--- /dev/null
+/*-*- 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 <http://www.gnu.org/licenses/>.
+***/
+
+#include <zlib.h>
+
+#include "util.h"
+#include "sparse-endian.h"
+#include "qcow2-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;
+
+ 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;
+}
projects / thirdparty / systemd.git / commitdiff
