Re: [PATCH 1/2] add separate port_size and mach_port_name_size definitions

[Samuel Thibault]

Luca Dariz, le dim. 03 avril 2022 17:00:19 +0200, a ecrit:
> * 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>

Applied, thanks!

> ---
>  cpu.sym  |  4 ++++
>  global.c |  4 ++++
>  global.h |  3 +++
>  lexxer.l | 24 ++++++++++++------------
>  parser.y |  7 +++++++
>  type.c   | 10 +++++-----
>  6 files changed, 35 insertions(+), 17 deletions(-)
> 
> diff --git a/cpu.sym b/cpu.sym
> index fcf6241..5e34074 100644
> --- a/cpu.sym
> +++ b/cpu.sym
> @@ -106,3 +106,7 @@ expr sizeof(double)                       sizeof_double
>  expr sizeof(mach_msg_header_t)               sizeof_mach_msg_header_t
>  expr sizeof(mach_msg_type_long_t)    sizeof_mach_msg_type_long_t
>  expr sizeof(mach_msg_type_t)         sizeof_mach_msg_type_t
> +expr sizeof(vm_offset_t)             vm_offset_size
> +expr (sizeof(vm_offset_t)*8)         vm_offset_size_in_bits
> +expr sizeof(mach_port_name_t)                port_name_size
> +expr (sizeof(mach_port_name_t)*8)    port_name_size_in_bits
> diff --git a/global.c b/global.c
> index 5685186..e2eb76e 100644
> --- a/global.c
> +++ b/global.c
> @@ -24,6 +24,7 @@
>   * rights to redistribute these changes.
>   */
>  
> +#include "cpu.h"
>  #include "error.h"
>  #include "global.h"
>  
> @@ -65,6 +66,9 @@ string_t InternalHeaderFileName = strNULL;
>  string_t UserFileName = strNULL;
>  string_t ServerFileName = strNULL;
>  
> +int port_size = port_name_size;
> +int port_size_in_bits = port_name_size_in_bits;
> +
>  void
>  more_global(void)
>  {
> diff --git a/global.h b/global.h
> index 8dbb6fd..cadd7e7 100644
> --- a/global.h
> +++ b/global.h
> @@ -67,6 +67,9 @@ extern string_t InternalHeaderFileName;
>  extern string_t UserFileName;
>  extern string_t ServerFileName;
>  
> +extern int port_size;
> +extern int port_size_in_bits;
> +
>  extern void more_global(void);
>  
>  #ifndef NULL
> diff --git a/lexxer.l b/lexxer.l
> index 48dda4a..71f43b2 100644
> --- a/lexxer.l
> +++ b/lexxer.l
> @@ -160,7 +160,7 @@ static void doSharp(const char *body); /* process body of 
> # directives */
>  <Normal>(?i:countinout)              FRETURN(flCountInOut);
>  <Normal>(?i:retcode)         FRETURN(flNone);
>  
> -<Normal>(?i:polymorphic)     
> TRETURN(MACH_MSG_TYPE_POLYMORPHIC,word_size_in_bits);
> +<Normal>(?i:polymorphic)     
> TRETURN(MACH_MSG_TYPE_POLYMORPHIC,port_size_in_bits);
>  
>  <Normal>"MACH_MSG_TYPE_UNSTRUCTURED" TRETURN(MACH_MSG_TYPE_UNSTRUCTURED,0);
>  <Normal>"MACH_MSG_TYPE_BIT"          TRETURN(MACH_MSG_TYPE_BIT,1);
> @@ -175,17 +175,17 @@ static void doSharp(const char *body); /* process body 
> of # directives */
>  <Normal>"MACH_MSG_TYPE_STRING"               TRETURN(MACH_MSG_TYPE_STRING,0);
>  <Normal>"MACH_MSG_TYPE_STRING_C"     TRETURN(MACH_MSG_TYPE_STRING_C,0);
>  
> -<Normal>"MACH_MSG_TYPE_MOVE_RECEIVE" 
> TPRETURN(MACH_MSG_TYPE_MOVE_RECEIVE,MACH_MSG_TYPE_PORT_RECEIVE,word_size_in_bits);
> -<Normal>"MACH_MSG_TYPE_COPY_SEND"    
> TPRETURN(MACH_MSG_TYPE_COPY_SEND,MACH_MSG_TYPE_PORT_SEND,word_size_in_bits);
> -<Normal>"MACH_MSG_TYPE_MAKE_SEND"    
> TPRETURN(MACH_MSG_TYPE_MAKE_SEND,MACH_MSG_TYPE_PORT_SEND,word_size_in_bits);
> -<Normal>"MACH_MSG_TYPE_MOVE_SEND"    
> TPRETURN(MACH_MSG_TYPE_MOVE_SEND,MACH_MSG_TYPE_PORT_SEND,word_size_in_bits);
> -<Normal>"MACH_MSG_TYPE_MAKE_SEND_ONCE"       
> TPRETURN(MACH_MSG_TYPE_MAKE_SEND_ONCE,MACH_MSG_TYPE_PORT_SEND_ONCE,word_size_in_bits);
> -<Normal>"MACH_MSG_TYPE_MOVE_SEND_ONCE"       
> TPRETURN(MACH_MSG_TYPE_MOVE_SEND_ONCE,MACH_MSG_TYPE_PORT_SEND_ONCE,word_size_in_bits);
> -
> -<Normal>"MACH_MSG_TYPE_PORT_NAME"    
> TRETURN(MACH_MSG_TYPE_PORT_NAME,word_size_in_bits);
> -<Normal>"MACH_MSG_TYPE_PORT_RECEIVE" 
> TPRETURN(MACH_MSG_TYPE_POLYMORPHIC,MACH_MSG_TYPE_PORT_RECEIVE,word_size_in_bits);
> -<Normal>"MACH_MSG_TYPE_PORT_SEND"    
> TPRETURN(MACH_MSG_TYPE_POLYMORPHIC,MACH_MSG_TYPE_PORT_SEND,word_size_in_bits);
> -<Normal>"MACH_MSG_TYPE_PORT_SEND_ONCE"       
> TPRETURN(MACH_MSG_TYPE_POLYMORPHIC,MACH_MSG_TYPE_PORT_SEND_ONCE,word_size_in_bits);
> +<Normal>"MACH_MSG_TYPE_MOVE_RECEIVE" 
> TPRETURN(MACH_MSG_TYPE_MOVE_RECEIVE,MACH_MSG_TYPE_PORT_RECEIVE,port_size_in_bits);
> +<Normal>"MACH_MSG_TYPE_COPY_SEND"    
> TPRETURN(MACH_MSG_TYPE_COPY_SEND,MACH_MSG_TYPE_PORT_SEND,port_size_in_bits);
> +<Normal>"MACH_MSG_TYPE_MAKE_SEND"    
> TPRETURN(MACH_MSG_TYPE_MAKE_SEND,MACH_MSG_TYPE_PORT_SEND,port_size_in_bits);
> +<Normal>"MACH_MSG_TYPE_MOVE_SEND"    
> TPRETURN(MACH_MSG_TYPE_MOVE_SEND,MACH_MSG_TYPE_PORT_SEND,port_size_in_bits);
> +<Normal>"MACH_MSG_TYPE_MAKE_SEND_ONCE"       
> TPRETURN(MACH_MSG_TYPE_MAKE_SEND_ONCE,MACH_MSG_TYPE_PORT_SEND_ONCE,port_size_in_bits);
> +<Normal>"MACH_MSG_TYPE_MOVE_SEND_ONCE"       
> TPRETURN(MACH_MSG_TYPE_MOVE_SEND_ONCE,MACH_MSG_TYPE_PORT_SEND_ONCE,port_size_in_bits);
> +
> +<Normal>"MACH_MSG_TYPE_PORT_NAME"    
> TRETURN(MACH_MSG_TYPE_PORT_NAME,port_name_size_in_bits);
> +<Normal>"MACH_MSG_TYPE_PORT_RECEIVE" 
> TPRETURN(MACH_MSG_TYPE_POLYMORPHIC,MACH_MSG_TYPE_PORT_RECEIVE,port_size_in_bits);
> +<Normal>"MACH_MSG_TYPE_PORT_SEND"    
> TPRETURN(MACH_MSG_TYPE_POLYMORPHIC,MACH_MSG_TYPE_PORT_SEND,port_size_in_bits);
> +<Normal>"MACH_MSG_TYPE_PORT_SEND_ONCE"       
> TPRETURN(MACH_MSG_TYPE_POLYMORPHIC,MACH_MSG_TYPE_PORT_SEND_ONCE,port_size_in_bits);
>  <Normal>"MACH_MSG_TYPE_POLYMORPHIC"  TRETURN(MACH_MSG_TYPE_POLYMORPHIC,0);
>  
>  <Normal>":"          RETURN(syColon);
> diff --git a/parser.y b/parser.y
> index 8c2190b..8d6b2aa 100644
> --- a/parser.y
> +++ b/parser.y
> @@ -116,6 +116,7 @@
>  
>  #include <stdio.h>
>  
> +#include "cpu.h"
>  #include "error.h"
>  #include "lexxer.h"
>  #include "global.h"
> @@ -223,12 +224,18 @@ SubsystemMod            :       syKernelUser
>      if (IsKernelUser)
>       warn("duplicate KernelUser keyword");
>      IsKernelUser = TRUE;
> +    port_size = vm_offset_size;
> +    port_size_in_bits = vm_offset_size_in_bits;
> +    init_type();
>  }
>                       |       syKernelServer
>  {
>      if (IsKernelServer)
>       warn("duplicate KernelServer keyword");
>      IsKernelServer = TRUE;
> +    port_size = vm_offset_size;
> +    port_size_in_bits = vm_offset_size_in_bits;
> +    init_type();
>  }
>                       ;
>  
> 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 ||
> -- 
> 2.30.2
> 
> 

-- 
Samuel
---
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