bzr commit into mysql-5.0-bugteam branch (v.narayanan:2780) Bug#43572

[V Narayanan]

#At file:///home/narayanan/Work/mysql_checkouts/shared_repository_directory/mysql-5.0-bugteam-43572-1/ based on revid:staale.smedseng@stripped

 2780 V Narayanan	2009-06-19
      Bug#43572 Handle failures from hash_init
            
      Failure to allocate memory for the hash->array element,
      caused hash_init to return without initializing the other
      members of the hash. Thus although the dynamic array
      buffer may be allocated at a later point in the code, the
      incompletely initialized hash caused fatal failures.
      
      This patch moves the initialization of the other members
      of the hash above the array allocation, so that the usage
      of this hash will not result in fatal failures.
     @ include/hash.h
        Bug#43572 Handle failures from hash_init
        
        hash_inited is used to verify that the hash is
        valid. After the change induced by the current
        patch hash->array.buffer !=0 is not a valid check
        for this condition, since, the dynamic array can
        be allocated even at a later time. Bootstrap SQL
        script is setting some variables, which are
        actually not set due to this hash_inited issue.
        Thus we get empty grant tables.
        
        A better way to check if the hash is valid is
        to verify that hash->blength is greater than 0.
     @ mysys/hash.c
        Bug#43572 Handle failures from hash_init
        
        Move the initialization of the other members
        of the hash above the array allocation, so that
        the usage of this hash will not result in fatal
        failures.

    modified:
      include/hash.h
      mysys/hash.c
=== modified file 'include/hash.h'
--- a/include/hash.h	2006-12-23 19:17:15 +0000
+++ b/include/hash.h	2009-06-19 11:59:21 +0000
@@ -63,7 +63,7 @@ void hash_replace(HASH *hash, HASH_SEARC
 my_bool hash_check(HASH *hash);			/* Only in debug library */
 
 #define hash_clear(H) bzero((char*) (H),sizeof(*(H)))
-#define hash_inited(H) ((H)->array.buffer != 0)
+#define hash_inited(H) ((H)->blength != 0)
 #define hash_init_opt(A,B,C,D,E,F,G,H) \
           (!hash_inited(A) && _hash_init(A,B,C,D,E,F,G, H CALLER_INFO))
 

=== modified file 'mysys/hash.c'
--- a/mysys/hash.c	2007-07-05 06:45:58 +0000
+++ b/mysys/hash.c	2009-06-19 11:59:21 +0000
@@ -45,6 +45,32 @@ static uint calc_hash(const HASH *hash, 
   return nr1;
 }
 
+/**
+  @brief Initialize the hash
+  
+  @details
+
+  Initialize the hash, by defining and giving valid values for
+  its elements. The failure to allocate memory for the
+  hash->array element will not result in a fatal failure. The
+  dynamic array that is part of the hash will allocate memory
+  as required during insertion.
+
+  @param[in,out] hash         The hash that is initialized
+  @param[in]     charset      The charater set information
+  @param[in]     size         The hash size
+  @param[in]     key_offest   The key offset for the hash
+  @param[in]     key_length   The length of the key used in
+                              the hash
+  @param[in]     get_key      get the key for the hash
+  @param[in]     free_element pointer to the function that
+                              does cleanup
+  @param[in]     CALLER_INFO_PROTO flag that define the behaviour 
+                                   of the hash
+  @return        inidicates success or failure of initialization
+    @retval 0 success
+    @retval 1 failure
+*/
 my_bool
 _hash_init(HASH *hash,CHARSET_INFO *charset,
 	   uint size,uint key_offset,uint key_length,
@@ -55,11 +81,6 @@ _hash_init(HASH *hash,CHARSET_INFO *char
   DBUG_PRINT("enter",("hash: 0x%lx  size: %d", (long) hash, size));
 
   hash->records=0;
-  if (my_init_dynamic_array_ci(&hash->array,sizeof(HASH_LINK),size,0))
-  {
-    hash->free=0;				/* Allow call to hash_free */
-    DBUG_RETURN(1);
-  }
   hash->key_offset=key_offset;
   hash->key_length=key_length;
   hash->blength=1;
@@ -67,7 +88,8 @@ _hash_init(HASH *hash,CHARSET_INFO *char
   hash->free=free_element;
   hash->flags=flags;
   hash->charset=charset;
-  DBUG_RETURN(0);
+  DBUG_RETURN(my_init_dynamic_array_ci(&hash->array, 
+                                       sizeof(HASH_LINK), size, 0));
 }
 
 
@@ -113,6 +135,7 @@ void hash_free(HASH *hash)
   hash_free_elements(hash);
   hash->free= 0;
   delete_dynamic(&hash->array);
+  hash->blength= 0;
   DBUG_VOID_RETURN;
 }
 


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