rom/exec/sumlibrary.c

   1 /*
   2     Copyright © 1995-2001, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Build checksum for a library.
   6     Lang: english
   7 */
   8 #include <exec/execbase.h>
   9 #include <exec/alerts.h>
  10 #include <aros/libcall.h>
  11 #include <proto/exec.h>
  12
  13 /*****************************************************************************
  14
  15     NAME */
  16
  17         AROS_LH1(void, SumLibrary,
  18
  19 /*  SYNOPSIS */
  20         AROS_LHA(struct Library *, library,A1),
  21
  22 /*  LOCATION */
  23         struct ExecBase *, SysBase, 71, Exec)
  24
  25 /*  FUNCTION
  26         Builds the checksum over a given library's jumptable and either puts
  27         it into the library->lib_Sum field (if the library is marked as changed)
  28         or compares it with this field and Alert()s at mismatch.
  29
  30     INPUTS
  31         library - Pointer to library structure.
  32
  33     RESULT
  34
  35     NOTES
  36
  37     EXAMPLE
  38
  39     BUGS
  40
  41     SEE ALSO
  42         AddLibrary(), RemLibrary(), MakeLibrary(), MakeFunctions(), InitStruct()
  43
  44     INTERNALS
  45
  46 ******************************************************************************/
  47 {
  48     AROS_LIBFUNC_INIT
  49
  50     UBYTE oldflags;
  51     ULONG sum;
  52
  53     /* Arbitrate for library base */
  54     Forbid();
  55
  56     /*
  57         If the library checksumming is already in progress or if the
  58         checksum is unused skip this part
  59     */
  60     if(library->lib_Flags&LIBF_SUMUSED&&!(library->lib_Flags&LIBF_SUMMING))
  61     {
  62         /* As long as the library is marked as changed */
  63         do
  64         {
  65             ULONG *lp;
  66
  67             /* Memorize library flags */
  68             oldflags=library->lib_Flags;
  69
  70             /* Tell other tasks: Summing in progress */
  71             library->lib_Flags|=LIBF_SUMMING;
  72             library->lib_Flags&=~LIBF_CHANGED;
  73
  74             /* As long as the summing goes multitasking may be permitted. */
  75             Permit();
  76
  77             /* Build checksum. Note: library bases are LONG aligned */
  78             sum=0;
  79             /* Get start of jumptable */
  80             lp=(ULONG *)((UBYTE *)library+library->lib_NegSize);
  81             /* And sum it up */
  82             while(lp<(ULONG *)library)
  83                 sum+=*lp++;
  84
  85             /* Summing complete. Arbitrate again. */
  86             Forbid();
  87
  88             /* Remove summing flag */
  89             library->lib_Flags&=~LIBF_SUMMING;
  90
  91             /* Do it again if the library changed while summing. */
  92         }while(library->lib_Flags&LIBF_CHANGED);
  93
  94         /*
  95             Alert() if the library wasn't marked as changed and if the
  96             checksum mismatches.
  97         */
  98         if(!(oldflags&LIBF_CHANGED)&&library->lib_Sum!=sum)
  99             Alert(AT_DeadEnd|AN_LibChkSum);
 100
 101         /* Set new checksum */
 102         library->lib_Sum=sum;
 103     }
 104
 105     /* All done. */
 106     Permit();
 107     AROS_LIBFUNC_EXIT
 108 } /* SumLibrary */
 109