# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1677949211 -3600
# Node ID a86fe04c6e2e756e719eb09922828b649198a9fe
# Parent  406b46fcc62fbabd68e065c32bc1b837c482ad1c
Allocate payload and stack resources dynamically to permit control over when
such resources may be released.

diff -r 406b46fcc62f -r a86fe04c6e2e libexec/include/exec/process_creating.h
--- a/libexec/include/exec/process_creating.h	Sat Mar 04 12:42:09 2023 +0100
+++ b/libexec/include/exec/process_creating.h	Sat Mar 04 18:00:11 2023 +0100
@@ -46,10 +46,10 @@
 
   /* Stack and payload descriptions. */
 
-  ExplicitSegment _rm_stack;
+  ExplicitSegment *_rm_stack = NULL;
   Payload *_rm_payload = NULL;
 
-  ExplicitSegment _program_stack;
+  ExplicitSegment *_program_stack = NULL;
   Payload *_program_payload = NULL;
 
   /* IPC gate for communication within the created task, plus allocated
diff -r 406b46fcc62f -r a86fe04c6e2e libexec/lib/src/process_creating.cc
--- a/libexec/lib/src/process_creating.cc	Sat Mar 04 12:42:09 2023 +0100
+++ b/libexec/lib/src/process_creating.cc	Sat Mar 04 18:00:11 2023 +0100
@@ -40,10 +40,10 @@
 /* Initialise the process creator with the details of a region mapper. */
 
 ProcessCreating::ProcessCreating(const char *rm_filename)
-: _rm_filename(rm_filename),
-  _rm_stack(Utcb_area_start - initial_stack_size, initial_stack_size, L4_FPAGE_RW),
-  _program_stack(Utcb_area_start - initial_stack_size * 2, initial_stack_size, L4_FPAGE_RW)
+: _rm_filename(rm_filename)
 {
+  _rm_stack = new ExplicitSegment(Utcb_area_start - initial_stack_size, initial_stack_size, L4_FPAGE_RW);
+  _program_stack = new ExplicitSegment(Utcb_area_start - initial_stack_size * 2, initial_stack_size, L4_FPAGE_RW);
 }
 
 /* Initialise the memory segments of the region mapper. These are mapped into
@@ -57,7 +57,7 @@
   if (err)
     return err;
 
-  return _rm_stack.allocate(true);
+  return _rm_stack->allocate(true);
 }
 
 /* Initialise the memory segments of the actual program. These are not mapped
@@ -71,7 +71,7 @@
   if (err)
     return err;
 
-  return _program_stack.allocate(true);
+  return _program_stack->allocate(true);
 }
 
 /* Initialise an external system-level pager serving the region mapper in a
@@ -93,7 +93,7 @@
 
   /* Include the region mapper's stack region. */
 
-  _exec_pager->add(_rm_stack.region());
+  _exec_pager->add(_rm_stack->region());
 
   /* Start the pager in a separate thread. */
 
@@ -181,7 +181,7 @@
 
   /* Introduce the stack region and capability. */
 
-  init_region(rm_regions, rm_mapped_caps, _program_stack.exec_region(), rm_index);
+  init_region(rm_regions, rm_mapped_caps, _program_stack->exec_region(), rm_index);
 
   /* Terminate the region array. */
 
@@ -221,7 +221,7 @@
      region mapper, plus the initial server capability and region details. */
 
   const char *argv[] = {_rm_filename};
-  Stack rm_st(_rm_stack);
+  Stack rm_st(*_rm_stack);
 
   rm_st.set_init_caps(rm_init_caps);
   rm_st.set_regions(rm_regions);
@@ -260,7 +260,7 @@
      actual program. The server capability should be assigned to the region
      mapper capability slot already. */
 
-  Stack program_st(_program_stack);
+  Stack program_st(*_program_stack);
 
   program_st.populate(argc, argv, envp);
 
@@ -318,12 +318,15 @@
   _exec_pager->set_task(_process.get_task());
   _exec_pager->set_gate(_ipc_gate);
 
-  /* Discard instances created to initialise the process.
+  /* Discard instances created to initialise the process. The region mapper
+     relies on resources associated with its payload and stack and so these
+     cannot be deleted immediately.
+
      NOTE: The region mapper payload could be retained instead of being
            reconstructed each time. */
 
-  delete _rm_payload;
   delete _program_payload;
+  delete _program_stack;
 
   return L4_EOK;
 }