multiple snapshot support

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@2086 c046a42c-6fe2-441c-8c8c-71466251a162

1 files changed, 478 insertions, 72 deletions

diff --git a/vl.c b/vl.c
index b31b2398a..6daed966b 100644
--- a/vl.c
+++ b/vl.c
@@ -113,7 +113,11 @@ char phys_ram_file[1024];
 void *ioport_opaque[MAX_IOPORTS];
 IOPortReadFunc *ioport_read_table[3][MAX_IOPORTS];
 IOPortWriteFunc *ioport_write_table[3][MAX_IOPORTS];
-BlockDriverState *bs_table[MAX_DISKS], *fd_table[MAX_FD];
+/* Note: bs_table[MAX_DISKS] is a dummy block driver if none available
+   to store the VM snapshots */
+BlockDriverState *bs_table[MAX_DISKS + 1], *fd_table[MAX_FD];
+/* point to the block driver where the snapshots are managed */
+BlockDriverState *bs_snapshots;
 int vga_ram_size;
 int bios_size;
 static DisplayState display_state;
@@ -4085,14 +4089,190 @@ void qemu_del_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque)
 /***********************************************************/
 /* savevm/loadvm support */
 
+#define IO_BUF_SIZE 32768
+
+struct QEMUFile {
+    FILE *outfile;
+    BlockDriverState *bs;
+    int is_file;
+    int is_writable;
+    int64_t base_offset;
+    int64_t buf_offset; /* start of buffer when writing, end of buffer
+                           when reading */
+    int buf_index;
+    int buf_size; /* 0 when writing */
+    uint8_t buf[IO_BUF_SIZE];
+};
+
+QEMUFile *qemu_fopen(const char *filename, const char *mode)
+{
+    QEMUFile *f;
+
+    f = qemu_mallocz(sizeof(QEMUFile));
+    if (!f)
+        return NULL;
+    if (!strcmp(mode, "wb")) {
+        f->is_writable = 1;
+    } else if (!strcmp(mode, "rb")) {
+        f->is_writable = 0;
+    } else {
+        goto fail;
+    }
+    f->outfile = fopen(filename, mode);
+    if (!f->outfile)
+        goto fail;
+    f->is_file = 1;
+    return f;
+ fail:
+    if (f->outfile)
+        fclose(f->outfile);
+    qemu_free(f);
+    return NULL;
+}
+
+QEMUFile *qemu_fopen_bdrv(BlockDriverState *bs, int64_t offset, int is_writable)
+{
+    QEMUFile *f;
+
+    f = qemu_mallocz(sizeof(QEMUFile));
+    if (!f)
+        return NULL;
+    f->is_file = 0;
+    f->bs = bs;
+    f->is_writable = is_writable;
+    f->base_offset = offset;
+    return f;
+}
+
+void qemu_fflush(QEMUFile *f)
+{
+    if (!f->is_writable)
+        return;
+    if (f->buf_index > 0) {
+        if (f->is_file) {
+            fseek(f->outfile, f->buf_offset, SEEK_SET);
+            fwrite(f->buf, 1, f->buf_index, f->outfile);
+        } else {
+            bdrv_pwrite(f->bs, f->base_offset + f->buf_offset, 
+                        f->buf, f->buf_index);
+        }
+        f->buf_offset += f->buf_index;
+        f->buf_index = 0;
+    }
+}
+
+static void qemu_fill_buffer(QEMUFile *f)
+{
+    int len;
+
+    if (f->is_writable)
+        return;
+    if (f->is_file) {
+        fseek(f->outfile, f->buf_offset, SEEK_SET);
+        len = fread(f->buf, 1, IO_BUF_SIZE, f->outfile);
+        if (len < 0)
+            len = 0;
+    } else {
+        len = bdrv_pread(f->bs, f->base_offset + f->buf_offset, 
+                         f->buf, IO_BUF_SIZE);
+        if (len < 0)
+            len = 0;
+    }
+    f->buf_index = 0;
+    f->buf_size = len;
+    f->buf_offset += len;
+}
+
+void qemu_fclose(QEMUFile *f)
+{
+    if (f->is_writable)
+        qemu_fflush(f);
+    if (f->is_file) {
+        fclose(f->outfile);
+    }
+    qemu_free(f);
+}
+
 void qemu_put_buffer(QEMUFile *f, const uint8_t *buf, int size)
 {
-    fwrite(buf, 1, size, f);
+    int l;
+    while (size > 0) {
+        l = IO_BUF_SIZE - f->buf_index;
+        if (l > size)
+            l = size;
+        memcpy(f->buf + f->buf_index, buf, l);
+        f->buf_index += l;
+        buf += l;
+        size -= l;
+        if (f->buf_index >= IO_BUF_SIZE)
+            qemu_fflush(f);
+    }
 }
 
 void qemu_put_byte(QEMUFile *f, int v)
 {
-    fputc(v, f);
+    f->buf[f->buf_index++] = v;
+    if (f->buf_index >= IO_BUF_SIZE)
+        qemu_fflush(f);
+}
+
+int qemu_get_buffer(QEMUFile *f, uint8_t *buf, int size1)
+{
+    int size, l;
+
+    size = size1;
+    while (size > 0) {
+        l = f->buf_size - f->buf_index;
+        if (l == 0) {
+            qemu_fill_buffer(f);
+            l = f->buf_size - f->buf_index;
+            if (l == 0)
+                break;
+        }
+        if (l > size)
+            l = size;
+        memcpy(buf, f->buf + f->buf_index, l);
+        f->buf_index += l;
+        buf += l;
+        size -= l;
+    }
+    return size1 - size;
+}
+
+int qemu_get_byte(QEMUFile *f)
+{
+    if (f->buf_index >= f->buf_size) {
+        qemu_fill_buffer(f);
+        if (f->buf_index >= f->buf_size)
+            return 0;
+    }
+    return f->buf[f->buf_index++];
+}
+
+int64_t qemu_ftell(QEMUFile *f)
+{
+    return f->buf_offset - f->buf_size + f->buf_index;
+}
+
+int64_t qemu_fseek(QEMUFile *f, int64_t pos, int whence)
+{
+    if (whence == SEEK_SET) {
+        /* nothing to do */
+    } else if (whence == SEEK_CUR) {
+        pos += qemu_ftell(f);
+    } else {
+        /* SEEK_END not supported */
+        return -1;
+    }
+    if (f->is_writable) {
+        qemu_fflush(f);
+        f->buf_offset = pos;
+    } else {
+        f->buf_offset = pos;
+        f->buf_index = 0;
+        f->buf_size = 0;
+    }
+    return pos;
 }
 
 void qemu_put_be16(QEMUFile *f, unsigned int v)
@@ -4115,21 +4295,6 @@ void qemu_put_be64(QEMUFile *f, uint64_t v)
     qemu_put_be32(f, v);
 }
 
-int qemu_get_buffer(QEMUFile *f, uint8_t *buf, int size)
-{
-    return fread(buf, 1, size, f);
-}
-
-int qemu_get_byte(QEMUFile *f)
-{
-    int v;
-    v = fgetc(f);
-    if (v == EOF)
-        return 0;
-    else
-        return v;
-}
-
 unsigned int qemu_get_be16(QEMUFile *f)
 {
     unsigned int v;
@@ -4156,18 +4321,6 @@ uint64_t qemu_get_be64(QEMUFile *f)
     return v;
 }
 
-int64_t qemu_ftell(QEMUFile *f)
-{
-    return ftell(f);
-}
-
-int64_t qemu_fseek(QEMUFile *f, int64_t pos, int whence)
-{
-    if (fseek(f, pos, whence) < 0)
-        return -1;
-    return ftell(f);
-}
-
 typedef struct SaveStateEntry {
     char idstr[256];
     int instance_id;
@@ -4209,25 +4362,18 @@ int register_savevm(const char *idstr,
 }
 
 #define QEMU_VM_FILE_MAGIC   0x5145564d
-#define QEMU_VM_FILE_VERSION 0x00000001
+#define QEMU_VM_FILE_VERSION 0x00000002
 
-int qemu_savevm(const char *filename)
+int qemu_savevm_state(QEMUFile *f)
 {
     SaveStateEntry *se;
-    QEMUFile *f;
-    int len, len_pos, cur_pos, saved_vm_running, ret;
-
-    saved_vm_running = vm_running;
-    vm_stop(0);
-
-    f = fopen(filename, "wb");
-    if (!f) {
-        ret = -1;
-        goto the_end;
-    }
+    int len, ret;
+    int64_t cur_pos, len_pos, total_len_pos;
 
     qemu_put_be32(f, QEMU_VM_FILE_MAGIC);
     qemu_put_be32(f, QEMU_VM_FILE_VERSION);
+    total_len_pos = qemu_ftell(f);
+    qemu_put_be64(f, 0); /* total size */
 
     for(se = first_se; se != NULL; se = se->next) {
         /* ID string */
@@ -4239,24 +4385,24 @@ int qemu_savevm(const char *filename)
         qemu_put_be32(f, se->version_id);
 
         /* record size: filled later */
-        len_pos = ftell(f);
+        len_pos = qemu_ftell(f);
         qemu_put_be32(f, 0);
         
         se->save_state(f, se->opaque);
 
         /* fill record size */
-        cur_pos = ftell(f);
-        len = ftell(f) - len_pos - 4;
-        fseek(f, len_pos, SEEK_SET);
+        cur_pos = qemu_ftell(f);
+        len = cur_pos - len_pos - 4;
+        qemu_fseek(f, len_pos, SEEK_SET);
         qemu_put_be32(f, len);
-        fseek(f, cur_pos, SEEK_SET);
+        qemu_fseek(f, cur_pos, SEEK_SET);
     }
+    cur_pos = qemu_ftell(f);
+    qemu_fseek(f, total_len_pos, SEEK_SET);
+    qemu_put_be64(f, cur_pos - total_len_pos - 8);
+    qemu_fseek(f, cur_pos, SEEK_SET);
 
-    fclose(f);
     ret = 0;
- the_end:
-    if (saved_vm_running)
-        vm_start();
     return ret;
 }
 
@@ -4272,38 +4418,29 @@ static SaveStateEntry *find_se(const char *idstr, int instance_id)
     return NULL;
 }
 
-int qemu_loadvm(const char *filename)
+int qemu_loadvm_state(QEMUFile *f)
 {
     SaveStateEntry *se;
-    QEMUFile *f;
-    int len, cur_pos, ret, instance_id, record_len, version_id;
-    int saved_vm_running;
+    int len, ret, instance_id, record_len, version_id;
+    int64_t total_len, end_pos, cur_pos;
     unsigned int v;
     char idstr[256];
     
-    saved_vm_running = vm_running;
-    vm_stop(0);
-
-    f = fopen(filename, "rb");
-    if (!f) {
-        ret = -1;
-        goto the_end;
-    }
-
     v = qemu_get_be32(f);
     if (v != QEMU_VM_FILE_MAGIC)
         goto fail;
     v = qemu_get_be32(f);
     if (v != QEMU_VM_FILE_VERSION) {
     fail:
-        fclose(f);
         ret = -1;
         goto the_end;
     }
+    total_len = qemu_get_be64(f);
+    end_pos = total_len + qemu_ftell(f);
     for(;;) {
-        len = qemu_get_byte(f);
-        if (feof(f))
+        if (qemu_ftell(f) >= end_pos)
             break;
+        len = qemu_get_byte(f);
         qemu_get_buffer(f, idstr, len);
         idstr[len] = '\0';
         instance_id = qemu_get_be32(f);
@@ -4313,7 +4450,7 @@ int qemu_loadvm(const char *filename)
         printf("idstr=%s instance=0x%x version=%d len=%d\n", 
                idstr, instance_id, version_id, record_len);
 #endif
-        cur_pos = ftell(f);
+        cur_pos = qemu_ftell(f);
         se = find_se(idstr, instance_id);
         if (!se) {
             fprintf(stderr, "qemu: warning: instance 0x%x of device '%s' not present in current VM\n", 
@@ -4328,12 +4465,281 @@ int qemu_loadvm(const char *filename)
         /* always seek to exact end of record */
         qemu_fseek(f, cur_pos + record_len, SEEK_SET);
     }
-    fclose(f);
     ret = 0;
  the_end:
+    return ret;
+}
+
+/* device can contain snapshots */
+static int bdrv_can_snapshot(BlockDriverState *bs)
+{
+    return (bs &&
+            !bdrv_is_removable(bs) &&
+            !bdrv_is_read_only(bs));
+}
+
+/* device must be snapshots in order to have a reliable snapshot */
+static int bdrv_has_snapshot(BlockDriverState *bs)
+{
+    return (bs &&
+            !bdrv_is_removable(bs) &&
+            !bdrv_is_read_only(bs));
+}
+
+static BlockDriverState *get_bs_snapshots(void)
+{
+    BlockDriverState *bs;
+    int i;
+
+    if (bs_snapshots)
+        return bs_snapshots;
+    for(i = 0; i <= MAX_DISKS; i++) {
+        bs = bs_table[i];
+        if (bdrv_can_snapshot(bs))
+            goto ok;
+    }
+    return NULL;
+ ok:
+    bs_snapshots = bs;
+    return bs;
+}
+
+static int bdrv_snapshot_find(BlockDriverState *bs, QEMUSnapshotInfo *sn_info,
+                              const char *name)
+{
+    QEMUSnapshotInfo *sn_tab, *sn;
+    int nb_sns, i, ret;
+    
+    ret = -ENOENT;
+    nb_sns = bdrv_snapshot_list(bs, &sn_tab);
+    if (nb_sns < 0)
+        return ret;
+    for(i = 0; i < nb_sns; i++) {
+        sn = &sn_tab[i];
+        if (!strcmp(sn->id_str, name) || !strcmp(sn->name, name)) {
+            *sn_info = *sn;
+            ret = 0;
+            break;
+        }
+    }
+    qemu_free(sn_tab);
+    return ret;
+}
+
+void do_savevm(const char *name)
+{
+    BlockDriverState *bs, *bs1;
+    QEMUSnapshotInfo sn1, *sn = &sn1, old_sn1, *old_sn = &old_sn1;
+    int must_delete, ret, i;
+    BlockDriverInfo bdi1, *bdi = &bdi1;
+    QEMUFile *f;
+    int saved_vm_running;
+    struct timeval tv;
+
+    bs = get_bs_snapshots();
+    if (!bs) {
+        term_printf("No block device can accept snapshots\n");
+        return;
+    }
+
+    saved_vm_running = vm_running;
+    vm_stop(0);
+    
+    must_delete = 0;
+    if (name) {
+        ret = bdrv_snapshot_find(bs, old_sn, name);
+        if (ret >= 0) {
+            must_delete = 1;
+        }
+    }
+    memset(sn, 0, sizeof(*sn));
+    if (must_delete) {
+        pstrcpy(sn->name, sizeof(sn->name), old_sn->name);
+        pstrcpy(sn->id_str, sizeof(sn->id_str), old_sn->id_str);
+    } else {
+        if (name)
+            pstrcpy(sn->name, sizeof(sn->name), name);
+    }
+
+    /* fill auxiliary fields */
+    gettimeofday(&tv, NULL);
+    sn->date_sec = tv.tv_sec;
+    sn->date_nsec = tv.tv_usec * 1000;
+    sn->vm_clock_nsec = qemu_get_clock(vm_clock);
+    
+    if (bdrv_get_info(bs, bdi) < 0 || bdi->vm_state_offset <= 0) {
+        term_printf("Device %s does not support VM state snapshots\n",
+                    bdrv_get_device_name(bs));
+        goto the_end;
+    }
+    
+    /* save the VM state */
+    f = qemu_fopen_bdrv(bs, bdi->vm_state_offset, 1);
+    if (!f) {
+        term_printf("Could not open VM state file\n");
+        goto the_end;
+    }
+    ret = qemu_savevm_state(f);
+    sn->vm_state_size = qemu_ftell(f);
+    qemu_fclose(f);
+    if (ret < 0) {
+        term_printf("Error %d while writing VM\n", ret);
+        goto the_end;
+    }
+    
+    /* create the snapshots */
+
+    for(i = 0; i < MAX_DISKS; i++) {
+        bs1 = bs_table[i];
+        if (bdrv_has_snapshot(bs1)) {
+            if (must_delete) {
+                ret = bdrv_snapshot_delete(bs1, old_sn->id_str);
+                if (ret < 0) {
+                    term_printf("Error while deleting snapshot on '%s'\n",
+                                bdrv_get_device_name(bs1));
+                }
+            }
+            ret = bdrv_snapshot_create(bs1, sn);
+            if (ret < 0) {
+                term_printf("Error while creating snapshot on '%s'\n",
+                            bdrv_get_device_name(bs1));
+            }
+        }
+    }
+
+ the_end:
     if (saved_vm_running)
         vm_start();
-    return ret;
+}
+
+void do_loadvm(const char *name)
+{
+    BlockDriverState *bs, *bs1;
+    BlockDriverInfo bdi1, *bdi = &bdi1;
+    QEMUFile *f;
+    int i, ret;
+    int saved_vm_running;
+
+    bs = get_bs_snapshots();
+    if (!bs) {
+        term_printf("No block device supports snapshots\n");
+        return;
+    }
+    
+    saved_vm_running = vm_running;
+    vm_stop(0);
+
+    for(i = 0; i <= MAX_DISKS; i++) {
+        bs1 = bs_table[i];
+        if (bdrv_has_snapshot(bs1)) {
+            ret = bdrv_snapshot_goto(bs1, name);
+            if (ret < 0) {
+                if (bs != bs1)
+                    term_printf("Warning: ");
+                switch(ret) {
+                case -ENOTSUP:
+                    term_printf("Snapshots not supported on device '%s'\n",
+                                bdrv_get_device_name(bs1));
+                    break;
+                case -ENOENT:
+                    term_printf("Could not find snapshot '%s' on device '%s'\n",
+                                name, bdrv_get_device_name(bs1));
+                    break;
+                default:
+                    term_printf("Error %d while activating snapshot on '%s'\n",
+                                ret, bdrv_get_device_name(bs1));
+                    break;
+                }
+                /* fatal on snapshot block device */
+                if (bs == bs1)
+                    goto the_end;
+            }
+        }
+    }
+
+    if (bdrv_get_info(bs, bdi) < 0 || bdi->vm_state_offset <= 0) {
+        term_printf("Device %s does not support VM state snapshots\n",
+                    bdrv_get_device_name(bs));
+        return;
+    }
+    
+    /* restore the VM state */
+    f = qemu_fopen_bdrv(bs, bdi->vm_state_offset, 0);
+    if (!f) {
+        term_printf("Could not open VM state file\n");
+        goto the_end;
+    }
+    ret = qemu_loadvm_state(f);
+    qemu_fclose(f);
+    if (ret < 0) {
+        term_printf("Error %d while loading VM state\n", ret);
+    }
+ the_end:
+    if (saved_vm_running)
+        vm_start();
+}
+
+void do_delvm(const char *name)
+{
+    BlockDriverState *bs, *bs1;
+    int i, ret;
+
+    bs = get_bs_snapshots();
+    if (!bs) {
+        term_printf("No block device supports snapshots\n");
+        return;
+    }
+    
+    for(i = 0; i <= MAX_DISKS; i++) {
+        bs1 = bs_table[i];
+        if (bdrv_has_snapshot(bs1)) {
+            ret = bdrv_snapshot_delete(bs1, name);
+            if (ret < 0) {
+                if (ret == -ENOTSUP)
+                    term_printf("Snapshots not supported on device '%s'\n",
+                                bdrv_get_device_name(bs1));
+                else
+                    term_printf("Error %d while deleting snapshot on '%s'\n",
+                                ret, bdrv_get_device_name(bs1));
+            }
+        }
+    }
+}
+
+void do_info_snapshots(void)
+{
+    BlockDriverState *bs, *bs1;
+    QEMUSnapshotInfo *sn_tab, *sn;
+    int nb_sns, i;
+    char buf[256];
+
+    bs = get_bs_snapshots();
+    if (!bs) {
+        term_printf("No available block device supports snapshots\n");
+        return;
+    }
+    term_printf("Snapshot devices:");
+    for(i = 0; i <= MAX_DISKS; i++) {
+        bs1 = bs_table[i];
+        if (bdrv_has_snapshot(bs1)) {
+            if (bs == bs1)
+                term_printf(" %s", bdrv_get_device_name(bs1));
+        }
+    }
+    term_printf("\n");
+
+    nb_sns = bdrv_snapshot_list(bs, &sn_tab);
+    if (nb_sns < 0) {
+        term_printf("bdrv_snapshot_list: error %d\n", nb_sns);
+        return;
+    }
+    term_printf("Snapshot list (from %s):\n", bdrv_get_device_name(bs));
+    term_printf("%s\n", bdrv_snapshot_dump(buf, sizeof(buf), NULL));
+    for(i = 0; i < nb_sns; i++) {
+        sn = &sn_tab[i];
+        term_printf("%s\n", bdrv_snapshot_dump(buf, sizeof(buf), sn));
+    }
+    qemu_free(sn_tab);
 }
 
 /***********************************************************/
@@ -6284,7 +6690,7 @@ int main(int argc, char **argv)
     } else 
 #endif
     if (loadvm)
-        qemu_loadvm(loadvm);
+        do_loadvm(loadvm);
 
     {
         /* XXX: simplify init */