vms-6a1: SHOW USERS fails honestly with no executive (INV-6 fabrication fix)

[baron-3dl]

Defect (vms-6a1, INV-6 / Rule 9)

cmd_show_users() in src/vmsdcl/dcl_cmd_show.c printed its banner and the
Total number of users = N, number of processes = M summary
unconditionally, then returned SS$_NORMAL, without ever checking whether
the process-table scan reached the executive. With /dev/vms absent the first
vms_kif_procscan() cannot be delivered, process_count stays 0, and the code
still printed ...number of processes = 0 and reported success -- a fabricated
system display with no executive behind it.

The status contract (task premise corrected)

The task assumed vms_kif_procscan() returns SS$_NOSUCHDEV when absent. It
does not: the bare KIF_CALL path maps a bad-fd ioctl through
vms_kif_kerr_to_ss() -> default -> SS$_BUGCHECK (676). The real
distinguisher is that the executive answers with SS$_NORMAL (a row) or
SS$_NONEXPR (2280, table exhausted); anything else means the transport
never reached the executive. Gate: readable = (scan_st & 1) || scan_st == SS$_NONEXPR.

Adjudication — no-executive frame matches SHOW SYSTEM (a made-call)

My first fix emitted %SYSTEM-W-NOSUCHDEV and returned, dropping the
banner+headings. That satisfied the QEMU negctl but broke two host tests
(test_show_users_full, test_show_users_terminal) which require the frame --
and those host tests had always contradicted the negctl on one line: the
negctl forbids number of processes with no executive, the host test EXPECTed
Total number of users on the same line (main: host-green, negctl-red).

Controlling precedent = SHOW SYSTEM. cmd_show_system /
test_show_system_no_fabrication.sh: with no executive it prints banner +
column headings + NO rows and no computed count line. SHOW USERS is the only
SHOW command that prints a walked count; a count from a scan that hard-failed
is a mild fabrication (claims "I enumerated 0" when the truth is "I could not
enumerate"). So the faithful behavior, matching SHOW SYSTEM:

1. cmd_show_users: keep the first-scan readable gate. Executive-unreadable
   branch prints the same frame SHOW SYSTEM does -- banner + column headings
   (honouring the bare-vs-/FULL split) + NO rows + NO count line -- and
   returns SS$_NORMAL. The count line prints only when the table was readable,
   including readable-but-empty (SS$_NONEXPR -> honest = 0).
2. test_show_users_terminal.sh (a strengthening): removed
   EXPECT: contains:Total number of users, added
   EXPECT_NOT: contains:number of processes; every other assertion
   (Username/Node/Interactive headings; no PID/terminal/_FTA rows) unchanged;
   header comment records why. This overrides a documented test-author
   choice and reconciles the host contract to SHOW SYSTEM + the negctl.
3. test_show_users_full.sh: unchanged; passes (checks /FULL headings + no
   rows; the frame still prints).
4. test_syssvc_spawn_users.c (QEMU negctl): unchanged; its
   !has_substr(out,"number of processes") now matches the code.

Verification

Device-absent SHOW USERS (real DCL.EXE, no /dev/vms):

      OpenVMX User Processes at 28-AUG-2026 13:55:38.59
      Username     Node       Interactive  Subprocess     Batch

SHOW USERS/FULL:

      OpenVMX User Processes at 28-AUG-2026 13:55:38.59
      Username     Node       Process Name      PID        Terminal

• No number of processes substring; banner + headings present; no rows.
• ctest -R dcl-integration -> PASS (was test docs vms-b33: Phase 2 verdict, tenth run -- GO #124, the failing one);
  harness runs both show_users scripts -> both PASS.
• ctest -R show -> 5/5 pass. QEMU negctl binary exits 77.

🤖 Generated with Claude Code