[hurd] 37/70: init: Mark all of inits children and init itself as important

[Samuel Thibault]

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sthibault pushed a commit to branch upstream
in repository hurd.

commit 580abff9c280ab91bb05b999f8ea2bda36a55e05
Author: Justus Winter <address@hidden>
Date:   Thu Aug 15 09:37:58 2013 +0200

    init: Mark all of inits children and init itself as important
    
    This is based on a fragment of Guillem Jovers patch presented here:
    
    http://lists.gnu.org/archive/html/bug-hurd/2006-02/msg00081.html
    
    It has been refreshed, updated and the copyright year is adjusted
    properly. It has been complemented with the necessary features to
    address the issues the original patch set out to address, namely
    that killall5 freezes the proc translator before it tries to walk
    over /proc/*/stat to decide which process to kill. Prior to this
    patch (and the one marking the procfs server as important
    process), killall5 would deadlock trying to walk over the proc
    file system.
    
    Ironically it would not have killed any process later on even if
    it had the chance, since two values obtained from /proc/*/stat
    are currently hardcoded to zero in our procfs. Patches addressing
    the problem as a whole are prepared and will be sent as a follow
    up.
    
    * init/init.c (launch_core_servers): Mark init, auth, proc and fs
      servers as important.
    (start_child): Mark the real init as important.
    (S_startup_important_task): Mark exec server as important.
---
 init/init.c |   21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/init/init.c b/init/init.c
index 05fce78..94f1a9b 100644
--- a/init/init.c
+++ b/init/init.c
@@ -1,7 +1,7 @@
 /* Start and maintain hurd core servers and system run state
 
    Copyright (C) 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002,
-     2005, 2008 Free Software Foundation, Inc.
+     2005, 2008, 2013 Free Software Foundation, Inc.
    This file is part of the GNU Hurd.
 
    The GNU Hurd is free software; you can redistribute it and/or modify
@@ -643,6 +643,8 @@ launch_core_servers (void)
       device_master = 0;
     }
 
+  /* Mark us as important.  */
+  proc_mark_important (procserver);
   proc_mark_exec (procserver);
 
   /* Declare that the filesystem and auth are our children. */
@@ -650,6 +652,7 @@ launch_core_servers (void)
   proc_child (procserver, authtask);
 
   proc_task2proc (procserver, authtask, &authproc);
+  proc_mark_important (authproc);
   proc_mark_exec (authproc);
   startup_authinit_reply (authreply, authreplytype, 0, authproc,
                          MACH_MSG_TYPE_COPY_SEND);
@@ -672,6 +675,7 @@ launch_core_servers (void)
   err = proc_task2proc (procserver, proctask, &procproc);
   if (!err)
     {
+      proc_mark_important (procproc);
       proc_mark_exec (procproc);
       mach_port_deallocate (mach_task_self (), procproc);
     }
@@ -681,6 +685,7 @@ launch_core_servers (void)
   /* Get the bootstrap filesystem's proc server port.
      We must do this before calling proc_setmsgport below.  */
   proc_task2proc (procserver, fstask, &fsproc);
+  proc_mark_important (fsproc);
   proc_mark_exec (fsproc);
 
 #if 0
@@ -785,8 +790,10 @@ frob_kernel_process (void)
       return;
     }
 
-  /* Mark the kernel task as an essential task so that we never
-     want to task_terminate it.  */
+  /* Mark the kernel task as an essential task so that we or the proc server
+     never want to task_terminate it.  */
+  proc_mark_important (proc);
+
   err = record_essential_task ("kernel", task);
   assert_perror (err);
 
@@ -1067,6 +1074,7 @@ start_child (const char *prog, char **progargs)
                   default_ports, MACH_MSG_TYPE_COPY_SEND, INIT_PORT_MAX,
                   default_ints, INIT_INT_MAX,
                   NULL, 0, NULL, 0);
+  proc_mark_important (default_ports[INIT_PORT_PROC]);
   mach_port_deallocate (mach_task_self (), default_ports[INIT_PORT_PROC]);
   mach_port_deallocate (mach_task_self (), file);
   if (err)
@@ -1207,7 +1215,12 @@ S_startup_essential_task (mach_port_t server,
       if (!strcmp (name, "auth"))
        authinit = 1;
       else if (!strcmp (name, "exec"))
-       execinit = 1;
+        {
+          execinit = 1;
+          mach_port_t execproc;
+          proc_task2proc (procserver, task, &execproc);
+          proc_mark_important (execproc);
+        }
       else if (!strcmp (name, "proc"))
        procinit = 1;
 

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