From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Beller Subject: [PATCHv3 03/13] xread_nonblock: add functionality to read from fds nonblockingly Date: Mon, 21 Sep 2015 15:39:09 -0700 Message-ID: <1442875159-13027-4-git-send-email-sbeller@google.com> References: <1442875159-13027-1-git-send-email-sbeller@google.com> Cc: jacob.keller@gmail.com, peff@peff.net, gitster@pobox.com, jrnieder@gmail.com, johannes.schindelin@gmail.com, Jens.Lehmann@web.de, vlovich@gmail.com, Stefan Beller To: git@vger.kernel.org X-From: git-owner@vger.kernel.org Tue Sep 22 00:39:41 2015 Return-path: Envelope-to: gcvg-git-2@plane.gmane.org Received: from vger.kernel.org ([209.132.180.67]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1Ze9kJ-0006NK-Lh for gcvg-git-2@plane.gmane.org; Tue, 22 Sep 2015 00:39:40 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932983AbbIUWjc (ORCPT ); Mon, 21 Sep 2015 18:39:32 -0400 Received: from mail-pa0-f46.google.com ([209.85.220.46]:36492 "EHLO mail-pa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932692AbbIUWj2 (ORCPT ); Mon, 21 Sep 2015 18:39:28 -0400 Received: by padbj2 with SMTP id bj2so3592038pad.3 for ; Mon, 21 Sep 2015 15:39:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=uIRdVTpffA4AOPa38kRE3uBC5MI+JKj1uxgadFRdd4g=; b=hj3VuryV7Z4QJc+o5VF3gpayjg3hRBxXeg/Q450SdSTsThjtLmYSLJ2v3v5DSXADLG brhAcw5iLsWzxjk99h1PeX2Wmq9nPXsV66j7KxWA7H1XaGg+UE4gK9JHFre/JapDHhEf xTM81pRqt5l8yytEiNazsy+gssK6SxTnVpQ7hpy+F8yZHFd8OTFPsh/EyDb5LX9xWVda e3Vv0n44CtOUxKAu5EigyM0PX8BihBk9inJW4a+uDpEujZgrg1ojbA2EUw8L4oDu2iv8 9mHeQFsSuS1aVvfsKCvi06tsHXbllj8yVzZhh+qamzHyHA5ADyWP6A3d/T5EgZstsVrk PJxA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=uIRdVTpffA4AOPa38kRE3uBC5MI+JKj1uxgadFRdd4g=; b=EahFXZFrq8Huk8aNRt3s2+hXRepdyR9huFXuWDhADFrm/x5PGvoXgZPYGURJDk6o3U WUrjbe8B9bjrHA2f9z4RbfOUAAQmAkR7f8nHiNvkWNMXd5crchEcR5rRvSc4lpfdX4n4 iFF6Yg2sFtgE32ncmy/ulA686/JoIeUnKDPub/KU0Y5aAriJS3qd5lvKGxuZHdoMvQHH l+w/6NNvWOLLJnCwqjXFMq2N1iSHFrIMnHfWFhruqTBvMRXG5c66cGgidvddayvx+z6E TdvIuzmMRzRifhgT2hFGeBovas6WXnfPUPjhy5fPDDGsdQcgA+Dj36B3XDEjiKKSVrF+ 7ncw== X-Gm-Message-State: ALoCoQmI/0dnLBTHADRPN9V12Kesz9PnexGwRmDLhFeYg+8Qas+bpUEb+W9JZWQrh1u54m5xTlPP X-Received: by 10.68.180.131 with SMTP id do3mr27572425pbc.133.1442875167379; Mon, 21 Sep 2015 15:39:27 -0700 (PDT) Received: from localhost ([2620:0:1000:5b00:a032:5a54:ea65:75ca]) by smtp.gmail.com with ESMTPSA id ku8sm26619879pab.0.2015.09.21.15.39.26 (version=TLSv1.2 cipher=RC4-SHA bits=128/128); Mon, 21 Sep 2015 15:39:26 -0700 (PDT) X-Mailer: git-send-email 2.5.0.275.ge015d2a In-Reply-To: <1442875159-13027-1-git-send-email-sbeller@google.com> Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: This wrapper just restarts on EINTR, but not on EAGAIN like xread does. This gives less guarantees on the actual reading rather than on returning fast. Signed-off-by: Stefan Beller --- git-compat-util.h | 1 + wrapper.c | 22 ++++++++++++++++++++++ 2 files changed, 23 insertions(+) diff --git a/git-compat-util.h b/git-compat-util.h index c6d391f..9ccea85 100644 --- a/git-compat-util.h +++ b/git-compat-util.h @@ -718,6 +718,7 @@ extern void *xcalloc(size_t nmemb, size_t size); extern void *xmmap(void *start, size_t length, int prot, int flags, int fd, off_t offset); extern void *xmmap_gently(void *start, size_t length, int prot, int flags, int fd, off_t offset); extern ssize_t xread(int fd, void *buf, size_t len); +extern ssize_t xread_nonblock(int fd, void *buf, size_t len); extern ssize_t xwrite(int fd, const void *buf, size_t len); extern ssize_t xpread(int fd, void *buf, size_t len, off_t offset); extern int xdup(int fd); diff --git a/wrapper.c b/wrapper.c index 50267a4..54ce231 100644 --- a/wrapper.c +++ b/wrapper.c @@ -223,6 +223,28 @@ ssize_t xread(int fd, void *buf, size_t len) } /* + * xread_nonblock() is the same a read(), but it automatically restarts read() + * interrupted operations (EINTR). xread_nonblock() DOES NOT GUARANTEE that + * "len" bytes is read even if the data is available. + */ +ssize_t xread_nonblock(int fd, void *buf, size_t len) +{ + ssize_t nr; + if (len > MAX_IO_SIZE) + len = MAX_IO_SIZE; + while (1) { + nr = read(fd, buf, len); + if (nr < 0) { + if (errno == EINTR) + continue; + if (errno == EWOULDBLOCK) + errno = EAGAIN; + } + return nr; + } +} + +/* * xwrite() is the same a write(), but it automatically restarts write() * operations with a recoverable error (EAGAIN and EINTR). xwrite() DOES NOT * GUARANTEE that "len" bytes is written even if the operation is successful. -- 2.5.0.275.ge015d2a