block-vmdk.c.svn-base

我们自己开发的一个OSEK操作系统！不知道可不可以？

/*
 * Block driver for the VMDK format
 *
 * Copyright (c) 2004 Fabrice Bellard
 * Copyright (c) 2005 Filip Navara
 *
 * 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 "block_int.h"

#define VMDK3_MAGIC (('C' << 24) | ('O' << 16) | ('W' << 8) | 'D')
#define VMDK4_MAGIC (('K' << 24) | ('D' << 16) | ('M' << 8) | 'V')

typedef struct {
    uint32_t version;
    uint32_t flags;
    uint32_t disk_sectors;
    uint32_t granularity;
    uint32_t l1dir_offset;
    uint32_t l1dir_size;
    uint32_t file_sectors;
    uint32_t cylinders;
    uint32_t heads;
    uint32_t sectors_per_track;
} VMDK3Header;

typedef struct {
    uint32_t version;
    uint32_t flags;
    int64_t capacity;
    int64_t granularity;
    int64_t desc_offset;
    int64_t desc_size;
    int32_t num_gtes_per_gte;
    int64_t rgd_offset;
    int64_t gd_offset;
    int64_t grain_offset;
    char filler[1];
    char check_bytes[4];
} __attribute__((packed)) VMDK4Header;

#define L2_CACHE_SIZE 16

typedef struct BDRVVmdkState {
    BlockDriverState *hd;
    int64_t l1_table_offset;
    int64_t l1_backup_table_offset;
    uint32_t *l1_table;
    uint32_t *l1_backup_table;
    unsigned int l1_size;
    uint32_t l1_entry_sectors;

    unsigned int l2_size;
    uint32_t *l2_cache;
    uint32_t l2_cache_offsets[L2_CACHE_SIZE];
    uint32_t l2_cache_counts[L2_CACHE_SIZE];

    unsigned int cluster_sectors;
    uint32_t parent_cid;
    int is_parent;
} BDRVVmdkState;

typedef struct VmdkMetaData {
    uint32_t offset;
    unsigned int l1_index;
    unsigned int l2_index;
    unsigned int l2_offset;
    int valid;
} VmdkMetaData;

typedef struct ActiveBDRVState{
    BlockDriverState *hd;            // active image handler
    uint64_t cluster_offset;         // current write offset
}ActiveBDRVState;

static ActiveBDRVState activeBDRV;


static int vmdk_probe(const uint8_t *buf, int buf_size, const char *filename)
{
    uint32_t magic;

    if (buf_size < 4)
        return 0;
    magic = be32_to_cpu(*(uint32_t *)buf);
    if (magic == VMDK3_MAGIC ||
        magic == VMDK4_MAGIC)
        return 100;
    else
        return 0;
}

#define CHECK_CID 1

#define SECTOR_SIZE 512
#define DESC_SIZE 20*SECTOR_SIZE	// 20 sectors of 512 bytes each
#define HEADER_SIZE 512   			// first sector of 512 bytes

static uint32_t vmdk_read_cid(BlockDriverState *bs, int parent)
{
    BDRVVmdkState *s = bs->opaque;
    char desc[DESC_SIZE];
    uint32_t cid;
    char *p_name, *cid_str;
    size_t cid_str_size;

    /* the descriptor offset = 0x200 */
    if (bdrv_pread(s->hd, 0x200, desc, DESC_SIZE) != DESC_SIZE)
        return 0;

    if (parent) {
        cid_str = "parentCID";
        cid_str_size = sizeof("parentCID");
    } else {
        cid_str = "CID";
        cid_str_size = sizeof("CID");
    }

    if ((p_name = strstr(desc,cid_str)) != 0) {
        p_name += cid_str_size;
        sscanf(p_name,"%x",&cid);
    }

    return cid;
}

static int vmdk_write_cid(BlockDriverState *bs, uint32_t cid)
{
    BDRVVmdkState *s = bs->opaque;
    char desc[DESC_SIZE], tmp_desc[DESC_SIZE];
    char *p_name, *tmp_str;

    /* the descriptor offset = 0x200 */
    if (bdrv_pread(s->hd, 0x200, desc, DESC_SIZE) != DESC_SIZE)
        return -1;

    tmp_str = strstr(desc,"parentCID");
    strcpy(tmp_desc, tmp_str);
    if ((p_name = strstr(desc,"CID")) != 0) {
        p_name += sizeof("CID");
        sprintf(p_name,"%x\n",cid);
        strcat(desc,tmp_desc);
    }

    if (bdrv_pwrite(s->hd, 0x200, desc, DESC_SIZE) != DESC_SIZE)
        return -1;
    return 0;
}

static int vmdk_is_cid_valid(BlockDriverState *bs)
{
#ifdef CHECK_CID
    BDRVVmdkState *s = bs->opaque;
    BlockDriverState *p_bs = s->hd->backing_hd;
    uint32_t cur_pcid;

    if (p_bs) {
        cur_pcid = vmdk_read_cid(p_bs,0);
        if (s->parent_cid != cur_pcid)
            // CID not valid
            return 0;
    }
#endif
    // CID valid
    return 1;
}

static int vmdk_snapshot_create(const char *filename, const char *backing_file)
{
    int snp_fd, p_fd;
    uint32_t p_cid;
    char *p_name, *gd_buf, *rgd_buf;
    const char *real_filename, *temp_str;
    VMDK4Header header;
    uint32_t gde_entries, gd_size;
    int64_t gd_offset, rgd_offset, capacity, gt_size;
    char p_desc[DESC_SIZE], s_desc[DESC_SIZE], hdr[HEADER_SIZE];
    char *desc_template =
    "# Disk DescriptorFile\n"
    "version=1\n"
    "CID=%x\n"
    "parentCID=%x\n"
    "createType=\"monolithicSparse\"\n"
    "parentFileNameHint=\"%s\"\n"
    "\n"
    "# Extent description\n"
    "RW %lu SPARSE \"%s\"\n"
    "\n"
    "# The Disk Data Base \n"
    "#DDB\n"
    "\n";

    snp_fd = open(filename, O_RDWR | O_CREAT | O_TRUNC | O_BINARY | O_LARGEFILE, 0644);
    if (snp_fd < 0)
        return -1;
    p_fd = open(backing_file, O_RDONLY | O_BINARY | O_LARGEFILE);
    if (p_fd < 0) {
        close(snp_fd);
        return -1;
    }

    /* read the header */
    if (lseek(p_fd, 0x0, SEEK_SET) == -1)
        goto fail;
    if (read(p_fd, hdr, HEADER_SIZE) != HEADER_SIZE)
        goto fail;

    /* write the header */
    if (lseek(snp_fd, 0x0, SEEK_SET) == -1)
        goto fail;
    if (write(snp_fd, hdr, HEADER_SIZE) == -1)
        goto fail;

    memset(&header, 0, sizeof(header));
    memcpy(&header,&hdr[4], sizeof(header)); // skip the VMDK4_MAGIC

    ftruncate(snp_fd, header.grain_offset << 9);
    /* the descriptor offset = 0x200 */
    if (lseek(p_fd, 0x200, SEEK_SET) == -1)
        goto fail;
    if (read(p_fd, p_desc, DESC_SIZE) != DESC_SIZE)
        goto fail;

    if ((p_name = strstr(p_desc,"CID")) != 0) {
        p_name += sizeof("CID");
        sscanf(p_name,"%x",&p_cid);
    }

    real_filename = filename;
    if ((temp_str = strrchr(real_filename, '\\')) != NULL)
        real_filename = temp_str + 1;
    if ((temp_str = strrchr(real_filename, '/')) != NULL)
        real_filename = temp_str + 1;
    if ((temp_str = strrchr(real_filename, ':')) != NULL)
        real_filename = temp_str + 1;

    sprintf(s_desc, desc_template, p_cid, p_cid, backing_file
            , (uint32_t)header.capacity, real_filename);

    /* write the descriptor */
    if (lseek(snp_fd, 0x200, SEEK_SET) == -1)
        goto fail;
    if (write(snp_fd, s_desc, strlen(s_desc)) == -1)
        goto fail;

    gd_offset = header.gd_offset * SECTOR_SIZE;     // offset of GD table
    rgd_offset = header.rgd_offset * SECTOR_SIZE;   // offset of RGD table
    capacity = header.capacity * SECTOR_SIZE;       // Extent size
    /*
     * Each GDE span 32M disk, means:
     * 512 GTE per GT, each GTE points to grain
     */
    gt_size = (int64_t)header.num_gtes_per_gte * header.granularity * SECTOR_SIZE;
    if (!gt_size)
        goto fail;
    gde_entries = (uint32_t)(capacity / gt_size);  // number of gde/rgde
    gd_size = gde_entries * sizeof(uint32_t);

    /* write RGD */
    rgd_buf = qemu_malloc(gd_size);
    if (!rgd_buf)
        goto fail;
    if (lseek(p_fd, rgd_offset, SEEK_SET) == -1)
        goto fail_rgd;
    if (read(p_fd, rgd_buf, gd_size) != gd_size)
        goto fail_rgd;
    if (lseek(snp_fd, rgd_offset, SEEK_SET) == -1)
        goto fail_rgd;
    if (write(snp_fd, rgd_buf, gd_size) == -1)
        goto fail_rgd;
    qemu_free(rgd_buf);

    /* write GD */
    gd_buf = qemu_malloc(gd_size);
    if (!gd_buf)
        goto fail_rgd;
    if (lseek(p_fd, gd_offset, SEEK_SET) == -1)
        goto fail_gd;
    if (read(p_fd, gd_buf, gd_size) != gd_size)
        goto fail_gd;
    if (lseek(snp_fd, gd_offset, SEEK_SET) == -1)
        goto fail_gd;
    if (write(snp_fd, gd_buf, gd_size) == -1)
        goto fail_gd;
    qemu_free(gd_buf);

    close(p_fd);
    close(snp_fd);
    return 0;

    fail_gd:
    qemu_free(gd_buf);
    fail_rgd:
    qemu_free(rgd_buf);
    fail:
    close(p_fd);
    close(snp_fd);
    return -1;
}

static void vmdk_parent_close(BlockDriverState *bs)
{
    if (bs->backing_hd)
        bdrv_close(bs->backing_hd);
}

int parent_open = 0;
static int vmdk_parent_open(BlockDriverState *bs, const char * filename)
{
    BDRVVmdkState *s = bs->opaque;
    char *p_name;
    char desc[DESC_SIZE];
    char parent_img_name[1024];

    /* the descriptor offset = 0x200 */
    if (bdrv_pread(s->hd, 0x200, desc, DESC_SIZE) != DESC_SIZE)
        return -1;

    if ((p_name = strstr(desc,"parentFileNameHint")) != 0) {
        char *end_name;
        struct stat file_buf;

        p_name += sizeof("parentFileNameHint") + 1;
        if ((end_name = strchr(p_name,'\"')) == 0)
            return -1;

        strncpy(s->hd->backing_file, p_name, end_name - p_name);
        if (stat(s->hd->backing_file, &file_buf) != 0) {
            path_combine(parent_img_name, sizeof(parent_img_name),
                         filename, s->hd->backing_file);
        } else {
            strcpy(parent_img_name, s->hd->backing_file);
        }

        s->hd->backing_hd = bdrv_new("");
        if (!s->hd->backing_hd) {
            failure:
            bdrv_close(s->hd);
            return -1;
        }
        parent_open = 1;
        if (bdrv_open(s->hd->backing_hd, parent_img_name, BDRV_O_RDONLY) < 0)
            goto failure;
        parent_open = 0;
    }

    return 0;
}

static int vmdk_open(BlockDriverState *bs, const char *filename, int flags)
{
    BDRVVmdkState *s = bs->opaque;
    uint32_t magic;
    int l1_size, i, ret;

    if (parent_open)
        // Parent must be opened as RO.
        flags = BDRV_O_RDONLY;
    fprintf(stderr, "(VMDK) image open: flags=0x%x filename=%s\n", flags, bs->filename);

    ret = bdrv_file_open(&s->hd, filename, flags);
    if (ret < 0)
        return ret;
    if (bdrv_pread(s->hd, 0, &magic, sizeof(magic)) != sizeof(magic))
        goto fail;

    magic = be32_to_cpu(magic);
    if (magic == VMDK3_MAGIC) {
        VMDK3Header header;

        if (bdrv_pread(s->hd, sizeof(magic), &header, sizeof(header)) != sizeof(header))
            goto fail;
        s->cluster_sectors = le32_to_cpu(header.granularity);
        s->l2_size = 1 << 9;
        s->l1_size = 1 << 6;
        bs->total_sectors = le32_to_cpu(header.disk_sectors);
        s->l1_table_offset = le32_to_cpu(header.l1dir_offset) << 9;
        s->l1_backup_table_offset = 0;
        s->l1_entry_sectors = s->l2_size * s->cluster_sectors;
    } else if (magic == VMDK4_MAGIC) {
        VMDK4Header header;

        if (bdrv_pread(s->hd, sizeof(magic), &header, sizeof(header)) != sizeof(header))
            goto fail;
        bs->total_sectors = le64_to_cpu(header.capacity);
        s->cluster_sectors = le64_to_cpu(header.granularity);
        s->l2_size = le32_to_cpu(header.num_gtes_per_gte);
        s->l1_entry_sectors = s->l2_size * s->cluster_sectors;
        if (s->l1_entry_sectors <= 0)
            goto fail;
        s->l1_size = (bs->total_sectors + s->l1_entry_sectors - 1)
            / s->l1_entry_sectors;
        s->l1_table_offset = le64_to_cpu(header.rgd_offset) << 9;
        s->l1_backup_table_offset = le64_to_cpu(header.gd_offset) << 9;

        if (parent_open)
            s->is_parent = 1;
        else