luks: extract qcrypto_block_calculate_payload_offset()
The qcow2 .bdrv_measure() code calculates the crypto payload offset.
This logic really belongs in crypto/block.c where it can be reused by
other image formats.
The "luks" block driver will need this same logic in order to implement
.bdrv_measure(), so extract the qcrypto_block_calculate_payload_offset()
function now.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200221112522.1497712-2-stefanha@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
diff --git a/block/qcow2.c b/block/qcow2.c
index 3640e8c..f667349 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -4608,60 +4608,6 @@
return ret;
}
-static ssize_t qcow2_measure_crypto_hdr_init_func(QCryptoBlock *block,
- size_t headerlen, void *opaque, Error **errp)
-{
- size_t *headerlenp = opaque;
-
- /* Stash away the payload size */
- *headerlenp = headerlen;
- return 0;
-}
-
-static ssize_t qcow2_measure_crypto_hdr_write_func(QCryptoBlock *block,
- size_t offset, const uint8_t *buf, size_t buflen,
- void *opaque, Error **errp)
-{
- /* Discard the bytes, we're not actually writing to an image */
- return buflen;
-}
-
-/* Determine the number of bytes for the LUKS payload */
-static bool qcow2_measure_luks_headerlen(QemuOpts *opts, size_t *len,
- Error **errp)
-{
- QDict *opts_qdict;
- QDict *cryptoopts_qdict;
- QCryptoBlockCreateOptions *cryptoopts;
- QCryptoBlock *crypto;
-
- /* Extract "encrypt." options into a qdict */
- opts_qdict = qemu_opts_to_qdict(opts, NULL);
- qdict_extract_subqdict(opts_qdict, &cryptoopts_qdict, "encrypt.");
- qobject_unref(opts_qdict);
-
- /* Build QCryptoBlockCreateOptions object from qdict */
- qdict_put_str(cryptoopts_qdict, "format", "luks");
- cryptoopts = block_crypto_create_opts_init(cryptoopts_qdict, errp);
- qobject_unref(cryptoopts_qdict);
- if (!cryptoopts) {
- return false;
- }
-
- /* Fake LUKS creation in order to determine the payload size */
- crypto = qcrypto_block_create(cryptoopts, "encrypt.",
- qcow2_measure_crypto_hdr_init_func,
- qcow2_measure_crypto_hdr_write_func,
- len, errp);
- qapi_free_QCryptoBlockCreateOptions(cryptoopts);
- if (!crypto) {
- return false;
- }
-
- qcrypto_block_free(crypto);
- return true;
-}
-
static BlockMeasureInfo *qcow2_measure(QemuOpts *opts, BlockDriverState *in_bs,
Error **errp)
{
@@ -4712,9 +4658,27 @@
g_free(optstr);
if (has_luks) {
+ g_autoptr(QCryptoBlockCreateOptions) create_opts = NULL;
+ QDict *opts_qdict;
+ QDict *cryptoopts;
size_t headerlen;
- if (!qcow2_measure_luks_headerlen(opts, &headerlen, &local_err)) {
+ opts_qdict = qemu_opts_to_qdict(opts, NULL);
+ qdict_extract_subqdict(opts_qdict, &cryptoopts, "encrypt.");
+ qobject_unref(opts_qdict);
+
+ qdict_put_str(cryptoopts, "format", "luks");
+
+ create_opts = block_crypto_create_opts_init(cryptoopts, errp);
+ qobject_unref(cryptoopts);
+ if (!create_opts) {
+ goto err;
+ }
+
+ if (!qcrypto_block_calculate_payload_offset(create_opts,
+ "encrypt.",
+ &headerlen,
+ &local_err)) {
goto err;
}
