From patchwork Mon Feb 5 15:18:16 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Max Reitz X-Patchwork-Id: 869373 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=2001:4830:134:3::11; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3zZsZC5cj4z9s75 for ; Tue, 6 Feb 2018 02:53:23 +1100 (AEDT) Received: from localhost ([::1]:55750 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eij57-0003RB-OG for incoming@patchwork.ozlabs.org; Mon, 05 Feb 2018 10:53:21 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53001) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eiiYN-00007B-Be for qemu-devel@nongnu.org; Mon, 05 Feb 2018 10:19:32 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eiiYK-0006hN-KJ for qemu-devel@nongnu.org; Mon, 05 Feb 2018 10:19:31 -0500 Received: from mx1.redhat.com ([209.132.183.28]:16432) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eiiYC-0006UM-QR; Mon, 05 Feb 2018 10:19:20 -0500 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 1B3897E42C; Mon, 5 Feb 2018 15:19:20 +0000 (UTC) Received: from localhost (unknown [10.40.205.49]) by smtp.corp.redhat.com (Postfix) with ESMTPS id F1BF26090C; Mon, 5 Feb 2018 15:19:09 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Date: Mon, 5 Feb 2018 16:18:16 +0100 Message-Id: <20180205151835.20812-8-mreitz@redhat.com> In-Reply-To: <20180205151835.20812-1-mreitz@redhat.com> References: <20180205151835.20812-1-mreitz@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 [10.5.110.27]); Mon, 05 Feb 2018 15:19:20 +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] [PATCH v8 07/26] block: bdrv_get_full_backing_filename_from_...'s ret. val. 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: Kevin Wolf , Alberto Garcia , qemu-devel@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" Make bdrv_get_full_backing_filename_from_filename() return an allocated string instead of placing the result in a caller-provided buffer. Signed-off-by: Max Reitz Reviewed-by: Alberto Garcia --- include/block/block.h | 7 +++---- block.c | 51 +++++++++++++++++++++++++++++++++++---------------- block/vmdk.c | 9 ++++----- 3 files changed, 42 insertions(+), 25 deletions(-) diff --git a/include/block/block.h b/include/block/block.h index 993ae74b7e..46ceb1c8d3 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -483,10 +483,9 @@ void bdrv_get_backing_filename(BlockDriverState *bs, char *filename, int filename_size); void bdrv_get_full_backing_filename(BlockDriverState *bs, char *dest, size_t sz, Error **errp); -void bdrv_get_full_backing_filename_from_filename(const char *backed, - const char *backing, - char *dest, size_t sz, - Error **errp); +char *bdrv_get_full_backing_filename_from_filename(const char *backed, + const char *backing, + Error **errp); int path_has_protocol(const char *path); int path_is_absolute(const char *path); diff --git a/block.c b/block.c index 84ab8d4675..6269d25093 100644 --- a/block.c +++ b/block.c @@ -288,20 +288,28 @@ int bdrv_set_read_only(BlockDriverState *bs, bool read_only, Error **errp) return 0; } -void bdrv_get_full_backing_filename_from_filename(const char *backed, - const char *backing, - char *dest, size_t sz, - Error **errp) +/* If @backing is empty, this function returns NULL without setting + * @errp. In all other cases, NULL will only be returned with @errp + * set. + * + * Therefore, a return value of NULL without @errp set means that + * there is no backing file; if @errp is set, there is one but its + * absolute filename cannot be generated. + */ +char *bdrv_get_full_backing_filename_from_filename(const char *backed, + const char *backing, + Error **errp) { - if (backing[0] == '\0' || path_has_protocol(backing) || - path_is_absolute(backing)) - { - pstrcpy(dest, sz, backing); + if (backing[0] == '\0') { + return NULL; + } else if (path_has_protocol(backing) || path_is_absolute(backing)) { + return g_strdup(backing); } else if (backed[0] == '\0' || strstart(backed, "json:", NULL)) { error_setg(errp, "Cannot use relative backing file names for '%s'", backed); + return NULL; } else { - path_combine_deprecated(dest, sz, backed, backing); + return path_combine(backed, backing); } } @@ -309,9 +317,20 @@ void bdrv_get_full_backing_filename(BlockDriverState *bs, char *dest, size_t sz, Error **errp) { char *backed = bs->exact_filename[0] ? bs->exact_filename : bs->filename; + char *full_name; + Error *local_error = NULL; - bdrv_get_full_backing_filename_from_filename(backed, bs->backing_file, - dest, sz, errp); + full_name = bdrv_get_full_backing_filename_from_filename(backed, + bs->backing_file, + &local_error); + if (full_name) { + pstrcpy(dest, sz, full_name); + g_free(full_name); + } else if (local_error) { + error_propagate(errp, local_error); + } else if (sz > 0) { + *dest = '\0'; + } } void bdrv_register(BlockDriver *bdrv) @@ -4647,17 +4666,17 @@ void bdrv_img_create(const char *filename, const char *fmt, size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, img_size); if (backing_file && !(flags & BDRV_O_NO_BACKING)) { BlockDriverState *bs; - char *full_backing = g_new0(char, PATH_MAX); + char *full_backing; int back_flags; QDict *backing_options = NULL; - bdrv_get_full_backing_filename_from_filename(filename, backing_file, - full_backing, PATH_MAX, - &local_err); + full_backing = + bdrv_get_full_backing_filename_from_filename(filename, backing_file, + &local_err); if (local_err) { - g_free(full_backing); goto out; } + assert(full_backing); /* backing files always opened read-only */ back_flags = flags; diff --git a/block/vmdk.c b/block/vmdk.c index 0a0f16d0f0..e61d15bc92 100644 --- a/block/vmdk.c +++ b/block/vmdk.c @@ -2017,16 +2017,15 @@ static int vmdk_create(const char *filename, QemuOpts *opts, Error **errp) } if (backing_file) { BlockBackend *blk; - char *full_backing = g_new0(char, PATH_MAX); - bdrv_get_full_backing_filename_from_filename(filename, backing_file, - full_backing, PATH_MAX, - &local_err); + char *full_backing = + bdrv_get_full_backing_filename_from_filename(filename, backing_file, + &local_err); if (local_err) { - g_free(full_backing); error_propagate(errp, local_err); ret = -ENOENT; goto exit; } + assert(full_backing); blk = blk_new_open(full_backing, NULL, NULL, BDRV_O_NO_BACKING, errp);