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/*
* Copyright (C) 2015 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 "adb_listeners.h"
#include <stdio.h>
#include <stdlib.h>
#include <algorithm>
#include <list>
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
#include <android-base/thread_annotations.h>
#include <cutils/sockets.h>
#include "socket_spec.h"
#include "sysdeps.h"
#include "transport.h"
// A listener is an entity which binds to a local port and, upon receiving a connection on that
// port, creates an asocket to connect the new local connection to a specific remote service.
//
// TODO: some listeners read from the new connection to determine what exact service to connect to
// on the far side.
class alistener {
public:
alistener(const std::string& _local_name, const std::string& _connect_to);
~alistener();
fdevent fde;
int fd = -1;
std::string local_name;
std::string connect_to;
atransport* transport = nullptr;
adisconnect disconnect;
private:
DISALLOW_COPY_AND_ASSIGN(alistener);
};
alistener::alistener(const std::string& _local_name, const std::string& _connect_to)
: local_name(_local_name), connect_to(_connect_to) {
}
alistener::~alistener() {
// Closes the corresponding fd.
fdevent_remove(&fde);
if (transport) {
transport->RemoveDisconnect(&disconnect);
}
}
// listener_list retains ownership of all created alistener objects. Removing an alistener from
// this list will cause it to be deleted.
static auto& listener_list_mutex = *new std::mutex();
typedef std::list<std::unique_ptr<alistener>> ListenerList;
static ListenerList& listener_list GUARDED_BY(listener_list_mutex) = *new ListenerList();
static void ss_listener_event_func(int _fd, unsigned ev, void *_l) {
if (ev & FDE_READ) {
int fd = adb_socket_accept(_fd, nullptr, nullptr);
if (fd < 0) return;
int rcv_buf_size = CHUNK_SIZE;
adb_setsockopt(fd, SOL_SOCKET, SO_RCVBUF, &rcv_buf_size, sizeof(rcv_buf_size));
asocket* s = create_local_socket(fd);
if (s) {
connect_to_smartsocket(s);
return;
}
adb_close(fd);
}
}
static void listener_event_func(int _fd, unsigned ev, void* _l)
{
alistener* listener = reinterpret_cast<alistener*>(_l);
asocket *s;
if (ev & FDE_READ) {
int fd = adb_socket_accept(_fd, nullptr, nullptr);
if (fd < 0) {
return;
}
s = create_local_socket(fd);
if (s) {
s->transport = listener->transport;
connect_to_remote(s, listener->connect_to.c_str());
return;
}
adb_close(fd);
}
}
// Called as a transport disconnect function. |arg| is the raw alistener*.
static void listener_disconnect(void* arg, atransport*) EXCLUDES(listener_list_mutex) {
std::lock_guard<std::mutex> lock(listener_list_mutex);
for (auto iter = listener_list.begin(); iter != listener_list.end(); ++iter) {
if (iter->get() == arg) {
(*iter)->transport = nullptr;
listener_list.erase(iter);
return;
}
}
}
// Write the list of current listeners (network redirections) into a string.
std::string format_listeners() EXCLUDES(listener_list_mutex) {
std::lock_guard<std::mutex> lock(listener_list_mutex);
std::string result;
for (auto& l : listener_list) {
// Ignore special listeners like those for *smartsocket*
if (l->connect_to[0] == '*') {
continue;
}
// <device-serial> " " <local-name> " " <remote-name> "\n"
// Entries from "adb reverse" have no serial.
android::base::StringAppendF(&result, "%s %s %s\n",
l->transport->serial ? l->transport->serial : "(reverse)",
l->local_name.c_str(), l->connect_to.c_str());
}
return result;
}
InstallStatus remove_listener(const char* local_name, atransport* transport)
EXCLUDES(listener_list_mutex) {
std::lock_guard<std::mutex> lock(listener_list_mutex);
for (auto iter = listener_list.begin(); iter != listener_list.end(); ++iter) {
if (local_name == (*iter)->local_name) {
listener_list.erase(iter);
return INSTALL_STATUS_OK;
}
}
return INSTALL_STATUS_LISTENER_NOT_FOUND;
}
void remove_all_listeners() EXCLUDES(listener_list_mutex) {
std::lock_guard<std::mutex> lock(listener_list_mutex);
auto iter = listener_list.begin();
while (iter != listener_list.end()) {
// Never remove smart sockets.
if ((*iter)->connect_to[0] == '*') {
++iter;
} else {
iter = listener_list.erase(iter);
}
}
}
void close_smartsockets() EXCLUDES(listener_list_mutex) {
std::lock_guard<std::mutex> lock(listener_list_mutex);
auto pred = [](const std::unique_ptr<alistener>& listener) {
return listener->local_name == "*smartsocket*";
};
listener_list.remove_if(pred);
}
InstallStatus install_listener(const std::string& local_name, const char* connect_to,
atransport* transport, int no_rebind, int* resolved_tcp_port,
std::string* error) EXCLUDES(listener_list_mutex) {
std::lock_guard<std::mutex> lock(listener_list_mutex);
for (auto& l : listener_list) {
if (local_name == l->local_name) {
// Can't repurpose a smartsocket.
if(l->connect_to[0] == '*') {
*error = "cannot repurpose smartsocket";
return INSTALL_STATUS_INTERNAL_ERROR;
}
// Can't repurpose a listener if 'no_rebind' is true.
if (no_rebind) {
*error = "cannot rebind";
return INSTALL_STATUS_CANNOT_REBIND;
}
l->connect_to = connect_to;
if (l->transport != transport) {
l->transport->RemoveDisconnect(&l->disconnect);
l->transport = transport;
l->transport->AddDisconnect(&l->disconnect);
}
return INSTALL_STATUS_OK;
}
}
std::unique_ptr<alistener> listener(new alistener(local_name, connect_to));
int resolved = 0;
listener->fd = socket_spec_listen(listener->local_name, error, &resolved);
if (listener->fd < 0) {
return INSTALL_STATUS_CANNOT_BIND;
}
// If the caller requested port 0, update the listener name with the resolved port.
if (resolved != 0) {
listener->local_name = android::base::StringPrintf("tcp:%d", resolved);
if (resolved_tcp_port) {
*resolved_tcp_port = resolved;
}
}
close_on_exec(listener->fd);
if (listener->connect_to == "*smartsocket*") {
fdevent_install(&listener->fde, listener->fd, ss_listener_event_func, listener.get());
} else {
fdevent_install(&listener->fde, listener->fd, listener_event_func, listener.get());
}
fdevent_set(&listener->fde, FDE_READ);
listener->transport = transport;
if (transport) {
listener->disconnect.opaque = listener.get();
listener->disconnect.func = listener_disconnect;
transport->AddDisconnect(&listener->disconnect);
}
listener_list.push_back(std::move(listener));
return INSTALL_STATUS_OK;
}