proc: Hierarchical proc servers.

Previously, a Subhurd's tasks were shown as weird processes in the
Motherhurd.  This change connects the proc server in the Motherhurd
with the proc server in the Subhurd, embedding the Subhurd's process
hierarchy.  Subhurd's processes can now be inspected and debugged like
any other process.

* NEWS: Update.
* boot/boot.c (mach_msg_forward): New function.
(boot_demuxer): Forward messages arriving on the new task notification
port from the proc server, and forward them to the proc server inside
the Subhurd via the notification port.
* proc/info.c (S_proc_task2proc): Relay request for processes in a task
namespace to the Subhurd's proc server.
(S_proc_pid2proc): Likewise.
(S_proc_getprocargs): Likewise.
(S_proc_getprocenv): Likewise.
(S_proc_getprocinfo): Likewise.  Translate PIDs.
(S_proc_getloginid): Likewise.
(S_proc_getloginpids): Likewise.
* proc/mgt.c (namespace_is_subprocess): New function.
(namespace_translate_pids): Likewise.
* proc/msg.c (S_proc_getmsgport): Relay request for processes in a task
namespace to the Subhurd's proc server.
* proc/pgrp.c (S_proc_getsid): Likewise.  Translate PIDs.
(S_proc_getsessionpids): Likewise.
(S_proc_getsessionpgids): Likewise.
(S_proc_getpgrppids): Likewise.
* proc/proc.h (namespace_is_subprocess): New prototype.
(namespace_translate_pids): Likewise.

1 files changed, 54 insertions, 0 deletions

diff --git a/boot/boot.c b/boot/boot.c
index 950aedb9..13a19d28 100644
--- a/boot/boot.c
+++ b/boot/boot.c
@@ -196,12 +196,66 @@ mig_reply_setup (
 #undef OutP
 }
 
+error_t
+mach_msg_forward (mach_msg_header_t *inp,
+                  mach_port_t destination, mach_msg_type_name_t destination_type)
+{
+  /* Put the reply port back at the correct position, insert new
+     destination.  */
+  inp->msgh_local_port = inp->msgh_remote_port;
+  inp->msgh_remote_port = destination;
+  inp->msgh_bits =
+    MACH_MSGH_BITS (destination_type, MACH_MSGH_BITS_REMOTE (inp->msgh_bits))
+    | MACH_MSGH_BITS_OTHER (inp->msgh_bits);
+
+  /* A word about resources carried in complex messages.
+
+     "In a received message, msgt_deallocate is TRUE in type
+     descriptors for out-of-line memory".  Therefore, "[the
+     out-of-line memory] is implicitly deallocated from the sender
+     [when we resend the message], as if by vm_deallocate".
+
+     Similarly, rights in messages will be either
+     MACH_MSG_TYPE_PORT_SEND, MACH_MSG_TYPE_PORT_SEND_ONCE, or
+     MACH_MSG_TYPE_PORT_RECEIVE.  These types are aliases for,
+     respectively, MACH_MSG_TYPE_MOVE_SEND,
+     MACH_MSG_TYPE_MOVE_SEND_ONCE, and MACH_MSG_TYPE_MOVE_RECEIVE.
+     Therefore, the rights are moved when we resend the message.  */
+
+  return mach_msg (inp, MACH_SEND_MSG, inp->msgh_size,
+                   0, MACH_PORT_NULL, MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
+}
+
 int
 boot_demuxer (mach_msg_header_t *inp,
 	      mach_msg_header_t *outp)
 {
+  error_t err;
   mig_routine_t routine;
   mig_reply_setup (inp, outp);
+
+  if (inp->msgh_local_port == task_notification_port
+      && MACH_PORT_VALID (new_task_notification)
+      && 24000 <= inp->msgh_id && inp->msgh_id < 24100)
+    {
+      /* This is a message of the Process subsystem.  We relay this to
+         allow the "outer" proc servers to communicate with the "inner"
+         one.  */
+      mig_reply_header_t *reply = (mig_reply_header_t *) outp;
+
+      if (MACH_PORT_VALID (new_task_notification))
+        err = mach_msg_forward (inp, new_task_notification, MACH_MSG_TYPE_COPY_SEND);
+      else
+        err = EOPNOTSUPP;
+
+      if (err)
+        reply->RetCode = err;
+      else
+        reply->RetCode = MIG_NO_REPLY;
+
+      return TRUE;
+    }
+
   if ((routine = io_server_routine (inp)) ||
       (routine = device_server_routine (inp)) ||
       (routine = notify_server_routine (inp)) ||