From nobody Sun Oct 5 21:12:40 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 1496689884595871.9847496488946; Mon, 5 Jun 2017 12:11:24 -0700 (PDT) Received: from localhost ([::1]:34776 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dHxPO-0002aZ-Aw for importer@patchew.org; Mon, 05 Jun 2017 15:11:22 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35156) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dHxMi-0000Z4-Se for qemu-devel@nongnu.org; Mon, 05 Jun 2017 15:08:38 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dHxMh-00043K-Qr for qemu-devel@nongnu.org; Mon, 05 Jun 2017 15:08:36 -0400 Received: from mx1.redhat.com ([209.132.183.28]:33282) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dHxMf-0003zr-Cc; Mon, 05 Jun 2017 15:08:33 -0400 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 7C0053B708; Mon, 5 Jun 2017 19:08:32 +0000 (UTC) Received: from red.redhat.com (ovpn-120-12.rdu2.redhat.com [10.10.120.12]) by smtp.corp.redhat.com (Postfix) with ESMTP id D5C0317DFA; Mon, 5 Jun 2017 19:08:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 7C0053B708 Authentication-Results: ext-mx06.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx06.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=eblake@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 7C0053B708 From: Eric Blake To: qemu-devel@nongnu.org Date: Mon, 5 Jun 2017 14:08:21 -0500 Message-Id: <20170605190824.25184-2-eblake@redhat.com> In-Reply-To: <20170605190824.25184-1-eblake@redhat.com> References: <20170605190824.25184-1-eblake@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 [10.5.110.30]); Mon, 05 Jun 2017 19:08:32 +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 v3 1/4] qemu-io: Don't die on second open 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 , jsnow@redhat.com, qemu-block@nongnu.org, mreitz@redhat.com 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" Most callback commands in qemu-io return 0 to keep the interpreter loop running, or 1 to quit immediately. However, open_f() just passed through the return value of openfile(), which has different semantics of returning 0 if a file was opened, or 1 on any failure. As a result of mixing the return semantics, we are forcing the qemu-io interpreter to exit early on any failures, which is rather annoying when some of the failures are obviously trying to give the user a hint of how to proceed (if we didn't then kill qemu-io out from under the user's feet): $ qemu-io qemu-io> open foo qemu-io> open foo file open already, try 'help close' $ echo $? 0 In general, we WANT openfile() to report failures, since it is the function used in the form 'qemu-io -c "$something" no_such_file' for performing one or more -c options on a single file, and it is not worth attempting $something if the file itself cannot be opened. So the solution is to fix open_f() to always return 0 (when we are in interactive mode, even failure to open should not end the session), and save the return value of openfile() for command line use in main(). Note, however, that we do have some qemu-iotests that do 'qemu-io -c "open file" -c "$something"'; such tests will now proceed to attempt $something whether or not the open succeeded, the same way as if the two commands had been attempted in interactive mode; but it also means that it is now possible to use -c close and have a single qemu-io command line operate on more than one file even without using interactive mode. Although the '-c open' action is a subtle change in behavior, remember that qemu-io is for debugging purposes, so as long as it serves the needs of qemu-iotests while still being reasonable for interactive use, it should not be a problem. This has been awkward since at least as far back as commit e3aff4f, in 2009. Signed-off-by: Eric Blake Reviewed-by: Fam Zheng --- v3: tweak commit message to distinguish that '-c open' has a subtle new behavior from the command line v2: fix open_f(), not openfile() --- qemu-io.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/qemu-io.c b/qemu-io.c index 8e38b28..8074656 100644 --- a/qemu-io.c +++ b/qemu-io.c @@ -230,13 +230,14 @@ static int open_f(BlockBackend *blk, int argc, char *= *argv) qemu_opts_reset(&empty_opts); if (optind =3D=3D argc - 1) { - return openfile(argv[optind], flags, writethrough, force_share, op= ts); + openfile(argv[optind], flags, writethrough, force_share, opts); } else if (optind =3D=3D argc) { - return openfile(NULL, flags, writethrough, force_share, opts); + openfile(NULL, flags, writethrough, force_share, opts); } else { QDECREF(opts); - return qemuio_command_usage(&open_cmd); + qemuio_command_usage(&open_cmd); } + return 0; } static int quit_f(BlockBackend *blk, int argc, char **argv) --=20 2.9.4