From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS53758 23.128.96.0/24 X-Spam-Status: No, score=-4.0 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RCVD_IN_DNSWL_LOW, SPF_HELO_PASS,SPF_PASS shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by dcvr.yhbt.net (Postfix) with ESMTP id C1DF71F8C6 for ; Mon, 2 Aug 2021 21:07:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231681AbhHBVHp (ORCPT ); Mon, 2 Aug 2021 17:07:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35826 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231583AbhHBVHp (ORCPT ); Mon, 2 Aug 2021 17:07:45 -0400 Received: from mail-wr1-x431.google.com (mail-wr1-x431.google.com [IPv6:2a00:1450:4864:20::431]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 150D5C06175F for ; Mon, 2 Aug 2021 14:07:34 -0700 (PDT) Received: by mail-wr1-x431.google.com with SMTP id z4so23001613wrv.11 for ; Mon, 02 Aug 2021 14:07:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=message-id:in-reply-to:references:from:date:subject:mime-version :content-transfer-encoding:fcc:to:cc; bh=CY7dZbCkTId0Nn1uoaiusprLnL9qcynN0l7hBBLxjUU=; b=L43q6k7pO/Ck5pUYPbGQqj4kFXWXFLW3b36oD6/dGs3r2SN0ouhlUouaeoD0UaRpiz Zu4UroyStQDWs9RuM/KbpYk4WFnch/Nt1ELalpjOLfO1Z7TPi2A8eaUDAb7vYP6yVP0Q CpUgVWUptMxXbkdIxMXZr+E39SWO+waKMQB/KTKTbgFuUZPJTPfDuW/zNh9yr9dI+2Dd CPBynyhgdnFYDFO+KbPl4zioQ8f1K8FNEWO3mM9F70YSj71ZHjHH/6ggA8ehEgkOfwn6 XIXJSl8SqnIyBXqNCFReT1H9dy7wLgbAIamRoRMF3QUR2Nsz/7jhe5hB22EQrLRx3ct4 iaPA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:message-id:in-reply-to:references:from:date :subject:mime-version:content-transfer-encoding:fcc:to:cc; bh=CY7dZbCkTId0Nn1uoaiusprLnL9qcynN0l7hBBLxjUU=; b=bm2lnVM6vzT7g/PGO5YPjWbiqEg3/9uhOgJMwP68UYBV8tqj/2mWZTMQbL907J9Jhp xE8mukl0ZeCKr6a33GEkKQUcSYXNMsxrEglBTvNV8OyrJ7EUmSDPmu7Gj9PQsGtsX48Q 7Xo2Bx4QdbdaVbY2BOwzQ03xoUa8YxMsHOUMcV+ri+/9jKhawbf16LlohXPF0HEf2uq7 Ue6LNkThvLcR0zZOK9K7I7TxAezlt6teAJK9U5gJZl6r+2ZXSCdyg8T/rQX3E/unLP1a 0J8cvn4OEAdkUF95xPFYVI2CqpfTgdB2B7BClyJY72mTm3wgydvRJMFnjt3G8xXvfo/U nfHw== X-Gm-Message-State: AOAM530G0AWCla+EN6IRK01zdQr9m2D1s4CpbyiG9aisjZtIx3xhvbam ZX93TQZFLLkg+Fg44t9E0wfwp5t/YDY= X-Google-Smtp-Source: ABdhPJzSQftX8WBzAajAsj4vI3+kJZoW8HAZn3c9G6PyQAkfItDHUT/mSahFtW9ZvXDFaGsHP1QDpA== X-Received: by 2002:adf:ef4d:: with SMTP id c13mr19529078wrp.281.1627938452685; Mon, 02 Aug 2021 14:07:32 -0700 (PDT) Received: from [127.0.0.1] ([13.74.141.28]) by smtp.gmail.com with ESMTPSA id e6sm8610126wme.6.2021.08.02.14.07.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 02 Aug 2021 14:07:32 -0700 (PDT) Message-Id: In-Reply-To: References: From: "Johannes Schindelin via GitGitGadget" Date: Mon, 02 Aug 2021 21:07:30 +0000 Subject: [PATCH v2] mingw: align symlinks-related rmdir() behavior with Linux MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Fcc: Sent To: git@vger.kernel.org Cc: Eric Sunshine , Johannes Schindelin , =?UTF-8?q?Thomas=20B=C3=A9tous?= Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org From: =?UTF-8?q?Thomas=20B=C3=A9tous?= When performing a rebase, rmdir() is called on the folder .git/logs. On Unix rmdir() exits without deleting anything in case .git/logs is a symbolic link but the equivalent functions on Windows (_rmdir, _wrmdir and RemoveDirectoryW) do not behave the same and remove the folder if it is symlinked even if it is not empty. This creates issues when folders in .git/ are symlinks which is especially the case when git-repo[1] is used: It replaces `.git/logs/` with a symlink. One such issue is that the _target_ of that symlink is removed e.g. during a `git rebase`, where `delete_reflog("REBASE_HEAD")` will not only try to remove `.git/logs/REBASE_HEAD` but then recursively try to remove the parent directories until an error occurs, a technique that obviously relies on `rmdir()` refusing to remove a symlink. This was reported in https://github.com/git-for-windows/git/issues/2967. This commit updates mingw_rmdir() so that its behavior is the same as Linux rmdir() in case of symbolic links. To verify that Git does not regress on the reported issue, this patch adds a regression test for the `git rebase` symptom, even if the same `rmdir()` behavior is quite likely to cause potential problems in other Git commands as well. [1]: git-repo is a python tool built on top of Git which helps manage many Git repositories. It stores all the .git/ folders in a central place by taking advantage of symbolic links. More information: https://gerrit.googlesource.com/git-repo/ Signed-off-by: Thomas Bétous Signed-off-by: Johannes Schindelin --- mingw: support the git-repo tool better This addresses an issue, originally reported at https://github.com/git-for-windows/git/issues/2967, where the git-repo tool [https://gerrit.googlesource.com/git-repo/] replaces folders in .git/ with symlinks and mingw_rmdir() erroneously removes the symlink target directory's contents. Changes since v1: * Fixed the authorship * Augmented the commit message to elaborate on what the issues are, concretely, with the current behavior of mingw_rmdir() * Added an explanation to the commit message as to what happens during a git rebase that would trigger the rmdir() code path to misbehave * Adjusted the code comment to talk specifically about the remove_path() caller and why we want to align with Linux' rmdir() behavior Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1008%2Fdscho%2Ffix-rmdir-with-symlinks-on-windows-v2 Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1008/dscho/fix-rmdir-with-symlinks-on-windows-v2 Pull-Request: https://github.com/gitgitgadget/git/pull/1008 Range-diff vs v1: 1: c5a7fe0007f ! 1: 0a9cb1bcc14 mingw: align symlinks-related rmdir() behavior with Linux @@ ## Metadata ## -Author: Johannes Schindelin +Author: Thomas Bétous ## Commit message ## mingw: align symlinks-related rmdir() behavior with Linux @@ Commit message is symlinked even if it is not empty. This creates issues when folders in .git/ are symlinks which is - especially the case when git-repo[1] is used. + especially the case when git-repo[1] is used: It replaces `.git/logs/` + with a symlink. + + One such issue is that the _target_ of that symlink is removed e.g. + during a `git rebase`, where `delete_reflog("REBASE_HEAD")` will not + only try to remove `.git/logs/REBASE_HEAD` but then recursively try to + remove the parent directories until an error occurs, a technique that + obviously relies on `rmdir()` refusing to remove a symlink. + + This was reported in https://github.com/git-for-windows/git/issues/2967. This commit updates mingw_rmdir() so that its behavior is the same as Linux rmdir() in case of symbolic links. - This fixes https://github.com/git-for-windows/git/issues/2967 + To verify that Git does not regress on the reported issue, this patch + adds a regression test for the `git rebase` symptom, even if the same + `rmdir()` behavior is quite likely to cause potential problems in other + Git commands as well. [1]: git-repo is a python tool built on top of Git which helps manage many Git repositories. It stores all the .git/ folders in a central @@ compat/mingw.c: int mingw_rmdir(const char *pathname) + struct stat st; + + /* -+ * Contrary to Linux rmdir(), Windows' _wrmdir() and _rmdir() -+ * will remove the directory at the path if it is a symbolic link -+ * which leads to issues when symlinks are used in the .git folder -+ * (in the context of git-repo for instance). So before calling _wrmdir() -+ * we first check if the path is a symbolic link. If it is, we exit -+ * and return the same error as Linux rmdir() in this case (ENOTDIR). -+ */ ++ * Contrary to Linux' `rmdir()`, Windows' _wrmdir() and _rmdir() ++ * (and `RemoveDirectoryW()`) will attempt to remove the target of a ++ * symbolic link (if it points to a directory). ++ * ++ * This behavior breaks the assumption of e.g. `remove_path()` which ++ * upon successful deletion of a file will attempt to remove its parent ++ * directories recursively until failure (which usually happens when ++ * the directory is not empty). ++ * ++ * Therefore, before calling `_wrmdir()`, we first check if the path is ++ * a symbolic link. If it is, we exit and return the same error as ++ * Linux' `rmdir()` would, i.e. `ENOTDIR`. ++ */ + if (!mingw_lstat(pathname, &st) && S_ISLNK(st.st_mode)) { + errno = ENOTDIR; + return -1; compat/mingw.c | 21 +++++++++++++++++++++ t/t3400-rebase.sh | 10 ++++++++++ t/test-lib.sh | 6 ++++++ 3 files changed, 37 insertions(+) diff --git a/compat/mingw.c b/compat/mingw.c index aa647b367b0..9e0cd1e097f 100644 --- a/compat/mingw.c +++ b/compat/mingw.c @@ -341,6 +341,27 @@ int mingw_rmdir(const char *pathname) { int ret, tries = 0; wchar_t wpathname[MAX_PATH]; + struct stat st; + + /* + * Contrary to Linux' `rmdir()`, Windows' _wrmdir() and _rmdir() + * (and `RemoveDirectoryW()`) will attempt to remove the target of a + * symbolic link (if it points to a directory). + * + * This behavior breaks the assumption of e.g. `remove_path()` which + * upon successful deletion of a file will attempt to remove its parent + * directories recursively until failure (which usually happens when + * the directory is not empty). + * + * Therefore, before calling `_wrmdir()`, we first check if the path is + * a symbolic link. If it is, we exit and return the same error as + * Linux' `rmdir()` would, i.e. `ENOTDIR`. + */ + if (!mingw_lstat(pathname, &st) && S_ISLNK(st.st_mode)) { + errno = ENOTDIR; + return -1; + } + if (xutftowcs_path(wpathname, pathname) < 0) return -1; diff --git a/t/t3400-rebase.sh b/t/t3400-rebase.sh index 0bb88aa982b..23dbd3c82ed 100755 --- a/t/t3400-rebase.sh +++ b/t/t3400-rebase.sh @@ -406,4 +406,14 @@ test_expect_success 'refuse to switch to branch checked out elsewhere' ' test_i18ngrep "already checked out" err ' +test_expect_success MINGW,SYMLINKS_WINDOWS 'rebase when .git/logs is a symlink' ' + git checkout main && + mv .git/logs actual_logs && + cmd //c "mklink /D .git\logs ..\actual_logs" && + git rebase -f HEAD^ && + test -L .git/logs && + rm .git/logs && + mv actual_logs .git/logs +' + test_done diff --git a/t/test-lib.sh b/t/test-lib.sh index adaf03543e8..73f6d645b66 100644 --- a/t/test-lib.sh +++ b/t/test-lib.sh @@ -1513,6 +1513,12 @@ test_lazy_prereq SYMLINKS ' ln -s x y && test -h y ' +test_lazy_prereq SYMLINKS_WINDOWS ' + # test whether symbolic links are enabled on Windows + test_have_prereq MINGW && + cmd //c "mklink y x" &> /dev/null && test -h y +' + test_lazy_prereq FILEMODE ' test "$(git config --bool core.filemode)" = true ' base-commit: ebf3c04b262aa27fbb97f8a0156c2347fecafafb -- gitgitgadget