From patchwork Wed Sep 6 11:15:47 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Albert Esteve X-Patchwork-Id: 13375544 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 75933EB8FB7 for ; Wed, 6 Sep 2023 11:17:27 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qdqVu-0001IJ-Jf; Wed, 06 Sep 2023 07:16:02 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qdqVt-0001GV-Kb for qemu-devel@nongnu.org; Wed, 06 Sep 2023 07:16:01 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qdqVq-0005Mu-VI for qemu-devel@nongnu.org; Wed, 06 Sep 2023 07:16:01 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1693998957; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=p5K4SJpmOiLjmLRGTSdh0oibRI8/KmAFLLAbdAWOlzc=; b=BZwlpCe58cRijJB2YubCBi1bTHx4valitY5ASm8gC/uhX8F/alx8XUEKV312qbT6cIVVW2 RjZIqbYHQADqPCnnUThnCFSFehloI7lHRUDv/UJPoaV9MKPtL5MoR1e7ftq0ueir6GDHqo rDLaqvV7Igyl9chzm4GYxNM675tKcfE= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-696-Go9Xte5lNPC30xpcrbnO9A-1; Wed, 06 Sep 2023 07:15:54 -0400 X-MC-Unique: Go9Xte5lNPC30xpcrbnO9A-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 009611C03D80; Wed, 6 Sep 2023 11:15:54 +0000 (UTC) Received: from fedora.redhat.com (unknown [10.45.225.49]) by smtp.corp.redhat.com (Postfix) with ESMTP id 6C5E421EE565; Wed, 6 Sep 2023 11:15:52 +0000 (UTC) From: Albert Esteve To: qemu-devel@nongnu.org Cc: philmd@linaro.org, Fam Zheng , "Michael S. Tsirkin" , cohuck@redhat.com, Albert Esteve , kraxel@redhat.com, marcandre.lureau@gmail.com Subject: [PATCH v6 1/3] uuid: add a hash function Date: Wed, 6 Sep 2023 13:15:47 +0200 Message-ID: <20230906111549.357178-2-aesteve@redhat.com> In-Reply-To: <20230906111549.357178-1-aesteve@redhat.com> References: <20230906111549.357178-1-aesteve@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.6 Received-SPF: pass client-ip=170.10.133.124; envelope-from=aesteve@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Add hash function to uuid module using the djb2 hash algorithm. Add a couple simple unit tests for the hash function, checking collisions for similar UUIDs. Reviewed-by: Philippe Mathieu-Daudé Signed-off-by: Albert Esteve --- include/qemu/uuid.h | 2 ++ tests/unit/test-uuid.c | 27 +++++++++++++++++++++++++++ util/uuid.c | 15 +++++++++++++++ 3 files changed, 44 insertions(+) diff --git a/include/qemu/uuid.h b/include/qemu/uuid.h index dc40ee1fc9..e24a1099e4 100644 --- a/include/qemu/uuid.h +++ b/include/qemu/uuid.h @@ -96,4 +96,6 @@ int qemu_uuid_parse(const char *str, QemuUUID *uuid); QemuUUID qemu_uuid_bswap(QemuUUID uuid); +uint32_t qemu_uuid_hash(const void *uuid); + #endif diff --git a/tests/unit/test-uuid.c b/tests/unit/test-uuid.c index c111de5fc1..aedc125ae9 100644 --- a/tests/unit/test-uuid.c +++ b/tests/unit/test-uuid.c @@ -171,6 +171,32 @@ static void test_uuid_unparse_strdup(void) } } +static void test_uuid_hash(void) +{ + QemuUUID uuid; + int i; + + for (i = 0; i < 100; i++) { + qemu_uuid_generate(&uuid); + /* Obtain the UUID hash */ + uint32_t hash_a = qemu_uuid_hash(&uuid); + int data_idx = g_random_int_range(0, 15); + /* Change a single random byte of the UUID */ + if (uuid.data[data_idx] < 0xFF) { + uuid.data[data_idx]++; + } else { + uuid.data[data_idx]--; + } + /* Obtain the UUID hash again */ + uint32_t hash_b = qemu_uuid_hash(&uuid); + /* + * Both hashes shall be different (avoid collision) + * for any change in the UUID fields + */ + g_assert_cmpint(hash_a, !=, hash_b); + } +} + int main(int argc, char **argv) { g_test_init(&argc, &argv, NULL); @@ -179,6 +205,7 @@ int main(int argc, char **argv) g_test_add_func("/uuid/parse", test_uuid_parse); g_test_add_func("/uuid/unparse", test_uuid_unparse); g_test_add_func("/uuid/unparse_strdup", test_uuid_unparse_strdup); + g_test_add_func("/uuid/hash", test_uuid_hash); return g_test_run(); } diff --git a/util/uuid.c b/util/uuid.c index b1108dde78..b366961bc6 100644 --- a/util/uuid.c +++ b/util/uuid.c @@ -116,3 +116,18 @@ QemuUUID qemu_uuid_bswap(QemuUUID uuid) bswap16s(&uuid.fields.time_high_and_version); return uuid; } + +/* djb2 hash algorithm */ +uint32_t qemu_uuid_hash(const void *uuid) +{ + QemuUUID *qid = (QemuUUID *) uuid; + uint32_t h = 5381; + int i; + + for (i = 0; i < ARRAY_SIZE(qid->data); i++) { + h = (h << 5) + h + qid->data[i]; + } + + return h; +} +