From nobody Tue Nov 4 15:16:11 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.zohomail.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 (208.118.235.17 [208.118.235.17]) by mx.zohomail.com with SMTPS id 1530492660133180.5809980667516; Sun, 1 Jul 2018 17:51:00 -0700 (PDT) Received: from localhost ([::1]:56134 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fZn3F-00038z-IG for importer@patchew.org; Sun, 01 Jul 2018 20:50:45 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54557) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fZn2I-0002kf-DX for qemu-devel@nongnu.org; Sun, 01 Jul 2018 20:49:49 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fZn2F-00081W-AI for qemu-devel@nongnu.org; Sun, 01 Jul 2018 20:49:46 -0400 Received: from [45.249.212.35] (port=45075 helo=huawei.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fZn2E-0007yG-Tn for qemu-devel@nongnu.org; Sun, 01 Jul 2018 20:49:43 -0400 Received: from DGGEMS412-HUB.china.huawei.com (unknown [172.30.72.59]) by Forcepoint Email with ESMTP id 7E44952246C83; Mon, 2 Jul 2018 08:49:33 +0800 (CST) Received: from localhost (10.177.25.200) by DGGEMS412-HUB.china.huawei.com (10.3.19.212) with Microsoft SMTP Server id 14.3.382.0; Mon, 2 Jul 2018 08:49:26 +0800 From: xinhua.Cao To: , , , , Date: Mon, 2 Jul 2018 08:49:10 +0800 Message-ID: <20180702004910.13216-1-caoxinhua@huawei.com> X-Mailer: git-send-email 2.8.3 MIME-Version: 1.0 X-Originating-IP: [10.177.25.200] X-CFilter-Loop: Reflected X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [fuzzy] X-Received-From: 45.249.212.35 Subject: [Qemu-devel] [PATCH] qemu-char: reset errno before qemu char write or read action 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: "xinhua.Cao" , weidong.huang@huawei.com, weifuqiang@huawei.com, qemu-devel@nongnu.org, king.wang@huawei.com, liuyongan@huawei.com, arei.gonglei@huawei.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 Content-Type: text/plain; charset="utf-8" In the tcp_chr_write function, we checked errno, but errno was not reset before a read or write operation. Therefore, this check of errno's actions is often incorrect after EAGAIN has occurred. We reset errno before reading and writing to ensure the correctness of errno's judgment Signed-off-by: xinhua.Cao Reviewed-by: Philippe Mathieu-Daud=C3=A9 --- chardev/char-fe.c | 1 + chardev/char.c | 2 ++ 2 files changed, 3 insertions(+) diff --git a/chardev/char-fe.c b/chardev/char-fe.c index b1f228e..d96ca6f 100644 --- a/chardev/char-fe.c +++ b/chardev/char-fe.c @@ -69,6 +69,7 @@ int qemu_chr_fe_read_all(CharBackend *be, uint8_t *buf, i= nt len) =20 while (offset < len) { retry: + errno =3D 0; res =3D CHARDEV_GET_CLASS(s)->chr_sync_read(s, buf + offset, len - offset); if (res =3D=3D -1 && errno =3D=3D EAGAIN) { diff --git a/chardev/char.c b/chardev/char.c index 76d866e..3387442 100644 --- a/chardev/char.c +++ b/chardev/char.c @@ -85,6 +85,7 @@ static void qemu_chr_write_log(Chardev *s, const uint8_t = *buf, size_t len) =20 while (done < len) { retry: + errno =3D 0; ret =3D write(s->logfd, buf + done, len - done); if (ret =3D=3D -1 && errno =3D=3D EAGAIN) { g_usleep(100); @@ -109,6 +110,7 @@ static int qemu_chr_write_buffer(Chardev *s, qemu_mutex_lock(&s->chr_write_lock); while (*offset < len) { retry: + errno =3D 0; res =3D cc->chr_write(s, buf + *offset, len - *offset); if (res < 0 && errno =3D=3D EAGAIN && write_all) { g_usleep(100); --=20 2.8.3