qemu-img.c

qemu虚拟机代码

        if (*p == 'M') {
            size *= 1024 * 1024;
        } else if (*p == 'G') {
            size *= 1024 * 1024 * 1024;
        } else if (*p == 'k' || *p == 'K' || *p == '\0') {
            size *= 1024;
        } else {
            help();
        }
    }
    drv = bdrv_find_format(fmt);
    if (!drv)
        error("Unknown file format '%s'", fmt);
    printf("Formating '%s', fmt=%s",
           filename, fmt);
    if (encrypted)
        printf(", encrypted");
    if (base_filename) {
        printf(", backing_file=%s",
               base_filename);
    }
    printf(", size=%lld kB\n", (long long) (size / 1024));
    ret = bdrv_create(drv, filename, size / 512, base_filename, encrypted);
    if (ret < 0) {
        if (ret == -ENOTSUP) {
            error("Formatting or formatting option not supported for file format '%s'", fmt);
        } else {
            error("Error while formatting");
        }
    }
    return 0;
}

static int img_commit(int argc, char **argv)
{
    int c, ret;
    const char *filename, *fmt;
    BlockDriver *drv;
    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("");
    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_open2(bs, filename, 0, drv) < 0) {
        error("Could not open '%s'", filename);
    }
    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;
}

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;
}

#define IO_BUF_SIZE 65536

static int img_convert(int argc, char **argv)
{
    int c, ret, n, n1, compress, cluster_size, cluster_sectors, encrypt;
    const char *filename, *fmt, *out_fmt, *out_filename;
    BlockDriver *drv;
    BlockDriverState *bs, *out_bs;
    int64_t total_sectors, nb_sectors, sector_num;
    uint8_t buf[IO_BUF_SIZE];
    const uint8_t *buf1;

    fmt = NULL;
    out_fmt = "raw";
    compress = 0;
    encrypt = 0;
    for(;;) {
        c = getopt(argc, argv, "f:O:hce");
        if (c == -1)
            break;
        switch(c) {
        case 'h':
            help();
            break;
        case 'f':
            fmt = optarg;
            break;
        case 'O':
            out_fmt = optarg;
            break;
        case 'c':
            compress = 1;
            break;
        case 'e':
            encrypt = 1;
            break;
        }
    }
    if (optind >= argc) 
        help();
    filename = argv[optind++];
    if (optind >= argc) 
        help();
    out_filename = argv[optind++];
    
    bs = bdrv_new_open(filename, fmt);

    drv = bdrv_find_format(out_fmt);
    if (!drv)
        error("Unknown file format '%s'", fmt);
    if (compress && drv != &bdrv_qcow)
        error("Compression not supported for this file format");
    if (encrypt && drv != &bdrv_qcow)
        error("Encryption not supported for this file format");
    if (compress && encrypt)
        error("Compression and encryption not supported at the same time");
    bdrv_get_geometry(bs, &total_sectors);
    ret = bdrv_create(drv, out_filename, total_sectors, NULL, encrypt);
    if (ret < 0) {
        if (ret == -ENOTSUP) {
            error("Formatting not supported for file format '%s'", fmt);
        } else {
            error("Error while formatting '%s'", out_filename);
        }
    }
    
    out_bs = bdrv_new_open(out_filename, out_fmt);

    if (compress) {
        cluster_size = qcow_get_cluster_size(out_bs);
        if (cluster_size <= 0 || cluster_size > IO_BUF_SIZE)
            error("invalid cluster size");
        cluster_sectors = cluster_size >> 9;
        sector_num = 0;
        for(;;) {
            nb_sectors = total_sectors - sector_num;
            if (nb_sectors <= 0)
                break;
            if (nb_sectors >= cluster_sectors)
                n = cluster_sectors;
            else
                n = nb_sectors;
            if (bdrv_read(bs, sector_num, buf, n) < 0) 
                error("error while reading");
            if (n < cluster_sectors)
                memset(buf + n * 512, 0, cluster_size - n * 512);
            if (is_not_zero(buf, cluster_size)) {
                if (qcow_compress_cluster(out_bs, sector_num, buf) != 0)
                    error("error while compressing sector %lld", sector_num);
            }
            sector_num += n;
        }
    } else {
        sector_num = 0;
        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;
            if (bdrv_read(bs, sector_num, 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 (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;
            }
        }
    }
    bdrv_delete(out_bs);
    bdrv_delete(bs);
    return 0;
}

#ifdef _WIN32
static int64_t get_allocated_file_size(const char *filename)
{
    struct _stati64 st;
    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 int img_info(int argc, char **argv)
{
    int c;
    const char *filename, *fmt;
    BlockDriver *drv;
    BlockDriverState *bs;
    char fmt_name[128], size_buf[128], dsize_buf[128];
    int64_t total_sectors, allocated_size;

    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("");
    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_open2(bs, filename, 0, drv) < 0) {
        error("Could not open '%s'", filename);
    }
    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)
	sprintf(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 (%lld bytes)\n"
           "disk size: %s\n",
           filename, fmt_name, size_buf, 
           (long long) (total_sectors * 512),
           dsize_buf);
    if (bdrv_is_encrypted(bs))
        printf("encrypted: yes\n");
    bdrv_delete(bs);
    return 0;
}

int main(int argc, char **argv)
{
    const char *cmd;

    bdrv_init();
    if (argc < 2)
        help();
    cmd = argv[1];
    optind++;
    if (!strcmp(cmd, "create")) {
        img_create(argc, argv);
    } else if (!strcmp(cmd, "commit")) {
        img_commit(argc, argv);
    } else if (!strcmp(cmd, "convert")) {
        img_convert(argc, argv);
    } else if (!strcmp(cmd, "info")) {
        img_info(argc, argv);
    } else {
        help();
    }
    return 0;
}