From patchwork Fri Oct 5 23:40:02 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Max Reitz X-Patchwork-Id: 10628993 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 62967112B for ; Fri, 5 Oct 2018 23:49:15 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 50D82296BD for ; Fri, 5 Oct 2018 23:49:15 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 447D229709; Fri, 5 Oct 2018 23:49:15 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id B2388296BD for ; Fri, 5 Oct 2018 23:49:14 +0000 (UTC) Received: from localhost ([::1]:37353 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1g8ZqM-0001su-28 for patchwork-qemu-devel@patchwork.kernel.org; Fri, 05 Oct 2018 19:49:14 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57020) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1g8ZiQ-00039Q-Sb for qemu-devel@nongnu.org; Fri, 05 Oct 2018 19:41:07 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1g8ZiO-0008GO-Ut for qemu-devel@nongnu.org; Fri, 05 Oct 2018 19:41:02 -0400 Received: from mx1.redhat.com ([209.132.183.28]:37034) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1g8ZiF-00085e-H3; Fri, 05 Oct 2018 19:40:51 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id CDC4F3082123; Fri, 5 Oct 2018 23:40:50 +0000 (UTC) Received: from localhost (ovpn-204-46.brq.redhat.com [10.40.204.46]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2A47D62926; Fri, 5 Oct 2018 23:40:49 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Date: Sat, 6 Oct 2018 01:40:02 +0200 Message-Id: <20181005234023.8104-11-mreitz@redhat.com> In-Reply-To: <20181005234023.8104-1-mreitz@redhat.com> References: <20181005234023.8104-1-mreitz@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.42]); Fri, 05 Oct 2018 23:40:50 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v11 10/31] 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+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP 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 | 53 ++++++++++++++++++++++++++++++------------- block/vmdk.c | 9 ++++---- qemu-img.c | 12 ++++------ 4 files changed, 48 insertions(+), 33 deletions(-) diff --git a/include/block/block.h b/include/block/block.h index e5f01ebed0..bb238488c4 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -484,10 +484,9 @@ 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 d083b02b58..d31c759091 100644 --- a/block.c +++ b/block.c @@ -293,20 +293,29 @@ 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); } } @@ -314,12 +323,24 @@ void bdrv_get_full_backing_filename(BlockDriverState *bs, char *dest, size_t sz, Error **errp) { char *backed; + char *full_name; + Error *local_error = NULL; bdrv_refresh_filename(bs); backed = bs->exact_filename[0] ? bs->exact_filename : bs->filename; - 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) @@ -4871,17 +4892,17 @@ 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 3d3273e65b..b3fc3b9e12 100644 --- a/block/vmdk.c +++ b/block/vmdk.c @@ -2049,16 +2049,15 @@ static int coroutine_fn vmdk_co_create_opts(const char *filename, QemuOpts *opts } 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); diff --git a/qemu-img.c b/qemu-img.c index b12f4cd19b..22c9abe411 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -3327,18 +3327,14 @@ static int img_rebase(int argc, char **argv) overlay_filename = bs->exact_filename[0] ? bs->exact_filename : bs->filename; - out_real_path = g_malloc(PATH_MAX); - - bdrv_get_full_backing_filename_from_filename(overlay_filename, - out_baseimg, - out_real_path, - PATH_MAX, - &local_err); + out_real_path = + bdrv_get_full_backing_filename_from_filename(overlay_filename, + out_baseimg, + &local_err); if (local_err) { error_reportf_err(local_err, "Could not resolve backing filename: "); ret = -1; - g_free(out_real_path); goto out; }