/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2015 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see .
***/
#include
#include "util.h"
#include "sparse-endian.h"
#include "qcow2-util.h"
#include "btrfs-util.h"
#define QCOW2_MAGIC 0x514649fb
#define QCOW2_COPIED (1ULL << 63)
#define QCOW2_COMPRESSED (1ULL << 62)
#define QCOW2_ZERO (1ULL << 0)
typedef struct _packed_ Header {
be32_t magic;
be32_t version;
be64_t backing_file_offset;
be32_t backing_file_size;
be32_t cluster_bits;
be64_t size;
be32_t crypt_method;
be32_t l1_size;
be64_t l1_table_offset;
be64_t refcount_table_offset;
be32_t refcount_table_clusters;
be32_t nb_snapshots;
be64_t snapshots_offset;
/* The remainder is only present on QCOW3 */
be64_t incompatible_features;
be64_t compatible_features;
be64_t autoclear_features;
be32_t refcount_order;
be32_t header_length;
} Header;
#define HEADER_MAGIC(header) be32toh((header)->magic)
#define HEADER_VERSION(header) be32toh((header)->version)
#define HEADER_CLUSTER_BITS(header) be32toh((header)->cluster_bits)
#define HEADER_CLUSTER_SIZE(header) (1ULL << HEADER_CLUSTER_BITS(header))
#define HEADER_L2_BITS(header) (HEADER_CLUSTER_BITS(header) - 3)
#define HEADER_SIZE(header) be64toh((header)->size)
#define HEADER_CRYPT_METHOD(header) be32toh((header)->crypt_method)
#define HEADER_L1_SIZE(header) be32toh((header)->l1_size)
#define HEADER_L2_SIZE(header) (HEADER_CLUSTER_SIZE(header)/sizeof(uint64_t))
#define HEADER_L1_TABLE_OFFSET(header) be64toh((header)->l1_table_offset)
static uint32_t HEADER_HEADER_LENGTH(const Header *h) {
if (HEADER_VERSION(h) < 3)
return offsetof(Header, incompatible_features);
return be32toh(h->header_length);
}
static int copy_cluster(
int sfd, uint64_t soffset,
int dfd, uint64_t doffset,
uint64_t cluster_size,
void *buffer) {
ssize_t l;
int r;
r = btrfs_clone_range(sfd, soffset, dfd, doffset, cluster_size);
if (r >= 0)
return r;
l = pread(sfd, buffer, cluster_size, soffset);
if (l < 0)
return -errno;
if ((uint64_t) l != cluster_size)
return -EIO;
l = pwrite(dfd, buffer, cluster_size, doffset);
if (l < 0)
return -errno;
if ((uint64_t) l != cluster_size)
return -EIO;
return 0;
}
static int decompress_cluster(
int sfd, uint64_t soffset,
int dfd, uint64_t doffset,
uint64_t compressed_size,
uint64_t cluster_size,
void *buffer1,
void *buffer2) {
_cleanup_free_ void *large_buffer = NULL;
z_stream s = {};
uint64_t sz;
ssize_t l;
int r;
if (compressed_size > cluster_size) {
/* The usual cluster buffer doesn't suffice, let's
* allocate a larger one, temporarily */
large_buffer = malloc(compressed_size);
if (!large_buffer)
return -ENOMEM;
buffer1 = large_buffer;
}
l = pread(sfd, buffer1, compressed_size, soffset);
if (l < 0)
return -errno;
if ((uint64_t) l != compressed_size)
return -EIO;
s.next_in = buffer1;
s.avail_in = compressed_size;
s.next_out = buffer2;
s.avail_out = cluster_size;
r = inflateInit2(&s, -12);
if (r != Z_OK)
return -EIO;
r = inflate(&s, Z_FINISH);
sz = (uint8_t*) s.next_out - (uint8_t*) buffer2;
inflateEnd(&s);
if (r != Z_STREAM_END || sz != cluster_size)
return -EIO;
l = pwrite(dfd, buffer2, cluster_size, doffset);
if (l < 0)
return -errno;
if ((uint64_t) l != cluster_size)
return -EIO;
return 0;
}
static int normalize_offset(
const Header *header,
uint64_t p,
uint64_t *ret,
bool *compressed,
uint64_t *compressed_size) {
uint64_t q;
q = be64toh(p);
if (q & QCOW2_COMPRESSED) {
uint64_t sz, csize_shift, csize_mask;
if (!compressed)
return -ENOTSUP;
csize_shift = 64 - 2 - (HEADER_CLUSTER_BITS(header) - 8);
csize_mask = (1ULL << (HEADER_CLUSTER_BITS(header) - 8)) - 1;
sz = (((q >> csize_shift) & csize_mask) + 1) * 512 - (q & 511);
q &= ((1ULL << csize_shift) - 1);
if (compressed_size)
*compressed_size = sz;
*compressed = true;
} else {
if (compressed) {
*compressed = false;
*compressed_size = 0;
}
if (q & QCOW2_ZERO) {
/* We make no distinction between zero blocks and holes */
*ret = 0;
return 0;
}
q &= ~QCOW2_COPIED;
}
*ret = q;
return q > 0; /* returns positive if not a hole */
}
static int verify_header(const Header *header) {
assert(header);
if (HEADER_MAGIC(header) != QCOW2_MAGIC)
return -EBADMSG;
if (HEADER_VERSION(header) != 2 &&
HEADER_VERSION(header) != 3)
return -ENOTSUP;
if (HEADER_CRYPT_METHOD(header) != 0)
return -ENOTSUP;
if (HEADER_CLUSTER_BITS(header) < 9) /* 512K */
return -EBADMSG;
if (HEADER_CLUSTER_BITS(header) > 21) /* 2MB */
return -EBADMSG;
if (HEADER_SIZE(header) % HEADER_CLUSTER_SIZE(header) != 0)
return -EBADMSG;
if (HEADER_L1_SIZE(header) > 32*1024*1024) /* 32MB */
return -EBADMSG;
if (HEADER_VERSION(header) == 3) {
if (header->incompatible_features != 0)
return -ENOTSUP;
if (HEADER_HEADER_LENGTH(header) < sizeof(Header))
return -EBADMSG;
}
return 0;
}
int qcow2_convert(int qcow2_fd, int raw_fd) {
_cleanup_free_ void *buffer1 = NULL, *buffer2 = NULL;
_cleanup_free_ be64_t *l1_table = NULL, *l2_table = NULL;
uint64_t sz, i;
Header header;
ssize_t l;
int r;
l = pread(qcow2_fd, &header, sizeof(header), 0);
if (l < 0)
return -errno;
if (l != sizeof(header))
return -EIO;
r = verify_header(&header);
if (r < 0)
return r;
l1_table = new(be64_t, HEADER_L1_SIZE(&header));
if (!l1_table)
return -ENOMEM;
l2_table = malloc(HEADER_CLUSTER_SIZE(&header));
if (!l2_table)
return -ENOMEM;
buffer1 = malloc(HEADER_CLUSTER_SIZE(&header));
if (!buffer1)
return -ENOMEM;
buffer2 = malloc(HEADER_CLUSTER_SIZE(&header));
if (!buffer2)
return -ENOMEM;
/* Empty the file if it exists, we rely on zero bits */
if (ftruncate(raw_fd, 0) < 0)
return -errno;
if (ftruncate(raw_fd, HEADER_SIZE(&header)) < 0)
return -errno;
sz = sizeof(uint64_t) * HEADER_L1_SIZE(&header);
l = pread(qcow2_fd, l1_table, sz, HEADER_L1_TABLE_OFFSET(&header));
if (l < 0)
return -errno;
if ((uint64_t) l != sz)
return -EIO;
for (i = 0; i < HEADER_L1_SIZE(&header); i ++) {
uint64_t l2_begin, j;
r = normalize_offset(&header, l1_table[i], &l2_begin, NULL, NULL);
if (r < 0)
return r;
if (r == 0)
continue;
l = pread(qcow2_fd, l2_table, HEADER_CLUSTER_SIZE(&header), l2_begin);
if (l < 0)
return -errno;
if ((uint64_t) l != HEADER_CLUSTER_SIZE(&header))
return -EIO;
for (j = 0; j < HEADER_L2_SIZE(&header); j++) {
uint64_t data_begin, p, compressed_size;
bool compressed;
p = ((i << HEADER_L2_BITS(&header)) + j) << HEADER_CLUSTER_BITS(&header);
r = normalize_offset(&header, l2_table[j], &data_begin, &compressed, &compressed_size);
if (r < 0)
return r;
if (r == 0)
continue;
if (compressed)
r = decompress_cluster(
qcow2_fd, data_begin,
raw_fd, p,
compressed_size, HEADER_CLUSTER_SIZE(&header),
buffer1, buffer2);
else
r = copy_cluster(
qcow2_fd, data_begin,
raw_fd, p,
HEADER_CLUSTER_SIZE(&header), buffer1);
if (r < 0)
return r;
}
}
return 0;
}
int qcow2_detect(int fd) {
be32_t id;
ssize_t l;
l = pread(fd, &id, sizeof(id), 0);
if (l < 0)
return -errno;
if (l != sizeof(id))
return -EIO;
return htobe32(QCOW2_MAGIC) == id;
}