crypto/hash-glib: Implement new hash API

Implements the new hashing API in the GLib hash driver.
Supports creating/destroying a context, updating the context
with input data and obtaining an output hash.

Signed-off-by: Alejandro Zeise <alejandro.zeise@seagate.com>
[ clg: - Dropped qcrypto_hash_supports() in qcrypto_glib_hash_new()
       - Removed superfluous cast (GChecksum *) in qcrypto_glib_hash_free()
       - Reworked qcrypto_glib_hash_finalize() ]
Signed-off-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

crypto/hash-glib.c

@@ -1,6 +1,7 @@
 /*
  * QEMU Crypto hash algorithms
  *
+ * Copyright (c) 2024 Seagate Technology LLC and/or its Affiliates
  * Copyright (c) 2016 Red Hat, Inc.
  *
  * This library is free software; you can redistribute it and/or
@@ -95,6 +96,72 @@ qcrypto_glib_hash_bytesv(QCryptoHashAlgo alg,
 }
 
 
+static
+QCryptoHash *qcrypto_glib_hash_new(QCryptoHashAlgo alg,
+                                   Error **errp)
+{
+    QCryptoHash *hash;
+
+    hash = g_new(QCryptoHash, 1);
+    hash->alg = alg;
+    hash->opaque = g_checksum_new(qcrypto_hash_alg_map[alg]);
+
+    return hash;
+}
+
+static
+void qcrypto_glib_hash_free(QCryptoHash *hash)
+{
+    if (hash->opaque) {
+        g_checksum_free(hash->opaque);
+    }
+
+    g_free(hash);
+}
+
+
+static
+int qcrypto_glib_hash_update(QCryptoHash *hash,
+                             const struct iovec *iov,
+                             size_t niov,
+                             Error **errp)
+{
+    GChecksum *ctx = hash->opaque;
+
+    for (int i = 0; i < niov; i++) {
+        g_checksum_update(ctx, iov[i].iov_base, iov[i].iov_len);
+    }
+
+    return 0;
+}
+
+static
+int qcrypto_glib_hash_finalize(QCryptoHash *hash,
+                               uint8_t **result,
+                               size_t *result_len,
+                               Error **errp)
+{
+    int ret;
+    GChecksum *ctx = hash->opaque;
+
+    ret = g_checksum_type_get_length(qcrypto_hash_alg_map[hash->alg]);
+    if (ret < 0) {
+        error_setg(errp, "Unable to get hash length");
+        *result_len = 0;
+        return -1;
+    }
+
+    *result_len = ret;
+    *result = g_new(uint8_t, *result_len);
+
+    g_checksum_get_digest(ctx, *result, result_len);
+    return 0;
+}
+
 QCryptoHashDriver qcrypto_hash_lib_driver = {
     .hash_bytesv = qcrypto_glib_hash_bytesv,
+    .hash_new      = qcrypto_glib_hash_new,
+    .hash_update   = qcrypto_glib_hash_update,
+    .hash_finalize = qcrypto_glib_hash_finalize,
+    .hash_free     = qcrypto_glib_hash_free,
 };