From patchwork Thu Jan 6 00:51:49 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Cai X-Patchwork-Id: 12704978 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 64ADFC433F5 for ; Thu, 6 Jan 2022 00:56:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344256AbiAFAz6 (ORCPT ); Wed, 5 Jan 2022 19:55:58 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44262 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344357AbiAFAzA (ORCPT ); Wed, 5 Jan 2022 19:55:00 -0500 Received: from mail-wr1-x433.google.com (mail-wr1-x433.google.com [IPv6:2a00:1450:4864:20::433]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8CCC6C0258D6 for ; Wed, 5 Jan 2022 16:51:52 -0800 (PST) Received: by mail-wr1-x433.google.com with SMTP id h23so1630425wrc.1 for ; Wed, 05 Jan 2022 16:51:52 -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=Si0p7y8fu/rgK8v1Spchti2bVOdv/+SnmdJchn+tx+c=; b=gBIhKvaE77ZWzmML/DiwYSCVfwuH31IOn+iG44PVTisAUaju42N8dcULWm8DdVU2UF Wgvj0R72Y9JXVE3j3ZFYa90Ox7rqGpa1OmJmYXOeEkaMhBwC3sEm4DDTLqynaKGzhLaM hdYCJ542KhWQfTjhn+6FWEE1TxiaE79Ca9FDWYtFZvrKQdLxmBaRRNGjpCsIf94qwyPF Z6MKhEx8bx7TSGcHfj4Hz1zAuwFfa0GbTLPVx9BfcRPk6gCxsvIcGga4yJAcyEb4x0aN gUz6wcw0Rs9mPvmpo0/HDGcBQ2JYwgrmK+UuflcwVyQU4k223wT3awLmhFrGAjDyuWKd M85A== 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=Si0p7y8fu/rgK8v1Spchti2bVOdv/+SnmdJchn+tx+c=; b=iHwoIrGwh3OU+HsvzJBP9zS5vLUhUB8laDB76A/yoVTGFVR/a3A6vYUS0CpX6I8G1U Qvzvp/z/a7l9utlPwLWGD1q+ZKx5Ie6OIJp0Gr+XAGgyxKvbxKKC8XCHYgXBsVrRamHu QYROPEkosOBjRbL6wHSIWt/kPyTji9lI1BWZpwF+gIMFpxxAOPID8bXb0QkFT4K66C1s /MQeilHcTYmp9Hh5EcWDOWdg6udJPN6A2++SNvRE0TU8lt0PAEoWUsSVdVtitpNkf+qF UOFmPwx+ldWSgzlk+88xekYDnmv/HuN6YpdXnSZws0JjVJDZdhrTIHr48KrAedBpevHy lSvg== X-Gm-Message-State: AOAM530xfkgtYcwYDo2OmEA8phoDvW/s8KGmFh9Q260HMcm1mMPuUJ33 qt2qbdy84xILOsMVg/myjH59fBQuMr4= X-Google-Smtp-Source: ABdhPJx6BRKDsR/cfwCZqqDLSS70iMealg9dvknmTGg6Sc0RVx3mymtkjeylGFoJobKJ0VFW0cRgyQ== X-Received: by 2002:a5d:4dca:: with SMTP id f10mr49285523wru.595.1641430311015; Wed, 05 Jan 2022 16:51:51 -0800 (PST) Received: from [127.0.0.1] ([13.74.141.28]) by smtp.gmail.com with ESMTPSA id d11sm540584wri.101.2022.01.05.16.51.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 05 Jan 2022 16:51:50 -0800 (PST) Message-Id: In-Reply-To: References: Date: Thu, 06 Jan 2022 00:51:49 +0000 Subject: [PATCH v5] 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-v5 Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-1125/john-cai/jc/replace-find-header-v5 Pull-Request: https://github.com/git/git/pull/1125 Range-diff vs v4: 1: a7b00022b00 ! 1: 02da3136c43 receive-pack.c: consolidate find header logic @@ commit.c: struct commit_list **commit_list_append(struct commit *commit, - while (line) { + /* -+ * NEEDSWORK: Between line[0] and msg[len], there may not be a LF nor NUL -+ * at all, and strchrnul() will scan beyond the range we were given -+ * Make this operation safer and abide by the contract to only read up to len. ++ * 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]. + */ + 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..f5224e65de2 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. + * Make this function safer by checking if the input is NUL-terminated + * or has a NL between line[0] and msg[len]. + */ + 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);