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Add support for QCOW version 1. Version 2 is partially implemented.

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And because of that, it's entirely disabled for now. Both versions
are similar enough that a single header definition works for both
of them. The only "diverting" side-effect is that the union of the
two is larger than the official V1 header.

What this means for our V1 support is that we can't put the L1 table
adjacent to the V1 header (i.e. at offset 0x30 in the file), unless
we revert to hackery and klugery. Let's not. Instead, we align the L1
table at the cluster boundary. This is in line with the V2 layout and
perfectly ok for V1 anyway (ok -- as far as I've seen so far).
Due to the alignment, our V1 image seems to be 1 cluster larger than
the V1 image created by qemu-img (on average).

Compression of the clusters is not supported at this time.

MFC after:	2 months
This commit is contained in:
Marcel Moolenaar 2014-09-22 15:05:28 +00:00
parent fadf3fb98c
commit 38501a4664
2 changed files with 315 additions and 0 deletions
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1
usr.bin/mkimg/Makefile
View File

@ -10,6 +10,7 @@ CFLAGS+=-DSPARSE_WRITE
# List of formats to support
SRCS+= \
qcow.c \
raw.c \
vhd.c \
vmdk.c

314
usr.bin/mkimg/qcow.c Normal file
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@ -0,0 +1,314 @@
/*-
* Copyright (c) 2014 Marcel Moolenaar
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <sys/endian.h>
#include <sys/errno.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "image.h"
#include "format.h"
#include "mkimg.h"
#undef QCOW_SUPPORT_QCOW2
/* Default cluster sizes. */
#define QCOW1_CLSTR_LOG2SZ 12 /* 4KB */
#define QCOW2_CLSTR_LOG2SZ 16 /* 64KB */
struct qcow_header {
uint32_t magic;
#define QCOW_MAGIC 0x514649fb
uint32_t version;
#define QCOW_VERSION_1 1
#define QCOW_VERSION_2 2
uint64_t path_offset;
uint32_t path_length;
uint32_t clstr_log2sz; /* v2 only */
uint64_t disk_size;
union {
struct {
uint8_t clstr_log2sz;
uint8_t l2_log2sz;
uint16_t _pad;
uint32_t encryption;
uint64_t l1_offset;
} v1;
struct {
uint32_t encryption;
uint32_t l1_entries;
uint64_t l1_offset;
uint64_t refcnt_offset;
uint32_t refcnt_entries;
uint32_t snapshot_count;
uint64_t snapshot_offset;
} v2;
} u;
};
static u_int clstr_log2sz;
static uint64_t
round_clstr(uint64_t ofs)
{
uint64_t clstrsz;
clstrsz = 1UL << clstr_log2sz;
return ((ofs + clstrsz - 1) & ~(clstrsz - 1));
}
static int
qcow_resize(lba_t imgsz, u_int version)
{
uint64_t clstrsz, imagesz;
switch (version) {
case QCOW_VERSION_1:
clstr_log2sz = QCOW1_CLSTR_LOG2SZ;
break;
case QCOW_VERSION_2:
clstr_log2sz = QCOW2_CLSTR_LOG2SZ;
break;
default:
return (EDOOFUS);
}
clstrsz = 1UL << clstr_log2sz;
imagesz = round_clstr(imgsz * secsz);
if (verbose)
fprintf(stderr, "QCOW: image size = %ju, cluster size = %ju\n",
(uintmax_t)imagesz, (uintmax_t)clstrsz);
return (image_set_size(imagesz / secsz));
}
static int
qcow1_resize(lba_t imgsz)
{
return (qcow_resize(imgsz, QCOW_VERSION_1));
}
#ifdef QCOW_SUPPORT_QCOW2
static int
qcow2_resize(lba_t imgsz)
{
return (qcow_resize(imgsz, QCOW_VERSION_2));
}
#endif
static int
qcow_write(int fd, u_int version)
{
struct qcow_header *hdr;
uint64_t *l1tbl, *l2tbl;
uint16_t *rctbl;
uint64_t n, clstrsz, imagesz, nclstrs;
uint64_t l1ofs, l2ofs, ofs, rcofs;
lba_t blk, blkofs, blkcnt, imgsz;
u_int l1idx, l2idx, l2clstrs;
int error;
if (clstr_log2sz == 0)
return (EDOOFUS);
clstrsz = 1UL << clstr_log2sz;
blkcnt = clstrsz / secsz;
imgsz = image_get_size();
imagesz = imgsz * secsz;
nclstrs = imagesz >> clstr_log2sz;
l2clstrs = (nclstrs * 8 + clstrsz - 1) > clstr_log2sz;
l1ofs = clstrsz;
rcofs = round_clstr(l1ofs + l2clstrs * 8);
hdr = calloc(1, clstrsz);
if (hdr == NULL)
return (errno);
be32enc(&hdr->magic, QCOW_MAGIC);
be32enc(&hdr->version, version);
be64enc(&hdr->disk_size, imagesz);
switch (version) {
case QCOW_VERSION_1:
l2ofs = rcofs; /* No reference counting. */
hdr->u.v1.clstr_log2sz = clstr_log2sz;
hdr->u.v1.l2_log2sz = clstr_log2sz - 3;
be64enc(&hdr->u.v1.l1_offset, l1ofs);
break;
case QCOW_VERSION_2:
l2ofs = round_clstr(rcofs + (nclstrs + l2clstrs) * 2);
be32enc(&hdr->clstr_log2sz, clstr_log2sz);
be32enc(&hdr->u.v2.l1_entries, l2clstrs);
be64enc(&hdr->u.v2.l1_offset, l1ofs);
be64enc(&hdr->u.v2.refcnt_offset, rcofs);
be32enc(&hdr->u.v2.refcnt_entries, l2clstrs);
break;
default:
return (EDOOFUS);
}
l2tbl = l1tbl = NULL;
rctbl = NULL;
l1tbl = calloc(1, (size_t)(rcofs - l1ofs));
if (l1tbl == NULL) {
error = ENOMEM;
goto out;
}
if (l2ofs != rcofs) {
rctbl = calloc(1, (size_t)(l2ofs - rcofs));
if (rctbl == NULL) {
error = ENOMEM;
goto out;
}
}
ofs = l2ofs;
for (n = 0; n < nclstrs; n++) {
l1idx = n >> (clstr_log2sz - 3);
if (l1tbl[l1idx] != 0UL)
continue;
blk = n * blkcnt;
if (image_data(blk, blkcnt)) {
be64enc(l1tbl + l1idx, ofs);
ofs += clstrsz;
}
}
error = 0;
if (!error && sparse_write(fd, hdr, clstrsz) < 0)
error = errno;
if (!error && sparse_write(fd, l1tbl, (size_t)(rcofs - l1ofs)) < 0)
error = errno;
/* XXX refcnt table. */
if (error)
goto out;
free(hdr);
hdr = NULL;
if (rctbl != NULL) {
free(rctbl);
rctbl = NULL;
}
l2tbl = malloc(clstrsz);
if (l2tbl == NULL) {
error = ENOMEM;
goto out;
}
for (l1idx = 0; l1idx < l2clstrs; l1idx++) {
if (l1tbl[l1idx] == 0)
continue;
memset(l2tbl, 0, clstrsz);
blkofs = (lba_t)l1idx * (clstrsz * (clstrsz >> 3));
for (l2idx = 0; l2idx < (clstrsz >> 3); l2idx++) {
blk = blkofs + (lba_t)l2idx * blkcnt;
if (blk >= imgsz)
break;
if (image_data(blk, blkcnt)) {
be64enc(l2tbl + l2idx, ofs);
ofs += clstrsz;
}
}
if (sparse_write(fd, l2tbl, clstrsz) < 0) {
error = errno;
goto out;
}
}
free(l2tbl);
l2tbl = NULL;
free(l1tbl);
l1tbl = NULL;
error = 0;
for (n = 0; n < nclstrs; n++) {
blk = n * blkcnt;
if (image_data(blk, blkcnt)) {
error = image_copyout_region(fd, blk, blkcnt);
if (error)
break;
}
}
if (!error)
error = image_copyout_done(fd);
out:
if (l2tbl != NULL)
free(l2tbl);
if (rctbl != NULL)
free(rctbl);
if (l1tbl != NULL)
free(l1tbl);
if (hdr != NULL)
free(hdr);
return (error);
}
static int
qcow1_write(int fd)
{
return (qcow_write(fd, QCOW_VERSION_1));
}
#ifdef QCOW_SUPPORT_QCOW2
static int
qcow2_write(int fd)
{
return (qcow_write(fd, QCOW_VERSION_2));
}
#endif
static struct mkimg_format qcow1_format = {
.name = "qcow",
.description = "QEMU Copy-On-Write, version 1",
.resize = qcow1_resize,
.write = qcow1_write,
};
FORMAT_DEFINE(qcow1_format);
#ifdef QCOW_SUPPORT_QCOW2
static struct mkimg_format qcow2_format = {
.name = "qcow2",
.description = "QEMU Copy-On-Write, version 2",
.resize = qcow2_resize,
.write = qcow2_write,
};
FORMAT_DEFINE(qcow2_format);
#endif