From nobody Wed May 1 22:27:36 2024 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1600079591; cv=none; d=zohomail.com; s=zohoarc; b=ID1qel5f110v5HCUzBgiEgy2FsBRxg0GYBOOYxFF+W51hxqJAH6IhiK8/nYjDDN1m431pCV0/2RmnTYfhG4lvgXFhKj8fbr/QiYYDmw+gDbW2N9rog5i01Uas374K2NdcudTvH9hDEobBbpD3KIWboi2Lv0S71EfyN5hrgo4v24= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1600079591; h=Content-Type:Content-Transfer-Encoding:Cc:Date:From:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:Sender:Subject:To; bh=Fle0bSrXP9esjMoswH7JR0vVF4fePVd2FffhvZ0/LD0=; b=jQWQttwUzUJHRVhiqAd37tJq/Dc9Vd/53IPYBiQTyMo/gyBcloJYXqXVEpIO2bAp2AByHMsEdFxBCQUipIDFqjL69OHKofV0s18xRhNHMeFDZOepsW8gGv0xdOySy0LiUvQssIBowZt5o89qdaK/WMmYEyNX0QQCluPn2/kMCbY= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail header.from= (p=none dis=none) header.from= Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1600079591991124.30745983043153; Mon, 14 Sep 2020 03:33:11 -0700 (PDT) Received: from localhost ([::1]:47942 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kHlnK-0002K8-TS for importer@patchew.org; Mon, 14 Sep 2020 06:33:10 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:36362) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kHlll-0001ES-Bd for qemu-devel@nongnu.org; Mon, 14 Sep 2020 06:31:33 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:40630) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kHlli-0001XY-Bp for qemu-devel@nongnu.org; Mon, 14 Sep 2020 06:31:33 -0400 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-190-CKjzUam8NZOqznT-nRBBIg-1; Mon, 14 Sep 2020 06:31:20 -0400 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id EC7061008567 for ; Mon, 14 Sep 2020 10:31:19 +0000 (UTC) Received: from localhost.localdomain.com (ovpn-114-99.ams2.redhat.com [10.36.114.99]) by smtp.corp.redhat.com (Postfix) with ESMTP id 38001100EBC0; Mon, 14 Sep 2020 10:31:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1600079484; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=Fle0bSrXP9esjMoswH7JR0vVF4fePVd2FffhvZ0/LD0=; b=fdVUyTYkJib7qk/NygLOvufatdh/FAuhRuEnz51ageTsA0GY+HCNa8RmG30uFOLCjkBJ5N VHAJ0fEWRuXryp7tw5ft9hwicY/ESoH6VZKeYqIOBHclXSNeQ9SpbStBxvT7IQ6w7sL+wP 7KQSPOB3a+IUQxhADyZf3qVGX3tnV7Y= X-MC-Unique: CKjzUam8NZOqznT-nRBBIg-1 From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= To: qemu-devel@nongnu.org Subject: [PATCH] char: fix logging when chardev write fails Date: Mon, 14 Sep 2020 11:31:09 +0100 Message-Id: <20200914103109.1327875-1-berrange@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=berrange@redhat.com X-Mimecast-Spam-Score: 0.002 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=63.128.21.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/09/14 02:55:39 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -38 X-Spam_score: -3.9 X-Spam_bar: --- X-Spam_report: (-3.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1.792, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Paolo Bonzini , =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= , =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) The qemu_chr_write_buffer() method sends data to the chardev backend for writing, and then also writes to the log file. In case the chardev backend only writes part of the data buffer, we need to make sure we only log the same subset. qemu_chr_write_buffer() will be invoked again later to write the rest of the buffer. In the case the chardev backend returns an error though, no further attempts to likely to be made to write the data. We must therefore write the entire buffer to the log immediately. An example where this is important is with the socket backend. This will return -1 for all writes if no client is currently connected. We still wish to write data to the log file when no client is present though. This used to work because the chardev would return "len" to pretend it had written all data when no client is connected, but this changed to return an error in commit 271094474b65de1ad7aaf729938de3d9b9d0d36f Author: Dima Stepanov Date: Thu May 28 12:11:18 2020 +0300 char-socket: return -1 in case of disconnect during tcp_chr_write and this broke the logging, resulting in all data being discarded when no client is present. Fixes: https://bugs.launchpad.net/qemu/+bug/1893691 Signed-off-by: Daniel P. Berrang=C3=A9 Reviewed-by: Marc-Andr=C3=A9 Lureau --- chardev/char.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/chardev/char.c b/chardev/char.c index 77e7ec814f..e30cd025f5 100644 --- a/chardev/char.c +++ b/chardev/char.c @@ -138,7 +138,20 @@ static int qemu_chr_write_buffer(Chardev *s, } } if (*offset > 0) { + /* + * If some data was written by backend, we should + * only log what was actually written. This method + * may be invoked again to write the remaining + * method, thus we'll log the remainder at that time. + */ qemu_chr_write_log(s, buf, *offset); + } else if (res < 0) { + /* + * If a fatal error was reported by the backend, + * assume this method won't be invoked again with + * this buffer, so log it all right away. + */ + qemu_chr_write_log(s, buf, len); } qemu_mutex_unlock(&s->chr_write_lock); =20 --=20 2.26.2