> There have been some recent changes to try to address this
> by placing various limits on number of columns, length of
> SQL expressions, length of SQL statements etc. See:
>
> http://www.sqlite.org/cvstrac/fileview?f=sqlite/src/limits.h&v=1.6
Nice. Limit is much better than a crash. But I hope that I will always remain
configurable and will be possible to specify really large values.
> But so that we can check, can you post the database schema
> and the actual SQL statement that caused the crash in the
> sqlite shell? Or mail it to me off-list if it's too large or
> something.
Below is a simple C programme that causes a crash with default stack size
(tested with MSVC i cygwin's gcc):
#include <stdio.h>
#include <string.h>
#include <malloc.h>
#include "sqlite3.h"
int main(int argc, char **argv){
sqlite3 *db;
char *str = (char *) malloc(1000000);
int rc, i;
strcpy(str, "select * from (select 1");
for (i = 0; i < 5000; ++i) {
strcat(str, " union select 1");
}
strcat(str, ")");
rc = sqlite3_open("test.db3", &db);
printf("rc: %d\n", rc);
rc = sqlite3_exec(db, str, NULL, 0, NULL);
printf("rc: %d\n", rc);
rc = sqlite3_close(db);
printf("rc: %d\n", rc);
return 0;
}
If you still want the big query let me know, but it basically does the same -
it doesn't even need any table.
I was thinking about sqlite based solution (other solutions are: don't make
such query or increase stack limit). I guess the best way is:
-include multiSelect in sqlite3Select - that's the easy part
-instead of recursive calls to sqlite3Select use gotos with self written
stack created on the heap - unfortunatelly it requires to keep track of all
created variables. They are mostly in front of the function but still it's
annoying to have to remember all of them.
Using MSVC it's easy prevent a crash: __try, __except and _resetstkoflw.
I have no idea yet hot to do this with gcc. Signal can be caught, but I
wasn't able to do anything more with demaged stack. I was looking at
-fstack-check - it does print information but i dont know how to catch the
error ant recover.
----------------------------------------------------------------------
Kasia Cichopek eksponuje biust
>>> http://link.interia.pl/f1a6f
-----------------------------------------------------------------------------
To unsubscribe, send email to [EMAIL PROTECTED]
-----------------------------------------------------------------------------
