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