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Merge pull request #69 from messense/timeout
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Add timeout and max_memory limit support
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@Taiki-San
Taiki-San authored Dec 24, 2018
2 parents c0df8e0 + aa34a52 commit 8d8c3f6
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Showing 3 changed files with 121 additions and 16 deletions.
76 changes: 67 additions & 9 deletions py_mini_racer/extension/mini_racer_extension.cc
View file
Original file line number Diff line number Diff line change
Expand Up @@ -35,6 +35,8 @@ enum BinaryTypes {

type_execute_exception = 200,
type_parse_exception = 201,
type_oom_exception = 202,
type_timeout_exception = 203,
};

/* This is a generic store for arbitrary JSON like values.
Expand Down Expand Up @@ -63,6 +65,8 @@ void BinaryValueFree(BinaryValue *v) {
switch(v->type) {
case type_execute_exception:
case type_parse_exception:
case type_oom_exception:
case type_timeout_exception:
case type_str_utf8:
free(v->str_val);
break;
Expand Down Expand Up @@ -119,6 +123,7 @@ struct EvalResult {
bool parsed;
bool executed;
bool terminated;
bool timed_out;
Persistent<Value>* value;
Persistent<Value>* message;
Persistent<Value>* backtrace;
Expand All @@ -144,10 +149,31 @@ typedef struct {
Local<String>* eval;
useconds_t timeout;
EvalResult* result;
size_t max_memory;
} EvalParams;

enum IsolateFlags {
MEM_SOFTLIMIT_VALUE,
MEM_SOFTLIMIT_REACHED,
};

static Platform* current_platform = NULL;

static void gc_callback(Isolate *isolate, GCType type, GCCallbackFlags flags) {
if((bool)isolate->GetData(MEM_SOFTLIMIT_REACHED)) return;

size_t softlimit = *(size_t*) isolate->GetData(MEM_SOFTLIMIT_VALUE);

HeapStatistics stats;
isolate->GetHeapStatistics(&stats);
size_t used = stats.used_heap_size();

if(used > softlimit) {
isolate->SetData(MEM_SOFTLIMIT_REACHED, (void*)true);
isolate->TerminateExecution();
}
}

static void init_v8() {
if (current_platform == NULL) {
V8::InitializeICU();
Expand All @@ -161,6 +187,7 @@ static void* breaker(void *d) {
EvalParams* data = (EvalParams*)d;
usleep(data->timeout*1000);
pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, NULL);
data->result->timed_out = true;
data->context_info->isolate->TerminateExecution();
return NULL;
}
Expand All @@ -178,10 +205,16 @@ static void* nogvl_context_eval(void* arg) {

Context::Scope context_scope(context);

// Memory softlimit
isolate->SetData(MEM_SOFTLIMIT_VALUE, (void*)false);
// Memory softlimit hit flag
isolate->SetData(MEM_SOFTLIMIT_REACHED, (void*)false);

MaybeLocal<Script> parsed_script = Script::Compile(context, *eval_params->eval);
result->parsed = !parsed_script.IsEmpty();
result->executed = false;
result->terminated = false;
result->timed_out = false;
result->value = NULL;

if (!result->parsed) {
Expand All @@ -191,10 +224,16 @@ static void* nogvl_context_eval(void* arg) {

pthread_t breaker_thread = 0;

// timeout limit
auto timeout = eval_params->timeout;
if (timeout > 0) {
pthread_create(&breaker_thread, NULL, breaker, (void*)eval_params);
}
// memory limit
if (eval_params->max_memory > 0) {
isolate->SetData(MEM_SOFTLIMIT_VALUE, &eval_params->max_memory);
isolate->AddGCEpilogueCallback(gc_callback);
}

MaybeLocal<Value> maybe_value = parsed_script.ToLocalChecked()->Run(context);

Expand All @@ -204,7 +243,6 @@ static void* nogvl_context_eval(void* arg) {
}

result->executed = !maybe_value.IsEmpty();

if (!result->executed) {
if (trycatch.HasCaught()) {
if (!trycatch.Exception()->IsNull()) {
Expand All @@ -213,7 +251,12 @@ static void* nogvl_context_eval(void* arg) {
} else if(trycatch.HasTerminated()) {
result->terminated = true;
result->message = new Persistent<Value>();
Local<String> tmp = String::NewFromUtf8(isolate, "JavaScript was terminated (either by timeout or explicitly)");
Local<String> tmp;
if (result->timed_out) {
tmp = String::NewFromUtf8(isolate, "JavaScript was terminated by timeout");
} else {
tmp = String::NewFromUtf8(isolate, "JavaScript was terminated");
}
result->message->Reset(isolate, tmp);
}

Expand Down Expand Up @@ -497,7 +540,8 @@ ContextInfo *MiniRacer_init_context()

static BinaryValue* MiniRacer_eval_context_unsafe(
ContextInfo *context_info,
char *utf_str, int str_len)
char *utf_str, int str_len,
unsigned long timeout, size_t max_memory)
{
EvalParams eval_params;
EvalResult eval_result{};
Expand Down Expand Up @@ -529,9 +573,13 @@ static BinaryValue* MiniRacer_eval_context_unsafe(
eval_params.eval = &eval;
eval_params.result = &eval_result;
eval_params.timeout = 0;

// FIXME - we should allow setting a timeout here
// eval_params.timeout = (useconds_t)NUM2LONG(timeout);
eval_params.max_memory = 0;
if (timeout > 0) {
eval_params.timeout = (useconds_t)timeout;
}
if (max_memory > 0) {
eval_params.max_memory = max_memory;
}

nogvl_context_eval(&eval_params);

Expand Down Expand Up @@ -571,9 +619,19 @@ static BinaryValue* MiniRacer_eval_context_unsafe(

else if (!eval_result.executed) {
result = xalloc(result);
result->type = type_execute_exception;
result->str_val = nullptr;

bool mem_softlimit_reached = (bool)context_info->isolate->GetData(MEM_SOFTLIMIT_REACHED);
if (mem_softlimit_reached) {
result->type = type_oom_exception;
} else {
if (eval_result.timed_out) {
result->type = type_timeout_exception;
} else {
result->type = type_execute_exception;
}
}

if (bmessage && bmessage->type == type_str_utf8 &&
bbacktrace && bbacktrace->type == type_str_utf8) {
// +1 for \n, +1 for NUL terminator
Expand Down Expand Up @@ -639,8 +697,8 @@ class BufferOutputStream: public OutputStream {

extern "C" {

BinaryValue* mr_eval_context(ContextInfo *context_info, char *str, int len) {
BinaryValue *res = MiniRacer_eval_context_unsafe(context_info, str, len);
BinaryValue* mr_eval_context(ContextInfo *context_info, char *str, int len, unsigned long timeout, size_t max_memory) {
BinaryValue *res = MiniRacer_eval_context_unsafe(context_info, str, len, timeout, max_memory);
return res;
}

Expand Down
40 changes: 33 additions & 7 deletions py_mini_racer/py_mini_racer.py
View file
Original file line number Diff line number Diff line change
Expand Up @@ -35,6 +35,14 @@ class JSEvalException(MiniRacerBaseException):
""" JS could not be executed """
pass

class JSOOMException(JSEvalException):
""" JS execution out of memory """
pass

class JSTimeoutException(JSEvalException):
""" JS execution timed out """
pass

class JSConversionException(MiniRacerBaseException):
""" type could not be converted """
pass
Expand Down Expand Up @@ -88,7 +96,9 @@ def _fetch_ext_handle():
_ext_handle.mr_eval_context.argtypes = [
ctypes.c_void_p,
ctypes.c_char_p,
ctypes.c_int]
ctypes.c_int,
ctypes.c_ulong,
ctypes.c_size_t]
_ext_handle.mr_eval_context.restype = ctypes.POINTER(PythonValue)

_ext_handle.mr_free_value.argtypes = [ctypes.c_void_p]
Expand Down Expand Up @@ -123,31 +133,37 @@ def free(self, res):

self.ext.mr_free_value(res)

def execute(self, js_str):
def execute(self, js_str, timeout=0, max_memory=0):
""" Exec the given JS value """

wrapped = "(function(){return (%s)})()" % js_str
return self.eval(wrapped)
return self.eval(wrapped, timeout, max_memory)

def eval(self, js_str):
def eval(self, js_str, timeout=0, max_memory=0):
""" Eval the JavaScript string """

if is_unicode(js_str):
bytes_val = js_str.encode("utf8")
else:
bytes_val = js_str

res = None
self.lock.acquire()
try:
res = self.ext.mr_eval_context(self.ctx, bytes_val, len(bytes_val))
res = self.ext.mr_eval_context(self.ctx,
bytes_val,
len(bytes_val),
ctypes.c_ulong(timeout),
ctypes.c_size_t(max_memory))

if bool(res) is False:
raise JSConversionException()
python_value = res.contents.to_python()
return python_value
finally:
self.lock.release()
self.free(res)
if res is not None:
self.free(res)

def call(self, identifier, *args, **kwargs):
""" Call the named function with provided arguments
Expand All @@ -156,10 +172,12 @@ def call(self, identifier, *args, **kwargs):
"""

encoder = kwargs.get('encoder', None)
timeout = kwargs.get('timeout', 0)
max_memory = kwargs.get('max_memory', 0)

json_args = json.dumps(args, separators=(',', ':'), cls=encoder)
js = "{identifier}.apply(this, {json_args})"
return self.eval(js.format(identifier=identifier, json_args=json_args))
return self.eval(js.format(identifier=identifier, json_args=json_args), timeout, max_memory)

def heap_stats(self):
""" Return heap statistics """
Expand Down Expand Up @@ -210,6 +228,8 @@ class PythonTypes(object):

execute_exception = 200
parse_exception = 201
oom_exception = 202
timeout_exception = 203


class PythonValue(ctypes.Structure):
Expand Down Expand Up @@ -273,6 +293,12 @@ def to_python(self):
elif self.type == PythonTypes.execute_exception:
msg = ctypes.c_char_p(self.value).value
raise JSEvalException(msg.decode('utf-8', errors='replace'))
elif self.type == PythonTypes.oom_exception:
msg = ctypes.c_char_p(self.value).value
raise JSOOMException(msg)
elif self.type == PythonTypes.timeout_exception:
msg = ctypes.c_char_p(self.value).value
raise JSTimeoutException(msg)
elif self.type == PythonTypes.date:
timestamp = self._double_value()
# JS timestamp are milliseconds, in python we are in seconds
Expand Down
21 changes: 21 additions & 0 deletions tests/test_eval.py
View file
Original file line number Diff line number Diff line change
Expand Up @@ -3,6 +3,7 @@

""" Basic JS types tests """

import time
import unittest
import six

Expand Down Expand Up @@ -75,6 +76,26 @@ def test_null_byte(self):
result = context.eval(in_val)
self.assertEqual(result, s)

def test_timeout(self):
timeout_ms = 100
with self.assertRaises(py_mini_racer.JSTimeoutException):
start_time = time.clock()
self.mr.eval('while(1) { }', timeout=timeout_ms)
duration = time.clock() - start_time
assert timeout_ms <= duration * 1000 <= timeout_ms + 10

def test_max_memory(self):
with self.assertRaises(py_mini_racer.JSOOMException):
self.mr.eval('''let s = 1000;
var a = new Array(s);
a.fill(0);
while(true) {
s *= 1.1;
let n = new Array(Math.floor(s));
n.fill(0);
a = a.concat(n);
}''', max_memory=200000000)


if __name__ == '__main__':
import sys
Expand Down

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