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/*
* Copyright (C) 2019 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 "adbconnection/server.h"
#include <sys/epoll.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <unistd.h>
#include <algorithm>
#include <array>
#include <vector>
#include <android-base/logging.h>
#include <android-base/unique_fd.h>
using android::base::unique_fd;
#define JDWP_CONTROL_NAME "\0jdwp-control"
#define JDWP_CONTROL_NAME_LEN (sizeof(JDWP_CONTROL_NAME) - 1)
static_assert(JDWP_CONTROL_NAME_LEN <= sizeof(reinterpret_cast<sockaddr_un*>(0)->sun_path));
// Listen for incoming jdwp clients forever.
void adbconnection_listen(void (*callback)(int fd, pid_t pid)) {
sockaddr_un addr = {};
socklen_t addrlen = JDWP_CONTROL_NAME_LEN + sizeof(addr.sun_family);
addr.sun_family = AF_UNIX;
memcpy(addr.sun_path, JDWP_CONTROL_NAME, JDWP_CONTROL_NAME_LEN);
unique_fd s(socket(AF_UNIX, SOCK_SEQPACKET | SOCK_NONBLOCK | SOCK_CLOEXEC, 0));
if (s < 0) {
PLOG(ERROR) << "failed to create JDWP control socket";
return;
}
if (bind(s.get(), reinterpret_cast<sockaddr*>(&addr), addrlen) < 0) {
PLOG(ERROR) << "failed to bind JDWP control socket";
return;
}
if (listen(s.get(), 4) < 0) {
PLOG(ERROR) << "failed to listen on JDWP control socket";
return;
}
std::vector<unique_fd> pending_connections;
unique_fd epfd(epoll_create1(EPOLL_CLOEXEC));
std::array<epoll_event, 16> events;
events[0].events = EPOLLIN;
events[0].data.fd = -1;
if (epoll_ctl(epfd.get(), EPOLL_CTL_ADD, s.get(), &events[0]) != 0) {
LOG(FATAL) << "failed to register event with epoll fd";
}
while (true) {
int epoll_rc = TEMP_FAILURE_RETRY(epoll_wait(epfd.get(), events.data(), events.size(), -1));
if (epoll_rc == -1) {
PLOG(FATAL) << "epoll_wait failed";
}
for (int i = 0; i < epoll_rc; ++i) {
const epoll_event& event = events[i];
if (event.data.fd == -1) {
unique_fd client(
TEMP_FAILURE_RETRY(accept4(s.get(), nullptr, nullptr, SOCK_NONBLOCK | SOCK_CLOEXEC)));
if (client == -1) {
PLOG(WARNING) << "failed to accept client on JDWP control socket";
continue;
}
epoll_event register_event;
register_event.events = EPOLLIN;
register_event.data.fd = client.get();
if (epoll_ctl(epfd.get(), EPOLL_CTL_ADD, client.get(), ®ister_event) != 0) {
PLOG(FATAL) << "failed to register JDWP client with epoll";
}
pending_connections.emplace_back(std::move(client));
} else {
// n^2, but the backlog should be short.
auto it = std::find_if(pending_connections.begin(), pending_connections.end(),
[&](const unique_fd& fd) { return fd.get() == event.data.fd; });
if (it == pending_connections.end()) {
LOG(FATAL) << "failed to find JDWP client (" << event.data.fd
<< ") in pending connections";
}
// Massively oversized buffer: we're expecting an int32_t from the other end.
char buf[32];
int rc = TEMP_FAILURE_RETRY(recv(it->get(), buf, sizeof(buf), MSG_DONTWAIT));
if (rc != 4) {
LOG(ERROR) << "received data of incorrect size from JDWP client: read " << rc
<< ", expected 4";
} else {
int32_t pid;
memcpy(&pid, buf, sizeof(pid));
callback(it->release(), static_cast<pid_t>(pid));
}
if (epoll_ctl(epfd.get(), EPOLL_CTL_DEL, event.data.fd, nullptr) != 0) {
LOG(FATAL) << "failed to delete fd from JDWP epoll fd";
}
pending_connections.erase(it);
}
}
}
}
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