MSGW in HTTPAPIR4

[pshanmugam]

Hello Scott Klement,
There are couple of MSGW recently started happening in Production in HTTPAPIR4. These programs were running fine in Production for atleast 4 months without any issue.

Following are the error details:
1. Pointer not set for location referenced. Function check. MCH3601 unmonitored by HTTPAPIR4 at statement 0000004844, instruction X'0000'.
Call stack: Program -> HTTP_PERSIST_REQ -> DO_OPER -> SENDREQ -> COMMTCP_BLOCKWRITE

2. Space offset X'00FFF000' or X'0000000000000000' is outside current limit for object MYJOBNAME JOBUSER JOBNUMBER. Function check. MCH3601 unmonitored by HTTPAPIR4 at statement 0000004880, instruction X'0000'.
Call stack: Program -> HTTP_URL_POST -> HTTP_URL_POST_RAW -> HTTP_PERSIST_POST -> HTTP_PERSIST_REQ -> DO_OPER -> SENDDOC -> COMMTCP_BLOCKWRITE

Production has version 1.29. Please suggest.

[Scott Klement]

What are you passing for the data to send and length of data when you call http_url_post()?

It would appear that either the pointer you're sending is not valid, or the length is too large and so it is exceeding the size of the space.

[pshanmugam]

Thanks Scott. The maximum length of the field passed is 65535. Code snippet below.

D myJSON S 65535A varying

%len(myJSON) = %len(myJSON:*MAX);
yajl_copyBuf( CCSID
: %addr(myJSON:*data)
: %len(myJSON)
: length );

%len(myJSON) = length;

rc = http_url_post( URL
: %addr( myJSON : *data )
: %len( myJSON )
: %Trim(LogFile)
: HTTP_TIMEOUT
: HTTP_USERAGENT
: 'application/json; charset=UTF-8');

Also noticed the source HTTPAPIR4, where SENDREQ & SENDDOC calls COMM_BLOCKWRITE and not COMMTCP_BLOCKWRITE (as per call stack). Not sure this has anything to do.

[pshanmugam]

For http_persist_req, code snippet is as below:

D myJSON S 65535a varying
D pointer S *

yajl_copyBuf( CCSID
: %addr(myJSON)
: %size(myJSON)
: length );
myJSON = '{' + %Trim(myJSON) + '}';

Pointer = http_persist_open( URL);

rc = http_persist_req( 'PUT'
: pointer
: URL
: 0
: *null
: %addr( myJSON : *data )
: %len( myJSON )
: 0
: %pAddr(Proc)
: HTTP_TIMEOUT
: HTTP_USERAGENT
: 'application/json' );

PProc B
D Pi 10i 0
D fd 10i 0 value
D data * value
D length 10i 0 value
C*
/Free
return length;
/End-Free
P E

[Scott Klement]

Nothing in the code you've posted would cause the errors you're reporting. The first error means that a parameter was passed with a *NULL address. The second error means that you've exceeded the amount of memory allocated to a space. The code you've posted doesn't appear to do that.

Can you post a complete program (rather than these small snippets) that I can run to reproduce the problem?

[fallingrock]

1. Pointer not set for location referenced. Function check. MCH3601 unmonitored by HTTPAPIR4 at statement 0000004844, instruction X'0000'.
Call stack: Program -> HTTP_PERSIST_REQ -> DO_OPER -> SENDREQ -> COMMTCP_BLOCKWRITE

2. Space offset X'00FFF000' or X'0000000000000000' is outside current limit for object MYJOBNAME JOBUSER JOBNUMBER. Function check. MCH3601 unmonitored by HTTPAPIR4 at statement 0000004880, instruction X'0000'.
Call stack: Program -> HTTP_URL_POST -> HTTP_URL_POST_RAW -> HTTP_PERSIST_POST -> HTTP_PERSIST_REQ -> DO_OPER -> SENDDOC -> COMMTCP_BLOCKWRITE

FWIW: I encountered the same problem recently ... the program was communicating with a java server running on Linux.

As best as I can determine, the Java server crashed in the middle of the data transfer and that caused an invalid length to be returned by the send procedure in the CommTcp_BlockWrite procedure. When the length (wwLen) was added to peBuffer, the pointer space extended outside the job space causing the MCH3601.

I have no idea what kind of crash in the Java application could cause that though.

david

[Scott Klement]

Hi David,

Are you able to reproduce this problem? I have an idea that might fix it, but no way to test it since I can't reproduce.

[fallingrock]

Unfortunately, I'm unable to reproduce the error ... it's entirely theoretical. I based my comment on the fact that we crashed at the specific line where we incremented peBuffer by wwLen.