From 8f452530e61b299d4d48f82f41ab5364723607ae Mon Sep 17 00:00:00 2001 From: Rickard Green Date: Wed, 5 Apr 2017 14:32:16 +0200 Subject: Stack guard for PCRE --- erts/emulator/beam/erl_bif_re.c | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) (limited to 'erts/emulator/beam/erl_bif_re.c') diff --git a/erts/emulator/beam/erl_bif_re.c b/erts/emulator/beam/erl_bif_re.c index ff7746ce1d..35b196743f 100644 --- a/erts/emulator/beam/erl_bif_re.c +++ b/erts/emulator/beam/erl_bif_re.c @@ -64,12 +64,47 @@ static void erts_erts_pcre_stack_free(void *ptr) { erts_free(ERTS_ALC_T_RE_STACK,ptr); } +#define ERTS_PCRE_STACK_MARGIN (10*1024) + +#ifdef ERTS_SMP +# define ERTS_STACK_LIMIT ((char *) ethr_get_stacklimit()) +#else +# define ERTS_STACK_LIMIT ((char *) erts_scheduler_stack_limit) +#endif + +static int +stack_guard_downwards(void) +{ + char *limit = ERTS_STACK_LIMIT; + char c; + + ASSERT(limit); + + return erts_check_below_limit(&c, limit + ERTS_PCRE_STACK_MARGIN); +} + +static int +stack_guard_upwards(void) +{ + char *limit = ERTS_STACK_LIMIT; + char c; + + ASSERT(limit); + + return erts_check_above_limit(&c, limit - ERTS_PCRE_STACK_MARGIN); +} + void erts_init_bif_re(void) { + char c; erts_pcre_malloc = &erts_erts_pcre_malloc; erts_pcre_free = &erts_erts_pcre_free; erts_pcre_stack_malloc = &erts_erts_pcre_stack_malloc; erts_pcre_stack_free = &erts_erts_pcre_stack_free; + if ((char *) erts_ptr_id(&c) > ERTS_STACK_LIMIT) + erts_pcre_stack_guard = stack_guard_downwards; + else + erts_pcre_stack_guard = stack_guard_upwards; default_table = NULL; /* ISO8859-1 default, forced into pcre */ max_loop_limit = CONTEXT_REDS * LOOP_FACTOR; -- cgit v1.2.3