It has that protection:

ObjectMemory>>isBytes: oop
	"Answer true if the argument contains indexable bytes. See comment in 
formatOf:"
	"Note: Includes CompiledMethods."
	^(self isNonIntegerObject: oop) and:[self isBytesNonInt: oop]

Cheers,
   - Andreas

Robert Withers wrote:
> Why does interpreterProxy->isBytes(interpreterProxy->stackValue(1)) 
> return true for an integer?  It would be better to have protection over 
> the arguments, such that an integer arg would cause a primitiveFailure 
> rather than a seg fault.
> 
> The reason an integer is passed in is from this code:
>>     | addr s |
>>     Socket initializeNetwork.
>>     MessageTally tallySends: [
>>         addr := NetNameResolver addressForName: 'www.google.org'.
>>         (s := SafeSocket new) connectTo: addr port: 80.
>>         s waitForConnectionFor: Socket standardTimeout ifTimedOut: [].
>>     ].
> where the call to NetNameResolver addressForName: 'www.google.org'. 
> returns an integer when it is simulated with tallySends:.  I don't know 
> why simulation of this causes it to do this.
> 
> Rob
> 
> On Oct 3, 2007, at 1:43 PM, John M McIntosh wrote:
> 
>>
>> On Oct 3, 2007, at 11:15 AM, Robert Withers wrote:
>>
>>> This is reproducible and not limited to the vm I specified.
>>
>> Well
>> EXPORT(sqInt) primitiveSocketConnectToPort(void) {
>>     sqInt addr;
>>     sqInt okToConnect;
>>     SocketPtr s;
>>     sqInt socket;
>>     char *address;
>>     sqInt port;
>>
>>     socket = interpreterProxy->stackValue(2);
>>     interpreterProxy->success(interpreterProxy->isBytes(interpreterProxy->stackValue(1))); 
>>
>>     address = ((char *) 
>> (interpreterProxy->firstIndexableField(interpreterProxy->stackValue(1)))); 
>>
>>
>>
>> dies with memory read exception in 
>> interpreterProxy->firstIndexableField()
>>
>> void * firstIndexableField(sqInt oop) {
>> register struct foo * foo = &fum;
>>     sqInt fmt;
>>     sqInt totalLength;
>>     sqInt hdr;
>>     sqInt fixedFields;
>>     sqInt sz;
>>     sqInt class;
>>     sqInt classFormat;
>>     sqInt ccIndex;
>>
>>     hdr = longAt(oop);
>>
>> because oops, via interpreterProxy->stackValue(1)  has the value of 
>> (3)   so it's a number 3, not an oops location (aka 32bit address)
>>
>> longat:(3)  is of course invalid
>>
>>
>> I'd suggest someone look at
>> tryNamedPrimitiveIn: aCompiledMethod for: aReceiver withArgs: arguments
>>
>> to see why it's passing bad data.
>>
>> (gdb) call printAllStacks(0)
>> Process
>> 389589848 ContextPart>tryNamedPrimitiveIn:for:withArgs:
>> 389589756 ContextPart>doPrimitive:method:receiver:args:
>> 389589664 ContextPart>tryPrimitiveFor:receiver:args:
>> 389589204 ContextPart>send:to:with:super:
>> 389589096 ContextPart>send:super:numArgs:
>> 389589004 InstructionStream>interpretExtension:in:for:
>> 389588912 InstructionStream>interpretNextInstructionFor:
>> 389588820 ContextPart>step
>> 389538388 ContextPart>runSimulated:contextAtEachStep:
>> 389538296 MessageTally class>tallySendsTo:inBlock:showTree:
>> 389538112 MessageTally class>tallySends:
>> 389537908 UndefinedObject>DoIt
>> 389532772 Compiler>evaluate:in:to:notifying:ifFail:logged:
>> 389532864 [] in ParagraphEditor>evaluateSelection
>> 389532588 BlockContext>on:do:
>> 389532496 ParagraphEditor>evaluateSelection
>> 389532404 ParagraphEditor>doIt
>> 389532680 [] in ParagraphEditor>doIt:
>> 389532312 Controller>terminateAndInitializeAround:
>> 389532220 ParagraphEditor>doIt:
>> 389531972 ParagraphEditor>dispatchOnCharacter:with:
>> 389531880 TextMorphEditor>dispatchOnCharacter:with:
>> 389531788 ParagraphEditor>readKeyboard
>> 389531696 TextMorphEditor>readKeyboard
>> 389531208 [] in TextMorph>keyStroke:
>> 389531116 TextMorph>handleInteraction:fromEvent:
>> 389531024 TextMorphForEditView>handleInteraction:fromEvent:
>> 389530880 TextMorph>keyStroke:
>> 389530788 TextMorphForEditView>keyStroke:
>> 389530696 TextMorph>handleKeystroke:
>> 389530328 KeyboardEvent>sentTo:
>> 389530236 Morph>handleEvent:
>> 389530144 Morph>handleFocusEvent:
>> 389530420 [] in HandMorph>sendFocusEvent:to:clear:
>> 389530512 [] in PasteUpMorph>becomeActiveDuring:
>> 389530052 BlockContext>on:do:
>> 389529960 PasteUpMorph>becomeActiveDuring:
>> 389529736 HandMorph>sendFocusEvent:to:clear:
>> 389529644 HandMorph>sendEvent:focus:clear:
>> 389529552 HandMorph>sendKeyboardEvent:
>> 389529460 HandMorph>handleEvent:
>> 389529240 HandMorph>processEvents
>> 389529332 [] in WorldState>doOneCycleNowFor:
>> 389529148 SequenceableCollection>do:
>> 389529056 WorldState>handsDo:
>> 389528964 WorldState>doOneCycleNowFor:
>> 389528872 WorldState>doOneCycleFor:
>> 389528780 PasteUpMorph>doOneCycle
>> 386845716 [] in Project class>spawnNewProcess
>> 386845900 [] in BlockContext>newProcess
>>
>>
>> -- 
>> =========================================================================== 
>>
>> John M. McIntosh <johnmci at smalltalkconsulting.com>
>> Corporate Smalltalk Consulting Ltd.  http://www.smalltalkconsulting.com
>> =========================================================================== 
>>
>>
>>
>>
> 
> 
>