vms-706: build vms_stdio.c + vms_futex.c on VAX (close the freestanding-facility gap)

src/libvmssys/CMakeLists.txt

@@ -52,15 +52,17 @@ if(VMSSYS_SUBSTRATE STREQUAL "netbsd")
     # Link-libc build set: substrate-agnostic VMS RTL + kif policy + NetBSD
     # transport leaf. Excluded on purpose (design §4.1):
     #   * vms_runtime_init.c    -- hand-rolled auxv/TLS; NetBSD csu/libc does it.
-    #   * vms_stdio.c/vms_futex.c -- freestanding buffered-I/O + futex sync,
-    #     superseded by NetBSD libc/libpthread; they also use VMS_O_*/futex
-    #     wrappers whose per-substrate constant resolution is a deferred audit
-    #     item (docs/design-ovmx-netbsd-syskrnl.md §4.2).
     #   * kif_transport_linux.c -- replaced by kif_transport_netbsd.c.
+    # vms_stdio.c + vms_futex.c ARE built here now (vms-706): their VMS_O_*/futex
+    # wrappers resolve per-substrate (vms_sys_openat/vms_sys_futex over NetBSD
+    # openat(2)/__futex(2); VMS_O_*/VMS_FUTEX_* alias <fcntl.h>/<sys/futex.h>),
+    # closing the freestanding-facility gap so the same sources build on VAX.
     set(VMSSYS_C_SOURCES
         vms_string.c
         vms_snprintf.c
         vms_math.c
+        vms_stdio.c
+        vms_futex.c
         vms_kif.c
         kif_transport_netbsd.c
     )

src/libvmssys/arch/vax/vms_syscall_netbsd.h

@@ -43,6 +43,8 @@
 #include <sys/mman.h>
 #include <sys/ioctl.h>
 #include <errno.h>
+#include <fcntl.h>         /* openat (vms_sys_openat) -- vms-706 */
+#include <sys/syscall.h>   /* SYS___futex (vms_sys_futex) -- vms-706 */
 
 /* ================================================================
  * Process
@@ -113,6 +115,35 @@ static inline int vms_sys_ioctl(int fd, unsigned long request, unsigned long arg
     return ioctl(fd, request, (void *)(unsigned long)arg);
 }
 
+/* vms-706: the freestanding buffered-I/O (vms_stdio.c) + futex (vms_futex.c)
+ * facilities. The VMS_O_ and VMS_FUTEX_ constants resolve to the NetBSD
+ * <fcntl.h> / <sys/futex.h> values (vms_types.h substrate-select) -- never a
+ * transcribed Linux number. */
+
+static inline int vms_sys_openat(int dirfd, const char *path, int flags,
+                                 vms_mode_t mode)
+{
+    /* NetBSD libc openat(2); flags is the VMS_O_* mask (== NetBSD O_*). */
+    return openat(dirfd, path, flags, (mode_t)mode);
+}
+
+static inline long vms_sys_futex(uint32_t *uaddr, int futex_op, uint32_t val,
+                                 const struct vms_timespec *timeout,
+                                 uint32_t *uaddr2, uint32_t val3)
+{
+    /* NetBSD ships no libc futex() wrapper -- the syscall is __futex
+     * (SYS___futex), a SEVEN-arg form that inserts `val2` before val3. Our ops
+     * (WAIT/WAKE/WAIT_BITSET) do not use val2, so it is 0. struct vms_timespec
+     * is layout-compatible with struct timespec on ILP32; cast explicitly. */
+    long r = syscall(SYS___futex, (int *)uaddr, futex_op, (int)val,
+                     (const struct timespec *)timeout, (int *)uaddr2,
+                     0 /* val2 */, (int)val3);
+    /* Fold errno into a raw negative-errno return: vms_futex.c's
+     * vms_condvar_timedwait tests `ret == -VMS_ETIMEDOUT`, so the libc
+     * -1/errno convention would break timeout detection. */
+    return (r < 0) ? -(long)errno : r;
+}
+
 /* ================================================================
  * Raw-return error helpers. On the raw-freestanding path a syscall returns
  * negative-errno; libc returns -1 and sets errno. These helpers exist so any

src/libvmssys/vms_types.h

@@ -640,24 +640,36 @@ struct vms_io_uring_params {
 /* ================================================================
  * Futex operations
  *
- * These are Linux futex(2) op numbers. They are deliberately NOT defined on the
- * NetBSD substrate (rd vms-30a, audit item 5.2): NetBSD has no Linux-compatible
- * futex ABI, the netbsd executive/lnm/mbx wait primitive is provided separately
- * (design 4.2), and vms_futex.c (their only consumer) is excluded from the
- * netbsd build set. Leaving Linux-numeric op values defined on NetBSD would be
- * exactly the hardcoded-Linux-constant-reaching-a-NetBSD-syscall hazard this
- * audit item exists to kill, so the whole block is Linux-only.
+ * futex(2) op numbers, substrate-selected like VMS_O_* above (vms-706). The op
+ * VALUES happen to match across Linux and NetBSD, but each substrate takes them
+ * from ITS OWN header so no transcribed magic number reaches the wrong syscall:
+ * Linux hardcodes the well-known futex(2) numbers; NetBSD aliases <sys/futex.h>
+ * FUTEX_*, and vms_sys_futex (arch/vax/vms_syscall_netbsd.h) issues __futex(2).
+ * (Supersedes the earlier "deferred, NetBSD-excluded" audit note, rd vms-30a
+ * item 5.2: vms_futex.c is no longer excluded from the netbsd build.)
  * ================================================================ */
 
-#if !defined(__NetBSD__)
+#if defined(__NetBSD__)
+#include <sys/futex.h>
+#define VMS_FUTEX_WAIT                 FUTEX_WAIT
+#define VMS_FUTEX_WAKE                 FUTEX_WAKE
+#define VMS_FUTEX_WAIT_PRIVATE         (FUTEX_WAIT | FUTEX_PRIVATE_FLAG)
+#define VMS_FUTEX_WAKE_PRIVATE         (FUTEX_WAKE | FUTEX_PRIVATE_FLAG)
+#define VMS_FUTEX_WAIT_BITSET          FUTEX_WAIT_BITSET
+#define VMS_FUTEX_WAIT_BITSET_PRIVATE  (FUTEX_WAIT_BITSET | FUTEX_PRIVATE_FLAG)
+#define VMS_FUTEX_BITSET_MATCH_ANY     FUTEX_BITSET_MATCH_ANY
+/* Prove the substrate-select took the NetBSD header value, not a stale copy. */
+_Static_assert(VMS_FUTEX_WAIT == FUTEX_WAIT, "VMS_FUTEX_WAIT must resolve to NetBSD FUTEX_WAIT");
+_Static_assert(VMS_FUTEX_WAIT_BITSET == FUTEX_WAIT_BITSET, "VMS_FUTEX_WAIT_BITSET must resolve to NetBSD FUTEX_WAIT_BITSET");
+#else
 #define VMS_FUTEX_WAIT          0
 #define VMS_FUTEX_WAKE          1
 #define VMS_FUTEX_WAIT_PRIVATE  (VMS_FUTEX_WAIT | 128)
 #define VMS_FUTEX_WAKE_PRIVATE  (VMS_FUTEX_WAKE | 128)
 #define VMS_FUTEX_WAIT_BITSET   9
 #define VMS_FUTEX_WAIT_BITSET_PRIVATE  (VMS_FUTEX_WAIT_BITSET | 128)
 #define VMS_FUTEX_BITSET_MATCH_ANY  0xFFFFFFFF
-#endif /* !__NetBSD__ */
+#endif /* __NetBSD__ */
 
 /* ================================================================
  * Auxiliary vector (from kernel ELF loader)