| /* |
| * Copyright (C) 2018 The Android Open Source Project |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * * Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * * Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in |
| * the documentation and/or other materials provided with the |
| * distribution. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
| * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
| * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, |
| * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS |
| * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED |
| * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, |
| * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT |
| * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| * SUCH DAMAGE. |
| */ |
| |
| #include <string> |
| |
| #include <dlfcn.h> |
| #include <errno.h> |
| #include <stdlib.h> |
| #include <string.h> |
| |
| #define LOG_TAG "Netd" |
| #include <log/log.h> |
| |
| #include <netd_resolv/resolv_stub.h> |
| |
| struct ResolvStub RESOLV_STUB; |
| |
| inline constexpr char APEX_LIB64_DIR[] = "/apex/com.android.resolv/lib64"; |
| inline constexpr char APEX_LIB_DIR[] = "/apex/com.android.resolv/lib"; |
| inline constexpr char LIBNAME[] = "libnetd_resolv.so"; |
| |
| template <typename FunctionType> |
| static void resolvStubInitFunction(void* handle, const char* symbol, FunctionType** stubPtr) { |
| void* f = dlsym(handle, symbol); |
| if (f == nullptr) { |
| ALOGE("Can't find symbol %s in %s", symbol, LIBNAME); |
| abort(); |
| } |
| *stubPtr = reinterpret_cast<FunctionType*>(f); |
| } |
| |
| int resolv_stub_init() { |
| void* netdResolvHandle; |
| |
| for (const auto& dir : {APEX_LIB64_DIR, APEX_LIB_DIR}) { |
| std::string path = std::string(dir) + "/" + LIBNAME; |
| netdResolvHandle = dlopen(path.c_str(), RTLD_NOW); |
| if (netdResolvHandle != nullptr) { |
| ALOGI("Loaded resolver library from %s", path.c_str()); |
| break; |
| } |
| ALOGW("dlopen(%s) failed: %s", path.c_str(), strerror(errno)); |
| } |
| |
| if (netdResolvHandle == nullptr) { |
| ALOGE("Fatal: couldn't open libnetd_resolv"); |
| abort(); |
| } |
| |
| #define STR(x) #x |
| #define RESOLV_STUB_LOAD_SYMBOL(x) resolvStubInitFunction(netdResolvHandle, STR(x), &RESOLV_STUB.x) |
| RESOLV_STUB_LOAD_SYMBOL(resolv_has_nameservers); |
| RESOLV_STUB_LOAD_SYMBOL(resolv_init); |
| #undef RESOLV_STUB_LOAD_SYMBOL |
| #undef STR |
| |
| return 0; |
| } |