Port COSGN00C (Identity & Access / Signon) to C# .NET 8 (one-to-one)

[matthewguerra-cog]

Summary

One-to-one port of app/cbl/COSGN00C.cbl (transaction CC00, signon) to C# on .NET 8 under a new dotnet/ tree. No COBOL was touched. Requested against ankehao-demo/aws-mainframe-modernization-carddemo, but Devin has no push access there (push: false, 403), so this lands on the COG-GTM fork — the COBOL/copybook sources are byte-identical between the two.

Paragraph → method, statement order preserved, no consolidation:

COBOL	C# (dotnet/CardDemo.Identity/Cosgn00c.cs)
MAIN-PARA	MainPara(TerminalInput eib)
PROCESS-ENTER-KEY	ProcessEnterKey()
SEND-SIGNON-SCREEN	SendSignonScreen()
SEND-PLAIN-TEXT	SendPlainText()
POPULATE-HEADER-INFO	PopulateHeaderInfo()
READ-USER-SEC-FILE	ReadUserSecFile()

Copybooks → types with the exact PIC lengths: COCOM01Y → CardDemoCommarea (incl. the 88 levels as CdemoUsrtypAdmin/CdemoUsrtypUser/CdemoPgmEnter/CdemoPgmReenter), CSUSR01Y → SecUserData (SecUsrId X(8), SecUsrFname X(20), SecUsrLname X(20), SecUsrPwd X(8), SecUsrType X(1), SecUsrFiller X(23)), COSGN00.CPY → Cosgn0aMap (single object because COSGN0AO REDEFINES COSGN0AI; UseridL/PasswdL carry the -1 cursor), CSMSG01Y/COTTL01Y → CcdaCommonMessages/CcdaScreenTitle literals copied verbatim including trailing blanks of the PIC X(50)/X(40) VALUE clauses.

CICS is abstracted only at the boundary: ICicsTerminal (RECEIVE MAP / SEND MAP / SEND TEXT / ASSIGN APPLID+SYSID), IUserSecurityFile.Read(dataset, key, into) returning the raw RESP code (0 / 13 / other, CicsRespCodes), IProgramControl.Xctl(program, commarea), and TerminalInput(EibCalen, EibAid) for the EIB fields. CobolString reproduces MOVE truncate/space-pad, SPACES/LOW-VALUES comparison and FUNCTION UPPER-CASE (invariant).

Faithfulness details worth calling out:

• The uppercasing MOVEs sit after the EVALUATE in PROCESS-ENTER-KEY, so they run on the empty-User-ID / empty-Password branches too; the IF NOT ERR-FLG-ON guard is what suppresses the read. Preserved literally — CdemoUserId is populated even when validation failed and no read happens.
• SEND-PLAIN-TEXT issues a bare EXEC CICS RETURN, and XCTL never returns, so neither path reaches MAIN-PARA's RETURN TRANSID('CC00'). Modeled with an internal _taskEnded flag rather than exceptions; observable via ReturnTransid (null on those paths) and XctlProgram.
• CARDDEMO-COMMAREA is WORKING-STORAGE in the COBOL (DFHCOMMAREA is never copied in), so CarddemoCommarea starts blank per invocation and only EIBCALEN is consumed from the passed commarea.
• Wrong-password does not set WS-ERR-FLG in the COBOL (only the message + cursor); kept as-is.
• Non-admin user types other than 'U' fall to the ELSE and route to COMEN01C (covered by a test).

Copybooks were all located in app/cpy/ (CSUSR01Y.cpy, CSMSG01Y.cpy, COTTL01Y.cpy, CSDAT01Y.cpy), so no field layouts or literals were invented. Only assumption: FUNCTION CURRENT-DATE is injected as Func<DateTime> (defaults to DateTime.Now) so header date/time (mm/dd/yy, hh:mm:ss from CSDAT01Y) is deterministic in tests.

Security preserved as-is (not modernized): password comparison is plaintext after uppercasing, USRSEC is read-only, and there is no lockout, retry counter, or audit logging — exactly as in the COBOL. Do not treat this port as hardened authentication.

Tests

dotnet/CardDemo.Identity.Tests/Cosgn00cTests.cs, xUnit, dotnet test → 19 passed / 0 failed:

EIBCALEN=0 sends the screen with cursor on User ID and no read · header fields populated (titles, CC00, COSGN00C, date/time, applid/sysid) · PF3 sends the CCDA-MSG-THANK-YOU plain text, no map, no routing · unknown key shows CCDA-MSG-INVALID-KEY and redisplays · empty User ID (spaces and low-values) → "Please enter User ID ..." with cursor on User ID, no read · empty Password (spaces and low-values) → "Please enter Password ..." with cursor on Password, no read · CDEMO-USER-ID still uppercased on the error branch · valid admin → commarea (CC00, COSGN00C, uppercased id, type A, context 0) and XCTL COADM01C · valid user → COMEN01C · type X → COMEN01C · wrong password → "Wrong Password. Try again ..." cursor Password, no routing · RESP 13 → "User not found. Try again ..." cursor User ID · other RESP → "Unable to verify the User ..." cursor User ID · lowercase admin001/password uppercased before lookup and compare · read targets dataset USRSEC · pseudo-conversational retry (failed then successful signon) · stored record unchanged after signon.

Devin-Org: engineering

Link to Devin session: https://app.devin.ai/sessions/550ae3504118489782ce5cddc3712d0f
Requested by: @matthewguerra-cog

---

Devin Review

Status	Commit
🟢 Reviewed	33e6c1f

[devin-ai-integration]

🤖 Devin AI Engineer

I'll be helping with this pull request! Here's what you should know:

✅ I will automatically:

• Address comments on this PR. Add '(aside)' to your comment to have me ignore it.
• Look at CI failures and help fix them

Note: I can only respond to comments from users who have write access to this repository.

⚙️ Control Options:

• Disable automatic comment, CI, and merge conflict monitoring