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/*
* Copyright (C) 2014 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.
*/
#ifdef LIBC_STATIC
#error NetdClient.cpp should NOT be included in static libc builds.
#endif
#include <async_safe/log.h>
#include "private/NetdClientDispatch.h"
#include <dlfcn.h>
#include <pthread.h>
#include <string.h>
#include <unistd.h>
template <typename FunctionType>
static void netdClientInitFunction(void* handle, const char* symbol, FunctionType* function) {
typedef void (*InitFunctionType)(FunctionType*);
InitFunctionType initFunction = reinterpret_cast<InitFunctionType>(dlsym(handle, symbol));
if (initFunction != NULL) {
initFunction(function);
}
}
static void netdClientInitImpl() {
// Prevent netd from looping back fwmarkd connections to itself. It would work, but it's
// a deadlock hazard and unnecessary overhead for the resolver.
if (getuid() == 0 && strcmp(basename(getprogname()), "netd") == 0) {
async_safe_format_log(ANDROID_LOG_INFO, "netdClient",
"Skipping libnetd_client init since *we* are netd");
return;
}
void* netdClientHandle = dlopen("libnetd_client.so", RTLD_NOW);
if (netdClientHandle == NULL) {
// If the library is not available, it's not an error. We'll just use
// default implementations of functions that it would've overridden.
return;
}
netdClientInitFunction(netdClientHandle, "netdClientInitAccept4",
&__netdClientDispatch.accept4);
netdClientInitFunction(netdClientHandle, "netdClientInitConnect",
&__netdClientDispatch.connect);
netdClientInitFunction(netdClientHandle, "netdClientInitNetIdForResolv",
&__netdClientDispatch.netIdForResolv);
netdClientInitFunction(netdClientHandle, "netdClientInitSocket", &__netdClientDispatch.socket);
netdClientInitFunction(netdClientHandle, "netdClientInitDnsOpenProxy",
&__netdClientDispatch.dnsOpenProxy);
}
static pthread_once_t netdClientInitOnce = PTHREAD_ONCE_INIT;
extern "C" __LIBC_HIDDEN__ void netdClientInit() {
if (pthread_once(&netdClientInitOnce, netdClientInitImpl)) {
async_safe_format_log(ANDROID_LOG_ERROR, "netdClient", "Failed to initialize libnetd_client");
}
}
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