add separate port_size and mach_port_name_size definitions

* cpu.sym: retrieve size of vm_offset_t and mach_port_name_t from
  gnumach headers at compile type.
* global.{c,h}: add port size as a variable and initialize it to the
  port name size.
* lexxer.l: apply port or port name size to the corresponding types,
  instead of using the word size.
* parser.y: update port size if we're generating for kernel-space
  (server or client). Also re-initialize default port types to account
  for this change.
* type.c: use port size instead of word size in default port types and
  runtime checks.

There are many assumptions about mach_port_t:
 - on kernel side, its size is the same as a pointer. This allows to
   replace the port name with the address of the corresponding data
   structure during copyin in mach_msg()
 - in mig, this is also the "word size", which is derived from gnumach
   headers as the size of integer_t
 - its size is also the same as natural_t, so it's possible to model
   structures like mach_port_status_t as an array of integer_t in
   mig. This is convenient since arrays and structures can't have
   mixed types.
 - its size is always the same as the port name size

This patch does not change the current behaviour on 32-bit kernels,
but allows for some of these assumptions to be broken on 64-bit
kernels. This is needed to have 32-bit port names on 64-bit kernels
and be able to support a 32-bit userspace.  It still leaves the choice
for a 64-bit userspace, if all integer_t and natural_t are to be
extended to 64 bit.

However keeping 32-bit port names seems to be the right thing, based on
previous discussions [1], even for a 64-bit kernel.

The only assumption kept is that in kernel-space ports are always the
size of a pointer, as they refer to a data structure and not to a
specific port name.  To ensure this is true for various user/kernel
combinations, we dynamically change the port size if we're generating
code for kernel-space server or clients, and keep the size of a port the
same of a port name for user-space servers and clients.

[1] https://lists.gnu.org/archive/html/bug-hurd/2012-04/msg00000.html

Signed-off-by: Luca Dariz <luca@orpolo.org>
Message-Id: <20220403150020.120799-2-luca@orpolo.org>

1 files changed, 5 insertions, 5 deletions

diff --git a/type.c b/type.c
index eb88cf4..86137ae 100644
--- a/type.c
+++ b/type.c
@@ -848,7 +848,7 @@ init_type(void)
     itRequestPortType->itInNameStr = "MACH_MSG_TYPE_COPY_SEND";
     itRequestPortType->itOutName = MACH_MSG_TYPE_PORT_SEND;
     itRequestPortType->itOutNameStr = "MACH_MSG_TYPE_PORT_SEND";
-    itRequestPortType->itSize = word_size_in_bits;
+    itRequestPortType->itSize = port_size_in_bits;
     itCalculateSizeInfo(itRequestPortType);
     itCalculateNameInfo(itRequestPortType);
 
@@ -858,7 +858,7 @@ init_type(void)
     itZeroReplyPortType->itInNameStr = "0";
     itZeroReplyPortType->itOutName = 0;
     itZeroReplyPortType->itOutNameStr = "0";
-    itZeroReplyPortType->itSize = word_size_in_bits;
+    itZeroReplyPortType->itSize = port_size_in_bits;
     itCalculateSizeInfo(itZeroReplyPortType);
     itCalculateNameInfo(itZeroReplyPortType);
 
@@ -868,7 +868,7 @@ init_type(void)
     itRealReplyPortType->itInNameStr = "MACH_MSG_TYPE_MAKE_SEND_ONCE";
     itRealReplyPortType->itOutName = MACH_MSG_TYPE_PORT_SEND_ONCE;
     itRealReplyPortType->itOutNameStr = "MACH_MSG_TYPE_PORT_SEND_ONCE";
-    itRealReplyPortType->itSize = word_size_in_bits;
+    itRealReplyPortType->itSize = port_size_in_bits;
     itCalculateSizeInfo(itRealReplyPortType);
     itCalculateNameInfo(itRealReplyPortType);
 
@@ -906,7 +906,7 @@ itCheckRequestPortType(identifier_t name, const ipc_type_t *it)
 	 (it->itOutName != MACH_MSG_TYPE_PORT_SEND_ONCE) &&
 	 (it->itOutName != MACH_MSG_TYPE_POLYMORPHIC)) ||
 	(it->itNumber != 1) ||
-	(it->itSize != word_size_in_bits) ||
+	(it->itSize != port_size_in_bits) ||
 	!it->itInLine ||
 	it->itDeallocate != d_NO ||
 	!it->itStruct ||
@@ -927,7 +927,7 @@ itCheckReplyPortType(identifier_t name, const ipc_type_t *it)
 	 (it->itOutName != MACH_MSG_TYPE_POLYMORPHIC) &&
 	 (it->itOutName != 0)) ||
 	(it->itNumber != 1) ||
-	(it->itSize != word_size_in_bits) ||
+	(it->itSize != port_size_in_bits) ||
 	!it->itInLine ||
 	it->itDeallocate != d_NO ||
 	!it->itStruct ||