gbhub: control socket + gbtype to inject shell input without the OSK

Typing into a Game Boy meant driving the on-screen keyboard by hand. But
the link port already *is* the shell's console: bytes the hub sends
un-SLIP-framed land straight on stdin (that's what GB.type() has always
done for spawn-mode command scripting). This just exposes it.

gbhub now serves a control socket (/tmp/gbhub.ctl, world-connectable like
the join socket) accepting two commands: 'list' and 'type [idx]' followed
by a payload (delimited by the client's half-close). Injection is chunked
and paced to respect the 64-byte kernel console ring, so arbitrarily long
input - even multi-line scripts - reaches the shell without overflow. The
server runs in both daemon and spawn modes.

tools/gbtype is the client:
  tools/gbtype 'ls -l'        run a command on GB0 (Enter appended)
  tools/gbtype -g 1 ps        target the Nth joined Game Boy
  tools/gbtype -n abc         no trailing Enter
  tools/gbtype -r             just press Enter
  tools/gbtype -l             list connected Game Boys
  printf 'ls\nuname\n' | tools/gbtype    pipe a script via stdin

Options precede the command; the first non-option word starts literal
text, so 'gbtype ls -l' needs no quoting. No root required.

Verified end to end: injected list/uname/echo through the real CTL
protocol and saw the shell execute each and echo output back.

1 files changed, 74 insertions, 3 deletions

diff --git a/tools/gbhub b/tools/gbhub
index 85a4843..21ee19b 100755
--- a/tools/gbhub
+++ b/tools/gbhub
@@ -22,6 +22,7 @@ HOME = os.path.expanduser("~" + (os.environ.get("SUDO_USER") or ""))
 EMU  = os.path.join(HOME, "dev/gbc/build/sl0pboy")
 ROM  = os.path.join(HOME, "dev/gbos/gbos.gb")
 SOCK = "/tmp/gbhub.sock"
+CTL  = "/tmp/gbhub.ctl"    # control socket: external shell-input injection (gbtype)
 IFACE, GW, MTU = "gbtun0", b"\x0a\x00\x00\x01", 320
 END, ESC, BCAST = 0xC0, 0xDB, b"\xff\xff\xff\xff"
 
@@ -142,8 +143,9 @@ def net_setup():
     def cleanup():
         sh("iptables -t nat -D POSTROUTING -s 10.0.0.0/24 -o %s -j MASQUERADE" % wan)
         sh("iptables -D FORWARD -i %s -j ACCEPT" % IFACE); sh("iptables -D FORWARD -o %s -j ACCEPT" % IFACE)
-        try: os.unlink(SOCK)
-        except Exception: pass
+        for p in (SOCK, CTL):
+            try: os.unlink(p)
+            except Exception: pass
     atexit.register(cleanup)
     return wan
 
@@ -157,6 +159,73 @@ def register(conn):
                      % (time.strftime("%H:%M:%S"), gb.idx, octet))
     return gb
 
+# -----------------------------------------------------------------------------
+# Control socket: inject shell input into a GB from the host (see tools/gbtype).
+# The link port is the GB's console when nothing SLIP-frames the bytes, so text
+# written with GB.type() lands on the shell's stdin - the OSK, remotely.
+# -----------------------------------------------------------------------------
+def _find_gb(idx):
+    gbs = sorted(conns.values(), key=lambda g: g.idx)
+    if not gbs: return None
+    if idx is None: return gbs[0]                       # default: lowest-index GB
+    for g in gbs:
+        if g.idx == idx: return g
+    return None
+
+def _type_paced(gb, data):
+    # The kernel console ring is 64 bytes and one net_pump drains a whole burst
+    # into it at once, so feed in small chunks with a brief gap - the shell
+    # keeps up easily, and arbitrarily long scripts inject without overflow.
+    for i in range(0, len(data), 32):
+        gb.send(data[i:i+32]); time.sleep(0.04)
+
+def _control_client(conn):
+    try:
+        conn.settimeout(5)
+        data = b""
+        while True:                                     # read header + payload
+            try: d = conn.recv(4096)                     # until the client
+            except Exception: break                      # half-closes (SHUT_WR)
+            if not d: break
+            data += d
+        head, _, payload = data.partition(b"\n")
+        parts = head.decode(errors="replace").split()
+        cmd = parts[0].lower() if parts else ""
+        if cmd == "list":
+            gbs = sorted(conns.values(), key=lambda g: g.idx)
+            msg = "".join("GB%d  10.0.0.%d\n" % (g.idx, g.octet) for g in gbs)
+            conn.sendall(msg.encode() or b"(no Game Boys connected)\n")
+        elif cmd == "type":
+            idx = None
+            if len(parts) >= 2:
+                try: idx = int(parts[1])
+                except ValueError: idx = None
+            gb = _find_gb(idx)
+            if gb is None:
+                conn.sendall(b"err: no such Game Boy (try 'list')\n")
+            else:
+                _type_paced(gb, payload)
+                conn.sendall(("ok: %d bytes -> GB%d\n" % (len(payload), gb.idx)).encode())
+        else:
+            conn.sendall(b"err: commands are 'type [idx]' (payload follows newline) or 'list'\n")
+    except Exception:
+        pass
+    finally:
+        try: conn.close()
+        except Exception: pass
+
+def control_server():
+    try: os.unlink(CTL)
+    except Exception: pass
+    c = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
+    c.bind(CTL); c.listen(8)
+    try: os.chmod(CTL, 0o777)                            # let non-root gbtype connect
+    except Exception: pass
+    while True:
+        try: conn, _ = c.accept()
+        except Exception: return
+        threading.Thread(target=_control_client, args=(conn,), daemon=True).start()
+
 def main():
     if os.geteuid() != 0: sys.exit("gbhub: run as root")
     args = sys.argv[1:]
@@ -166,11 +235,13 @@ def main():
     except Exception: pass
     srv = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM); srv.bind(SOCK); srv.listen(8)
     threading.Thread(target=tun_reader, daemon=True).start()
+    threading.Thread(target=control_server, daemon=True).start()   # gbtype input
 
     if daemon:
         os.chmod(SOCK, 0o777)                            # let non-root gbjoin connect
         sys.stderr.write("[gbhub] up on 10.0.0.0/24, NAT via %s. "
-                         "join Game Boys in other terminals:  tools/gbjoin\n" % wan)
+                         "join Game Boys in other terminals:  tools/gbjoin\n"
+                         "[gbhub] inject shell input without the OSK:  tools/gbtype 'ls'\n" % wan)
         try:
             while True:
                 conn, _ = srv.accept(); register(conn)