uplink.c
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/*
* Copyright 2004-2016 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the OpenSSL license (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#if (defined(_WIN64) || defined(_WIN32_WCE)) && !defined(UNICODE)
# define UNICODE
#endif
#if defined(UNICODE) && !defined(_UNICODE)
# define _UNICODE
#endif
#if defined(_UNICODE) && !defined(UNICODE)
# define UNICODE
#endif
#include <windows.h>
#include <tchar.h>
#include <stdio.h>
#include "uplink.h"
void OPENSSL_showfatal(const char *, ...);
static TCHAR msg[128];
static void unimplemented(void)
{
OPENSSL_showfatal(sizeof(TCHAR) == sizeof(char) ? "%s\n" : "%S\n", msg);
ExitProcess(1);
}
void OPENSSL_Uplink(volatile void **table, int index)
{
static HMODULE volatile apphandle = NULL;
static void **volatile applinktable = NULL;
int len;
void (*func) (void) = unimplemented;
HANDLE h;
void **p;
/*
* Note that the below code is not MT-safe in respect to msg buffer, but
* what's the worst thing that can happen? Error message might be
* misleading or corrupted. As error condition is fatal and should never
* be risen, I accept the risk...
*/
/*
* One can argue that I should have used InterlockedExchangePointer or
* something to update static variables and table[]. Well, store
* instructions are as atomic as they can get and assigned values are
* effectively constant... So that volatile qualifier should be
* sufficient [it prohibits compiler to reorder memory access
* instructions].
*/
do {
len = _sntprintf(msg, sizeof(msg) / sizeof(TCHAR),
_T("OPENSSL_Uplink(%p,%02X): "), table, index);
_tcscpy(msg + len, _T("unimplemented function"));
if ((h = apphandle) == NULL) {
if ((h = GetModuleHandle(NULL)) == NULL) {
apphandle = (HMODULE) - 1;
_tcscpy(msg + len, _T("no host application"));
break;
}
apphandle = h;
}
if ((h = apphandle) == (HMODULE) - 1) /* revalidate */
break;
if (applinktable == NULL) {
void **(*applink) ();
applink = (void **(*)())GetProcAddress(h, "OPENSSL_Applink");
if (applink == NULL) {
apphandle = (HMODULE) - 1;
_tcscpy(msg + len, _T("no OPENSSL_Applink"));
break;
}
p = (*applink) ();
if (p == NULL) {
apphandle = (HMODULE) - 1;
_tcscpy(msg + len, _T("no ApplinkTable"));
break;
}
applinktable = p;
} else
p = applinktable;
if (index > (int)p[0])
break;
if (p[index])
func = p[index];
} while (0);
table[index] = func;
}
#if defined(_MSC_VER) && defined(_M_IX86)
# define LAZY(i) \
__declspec(naked) static void lazy##i (void) { \
_asm push i \
_asm push OFFSET OPENSSL_UplinkTable \
_asm call OPENSSL_Uplink \
_asm add esp,8 \
_asm jmp OPENSSL_UplinkTable+4*i }
# if APPLINK_MAX>25
# error "Add more stubs..."
# endif
/* make some in advance... */
LAZY(1) LAZY(2) LAZY(3) LAZY(4) LAZY(5)
LAZY(6) LAZY(7) LAZY(8) LAZY(9) LAZY(10)
LAZY(11) LAZY(12) LAZY(13) LAZY(14) LAZY(15)
LAZY(16) LAZY(17) LAZY(18) LAZY(19) LAZY(20)
LAZY(21) LAZY(22) LAZY(23) LAZY(24) LAZY(25)
void *OPENSSL_UplinkTable[] = {
(void *)APPLINK_MAX,
lazy1, lazy2, lazy3, lazy4, lazy5,
lazy6, lazy7, lazy8, lazy9, lazy10,
lazy11, lazy12, lazy13, lazy14, lazy15,
lazy16, lazy17, lazy18, lazy19, lazy20,
lazy21, lazy22, lazy23, lazy24, lazy25,
};
#endif
#ifdef SELFTEST
main()
{
UP_fprintf(UP_stdout, "hello, world!\n");
}
#endif