rom/exec/allocmem.c

   1 /*
   2     Copyright © 1995-2012, 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(if (SysBase->DebugAROSBase))
  87     D(bug("Call AllocMem (%d, %08x)\n", byteSize, requirements));
  88
  89     /* 0-sized allocation results in returning NULL (API guarantee) */
  90     if(!byteSize)
  91         return NULL;
  92
  93     /* Make room for safety walls around allocated block and an some more extra space
  94        for other interesting things, actually --> the size.
  95
  96        This all will look like this:
  97
  98        [MEMCHUNK_FOR_EXTRA_STUFF][BEFORE-MUNGWALL][<alloced-memory-for-user>][AFTER_MUNGWALL]
  99
 100        MEMCHUNK_FOR_EXTRA_STUFF is used (amongst other things) to save the original alloc
 101        size (byteSize) param. So it is possible in FreeMem to check, if freemem size
 102        matches allocmem size or not.
 103     */
 104     if (PrivExecBase(SysBase)->IntFlags & EXECF_MungWall)
 105         byteSize += MUNGWALL_TOTAL_SIZE;
 106
 107     cmhs.cmhs_CurNode                = (struct Node *)SysBase->ex_MemHandlers.mlh_Head;
 108     cmhs.cmhs_Data.memh_RequestSize  = byteSize;
 109     cmhs.cmhs_Data.memh_RequestFlags = requirements;
 110     cmhs.cmhs_Data.memh_Flags        = 0;
 111
 112     do
 113     {
 114         res = nommu_AllocMem(byteSize, requirements, &loc, SysBase);
 115     } while (res == NULL && checkMemHandlers(&cmhs, SysBase) == MEM_TRY_AGAIN);
 116
 117 #if ENABLE_RT
 118     RT_Add (RTT_MEMORY, res, origSize);
 119 #endif
 120
 121     res = MungWall_Build(res, NULL, origSize, requirements, &loc, SysBase);
 122
 123     /* Set DOS error if called from a process */
 124     if (res == NULL)
 125     {
 126         struct Process *process = (struct Process *)FindTask(NULL);
 127         if (process->pr_Task.tc_Node.ln_Type == NT_PROCESS)
 128             process->pr_Result2 = ERROR_NO_FREE_STORE;
 129     }
 130
 131 #if DEBUG
 132     if (SysBase->DebugAROSBase)
 133     bug("AllocMem result: 0x%p\n", res);
 134 #endif
 135     return res;
 136
 137     AROS_LIBFUNC_EXIT
 138
 139 } /* AllocMem */