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, 56 insertions, 0 deletions

diff --git a/proc/mgt.c b/proc/mgt.c
index 87a7c96b..a9015ccc 100644
--- a/proc/mgt.c
+++ b/proc/mgt.c
@@ -732,7 +732,61 @@ new_proc (task_t task)
     complete_proc (p, genpid ());
   return p;
 }
+
 
+
+/* Task namespace support.  */
+
+/* Check if a given process is part of a task namespace but is not the
+   root.  The root is managed by us, while all other tasks are managed
+   by the root itself.  */
+int
+namespace_is_subprocess (struct proc *p)
+{
+  return (p
+          && MACH_PORT_VALID (p->p_task_namespace)
+          && p->p_parent
+          && MACH_PORT_VALID (p->p_parent->p_task_namespace));
+}
+
+/* Translate PIDs valid in NAMESPACE into PIDs valid in our own
+   process space.
+
+   Conditions: global_lock is unlocked before calling, and is locked
+   afterwards.  */
+error_t
+namespace_translate_pids (mach_port_t namespace, pid_t *pids, size_t pids_len)
+{
+  size_t i;
+  task_t *tasks;
+
+  tasks = calloc (pids_len, sizeof *tasks);
+  if (tasks == NULL)
+    {
+      pthread_mutex_lock (&global_lock);
+      return ENOMEM;
+    }
+
+  for (i = 0; i < pids_len; i++)
+    /* We handle errors by checking each returned task.  */
+    proc_pid2task (namespace, pids[i], &tasks[i]);
+
+  pthread_mutex_lock (&global_lock);
+
+  for (i = 0; i < pids_len; i++)
+    if (MACH_PORT_VALID (tasks[i]))
+      {
+        struct proc *p = task_find_nocreate (tasks[i]);
+        mach_port_deallocate (mach_task_self (), tasks[i]);
+        pids[i] = p ? p->p_pid : (pid_t) -1;
+      }
+    else
+      pids[i] = (pid_t) -1;
+
+  free (tasks);
+  return 0;
+}
+
 /* Find the creator of the task namespace that P is in.  */
 struct proc *
 namespace_find_root (struct proc *p)
@@ -759,6 +813,8 @@ namespace_terminate (struct proc *p, void *cookie)
     task_terminate (p->p_task);
 }
 
+
+
 /* The task associated with process P has died.  Drop most state,
    and then record us as dead.  Our parent will eventually complete the
    deallocation. */