rom/exec/allocmem.c

   1 /*
   2     Copyright © 1995-2015, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Allocate some memory
   6     Lang: english
   7 */
   8
   9 #include <exec/alerts.h>
  10 #include <exec/execbase.h>
  11 #include <aros/libcall.h>
  12 #include <aros/asmcall.h>
  13 #include <aros/rt.h>
  14 #include <aros/macros.h>
  15 #include <aros/arossupportbase.h>
  16 #include <exec/memory.h>
  17 #include <exec/memheaderext.h>
  18 #include <exec/nodes.h>
  19 #include <dos/dos.h>
  20 #include <dos/dosextens.h>
  21 #include <proto/exec.h>
  22
  23 #include "exec_debug.h"
  24
  25 #ifndef DEBUG_AllocMem
  26 #   define DEBUG_AllocMem 0
  27 #endif
  28 #undef DEBUG
  29 #if DEBUG_AllocMem
  30 #   define DEBUG 1
  31 #endif
  32
  33 #include "exec_intern.h"
  34 #include "exec_util.h"
  35 #include "memory.h"
  36 #include "mungwall.h"
  37
  38 /*****************************************************************************
  39
  40     NAME */
  41
  42         AROS_LH2(APTR, AllocMem,
  43
  44 /*  SYNOPSIS */
  45         AROS_LHA(IPTR,  byteSize,     D0),
  46         AROS_LHA(ULONG, requirements, D1),
  47
  48 /* LOCATION */
  49         struct ExecBase *, SysBase, 33, Exec)
  50
  51 /*  FUNCTION
  52         Allocate some memory from the sytem memory pool with the given
  53         requirements.
  54
  55     INPUTS
  56         byteSize     - Number of bytes you want to get
  57         requirements - Type of memory
  58
  59     RESULT
  60         A pointer to the number of bytes you wanted or NULL if the memory
  61         couldn't be allocated
  62
  63     NOTES
  64         The memory is aligned to sizeof(struct MemChunk). All requests
  65         are rounded up to a multiple of that size.
  66
  67     EXAMPLE
  68         mytask=(struct Task *)AllocMem(sizeof(struct Task),MEMF_PUBLIC|MEMF_CLEAR);
  69
  70     BUGS
  71
  72     SEE ALSO
  73         FreeMem()
  74
  75     INTERNALS
  76
  77 ******************************************************************************/
  78 {
  79     AROS_LIBFUNC_INIT
  80
  81     APTR res = NULL;
  82     struct checkMemHandlersState cmhs;
  83     IPTR origSize = byteSize;
  84     struct TraceLocation loc = CURRENT_LOCATION("AllocMem");
  85
  86     D(
  87         if (SysBase->DebugAROSBase)
  88         {
  89             bug("Call AllocMem (%d, %08x)\n", byteSize, requirements);
  90         }
  91      )
  92
  93     /* 0-sized allocation results in returning NULL (API guarantee) */
  94     if(!byteSize)
  95         return NULL;
  96
  97     /* Make room for safety walls around allocated block and an some more extra space
  98        for other interesting things, actually --> the size.
  99
 100        This all will look like this:
 101
 102        [MEMCHUNK_FOR_EXTRA_STUFF][BEFORE-MUNGWALL][<alloced-memory-for-user>][AFTER_MUNGWALL]
 103
 104        MEMCHUNK_FOR_EXTRA_STUFF is used (amongst other things) to save the original alloc
 105        size (byteSize) param. So it is possible in FreeMem to check, if freemem size
 106        matches allocmem size or not.
 107     */
 108     if (PrivExecBase(SysBase)->IntFlags & EXECF_MungWall)
 109         byteSize += MUNGWALL_TOTAL_SIZE;
 110
 111     cmhs.cmhs_CurNode                = (struct Node *)SysBase->ex_MemHandlers.mlh_Head;
 112     cmhs.cmhs_Data.memh_RequestSize  = byteSize;
 113     cmhs.cmhs_Data.memh_RequestFlags = requirements;
 114     cmhs.cmhs_Data.memh_Flags        = 0;
 115
 116     do
 117     {
 118         res = nommu_AllocMem(byteSize, requirements, &loc, SysBase);
 119     } while (res == NULL && checkMemHandlers(&cmhs, SysBase) == MEM_TRY_AGAIN);
 120
 121 #if ENABLE_RT
 122     RT_Add (RTT_MEMORY, res, origSize);
 123 #endif
 124
 125     res = MungWall_Build(res, NULL, origSize, requirements, &loc, SysBase);
 126
 127     /* Set DOS error if called from a process */
 128     if (res == NULL)
 129     {
 130         struct Process *process = (struct Process *)GET_THIS_TASK;
 131         if (process && process->pr_Task.tc_Node.ln_Type == NT_PROCESS)
 132             process->pr_Result2 = ERROR_NO_FREE_STORE;
 133     }
 134
 135     D(
 136         if (SysBase->DebugAROSBase)
 137         {
 138             bug("AllocMem result: 0x%p\n", res);
 139         }
 140      )
 141     return res;
 142
 143     AROS_LIBFUNC_EXIT
 144
 145 } /* AllocMem */