reactos/lib/3rdparty/mingw/pseudo-reloc.c

   1 /**
   2  * This file has no copyright assigned and is placed in the Public Domain.
   3  * This file is part of the w64 mingw-runtime package.
   4  * No warranty is given; refer to the file DISCLAIMER within this package.
   5  */
   6
   7 #include <windows.h>
   8 #include <stdio.h>
   9 #include <stdlib.h>
  10 #include <memory.h>
  11
  12 extern char __RUNTIME_PSEUDO_RELOC_LIST__;
  13 extern char __RUNTIME_PSEUDO_RELOC_LIST_END__;
  14 extern char _image_base__;
  15
  16 typedef struct {
  17   DWORD addend;
  18   DWORD target;
  19 } runtime_pseudo_reloc_item_v1;
  20
  21 typedef struct {
  22   DWORD sym;
  23   DWORD target;
  24   DWORD flags;
  25 } runtime_pseudo_reloc_item_v2;
  26
  27 typedef struct {
  28         DWORD magic1;
  29         DWORD magic2;
  30         DWORD version;
  31 } runtime_pseudo_reloc_v2;
  32
  33 static void
  34 __write_memory (void *addr,const void *src,size_t len)
  35 {
  36   MEMORY_BASIC_INFORMATION b;
  37   DWORD oldprot;
  38   if (!len)
  39     return;
  40   if (!VirtualQuery (addr, &b, sizeof(b)))
  41     abort ();
  42   // Protect
  43   if (b.Protect != PAGE_EXECUTE_READWRITE && b.Protect != PAGE_READWRITE)
  44     VirtualProtect (b.BaseAddress, b.RegionSize, PAGE_EXECUTE_READWRITE,
  45                   &oldprot);
  46   memcpy (addr, src, len);
  47   if (b.Protect != PAGE_EXECUTE_READWRITE && b.Protect != PAGE_READWRITE)
  48     VirtualProtect (b.BaseAddress, b.RegionSize, oldprot, &oldprot);
  49 }
  50
  51 #define RP_VERSION_V1 0
  52 #define RP_VERSION_V2 1
  53
  54 static void
  55 do_pseudo_reloc (void* start,void *end,void *base)
  56 {
  57   ptrdiff_t addr_imp, reldata;
  58   ptrdiff_t reloc_target = (ptrdiff_t) ((char *)end - (char*)start);
  59   runtime_pseudo_reloc_v2 *v2_hdr = (runtime_pseudo_reloc_v2 *) start;
  60   runtime_pseudo_reloc_item_v2 *r;
  61
  62   if (reloc_target < 8)
  63     return;
  64   /* Check if this is old version pseudo relocation version.  */
  65   if (reloc_target >= 12
  66       && v2_hdr->magic1 == 0 && v2_hdr->magic2 == 0
  67       && v2_hdr->version == RP_VERSION_V1)
  68       v2_hdr++;
  69   if (v2_hdr->magic1 != 0 || v2_hdr->magic2 != 0)
  70     {
  71       runtime_pseudo_reloc_item_v1 *o;
  72       for (o = (runtime_pseudo_reloc_item_v1 *) v2_hdr; o < (runtime_pseudo_reloc_item_v1 *)end; o++)
  73         {
  74           DWORD newval;
  75           reloc_target = (ptrdiff_t) base + o->target;
  76           newval = (*((DWORD*) reloc_target)) + o->addend;
  77           __write_memory ((void *) reloc_target, &newval, sizeof(DWORD));
  78         }
  79       return;
  80     }
  81   /* Check if this is a known version.  */
  82   if (v2_hdr->version != RP_VERSION_V2)
  83     {
  84       fprintf (stderr, "pseudo_relocation protocol version %d is unknown to this runtime.\n",
  85                (int) v2_hdr->version);
  86       return;
  87     }
  88   /* Walk over header.  */
  89   r = (runtime_pseudo_reloc_item_v2 *) &v2_hdr[1];
  90
  91   for (; r < (runtime_pseudo_reloc_item_v2 *) end; r++)
  92     {
  93       reloc_target = (ptrdiff_t) base + r->target;
  94       addr_imp = (ptrdiff_t) base + r->sym;
  95       addr_imp = *((ptrdiff_t *) addr_imp);
  96
  97       switch ((r->flags&0xff))
  98         {
  99           case 8:
 100             reldata = (ptrdiff_t) (*((unsigned char *)reloc_target));
 101             if ((reldata&0x80) != 0)
 102               reldata |= ~((ptrdiff_t) 0xff);
 103             break;
 104           case 16:
 105             reldata = (ptrdiff_t) (*((unsigned short *)reloc_target));
 106             if ((reldata&0x8000) != 0)
 107               reldata |= ~((ptrdiff_t) 0xffff);
 108             break;
 109           case 32:
 110             reldata = (ptrdiff_t) (*((unsigned int *)reloc_target));
 111 #ifdef _WIN64
 112             if ((reldata&0x80000000) != 0)
 113               reldata |= ~((ptrdiff_t) 0xffffffff);
 114 #endif
 115             break;
 116 #ifdef _WIN64
 117           case 64:
 118             reldata = (ptrdiff_t) (*((unsigned long long *)reloc_target));
 119             break;
 120 #endif
 121           default:
 122             reldata=0;
 123             fprintf(stderr, "Unknown pseudo relocation bit size %d\n",(int) (r->flags & 0xff));
 124             break;
 125         }
 126       reldata -= ((ptrdiff_t) base + r->sym);
 127       reldata += addr_imp;
 128       switch ((r->flags & 0xff))
 129         {
 130          case 8:
 131            __write_memory ((void *) reloc_target, &reldata, 1);
 132            break;
 133          case 16:
 134            __write_memory ((void *) reloc_target, &reldata, 2);
 135            break;
 136          case 32:
 137            __write_memory ((void *) reloc_target, &reldata, 4);
 138            break;
 139 #ifdef _WIN64
 140          case 64:
 141            __write_memory ((void *) reloc_target, &reldata, 8);
 142            break;
 143 #endif
 144         }
 145     }
 146 }
 147
 148 void
 149 _pei386_runtime_relocator ()
 150 {
 151   static int was_init = 0;
 152   if (was_init)
 153     return;
 154   ++was_init;
 155   do_pseudo_reloc (&__RUNTIME_PSEUDO_RELOC_LIST__,&__RUNTIME_PSEUDO_RELOC_LIST_END__,&_image_base__);
 156 }