From nobody Mon Feb 9 14:33:37 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zohomail.com: domain of redhat.com designates 170.10.133.124 as permitted sender) client-ip=170.10.133.124; envelope-from=libvir-list-bounces@redhat.com; helo=us-smtp-delivery-124.mimecast.com; Authentication-Results: mx.zohomail.com; spf=pass (zohomail.com: domain of redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=libvir-list-bounces@redhat.com; dmarc=fail(p=none dis=none) header.from=suse.de Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by mx.zohomail.com with SMTPS id 1652543632796710.6641761976126; Sat, 14 May 2022 08:53:52 -0700 (PDT) Received: from mimecast-mx02.redhat.com (mx3-rdu2.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-326-8Vnq6uWJOAScYBEEYx_zkg-1; Sat, 14 May 2022 11:53:46 -0400 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id E8A701C0F6B2; Sat, 14 May 2022 15:53:35 +0000 (UTC) Received: from mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (unknown [10.30.29.100]) by smtp.corp.redhat.com (Postfix) with ESMTP id 72D27416537; Sat, 14 May 2022 15:53:34 +0000 (UTC) Received: from mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (localhost [IPv6:::1]) by mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (Postfix) with ESMTP id A45C5192B835; Sat, 14 May 2022 15:53:28 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) by mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (Postfix) with ESMTP id 50A68196A5C2 for ; Sat, 14 May 2022 15:53:25 +0000 (UTC) Received: by smtp.corp.redhat.com (Postfix) id 1BF8F9D42; Sat, 14 May 2022 15:53:25 +0000 (UTC) Received: from mimecast-mx02.redhat.com (mimecast03.extmail.prod.ext.rdu2.redhat.com [10.11.55.19]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 16CCD815B for ; Sat, 14 May 2022 15:53:20 +0000 (UTC) Received: from us-smtp-1.mimecast.com (us-smtp-1.mimecast.com [205.139.110.61]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 93B17811E75 for ; Sat, 14 May 2022 15:53:20 +0000 (UTC) Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-18-mSKeDAfyOdCI2AcwcJM5Yw-1; Sat, 14 May 2022 11:53:18 -0400 Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 41EF221D53; Sat, 14 May 2022 15:53:17 +0000 (UTC) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 0C7DE13ADC; Sat, 14 May 2022 15:53:17 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id wL1nAW3Qf2J2ZwAAMHmgww (envelope-from ); Sat, 14 May 2022 15:53:17 +0000 X-MC-Unique: 8Vnq6uWJOAScYBEEYx_zkg-1 X-Original-To: libvir-list@listman.corp.redhat.com X-MC-Unique: mSKeDAfyOdCI2AcwcJM5Yw-1 From: Claudio Fontana To: =?UTF-8?q?Daniel=20P=20=2E=20Berrang=C3=A9?= Subject: [libvirt RFCv9 03/31] qemu: saveimage: rework save format and read/write to be O_DIRECT friendly Date: Sat, 14 May 2022 17:52:45 +0200 Message-Id: <20220514155313.9615-4-cfontana@suse.de> In-Reply-To: <20220514155313.9615-1-cfontana@suse.de> References: <20220514155313.9615-1-cfontana@suse.de> MIME-Version: 1.0 X-Mimecast-Impersonation-Protect: Policy=CLT - Impersonation Protection Definition; Similar Internal Domain=false; Similar Monitored External Domain=false; Custom External Domain=false; Mimecast External Domain=false; Newly Observed Domain=false; Internal User Name=false; Custom Display Name List=false; Reply-to Address Mismatch=false; Targeted Threat Dictionary=false; Mimecast Threat Dictionary=false; Custom Threat Dictionary=false X-Scanned-By: MIMEDefang 2.79 on 10.11.54.5 X-BeenThere: libvir-list@redhat.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: Development discussions about the libvirt library & tools List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: libvir-list@redhat.com, "Dr . David Alan Gilbert" , Claudio Fontana Errors-To: libvir-list-bounces@redhat.com Sender: "libvir-list" X-Scanned-By: MIMEDefang 2.85 on 10.11.54.9 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=libvir-list-bounces@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable X-ZM-MESSAGEID: 1652543634588100005 Content-Type: text/plain; charset="utf-8"; x-default="true" change the saveimage format to: 1) ensure that the header struct fields are packed, so we can be sure no padding will ruin the day 2) finish the libvirt header (header + xml + cookie) with zero padding, in order to ensure that the QEMU VM (QEVM Magic) is aligned. Adapt the read and write of the libvirt header accordingly. Signed-off-by: Claudio Fontana --- src/qemu/qemu_saveimage.c | 229 ++++++++++++++++++++++---------------- src/qemu/qemu_saveimage.h | 22 ++-- 2 files changed, 143 insertions(+), 108 deletions(-) diff --git a/src/qemu/qemu_saveimage.c b/src/qemu/qemu_saveimage.c index 4fd4c5cfcd..7db54f11e1 100644 --- a/src/qemu/qemu_saveimage.c +++ b/src/qemu/qemu_saveimage.c @@ -139,12 +139,12 @@ virQEMUSaveDataWrite(virQEMUSaveData *data, int fd, const char *path) { + g_autofree void *base =3D NULL; + char *buf, *cur; virQEMUSaveHeader *header =3D &data->header; size_t len; size_t xml_len; size_t cookie_len =3D 0; - size_t zerosLen =3D 0; - g_autofree char *zeros =3D NULL; =20 xml_len =3D strlen(data->xml) + 1; if (data->cookie) @@ -165,42 +165,148 @@ virQEMUSaveDataWrite(virQEMUSaveData *data, return -1; } } - - zerosLen =3D header->data_len - len; - zeros =3D g_new0(char, zerosLen); + buf =3D virFileDirectBufferNew(&base, sizeof(*header) + header->data_l= en); + cur =3D buf; =20 if (data->cookie) header->cookieOffset =3D xml_len; =20 - if (safewrite(fd, header, sizeof(*header)) !=3D sizeof(*header)) { - virReportSystemError(errno, - _("failed to write header to domain save file= '%s'"), - path); - return -1; + memcpy(cur, header, sizeof(*header)); + cur +=3D sizeof(*header); + memcpy(cur, data->xml, xml_len); + cur +=3D xml_len; + if (data->cookie) { + memcpy(cur, data->cookie, cookie_len); + cur +=3D cookie_len; } =20 - if (safewrite(fd, data->xml, xml_len) !=3D xml_len) { + if (virFileDirectWrite(fd, buf, sizeof(*header) + header->data_len) < = 0) { virReportSystemError(errno, - _("failed to write domain xml to '%s'"), + _("failed to write libvirt header of domain s= ave file '%s'"), path); return -1; } =20 - if (data->cookie && - safewrite(fd, data->cookie, cookie_len) !=3D cookie_len) { + return 0; +} + +/* virQEMUSaveDataRead: + * + * Reads libvirt's header (including domain XML) from a saved image. + * + * Returns -1 on generic failure, -3 on a corrupted image, or 0 on success. + */ +int +virQEMUSaveDataRead(virQEMUSaveData *data, + int fd, + const char *path) +{ + g_autofree void *base =3D NULL; + virQEMUSaveHeader *header =3D &data->header; + size_t xml_len; + size_t cookie_len; + ssize_t rv; + size_t buflen =3D 1024 * 1024; + void *dst; + char *buf =3D virFileDirectBufferNew(&base, buflen); + void *src =3D buf; + + header =3D &data->header; + rv =3D virFileDirectReadCopy(fd, &src, buflen, header, sizeof(*header)= ); + if (rv < 0) { virReportSystemError(errno, - _("failed to write cookie to '%s'"), + _("failed to read libvirt header of domain sa= ve file '%s'"), path); return -1; } + if (rv < sizeof(*header)) { + virReportError(VIR_ERR_OPERATION_FAILED, + _("domain save file '%s' libvirt header appears tru= ncated"), + path); + return -3; + } + rv -=3D sizeof(*header); =20 - if (safewrite(fd, zeros, zerosLen) !=3D zerosLen) { - virReportSystemError(errno, - _("failed to write padding to '%s'"), - path); + if (memcmp(header->magic, QEMU_SAVE_MAGIC, sizeof(header->magic)) !=3D= 0) { + if (memcmp(header->magic, QEMU_SAVE_PARTIAL, sizeof(header->magic)= ) =3D=3D 0) { + virReportError(VIR_ERR_OPERATION_FAILED, + _("domain save file '%s' seems incomplete"), + path); + return -3; + } + virReportError(VIR_ERR_OPERATION_FAILED, "%s", + _("image magic is incorrect")); + return -1; + } + if (header->version > QEMU_SAVE_VERSION) { + /* convert endianness and try again */ + qemuSaveImageBswapHeader(header); + } + if (header->version > QEMU_SAVE_VERSION) { + virReportError(VIR_ERR_OPERATION_FAILED, + _("image version is not supported (%d > %d)"), + header->version, QEMU_SAVE_VERSION); return -1; } + if (header->cookieOffset) + xml_len =3D header->cookieOffset; + else + xml_len =3D header->data_len; =20 + if (xml_len <=3D 0) { + virReportError(VIR_ERR_OPERATION_FAILED, + _("invalid xml length: %lu"), xml_len); + return -1; + } + if (header->data_len < xml_len) { + virReportError(VIR_ERR_OPERATION_FAILED, + _("invalid cookieOffset: %u"), header->cookieOffset= ); + return -1; + } + cookie_len =3D header->data_len - xml_len; + data->xml =3D g_new0(char, xml_len); + dst =3D data->xml; + if (rv > 0) { + rv -=3D virFileDirectCopyBuf(&src, rv, &dst, &xml_len); + } + if (xml_len > 0) { + rv =3D virFileDirectReadCopy(fd, &src, buflen, dst, xml_len); + if (rv < 0) { + virReportSystemError(errno, + _("failed to read libvirt xml in domain s= ave file '%s'"), + path); + return -1; + } + if (rv < xml_len) { + virReportError(VIR_ERR_OPERATION_FAILED, + _("domain save file '%s' xml seems incomplete"), + path); + return -3; + } + } + if (cookie_len > 0) { + data->cookie =3D g_new0(char, cookie_len); + dst =3D data->cookie; + if (rv > 0) { + rv -=3D virFileDirectCopyBuf(&src, rv, &dst, &cookie_len); + } + if (cookie_len > 0) { + rv =3D virFileDirectReadCopy(fd, &src, buflen, dst, cookie_len= ); + if (rv < 0) { + virReportSystemError(errno, + _("failed to read libvirt cookie in d= omain save file '%s'"), + path); + return -1; + } + if (rv < cookie_len) { + virReportError(VIR_ERR_OPERATION_FAILED, + _("domain save file '%s' cookie seems incom= plete"), + path); + return -3; + } + } + } + /* we should now be aligned and ready to read the QEVM */ return 0; } =20 @@ -444,11 +550,8 @@ qemuSaveImageOpen(virQEMUDriver *driver, VIR_AUTOCLOSE fd =3D -1; int ret =3D -1; g_autoptr(virQEMUSaveData) data =3D NULL; - virQEMUSaveHeader *header; g_autoptr(virDomainDef) def =3D NULL; int oflags =3D open_write ? O_RDWR : O_RDONLY; - size_t xml_len; - size_t cookie_len; =20 if (bypass_cache) { int directFlag =3D virFileDirectFdFlag(); @@ -469,89 +572,17 @@ qemuSaveImageOpen(virQEMUDriver *driver, return -1; =20 data =3D g_new0(virQEMUSaveData, 1); - - header =3D &data->header; - if (saferead(fd, header, sizeof(*header)) !=3D sizeof(*header)) { - if (unlink_corrupt) { + ret =3D virQEMUSaveDataRead(data, fd, path); + if (ret < 0) { + if (unlink_corrupt && ret =3D=3D -3) { if (unlink(path) < 0) { virReportSystemError(errno, _("cannot remove corrupt file: %s"), path); return -1; - } else { - return -3; - } - } - - virReportError(VIR_ERR_OPERATION_FAILED, - "%s", _("failed to read qemu header")); - return -1; - } - - if (memcmp(header->magic, QEMU_SAVE_MAGIC, sizeof(header->magic)) !=3D= 0) { - if (memcmp(header->magic, QEMU_SAVE_PARTIAL, sizeof(header->magic)= ) =3D=3D 0) { - if (unlink_corrupt) { - if (unlink(path) < 0) { - virReportSystemError(errno, - _("cannot remove corrupt file: %s= "), - path); - return -1; - } else { - return -3; - } } - - virReportError(VIR_ERR_OPERATION_FAILED, "%s", - _("save image is incomplete")); - return -1; - } - - virReportError(VIR_ERR_OPERATION_FAILED, "%s", - _("image magic is incorrect")); - return -1; - } - - if (header->version > QEMU_SAVE_VERSION) { - /* convert endianness and try again */ - qemuSaveImageBswapHeader(header); - } - - if (header->version > QEMU_SAVE_VERSION) { - virReportError(VIR_ERR_OPERATION_FAILED, - _("image version is not supported (%d > %d)"), - header->version, QEMU_SAVE_VERSION); - return -1; - } - - if (header->data_len <=3D 0) { - virReportError(VIR_ERR_OPERATION_FAILED, - _("invalid header data length: %d"), header->data_l= en); - return -1; - } - - if (header->cookieOffset) - xml_len =3D header->cookieOffset; - else - xml_len =3D header->data_len; - - cookie_len =3D header->data_len - xml_len; - - data->xml =3D g_new0(char, xml_len); - - if (saferead(fd, data->xml, xml_len) !=3D xml_len) { - virReportError(VIR_ERR_OPERATION_FAILED, - "%s", _("failed to read domain XML")); - return -1; - } - - if (cookie_len > 0) { - data->cookie =3D g_new0(char, cookie_len); - - if (saferead(fd, data->cookie, cookie_len) !=3D cookie_len) { - virReportError(VIR_ERR_OPERATION_FAILED, "%s", - _("failed to read cookie")); - return -1; } + return ret; } =20 /* Create a domain from this XML */ @@ -601,7 +632,7 @@ qemuSaveImageStartVM(virConnectPtr conn, virDomainXMLOptionGetSaveCookie(driver->x= mlopt)) < 0) goto cleanup; =20 - if ((header->version =3D=3D 2) && + if ((header->version >=3D 2) && (header->compressed !=3D QEMU_SAVE_FORMAT_RAW)) { if (!(cmd =3D qemuSaveImageGetCompressionCommand(header->compresse= d))) goto cleanup; diff --git a/src/qemu/qemu_saveimage.h b/src/qemu/qemu_saveimage.h index 391cd55ed0..58d0949b9c 100644 --- a/src/qemu/qemu_saveimage.h +++ b/src/qemu/qemu_saveimage.h @@ -30,20 +30,20 @@ */ #define QEMU_SAVE_MAGIC "LibvirtQemudSave" #define QEMU_SAVE_PARTIAL "LibvirtQemudPart" -#define QEMU_SAVE_VERSION 2 +#define QEMU_SAVE_VERSION 3 =20 G_STATIC_ASSERT(sizeof(QEMU_SAVE_MAGIC) =3D=3D sizeof(QEMU_SAVE_PARTIAL)); =20 typedef struct _virQEMUSaveHeader virQEMUSaveHeader; struct _virQEMUSaveHeader { - char magic[sizeof(QEMU_SAVE_MAGIC)-1]; - uint32_t version; - uint32_t data_len; - uint32_t was_running; - uint32_t compressed; - uint32_t cookieOffset; - uint32_t unused[14]; -}; + char magic[sizeof(QEMU_SAVE_MAGIC)-1]; /* 16 bytes */ + uint32_t version; /* 4 bytes */ + uint32_t data_len; /* 4 bytes */ + uint32_t was_running; /* 4 bytes */ + uint32_t compressed; /* 4 bytes */ + uint32_t cookieOffset; /* 4 bytes */ + uint32_t unused[14]; /* 56 bytes */ +} ATTRIBUTE_PACKED; /* =3D 92 bytes */ =20 =20 typedef struct _virQEMUSaveData virQEMUSaveData; @@ -103,6 +103,10 @@ int virQEMUSaveDataWrite(virQEMUSaveData *data, int fd, const char *path); +int +virQEMUSaveDataRead(virQEMUSaveData *data, + int fd, + const char *path); =20 virQEMUSaveData * virQEMUSaveDataNew(char *domXML, --=20 2.35.3