From patchwork Mon Jul 17 14:55:43 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Denis V. Lunev" X-Patchwork-Id: 1808786 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4R4QC92d5Xz20Ct for ; Tue, 18 Jul 2023 00:56:35 +1000 (AEST) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qLPdk-0002Pw-Og; Mon, 17 Jul 2023 10:55:56 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qLPdh-0002Nb-JX; Mon, 17 Jul 2023 10:55:53 -0400 Received: from relay.virtuozzo.com ([130.117.225.111]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qLPde-0003nN-0y; Mon, 17 Jul 2023 10:55:52 -0400 Received: from ch-vpn.virtuozzo.com ([130.117.225.6] helo=iris.sw.ru) by relay.virtuozzo.com with esmtp (Exim 4.96) (envelope-from ) id 1qLPc2-00HTc0-0q; Mon, 17 Jul 2023 16:55:39 +0200 From: "Denis V. Lunev" To: qemu-block@nongnu.org, qemu-devel@nongnu.org Cc: den@openvz.org, Eric Blake , Vladimir Sementsov-Ogievskiy Subject: [PATCH 4/5] qemu-nbd: properly report error if qemu_daemon() is failed Date: Mon, 17 Jul 2023 16:55:43 +0200 Message-Id: <20230717145544.194786-5-den@openvz.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230717145544.194786-1-den@openvz.org> References: <20230717145544.194786-1-den@openvz.org> MIME-Version: 1.0 Received-SPF: pass client-ip=130.117.225.111; envelope-from=den@openvz.org; helo=relay.virtuozzo.com X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org errno has been overwritten by dup2() just below qemu_daemon() and thus improperly returned to the caller. Fix accordingly. Signed-off-by: Denis V. Lunev CC: Eric Blake CC: Vladimir Sementsov-Ogievskiy Reviewed-by: Eric Blake --- qemu-nbd.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/qemu-nbd.c b/qemu-nbd.c index 4450cc826b..f27613cb57 100644 --- a/qemu-nbd.c +++ b/qemu-nbd.c @@ -932,9 +932,12 @@ int main(int argc, char **argv) error_report("Failed to fork: %s", strerror(errno)); exit(EXIT_FAILURE); } else if (pid == 0) { + int saved_errno; + close(stderr_fd[0]); ret = qemu_daemon(1, 0); + saved_errno = errno; /* dup2 will overwrite error below */ /* Temporarily redirect stderr to the parent's pipe... */ if (dup2(stderr_fd[1], STDERR_FILENO) < 0) { @@ -952,7 +955,7 @@ int main(int argc, char **argv) } if (ret < 0) { - error_report("Failed to daemonize: %s", strerror(errno)); + error_report("Failed to daemonize: %s", strerror(saved_errno)); exit(EXIT_FAILURE); }