From patchwork Thu Jan 6 20:07:35 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Cai X-Patchwork-Id: 12705689 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7A237C433EF for ; Thu, 6 Jan 2022 20:07:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232454AbiAFUHk (ORCPT ); Thu, 6 Jan 2022 15:07:40 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49754 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231401AbiAFUHj (ORCPT ); Thu, 6 Jan 2022 15:07:39 -0500 Received: from mail-wr1-x42d.google.com (mail-wr1-x42d.google.com [IPv6:2a00:1450:4864:20::42d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 094B4C061245 for ; Thu, 6 Jan 2022 12:07:39 -0800 (PST) Received: by mail-wr1-x42d.google.com with SMTP id o3so6947060wrh.10 for ; Thu, 06 Jan 2022 12:07:38 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=message-id:in-reply-to:references:from:date:subject:fcc :content-transfer-encoding:mime-version:to:cc; bh=g9MllGiuqVSZBMcgEGAmjva+Xs/HACThoEjaDvNbqO8=; b=UbVrk1neN0Fpw3NcEe1WrL9q7Uu1UmTgRxnNjwjbNSnIsd9DZcWcHFcubFZQXJwYSJ /iCWwpCMIJQaqjeCijJgM94o5CxvUDxZD2iidP6/21VrSKDpZI1t4ZcutylWsVfJAZ16 7Ia4tmVS09pY6vB91HPtbmUXA7n19wg4LsgzpMaiNokCByrqOw3zTD2K3L0sSyVwTwmK 5xj9UEOypnDncniiDq/M5+zrRgeRYr5zcLrjM/3f1CD8bcGXcSfmWyki5J4bykkTCRFT /KiBwWS9S5lRwtmYP0ibg7lsxKpqJQZfqIme2yw6+RCu173wbcxnNB0YaCJd76pckpEO QYKA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:in-reply-to:references:from:date :subject:fcc:content-transfer-encoding:mime-version:to:cc; bh=g9MllGiuqVSZBMcgEGAmjva+Xs/HACThoEjaDvNbqO8=; b=QNNney0OBRL6bQfH2vHxbeyg729mcDGsUxBWARlOBvOzLlcAM3VOBN/3VWTDinCwqk +PCxyqkq3DR7x1lFzFNfjJPWeRCrEoT+NNCIdFz6O325rpCXnmHzWNIWxsYH6DRWfWLw OZGkC0hHKi6IXR9Rn09wozIY95uIaEBbcjU1YSDAY+kkq37S7PesPcFKO0PthgUA19Ya 6ghU9xomw7DwkWdTLnPNBOGMhCWXKe5P6cSA1yKJW1FWhHlgxsE64fotZB7Mq5nso2mF GtsyD45jUmzjmGfDAL3JiLFAgVzBkKuUrWaU3rcPcRYcjtl8/Yt+xvl2B+oRY4dS8Rm9 oVNA== X-Gm-Message-State: AOAM531EdKyzwkp9ZOOvBs3zkndsxd99zbUdvF2a+sXib+BBL9zuFINQ r0rLfTO+I7VJcmWJPapXA/Wak1wF0VU= X-Google-Smtp-Source: ABdhPJwV6rx9p2WCOR8BW+ZRj5V5nMd+gNtoyZq1Q0g9mBHGtE4Uthu9ZF/yBNMIyOovStTeybI2jA== X-Received: by 2002:adf:f70b:: with SMTP id r11mr53750394wrp.496.1641499657387; Thu, 06 Jan 2022 12:07:37 -0800 (PST) Received: from [127.0.0.1] ([13.74.141.28]) by smtp.gmail.com with ESMTPSA id o10sm2719386wmq.31.2022.01.06.12.07.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 06 Jan 2022 12:07:36 -0800 (PST) Message-Id: In-Reply-To: References: Date: Thu, 06 Jan 2022 20:07:35 +0000 Subject: [PATCH v6] receive-pack.c: consolidate find header logic Fcc: Sent MIME-Version: 1.0 To: git@vger.kernel.org Cc: John Cai , John Cai Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org From: John Cai From: John Cai There are two functions that have very similar logic of finding a header value. find_commit_header, and find_header. We can conslidate the logic by introducing a new function find_header_mem, which is equivalent to find_commit_header except it takes a len parameter that determines how many bytes will be read. find_commit_header and find_header can then both call find_header_mem. This reduces duplicate logic, as the logic for finding header values can now all live in one place. Signed-off-by: John Cai --- Consolidate find_header logic into one function This addresses the NEEDSWORK comment in builtin/receive-pack.c: /** * NEEDSWORK: reuse find_commit_header() from jk/commit-author-parsing * after dropping "_commit" from its name and possibly moving it out * of commit.c **/ There are two functions that have very similar logic of finding a header value. find_commit_header, and find_header. We can conslidate the logic by introducing a new function find_header_mem, which is equivalent to find_commit_header except it takes a len parameter that determines how many bytes will be read. find_commit_header and find_header can then both call find_header_mem. This reduces duplicate logic, as the logic for finding header values can now all live in one place. Changes since v4: * adjust verbiage of NEEDSWORK comment block Changes since v3: * added NEEDSWORK block detailing what needs to be done to clean up find_header_mem * fixed verbiage in commit message * adjusted style of an if block (based on Junio's feedback) Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-1125%2Fjohn-cai%2Fjc%2Freplace-find-header-v6 Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-1125/john-cai/jc/replace-find-header-v6 Pull-Request: https://github.com/git/git/pull/1125 Range-diff vs v5: 1: 02da3136c43 ! 1: 2b01d92b951 receive-pack.c: consolidate find header logic @@ commit.c: struct commit_list **commit_list_append(struct commit *commit, + * NEEDSWORK: It's possible for strchrnul() to scan beyond the range + * given by len. However, current callers are safe because they compute + * len by scanning a NUL-terminated block of memory starting at msg. -+ * Make this function safer by checking if the input is NUL-terminated -+ * or has a NL between line[0] and msg[len]. ++ * Nonetheless, it would be better to ensure the function does not look ++ * at msg beyond the len provided by the caller. + */ + while (line && line < msg + len) { const char *eol = strchrnul(line, '\n'); builtin/receive-pack.c | 33 ++++++++++----------------------- commit.c | 16 ++++++++++++++-- commit.h | 5 +++++ 3 files changed, 29 insertions(+), 25 deletions(-) base-commit: c8b2ade48c204690119936ada89cd938c476c5c2 diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c index 9f4a0b816cf..5c2732a0d07 100644 --- a/builtin/receive-pack.c +++ b/builtin/receive-pack.c @@ -581,32 +581,19 @@ static char *prepare_push_cert_nonce(const char *path, timestamp_t stamp) return strbuf_detach(&buf, NULL); } -/* - * NEEDSWORK: reuse find_commit_header() from jk/commit-author-parsing - * after dropping "_commit" from its name and possibly moving it out - * of commit.c - */ static char *find_header(const char *msg, size_t len, const char *key, const char **next_line) { - int key_len = strlen(key); - const char *line = msg; - - while (line && line < msg + len) { - const char *eol = strchrnul(line, '\n'); - - if ((msg + len <= eol) || line == eol) - return NULL; - if (line + key_len < eol && - !memcmp(line, key, key_len) && line[key_len] == ' ') { - int offset = key_len + 1; - if (next_line) - *next_line = *eol ? eol + 1 : eol; - return xmemdupz(line + offset, (eol - line) - offset); - } - line = *eol ? eol + 1 : NULL; - } - return NULL; + size_t out_len; + const char *val = find_header_mem(msg, len, key, &out_len); + + if (!val) + return NULL; + + if (next_line) + *next_line = val + out_len + 1; + + return xmemdupz(val, out_len); } /* diff --git a/commit.c b/commit.c index a348f085b2b..28391c3468d 100644 --- a/commit.c +++ b/commit.c @@ -1631,12 +1631,20 @@ struct commit_list **commit_list_append(struct commit *commit, return &new_commit->next; } -const char *find_commit_header(const char *msg, const char *key, size_t *out_len) +const char *find_header_mem(const char *msg, size_t len, + const char *key, size_t *out_len) { int key_len = strlen(key); const char *line = msg; - while (line) { + /* + * NEEDSWORK: It's possible for strchrnul() to scan beyond the range + * given by len. However, current callers are safe because they compute + * len by scanning a NUL-terminated block of memory starting at msg. + * Nonetheless, it would be better to ensure the function does not look + * at msg beyond the len provided by the caller. + */ + while (line && line < msg + len) { const char *eol = strchrnul(line, '\n'); if (line == eol) @@ -1653,6 +1661,10 @@ const char *find_commit_header(const char *msg, const char *key, size_t *out_len return NULL; } +const char *find_commit_header(const char *msg, const char *key, size_t *out_len) +{ + return find_header_mem(msg, strlen(msg), key, out_len); +} /* * Inspect the given string and determine the true "end" of the log message, in * order to find where to put a new Signed-off-by trailer. Ignored are diff --git a/commit.h b/commit.h index 3ea32766bcb..38cc5426615 100644 --- a/commit.h +++ b/commit.h @@ -290,12 +290,17 @@ void free_commit_extra_headers(struct commit_extra_header *extra); /* * Search the commit object contents given by "msg" for the header "key". + * Reads up to "len" bytes of "msg". * Returns a pointer to the start of the header contents, or NULL. The length * of the header, up to the first newline, is returned via out_len. * * Note that some headers (like mergetag) may be multi-line. It is the caller's * responsibility to parse further in this case! */ +const char *find_header_mem(const char *msg, size_t len, + const char *key, + size_t *out_len); + const char *find_commit_header(const char *msg, const char *key, size_t *out_len);