1 /* 2 * Copyright 2013 Intel Corporation 3 * 4 * Permission is hereby granted, free of charge, to any person obtaining a 5 * copy of this software and associated documentation files (the "Software"), 6 * to deal in the Software without restriction, including without limitation 7 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 8 * and/or sell copies of the Software, and to permit persons to whom the 9 * Software is furnished to do so, subject to the following conditions: 10 * 11 * The above copyright notice and this permission notice (including the next 12 * paragraph) shall be included in all copies or substantial portions of the 13 * Software. 14 * 15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 21 * IN THE SOFTWARE. 22 */ 23 24 #include <stdio.h> 25 #include "dri_util.h" 26 #include <dlfcn.h> 27 #include "main/macros.h" 28 29 /* We need GNU extensions to dlfcn.h in order to provide backward 30 * compatibility for the older DRI driver loader mechanism. (dladdr, 31 * Dl_info, and RTLD_DEFAULT) 32 */ 33 #if defined(RTLD_DEFAULT) && defined(HAVE_DLADDR) 34 35 #define MEGADRIVER_STUB_MAX_EXTENSIONS 10 36 #define LIB_PATH_SUFFIX "_dri.so" 37 #define LIB_PATH_SUFFIX_LENGTH (sizeof(LIB_PATH_SUFFIX)-1) 38 39 /* This is the table of extensions that the loader will dlsym() for. 40 * 41 * Initially it is empty for the megadriver stub, but the library 42 * constructor may initialize it based on the name of the library that 43 * is being loaded. 44 */ 45 PUBLIC const __DRIextension * 46 __driDriverExtensions[MEGADRIVER_STUB_MAX_EXTENSIONS] = { 47 NULL 48 }; 49 50 /** 51 * This is a constructor function for the megadriver dynamic library. 52 * 53 * When the driver is dlopen'ed, this function will run. It will 54 * search for the name of the foo_dri.so file that was opened using 55 * the dladdr function. 56 * 57 * After finding foo's name, it will call __driDriverGetExtensions_foo 58 * and use the return to update __driDriverExtensions to enable 59 * compatibility with older DRI driver loaders. 60 */ 61 __attribute__((constructor)) static void 62 megadriver_stub_init(void) 63 { 64 Dl_info info; 65 char *driver_name; 66 size_t name_len; 67 char *get_extensions_name; 68 const __DRIextension **(*get_extensions)(void); 69 const __DRIextension **extensions; 70 int i; 71 72 /* Call dladdr on __driDriverExtensions. We are really 73 * interested in the returned info.dli_fname so we can 74 * figure out the path name of the library being loaded. 75 */ 76 i = dladdr((void*) __driDriverExtensions, &info); 77 if (i == 0) 78 return; 79 80 /* Search for the last '/' character in the path. */ 81 driver_name = strrchr(info.dli_fname, '/'); 82 if (driver_name != NULL) { 83 /* Skip '/' character */ 84 driver_name++; 85 } else { 86 /* Try using the start of the path */ 87 driver_name = (char*) info.dli_fname; 88 } 89 90 /* Make sure the path ends with _dri.so */ 91 name_len = strlen(driver_name); 92 i = name_len - LIB_PATH_SUFFIX_LENGTH; 93 if (i < 0 || strcmp(driver_name + i, LIB_PATH_SUFFIX) != 0) 94 return; 95 96 /* Duplicate the string so we can modify it. 97 * So far we've been using info.dli_fname. 98 */ 99 driver_name = strdup(driver_name); 100 if (!driver_name) 101 return; 102 103 /* The path ends with _dri.so. Chop this part of the 104 * string off. Then we'll have the driver's final name. 105 */ 106 driver_name[i] = '\0'; 107 108 i = asprintf(&get_extensions_name, "%s_%s", 109 __DRI_DRIVER_GET_EXTENSIONS, driver_name); 110 free(driver_name); 111 if (i == -1) 112 return; 113 114 /* dlsym to get the driver's get extensions function. We 115 * don't have the dlopen handle, so we have to use 116 * RTLD_DEFAULT. It seems unlikely that the symbol will 117 * be found in another library, but this isn't optimal. 118 */ 119 get_extensions = dlsym(RTLD_DEFAULT, get_extensions_name); 120 free(get_extensions_name); 121 if (!get_extensions) 122 return; 123 124 /* Use the newer DRI loader entrypoint to find extensions. 125 * We will then expose these extensions via the older 126 * __driDriverExtensions symbol. 127 */ 128 extensions = get_extensions(); 129 130 /* Copy the extensions into the __driDriverExtensions array 131 * we declared. 132 */ 133 for (i = 0; i < ARRAY_SIZE(__driDriverExtensions); i++) { 134 __driDriverExtensions[i] = extensions[i]; 135 if (extensions[i] == NULL) 136 break; 137 } 138 139 /* If the driver had more extensions than we reserved, then 140 * bail out. 141 */ 142 if (i == ARRAY_SIZE(__driDriverExtensions)) { 143 __driDriverExtensions[0] = NULL; 144 fprintf(stderr, "Megadriver stub did not reserve enough extension " 145 "slots.\n"); 146 return; 147 } 148 } 149 150 #endif /* RTLD_DEFAULT && HAVE_DLADDR */ 151 152 static const 153 __DRIconfig **stub_error_init_screen(__DRIscreen *psp) 154 { 155 fprintf(stderr, "An updated DRI driver loader (libGL.so or X Server) is " 156 "required for this Mesa driver.\n"); 157 return NULL; 158 } 159 160 /** 161 * This is a stub driDriverAPI that is referenced by dri_util.c but should 162 * never be used. 163 */ 164 const struct __DriverAPIRec driDriverAPI = { 165 .InitScreen = stub_error_init_screen, 166 }; 167