From nobody Fri Apr 11 23:10:54 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zoho.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1496071013601769.4690799120501; Mon, 29 May 2017 08:16:53 -0700 (PDT) Received: from localhost ([::1]:49162 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dFMPa-0000uf-UL for importer@patchew.org; Mon, 29 May 2017 11:16:50 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45838) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dFMGZ-0001Z6-78 for qemu-devel@nongnu.org; Mon, 29 May 2017 11:07:32 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dFMGX-0006WU-Nd for qemu-devel@nongnu.org; Mon, 29 May 2017 11:07:31 -0400 Received: from mx1.redhat.com ([209.132.183.28]:38668) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dFMGS-0006Vh-Oy; Mon, 29 May 2017 11:07:24 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id C02E980F91; Mon, 29 May 2017 15:07:23 +0000 (UTC) Received: from noname.redhat.com (ovpn-117-181.ams2.redhat.com [10.36.117.181]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9DDBE78DD7; Mon, 29 May 2017 15:07:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com C02E980F91 Authentication-Results: ext-mx03.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx03.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=kwolf@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com C02E980F91 From: Kevin Wolf To: qemu-block@nongnu.org Date: Mon, 29 May 2017 17:06:54 +0200 Message-Id: <1496070414-6744-16-git-send-email-kwolf@redhat.com> In-Reply-To: <1496070414-6744-1-git-send-email-kwolf@redhat.com> References: <1496070414-6744-1-git-send-email-kwolf@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Mon, 29 May 2017 15:07:23 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PULL 15/15] block/file-*: *_parse_filename() and colons X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" From: Max Reitz The file drivers' *_parse_filename() implementations just strip the optional protocol prefix off the filename. However, for e.g. "file:foo:bar", this would lead to "foo:bar" being stored as the BDS's filename which looks like it should be managed using the "foo" protocol. This is especially troublesome if you then try to resolve a backing filename based on "foo:bar". This issue can only occur if the stripped part is a relative filename ("file:/foo:bar" will be shortened to "/foo:bar" and having a slash before the first colon means that "/foo" is not recognized as a protocol part). Therefore, we can easily fix it by prepending "./" to such filenames. Before this patch: $ ./qemu-img create -f qcow2 backing.qcow2 64M Formatting 'backing.qcow2', fmt=3Dqcow2 size=3D67108864 encryption=3Doff cluster_size=3D65536 lazy_refcounts=3Doff refcount_bits=3D16 $ ./qemu-img create -f qcow2 -b backing.qcow2 file:top:image.qcow2 Formatting 'file:top:image.qcow2', fmt=3Dqcow2 size=3D67108864 backing_file=3Dbacking.qcow2 encryption=3Doff cluster_size=3D65536 lazy_refcounts=3Doff refcount_bits=3D16 $ ./qemu-io file:top:image.qcow2 can't open device file:top:image.qcow2: Could not open backing file: Unknown protocol 'top' After this patch: $ ./qemu-io file:top:image.qcow2 [no error] Signed-off-by: Max Reitz Message-id: 20170522195217.12991-3-mreitz@redhat.com Reviewed-by: Eric Blake Signed-off-by: Max Reitz --- block.c | 35 +++++++++++++++++++++++++++++++++++ block/file-posix.c | 17 +++-------------- block/file-win32.c | 12 ++---------- include/block/block_int.h | 3 +++ 4 files changed, 43 insertions(+), 24 deletions(-) diff --git a/block.c b/block.c index b72b872..fa1d06d 100644 --- a/block.c +++ b/block.c @@ -197,6 +197,41 @@ void path_combine(char *dest, int dest_size, } } =20 +/* + * Helper function for bdrv_parse_filename() implementations to remove opt= ional + * protocol prefixes (especially "file:") from a filename and for putting = the + * stripped filename into the options QDict if there is such a prefix. + */ +void bdrv_parse_filename_strip_prefix(const char *filename, const char *pr= efix, + QDict *options) +{ + if (strstart(filename, prefix, &filename)) { + /* Stripping the explicit protocol prefix may result in a protocol + * prefix being (wrongly) detected (if the filename contains a col= on) */ + if (path_has_protocol(filename)) { + QString *fat_filename; + + /* This means there is some colon before the first slash; ther= efore, + * this cannot be an absolute path */ + assert(!path_is_absolute(filename)); + + /* And we can thus fix the protocol detection issue by prefixi= ng it + * by "./" */ + fat_filename =3D qstring_from_str("./"); + qstring_append(fat_filename, filename); + + assert(!path_has_protocol(qstring_get_str(fat_filename))); + + qdict_put(options, "filename", fat_filename); + } else { + /* If no protocol prefix was detected, we can use the shortened + * filename as-is */ + qdict_put_str(options, "filename", filename); + } + } +} + + /* Returns whether the image file is opened as read-only. Note that this c= an * return false and writing to the image file is still not possible becaus= e the * image is inactivated. */ diff --git a/block/file-posix.c b/block/file-posix.c index 4354d49..de2d3a2 100644 --- a/block/file-posix.c +++ b/block/file-posix.c @@ -381,12 +381,7 @@ static void raw_parse_flags(int bdrv_flags, int *open_= flags) static void raw_parse_filename(const char *filename, QDict *options, Error **errp) { - /* The filename does not have to be prefixed by the protocol name, sin= ce - * "file" is the default protocol; therefore, the return value of this - * function call can be ignored. */ - strstart(filename, "file:", &filename); - - qdict_put_str(options, "filename", filename); + bdrv_parse_filename_strip_prefix(filename, "file:", options); } =20 static QemuOptsList raw_runtime_opts =3D { @@ -2395,10 +2390,7 @@ static int check_hdev_writable(BDRVRawState *s) static void hdev_parse_filename(const char *filename, QDict *options, Error **errp) { - /* The prefix is optional, just as for "file". */ - strstart(filename, "host_device:", &filename); - - qdict_put_str(options, "filename", filename); + bdrv_parse_filename_strip_prefix(filename, "host_device:", options); } =20 static bool hdev_is_sg(BlockDriverState *bs) @@ -2697,10 +2689,7 @@ static BlockDriver bdrv_host_device =3D { static void cdrom_parse_filename(const char *filename, QDict *options, Error **errp) { - /* The prefix is optional, just as for "file". */ - strstart(filename, "host_cdrom:", &filename); - - qdict_put_str(options, "filename", filename); + bdrv_parse_filename_strip_prefix(filename, "host_cdrom:", options); } #endif =20 diff --git a/block/file-win32.c b/block/file-win32.c index 8f14f0b..ef2910b 100644 --- a/block/file-win32.c +++ b/block/file-win32.c @@ -276,12 +276,7 @@ static void raw_parse_flags(int flags, bool use_aio, i= nt *access_flags, static void raw_parse_filename(const char *filename, QDict *options, Error **errp) { - /* The filename does not have to be prefixed by the protocol name, sin= ce - * "file" is the default protocol; therefore, the return value of this - * function call can be ignored. */ - strstart(filename, "file:", &filename); - - qdict_put_str(options, "filename", filename); + bdrv_parse_filename_strip_prefix(filename, "file:", options); } =20 static QemuOptsList raw_runtime_opts =3D { @@ -671,10 +666,7 @@ static int hdev_probe_device(const char *filename) static void hdev_parse_filename(const char *filename, QDict *options, Error **errp) { - /* The prefix is optional, just as for "file". */ - strstart(filename, "host_device:", &filename); - - qdict_put_str(options, "filename", filename); + bdrv_parse_filename_strip_prefix(filename, "host_device:", options); } =20 static int hdev_open(BlockDriverState *bs, QDict *options, int flags, diff --git a/include/block/block_int.h b/include/block/block_int.h index 8d3724c..e5eb473 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -682,6 +682,9 @@ int get_tmp_filename(char *filename, int size); BlockDriver *bdrv_probe_all(const uint8_t *buf, int buf_size, const char *filename); =20 +void bdrv_parse_filename_strip_prefix(const char *filename, const char *pr= efix, + QDict *options); + =20 /** * bdrv_add_before_write_notifier: --=20 1.8.3.1