qcrypto/core: add generic infrastructure for crypto options amendment

This will be used first to implement luks keyslot management.

block_crypto_amend_opts_init will be used to convert
qemu-img cmdline to QCryptoBlockAmendOptions

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20200608094030.670121-2-mlevitsk@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>

2 files changed, 37 insertions, 0 deletions

diff --git a/crypto/block.c b/crypto/block.c
index 6f42b32f1e..eb057948b5 100644
--- a/crypto/block.c
+++ b/crypto/block.c
@@ -150,6 +150,35 @@ qcrypto_block_calculate_payload_offset(QCryptoBlockCreateOptions *create_opts,
     return crypto != NULL;
 }
 
+int qcrypto_block_amend_options(QCryptoBlock *block,
+                                QCryptoBlockReadFunc readfunc,
+                                QCryptoBlockWriteFunc writefunc,
+                                void *opaque,
+                                QCryptoBlockAmendOptions *options,
+                                bool force,
+                                Error **errp)
+{
+    if (options->format != block->format) {
+        error_setg(errp,
+                   "Cannot amend encryption format");
+        return -1;
+    }
+
+    if (!block->driver->amend) {
+        error_setg(errp,
+                   "Crypto format %s doesn't support format options amendment",
+                   QCryptoBlockFormat_str(block->format));
+        return -1;
+    }
+
+    return block->driver->amend(block,
+                                readfunc,
+                                writefunc,
+                                opaque,
+                                options,
+                                force,
+                                errp);
+}
 
 QCryptoBlockInfo *qcrypto_block_get_info(QCryptoBlock *block,
                                          Error **errp)
diff --git a/crypto/blockpriv.h b/crypto/blockpriv.h
index 71c59cb542..3c7ccea504 100644
--- a/crypto/blockpriv.h
+++ b/crypto/blockpriv.h
@@ -62,6 +62,14 @@ struct QCryptoBlockDriver {
                   void *opaque,
                   Error **errp);
 
+    int (*amend)(QCryptoBlock *block,
+                 QCryptoBlockReadFunc readfunc,
+                 QCryptoBlockWriteFunc writefunc,
+                 void *opaque,
+                 QCryptoBlockAmendOptions *options,
+                 bool force,
+                 Error **errp);
+
     int (*get_info)(QCryptoBlock *block,
                     QCryptoBlockInfo *info,
                     Error **errp);