Hi > But I wonder if it is safe that the old cursor_name is forgotten. old cursor_name is not assigned to other pointers, so it is safe that the old cursor_name is forgotten.
Best Regards! -----Original Message----- From: Matsumura, Ryo/松村 量 Sent: Monday, June 10, 2019 5:52 PM To: Zhang, Jie/张 杰 <zhangj...@cn.fujitsu.com>; pgsql-hackers@lists.postgresql.org Cc: Zhang, Jie/张 杰 <zhangj...@cn.fujitsu.com> Subject: RE: [PATCH] memory leak in ecpglib Hi On Mon. June. 10, 2019 at 09:54 AM Zhang, Jie < zhangj...@cn.fujitsu.com > wrote: > > Memory leaks occur when the ecpg_update_declare_statement() is called > the second time. Certainly it is. But I wonder if it is safe that the old cursor_name is forgotten. Regards Ryo Matsumura > -----Original Message----- > From: Zhang, Jie [mailto:zhangj...@cn.fujitsu.com] > Sent: Monday, June 10, 2019 9:54 AM > To: pgsql-hackers@lists.postgresql.org > Cc: Zhang, Jie/张 杰 <zhangj...@cn.fujitsu.com> > Subject: [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@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! > >
