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/*
* Copyright (C) 2012 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <gtest/gtest.h>
#include <dlfcn.h>
#include <libgen.h>
#include <limits.h>
#include <stdio.h>
#include <stdint.h>
#include <string>
#define ASSERT_SUBSTR(needle, haystack) \
ASSERT_PRED_FORMAT2(::testing::IsSubstring, needle, haystack)
static bool gCalled = false;
extern "C" void DlSymTestFunction() {
gCalled = true;
}
TEST(dlfcn, dlsym_in_self) {
dlerror(); // Clear any pending errors.
void* self = dlopen(NULL, RTLD_NOW);
ASSERT_TRUE(self != NULL);
ASSERT_TRUE(dlerror() == NULL);
void* sym = dlsym(self, "DlSymTestFunction");
ASSERT_TRUE(sym != NULL);
void (*function)() = reinterpret_cast<void(*)()>(sym);
gCalled = false;
function();
ASSERT_TRUE(gCalled);
ASSERT_EQ(0, dlclose(self));
}
TEST(dlfcn, dlopen_failure) {
void* self = dlopen("/does/not/exist", RTLD_NOW);
ASSERT_TRUE(self == NULL);
#if __BIONIC__
ASSERT_STREQ("dlopen failed: library \"/does/not/exist\" not found", dlerror());
#else
ASSERT_STREQ("/does/not/exist: cannot open shared object file: No such file or directory", dlerror());
#endif
}
static void* ConcurrentDlErrorFn(void*) {
dlopen("/child/thread", RTLD_NOW);
return reinterpret_cast<void*>(strdup(dlerror()));
}
TEST(dlfcn, dlerror_concurrent) {
dlopen("/main/thread", RTLD_NOW);
const char* main_thread_error = dlerror();
ASSERT_SUBSTR("/main/thread", main_thread_error);
pthread_t t;
ASSERT_EQ(0, pthread_create(&t, NULL, ConcurrentDlErrorFn, NULL));
void* result;
ASSERT_EQ(0, pthread_join(t, &result));
char* child_thread_error = static_cast<char*>(result);
ASSERT_SUBSTR("/child/thread", child_thread_error);
free(child_thread_error);
ASSERT_SUBSTR("/main/thread", main_thread_error);
}
TEST(dlfcn, dlsym_failures) {
dlerror(); // Clear any pending errors.
void* self = dlopen(NULL, RTLD_NOW);
ASSERT_TRUE(self != NULL);
ASSERT_TRUE(dlerror() == NULL);
void* sym;
// NULL handle.
sym = dlsym(NULL, "test");
ASSERT_TRUE(sym == NULL);
#if __BIONIC__
ASSERT_SUBSTR("dlsym library handle is null", dlerror());
#else
ASSERT_SUBSTR("undefined symbol: test", dlerror()); // glibc isn't specific about the failure.
#endif
// NULL symbol name.
#if __BIONIC__
// glibc marks this parameter non-null and SEGVs if you cheat.
sym = dlsym(self, NULL);
ASSERT_TRUE(sym == NULL);
ASSERT_SUBSTR("", dlerror());
#endif
// Symbol that doesn't exist.
sym = dlsym(self, "ThisSymbolDoesNotExist");
ASSERT_TRUE(sym == NULL);
ASSERT_SUBSTR("undefined symbol: ThisSymbolDoesNotExist", dlerror());
ASSERT_EQ(0, dlclose(self));
}
TEST(dlfcn, dladdr) {
dlerror(); // Clear any pending errors.
void* self = dlopen(NULL, RTLD_NOW);
ASSERT_TRUE(self != NULL);
ASSERT_TRUE(dlerror() == NULL);
void* sym = dlsym(self, "DlSymTestFunction");
ASSERT_TRUE(sym != NULL);
// Deliberately ask dladdr for an address inside a symbol, rather than the symbol base address.
void* addr = reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(sym) + 2);
Dl_info info;
int rc = dladdr(addr, &info);
ASSERT_NE(rc, 0); // Zero on error, non-zero on success.
// Get the name of this executable.
char executable_path[PATH_MAX];
rc = readlink("/proc/self/exe", executable_path, sizeof(executable_path));
ASSERT_NE(rc, -1);
executable_path[rc] = '\0';
std::string executable_name(basename(executable_path));
// The filename should be that of this executable.
// Note that we don't know whether or not we have the full path, so we want an "ends_with" test.
std::string dli_fname(info.dli_fname);
dli_fname = basename(&dli_fname[0]);
ASSERT_EQ(dli_fname, executable_name);
// The symbol name should be the symbol we looked up.
ASSERT_STREQ(info.dli_sname, "DlSymTestFunction");
// The address should be the exact address of the symbol.
ASSERT_EQ(info.dli_saddr, sym);
// Look in /proc/pid/maps to find out what address we were loaded at.
// TODO: factor /proc/pid/maps parsing out into a class and reuse all over bionic.
void* base_address = NULL;
char path[PATH_MAX];
snprintf(path, sizeof(path), "/proc/%d/maps", getpid());
char line[BUFSIZ];
FILE* fp = fopen(path, "r");
ASSERT_TRUE(fp != NULL);
while (fgets(line, sizeof(line), fp) != NULL) {
uintptr_t start = strtoul(line, 0, 16);
line[strlen(line) - 1] = '\0'; // Chomp the '\n'.
char* path = strchr(line, '/');
if (path != NULL && strcmp(executable_path, path) == 0) {
base_address = reinterpret_cast<void*>(start);
break;
}
}
fclose(fp);
// The base address should be the address we were loaded at.
ASSERT_EQ(info.dli_fbase, base_address);
ASSERT_EQ(0, dlclose(self));
}
TEST(dlfcn, dladdr_invalid) {
Dl_info info;
dlerror(); // Clear any pending errors.
// No symbol corresponding to NULL.
ASSERT_EQ(dladdr(NULL, &info), 0); // Zero on error, non-zero on success.
ASSERT_TRUE(dlerror() == NULL); // dladdr(3) doesn't set dlerror(3).
// No symbol corresponding to a stack address.
ASSERT_EQ(dladdr(&info, &info), 0); // Zero on error, non-zero on success.
ASSERT_TRUE(dlerror() == NULL); // dladdr(3) doesn't set dlerror(3).
}
// Our dynamic linker doesn't support GNU hash tables.
#if defined(__BIONIC__)
// GNU-style ELF hash tables are incompatible with the MIPS ABI.
// MIPS requires .dynsym to be sorted to match the GOT but GNU-style requires sorting by hash code.
#if !defined(__mips__)
TEST(dlfcn, dlopen_library_with_only_gnu_hash) {
dlerror(); // Clear any pending errors.
void* handle = dlopen("no-elf-hash-table-library.so", RTLD_NOW);
ASSERT_TRUE(handle == NULL);
ASSERT_STREQ("dlopen failed: empty/missing DT_HASH in \"no-elf-hash-table-library.so\" (built with --hash-style=gnu?)", dlerror());
}
#endif
#endif
TEST(dlfcn, dlopen_bad_flags) {
dlerror(); // Clear any pending errors.
void* handle;
#ifdef __GLIBC__
// glibc was smart enough not to define RTLD_NOW as 0, so it can detect missing flags.
handle = dlopen(NULL, 0);
ASSERT_TRUE(handle == NULL);
ASSERT_SUBSTR("invalid", dlerror());
#endif
handle = dlopen(NULL, 0xffffffff);
ASSERT_TRUE(handle == NULL);
ASSERT_SUBSTR("invalid", dlerror());
// glibc actually allows you to choose both RTLD_NOW and RTLD_LAZY at the same time, and so do we.
handle = dlopen(NULL, RTLD_NOW|RTLD_LAZY);
ASSERT_TRUE(handle != NULL);
ASSERT_SUBSTR(NULL, dlerror());
}
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