Re: Write System Pointer to User Space

Hi Peter,

Here's a pgm that does that.  The "memcpy" function does the equivalent
of a CPYBWP (Copy Bytes With Pointers) MI instruction under the covers.

Note that pointers have to be on 16-byte boundaries.  If you declare
them as pointers in your structure (not as a string or something else)
the C compiler will align them properly, even with "_Packed".

--Dave


/*----------------------------------------------*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <milib.h>
#include <mih/rslvsp>
#include <mih/setsppfp>

typedef _Packed struct {
    int               anInt;
   _SYSPTR            aSyp;
    char              aStr[9];
  } struc_t;

/*----------------------------------------------*/
void main(int argc, char **argv)
{
   _SYSPTR             spcSyp;
   _SPCPTR             spcSpp;
   _RSLV_Template_T    rslvTmplt;
    struc_t            struc;

   /*  Get a space ptr to the *usrspc  */

   rslvTmplt.Obj.Type_Subtype = _Usrspc;
   memset(rslvTmplt.Obj.Name, ' ', sizeof(rslvTmplt.Obj.Name));
   memcpy(rslvTmplt.Obj.Name, "AUSRSPC", 7);
   rslvTmplt.Auth = _AUTH_RETRIEVE;
   _RSLVSP2(&spcSyp, &rslvTmplt);
   spcSpp = _SETSPPFP(spcSyp);

   /*  Get a system ptr to a *pgm  */

   rslvTmplt.Obj.Type_Subtype = _Program;
   memset(rslvTmplt.Obj.Name, ' ', sizeof(rslvTmplt.Obj.Name));
   memcpy(rslvTmplt.Obj.Name, "APGM", 4);
   rslvTmplt.Auth = _AUTH_RETRIEVE;
   _RSLVSP2(&struc.aSyp, &rslvTmplt);

   memcpy(struc.aStr, "some data", 9);
   struc.anInt = 42;

   /*  Copy the structure (with the pointer) to the *usrspc  */

   memcpy(spcSpp, &struc, sizeof(struc));

   return;
}


Peter Daransky wrote:
> Hi,
> I try to write resolved system pointer of one object to user space ... 
> But it doesn't work for me!? Better sayed i've a C structure with many
> variables and my wish is write it complet as a block of data to user
> space, so that i can later read it with the resolved pointer ... 
> Do i need perform something special (API or MI instruction ...) ? 
> Has someone done something similar ? 
> A little example in C will be help :-) 
>  
> Thank you 
> peter_
>

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