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#include <errno.h>
#include <sys/types.h>
#include <unistd.h>
#include "qcow2.h"
#include "tools-util.h"
#define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb)
#define QCOW_VERSION 2
#define QCOW_OFLAG_COPIED (1LL << 63)
struct qcow2_hdr {
u32 magic;
u32 version;
u64 backing_file_offset;
u32 backing_file_size;
u32 block_bits;
u64 size;
u32 crypt_method;
u32 l1_size;
u64 l1_table_offset;
u64 refcount_table_offset;
u32 refcount_table_blocks;
u32 nb_snapshots;
u64 snapshots_offset;
};
struct qcow2_image {
int fd;
u32 block_size;
u64 *l1_table;
u64 l1_offset;
u32 l1_index;
u64 *l2_table;
u64 offset;
};
static void flush_l2(struct qcow2_image *img)
{
if (img->l1_index != -1) {
img->l1_table[img->l1_index] =
cpu_to_be64(img->offset|QCOW_OFLAG_COPIED);
xpwrite(img->fd, img->l2_table, img->block_size, img->offset);
img->offset += img->block_size;
memset(img->l2_table, 0, img->block_size);
img->l1_index = -1;
}
}
static void add_l2(struct qcow2_image *img, u64 src_blk, u64 dst_offset)
{
unsigned l2_size = img->block_size / sizeof(u64);
u64 l1_index = src_blk / l2_size;
u64 l2_index = src_blk & (l2_size - 1);
if (img->l1_index != l1_index) {
flush_l2(img);
img->l1_index = l1_index;
}
img->l2_table[l2_index] = cpu_to_be64(dst_offset|QCOW_OFLAG_COPIED);
}
void qcow2_write_image(int infd, int outfd, ranges *data,
unsigned block_size)
{
u64 image_size = get_size(NULL, infd);
unsigned l2_size = block_size / sizeof(u64);
unsigned l1_size = DIV_ROUND_UP(image_size, (u64) block_size * l2_size);
struct qcow2_hdr hdr = { 0 };
struct qcow2_image img = {
.fd = outfd,
.block_size = block_size,
.l2_table = xcalloc(l2_size, sizeof(u64)),
.l1_table = xcalloc(l1_size, sizeof(u64)),
.l1_index = -1,
.offset = round_up(sizeof(hdr), block_size),
};
struct range *r;
char *buf = xmalloc(block_size);
u64 src_offset, dst_offset;
assert(is_power_of_2(block_size));
ranges_roundup(data, block_size);
ranges_sort_merge(data);
/* Write data: */
darray_foreach(r, *data)
for (src_offset = r->start;
src_offset < r->end;
src_offset += block_size) {
dst_offset = img.offset;
img.offset += img.block_size;
xpread(infd, buf, block_size, src_offset);
xpwrite(outfd, buf, block_size, dst_offset);
add_l2(&img, src_offset / block_size, dst_offset);
}
flush_l2(&img);
/* Write L1 table: */
dst_offset = img.offset;
img.offset += round_up(l1_size * sizeof(u64), block_size);
xpwrite(img.fd, img.l1_table, l1_size * sizeof(u64), dst_offset);
/* Write header: */
hdr.magic = cpu_to_be32(QCOW_MAGIC);
hdr.version = cpu_to_be32(QCOW_VERSION);
hdr.block_bits = cpu_to_be32(ilog2(block_size));
hdr.size = cpu_to_be64(image_size);
hdr.l1_size = cpu_to_be32(l1_size);
hdr.l1_table_offset = cpu_to_be64(dst_offset);
memset(buf, 0, block_size);
memcpy(buf, &hdr, sizeof(hdr));
xpwrite(img.fd, buf, block_size, 0);
free(img.l2_table);
free(img.l1_table);
free(buf);
}