From 22495036a354e209a7f2085bdd2e1fc82895208b Mon Sep 17 00:00:00 2001
From: Richard Braun <rbraun@sceen.net>
Date: Sun, 24 Nov 2013 11:17:54 +0100
Subject: New RPC for thread destruction

A new call, thread_terminate_release, is added to support self
destruction in threading libraries.

* include/mach/gnumach.defs (thread_terminate_release): New
simpleroutine declaration.
* kern/thread.c: Include vm/vm_user.h and ipc/mach_port.h.
(thread_terminate_release): New function.
* kern/thread.h (thread_terminate_release): New prototype.
---
 include/mach/gnumach.defs | 26 ++++++++++++++++++++++++++
 kern/thread.c             | 24 ++++++++++++++++++++++++
 kern/thread.h             |  7 +++++++
 3 files changed, 57 insertions(+)

diff --git a/include/mach/gnumach.defs b/include/mach/gnumach.defs
index 7331334..12c4e99 100644
--- a/include/mach/gnumach.defs
+++ b/include/mach/gnumach.defs
@@ -37,3 +37,29 @@ type vm_cache_statistics_data_t = struct[11] of integer_t;
 routine vm_cache_statistics(
 		target_task	: vm_task_t;
 	out	vm_cache_stats	: vm_cache_statistics_data_t);
+
+/*
+ * Terminate a thread and release rights and memory.
+ *
+ * Intended to be used by threading libraries to provide a clean way for
+ * threads to terminate themselves. The resources a thread wouldn't be able
+ * to release without this call when terminating itself are its
+ * last reference to its kernel port, its reply port, and its stack.
+ *
+ * This call is semantically equivalent to :
+ *  - mach_port_deallocate(task, thread_name);
+ *  - if (reply_port != MACH_PORT_NULL)
+ *      mach_port_destroy(task, reply_port);
+ *  - if ((address != 0) || (size != 0))
+ *      vm_deallocate(task, address, size)
+ *  - thread_terminate(thread)
+ *
+ * Implemented as a simple routine so a reply port isn't required.
+ */
+simpleroutine thread_terminate_release(
+		thread		: thread_t;
+		task		: task_t;
+		thread_name	: mach_port_name_t;
+		reply_port	: mach_port_name_t;
+		address		: vm_address_t;
+		size		: vm_size_t);
diff --git a/kern/thread.c b/kern/thread.c
index eb8a8bb..67fd41e 100644
--- a/kern/thread.c
+++ b/kern/thread.c
@@ -57,9 +57,11 @@
 #include <kern/slab.h>
 #include <kern/mach_clock.h>
 #include <vm/vm_kern.h>
+#include <vm/vm_user.h>
 #include <ipc/ipc_kmsg.h>
 #include <ipc/ipc_port.h>
 #include <ipc/mach_msg.h>
+#include <ipc/mach_port.h>
 #include <machine/machspl.h>		/* for splsched */
 #include <machine/pcb.h>
 #include <machine/thread.h>		/* for MACHINE_STACK */
@@ -850,6 +852,28 @@ kern_return_t thread_terminate(
 	return KERN_SUCCESS;
 }
 
+kern_return_t thread_terminate_release(
+	thread_t thread,
+	task_t task,
+	mach_port_t thread_name,
+	mach_port_t reply_port,
+	vm_offset_t address,
+	vm_size_t size)
+{
+	if (task == NULL)
+		return KERN_INVALID_ARGUMENT;
+
+	mach_port_deallocate(task->itk_space, thread_name);
+
+	if (reply_port != MACH_PORT_NULL)
+		mach_port_destroy(task->itk_space, reply_port);
+
+	if ((address != 0) || (size != 0))
+		vm_deallocate(task->map, address, size);
+
+	return thread_terminate(thread);
+}
+
 /*
  *	thread_force_terminate:
  *
diff --git a/kern/thread.h b/kern/thread.h
index 3959dfc..beb2dbc 100644
--- a/kern/thread.h
+++ b/kern/thread.h
@@ -259,6 +259,13 @@ extern kern_return_t	thread_create(
 	thread_t	*child_thread);
 extern kern_return_t	thread_terminate(
 	thread_t	thread);
+extern kern_return_t	thread_terminate_release(
+	thread_t	thread,
+	task_t		task,
+	mach_port_t	thread_name,
+	mach_port_t	reply_port,
+	vm_offset_t	address,
+	vm_size_t	size);
 extern kern_return_t	thread_suspend(
 	thread_t	thread);
 extern kern_return_t	thread_resume(
-- 
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