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kconfig: Don't leak symbol names during parsing

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Prior to this fix, zconf.y did not free symbol names from zconf.l in
these contexts:

	- After T_CONFIG ('config LEAKED')
	- After T_MENUCONFIG ('menuconfig LEAKED')
	- After T_SELECT ('select LEAKED')
	- After T_IMPLY ('imply LEAKED')
	- After T_DEFAULT in a choice ('default LEAKED')

All of these come in the form of T_WORD tokens, which always have their
associated string allocated on the heap in zconf.l and need to be freed.

Fix by introducing a new nonterminal 'nonconst_symbol' which takes a
T_WORD, fetches the symbol, and then frees the T_WORD string. The
already existing 'symbol' nonterminal works the same way but also
accepts T_WORD_QUOTE, corresponding to a constant symbol. T_WORD_QUOTE
should not be accepted in any of the contexts above, so the 'symbol'
nonterminal can't be reused here.

Fetching the symbol in 'nonconst_symbol' also removes a bunch of
sym_lookup() calls from actions.

Summary from Valgrind on 'menuconfig' (ARCH=x86) before the fix:

	LEAK SUMMARY:
	   definitely lost: 711,571 bytes in 37,756 blocks
	   ...

Summary after the fix:

	LEAK SUMMARY:
	   definitely lost: 387,504 bytes in 15,545 blocks
           ...

Signed-off-by: Ulf Magnusson <ulfalizer@gmail.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
This commit is contained in:
Ulf Magnusson 2017-10-08 19:11:18 +02:00 committed by Masahiro Yamada
parent 29c833061c
commit 26e47a3c11
1 changed files with 19 additions and 17 deletions
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36
scripts/kconfig/zconf.y
View File

@ -85,6 +85,7 @@ static struct menu *current_menu, *current_entry;
%nonassoc T_NOT
%type <string> prompt
%type <symbol> nonconst_symbol
%type <symbol> symbol
%type <expr> expr
%type <expr> if_expr
@ -145,12 +146,11 @@ option_error:
/* config/menuconfig entry */
config_entry_start: T_CONFIG T_WORD T_EOL
config_entry_start: T_CONFIG nonconst_symbol T_EOL
{
struct symbol *sym = sym_lookup($2, 0);
sym->flags |= SYMBOL_OPTIONAL;
menu_add_entry(sym);
printd(DEBUG_PARSE, "%s:%d:config %s\n", zconf_curname(), zconf_lineno(), $2);
$2->flags |= SYMBOL_OPTIONAL;
menu_add_entry($2);
printd(DEBUG_PARSE, "%s:%d:config %s\n", zconf_curname(), zconf_lineno(), $2->name);
};
config_stmt: config_entry_start config_option_list
@ -159,12 +159,11 @@ config_stmt: config_entry_start config_option_list
printd(DEBUG_PARSE, "%s:%d:endconfig\n", zconf_curname(), zconf_lineno());
};
menuconfig_entry_start: T_MENUCONFIG T_WORD T_EOL
menuconfig_entry_start: T_MENUCONFIG nonconst_symbol T_EOL
{
struct symbol *sym = sym_lookup($2, 0);
sym->flags |= SYMBOL_OPTIONAL;
menu_add_entry(sym);
printd(DEBUG_PARSE, "%s:%d:menuconfig %s\n", zconf_curname(), zconf_lineno(), $2);
$2->flags |= SYMBOL_OPTIONAL;
menu_add_entry($2);
printd(DEBUG_PARSE, "%s:%d:menuconfig %s\n", zconf_curname(), zconf_lineno(), $2->name);
};
menuconfig_stmt: menuconfig_entry_start config_option_list
@ -211,15 +210,15 @@ config_option: T_DEFAULT expr if_expr T_EOL
$1->stype);
};
config_option: T_SELECT T_WORD if_expr T_EOL
config_option: T_SELECT nonconst_symbol if_expr T_EOL
{
menu_add_symbol(P_SELECT, sym_lookup($2, 0), $3);
menu_add_symbol(P_SELECT, $2, $3);
printd(DEBUG_PARSE, "%s:%d:select\n", zconf_curname(), zconf_lineno());
};
config_option: T_IMPLY T_WORD if_expr T_EOL
config_option: T_IMPLY nonconst_symbol if_expr T_EOL
{
menu_add_symbol(P_IMPLY, sym_lookup($2, 0), $3);
menu_add_symbol(P_IMPLY, $2, $3);
printd(DEBUG_PARSE, "%s:%d:imply\n", zconf_curname(), zconf_lineno());
};
@ -308,10 +307,10 @@ choice_option: T_OPTIONAL T_EOL
printd(DEBUG_PARSE, "%s:%d:optional\n", zconf_curname(), zconf_lineno());
};
choice_option: T_DEFAULT T_WORD if_expr T_EOL
choice_option: T_DEFAULT nonconst_symbol if_expr T_EOL
{
if ($1->stype == S_UNKNOWN) {
menu_add_symbol(P_DEFAULT, sym_lookup($2, 0), $3);
menu_add_symbol(P_DEFAULT, $2, $3);
printd(DEBUG_PARSE, "%s:%d:default\n",
zconf_curname(), zconf_lineno());
} else
@ -491,7 +490,10 @@ expr: symbol { $$ = expr_alloc_symbol($1); }
| expr T_AND expr { $$ = expr_alloc_two(E_AND, $1, $3); }
;
symbol: T_WORD { $$ = sym_lookup($1, 0); free($1); }
/* For symbol definitions, selects, etc., where quotes are not accepted */
nonconst_symbol: T_WORD { $$ = sym_lookup($1, 0); free($1); };
symbol: nonconst_symbol
| T_WORD_QUOTE { $$ = sym_lookup($1, SYMBOL_CONST); free($1); }
;