From nobody Sun Feb 8 14:31:10 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of redhat.com designates 209.132.183.28 as permitted sender) client-ip=209.132.183.28; envelope-from=libvir-list-bounces@redhat.com; helo=mx1.redhat.com; Authentication-Results: mx.zoho.com; spf=pass (zoho.com: domain of redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=libvir-list-bounces@redhat.com; Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by mx.zohomail.com with SMTPS id 1492682664346888.6079724447345; Thu, 20 Apr 2017 03:04:24 -0700 (PDT) Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 10F2965403; Thu, 20 Apr 2017 10:04:22 +0000 (UTC) Received: from colo-mx.corp.redhat.com (colo-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.20]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D584780B0A; Thu, 20 Apr 2017 10:04:21 +0000 (UTC) Received: from lists01.pubmisc.prod.ext.phx2.redhat.com (lists01.pubmisc.prod.ext.phx2.redhat.com [10.5.19.33]) by colo-mx.corp.redhat.com (Postfix) with ESMTP id 7D4EB18523D2; Thu, 20 Apr 2017 10:04:04 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) by lists01.pubmisc.prod.ext.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id v3KA2O3C001373 for ; Thu, 20 Apr 2017 06:02:24 -0400 Received: by smtp.corp.redhat.com (Postfix) id 1F8457F6C1; Thu, 20 Apr 2017 10:02:24 +0000 (UTC) Received: from moe.brq.redhat.com (dhcp129-131.brq.redhat.com [10.34.129.131]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9B7A37F6C8 for ; Thu, 20 Apr 2017 10:02:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 10F2965403 Authentication-Results: ext-mx10.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx10.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=libvir-list-bounces@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 10F2965403 From: Michal Privoznik To: libvir-list@redhat.com Date: Thu, 20 Apr 2017 12:01:40 +0200 Message-Id: <91c17c14a5355c0221ff24e34727550673847bae.1492682033.git.mprivozn@redhat.com> In-Reply-To: References: In-Reply-To: References: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-loop: libvir-list@redhat.com Subject: [libvirt] [PATCH v2 11/38] Introduce virStreamSkip X-BeenThere: libvir-list@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: Development discussions about the libvirt library & tools List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Sender: libvir-list-bounces@redhat.com Errors-To: libvir-list-bounces@redhat.com X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Thu, 20 Apr 2017 10:04:22 +0000 (UTC) X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Type: text/plain; charset="utf-8" This API can be used to tell the other side of the stream to skip some bytes in the stream. This can be used to create a sparse file on the receiving side of a stream. It takes just one argument @length, which says how big the hole is. Since our streams are not rewindable like regular files, we don't need @whence argument like seek(2) has. Signed-off-by: Michal Privoznik --- include/libvirt/libvirt-stream.h | 3 +++ src/driver-stream.h | 5 ++++ src/libvirt-stream.c | 57 ++++++++++++++++++++++++++++++++++++= ++++ src/libvirt_public.syms | 1 + 4 files changed, 66 insertions(+) diff --git a/include/libvirt/libvirt-stream.h b/include/libvirt/libvirt-str= eam.h index bee2516..4e0a599 100644 --- a/include/libvirt/libvirt-stream.h +++ b/include/libvirt/libvirt-stream.h @@ -50,6 +50,9 @@ int virStreamRecvFlags(virStreamPtr st, size_t nbytes, unsigned int flags); =20 +int virStreamSkip(virStreamPtr st, + unsigned long long length); + =20 /** * virStreamSourceFunc: diff --git a/src/driver-stream.h b/src/driver-stream.h index d4b0480..20ea13f 100644 --- a/src/driver-stream.h +++ b/src/driver-stream.h @@ -42,6 +42,10 @@ typedef int unsigned int flags); =20 typedef int +(*virDrvStreamSkip)(virStreamPtr st, + unsigned long long length); + +typedef int (*virDrvStreamEventAddCallback)(virStreamPtr stream, int events, virStreamEventCallback cb, @@ -68,6 +72,7 @@ struct _virStreamDriver { virDrvStreamSend streamSend; virDrvStreamRecv streamRecv; virDrvStreamRecvFlags streamRecvFlags; + virDrvStreamSkip streamSkip; virDrvStreamEventAddCallback streamEventAddCallback; virDrvStreamEventUpdateCallback streamEventUpdateCallback; virDrvStreamEventRemoveCallback streamEventRemoveCallback; diff --git a/src/libvirt-stream.c b/src/libvirt-stream.c index 80b2d47..55f3ef5 100644 --- a/src/libvirt-stream.c +++ b/src/libvirt-stream.c @@ -346,6 +346,63 @@ virStreamRecvFlags(virStreamPtr stream, =20 =20 /** + * virStreamSkip: + * @stream: pointer to the stream object + * @length: number of bytes to skip + * + * Skip @length bytes in the stream. This is useful when there's + * no actual data in the stream, just a hole. If that's the case, + * this API can be used to skip the hole properly instead of + * transmitting zeroes to the other side. + * + * An example using this with a hypothetical file upload API + * looks like: + * + * virStream st; + * + * while (1) { + * char buf[4096]; + * size_t len; + * if (..in hole...) { + * ..get hole size... + * virStreamSkip(st, len); + * } else { + * ...read len bytes... + * virStreamSend(st, buf, len); + * } + * } + * + * Returns 0 on success, + * -1 error + */ +int +virStreamSkip(virStreamPtr stream, + unsigned long long length) +{ + VIR_DEBUG("stream=3D%p, length=3D%llu", stream, length); + + virResetLastError(); + + virCheckStreamReturn(stream, -1); + + if (stream->driver && + stream->driver->streamSkip) { + int ret; + ret =3D (stream->driver->streamSkip)(stream, length); + if (ret < 0) + goto error; + return ret; + } + + virReportUnsupportedError(); + + error: + virDispatchError(stream->conn); + return -1; +} + + +/** * virStreamSendAll: * @stream: pointer to the stream object * @handler: source callback for reading data from application diff --git a/src/libvirt_public.syms b/src/libvirt_public.syms index af863bb..acadda8 100644 --- a/src/libvirt_public.syms +++ b/src/libvirt_public.syms @@ -762,6 +762,7 @@ LIBVIRT_3.1.0 { LIBVIRT_3.3.0 { global: virStreamRecvFlags; + virStreamSkip; } LIBVIRT_3.1.0; =20 # .... define new API here using predicted next version number .... --=20 2.10.2 -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list