From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <kshcherbatov@tarantool.org>
Subject: Re: [tarantool-patches] Re: [PATCH v1 1/1] xlog: fix out of static
 memory on metadata load
References: <217089583da1d608c61d1c4a106fee07d43332f9.1534336273.git.kshcherbatov@tarantool.org>
 <20180817101410.zomayvmosk5cp33j@esperanza>
 <7f51f275-0c09-103b-cb8a-207dc3f77420@tarantool.org>
 <20180817124641.xpd7tfewdeu6ksvx@esperanza>
From: Kirill Shcherbatov <kshcherbatov@tarantool.org>
Message-ID: <e35e48fd-9312-cbed-d8c7-cc4a6a0411bb@tarantool.org>
Date: Fri, 17 Aug 2018 17:46:49 +0300
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In-Reply-To: <20180817124641.xpd7tfewdeu6ksvx@esperanza>
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To: tarantool-patches@freelists.org, Vladimir Davydov <vdavydov.dev@gmail.com>
List-ID: <tarantool-patches.dev.tarantool.org>

> What's the point of passing str_len when you can compute it right in
> this function with strlen?
> 
> Also, please pass key_end instead of key_len to make function calls more
> compact.
> 
> Also, if the function returns bool (which is OK), you shouldn't check
> its return value against 0. And you'd better call it xlog_meta_key_match
> or xlog_meta_key_equal and make it return true on match and false
> otherwise.
> 
> Please fix.

diff --git a/src/box/xlog.c b/src/box/xlog.c
index 5ed11fc..ed6c06a 100644
--- a/src/box/xlog.c
+++ b/src/box/xlog.c
@@ -183,6 +183,12 @@ parse_vclock(const char *val, const char *val_end, struct vclock *vclock)
 	return 0;
 }
 
+static inline bool
+xlog_meta_key_equal(const char *key, uint32_t key_len, const char *str)
+{
+	return key_len == strlen(str) && memcmp(key, str, key_len) == 0;
+}
+
 /**
  * Parse xlog meta from buffer, update buffer read
  * position in case of success
@@ -261,8 +267,9 @@ xlog_meta_parse(struct xlog_meta *meta, const char **data,
 		assert(val <= val_end);
 		pos = eol + 1;
 
-		if (memcmp(key, INSTANCE_UUID_KEY, key_end - key) == 0 ||
-		    memcmp(key, INSTANCE_UUID_KEY_V12, key_end - key) == 0) {
+		uint32_t key_len = key_end - key;
+		if (xlog_meta_key_equal(key, key_len, INSTANCE_UUID_KEY) ||
+		    xlog_meta_key_equal(key, key_len, INSTANCE_UUID_KEY_V12)) {
 			/*
 			 * Instance: <uuid>
 			 */
@@ -277,19 +284,19 @@ xlog_meta_parse(struct xlog_meta *meta, const char **data,
 				diag_set(XlogError, "can't parse instance UUID");
 				return -1;
 			}
-		} else if (memcmp(key, VCLOCK_KEY, key_end - key) == 0){
+		} else if (xlog_meta_key_equal(key, key_len, VCLOCK_KEY)) {
 			/*
 			 * VClock: <vclock>
 			 */
 			if (parse_vclock(val, val_end, &meta->vclock) != 0)
 				return -1;
-		} else if (memcmp(key, PREV_VCLOCK_KEY, key_end - key) == 0) {
+		} else if (xlog_meta_key_equal(key, key_len, PREV_VCLOCK_KEY)) {
 			/*
 			 * PrevVClock: <vclock>
 			 */
 			if (parse_vclock(val, val_end, &meta->prev_vclock) != 0)
 				return -1;
-		} else if (memcmp(key, VERSION_KEY, key_end - key) == 0) {
+		} else if (xlog_meta_key_equal(key, key_len, VERSION_KEY)) {
 			/* Ignore Version: for now */
 		} else {
 			/*