From patchwork Fri Oct 18 05:29:52 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeff King X-Patchwork-Id: 13841093 Received: from cloud.peff.net (cloud.peff.net [104.130.231.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5388F15DBB3 for ; Fri, 18 Oct 2024 05:29:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=104.130.231.41 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729229396; cv=none; b=pNl23vZydzfyCxSwrF+IH8O3DuYJn4gLq5p8ceNIRcJCA2M1Kq2QX05zN8CgUeN1c9rLyXKIn/iIhG9z8Fh0UQG+nORqOYkKlkDDyq83I9zjnVxXa2pUPqhTAICov160skQZ+Uc8d9085rlVUhF32j+VFNkSAjf2+/mUc5Sn6Cg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729229396; c=relaxed/simple; bh=tS6WBpZtcPUcgogJ+06KoJz+ZnHHH/J/Ku56vsYbo7k=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=alPgxUB+aFwBKxWOi20xSLBFqtgagswSoF5sKa7YVFv59gBZSwPZYMZTVTSBoR6i0wntR1tQWiK0cz5tIQIsqZi/miX5695eKx4uNcxOKTN3WMbgw4SPrQ8W7jNePlIo5CQT44qS+sn4x2rZcu4l4uaDgmERMEwdMIPGsfsQyvc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=peff.net; spf=pass smtp.mailfrom=peff.net; dkim=pass (2048-bit key) header.d=peff.net header.i=@peff.net header.b=SSJOYSWB; arc=none smtp.client-ip=104.130.231.41 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=peff.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=peff.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=peff.net header.i=@peff.net header.b="SSJOYSWB" Received: (qmail 32363 invoked by uid 109); 18 Oct 2024 05:29:53 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed; d=peff.net; h=date:from:to:cc:subject:message-id:references:mime-version:content-type:in-reply-to; s=20240930; bh=tS6WBpZtcPUcgogJ+06KoJz+ZnHHH/J/Ku56vsYbo7k=; b=SSJOYSWBOaTmkOtUn9bYls50S9s3uEnKDNV2INA8P3Nea3vCvyKsaMjGhXB75gZmtOm9+H7ACkHO+/WdyWzQqLvPaJlWY1mIL2G+6CQK4L9wHOc45vuwZhdPLznoT9oqQcPcvUL9AJubfVQcX8qGqTYeBb5wEWg75c/qNA3znQQnQLcgFwesAtLtfVOyIHAPdHUctmPCkmQLp62Zrr/HKRsjyiKI+tFZDLtAB2MIBTVYr6yIgHBHpoUwguBVEjyb5bFXA3ktmzLeuXYhl2efuECyt4wHzY16T/6312NniY6RX8+ubqLhZJ68n2GIXOog25R+BYQUwkd0kGfutRWcGg== Received: from Unknown (HELO peff.net) (10.0.1.2) by cloud.peff.net (qpsmtpd/0.94) with ESMTP; Fri, 18 Oct 2024 05:29:53 +0000 Authentication-Results: cloud.peff.net; auth=none Received: (qmail 13152 invoked by uid 111); 18 Oct 2024 05:29:52 -0000 Received: from coredump.intra.peff.net (HELO coredump.intra.peff.net) (10.0.0.2) by peff.net (qpsmtpd/0.94) with (TLS_AES_256_GCM_SHA384 encrypted) ESMTPS; Fri, 18 Oct 2024 01:29:52 -0400 Authentication-Results: peff.net; auth=none Date: Fri, 18 Oct 2024 01:29:52 -0400 From: Jeff King To: Patrick Steinhardt Cc: git@vger.kernel.org, Adam Dinwoodie , Ramsay Jones , Taylor Blau Subject: [PATCH] credential-cache: treat ECONNABORTED like ECONNRESET Message-ID: <20241018052952.GE2408674@coredump.intra.peff.net> References: <658fe4fa540a0a5316e11ed43f9139d5ef818ee5.1729226155.git.ps@pks.im> Precedence: bulk X-Mailing-List: git@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <658fe4fa540a0a5316e11ed43f9139d5ef818ee5.1729226155.git.ps@pks.im> On Fri, Oct 18, 2024 at 06:36:11AM +0200, Patrick Steinhardt wrote: > Subject: builtin/credential-cache--daemon: fix error when "exit"ing on Cygwin I think this commit message has a few unclear or inaccurate bits, because it's based on the earlier attempt. E.g., the change is now on the client side, not in credential-cache--daemon. And I think rather than say "the daemon exit rules are intricate", we can actually outline the rules. :) So here's what I had written after reading through the old thread. It would preferably get Ramsay's Signed-off-by before being applied. -- >8 -- From: Ramsay Jones Subject: [PATCH] credential-cache: treat ECONNABORTED like ECONNRESET On Cygwin, t0301 fails because "git credential-cache exit" returns a non-zero exit code. What's supposed to happen here is: 1. The client (the "credential-cache" invocation above) connects to a previously-spawned credential-cache--daemon. 2. The client sends an "exit" command to the daemon. 3. The daemon unlinks the socket and then exits, closing the descriptor back to the client. 4. The client sees EOF on the descriptor and exits successfully. That works on most platforms, and even _used_ to work on Cygwin. But that changed in Cygwin's ef95c03522 (Cygwin: select: Fix FD_CLOSE handling, 2021-04-06). After that commit, the client sees a read error with errno set to ECONNABORTED, and it reports the error and dies. It's not entirely clear if this is a Cygwin bug. It seems that calling fclose() on the filehandles pointing to the sockets is sufficient to avoid this error return, even though exiting should in general look the same from the client's perspective. However, we can't just call fclose() here. It's important in step 3 above to unlink the socket before closing the descriptor to avoid the race mentioned by 7d5e9c9849 (credential-cache--daemon: clarify "exit" action semantics, 2016-03-18). The client will exit as soon as it sees the descriptor close, and the daemon may or may not have actually unlinked the socket by then. That makes test code like this: git credential exit && test_path_is_missing .git-credential-cache racy. So we probably _could_ fix this by calling: delete_tempfile(&socket_file); fclose(in); fclose(out); before we exit(). Or by replacing the exit() with a return up the stack, in which case the fclose() happens as we unwind. But in that case we'd still need to call delete_tempfile() here to avoid the race. But simpler still is that we can notice that we already special-case ECONNRESET on the client side, courtesy of 1f180e5eb9 (credential-cache: interpret an ECONNRESET as an EOF, 2017-07-27). We can just do the same thing here (I suspect that prior to the Cygwin commit that introduced this problem, we were really just seeing ECONNRESET instead of ECONNABORTED, so the "new" problem is just the switch of the errno values). There's loads more debugging in this thread: https://lore.kernel.org/git/9dc3e85f-a532-6cff-de11-1dfb2e4bc6b6@ramsayjones.plus.com/ but I've tried to summarize the useful bits in this commit message. [jk: commit message] Signed-off-by: Jeff King --- builtin/credential-cache.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/builtin/credential-cache.c b/builtin/credential-cache.c index 5de8b9123b..7789d57d3e 100644 --- a/builtin/credential-cache.c +++ b/builtin/credential-cache.c @@ -30,7 +30,7 @@ static int connection_fatally_broken(int error) static int connection_closed(int error) { - return (error == ECONNRESET); + return error == ECONNRESET || error == ECONNABORTED; } static int connection_fatally_broken(int error)