dlfcn_test.cpp revision d06ee1d6db6165126161044fb662301bf9f04b3a
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 <string> 26 27#define ASSERT_SUBSTR(needle, haystack) \ 28 ASSERT_PRED_FORMAT2(::testing::IsSubstring, needle, haystack) 29 30static bool g_called = false; 31extern "C" void DlSymTestFunction() { 32 g_called = true; 33} 34 35TEST(dlfcn, dlsym_in_self) { 36 dlerror(); // Clear any pending errors. 37 void* self = dlopen(NULL, RTLD_NOW); 38 ASSERT_TRUE(self != NULL); 39 ASSERT_TRUE(dlerror() == NULL); 40 41 void* sym = dlsym(self, "DlSymTestFunction"); 42 ASSERT_TRUE(sym != NULL); 43 44 void (*function)() = reinterpret_cast<void(*)()>(sym); 45 46 g_called = false; 47 function(); 48 ASSERT_TRUE(g_called); 49 50 ASSERT_EQ(0, dlclose(self)); 51} 52 53TEST(dlfcn, dlsym_local_symbol) { 54 void* handle = dlopen("libtest_local_symbol.so", RTLD_NOW); 55 ASSERT_TRUE(handle != NULL); 56 dlerror(); 57 void* sym = dlsym(handle, "private_taxicab_number"); 58 ASSERT_TRUE(sym == NULL); 59 ASSERT_STREQ("undefined symbol: private_taxicab_number", dlerror()); 60 61 uint32_t (*f)(void); 62 f = reinterpret_cast<uint32_t (*)(void)>(dlsym(handle, "dlsym_local_symbol_get_taxicab_number_using_dlsym")); 63 ASSERT_TRUE(f != NULL); 64 ASSERT_EQ(1729U, f()); 65} 66 67TEST(dlfcn, dlopen_noload) { 68 void* handle = dlopen("libtest_simple.so", RTLD_NOW | RTLD_NOLOAD); 69 ASSERT_TRUE(handle == NULL); 70 handle = dlopen("libtest_simple.so", RTLD_NOW); 71 void* handle2 = dlopen("libtest_simple.so", RTLD_NOW | RTLD_NOLOAD); 72 ASSERT_TRUE(handle != NULL); 73 ASSERT_TRUE(handle2 != NULL); 74 ASSERT_TRUE(handle == handle2); 75 ASSERT_EQ(0, dlclose(handle)); 76 ASSERT_EQ(0, dlclose(handle2)); 77} 78 79TEST(dlfcn, dlopen_failure) { 80 void* self = dlopen("/does/not/exist", RTLD_NOW); 81 ASSERT_TRUE(self == NULL); 82#if defined(__BIONIC__) 83 ASSERT_STREQ("dlopen failed: library \"/does/not/exist\" not found", dlerror()); 84#else 85 ASSERT_STREQ("/does/not/exist: cannot open shared object file: No such file or directory", dlerror()); 86#endif 87} 88 89static void* ConcurrentDlErrorFn(void*) { 90 dlopen("/child/thread", RTLD_NOW); 91 return reinterpret_cast<void*>(strdup(dlerror())); 92} 93 94TEST(dlfcn, dlerror_concurrent) { 95 dlopen("/main/thread", RTLD_NOW); 96 const char* main_thread_error = dlerror(); 97 ASSERT_SUBSTR("/main/thread", main_thread_error); 98 99 pthread_t t; 100 ASSERT_EQ(0, pthread_create(&t, NULL, ConcurrentDlErrorFn, NULL)); 101 void* result; 102 ASSERT_EQ(0, pthread_join(t, &result)); 103 char* child_thread_error = static_cast<char*>(result); 104 ASSERT_SUBSTR("/child/thread", child_thread_error); 105 free(child_thread_error); 106 107 ASSERT_SUBSTR("/main/thread", main_thread_error); 108} 109 110TEST(dlfcn, dlsym_failures) { 111 dlerror(); // Clear any pending errors. 112 void* self = dlopen(NULL, RTLD_NOW); 113 ASSERT_TRUE(self != NULL); 114 ASSERT_TRUE(dlerror() == NULL); 115 116 void* sym; 117 118#if defined(__BIONIC__) && !defined(__LP64__) 119 // RTLD_DEFAULT in lp32 bionic is not (void*)0 120 // so it can be distinguished from the NULL handle. 121 sym = dlsym(NULL, "test"); 122 ASSERT_TRUE(sym == NULL); 123 ASSERT_SUBSTR("dlsym library handle is null", dlerror()); 124#endif 125 126 // NULL symbol name. 127#if defined(__BIONIC__) 128 // glibc marks this parameter non-null and SEGVs if you cheat. 129 sym = dlsym(self, NULL); 130 ASSERT_TRUE(sym == NULL); 131 ASSERT_SUBSTR("", dlerror()); 132#endif 133 134 // Symbol that doesn't exist. 135 sym = dlsym(self, "ThisSymbolDoesNotExist"); 136 ASSERT_TRUE(sym == NULL); 137 ASSERT_SUBSTR("undefined symbol: ThisSymbolDoesNotExist", dlerror()); 138 139 ASSERT_EQ(0, dlclose(self)); 140} 141 142TEST(dlfcn, dladdr) { 143 dlerror(); // Clear any pending errors. 144 void* self = dlopen(NULL, RTLD_NOW); 145 ASSERT_TRUE(self != NULL); 146 ASSERT_TRUE(dlerror() == NULL); 147 148 void* sym = dlsym(self, "DlSymTestFunction"); 149 ASSERT_TRUE(sym != NULL); 150 151 // Deliberately ask dladdr for an address inside a symbol, rather than the symbol base address. 152 void* addr = reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(sym) + 2); 153 154 Dl_info info; 155 int rc = dladdr(addr, &info); 156 ASSERT_NE(rc, 0); // Zero on error, non-zero on success. 157 158 // Get the name of this executable. 159 char executable_path[PATH_MAX]; 160 rc = readlink("/proc/self/exe", executable_path, sizeof(executable_path)); 161 ASSERT_NE(rc, -1); 162 executable_path[rc] = '\0'; 163 std::string executable_name(basename(executable_path)); 164 165 // The filename should be that of this executable. 166 // Note that we don't know whether or not we have the full path, so we want an "ends_with" test. 167 std::string dli_fname(info.dli_fname); 168 dli_fname = basename(&dli_fname[0]); 169 ASSERT_EQ(dli_fname, executable_name); 170 171 // The symbol name should be the symbol we looked up. 172 ASSERT_STREQ(info.dli_sname, "DlSymTestFunction"); 173 174 // The address should be the exact address of the symbol. 175 ASSERT_EQ(info.dli_saddr, sym); 176 177 // Look in /proc/pid/maps to find out what address we were loaded at. 178 // TODO: factor /proc/pid/maps parsing out into a class and reuse all over bionic. 179 void* base_address = NULL; 180 char path[PATH_MAX]; 181 snprintf(path, sizeof(path), "/proc/%d/maps", getpid()); 182 char line[BUFSIZ]; 183 FILE* fp = fopen(path, "r"); 184 ASSERT_TRUE(fp != NULL); 185 while (fgets(line, sizeof(line), fp) != NULL) { 186 uintptr_t start = strtoul(line, 0, 16); 187 line[strlen(line) - 1] = '\0'; // Chomp the '\n'. 188 char* path = strchr(line, '/'); 189 if (path != NULL && strcmp(executable_path, path) == 0) { 190 base_address = reinterpret_cast<void*>(start); 191 break; 192 } 193 } 194 fclose(fp); 195 196 // The base address should be the address we were loaded at. 197 ASSERT_EQ(info.dli_fbase, base_address); 198 199 ASSERT_EQ(0, dlclose(self)); 200} 201 202TEST(dlfcn, dladdr_invalid) { 203 Dl_info info; 204 205 dlerror(); // Clear any pending errors. 206 207 // No symbol corresponding to NULL. 208 ASSERT_EQ(dladdr(NULL, &info), 0); // Zero on error, non-zero on success. 209 ASSERT_TRUE(dlerror() == NULL); // dladdr(3) doesn't set dlerror(3). 210 211 // No symbol corresponding to a stack address. 212 ASSERT_EQ(dladdr(&info, &info), 0); // Zero on error, non-zero on success. 213 ASSERT_TRUE(dlerror() == NULL); // dladdr(3) doesn't set dlerror(3). 214} 215 216// Our dynamic linker doesn't support GNU hash tables. 217#if defined(__BIONIC__) 218// GNU-style ELF hash tables are incompatible with the MIPS ABI. 219// MIPS requires .dynsym to be sorted to match the GOT but GNU-style requires sorting by hash code. 220#if !defined(__mips__) 221TEST(dlfcn, dlopen_library_with_only_gnu_hash) { 222 dlerror(); // Clear any pending errors. 223 void* handle = dlopen("no-elf-hash-table-library.so", RTLD_NOW); 224 ASSERT_TRUE(handle == NULL); 225 ASSERT_STREQ("dlopen failed: empty/missing DT_HASH in \"no-elf-hash-table-library.so\" (built with --hash-style=gnu?)", dlerror()); 226} 227#endif 228#endif 229 230TEST(dlfcn, dlopen_bad_flags) { 231 dlerror(); // Clear any pending errors. 232 void* handle; 233 234#if defined(__GLIBC__) 235 // glibc was smart enough not to define RTLD_NOW as 0, so it can detect missing flags. 236 handle = dlopen(NULL, 0); 237 ASSERT_TRUE(handle == NULL); 238 ASSERT_SUBSTR("invalid", dlerror()); 239#endif 240 241 handle = dlopen(NULL, 0xffffffff); 242 ASSERT_TRUE(handle == NULL); 243 ASSERT_SUBSTR("invalid", dlerror()); 244 245 // glibc actually allows you to choose both RTLD_NOW and RTLD_LAZY at the same time, and so do we. 246 handle = dlopen(NULL, RTLD_NOW|RTLD_LAZY); 247 ASSERT_TRUE(handle != NULL); 248 ASSERT_SUBSTR(NULL, dlerror()); 249} 250 251TEST(dlfcn, rtld_default_unknown_symbol) { 252 void* addr = dlsym(RTLD_DEFAULT, "ANY_UNKNOWN_SYMBOL_NAME"); 253 ASSERT_TRUE(addr == NULL); 254} 255 256TEST(dlfcn, rtld_default_known_symbol) { 257 void* addr = dlsym(RTLD_DEFAULT, "fopen"); 258 ASSERT_TRUE(addr != NULL); 259} 260 261TEST(dlfcn, rtld_next_unknown_symbol) { 262 void* addr = dlsym(RTLD_NEXT, "ANY_UNKNOWN_SYMBOL_NAME"); 263 ASSERT_TRUE(addr == NULL); 264} 265 266TEST(dlfcn, rtld_next_known_symbol) { 267 void* addr = dlsym(RTLD_NEXT, "fopen"); 268 ASSERT_TRUE(addr != NULL); 269} 270 271TEST(dlfcn, dlsym_weak_func) { 272 dlerror(); 273 void* handle = dlopen("libtest_dlsym_weak_func.so",RTLD_NOW); 274 ASSERT_TRUE(handle != NULL); 275 276 int (*weak_func)(); 277 weak_func = reinterpret_cast<int (*)()>(dlsym(handle, "weak_func")); 278 ASSERT_TRUE(weak_func != NULL) << "dlerror: " << dlerror(); 279 EXPECT_EQ(42, weak_func()); 280 dlclose(handle); 281} 282 283TEST(dlfcn, dlopen_symlink) { 284 void* handle1 = dlopen("libdlext_test.so", RTLD_NOW); 285 void* handle2 = dlopen("libdlext_test_v2.so", RTLD_NOW); 286 ASSERT_TRUE(handle1 != NULL); 287 ASSERT_TRUE(handle2 != NULL); 288 ASSERT_EQ(handle1, handle2); 289} 290