[PATCH] memory leak in ecpglib

Hi all

Memory leaks occur when the ecpg_update_declare_statement() is called the second time.

FILE:postgresql\src\interfaces\ecpg\ecpglib\prepare.c
void
ecpg_update_declare_statement(const char *declared_name, const char *cursor_name, const int lineno)
{
struct declared_statement *p = NULL;

if (!declared_name || !cursor_name)
return;

/* Find the declared node by declared name */
p = ecpg_find_declared_statement(declared_name);
if (p)
p->cursor_name = ecpg_strdup(cursor_name, lineno); ★
}
ecpg_strdup() returns a pointer to a null-terminated byte string, which is a duplicate of the string pointed to by str.
The memory obtained is done dynamically using malloc and hence it can be freed using free().

When the ecpg_update_declare_statement() is called for the second time,
the memory allocated for p->cursor_name is not freed.

For example:

EXEC SQL BEGIN DECLARE SECTION;
char *selectString = "SELECT * FROM foo;";
int FooBar;
char DooDad[17];
EXEC SQL END DECLARE SECTION;

EXEC SQL CONNECT TO postgres(at)localhost:5432 AS con1 USER postgres;

EXEC SQL AT con1 DECLARE stmt_1 STATEMENT;
EXEC SQL AT con1 PREPARE stmt_1 FROM :selectString;

EXEC SQL AT con1 DECLARE cur_1 CURSOR FOR stmt_1; //★1 ECPGopen() --> ecpg_update_declare_statement()
EXEC SQL AT con1 OPEN cur_1;

EXEC SQL AT con1 DECLARE cur_2 CURSOR FOR stmt_1; //★2 ECPGopen() --> ecpg_update_declare_statement()
EXEC SQL AT con1 OPEN cur_2; Memory leaks

EXEC SQL FETCH cur_2 INTO:FooBar, :DooDad;
EXEC SQL COMMIT;
EXEC SQL DISCONNECT ALL;

We should free p->cursor_name before p->cursor_name = ecpg_strdup(cursor_name, lineno).
#############################################################################
if(p->cursor_name)
ecpg_free(p->cursor_name);
p->cursor_name = ecpg_strdup(cursor_name,lineno);
###########################################################################
Here is a patch.

Best Regards!