topic Re: Taplinx iOS appcrash on tag response in TapLinx SDK, TagWriter and TagInfo

Taplinx iOS appcrash on tag response

DamianD — Wed, 06 Nov 2024 20:09:51 GMT

Hi, i followed UG10045.pdf and created ios application. I created ApduExchangeWithByteArray method and implemented its contents. However when send back response from tag back to taplinx library, application crashes with following entries from device log:

Time Device Name Type PID Tag Message Nov 6 20:44:31 iPhone Notice 5223 MobileFacilityApp Command Set - 1 Nov 6 20:44:31 iPhone Notice 5223 MobileFacilityApp Command Set - Native Nov 6 20:44:31 iPhone Error 0 kernel(Sandbox) Sandbox: MobileFacilityApp(5223) deny(1) sysctl-read kern.bootargs Nov 6 20:44:38 iPhone Notice 5223 MobileFacilityApp(UIKitCore) Received memory warning. Nov 6 20:44:38 iPhone Notice 5223 MobileFacilityApp(UIKitCore) Received memory warning. Nov 6 20:44:40 iPhone Notice 0 kernel EXC_RESOURCE -> MobileFacilityApp[5223] exceeded mem limit: InactiveHard 3072 MB (fatal) Nov 6 20:44:40 iPhone Notice 0 kernel memorystatus: killing process 5223 [MobileFacilityApp] in high band FOREGROUND (100) - memorystatus_available_pages: 44859

When i sent back empty response back to taplinx library (just TL_TagAPDUResponse without setting ResponseData) - app does not crash and i get error about incomplete response (which is expected). What am i doing wrong?

Re: Taplinx iOS appcrash on tag response

DamianD — Thu, 07 Nov 2024 22:04:12 GMT

apparently included headers in TapLinx-v2.0.0 are all wrong. In TapLinxApduHandler.h we see declaration:

- (nullable TL_TagAPDUResponse *)apduExchangeWithByteArray:(NSData *_Nonnull)apduData;

but in reality we should return IOSByteArray*, otherwise app will crash with aforementioned symptoms

Re: Taplinx iOS appcrash on tag response

DamianD — Thu, 07 Nov 2024 22:05:15 GMT

one more thing - apduData is really also IOSByteArray, not NSData

Re: Taplinx iOS appcrash on tag response

ukcas — Fri, 08 Nov 2024 10:12:19 GMT

Hello Damian,

Maybe the cause of the error is some exceeding memory limit and not TapLinx library?

MobileFacilityApp[5223] exceeded mem limit: InactiveHard 3072 MB (fatal)

The application which integrates TapLinx Library can be used as following (no need for ApduExchange implementation on top)

Set the delegate to the APDUHandler

let reader = TL_IOSNFCReader(uid: tag.identifier, historicalBytes: tag.historicalBytes ?? Data()) handler = TapLinxApduHandler(reader: reader) handler.delegate = self libraryManager?.setApduHandlerWithApduHandler(handler)

Next Step will be to implement the protocol method inside the application

func apduExchange(withByteArray apduData: Data) -> TL_TagAPDUResponse? { var tagAPDUResponse: TL_TagAPDUResponse? if connectedTag != nil { // Send Tag Type Native of ISO and the apdu as NFCISO7816APDU executeAPDUCommandOn7816Tag(tagType: tagtype, apdu: apdu) { data in let appendedData = data tagAPDUResponse = TL_TagAPDUResponse(responseData: appendedData, tag: self.currentTag) semaphore.signal() } let _ = semaphore.wait(timeout: .now() + 3.0) } else if connectedMifareTag != nil { let semaphore = DispatchSemaphore(value: 0) print("MIFARE CAPDU -> \(apduData.hex)") executeAPDUCommandOnMIFARETag(apdu: apduData) { data in print("RAPDU <- Data: \(data.hex)") tagAPDUResponse = TL_TagAPDUResponse(responseData: data, tag: self.currentTag) semaphore.signal() } let _ = semaphore.wait(timeout: .now() + 3.0) } print("Tag Response \(String(describing: tagAPDUResponse))") return tagAPDUResponse }

Hope this simplification would help you.

Best regards,

TapLinx team

Re: Taplinx iOS appcrash on tag response

DamianD — Fri, 08 Nov 2024 10:30:25 GMT

hi
the crash definietly comes from taplinx library because when i changed
- (nullable TL_TagAPDUResponse *)apduExchangeWithByteArray:(NSData *_Nonnull)apduData;
to actually:
- (nullable IOSByteArray*)apduExchangeWithByteArray:(IOSByteArray*_Nonnull)apduData;
It started working

Re: Taplinx iOS appcrash on tag response

DamianD — Fri, 08 Nov 2024 11:00:30 GMT

@ukcas - what version of taplinx ios library is 'current'? Because i have 2.0.0 and it definitely crashes when i return TL_TagAPDUResponse from apduExchange method, it has to be raw IOSByteArray from j2objc library. I'm using c# bindings for taplinx library, but it does not matter in this problem.

Re: Taplinx iOS appcrash on tag response

DamianD — Fri, 08 Nov 2024 11:42:39 GMT

followup - when i changed my implementation to use provided TapLinxApduHandler instead of providing my own - then apduExchangeWithByteArray does conform to contract - (nullable TL_TagAPDUResponse *)apduExchangeWithByteArray:(NSData *_Nonnull)apduData;