[PATCH 06/16] hurd: add proc_mark_important

[Justus Winter]

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.

* hurd/process.defs (proc_mark_important): New routine definitions.
* hurd/process_reply.defs (proc_mark_important_request): Likewise.
* hurd/process_request.defs (proc_mark_important_request): Likewise.
---
 hurd/process.defs         |   11 ++++++++++-
 hurd/process_reply.defs   |    9 ++++++++-
 hurd/process_request.defs |   12 +++++++++++-
 3 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/hurd/process.defs b/hurd/process.defs
index 95d63f5..055ad72 100644
--- a/hurd/process.defs
+++ b/hurd/process.defs
@@ -1,5 +1,5 @@
 /* Definitions for process server interface
-   Copyright (C) 1992,93,94,95,96,97,2001 Free Software Foundation
+   Copyright (C) 1992,93,94,95,96,97,2001,2013 Free Software Foundation
 
 This file is part of the GNU Hurd.
 
@@ -378,3 +378,12 @@ routine proc_getnports (
 routine proc_set_init_task (
        process: process_t;
        task: task_t);
+
+/* Inform the process server that the process is important.  */
+routine proc_mark_important (
+       process: process_t);
+
+/* Query whether the process is important.  */
+routine proc_is_important (
+       process: process_t;
+       out essential: boolean_t);
diff --git a/hurd/process_reply.defs b/hurd/process_reply.defs
index 3a946c7..6f208eb 100644
--- a/hurd/process_reply.defs
+++ b/hurd/process_reply.defs
@@ -1,5 +1,5 @@
 /* Reply half of wait
-   Copyright (C) 1991,93,94,96,2001 Free Software Foundation, Inc.
+   Copyright (C) 1991,93,94,96,2001,13 Free Software Foundation, Inc.
 
 This file is part of the GNU Hurd.
 
@@ -176,3 +176,10 @@ simpleroutine proc_getnports (
        nports: mach_msg_type_number_t);
 
 skip; /* proc_set_init_task */
+skip; /* proc_mark_important */
+
+simpleroutine proc_is_important (
+       reply_port: reply_port_t;
+       RETURN_CODE_ARG;
+       essential: boolean_t);
+
diff --git a/hurd/process_request.defs b/hurd/process_request.defs
index 5b87166..5493fbc 100644
--- a/hurd/process_request.defs
+++ b/hurd/process_request.defs
@@ -1,6 +1,6 @@
 /* Definitions for process server interface (request-only version)
 
-   Copyright (C) 1992, 93, 94, 95, 96, 98 Free Software Foundation, Inc.
+   Copyright (C) 1992, 93, 94, 95, 96, 98, 2013 Free Software Foundation, Inc.
 
 This file is part of the GNU Hurd.
 
@@ -380,3 +380,13 @@ simpleroutine proc_set_init_task_request (
        process: process_t;
        ureplyport reply: reply_port_t;
        task: task_t);
+
+/* Inform the process server that the process is important.  */
+simpleroutine proc_mark_important_request (
+       process: process_t;
+       ureplyport reply: reply_port_t);
+
+/* Query whether the process is important.  */
+simpleroutine proc_is_important_request (
+       process: process_t;
+       ureplyport reply: reply_port_t);
-- 
1.7.10.4