ms/uplink.c

   1 /*
   2  * Copyright 2004-2016 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the Apache License 2.0 (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 #if (defined(_WIN64) || defined(_WIN32_WCE)) && !defined(UNICODE)
  11 # define UNICODE
  12 #endif
  13 #if defined(UNICODE) && !defined(_UNICODE)
  14 # define _UNICODE
  15 #endif
  16 #if defined(_UNICODE) && !defined(UNICODE)
  17 # define UNICODE
  18 #endif
  19
  20 #include <windows.h>
  21 #include <tchar.h>
  22 #include <stdio.h>
  23 #include "uplink.h"
  24 void OPENSSL_showfatal(const char *, ...);
  25
  26 static TCHAR msg[128];
  27
  28 static void unimplemented(void)
  29 {
  30     OPENSSL_showfatal(sizeof(TCHAR) == sizeof(char) ? "%s\n" : "%S\n", msg);
  31     TerminateProcess(GetCurrentProcess(), 1);
  32 }
  33
  34 void OPENSSL_Uplink(volatile void **table, int index)
  35 {
  36     static HMODULE volatile apphandle = NULL;
  37     static void **volatile applinktable = NULL;
  38     int len;
  39     void (*func) (void) = unimplemented;
  40     HANDLE h;
  41     void **p;
  42
  43     /*
  44      * Note that the below code is not MT-safe in respect to msg buffer, but
  45      * what's the worst thing that can happen? Error message might be
  46      * misleading or corrupted. As error condition is fatal and should never
  47      * be risen, I accept the risk...
  48      */
  49     /*
  50      * One can argue that I should have used InterlockedExchangePointer or
  51      * something to update static variables and table[]. Well, store
  52      * instructions are as atomic as they can get and assigned values are
  53      * effectively constant... So that volatile qualifier should be
  54      * sufficient [it prohibits compiler to reorder memory access
  55      * instructions].
  56      */
  57     do {
  58         len = _sntprintf(msg, sizeof(msg) / sizeof(TCHAR),
  59                          _T("OPENSSL_Uplink(%p,%02X): "), table, index);
  60         _tcscpy(msg + len, _T("unimplemented function"));
  61
  62         if ((h = apphandle) == NULL) {
  63             if ((h = GetModuleHandle(NULL)) == NULL) {
  64                 apphandle = (HMODULE) - 1;
  65                 _tcscpy(msg + len, _T("no host application"));
  66                 break;
  67             }
  68             apphandle = h;
  69         }
  70         if ((h = apphandle) == (HMODULE) - 1) /* revalidate */
  71             break;
  72
  73         if (applinktable == NULL) {
  74             void **(*applink) ();
  75
  76             applink = (void **(*)())GetProcAddress(h, "OPENSSL_Applink");
  77             if (applink == NULL) {
  78                 apphandle = (HMODULE) - 1;
  79                 _tcscpy(msg + len, _T("no OPENSSL_Applink"));
  80                 break;
  81             }
  82             p = (*applink) ();
  83             if (p == NULL) {
  84                 apphandle = (HMODULE) - 1;
  85                 _tcscpy(msg + len, _T("no ApplinkTable"));
  86                 break;
  87             }
  88             applinktable = p;
  89         } else
  90             p = applinktable;
  91
  92         if (index > (int)p[0])
  93             break;
  94
  95         if (p[index])
  96             func = p[index];
  97     } while (0);
  98
  99     table[index] = func;
 100 }
 101
 102 #if defined(_MSC_VER) && defined(_M_IX86)
 103 # define LAZY(i)         \
 104 __declspec(naked) static void lazy##i (void) {  \
 105         _asm    push i                          \
 106         _asm    push OFFSET OPENSSL_UplinkTable \
 107         _asm    call OPENSSL_Uplink             \
 108         _asm    add  esp,8                      \
 109         _asm    jmp  OPENSSL_UplinkTable+4*i    }
 110
 111 # if APPLINK_MAX>25
 112 #  error "Add more stubs..."
 113 # endif
 114 /* make some in advance... */
 115 LAZY(1) LAZY(2) LAZY(3) LAZY(4) LAZY(5)
 116     LAZY(6) LAZY(7) LAZY(8) LAZY(9) LAZY(10)
 117     LAZY(11) LAZY(12) LAZY(13) LAZY(14) LAZY(15)
 118     LAZY(16) LAZY(17) LAZY(18) LAZY(19) LAZY(20)
 119     LAZY(21) LAZY(22) LAZY(23) LAZY(24) LAZY(25)
 120 void *OPENSSL_UplinkTable[] = {
 121     (void *)APPLINK_MAX,
 122     lazy1, lazy2, lazy3, lazy4, lazy5,
 123     lazy6, lazy7, lazy8, lazy9, lazy10,
 124     lazy11, lazy12, lazy13, lazy14, lazy15,
 125     lazy16, lazy17, lazy18, lazy19, lazy20,
 126     lazy21, lazy22, lazy23, lazy24, lazy25,
 127 };
 128 #endif
 129
 130 #ifdef SELFTEST
 131 main()
 132 {
 133     UP_fprintf(UP_stdout, "hello, world!\n");
 134 }
 135 #endif