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-rw-r--r--lib/ext2fs/qcow2.c272
1 files changed, 272 insertions, 0 deletions
diff --git a/lib/ext2fs/qcow2.c b/lib/ext2fs/qcow2.c
new file mode 100644
index 0000000..2082417
--- /dev/null
+++ b/lib/ext2fs/qcow2.c
@@ -0,0 +1,272 @@
+/*
+ * qcow2.c --- Functions to generate qcow2 formatted disk images. This
+ * format is used originally by QEMU for virtual machines, and stores the
+ * filesystem data on disk in a packed format to avoid creating sparse
+ * image files that need lots of seeking to read and write.
+ *
+ * The qcow2 format supports zlib compression, but that is not yet
+ * implemented.
+ *
+ * It is possible to directly mount a qcow2 image using qemu-nbd:
+ *
+ * [root]# modprobe nbd max_part=63
+ * [root]# qemu-nbd -c /dev/nbd0 image.img
+ * [root]# mount /dev/nbd0p1 /mnt/qemu
+ *
+ * Format details at http://people.gnome.org/~markmc/qcow-image-format.html
+ *
+ * Copyright (C) 2010 Red Hat, Inc., Lukas Czerner <lczerner@redhat.com>
+ *
+ * %Begin-Header%
+ * This file may be redistributed under the terms of the GNU Public
+ * License.
+ * %End-Header%
+ */
+
+#ifndef _LARGEFILE_SOURCE
+#define _LARGEFILE_SOURCE
+#endif
+#ifndef _LARGEFILE64_SOURCE
+#define _LARGEFILE64_SOURCE
+#endif
+
+#include "config.h"
+#include <fcntl.h>
+#include <grp.h>
+#include <pwd.h>
+#include <stdio.h>
+#ifdef HAVE_STDLIB_H
+#include <stdlib.h>
+#endif
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <assert.h>
+
+#include "ext2fs/ext2fs.h"
+#include "qcow2.h"
+
+/* Functions for converting qcow2 image into raw image */
+
+struct ext2_qcow2_hdr *qcow2_read_header(int fd)
+{
+ void *buffer = NULL;
+ struct ext2_qcow2_hdr *hdr = NULL;
+ size_t size;
+ errcode_t ret;
+
+ ret = ext2fs_get_mem(sizeof(struct ext2_qcow2_hdr), &buffer);
+ if (ret)
+ return NULL;
+ memset(buffer, 0, sizeof(struct ext2_qcow2_hdr));
+
+ if (ext2fs_llseek(fd, 0, SEEK_SET < 0)) {
+ ext2fs_free_mem(&buffer);
+ return NULL;
+ }
+
+ size = read(fd, buffer, sizeof(struct ext2_qcow2_hdr));
+ if (size != sizeof(struct ext2_qcow2_hdr)) {
+ ext2fs_free_mem(&buffer);
+ return NULL;
+ }
+
+ hdr = (struct ext2_qcow2_hdr *)(buffer);
+
+ if ((ext2fs_be32_to_cpu(hdr->magic) != QCOW_MAGIC) ||
+ (ext2fs_be32_to_cpu(hdr->version) != 2)) {
+ ext2fs_free_mem(&hdr);
+ return NULL;
+ }
+
+ return hdr;
+}
+
+static int qcow2_read_l1_table(struct ext2_qcow2_image *img)
+{
+ int fd = img->fd;
+ size_t size, l1_size = img->l1_size * sizeof(blk64_t);
+ blk64_t *table;
+ errcode_t ret;
+
+ ret = ext2fs_get_memzero(l1_size, &table);
+ if (ret)
+ return ret;
+
+ if (ext2fs_llseek(fd, img->l1_offset, SEEK_SET) < 0) {
+ ext2fs_free_mem(&table);
+ return errno;
+ }
+
+ size = read(fd, table, l1_size);
+ if (size != l1_size) {
+ ext2fs_free_mem(&table);
+ return errno;
+ }
+
+ img->l1_table = table;
+
+ return 0;
+}
+
+static int qcow2_read_l2_table(struct ext2_qcow2_image *img,
+ __u64 offset, blk64_t **l2_table)
+{
+ int fd = img->fd;
+ size_t size;
+
+ assert(*l2_table);
+
+ if (ext2fs_llseek(fd, offset, SEEK_SET) < 0)
+ return errno;
+
+ size = read(fd, *l2_table, img->cluster_size);
+ if (size != img->cluster_size)
+ return errno;
+
+ return 0;
+}
+
+static int qcow2_copy_data(int fdin, int fdout, __u64 off_in,
+ __u64 off_out, void *buf, size_t count)
+{
+ size_t size;
+
+ assert(buf);
+
+ if (ext2fs_llseek(fdout, off_out, SEEK_SET) < 0)
+ return errno;
+
+ if (ext2fs_llseek(fdin, off_in, SEEK_SET) < 0)
+ return errno;
+
+ size = read(fdin, buf, count);
+ if (size != count)
+ return errno;
+
+ size = write(fdout, buf, count);
+ if (size != count)
+ return errno;
+
+ return 0;
+}
+
+
+int qcow2_write_raw_image(int qcow2_fd, int raw_fd,
+ struct ext2_qcow2_hdr *hdr)
+{
+ struct ext2_qcow2_image img;
+ errcode_t ret = 0;
+ unsigned int l1_index, l2_index;
+ __u64 offset;
+ blk64_t *l1_table, *l2_table = NULL;
+ void *copy_buf = NULL;
+ size_t size;
+ unsigned int max_l1_size;
+
+ if (hdr->crypt_method)
+ return -QCOW_ENCRYPTED;
+
+ img.fd = qcow2_fd;
+ img.hdr = hdr;
+ img.l2_cache = NULL;
+ img.l1_table = NULL;
+ img.cluster_bits = ext2fs_be32_to_cpu(hdr->cluster_bits);
+ if (img.cluster_bits < 9 || img.cluster_bits > 31)
+ return -QCOW_CORRUPTED;
+ img.cluster_size = 1 << img.cluster_bits;
+ img.l1_size = ext2fs_be32_to_cpu(hdr->l1_size);
+ img.l1_offset = ext2fs_be64_to_cpu(hdr->l1_table_offset);
+ img.l2_size = 1 << (img.cluster_bits - 3);
+ img.image_size = ext2fs_be64_to_cpu(hdr->size);
+
+ if (img.l1_offset & (img.cluster_size - 1))
+ return -QCOW_CORRUPTED;
+
+ max_l1_size = (img.image_size >> ((2 * img.cluster_bits) - 3)) +
+ img.cluster_size;
+ if (img.l1_size > max_l1_size)
+ return -QCOW_CORRUPTED;
+
+ ret = ext2fs_get_memzero(img.cluster_size, &l2_table);
+ if (ret)
+ goto out;
+
+ ret = ext2fs_get_memzero(1 << img.cluster_bits, &copy_buf);
+ if (ret)
+ goto out;
+
+ if (ext2fs_llseek(raw_fd, 0, SEEK_SET) < 0) {
+ ret = errno;
+ goto out;
+ }
+
+ ret = qcow2_read_l1_table(&img);
+ if (ret)
+ goto out;
+
+ l1_table = img.l1_table;
+ /* Walk through l1 table */
+ for (l1_index = 0; l1_index < img.l1_size; l1_index++) {
+ __u64 off_out;
+
+ offset = ext2fs_be64_to_cpu(l1_table[l1_index]) &
+ ~QCOW_OFLAG_COPIED;
+
+ if ((offset > img.image_size) ||
+ (offset <= 0))
+ continue;
+
+ if (offset & QCOW_OFLAG_COMPRESSED) {
+ ret = -QCOW_COMPRESSED;
+ goto out;
+ }
+
+ ret = qcow2_read_l2_table(&img, offset, &l2_table);
+ if (ret)
+ break;
+
+ /* Walk through l2 table and copy data blocks into raw image */
+ for (l2_index = 0; l2_index < img.l2_size; l2_index++) {
+ offset = ext2fs_be64_to_cpu(l2_table[l2_index]) &
+ ~QCOW_OFLAG_COPIED;
+
+ if (offset == 0)
+ continue;
+
+ off_out = ((__u64)l1_index * img.l2_size) +
+ l2_index;
+ off_out <<= img.cluster_bits;
+ ret = qcow2_copy_data(qcow2_fd, raw_fd, offset,
+ off_out, copy_buf, img.cluster_size);
+ if (ret)
+ goto out;
+ }
+ }
+
+ /* Resize the output image to the filesystem size */
+ if (ext2fs_llseek(raw_fd, img.image_size - 1, SEEK_SET) < 0) {
+ ret = errno;
+ goto out;
+ }
+
+ ((char *)copy_buf)[0] = 0;
+ size = write(raw_fd, copy_buf, 1);
+ if (size != 1) {
+ ret = errno;
+ goto out;
+ }
+
+out:
+ if (copy_buf)
+ ext2fs_free_mem(&copy_buf);
+ if (img.l1_table)
+ ext2fs_free_mem(&img.l1_table);
+ if (l2_table)
+ ext2fs_free_mem(&l2_table);
+ return ret;
+}