From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 39C93C433F5 for ; Thu, 6 Oct 2022 08:19:29 +0000 (UTC) Received: from localhost ([::1]:54746 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ogM6K-0003Jl-8f for qemu-devel@archiver.kernel.org; Thu, 06 Oct 2022 04:19:28 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:55608) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ogLzg-0006LX-QT for qemu-devel@nongnu.org; Thu, 06 Oct 2022 04:12:39 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:56344) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ogLze-0002oW-QY for qemu-devel@nongnu.org; Thu, 06 Oct 2022 04:12:35 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1665043952; 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: in-reply-to:in-reply-to:references:references; bh=XExzAlB9hioR6/71riasaaqxWc+GgRvUIex+5d/LKR4=; b=PdaZLum5c7bDLfVF7Zj33OQ9nlKkEkJdV8MWXrv2QxElN1lSXjKyfxknn4Mzv0310JChSf qKmNeQJRDYU3wGe4VxCluE74LfwP4KpNjWpOB/Bmfu6Ci1liN2lRDcaogQ9boi2MzhYnGt lZ8oQvhSI0vtIAF+BV8OmNHOCqVnlIw= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-644-_5QyKeMgMNCNc26MZIurCw-1; Thu, 06 Oct 2022 04:12:31 -0400 X-MC-Unique: _5QyKeMgMNCNc26MZIurCw-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id E5F7E185A794 for ; Thu, 6 Oct 2022 08:12:30 +0000 (UTC) Received: from localhost (unknown [10.39.208.20]) by smtp.corp.redhat.com (Postfix) with ESMTP id 40EBD40C6F9F; Thu, 6 Oct 2022 08:12:29 +0000 (UTC) From: marcandre.lureau@redhat.com To: qemu-devel@nongnu.org Cc: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= , =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= Subject: [PATCH v3 1/5] osdep: make readv_writev() work with partial read/write Date: Thu, 6 Oct 2022 12:12:18 +0400 Message-Id: <20221006081222.2606746-2-marcandre.lureau@redhat.com> In-Reply-To: <20221006081222.2606746-1-marcandre.lureau@redhat.com> References: <20221006081222.2606746-1-marcandre.lureau@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 Received-SPF: pass client-ip=170.10.133.124; envelope-from=marcandre.lureau@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, 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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" From: Marc-André Lureau With a pipe or other reasons, read/write may return less than the requested bytes. This happens with the test-io-channel-command test on Windows. glib spawn code uses a binary pipe of 4096 bytes, and the first read returns that much (although more are requested), for some unclear reason... Signed-off-by: Marc-André Lureau --- util/osdep.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/util/osdep.c b/util/osdep.c index 60fcbbaebe..b85715a743 100644 --- a/util/osdep.c +++ b/util/osdep.c @@ -544,12 +544,17 @@ readv_writev(int fd, const struct iovec *iov, int iov_cnt, bool do_write) { unsigned i = 0; ssize_t ret = 0; + ssize_t off = 0; while (i < iov_cnt) { ssize_t r = do_write - ? write(fd, iov[i].iov_base, iov[i].iov_len) - : read(fd, iov[i].iov_base, iov[i].iov_len); + ? write(fd, iov[i].iov_base + off, iov[i].iov_len - off) + : read(fd, iov[i].iov_base + off, iov[i].iov_len - off); if (r > 0) { ret += r; + off += r; + if (off < iov[i].iov_len) { + continue; + } } else if (!r) { break; } else if (errno == EINTR) { @@ -562,6 +567,7 @@ readv_writev(int fd, const struct iovec *iov, int iov_cnt, bool do_write) } break; } + off = 0; i++; } return ret; -- 2.37.3