xref: /openssl/ms/uplink.c (revision f5afac4b)
1 /*
2  * Copyright 2004-2021 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 
unimplemented(void)28 static void unimplemented(void)
29 {
30     OPENSSL_showfatal(sizeof(TCHAR) == sizeof(char) ? "%s\n" : "%S\n", msg);
31     TerminateProcess(GetCurrentProcess(), 1);
32 }
33 
OPENSSL_Uplink(volatile void ** table,int index)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(__BORLANDC__)) && defined(_M_IX86)
103 # if defined(_MSC_VER)
104 #  define LAZY(i)         \
105 __declspec(naked) static void lazy##i (void) {  \
106         _asm    push i                          \
107         _asm    push OFFSET OPENSSL_UplinkTable \
108         _asm    call OPENSSL_Uplink             \
109         _asm    add  esp,8                      \
110         _asm    jmp  OPENSSL_UplinkTable+4*i    }
111 # elif defined(__BORLANDC__) && defined(__clang__)
112 void *OPENSSL_UplinkTable[26]; /* C++Builder requires declaration before use */
113 #  define LAZY(i)         \
114 __declspec(naked) static void lazy##i (void) { \
115     __asm__("pushl $" #i "; "                  \
116             "pushl %0; "                       \
117             "call  %P1; "                      \
118             "addl  $8, %%esp; "                \
119             "jmp   *%2 "                       \
120             : /* no outputs */                 \
121             : "i" (OPENSSL_UplinkTable),       \
122               "i" (OPENSSL_Uplink),            \
123               "m" (OPENSSL_UplinkTable[i]));   }
124 # endif
125 
126 # if APPLINK_MAX>25
127 #  error "Add more stubs..."
128 # endif
129 /* make some in advance... */
130 LAZY(1) LAZY(2) LAZY(3) LAZY(4) LAZY(5)
131     LAZY(6) LAZY(7) LAZY(8) LAZY(9) LAZY(10)
132     LAZY(11) LAZY(12) LAZY(13) LAZY(14) LAZY(15)
133     LAZY(16) LAZY(17) LAZY(18) LAZY(19) LAZY(20)
134     LAZY(21) LAZY(22) LAZY(23) LAZY(24) LAZY(25)
135 void *OPENSSL_UplinkTable[] = {
136     (void *)APPLINK_MAX,
137     lazy1, lazy2, lazy3, lazy4, lazy5,
138     lazy6, lazy7, lazy8, lazy9, lazy10,
139     lazy11, lazy12, lazy13, lazy14, lazy15,
140     lazy16, lazy17, lazy18, lazy19, lazy20,
141     lazy21, lazy22, lazy23, lazy24, lazy25,
142 };
143 #endif
144 
145 #ifdef SELFTEST
main()146 main()
147 {
148     UP_fprintf(UP_stdout, "hello, world!\n");
149 }
150 #endif
151