| 1 | /* |
| 2 | * dlfcn-win32 |
| 3 | * Copyright (c) 2007 Ramiro Polla |
| 4 | * |
| 5 | * This library is free software; you can redistribute it and/or |
| 6 | * modify it under the terms of the GNU Lesser General Public |
| 7 | * License as published by the Free Software Foundation; either |
| 8 | * version 2.1 of the License, or (at your option) any later version. |
| 9 | * |
| 10 | * This library is distributed in the hope that it will be useful, |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 13 | * Lesser General Public License for more details. |
| 14 | * |
| 15 | * You should have received a copy of the GNU Lesser General Public |
| 16 | * License along with this library; if not, write to the Free Software |
| 17 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 18 | */ |
| 19 | |
| 20 | #include <windows.h> |
| 21 | #include <stdio.h> |
| 22 | |
| 23 | #include "dlfcn-win32.h" |
| 24 | |
| 25 | /* Note: |
| 26 | * MSDN says these functions are not thread-safe. We make no efforts to have |
| 27 | * any kind of thread safety. |
| 28 | */ |
| 29 | |
| 30 | /* I have no special reason to have set MAX_GLOBAL_OBJECTS to this value. Any |
| 31 | * comments are welcome. |
| 32 | */ |
| 33 | #define MAX_OBJECTS 255 |
| 34 | |
| 35 | static HMODULE global_objects[MAX_OBJECTS]; |
| 36 | |
| 37 | /* This function adds an object to the list of global objects. |
| 38 | * The implementation is very simple and slow. |
| 39 | * TODO: should failing this function be enough to fail the call to dlopen( )? |
| 40 | */ |
| 41 | static void global_object_add( HMODULE hModule ) |
| 42 | { |
| 43 | int i; |
| 44 | |
| 45 | for( i = 0 ; i < MAX_OBJECTS ; i++ ) |
| 46 | { |
| 47 | if( !global_objects[i] ) |
| 48 | { |
| 49 | global_objects[i] = hModule; |
| 50 | break; |
| 51 | } |
| 52 | } |
| 53 | } |
| 54 | |
| 55 | static void global_object_rem( HMODULE hModule ) |
| 56 | { |
| 57 | int i; |
| 58 | |
| 59 | for( i = 0 ; i < MAX_OBJECTS ; i++ ) |
| 60 | { |
| 61 | if( global_objects[i] == hModule ) |
| 62 | { |
| 63 | global_objects[i] = 0; |
| 64 | break; |
| 65 | } |
| 66 | } |
| 67 | } |
| 68 | |
| 69 | /* Argument to last function. Used in dlerror( ) */ |
| 70 | static char last_name[MAX_PATH]; |
| 71 | |
| 72 | static int copy_string( char *dest, int dest_size, const char *src ) |
| 73 | { |
| 74 | int i = 0; |
| 75 | |
| 76 | if( src && dest ) |
| 77 | { |
| 78 | for( i = 0 ; i < dest_size-1 ; i++ ) |
| 79 | { |
| 80 | if( !src[i] ) |
| 81 | break; |
| 82 | else |
| 83 | dest[i] = src[i]; |
| 84 | } |
| 85 | } |
| 86 | dest[i] = '\0'; |
| 87 | |
| 88 | return i; |
| 89 | } |
| 90 | |
| 91 | void *dlopen( const char *file, int mode ) |
| 92 | { |
| 93 | HMODULE hModule; |
| 94 | UINT uMode; |
| 95 | |
| 96 | /* Do not let Windows display the critical-error-handler message box */ |
| 97 | uMode = SetErrorMode( SEM_FAILCRITICALERRORS ); |
| 98 | |
| 99 | if( file == 0 ) |
| 100 | { |
| 101 | /* Save NULL pointer for error message */ |
| 102 | _snprintf_s( last_name, MAX_PATH, MAX_PATH, "0x%p", file ); |
| 103 | |
| 104 | /* POSIX says that if the value of file is 0, a handle on a global |
| 105 | * symbol object must be provided. That object must be able to access |
| 106 | * all symbols from the original program file, and any objects loaded |
| 107 | * with the RTLD_GLOBAL flag. |
| 108 | * The return value from GetModuleHandle( ) allows us to retrieve |
| 109 | * symbols only from the original program file. For objects loaded with |
| 110 | * the RTLD_GLOBAL flag, we create our own list later on. |
| 111 | */ |
| 112 | hModule = GetModuleHandle( NULL ); |
| 113 | } |
| 114 | else |
| 115 | { |
| 116 | char lpFileName[MAX_PATH]; |
| 117 | int i; |
| 118 | |
| 119 | /* MSDN says backslashes *must* be used instead of forward slashes. */ |
| 120 | for( i = 0 ; i < sizeof(lpFileName)-1 ; i++ ) |
| 121 | { |
| 122 | if( !file[i] ) |
| 123 | break; |
| 124 | else if( file[i] == '/' ) |
| 125 | lpFileName[i] = '\\'; |
| 126 | else |
| 127 | lpFileName[i] = file[i]; |
| 128 | } |
| 129 | lpFileName[i] = '\0'; |
| 130 | |
| 131 | /* Save file name for error message */ |
| 132 | copy_string( last_name, sizeof(last_name), lpFileName ); |
| 133 | |
| 134 | /* POSIX says the search path is implementation-defined. |
| 135 | * LOAD_WITH_ALTERED_SEARCH_PATH is used to make it behave more closely |
| 136 | * to UNIX's search paths (start with system folders instead of current |
| 137 | * folder). |
| 138 | */ |
| 139 | hModule = LoadLibraryEx( (LPSTR) lpFileName, NULL, |
| 140 | LOAD_WITH_ALTERED_SEARCH_PATH ); |
| 141 | /* If the object was loaded with RTLD_GLOBAL, add it to list of global |
| 142 | * objects, so that its symbols may be retrieved even if the handle for |
| 143 | * the original program file is passed. POSIX says that if the same |
| 144 | * file is specified in multiple invocations, and any of them are |
| 145 | * RTLD_GLOBAL, even if any further invocations use RTLD_LOCAL, the |
| 146 | * symbols will remain global. |
| 147 | */ |
| 148 | |
| 149 | if( hModule && (mode & RTLD_GLOBAL) ) |
| 150 | global_object_add( hModule ); |
| 151 | } |
| 152 | |
| 153 | /* Return to previous state of the error-mode bit flags. */ |
| 154 | SetErrorMode( uMode ); |
| 155 | |
| 156 | return (void *) hModule; |
| 157 | } |
| 158 | |
| 159 | int dlclose( void *handle ) |
| 160 | { |
| 161 | HMODULE hModule = (HMODULE) handle; |
| 162 | BOOL ret; |
| 163 | |
| 164 | /* Save handle for error message */ |
| 165 | _snprintf_s( last_name, MAX_PATH, MAX_PATH, "0x%p", handle ); |
| 166 | |
| 167 | ret = FreeLibrary( hModule ); |
| 168 | |
| 169 | /* If the object was loaded with RTLD_GLOBAL, remove it from list of global |
| 170 | * objects. |
| 171 | */ |
| 172 | if( ret ) |
| 173 | global_object_rem( hModule ); |
| 174 | |
| 175 | /* dlclose's return value in inverted in relation to FreeLibrary's. */ |
| 176 | ret = !ret; |
| 177 | |
| 178 | return (int) ret; |
| 179 | } |
| 180 | |
| 181 | void *dlsym( void *handle, const char *name ) |
| 182 | { |
| 183 | FARPROC symbol; |
| 184 | HMODULE myhandle = (HMODULE) handle; |
| 185 | |
| 186 | /* Save symbol name for error message */ |
| 187 | copy_string( last_name, sizeof(last_name), name ); |
| 188 | |
| 189 | symbol = GetProcAddress( myhandle, name ); |
| 190 | #if 0 |
| 191 | if( symbol == NULL ) |
| 192 | { |
| 193 | HMODULE hModule; |
| 194 | |
| 195 | /* If the handle for the original program file is passed, also search |
| 196 | * in all globally loaded objects. |
| 197 | */ |
| 198 | |
| 199 | hModule = GetModuleHandle( NULL ); |
| 200 | |
| 201 | if( hModule == handle ) |
| 202 | { |
| 203 | int i; |
| 204 | |
| 205 | for( i = 0 ; i < MAX_OBJECTS ; i++ ) |
| 206 | { |
| 207 | if( global_objects[i] != 0 ) |
| 208 | { |
| 209 | symbol = GetProcAddress( global_objects[i], name ); |
| 210 | if( symbol != NULL ) |
| 211 | break; |
| 212 | } |
| 213 | } |
| 214 | } |
| 215 | |
| 216 | |
| 217 | CloseHandle( hModule ); |
| 218 | } |
| 219 | #endif |
| 220 | return (void*) symbol; |
| 221 | } |
| 222 | |
| 223 | char *dlerror( void ) |
| 224 | { |
| 225 | DWORD dwMessageId; |
| 226 | /* POSIX says this function doesn't have to be thread-safe, so we use one |
| 227 | * static buffer. |
| 228 | * MSDN says the buffer cannot be larger than 64K bytes, so we set it to |
| 229 | * the limit. |
| 230 | */ |
| 231 | static char lpBuffer[65535]; |
| 232 | DWORD ret; |
| 233 | |
| 234 | dwMessageId = GetLastError( ); |
| 235 | |
| 236 | if( dwMessageId == 0 ) |
| 237 | return NULL; |
| 238 | |
| 239 | /* Format error message to: |
| 240 | * "<argument to function that failed>": <Windows localized error message> |
| 241 | */ |
| 242 | ret = copy_string( lpBuffer, sizeof(lpBuffer), "\"" ); |
| 243 | ret += copy_string( lpBuffer+ret, sizeof(lpBuffer)-ret, last_name ); |
| 244 | ret += copy_string( lpBuffer+ret, sizeof(lpBuffer)-ret, "\": " ); |
| 245 | ret += FormatMessage( FORMAT_MESSAGE_FROM_SYSTEM, NULL, dwMessageId, |
| 246 | MAKELANGID( LANG_NEUTRAL, SUBLANG_DEFAULT ), |
| 247 | lpBuffer+ret, sizeof(lpBuffer)-ret, NULL ); |
| 248 | |
| 249 | if( ret > 1 ) |
| 250 | { |
| 251 | /* POSIX says the string must not have trailing <newline> */ |
| 252 | if( lpBuffer[ret-2] == '\r' && lpBuffer[ret-1] == '\n' ) |
| 253 | lpBuffer[ret-2] = '\0'; |
| 254 | } |
| 255 | |
| 256 | /* POSIX says that invoking dlerror( ) a second time, immediately following |
| 257 | * a prior invocation, shall result in NULL being returned. |
| 258 | */ |
| 259 | SetLastError(0); |
| 260 | |
| 261 | return lpBuffer; |
| 262 | } |
| 263 | |