Stack guard for PCRE

3 files changed, 93 insertions, 17 deletions

diff --git a/erts/lib_src/common/ethr_aux.c b/erts/lib_src/common/ethr_aux.c
index 3501fe335a..bbffca4d6d 100644
--- a/erts/lib_src/common/ethr_aux.c
+++ b/erts/lib_src/common/ethr_aux.c
@@ -68,6 +68,8 @@ size_t ethr_max_stack_size__; /* kilo words */
 ethr_rwmutex xhndl_rwmtx;
 ethr_xhndl_list *xhndl_list;
 
+static ethr_tsd_key ethr_stacklimit_key__;
+
 static int main_threads;
 
 static int init_ts_event_alloc(void);
@@ -237,13 +239,11 @@ ethr_init_common__(ethr_init_data *id)
 #endif
     ethr_min_stack_size__ = ETHR_PAGE_ALIGN(ethr_min_stack_size__);
 
-    ethr_min_stack_size__ = ETHR_B2KW(ethr_min_stack_size__);
-
     ethr_max_stack_size__ = 32*1024*1024;
 #if SIZEOF_VOID_P == 8
     ethr_max_stack_size__ *= 2;
 #endif
-    ethr_max_stack_size__ = ETHR_B2KW(ethr_max_stack_size__);
+    ethr_max_stack_size__ = ETHR_PAGE_ALIGN(ethr_max_stack_size__);
 
     res = ethr_init_atomics();
     if (res != 0)
@@ -253,6 +253,10 @@ ethr_init_common__(ethr_init_data *id)
     if (res != 0)
 	return res;
 
+    res = ethr_tsd_key_create(&ethr_stacklimit_key__, "stacklimit");
+    if (res != 0)
+        return res;
+
     xhndl_list = NULL;
 
     return 0;
@@ -313,6 +317,60 @@ ethr_late_init_common__(ethr_late_init_data *lid)
     return 0;
 }
 
+/*
+ * Stack limit
+ */
+
+void *ethr_get_stacklimit(void)
+{
+    return ethr_tsd_get(ethr_stacklimit_key__);
+}
+
+int ethr_set_stacklimit(void *limit)
+{
+    void *prev = ethr_tsd_get(ethr_stacklimit_key__);
+    if (prev)
+        return EACCES;
+    if (!limit)
+        return EINVAL;
+    return ethr_tsd_set(ethr_stacklimit_key__, limit);
+}
+
+/* internal stacklimit (thread creation) */
+
+void
+ethr_set_stacklimit__(char *prev_c, size_t stacksize)
+{
+    /*
+     * We *don't* want this function inlined, i.e., it is
+     * risky to call this function from another function
+     * in ethr_aux.c
+     */
+    void *limit = NULL;
+    char c;
+    int res;
+
+    if (stacksize) {
+        char *start;
+        if (&c > prev_c) {
+            start = (char *) ((((ethr_uint_t) prev_c)
+                               / ethr_pagesize__)
+                              * ethr_pagesize__);
+            limit = start + stacksize;
+        }
+        else {
+            start = (char *) (((((ethr_uint_t) prev_c) - 1)
+                               / ethr_pagesize__ + 1)
+                              * ethr_pagesize__);
+            limit = start - stacksize;
+        }
+    }
+
+    res = ethr_tsd_set(ethr_stacklimit_key__, limit);
+    if (res != 0)
+        ethr_abort__();
+}
+
 int
 ethr_install_exit_handler(void (*funcp)(void))
 {
diff --git a/erts/lib_src/pthread/ethread.c b/erts/lib_src/pthread/ethread.c
index 29bffa7e12..f0d4296445 100644
--- a/erts/lib_src/pthread/ethread.c
+++ b/erts/lib_src/pthread/ethread.c
@@ -81,6 +81,7 @@ typedef struct {
     void *(*thr_func)(void *);
     void *arg;
     void *prep_func_res;
+    size_t stacksize;
     char *name;
     char name_buff[16];
 } ethr_thr_wrap_data__;
@@ -88,12 +89,15 @@ typedef struct {
 static void *thr_wrapper(void *vtwd)
 {
     ethr_sint32_t result;
+    char c;
     void *res;
     ethr_thr_wrap_data__ *twd = (ethr_thr_wrap_data__ *) vtwd;
     void *(*thr_func)(void *) = twd->thr_func;
     void *arg = twd->arg;
     ethr_ts_event *tsep = NULL;
 
+    ethr_set_stacklimit__(&c, twd->stacksize);
+
     result = (ethr_sint32_t) ethr_make_ts_event__(&tsep);
 
     if (result == 0) {
@@ -330,6 +334,7 @@ ethr_thr_create(ethr_tid *tid, void * (*func)(void *), void *arg,
     twd.tse = ethr_get_ts_event();
     twd.thr_func = func;
     twd.arg = arg;
+    twd.stacksize = 0;
 
     if (opts && opts->name) {
         snprintf(twd.name_buff, 16, "%s", opts->name);
@@ -354,18 +359,24 @@ ethr_thr_create(ethr_tid *tid, void * (*func)(void *), void *arg,
 #ifdef ETHR_DEBUG
 	suggested_stack_size /= 2; /* Make sure we got margin */
 #endif
+        stack_size = ETHR_KW2B(suggested_stack_size);
+        stack_size = ETHR_PAGE_ALIGN(stack_size);
+        stack_size += ethr_pagesize__; /* For possible system usage */
 #ifdef ETHR_STACK_GUARD_SIZE
 	/* The guard is at least on some platforms included in the stack size
 	   passed when creating threads */
-	suggested_stack_size += ETHR_B2KW(ETHR_STACK_GUARD_SIZE);
+	stack_size += ETHR_STACK_GUARD_SIZE;
 #endif
-	if (suggested_stack_size < ethr_min_stack_size__)
-	    stack_size = ETHR_KW2B(ethr_min_stack_size__);
-	else if (suggested_stack_size > ethr_max_stack_size__)
-	    stack_size = ETHR_KW2B(ethr_max_stack_size__);
-	else
-	    stack_size = ETHR_PAGE_ALIGN(ETHR_KW2B(suggested_stack_size));
+	if (stack_size < ethr_min_stack_size__)
+	    stack_size = ethr_min_stack_size__;
+	else if (stack_size > ethr_max_stack_size__)
+	    stack_size = ethr_max_stack_size__;
 	(void) pthread_attr_setstacksize(&attr, stack_size);
+        twd.stacksize = stack_size;
+        twd.stacksize -= ethr_pagesize__; /* For possible system usage */
+#ifdef ETHR_STACK_GUARD_SIZE
+        twd.stacksize -= ETHR_STACK_GUARD_SIZE;
+#endif
     }
 
 #ifdef ETHR_STACK_GUARD_SIZE
diff --git a/erts/lib_src/win/ethread.c b/erts/lib_src/win/ethread.c
index e0f19f7ba1..ba77b3dc88 100644
--- a/erts/lib_src/win/ethread.c
+++ b/erts/lib_src/win/ethread.c
@@ -56,6 +56,7 @@ typedef struct {
     void *(*thr_func)(void *);
     void *arg;
     void *prep_func_res;
+    size_t stacksize;
 } ethr_thr_wrap_data__;
 
 #define ETHR_INVALID_TID_ID -1
@@ -94,6 +95,7 @@ static void thr_exit_cleanup(ethr_tid *tid, void *res)
 
 static unsigned __stdcall thr_wrapper(LPVOID vtwd)
 {
+    char c;
     ethr_tid my_tid;
     ethr_sint32_t result;
     void *res;
@@ -102,6 +104,8 @@ static unsigned __stdcall thr_wrapper(LPVOID vtwd)
     void *arg = twd->arg;
     ethr_ts_event *tsep = NULL;
 
+    ethr_set_stacklimit__(&c, twd->stacksize);
+
     result = (ethr_sint32_t) ethr_make_ts_event__(&tsep);
 
     if (result == 0) {
@@ -305,18 +309,21 @@ ethr_thr_create(ethr_tid *tid, void * (*func)(void *), void *arg,
 	tid->jdata->res = NULL;
     }
 
+    twd.stacksize = 0;
+
     if (use_stack_size >= 0) {
 	size_t suggested_stack_size = (size_t) use_stack_size;
 #ifdef ETHR_DEBUG
 	suggested_stack_size /= 2; /* Make sure we got margin */
 #endif
-	if (suggested_stack_size < ethr_min_stack_size__)
-	    stack_size = (unsigned) ETHR_KW2B(ethr_min_stack_size__);
-	else if (suggested_stack_size > ethr_max_stack_size__)
-	    stack_size = (unsigned) ETHR_KW2B(ethr_max_stack_size__);
-	else
-	    stack_size = (unsigned)
-	      ETHR_PAGE_ALIGN(ETHR_KW2B(suggested_stack_size));
+        stack_size = (unsigned) ETHR_PAGE_ALIGN(ETHR_KW2B(suggested_stack_size));
+
+	if (stack_size < (unsigned) ethr_min_stack_size__)
+	    stack_size = (unsigned) ethr_min_stack_size__;
+	else if (stack_size > (unsigned) ethr_max_stack_size__)
+	    stack_size = (unsigned) ethr_max_stack_size__;
+
+        twd.stacksize = stack_size;
     }
 
     ethr_atomic32_init(&twd.result, -1);