Archipelago » qemu

/*

 * QEMU disk image utility

 *

 * Copyright (c) 2003-2008 Fabrice Bellard

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to deal

 * in the Software without restriction, including without limitation the rights

 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

 * copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL

 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

 * THE SOFTWARE.

 */

#include "qemu-common.h"

#include "qemu-option.h"

#include "osdep.h"

#include "block_int.h"

#include <stdio.h>

#ifdef _WIN32

#include <windows.h>

#endif

typedef struct img_cmd_t {

    const char *name;

    int (*handler)(int argc, char **argv);

} img_cmd_t;

/* Default to cache=writeback as data integrity is not important for qemu-tcg. */

#define BDRV_O_FLAGS BDRV_O_CACHE_WB

static void QEMU_NORETURN error(const char *fmt, ...)

{

    va_list ap;

    va_start(ap, fmt);

    fprintf(stderr, "qemu-img: ");

    vfprintf(stderr, fmt, ap);

    fprintf(stderr, "\n");

    exit(1);

    va_end(ap);

}

static void format_print(void *opaque, const char *name)

{

    printf(" %s", name);

}

/* Please keep in synch with qemu-img.texi */

static void help(void)

{

    const char *help_msg =

           "qemu-img version " QEMU_VERSION ", Copyright (c) 2004-2008 Fabrice Bellard\n"

           "usage: qemu-img command [command options]\n"

           "QEMU disk image utility\n"

           "\n"

           "Command syntax:\n"

#define DEF(option, callback, arg_string)        \

           "  " arg_string "\n"

#include "qemu-img-cmds.h"

#undef DEF

#undef GEN_DOCS

           "\n"

           "Command parameters:\n"

           "  'filename' is a disk image filename\n"

           "  'fmt' is the disk image format. It is guessed automatically in most cases\n"

           "  'size' is the disk image size in bytes. Optional suffixes\n"

           "    'k' or 'K' (kilobyte, 1024), 'M' (megabyte, 1024k), 'G' (gigabyte, 1024M)\n"

           "    and T (terabyte, 1024G) are supported. 'b' is ignored.\n"

           "  'output_filename' is the destination disk image filename\n"

           "  'output_fmt' is the destination format\n"

           "  'options' is a comma separated list of format specific options in a\n"

           "    name=value format. Use -o ? for an overview of the options supported by the\n"

           "    used format\n"

           "  '-c' indicates that target image must be compressed (qcow format only)\n"

           "  '-u' enables unsafe rebasing. It is assumed that old and new backing file\n"

           "       match exactly. The image doesn't need a working backing file before\n"

           "       rebasing in this case (useful for renaming the backing file)\n"

           "  '-h' with or without a command shows this help and lists the supported formats\n"

           "\n"

           "Parameters to snapshot subcommand:\n"

           "  'snapshot' is the name of the snapshot to create, apply or delete\n"

           "  '-a' applies a snapshot (revert disk to saved state)\n"

           "  '-c' creates a snapshot\n"

           "  '-d' deletes a snapshot\n"

           "  '-l' lists all snapshots in the given image\n";

    printf("%s\nSupported formats:", help_msg);

    bdrv_iterate_format(format_print, NULL);

    printf("\n");

    exit(1);

}

#if defined(WIN32)

/* XXX: put correct support for win32 */

static int read_password(char *buf, int buf_size)

{

    int c, i;

    printf("Password: ");

    fflush(stdout);

    i = 0;

    for(;;) {

        c = getchar();

        if (c == '\n')

            break;

        if (i < (buf_size - 1))

            buf[i++] = c;

    }

    buf[i] = '\0';

    return 0;

}

#else

#include <termios.h>

static struct termios oldtty;

static void term_exit(void)

{

    tcsetattr (0, TCSANOW, &oldtty);

}

static void term_init(void)

{

    struct termios tty;

    tcgetattr (0, &tty);

    oldtty = tty;

    tty.c_iflag &= ~(IGNBRK|BRKINT|PARMRK|ISTRIP

                          |INLCR|IGNCR|ICRNL|IXON);

    tty.c_oflag |= OPOST;

    tty.c_lflag &= ~(ECHO|ECHONL|ICANON|IEXTEN);

    tty.c_cflag &= ~(CSIZE|PARENB);

    tty.c_cflag |= CS8;

    tty.c_cc[VMIN] = 1;

    tty.c_cc[VTIME] = 0;

    tcsetattr (0, TCSANOW, &tty);

    atexit(term_exit);

}

static int read_password(char *buf, int buf_size)

{

    uint8_t ch;

    int i, ret;

    printf("password: ");

    fflush(stdout);

    term_init();

    i = 0;

    for(;;) {

        ret = read(0, &ch, 1);

        if (ret == -1) {

            if (errno == EAGAIN || errno == EINTR) {

                continue;

            } else {

                ret = -1;

                break;

            }

        } else if (ret == 0) {

            ret = -1;

            break;

        } else {

            if (ch == '\r') {

                ret = 0;

                break;

            }

            if (i < (buf_size - 1))

                buf[i++] = ch;

        }

    }

    term_exit();

    buf[i] = '\0';

    printf("\n");

    return ret;

}

#endif

static BlockDriverState *bdrv_new_open(const char *filename,

                                       const char *fmt,

                                       int flags)

{

    BlockDriverState *bs;

    BlockDriver *drv;

    char password[256];

    bs = bdrv_new("");

    if (!bs)

        error("Not enough memory");

    if (fmt) {

        drv = bdrv_find_format(fmt);

        if (!drv)

            error("Unknown file format '%s'", fmt);

    } else {

        drv = NULL;

    }

    if (bdrv_open(bs, filename, flags, drv) < 0) {

        error("Could not open '%s'", filename);

    }

    if (bdrv_is_encrypted(bs)) {

        printf("Disk image '%s' is encrypted.\n", filename);

        if (read_password(password, sizeof(password)) < 0)

            error("No password given");

        if (bdrv_set_key(bs, password) < 0)

            error("invalid password");

    }

    return bs;

}

static void add_old_style_options(const char *fmt, QEMUOptionParameter *list,

    int flags, const char *base_filename, const char *base_fmt)

{

    if (flags & BLOCK_FLAG_ENCRYPT) {

        if (set_option_parameter(list, BLOCK_OPT_ENCRYPT, "on")) {

            error("Encryption not supported for file format '%s'", fmt);

        }

    }

    if (flags & BLOCK_FLAG_COMPAT6) {

        if (set_option_parameter(list, BLOCK_OPT_COMPAT6, "on")) {

            error("VMDK version 6 not supported for file format '%s'", fmt);

        }

    }

    if (base_filename) {

        if (set_option_parameter(list, BLOCK_OPT_BACKING_FILE, base_filename)) {

            error("Backing file not supported for file format '%s'", fmt);

        }

    }

    if (base_fmt) {

        if (set_option_parameter(list, BLOCK_OPT_BACKING_FMT, base_fmt)) {

            error("Backing file format not supported for file format '%s'", fmt);

        }

    }

}

static int img_create(int argc, char **argv)

{

    int c, ret, flags;

    const char *fmt = "raw";

    const char *base_fmt = NULL;

    const char *filename;

    const char *base_filename = NULL;

    BlockDriver *drv;

    QEMUOptionParameter *param = NULL;

    char *options = NULL;

    flags = 0;

    for(;;) {

        c = getopt(argc, argv, "F:b:f:he6o:");

        if (c == -1)

            break;

        switch(c) {

        case 'h':

            help();

            break;

        case 'F':

            base_fmt = optarg;

            break;

        case 'b':

            base_filename = optarg;

            break;

        case 'f':

            fmt = optarg;

            break;

        case 'e':

            flags |= BLOCK_FLAG_ENCRYPT;

            break;

        case '6':

            flags |= BLOCK_FLAG_COMPAT6;

            break;

        case 'o':

            options = optarg;

            break;

        }

    }

    /* Find driver and parse its options */

    drv = bdrv_find_format(fmt);

    if (!drv)

        error("Unknown file format '%s'", fmt);

    if (options && !strcmp(options, "?")) {

        print_option_help(drv->create_options);

        return 0;

    }

    /* Create parameter list with default values */

    param = parse_option_parameters("", drv->create_options, param);

    set_option_parameter_int(param, BLOCK_OPT_SIZE, -1);

    /* Parse -o options */

    if (options) {

        param = parse_option_parameters(options, drv->create_options, param);

        if (param == NULL) {

            error("Invalid options for file format '%s'.", fmt);

        }

    }

    /* Get the filename */

    if (optind >= argc)

        help();

    filename = argv[optind++];

    /* Add size to parameters */

    if (optind < argc) {

        set_option_parameter(param, BLOCK_OPT_SIZE, argv[optind++]);

    }

    /* Add old-style options to parameters */

    add_old_style_options(fmt, param, flags, base_filename, base_fmt);

    // The size for the image must always be specified, with one exception:

    // If we are using a backing file, we can obtain the size from there

    if (get_option_parameter(param, BLOCK_OPT_SIZE)->value.n == -1) {

        QEMUOptionParameter *backing_file =

            get_option_parameter(param, BLOCK_OPT_BACKING_FILE);

        QEMUOptionParameter *backing_fmt =

            get_option_parameter(param, BLOCK_OPT_BACKING_FMT);

        if (backing_file && backing_file->value.s) {

            BlockDriverState *bs;

            uint64_t size;

            const char *fmt = NULL;

            char buf[32];

            if (backing_fmt && backing_fmt->value.s) {

                 if (bdrv_find_format(backing_fmt->value.s)) {

                     fmt = backing_fmt->value.s;

                } else {

                     error("Unknown backing file format '%s'",

                        backing_fmt->value.s);

                }

            }

            bs = bdrv_new_open(backing_file->value.s, fmt, BDRV_O_FLAGS);

            bdrv_get_geometry(bs, &size);

            size *= 512;

            bdrv_delete(bs);

            snprintf(buf, sizeof(buf), "%" PRId64, size);

            set_option_parameter(param, BLOCK_OPT_SIZE, buf);

        } else {

            error("Image creation needs a size parameter");

        }

    }

    printf("Formatting '%s', fmt=%s ", filename, fmt);

    print_option_parameters(param);

    puts("");

    ret = bdrv_create(drv, filename, param);

    free_option_parameters(param);

    if (ret < 0) {

        if (ret == -ENOTSUP) {

            error("Formatting or formatting option not supported for file format '%s'", fmt);

        } else if (ret == -EFBIG) {

            error("The image size is too large for file format '%s'", fmt);

        } else {

            error("%s: error while creating %s: %s", filename, fmt, strerror(-ret));

        }

    }

    return 0;

}

static int img_check(int argc, char **argv)

{

    int c, ret;

    const char *filename, *fmt;

    BlockDriverState *bs;

    fmt = NULL;

    for(;;) {

        c = getopt(argc, argv, "f:h");

        if (c == -1)

            break;

        switch(c) {

        case 'h':

            help();

            break;

        case 'f':

            fmt = optarg;

            break;

        }

    }

    if (optind >= argc)

        help();

    filename = argv[optind++];

    bs = bdrv_new_open(filename, fmt, BDRV_O_FLAGS);

    ret = bdrv_check(bs);

    switch(ret) {

    case 0:

        printf("No errors were found on the image.\n");

        break;

    case -ENOTSUP:

        error("This image format does not support checks");

        break;

    default:

        if (ret < 0) {

            error("An error occurred during the check");

        } else {

            printf("%d errors were found on the image.\n", ret);

        }

        break;

    }

    bdrv_delete(bs);

    return 0;

}

static int img_commit(int argc, char **argv)

{

    int c, ret;

    const char *filename, *fmt;

    BlockDriverState *bs;

    fmt = NULL;

    for(;;) {

        c = getopt(argc, argv, "f:h");

        if (c == -1)

            break;

        switch(c) {

        case 'h':

            help();

            break;

        case 'f':

            fmt = optarg;

            break;

        }

    }

    if (optind >= argc)

        help();

    filename = argv[optind++];

    bs = bdrv_new_open(filename, fmt, BDRV_O_FLAGS | BDRV_O_RDWR);

    ret = bdrv_commit(bs);

    switch(ret) {

    case 0:

        printf("Image committed.\n");

        break;

    case -ENOENT:

        error("No disk inserted");

        break;

    case -EACCES:

        error("Image is read-only");

        break;

    case -ENOTSUP:

        error("Image is already committed");

        break;

    default:

        error("Error while committing image");

        break;

    }

    bdrv_delete(bs);

    return 0;

}

static int is_not_zero(const uint8_t *sector, int len)

{

    int i;

    len >>= 2;

    for(i = 0;i < len; i++) {

        if (((uint32_t *)sector)[i] != 0)

            return 1;

    }

    return 0;

}

/*

 * Returns true iff the first sector pointed to by 'buf' contains at least

 * a non-NUL byte.

 *

 * 'pnum' is set to the number of sectors (including and immediately following

 * the first one) that are known to be in the same allocated/unallocated state.

 */

static int is_allocated_sectors(const uint8_t *buf, int n, int *pnum)

{

    int v, i;

    if (n <= 0) {

        *pnum = 0;

        return 0;

    }

    v = is_not_zero(buf, 512);

    for(i = 1; i < n; i++) {

        buf += 512;

        if (v != is_not_zero(buf, 512))

            break;

    }

    *pnum = i;

    return v;

}

/*

 * Compares two buffers sector by sector. Returns 0 if the first sector of both

 * buffers matches, non-zero otherwise.

 *

 * pnum is set to the number of sectors (including and immediately following

 * the first one) that are known to have the same comparison result

 */

static int compare_sectors(const uint8_t *buf1, const uint8_t *buf2, int n,

    int *pnum)

{

    int res, i;

    if (n <= 0) {

        *pnum = 0;

        return 0;

    }

    res = !!memcmp(buf1, buf2, 512);

    for(i = 1; i < n; i++) {

        buf1 += 512;

        buf2 += 512;

        if (!!memcmp(buf1, buf2, 512) != res) {

            break;

        }

    }

    *pnum = i;

    return res;

}

#define IO_BUF_SIZE (2 * 1024 * 1024)

static int img_convert(int argc, char **argv)

{

    int c, ret, n, n1, bs_n, bs_i, flags, cluster_size, cluster_sectors;

    const char *fmt, *out_fmt, *out_baseimg, *out_filename;

    BlockDriver *drv;

    BlockDriverState **bs, *out_bs;

    int64_t total_sectors, nb_sectors, sector_num, bs_offset;

    uint64_t bs_sectors;

    uint8_t * buf;

    const uint8_t *buf1;

    BlockDriverInfo bdi;

    QEMUOptionParameter *param = NULL;

    char *options = NULL;

    fmt = NULL;

    out_fmt = "raw";

    out_baseimg = NULL;

    flags = 0;

    for(;;) {

        c = getopt(argc, argv, "f:O:B:hce6o:");

        if (c == -1)

            break;

        switch(c) {

        case 'h':

            help();

            break;

        case 'f':

            fmt = optarg;

            break;

        case 'O':

            out_fmt = optarg;

            break;

        case 'B':

            out_baseimg = optarg;

            break;

        case 'c':

            flags |= BLOCK_FLAG_COMPRESS;

            break;

        case 'e':

            flags |= BLOCK_FLAG_ENCRYPT;

            break;

        case '6':

            flags |= BLOCK_FLAG_COMPAT6;

            break;

        case 'o':

            options = optarg;

            break;

        }

    }

    bs_n = argc - optind - 1;

    if (bs_n < 1) help();

    out_filename = argv[argc - 1];

    if (bs_n > 1 && out_baseimg)

        error("-B makes no sense when concatenating multiple input images");

    bs = calloc(bs_n, sizeof(BlockDriverState *));

    if (!bs)

        error("Out of memory");

    total_sectors = 0;

    for (bs_i = 0; bs_i < bs_n; bs_i++) {

        bs[bs_i] = bdrv_new_open(argv[optind + bs_i], fmt, BDRV_O_FLAGS);

        if (!bs[bs_i])

            error("Could not open '%s'", argv[optind + bs_i]);

        bdrv_get_geometry(bs[bs_i], &bs_sectors);

        total_sectors += bs_sectors;

    }

    /* Find driver and parse its options */

    drv = bdrv_find_format(out_fmt);

    if (!drv)

        error("Unknown file format '%s'", out_fmt);

    if (options && !strcmp(options, "?")) {

        print_option_help(drv->create_options);

        free(bs);

        return 0;

    }

    if (options) {

        param = parse_option_parameters(options, drv->create_options, param);

        if (param == NULL) {

            error("Invalid options for file format '%s'.", out_fmt);

        }

    } else {

        param = parse_option_parameters("", drv->create_options, param);

    }

    set_option_parameter_int(param, BLOCK_OPT_SIZE, total_sectors * 512);

    add_old_style_options(out_fmt, param, flags, out_baseimg, NULL);

    /* Check if compression is supported */

    if (flags & BLOCK_FLAG_COMPRESS) {

        QEMUOptionParameter *encryption =

            get_option_parameter(param, BLOCK_OPT_ENCRYPT);

        if (!drv->bdrv_write_compressed) {

            error("Compression not supported for this file format");

        }

        if (encryption && encryption->value.n) {

            error("Compression and encryption not supported at the same time");

        }

    }

    /* Create the new image */

    ret = bdrv_create(drv, out_filename, param);

    free_option_parameters(param);

    if (ret < 0) {

        if (ret == -ENOTSUP) {

            error("Formatting not supported for file format '%s'", out_fmt);

        } else if (ret == -EFBIG) {

            error("The image size is too large for file format '%s'", out_fmt);

        } else {

            error("%s: error while converting %s: %s", out_filename, out_fmt, strerror(-ret));

        }

    }

    out_bs = bdrv_new_open(out_filename, out_fmt, BDRV_O_FLAGS | BDRV_O_RDWR);

    bs_i = 0;

    bs_offset = 0;

    bdrv_get_geometry(bs[0], &bs_sectors);

    buf = qemu_malloc(IO_BUF_SIZE);

    if (flags & BLOCK_FLAG_COMPRESS) {

        if (bdrv_get_info(out_bs, &bdi) < 0)

            error("could not get block driver info");

        cluster_size = bdi.cluster_size;

        if (cluster_size <= 0 || cluster_size > IO_BUF_SIZE)

            error("invalid cluster size");

        cluster_sectors = cluster_size >> 9;

        sector_num = 0;

        for(;;) {

            int64_t bs_num;

            int remainder;

            uint8_t *buf2;

            nb_sectors = total_sectors - sector_num;

            if (nb_sectors <= 0)

                break;

            if (nb_sectors >= cluster_sectors)

                n = cluster_sectors;

            else

                n = nb_sectors;

            bs_num = sector_num - bs_offset;

            assert (bs_num >= 0);

            remainder = n;

            buf2 = buf;

            while (remainder > 0) {

                int nlow;

                while (bs_num == bs_sectors) {

                    bs_i++;

                    assert (bs_i < bs_n);

                    bs_offset += bs_sectors;

                    bdrv_get_geometry(bs[bs_i], &bs_sectors);

                    bs_num = 0;

                    /* printf("changing part: sector_num=%" PRId64 ", "

                       "bs_i=%d, bs_offset=%" PRId64 ", bs_sectors=%" PRId64

                       "\n", sector_num, bs_i, bs_offset, bs_sectors); */

                }

                assert (bs_num < bs_sectors);

                nlow = (remainder > bs_sectors - bs_num) ? bs_sectors - bs_num : remainder;

                if (bdrv_read(bs[bs_i], bs_num, buf2, nlow) < 0) 

                    error("error while reading");

                buf2 += nlow * 512;

                bs_num += nlow;

                remainder -= nlow;

            }

            assert (remainder == 0);

            if (n < cluster_sectors)

                memset(buf + n * 512, 0, cluster_size - n * 512);

            if (is_not_zero(buf, cluster_size)) {

                if (bdrv_write_compressed(out_bs, sector_num, buf,

                                          cluster_sectors) != 0)

                    error("error while compressing sector %" PRId64,

                          sector_num);

            }

            sector_num += n;

        }

        /* signal EOF to align */

        bdrv_write_compressed(out_bs, 0, NULL, 0);

    } else {

        int has_zero_init = bdrv_has_zero_init(out_bs);

        sector_num = 0; // total number of sectors converted so far

        for(;;) {

            nb_sectors = total_sectors - sector_num;

            if (nb_sectors <= 0)

                break;

            if (nb_sectors >= (IO_BUF_SIZE / 512))

                n = (IO_BUF_SIZE / 512);

            else

                n = nb_sectors;

            while (sector_num - bs_offset >= bs_sectors) {

                bs_i ++;

                assert (bs_i < bs_n);

                bs_offset += bs_sectors;

                bdrv_get_geometry(bs[bs_i], &bs_sectors);

                /* printf("changing part: sector_num=%" PRId64 ", bs_i=%d, "

                  "bs_offset=%" PRId64 ", bs_sectors=%" PRId64 "\n",

                   sector_num, bs_i, bs_offset, bs_sectors); */

            }

            if (n > bs_offset + bs_sectors - sector_num)

                n = bs_offset + bs_sectors - sector_num;

            if (has_zero_init) {

                /* If the output image is being created as a copy on write image,

                   assume that sectors which are unallocated in the input image

                   are present in both the output's and input's base images (no

                   need to copy them). */

                if (out_baseimg) {

                    if (!bdrv_is_allocated(bs[bs_i], sector_num - bs_offset,

                                           n, &n1)) {

                        sector_num += n1;

                        continue;

                    }

                    /* The next 'n1' sectors are allocated in the input image. Copy

                       only those as they may be followed by unallocated sectors. */

                    n = n1;

                }

            } else {

                n1 = n;

            }

            if (bdrv_read(bs[bs_i], sector_num - bs_offset, buf, n) < 0) 

                error("error while reading");

            /* NOTE: at the same time we convert, we do not write zero

               sectors to have a chance to compress the image. Ideally, we

               should add a specific call to have the info to go faster */

            buf1 = buf;

            while (n > 0) {

                /* If the output image is being created as a copy on write image,

                   copy all sectors even the ones containing only NUL bytes,

                   because they may differ from the sectors in the base image.

                   If the output is to a host device, we also write out

                   sectors that are entirely 0, since whatever data was

                   already there is garbage, not 0s. */

                if (!has_zero_init || out_baseimg ||

                    is_allocated_sectors(buf1, n, &n1)) {

                    if (bdrv_write(out_bs, sector_num, buf1, n1) < 0)

                        error("error while writing");

                }

                sector_num += n1;

                n -= n1;

                buf1 += n1 * 512;

            }

        }

    }

    qemu_free(buf);

    bdrv_delete(out_bs);

    for (bs_i = 0; bs_i < bs_n; bs_i++)

        bdrv_delete(bs[bs_i]);

    free(bs);

    return 0;

}

#ifdef _WIN32

static int64_t get_allocated_file_size(const char *filename)

{

    typedef DWORD (WINAPI * get_compressed_t)(const char *filename, DWORD *high);

    get_compressed_t get_compressed;

    struct _stati64 st;

    /* WinNT support GetCompressedFileSize to determine allocate size */

    get_compressed = (get_compressed_t) GetProcAddress(GetModuleHandle("kernel32"), "GetCompressedFileSizeA");

    if (get_compressed) {

            DWORD high, low;

            low = get_compressed(filename, &high);

            if (low != 0xFFFFFFFFlu || GetLastError() == NO_ERROR)

            return (((int64_t) high) << 32) + low;

    }

    if (_stati64(filename, &st) < 0)

        return -1;

    return st.st_size;

}

#else

static int64_t get_allocated_file_size(const char *filename)

{

    struct stat st;

    if (stat(filename, &st) < 0)

        return -1;

    return (int64_t)st.st_blocks * 512;

}

#endif

static void dump_snapshots(BlockDriverState *bs)

{

    QEMUSnapshotInfo *sn_tab, *sn;

    int nb_sns, i;

    char buf[256];

    nb_sns = bdrv_snapshot_list(bs, &sn_tab);

    if (nb_sns <= 0)

        return;

    printf("Snapshot list:\n");

    printf("%s\n", bdrv_snapshot_dump(buf, sizeof(buf), NULL));

    for(i = 0; i < nb_sns; i++) {

        sn = &sn_tab[i];

        printf("%s\n", bdrv_snapshot_dump(buf, sizeof(buf), sn));

    }

    qemu_free(sn_tab);

}

static int img_info(int argc, char **argv)

{

    int c;

    const char *filename, *fmt;

    BlockDriverState *bs;

    char fmt_name[128], size_buf[128], dsize_buf[128];

    uint64_t total_sectors;

    int64_t allocated_size;

    char backing_filename[1024];

    char backing_filename2[1024];

    BlockDriverInfo bdi;

    fmt = NULL;

    for(;;) {

        c = getopt(argc, argv, "f:h");

        if (c == -1)

            break;

        switch(c) {

        case 'h':

            help();

            break;

        case 'f':

            fmt = optarg;

            break;

        }

    }

    if (optind >= argc)

        help();

    filename = argv[optind++];

    bs = bdrv_new_open(filename, fmt, BDRV_O_FLAGS | BDRV_O_NO_BACKING);

    bdrv_get_format(bs, fmt_name, sizeof(fmt_name));

    bdrv_get_geometry(bs, &total_sectors);

    get_human_readable_size(size_buf, sizeof(size_buf), total_sectors * 512);

    allocated_size = get_allocated_file_size(filename);

    if (allocated_size < 0)

        snprintf(dsize_buf, sizeof(dsize_buf), "unavailable");

    else

        get_human_readable_size(dsize_buf, sizeof(dsize_buf),

                                allocated_size);

    printf("image: %s\n"

           "file format: %s\n"

           "virtual size: %s (%" PRId64 " bytes)\n"

           "disk size: %s\n",

           filename, fmt_name, size_buf,

           (total_sectors * 512),

           dsize_buf);

    if (bdrv_is_encrypted(bs))

        printf("encrypted: yes\n");

    if (bdrv_get_info(bs, &bdi) >= 0) {

        if (bdi.cluster_size != 0)

            printf("cluster_size: %d\n", bdi.cluster_size);

    }

    bdrv_get_backing_filename(bs, backing_filename, sizeof(backing_filename));

    if (backing_filename[0] != '\0') {

        path_combine(backing_filename2, sizeof(backing_filename2),

                     filename, backing_filename);

        printf("backing file: %s (actual path: %s)\n",

               backing_filename,

               backing_filename2);

    }

    dump_snapshots(bs);

    bdrv_delete(bs);

    return 0;

}

#define SNAPSHOT_LIST   1

#define SNAPSHOT_CREATE 2

#define SNAPSHOT_APPLY  3

#define SNAPSHOT_DELETE 4

static int img_snapshot(int argc, char **argv)

{

    BlockDriverState *bs;

    QEMUSnapshotInfo sn;

    char *filename, *snapshot_name = NULL;

    int c, ret, bdrv_oflags;

    int action = 0;

    qemu_timeval tv;

    bdrv_oflags = BDRV_O_RDWR;

    /* Parse commandline parameters */

    for(;;) {

        c = getopt(argc, argv, "la:c:d:h");

        if (c == -1)

            break;

        switch(c) {

        case 'h':

            help();

            return 0;

        case 'l':

            if (action) {

                help();

                return 0;

            }

            action = SNAPSHOT_LIST;

            bdrv_oflags &= ~BDRV_O_RDWR; /* no need for RW */

            break;

        case 'a':

            if (action) {

                help();

                return 0;

            }

            action = SNAPSHOT_APPLY;

            snapshot_name = optarg;

            break;

        case 'c':

            if (action) {

                help();

                return 0;

            }

            action = SNAPSHOT_CREATE;

            snapshot_name = optarg;

            break;

        case 'd':

            if (action) {

                help();

                return 0;

            }

            action = SNAPSHOT_DELETE;

            snapshot_name = optarg;

            break;

        }

    }

    if (optind >= argc)

        help();

    filename = argv[optind++];

    /* Open the image */

    bs = bdrv_new_open(filename, NULL, bdrv_oflags);

    /* Perform the requested action */

    switch(action) {

    case SNAPSHOT_LIST:

        dump_snapshots(bs);

        break;

    case SNAPSHOT_CREATE:

        memset(&sn, 0, sizeof(sn));

        pstrcpy(sn.name, sizeof(sn.name), snapshot_name);

        qemu_gettimeofday(&tv);

        sn.date_sec = tv.tv_sec;

        sn.date_nsec = tv.tv_usec * 1000;

        ret = bdrv_snapshot_create(bs, &sn);

        if (ret)

            error("Could not create snapshot '%s': %d (%s)",

                snapshot_name, ret, strerror(-ret));

        break;

    case SNAPSHOT_APPLY:

        ret = bdrv_snapshot_goto(bs, snapshot_name);

        if (ret)

            error("Could not apply snapshot '%s': %d (%s)",

                snapshot_name, ret, strerror(-ret));

        break;

    case SNAPSHOT_DELETE:

        ret = bdrv_snapshot_delete(bs, snapshot_name);

        if (ret)

            error("Could not delete snapshot '%s': %d (%s)",

                snapshot_name, ret, strerror(-ret));

        break;

    }

    /* Cleanup */

    bdrv_delete(bs);

    return 0;

}

static int img_rebase(int argc, char **argv)

{

    BlockDriverState *bs, *bs_old_backing, *bs_new_backing;

    BlockDriver *old_backing_drv, *new_backing_drv;

    char *filename;

    const char *fmt, *out_basefmt, *out_baseimg;

    int c, flags, ret;

    int unsafe = 0;

    /* Parse commandline parameters */

    fmt = NULL;

    out_baseimg = NULL;

    out_basefmt = NULL;

    for(;;) {

        c = getopt(argc, argv, "uhf:F:b:");

        if (c == -1)

            break;

        switch(c) {

        case 'h':

            help();

            return 0;

        case 'f':

            fmt = optarg;

            break;

        case 'F':

            out_basefmt = optarg;

            break;

        case 'b':

            out_baseimg = optarg;

            break;

        case 'u':

            unsafe = 1;

            break;

        }

    }

    if ((optind >= argc) || !out_baseimg)

        help();

    filename = argv[optind++];

    /*

     * Open the images.

     *

     * Ignore the old backing file for unsafe rebase in case we want to correct

     * the reference to a renamed or moved backing file.

     */

    flags = BDRV_O_FLAGS | BDRV_O_RDWR | (unsafe ? BDRV_O_NO_BACKING : 0);

    bs = bdrv_new_open(filename, fmt, flags);

    /* Find the right drivers for the backing files */

    old_backing_drv = NULL;

    new_backing_drv = NULL;

    if (!unsafe && bs->backing_format[0] != '\0') {

        old_backing_drv = bdrv_find_format(bs->backing_format);

        if (old_backing_drv == NULL) {

            error("Invalid format name: '%s'", bs->backing_format);

        }

    }

    if (out_basefmt != NULL) {

        new_backing_drv = bdrv_find_format(out_basefmt);

        if (new_backing_drv == NULL) {

            error("Invalid format name: '%s'", out_basefmt);

        }

    }

    /* For safe rebasing we need to compare old and new backing file */

    if (unsafe) {

        /* Make the compiler happy */

        bs_old_backing = NULL;

        bs_new_backing = NULL;

    } else {

        char backing_name[1024];

        bs_old_backing = bdrv_new("old_backing");

        bdrv_get_backing_filename(bs, backing_name, sizeof(backing_name));

        if (bdrv_open(bs_old_backing, backing_name, BDRV_O_FLAGS,

            old_backing_drv))

        {

            error("Could not open old backing file '%s'", backing_name);

            return -1;

        }

        bs_new_backing = bdrv_new("new_backing");

        if (bdrv_open(bs_new_backing, out_baseimg, BDRV_O_FLAGS | BDRV_O_RDWR,

            new_backing_drv))

        {

            error("Could not open new backing file '%s'", out_baseimg);

            return -1;

        }

    }

    /*

     * Check each unallocated cluster in the COW file. If it is unallocated,

     * accesses go to the backing file. We must therefore compare this cluster

     * in the old and new backing file, and if they differ we need to copy it

     * from the old backing file into the COW file.

     *

     * If qemu-img crashes during this step, no harm is done. The content of

     * the image is the same as the original one at any time.

     */

    if (!unsafe) {

        uint64_t num_sectors;

        uint64_t sector;

        int n;

        uint8_t * buf_old;

        uint8_t * buf_new;

        buf_old = qemu_malloc(IO_BUF_SIZE);

        buf_new = qemu_malloc(IO_BUF_SIZE);

        bdrv_get_geometry(bs, &num_sectors);

        for (sector = 0; sector < num_sectors; sector += n) {

            /* How many sectors can we handle with the next read? */

            if (sector + (IO_BUF_SIZE / 512) <= num_sectors) {

                n = (IO_BUF_SIZE / 512);

            } else {

                n = num_sectors - sector;

            }

            /* If the cluster is allocated, we don't need to take action */

            ret = bdrv_is_allocated(bs, sector, n, &n);

            if (ret) {

                continue;

            }

            /* Read old and new backing file */

            if (bdrv_read(bs_old_backing, sector, buf_old, n) < 0) {

                error("error while reading from old backing file");

            }

            if (bdrv_read(bs_new_backing, sector, buf_new, n) < 0) {

                error("error while reading from new backing file");

            }

            /* If they differ, we need to write to the COW file */

            uint64_t written = 0;

            while (written < n) {

                int pnum;

                if (compare_sectors(buf_old + written * 512,

                    buf_new + written * 512, n - written, &pnum))

                {

                    ret = bdrv_write(bs, sector + written,

                        buf_old + written * 512, pnum);

                    if (ret < 0) {

                        error("Error while writing to COW image: %s",

                            strerror(-ret));

                    }

                }

                written += pnum;

            }

        }

        qemu_free(buf_old);

        qemu_free(buf_new);

    }

    /*

     * Change the backing file. All clusters that are different from the old

     * backing file are overwritten in the COW file now, so the visible content

     * doesn't change when we switch the backing file.

     */

    ret = bdrv_change_backing_file(bs, out_baseimg, out_basefmt);

    if (ret == -ENOSPC) {

        error("Could not change the backing file to '%s': No space left in "

            "the file header", out_baseimg);

    } else if (ret < 0) {

        error("Could not change the backing file to '%s': %s",

            out_baseimg, strerror(-ret));

    }

    /*

     * TODO At this point it is possible to check if any clusters that are

     * allocated in the COW file are the same in the backing file. If so, they

     * could be dropped from the COW file. Don't do this before switching the

     * backing file, in case of a crash this would lead to corruption.

     */

    /* Cleanup */

    if (!unsafe) {

        bdrv_delete(bs_old_backing);

        bdrv_delete(bs_new_backing);

    }

    bdrv_delete(bs);

    return 0;

}

static int img_resize(int argc, char **argv)

{

    int c, ret, relative;

    const char *filename, *fmt, *size;

    int64_t n, total_size;

    BlockDriverState *bs;

    QEMUOptionParameter *param;

    QEMUOptionParameter resize_options[] = {

        {

            .name = BLOCK_OPT_SIZE,

            .type = OPT_SIZE,

            .help = "Virtual disk size"

        },

        { NULL }

    };

    fmt = NULL;

    for(;;) {

        c = getopt(argc, argv, "f:h");

        if (c == -1) {

            break;

        }

        switch(c) {

        case 'h':

            help();

            break;

        case 'f':

            fmt = optarg;

            break;

        }

    }

    if (optind + 1 >= argc) {

        help();

    }

    filename = argv[optind++];

    size = argv[optind++];

    /* Choose grow, shrink, or absolute resize mode */

    switch (size[0]) {

    case '+':

        relative = 1;

        size++;

        break;

    case '-':

        relative = -1;

        size++;

        break;

    default:

        relative = 0;

        break;

    }

    /* Parse size */

    param = parse_option_parameters("", resize_options, NULL);

    if (set_option_parameter(param, BLOCK_OPT_SIZE, size)) {

        /* Error message already printed when size parsing fails */

        exit(1);

    }

    n = get_option_parameter(param, BLOCK_OPT_SIZE)->value.n;

    free_option_parameters(param);

    bs = bdrv_new_open(filename, fmt, BDRV_O_FLAGS | BDRV_O_RDWR);

    if (relative) {

        total_size = bdrv_getlength(bs) + n * relative;