rom/exec/allocmem.c

   1 /*
   2     Copyright © 1995-2011, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Allocate some memory
   6     Lang: english
   7 */
   8 #include <exec/alerts.h>
   9 #include <exec/execbase.h>
  10 #include <aros/libcall.h>
  11 #include <aros/asmcall.h>
  12 #include <aros/rt.h>
  13 #include <aros/macros.h>
  14 #include <aros/arossupportbase.h>
  15 #include <exec/memory.h>
  16 #include <exec/memheaderext.h>
  17 #include <exec/nodes.h>
  18 #include <dos/dos.h>
  19 #include <dos/dosextens.h>
  20 #include <proto/exec.h>
  21
  22 #include "exec_debug.h"
  23
  24 #ifndef DEBUG_AllocMem
  25 #   define DEBUG_AllocMem 0
  26 #endif
  27 #undef DEBUG
  28 #if DEBUG_AllocMem
  29 #   define DEBUG 1
  30 #endif
  31
  32 #include "exec_intern.h"
  33 #include "memory.h"
  34 #include "mungwall.h"
  35
  36 /*****************************************************************************
  37
  38     NAME */
  39
  40         AROS_LH2(APTR, AllocMem,
  41
  42 /*  SYNOPSIS */
  43         AROS_LHA(ULONG, byteSize,     D0),
  44         AROS_LHA(ULONG, requirements, D1),
  45
  46 /* LOCATION */
  47         struct ExecBase *, SysBase, 33, Exec)
  48
  49 /*  FUNCTION
  50         Allocate some memory from the sytem memory pool with the given
  51         requirements.
  52
  53     INPUTS
  54         byteSize     - Number of bytes you want to get
  55         requirements - Type of memory
  56
  57     RESULT
  58         A pointer to the number of bytes you wanted or NULL if the memory
  59         couldn't be allocated
  60
  61     NOTES
  62         The memory is aligned to sizeof(struct MemChunk). All requests
  63         are rounded up to a multiple of that size.
  64
  65     EXAMPLE
  66         mytask=(struct Task *)AllocMem(sizeof(struct Task),MEMF_PUBLIC|MEMF_CLEAR);
  67
  68     BUGS
  69
  70     SEE ALSO
  71         FreeMem()
  72
  73     INTERNALS
  74
  75 ******************************************************************************/
  76 {
  77     AROS_LIBFUNC_INIT
  78
  79     APTR res = NULL;
  80     struct checkMemHandlersState cmhs;
  81     ULONG origSize         = byteSize;
  82
  83     D(if (SysBase->DebugAROSBase))
  84     D(bug("Call AllocMem (%d, %08x)\n", byteSize, requirements));
  85
  86     /* Zero bytes requested? May return everything ;-). */
  87     if(!byteSize)
  88         return NULL;
  89
  90     /* Make room for safety walls around allocated block and an some more extra space
  91        for other interesting things, actually --> the size.
  92
  93        This all will look like this:
  94
  95        [MEMCHUNK_FOR_EXTRA_STUFF][BEFORE-MUNGWALL][<alloced-memory-for-user>][AFTER_MUNGWALL]
  96
  97        MEMCHUNK_FOR_EXTRA_STUFF is used (amongst other things) to save the original alloc
  98        size (byteSize) param. So it is possible in FreeMem to check, if freemem size
  99        matches allocmem size or not.
 100     */
 101     if (PrivExecBase(SysBase)->IntFlags & EXECF_MungWall)
 102         byteSize += MUNGWALL_TOTAL_SIZE;
 103
 104     cmhs.cmhs_CurNode                = (struct Node *)SysBase->ex_MemHandlers.mlh_Head;
 105     cmhs.cmhs_Data.memh_RequestSize  = byteSize;
 106     cmhs.cmhs_Data.memh_RequestFlags = requirements;
 107     cmhs.cmhs_Data.memh_Flags        = 0;
 108
 109     do
 110     {
 111         res = nommu_AllocMem(byteSize, requirements, SysBase);
 112     } while (res == NULL && checkMemHandlers(&cmhs, SysBase) == MEM_TRY_AGAIN);
 113
 114 #if ENABLE_RT
 115     RT_Add (RTT_MEMORY, res, origSize);
 116 #endif
 117
 118     res = MungWall_Build(res, NULL, origSize, requirements, "AllocMem", __builtin_return_address(0), SysBase);
 119
 120     /* Set DOS error if called from a process */
 121     if (res == NULL)
 122     {
 123         struct Process *process = (struct Process *)FindTask(NULL);
 124         if (process->pr_Task.tc_Node.ln_Type == NT_PROCESS)
 125             process->pr_Result2 = ERROR_NO_FREE_STORE;
 126     }
 127
 128 #if DEBUG
 129     if (SysBase->DebugAROSBase)
 130         bug("AllocMem result: 0x%p\n", res);
 131 #endif
 132     return res;
 133
 134     AROS_LIBFUNC_EXIT
 135
 136 } /* AllocMem */