dlfcn_test.cpp revision 498eb18b82a425f9f30132e4832f327b2ee0e545
1/* 2 * Copyright (C) 2012 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17#include <gtest/gtest.h> 18 19#include <dlfcn.h> 20#include <libgen.h> 21#include <limits.h> 22#include <stdio.h> 23#include <stdint.h> 24 25#include "private/ScopeGuard.h" 26 27#include <string> 28 29#define ASSERT_SUBSTR(needle, haystack) \ 30 ASSERT_PRED_FORMAT2(::testing::IsSubstring, needle, haystack) 31 32static bool g_called = false; 33extern "C" void DlSymTestFunction() { 34 g_called = true; 35} 36 37static int g_ctor_function_called = 0; 38 39extern "C" void ctor_function() __attribute__ ((constructor)); 40 41extern "C" void ctor_function() { 42 g_ctor_function_called = 17; 43} 44 45TEST(dlfcn, ctor_function_call) { 46 ASSERT_EQ(17, g_ctor_function_called); 47} 48 49TEST(dlfcn, dlsym_in_self) { 50 dlerror(); // Clear any pending errors. 51 void* self = dlopen(NULL, RTLD_NOW); 52 ASSERT_TRUE(self != NULL); 53 ASSERT_TRUE(dlerror() == NULL); 54 55 void* sym = dlsym(self, "DlSymTestFunction"); 56 ASSERT_TRUE(sym != NULL); 57 58 void (*function)() = reinterpret_cast<void(*)()>(sym); 59 60 g_called = false; 61 function(); 62 ASSERT_TRUE(g_called); 63 64 ASSERT_EQ(0, dlclose(self)); 65} 66 67TEST(dlfcn, dlsym_with_dependencies) { 68 void* handle = dlopen("libtest_with_dependency.so", RTLD_NOW); 69 ASSERT_TRUE(handle != NULL); 70 dlerror(); 71 // This symbol is in DT_NEEDED library. 72 void* sym = dlsym(handle, "getRandomNumber"); 73 ASSERT_TRUE(sym != NULL); 74 int (*fn)(void); 75 fn = reinterpret_cast<int (*)(void)>(sym); 76 EXPECT_EQ(4, fn()); 77 dlclose(handle); 78} 79 80TEST(dlfcn, dlopen_noload) { 81 void* handle = dlopen("libtest_simple.so", RTLD_NOW | RTLD_NOLOAD); 82 ASSERT_TRUE(handle == NULL); 83 handle = dlopen("libtest_simple.so", RTLD_NOW); 84 void* handle2 = dlopen("libtest_simple.so", RTLD_NOW | RTLD_NOLOAD); 85 ASSERT_TRUE(handle != NULL); 86 ASSERT_TRUE(handle2 != NULL); 87 ASSERT_TRUE(handle == handle2); 88 ASSERT_EQ(0, dlclose(handle)); 89 ASSERT_EQ(0, dlclose(handle2)); 90} 91 92// ifuncs are only supported on intel for now 93#if defined(__i386__) || defined(__x86_64__) 94TEST(dlfcn, ifunc) { 95 typedef const char* (*fn_ptr)(); 96 97 // ifunc's choice depends on whether IFUNC_CHOICE has a value 98 // first check the set case 99 setenv("IFUNC_CHOICE", "set", 1); 100 void* handle = dlopen("libtest_ifunc.so", RTLD_NOW); 101 ASSERT_TRUE(handle != NULL); 102 fn_ptr foo_ptr = reinterpret_cast<fn_ptr>(dlsym(handle, "foo")); 103 fn_ptr foo_library_ptr = reinterpret_cast<fn_ptr>(dlsym(handle, "foo_library")); 104 ASSERT_TRUE(foo_ptr != NULL); 105 ASSERT_TRUE(foo_library_ptr != NULL); 106 ASSERT_EQ(strncmp("set", foo_ptr(), 3), 0); 107 ASSERT_EQ(strncmp("set", foo_library_ptr(), 3), 0); 108 dlclose(handle); 109 110 // then check the unset case 111 unsetenv("IFUNC_CHOICE"); 112 handle = dlopen("libtest_ifunc.so", RTLD_NOW); 113 ASSERT_TRUE(handle != NULL); 114 foo_ptr = reinterpret_cast<fn_ptr>(dlsym(handle, "foo")); 115 foo_library_ptr = reinterpret_cast<fn_ptr>(dlsym(handle, "foo_library")); 116 ASSERT_TRUE(foo_ptr != NULL); 117 ASSERT_TRUE(foo_library_ptr != NULL); 118 ASSERT_EQ(strncmp("unset", foo_ptr(), 5), 0); 119 ASSERT_EQ(strncmp("unset", foo_library_ptr(), 3), 0); 120 dlclose(handle); 121} 122 123TEST(dlfcn, ifunc_ctor_call) { 124 typedef const char* (*fn_ptr)(); 125 126 void* handle = dlopen("libtest_ifunc.so", RTLD_NOW); 127 ASSERT_TRUE(handle != NULL) << dlerror(); 128 fn_ptr is_ctor_called = reinterpret_cast<fn_ptr>(dlsym(handle, "is_ctor_called")); 129 ASSERT_TRUE(is_ctor_called != NULL) << dlerror(); 130 ASSERT_STREQ("true", is_ctor_called()); 131 dlclose(handle); 132} 133#endif 134 135TEST(dlfcn, dlopen_check_relocation_dt_needed_order) { 136 // This is the structure of the test library and 137 // its dt_needed libraries 138 // libtest_relo_check_dt_needed_order.so 139 // | 140 // +-> libtest_relo_check_dt_needed_order_1.so 141 // | 142 // +-> libtest_relo_check_dt_needed_order_2.so 143 // 144 // The root library references relo_test_get_answer_lib - which is defined 145 // in both dt_needed libraries, the correct relocation should 146 // use the function defined in libtest_relo_check_dt_needed_order_1.so 147 void* handle = nullptr; 148 auto guard = create_scope_guard([&]() { 149 dlclose(handle); 150 }); 151 152 handle = dlopen("libtest_relo_check_dt_needed_order.so", RTLD_NOW); 153 ASSERT_TRUE(handle != nullptr) << dlerror(); 154 155 typedef int (*fn_t) (void); 156 fn_t fn = reinterpret_cast<fn_t>(dlsym(handle, "relo_test_get_answer")); 157 ASSERT_TRUE(fn != nullptr) << dlerror(); 158 ASSERT_EQ(1, fn()); 159} 160 161TEST(dlfcn, dlopen_failure) { 162 void* self = dlopen("/does/not/exist", RTLD_NOW); 163 ASSERT_TRUE(self == NULL); 164#if defined(__BIONIC__) 165 ASSERT_STREQ("dlopen failed: library \"/does/not/exist\" not found", dlerror()); 166#else 167 ASSERT_STREQ("/does/not/exist: cannot open shared object file: No such file or directory", dlerror()); 168#endif 169} 170 171static void* ConcurrentDlErrorFn(void*) { 172 dlopen("/child/thread", RTLD_NOW); 173 return reinterpret_cast<void*>(strdup(dlerror())); 174} 175 176TEST(dlfcn, dlerror_concurrent) { 177 dlopen("/main/thread", RTLD_NOW); 178 const char* main_thread_error = dlerror(); 179 ASSERT_SUBSTR("/main/thread", main_thread_error); 180 181 pthread_t t; 182 ASSERT_EQ(0, pthread_create(&t, NULL, ConcurrentDlErrorFn, NULL)); 183 void* result; 184 ASSERT_EQ(0, pthread_join(t, &result)); 185 char* child_thread_error = static_cast<char*>(result); 186 ASSERT_SUBSTR("/child/thread", child_thread_error); 187 free(child_thread_error); 188 189 ASSERT_SUBSTR("/main/thread", main_thread_error); 190} 191 192TEST(dlfcn, dlsym_failures) { 193 dlerror(); // Clear any pending errors. 194 void* self = dlopen(NULL, RTLD_NOW); 195 ASSERT_TRUE(self != NULL); 196 ASSERT_TRUE(dlerror() == NULL); 197 198 void* sym; 199 200#if defined(__BIONIC__) && !defined(__LP64__) 201 // RTLD_DEFAULT in lp32 bionic is not (void*)0 202 // so it can be distinguished from the NULL handle. 203 sym = dlsym(NULL, "test"); 204 ASSERT_TRUE(sym == NULL); 205 ASSERT_SUBSTR("dlsym library handle is null", dlerror()); 206#endif 207 208 // NULL symbol name. 209#if defined(__BIONIC__) 210 // glibc marks this parameter non-null and SEGVs if you cheat. 211 sym = dlsym(self, NULL); 212 ASSERT_TRUE(sym == NULL); 213 ASSERT_SUBSTR("", dlerror()); 214#endif 215 216 // Symbol that doesn't exist. 217 sym = dlsym(self, "ThisSymbolDoesNotExist"); 218 ASSERT_TRUE(sym == NULL); 219 ASSERT_SUBSTR("undefined symbol: ThisSymbolDoesNotExist", dlerror()); 220 221 ASSERT_EQ(0, dlclose(self)); 222} 223 224TEST(dlfcn, dladdr) { 225 dlerror(); // Clear any pending errors. 226 void* self = dlopen(NULL, RTLD_NOW); 227 ASSERT_TRUE(self != NULL); 228 ASSERT_TRUE(dlerror() == NULL); 229 230 void* sym = dlsym(self, "DlSymTestFunction"); 231 ASSERT_TRUE(sym != NULL); 232 233 // Deliberately ask dladdr for an address inside a symbol, rather than the symbol base address. 234 void* addr = reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(sym) + 2); 235 236 Dl_info info; 237 int rc = dladdr(addr, &info); 238 ASSERT_NE(rc, 0); // Zero on error, non-zero on success. 239 240 // Get the name of this executable. 241 char executable_path[PATH_MAX]; 242 rc = readlink("/proc/self/exe", executable_path, sizeof(executable_path)); 243 ASSERT_NE(rc, -1); 244 executable_path[rc] = '\0'; 245 std::string executable_name(basename(executable_path)); 246 247 // The filename should be that of this executable. 248 // Note that we don't know whether or not we have the full path, so we want an "ends_with" test. 249 std::string dli_fname(info.dli_fname); 250 dli_fname = basename(&dli_fname[0]); 251 ASSERT_EQ(dli_fname, executable_name); 252 253 // The symbol name should be the symbol we looked up. 254 ASSERT_STREQ(info.dli_sname, "DlSymTestFunction"); 255 256 // The address should be the exact address of the symbol. 257 ASSERT_EQ(info.dli_saddr, sym); 258 259 // Look in /proc/pid/maps to find out what address we were loaded at. 260 // TODO: factor /proc/pid/maps parsing out into a class and reuse all over bionic. 261 void* base_address = NULL; 262 char line[BUFSIZ]; 263 FILE* fp = fopen("/proc/self/maps", "r"); 264 ASSERT_TRUE(fp != NULL); 265 while (fgets(line, sizeof(line), fp) != NULL) { 266 uintptr_t start = strtoul(line, 0, 16); 267 line[strlen(line) - 1] = '\0'; // Chomp the '\n'. 268 char* path = strchr(line, '/'); 269 if (path != NULL && strcmp(executable_path, path) == 0) { 270 base_address = reinterpret_cast<void*>(start); 271 break; 272 } 273 } 274 fclose(fp); 275 276 // The base address should be the address we were loaded at. 277 ASSERT_EQ(info.dli_fbase, base_address); 278 279 ASSERT_EQ(0, dlclose(self)); 280} 281 282TEST(dlfcn, dladdr_invalid) { 283 Dl_info info; 284 285 dlerror(); // Clear any pending errors. 286 287 // No symbol corresponding to NULL. 288 ASSERT_EQ(dladdr(NULL, &info), 0); // Zero on error, non-zero on success. 289 ASSERT_TRUE(dlerror() == NULL); // dladdr(3) doesn't set dlerror(3). 290 291 // No symbol corresponding to a stack address. 292 ASSERT_EQ(dladdr(&info, &info), 0); // Zero on error, non-zero on success. 293 ASSERT_TRUE(dlerror() == NULL); // dladdr(3) doesn't set dlerror(3). 294} 295 296// Our dynamic linker doesn't support GNU hash tables. 297#if defined(__BIONIC__) 298// GNU-style ELF hash tables are incompatible with the MIPS ABI. 299// MIPS requires .dynsym to be sorted to match the GOT but GNU-style requires sorting by hash code. 300#if !defined(__mips__) 301TEST(dlfcn, dlopen_library_with_only_gnu_hash) { 302 dlerror(); // Clear any pending errors. 303 void* handle = dlopen("no-elf-hash-table-library.so", RTLD_NOW); 304 ASSERT_TRUE(handle == NULL); 305 ASSERT_STREQ("dlopen failed: empty/missing DT_HASH in \"no-elf-hash-table-library.so\" (built with --hash-style=gnu?)", dlerror()); 306} 307#endif 308#endif 309 310TEST(dlfcn, dlopen_bad_flags) { 311 dlerror(); // Clear any pending errors. 312 void* handle; 313 314#if defined(__GLIBC__) 315 // glibc was smart enough not to define RTLD_NOW as 0, so it can detect missing flags. 316 handle = dlopen(NULL, 0); 317 ASSERT_TRUE(handle == NULL); 318 ASSERT_SUBSTR("invalid", dlerror()); 319#endif 320 321 handle = dlopen(NULL, 0xffffffff); 322 ASSERT_TRUE(handle == NULL); 323 ASSERT_SUBSTR("invalid", dlerror()); 324 325 // glibc actually allows you to choose both RTLD_NOW and RTLD_LAZY at the same time, and so do we. 326 handle = dlopen(NULL, RTLD_NOW|RTLD_LAZY); 327 ASSERT_TRUE(handle != NULL); 328 ASSERT_SUBSTR(NULL, dlerror()); 329} 330 331TEST(dlfcn, rtld_default_unknown_symbol) { 332 void* addr = dlsym(RTLD_DEFAULT, "ANY_UNKNOWN_SYMBOL_NAME"); 333 ASSERT_TRUE(addr == NULL); 334} 335 336TEST(dlfcn, rtld_default_known_symbol) { 337 void* addr = dlsym(RTLD_DEFAULT, "fopen"); 338 ASSERT_TRUE(addr != NULL); 339} 340 341TEST(dlfcn, rtld_next_unknown_symbol) { 342 void* addr = dlsym(RTLD_NEXT, "ANY_UNKNOWN_SYMBOL_NAME"); 343 ASSERT_TRUE(addr == NULL); 344} 345 346TEST(dlfcn, rtld_next_known_symbol) { 347 void* addr = dlsym(RTLD_NEXT, "fopen"); 348 ASSERT_TRUE(addr != NULL); 349} 350 351TEST(dlfcn, dlsym_weak_func) { 352 dlerror(); 353 void* handle = dlopen("libtest_dlsym_weak_func.so",RTLD_NOW); 354 ASSERT_TRUE(handle != NULL); 355 356 int (*weak_func)(); 357 weak_func = reinterpret_cast<int (*)()>(dlsym(handle, "weak_func")); 358 ASSERT_TRUE(weak_func != NULL) << "dlerror: " << dlerror(); 359 EXPECT_EQ(42, weak_func()); 360 dlclose(handle); 361} 362 363TEST(dlfcn, dlopen_symlink) { 364 void* handle1 = dlopen("libdlext_test.so", RTLD_NOW); 365 void* handle2 = dlopen("libdlext_test_v2.so", RTLD_NOW); 366 ASSERT_TRUE(handle1 != NULL); 367 ASSERT_TRUE(handle2 != NULL); 368 ASSERT_EQ(handle1, handle2); 369 dlclose(handle1); 370 dlclose(handle2); 371} 372