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

 * "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 COPYRIGHT OWNER

 * OR CONTRIBUTORS 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.

 */

#ifdef HAVE_CONFIG_H

#include "config.h"

#endif

#include <errno.h>

#include <fcntl.h>

#include <stdio.h>

#include <stdlib.h>

#include <unistd.h>

#include <sys/statvfs.h>

#include <sys/stat.h>

#include <sys/ioctl.h>

#include <linux/fs.h>

#include <string.h>

#include "tapdisk.h"

#include "tapdisk-driver.h"

#include "tapdisk-interface.h"

void *img;

long int   disksector_size;

long int   disksize;

long int   diskinfo;

static int connections = 0;

struct tdram_state {

        int fd;

};

/*Get Image size, secsize*/

static int get_image_info(int fd, td_disk_info_t *info)

{

        int ret;

        struct stat stat;

        ret = fstat(fd, &stat);

        if (ret != 0) {

                DPRINTF("ERROR: fstat failed, Couldn't stat image");

                return -EINVAL;

        }

        if (S_ISBLK(stat.st_mode)) {

                /*Accessing block device directly*/

                info->size = 0;

                if (ioctl(fd,BLKGETSIZE,&info->size)!=0) {

                        DPRINTF("ERR: BLKGETSIZE failed, couldn't stat image");

                        return -EINVAL;

                }

                DPRINTF("Image size: \n\tpre sector_shift  [%llu]\n\tpost "

                        "sector_shift [%llu]\n",

                        (long long unsigned)(info->size << SECTOR_SHIFT),

                        (long long unsigned)info->size);

                /*Get the sector size*/

#if defined(BLKSSZGET)

                {

                        info->sector_size = DEFAULT_SECTOR_SIZE;

                        ioctl(fd, BLKSSZGET, &info->sector_size);

                        if (info->sector_size != DEFAULT_SECTOR_SIZE)

                                DPRINTF("Note: sector size is %ld (not %d)\n",

                                        info->sector_size, DEFAULT_SECTOR_SIZE);

                }

#else

                info->sector_size = DEFAULT_SECTOR_SIZE;

#endif

        } else {

                /*Local file? try fstat instead*/

                info->size = (stat.st_size >> SECTOR_SHIFT);

                info->sector_size = DEFAULT_SECTOR_SIZE;

                DPRINTF("Image size: \n\tpre sector_shift  [%llu]\n\tpost "

                        "sector_shift [%llu]\n",

                        (long long unsigned)(info->size << SECTOR_SHIFT),

                        (long long unsigned)info->size);

        }

        if (info->size == 0) {                

                info->size =((uint64_t) MAX_RAMDISK_SIZE);

                info->sector_size = DEFAULT_SECTOR_SIZE;

        }

        info->info = 0;

        /*Store variables locally*/

        disksector_size = info->sector_size;

        disksize        = info->size;

        diskinfo        = info->info;

        DPRINTF("Image sector_size: \n\t[%lu]\n",

                info->sector_size);

        return 0;

}

/* Open the disk file and initialize ram state. */

int tdram_open (td_driver_t *driver, const char *name, td_flag_t flags)

{

        char *p;

        uint64_t size;

        int i, fd, ret = 0, count = 0, o_flags;

        struct tdram_state *prv = (struct tdram_state *)driver->data;

        connections++;

        if (connections > 1) {

                driver->info.sector_size = disksector_size;

                driver->info.size        = disksize;

                driver->info.info        = diskinfo; 

                DPRINTF("Image already open, returning parameters:\n");

                DPRINTF("Image size: \n\tpre sector_shift  [%llu]\n\tpost "

                        "sector_shift [%llu]\n",

                        (long long unsigned)(driver->info.size << SECTOR_SHIFT),

                        (long long unsigned)driver->info.size);

                DPRINTF("Image sector_size: \n\t[%lu]\n",

                        driver->info.sector_size);

                prv->fd = -1;

                goto done;

        }

        /* Open the file */

        o_flags = O_DIRECT | O_LARGEFILE | 

                ((flags == TD_OPEN_RDONLY) ? O_RDONLY : O_RDWR);

        fd = open(name, o_flags);

        if ((fd == -1) && (errno == EINVAL)) {

                /* Maybe O_DIRECT isn't supported. */

                o_flags &= ~O_DIRECT;

                fd = open(name, o_flags);

                if (fd != -1) DPRINTF("WARNING: Accessing image without"

                                     "O_DIRECT! (%s)\n", name);

        } else if (fd != -1) DPRINTF("open(%s) with O_DIRECT\n", name);

        if (fd == -1) {

                DPRINTF("Unable to open [%s]!\n",name);

                ret = 0 - errno;

                goto done;

        }

        prv->fd = fd;

        ret = get_image_info(fd, &driver->info);

        size = MAX_RAMDISK_SIZE;

        if (driver->info.size > size) {

                DPRINTF("Disk exceeds limit, must be less than [%d]MB",

                        (MAX_RAMDISK_SIZE<<SECTOR_SHIFT)>>20);

                return -ENOMEM;

        }

        /*Read the image into memory*/

        if (posix_memalign(&img, DEFAULT_SECTOR_SIZE,

                           driver->info.size << SECTOR_SHIFT)) {

                DPRINTF("Mem malloc failed\n");

                return -errno;

        }

        p = img;

        DPRINTF("Reading %llu bytes.......",

                (long long unsigned)driver->info.size << SECTOR_SHIFT);

        for (i = 0; i < driver->info.size; i++) {

                ret = read(prv->fd, p, driver->info.sector_size);

                if (ret != driver->info.sector_size) {

                        DPRINTF("ret = %d, errno = %d\n", ret, errno);

                        ret = 0 - errno;

                        break;

                } else {

                        count += ret;

                        p = img + count;

                }

        }

        DPRINTF("[%d]\n",count);

        if (count != driver->info.size << SECTOR_SHIFT) {

                ret = -1;

        } else {

                ret = 0;

        }

done:

        return ret;

}

void tdram_queue_read(td_driver_t *driver, td_request_t treq)

{

        int      size    = treq.secs * driver->info.sector_size;

        uint64_t offset  = treq.sec * (uint64_t)driver->info.sector_size;

        memcpy(treq.buf, img + offset, size);

        td_complete_request(treq, 0);

}

void tdram_queue_write(td_driver_t *driver, td_request_t treq)

{

        int      size    = treq.secs * driver->info.sector_size;

        uint64_t offset  = treq.sec * (uint64_t)driver->info.sector_size;

        /* We assume that write access is controlled

         * at a higher level for multiple disks */

        memcpy(img + offset, treq.buf, size);

        td_complete_request(treq, 0);

}

int tdram_close(td_driver_t *driver)

{

        connections--;

        return 0;

}

int tdram_get_parent_id(td_driver_t *driver, td_disk_id_t *id)

{

        return TD_NO_PARENT;

}

int tdram_validate_parent(td_driver_t *driver,

                          td_driver_t *pdriver, td_flag_t flags)

{

        return -EINVAL;

}

struct tap_disk tapdisk_ram = {

        .disk_type          = "tapdisk_ram",

        .flags              = 0,

        .private_data_size  = sizeof(struct tdram_state),

        .td_open            = tdram_open,

        .td_close           = tdram_close,

        .td_queue_read      = tdram_queue_read,

        .td_queue_write     = tdram_queue_write,

        .td_get_parent_id   = tdram_get_parent_id,

        .td_validate_parent = tdram_validate_parent,

        .td_debug           = NULL,

};