Re: [HACKERS] Preventing some SQL commands

[Thomas Hallgren]

James William Pye
bool (*SPI_UtilityFilter) (NodeTag aStmt);
To a "void SPI_FilterUtilities(void *execPlan, SPI_UtilityFilter fp)".
Throwing an error if deemed necessary by the pointed to function.
 

After browsing the code a bit more, I realize that the above suggestion 
is superior to my own. It doesn't require a memory allocation and it's 
very close to what I'd like to have. I'd like it a bit more generic to 
allow arbitrary perusal of Query attributes. Like this to be more precise:

typedef bool (*QueryVisitor)(Query* query, void *clientData);
bool
SPI_traverse_query_roots(void *plan, QueryVisitor queryVisitor, void* 
clientData)
{
   List     *query_list_list = ((_SPI_plan*)plan)->qtlist;
   ListCell *query_list_list_item;

   foreach(query_list_list_item, query_list_list)
   {
       List     *query_list = lfirst(query_list_list_item);
       ListCell *query_list_item;
       foreach(query_list_item, query_list)
       {
           if(!queryVisitor((Query *)lfirst(query_list_item), clientData))
               return false;
       }
   }
   return true;
}
This will allow me to implement a QueryVisitor like so:
static bool detectTransactCommands(Query* query, void* clientData)
{
   return !(query->commandType == CMD_UTILITY &&
           IsA(query->utilityStmt, TransactionStmt));
}
and then test using:
if(!SPI_traverse_query_roots(myPlan, detectTransactCommands, null))
   /* Handle error here */
Any chance a patch containing the SPI_traverse_query_roots would be 
accepted?

Regards,
Thomas Hallgren

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