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 X-Spam-Level: X-Spam-Status: No, score=-12.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 13E69C07E9B for ; Wed, 7 Jul 2021 19:07:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EE63C61CCC for ; Wed, 7 Jul 2021 19:07:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231240AbhGGTKh (ORCPT ); Wed, 7 Jul 2021 15:10:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47246 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231193AbhGGTKf (ORCPT ); Wed, 7 Jul 2021 15:10:35 -0400 Received: from mail-wr1-x434.google.com (mail-wr1-x434.google.com [IPv6:2a00:1450:4864:20::434]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0EF7BC06175F for ; Wed, 7 Jul 2021 12:07:54 -0700 (PDT) Received: by mail-wr1-x434.google.com with SMTP id a13so4263160wrf.10 for ; Wed, 07 Jul 2021 12:07:53 -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=bvUW0G4+ZOHhTiiIC/e71UTDkt5bfv+FBm5/WfeqzH4=; b=WXIAoggDgc7yKlqZC2XzRzSWCH/Z6+bkMaOsan91NUy48hJXJMI2jZ9OxkWgBfym9G ezBaDCwjUTOW4UXZwIxc0b7zQycIKGy9u+zhjKvrFEseFZAG7bvC9lIDp+zy6IWTt5Vb 5nqQOmjV9VOa+2Kt4jROKnykIbJv5t8RavxNcCBXtlcnCWul9C6Vs9aUTvNGgCA9fVT4 fphoQtLi8DsjsS7sUgpQdpJftMbUI1g1nY6pybfygQz3M0LrnGTjPimVpNIAY6zoFpuJ Bc6O+pXGT8HeO9OMblMvR6PFtFVqtZmJ1tl5rzz1+8zuYZ4pqZ2oFGAaeV2/rEOycYF7 yw2g== 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=bvUW0G4+ZOHhTiiIC/e71UTDkt5bfv+FBm5/WfeqzH4=; b=EK5gnNP6EvBjPLTWiJ3hrOuhN+QEcWrSF0l3NWd1lqqxuPD0rMU2cDZ5Ibw1BYxkk9 utPaSoL3XCtPuSehg0eNckw9NmkcRwkP43+6yyz945M1CozBRTmkFMi23jOqkwAufG2c XJJV41EuZdGBpkht/J6yGt2RSYuJieCXmJp7ryHda/rG8UhJ1dP/4SzXR+GsTJrNVLs0 fprFiV4rGrF37OIhcopMAvN7dzgZFR/0S8fpB8zG1SakyRcGnL7qmLAuYmXN9hWoh5M+ A0XhnGxzQ7KhrwbV4xEk6yhLbPETnGgoRxRkcve8nVq3OtWID21XdHRZVbKakr5v9fUp sggQ== X-Gm-Message-State: AOAM531AXYiK7TevtyNT6tjk+mGw7CzfLQ3YKAkOaYZkRQMxb1VlQ47Y DMqgoXxl6n24fi8Mmuq7vHSt9JFRr4Q= X-Google-Smtp-Source: ABdhPJyqYjgbxEM2DSJ+D5T8K6MM3EuCkR9jzm0wcjjfNLGGWU/MtrqWsP6BDE5qRXlFcEoEVXMWVg== X-Received: by 2002:a5d:4d4b:: with SMTP id a11mr5631747wru.325.1625684872589; Wed, 07 Jul 2021 12:07:52 -0700 (PDT) Received: from [127.0.0.1] ([13.74.141.28]) by smtp.gmail.com with ESMTPSA id c9sm14394350wrx.22.2021.07.07.12.07.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 07 Jul 2021 12:07:52 -0700 (PDT) Message-Id: <95025080c16f535599826ed4f013845d712b0e8d.1625684869.git.gitgitgadget@gmail.com> In-Reply-To: References: From: "Han-Wen Nienhuys via GitGitGadget" Date: Wed, 07 Jul 2021 19:07:45 +0000 Subject: [PATCH v5 2/6] refs/files-backend: stop setting errno from lock_ref_oid_basic MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Fcc: Sent To: git@vger.kernel.org Cc: Han-Wen Nienhuys , Jonathan Tan , =?UTF-8?Q?=C3=86var_Arnfj=C3=B6r=C3=B0?= Bjarmason , Han-Wen Nienhuys , Han-Wen Nienhuys Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org From: Han-Wen Nienhuys refs/files-backend.c::lock_ref_oid_basic() tries to signal how it failed to its callers using errno. It is safe to stop setting errno here, because the callers of this file-scope static function are * files_copy_or_rename_ref() * files_create_symref() * files_reflog_expire() None of them looks at errno after seeing a negative return from lock_ref_oid_basic() to make any decision, and no caller of these three functions looks at errno after they signal a failure by returning a negative value. In particular, * files_copy_or_rename_ref() - here, calls are followed by error() (which performs I/O) or write_ref_to_lockfile() (which calls parse_object() which may perform I/O) * files_create_symref() - here, calls are followed by error() or create_symref_locked() (which performs I/O and does not inspect errno) * files_reflog_expire() - here, calls are followed by error() or refs_reflog_exists() (which calls a function in a vtable that is not documented to use and/or preserve errno) Signed-off-by: Han-Wen Nienhuys Reviewed-by: Ævar Arnfjörð Bjarmason --- refs/files-backend.c | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-) diff --git a/refs/files-backend.c b/refs/files-backend.c index 677b7e4cdd2..83ddfb3b627 100644 --- a/refs/files-backend.c +++ b/refs/files-backend.c @@ -910,7 +910,6 @@ static int create_reflock(const char *path, void *cb) /* * Locks a ref returning the lock on success and NULL on failure. - * On failure errno is set to something meaningful. */ static struct ref_lock *lock_ref_oid_basic(struct files_ref_store *refs, const char *refname, @@ -922,7 +921,6 @@ static struct ref_lock *lock_ref_oid_basic(struct files_ref_store *refs, { struct strbuf ref_file = STRBUF_INIT; struct ref_lock *lock; - int last_errno = 0; int mustexist = (old_oid && !is_null_oid(old_oid)); int resolve_flags = RESOLVE_REF_NO_RECURSE; int resolved; @@ -949,7 +947,6 @@ static struct ref_lock *lock_ref_oid_basic(struct files_ref_store *refs, * to remain. */ if (remove_empty_directories(&ref_file)) { - last_errno = errno; if (!refs_verify_refname_available( &refs->base, refname, extras, skip, err)) @@ -962,10 +959,13 @@ static struct ref_lock *lock_ref_oid_basic(struct files_ref_store *refs, &lock->old_oid, type); } if (!resolved) { - last_errno = errno; + int last_errno = errno; if (last_errno != ENOTDIR || - !refs_verify_refname_available(&refs->base, refname, - extras, skip, err)) + /* in case of D/F conflict, try to generate a better error + * message. If that fails, fall back to strerror(ENOTDIR). + */ + !refs_verify_refname_available(&refs->base, refname, extras, + skip, err)) strbuf_addf(err, "unable to resolve reference '%s': %s", refname, strerror(last_errno)); @@ -981,20 +981,17 @@ static struct ref_lock *lock_ref_oid_basic(struct files_ref_store *refs, if (is_null_oid(&lock->old_oid) && refs_verify_refname_available(refs->packed_ref_store, refname, extras, skip, err)) { - last_errno = ENOTDIR; goto error_return; } lock->ref_name = xstrdup(refname); if (raceproof_create_file(ref_file.buf, create_reflock, &lock->lk)) { - last_errno = errno; unable_to_lock_message(ref_file.buf, errno, err); goto error_return; } if (verify_lock(&refs->base, lock, old_oid, mustexist, err)) { - last_errno = errno; goto error_return; } goto out; @@ -1005,7 +1002,6 @@ static struct ref_lock *lock_ref_oid_basic(struct files_ref_store *refs, out: strbuf_release(&ref_file); - errno = last_errno; return lock; } -- gitgitgadget