new disk image layer

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@1037 c046a42c-6fe2-441c-8c8c-71466251a162

1 files changed, 278 insertions, 0 deletions

diff --git a/block-vmdk.c b/block-vmdk.c
new file mode 100644
index 0000000..d1414e4
--- /dev/null
+++ b/block-vmdk.c
@@ -0,0 +1,278 @@
+/*
+ * Block driver for the VMDK format
+ * 
+ * Copyright (c) 2004 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 "vl.h"
+#include "block_int.h"
+
+/* XXX: this code is untested */
+/* XXX: add write support */
+
+#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];
+} VMDK4Header;
+
+#define L2_CACHE_SIZE 16
+
+typedef struct BDRVVmdkState {
+    int fd;
+    int64_t l1_table_offset;
+    uint32_t *l1_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;
+} BDRVVmdkState;
+
+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;
+}
+
+static int vmdk_open(BlockDriverState *bs, const char *filename)
+{
+    BDRVVmdkState *s = bs->opaque;
+    int fd, i;
+    uint32_t magic;
+    int l1_size;
+
+    fd = open(filename, O_RDONLY | O_BINARY | O_LARGEFILE);
+    if (fd < 0)
+        return -1;
+    if (read(fd, &magic, sizeof(magic)) != sizeof(magic))
+        goto fail;
+    magic = le32_to_cpu(magic);
+    
+    if (magic == VMDK3_MAGIC) {
+        VMDK3Header header;
+        if (read(fd, &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) * 512;
+        s->l1_entry_sectors = s->l2_size * s->cluster_sectors;
+    } else if (magic == VMDK4_MAGIC) {
+        VMDK4Header header;
+        
+        if (read(fd, &header, sizeof(header)) != sizeof(header))
+            goto fail;
+        bs->total_sectors = le32_to_cpu(header.capacity);
+        s->cluster_sectors = le32_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) * 512;
+    } else {
+        goto fail;
+    }
+    /* read the L1 table */
+    l1_size = s->l1_size * sizeof(uint32_t);
+    s->l1_table = qemu_malloc(l1_size);
+    if (!s->l1_table)
+        goto fail;
+    if (read(s->fd, s->l1_table, l1_size) != l1_size)
+        goto fail;
+    for(i = 0; i < s->l1_size; i++) {
+        le32_to_cpus(&s->l1_table[i]);
+    }
+
+    s->l2_cache = qemu_malloc(s->l2_size * L2_CACHE_SIZE * sizeof(uint32_t));
+    if (!s->l2_cache)
+        goto fail;
+    s->fd = fd;
+    /* XXX: currently only read only */
+    bs->read_only = 1;
+    return 0;
+ fail:
+    qemu_free(s->l1_table);
+    qemu_free(s->l2_cache);
+    close(fd);
+    return -1;
+}
+
+static uint64_t get_cluster_offset(BlockDriverState *bs,
+                                   uint64_t offset)
+{
+    BDRVVmdkState *s = bs->opaque;
+    unsigned int l1_index, l2_offset, l2_index;
+    int min_index, i, j;
+    uint32_t min_count, *l2_table;
+    uint64_t cluster_offset;
+    
+    l1_index = (offset >> 9) / s->l1_entry_sectors;
+    if (l1_index >= s->l1_size)
+        return 0;
+    l2_offset = s->l1_table[l1_index];
+    if (!l2_offset)
+        return 0;
+    
+    for(i = 0; i < L2_CACHE_SIZE; i++) {
+        if (l2_offset == s->l2_cache_offsets[i]) {
+            /* increment the hit count */
+            if (++s->l2_cache_counts[i] == 0xffffffff) {
+                for(j = 0; j < L2_CACHE_SIZE; j++) {
+                    s->l2_cache_counts[j] >>= 1;
+                }
+            }
+            l2_table = s->l2_cache + (i * s->l2_size);
+            goto found;
+        }
+    }
+    /* not found: load a new entry in the least used one */
+    min_index = 0;
+    min_count = 0xffffffff;
+    for(i = 0; i < L2_CACHE_SIZE; i++) {
+        if (s->l2_cache_counts[i] < min_count) {
+            min_count = s->l2_cache_counts[i];
+            min_index = i;
+        }
+    }
+    l2_table = s->l2_cache + (min_index * s->l2_size);
+    lseek(s->fd, (int64_t)l2_offset * 512, SEEK_SET);
+    if (read(s->fd, l2_table, s->l2_size * sizeof(uint32_t)) != 
+        s->l2_size * sizeof(uint32_t))
+        return 0;
+    s->l2_cache_offsets[min_index] = l2_offset;
+    s->l2_cache_counts[min_index] = 1;
+ found:
+    l2_index = ((offset >> 9) / s->cluster_sectors) % s->l2_size;
+    cluster_offset = le32_to_cpu(l2_table[l2_index]);
+    cluster_offset <<= 9;
+    return cluster_offset;
+}
+
+static int vmdk_is_allocated(BlockDriverState *bs, int64_t sector_num, 
+                             int nb_sectors, int *pnum)
+{
+    BDRVVmdkState *s = bs->opaque;
+    int index_in_cluster, n;
+    uint64_t cluster_offset;
+
+    cluster_offset = get_cluster_offset(bs, sector_num << 9);
+    index_in_cluster = sector_num % s->cluster_sectors;
+    n = s->cluster_sectors - index_in_cluster;
+    if (n > nb_sectors)
+        n = nb_sectors;
+    *pnum = n;
+    return (cluster_offset != 0);
+}
+
+static int vmdk_read(BlockDriverState *bs, int64_t sector_num, 
+                    uint8_t *buf, int nb_sectors)
+{
+    BDRVVmdkState *s = bs->opaque;
+    int ret, index_in_cluster, n;
+    uint64_t cluster_offset;
+    
+    while (nb_sectors > 0) {
+        cluster_offset = get_cluster_offset(bs, sector_num << 9);
+        index_in_cluster = sector_num % s->cluster_sectors;
+        n = s->cluster_sectors - index_in_cluster;
+        if (n > nb_sectors)
+            n = nb_sectors;
+        if (!cluster_offset) {
+            memset(buf, 0, 512 * n);
+        } else {
+            lseek64(s->fd, cluster_offset + index_in_cluster * 512, SEEK_SET);
+            ret = read(s->fd, buf, n * 512);
+            if (ret != n * 512) 
+                return -1;
+        }
+        nb_sectors -= n;
+        sector_num += n;
+        buf += n * 512;
+    }
+    return 0;
+}
+
+static int vmdk_write(BlockDriverState *bs, int64_t sector_num, 
+                     const uint8_t *buf, int nb_sectors)
+{
+    return -1;
+}
+
+static int vmdk_close(BlockDriverState *bs)
+{
+    BDRVVmdkState *s = bs->opaque;
+    qemu_free(s->l1_table);
+    qemu_free(s->l2_cache);
+    close(s->fd);
+}
+
+BlockDriver bdrv_vmdk = {
+    "vmdk",
+    sizeof(BDRVVmdkState),
+    vmdk_probe,
+    vmdk_open,
+    vmdk_read,
+    vmdk_write,
+    vmdk_close,
+    NULL, /* no create yet */
+    vmdk_is_allocated,
+};