[tarantool-patches] Re: [PATCH v1 1/1] xlog: fix out of static memory on metadata load

  • From: Vladimir Davydov <vdavydov.dev@xxxxxxxxx>
  • To: Kirill Shcherbatov <kshcherbatov@xxxxxxxxxxxxx>
  • Date: Fri, 17 Aug 2018 15:46:41 +0300

On Fri, Aug 17, 2018 at 03:39:50PM +0300, Kirill Shcherbatov wrote:

Too much of code duplication. Please add a helper for key matching.
Hi! ok.

===========================================

 src/box/xlog.c | 23 ++++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/src/box/xlog.c b/src/box/xlog.c
index 5ed11fc..c870d9d 100644
--- a/src/box/xlog.c
+++ b/src/box/xlog.c
@@ -183,6 +183,13 @@ parse_vclock(const char *val, const char *val_end, 
struct vclock *vclock)
      return 0;
 }
 
+static inline bool
+xlog_meta_key_cmp(const char *key, uint32_t key_len, const char *str,
+               uint32_t str_len)

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.

+{
+     return key_len != str_len || memcmp(key, str, key_len);
+}
+
 /**
  * Parse xlog meta from buffer, update buffer read
  * position in case of success
@@ -261,8 +268,11 @@ 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) {
+             size_t len = key_end - key;
+             if (xlog_meta_key_cmp(key, len, INSTANCE_UUID_KEY,
+                                   strlen(INSTANCE_UUID_KEY)) == 0 ||
+                 xlog_meta_key_cmp(key, len, INSTANCE_UUID_KEY_V12,
+                                       strlen(INSTANCE_UUID_KEY_V12)) == 0) {
                      /*
                       * Instance: <uuid>
                       */
@@ -277,19 +287,22 @@ 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_cmp(key, len, VCLOCK_KEY,
+                                          strlen(VCLOCK_KEY)) == 0) {
                      /*
                       * 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_cmp(key, len, PREV_VCLOCK_KEY,
+                                          strlen(PREV_VCLOCK_KEY)) == 0) {
                      /*
                       * 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_cmp(key, len, VERSION_KEY,
+                                          strlen(VERSION_KEY)) == 0) {
                      /* Ignore Version: for now */
              } else {
                      /*

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