From patchwork Mon Sep 10 17:05:22 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Linus Arver via GitGitGadget X-Patchwork-Id: 10594545 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8C36115E2 for ; Mon, 10 Sep 2018 17:05:26 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 75A9928E96 for ; Mon, 10 Sep 2018 17:05:26 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 69D2728D9E; Mon, 10 Sep 2018 17:05:26 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id F16FD28D9E for ; Mon, 10 Sep 2018 17:05:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728856AbeIJWA0 (ORCPT ); Mon, 10 Sep 2018 18:00:26 -0400 Received: from mail-pl1-f196.google.com ([209.85.214.196]:46775 "EHLO mail-pl1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726603AbeIJWAZ (ORCPT ); Mon, 10 Sep 2018 18:00:25 -0400 Received: by mail-pl1-f196.google.com with SMTP id t19-v6so10019476ply.13 for ; Mon, 10 Sep 2018 10:05:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:message-id:in-reply-to:references:from:subject:fcc :content-transfer-encoding:mime-version:to:cc; bh=uaaCPyujHx/G847/ERRvieUkKT3T50xow363oBxFmpc=; b=eC20yPSL2jcvyVyTkm9Hyk3kQnIzacRAWd0yRMlr+OoVjOfngxXkX7GZPBNntY2brj glTMpTaBFOlwK9VMf1rzm3layBJoGEwvvdDybOtLTmOAZengcMh5ciyXYyOg+1ZKLyVo 2Y1Mg23qL+Gjl3ex0FU3+r+3UVGLtu+9o+I/3swRI/adXFL8Dnv8EHpnYEALFY6dFZjM iWsEbvjrBCwukoTWHt5kTONdaQ4k7Gk574YuRmzAEgdFd43XXuHWEG6Io9OpXVM01b0X AWgCTEpP1r8kK0KpHr/1g0ca21tHHapgkqnxZ20xlgXXd7LuZn7NQpPWn2TN4pnsifZZ uVmw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:message-id:in-reply-to:references:from :subject:fcc:content-transfer-encoding:mime-version:to:cc; bh=uaaCPyujHx/G847/ERRvieUkKT3T50xow363oBxFmpc=; b=cGk6vMRJA0WNS5jLnaX4JN7dmv/ubDitzys3ii5dF43O+ufYtDYJG3dOdGXrfXQUD+ MSHB1lpoO7SpgIRr3XFy5GdnFkQVhfE4N/XZcLj/cbQYuppnGoAecN6QEXPuxASr2RrA Kefn4a5Ah2wuszFPko0Sz1r+0NBZw0QIiEQuO0y6gUzfExCgIv6M0vMAG1pNfVWMiNKP CNbXqm1QSY5vFchiLPuYzPXrXNTEG99YrO6t6WdMZ8mFl7dzRUMxeQ2xKpvaairMt5Gu pKj+9nIzy1QQY4TnylAGC6s9fjVz3Ahs5un5AiCQuRZyJ5TmEzCY0z+9nvomu/esCZkd JW0g== X-Gm-Message-State: APzg51CcOd1Pm3B5Xj60URzb2FLE4rOV8LGbcIx3BZiT2wAa3Ig5sDay DraL/4oJbS+Wb6sxDYICE7bOpS80 X-Google-Smtp-Source: ANB0VdZF8P+RY3xzK3qmxpgN0m58cYqLmeyktnF4uDPYdTOvIdsgjyj1oTquO4O+g5H/2orj0aiyvA== X-Received: by 2002:a17:902:aa83:: with SMTP id d3-v6mr22760973plr.242.1536599123718; Mon, 10 Sep 2018 10:05:23 -0700 (PDT) Received: from [127.0.0.1] ([40.112.142.204]) by smtp.gmail.com with ESMTPSA id h85-v6sm31439536pfk.71.2018.09.10.10.05.22 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 10 Sep 2018 10:05:22 -0700 (PDT) Date: Mon, 10 Sep 2018 10:05:22 -0700 (PDT) X-Google-Original-Date: Mon, 10 Sep 2018 17:05:17 GMT Message-Id: In-Reply-To: References: From: "Jeff Hostetler via GitGitGadget" Subject: [PATCH v2 2/2] mingw: fix mingw_open_append to work with named pipes Fcc: Sent MIME-Version: 1.0 To: git@vger.kernel.org Cc: jeffhost@microsoft.com, Junio C Hamano , Jeff Hostetler Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Jeff Hostetler Signed-off-by: Jeff Hostetler --- compat/mingw.c | 38 ++++++++++++++++++++++++++++++++--- t/t0051-windows-named-pipe.sh | 2 +- 2 files changed, 36 insertions(+), 4 deletions(-) diff --git a/compat/mingw.c b/compat/mingw.c index 858ca14a57..f87376b26a 100644 --- a/compat/mingw.c +++ b/compat/mingw.c @@ -341,6 +341,19 @@ int mingw_mkdir(const char *path, int mode) return ret; } +/* + * Calling CreateFile() using FILE_APPEND_DATA and without FILE_WRITE_DATA + * is documented in [1] as opening a writable file handle in append mode. + * (It is believed that) this is atomic since it is maintained by the + * kernel unlike the O_APPEND flag which is racily maintained by the CRT. + * + * [1] https://docs.microsoft.com/en-us/windows/desktop/fileio/file-access-rights-constants + * + * This trick does not appear to work for named pipes. Instead it creates + * a named pipe client handle that cannot be written to. Callers should + * just use the regular _wopen() for them. (And since client handle gets + * bound to a unique server handle, it isn't really an issue.) + */ static int mingw_open_append(wchar_t const *wfilename, int oflags, ...) { HANDLE handle; @@ -360,10 +373,12 @@ static int mingw_open_append(wchar_t const *wfilename, int oflags, ...) NULL, create, FILE_ATTRIBUTE_NORMAL, NULL); if (handle == INVALID_HANDLE_VALUE) return errno = err_win_to_posix(GetLastError()), -1; + /* * No O_APPEND here, because the CRT uses it only to reset the - * file pointer to EOF on write(); but that is not necessary - * for a file created with FILE_APPEND_DATA. + * file pointer to EOF before each write(); but that is not + * necessary (and may lead to races) for a file created with + * FILE_APPEND_DATA. */ fd = _open_osfhandle((intptr_t)handle, O_BINARY); if (fd < 0) @@ -371,6 +386,23 @@ static int mingw_open_append(wchar_t const *wfilename, int oflags, ...) return fd; } +#define IS_SBS(ch) (((ch) == '/') || ((ch) == '\\')) +/* + * Does the pathname map to the local named pipe filesystem? + * That is, does it have a "//./pipe/" prefix? + */ +static int mingw_is_local_named_pipe_path(const char *filename) +{ + return (IS_SBS(filename[0]) && + IS_SBS(filename[1]) && + filename[2] == '.' && + IS_SBS(filename[3]) && + !strncasecmp(filename+4, "pipe", 4) && + IS_SBS(filename[8]) && + filename[9]); +} +#undef IS_SBS + int mingw_open (const char *filename, int oflags, ...) { typedef int (*open_fn_t)(wchar_t const *wfilename, int oflags, ...); @@ -387,7 +419,7 @@ int mingw_open (const char *filename, int oflags, ...) if (filename && !strcmp(filename, "/dev/null")) filename = "nul"; - if (oflags & O_APPEND) + if ((oflags & O_APPEND) && !mingw_is_local_named_pipe_path(filename)) open_fn = mingw_open_append; else open_fn = _wopen; diff --git a/t/t0051-windows-named-pipe.sh b/t/t0051-windows-named-pipe.sh index e3c36341a0..10ac92d225 100755 --- a/t/t0051-windows-named-pipe.sh +++ b/t/t0051-windows-named-pipe.sh @@ -4,7 +4,7 @@ test_description='Windows named pipes' . ./test-lib.sh -test_expect_failure MINGW 'o_append write to named pipe' ' +test_expect_success MINGW 'o_append write to named pipe' ' GIT_TRACE="$(pwd)/expect" git status >/dev/null 2>&1 && { test-tool windows-named-pipe t0051 >actual 2>&1 & } && pid=$! &&