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android_system_core/adb/client/usb_libusb.cpp

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/*
* Copyright (C) 2016 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 "usb.h"
#include "sysdeps.h"
#include <stdint.h>
#include <stdlib.h>
#include <atomic>
#include <chrono>
#include <condition_variable>
#include <memory>
#include <mutex>
#include <string>
#include <thread>
#include <unordered_map>
#include <libusb/libusb.h>
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
#include "adb.h"
#include "adb_utils.h"
#include "transport.h"
#include "usb.h"
using android::base::StringPrintf;
// RAII wrappers for libusb.
struct ConfigDescriptorDeleter {
void operator()(libusb_config_descriptor* desc) {
libusb_free_config_descriptor(desc);
}
};
using unique_config_descriptor = std::unique_ptr<libusb_config_descriptor, ConfigDescriptorDeleter>;
struct DeviceHandleDeleter {
void operator()(libusb_device_handle* h) {
libusb_close(h);
}
};
using unique_device_handle = std::unique_ptr<libusb_device_handle, DeviceHandleDeleter>;
struct transfer_info {
transfer_info(const char* name, uint16_t zero_mask, bool is_bulk_out)
: name(name),
transfer(libusb_alloc_transfer(0)),
is_bulk_out(is_bulk_out),
zero_mask(zero_mask) {}
~transfer_info() {
libusb_free_transfer(transfer);
}
const char* name;
libusb_transfer* transfer;
bool is_bulk_out;
bool transfer_complete;
std::condition_variable cv;
std::mutex mutex;
uint16_t zero_mask;
void Notify() {
LOG(DEBUG) << "notifying " << name << " transfer complete";
transfer_complete = true;
cv.notify_one();
}
};
namespace libusb {
struct usb_handle : public ::usb_handle {
usb_handle(const std::string& device_address, const std::string& serial,
unique_device_handle&& device_handle, uint8_t interface, uint8_t bulk_in,
uint8_t bulk_out, size_t zero_mask, size_t max_packet_size)
: device_address(device_address),
serial(serial),
closing(false),
device_handle(device_handle.release()),
read("read", zero_mask, false),
write("write", zero_mask, true),
interface(interface),
bulk_in(bulk_in),
bulk_out(bulk_out),
max_packet_size(max_packet_size) {}
~usb_handle() {
Close();
}
void Close() {
std::unique_lock<std::mutex> lock(device_handle_mutex);
// Cancelling transfers will trigger more Closes, so make sure this only happens once.
if (closing) {
return;
}
closing = true;
// Make sure that no new transfers come in.
libusb_device_handle* handle = device_handle;
if (!handle) {
return;
}
device_handle = nullptr;
// Cancel already dispatched transfers.
libusb_cancel_transfer(read.transfer);
libusb_cancel_transfer(write.transfer);
libusb_release_interface(handle, interface);
libusb_close(handle);
}
std::string device_address;
std::string serial;
std::atomic<bool> closing;
std::mutex device_handle_mutex;
libusb_device_handle* device_handle;
transfer_info read;
transfer_info write;
uint8_t interface;
uint8_t bulk_in;
uint8_t bulk_out;
size_t max_packet_size;
};
static auto& usb_handles = *new std::unordered_map<std::string, std::unique_ptr<usb_handle>>();
static auto& usb_handles_mutex = *new std::mutex();
static libusb_hotplug_callback_handle hotplug_handle;
static std::string get_device_address(libusb_device* device) {
return StringPrintf("usb:%d:%d", libusb_get_bus_number(device),
libusb_get_device_address(device));
}
#if defined(__linux__)
static std::string get_device_serial_path(libusb_device* device) {
uint8_t ports[7];
int port_count = libusb_get_port_numbers(device, ports, 7);
if (port_count < 0) return "";
std::string path =
StringPrintf("/sys/bus/usb/devices/%d-%d", libusb_get_bus_number(device), ports[0]);
for (int port = 1; port < port_count; ++port) {
path += StringPrintf(".%d", ports[port]);
}
path += "/serial";
return path;
}
static std::string get_device_dev_path(libusb_device* device) {
uint8_t ports[7];
int port_count = libusb_get_port_numbers(device, ports, 7);
if (port_count < 0) return "";
return StringPrintf("/dev/bus/usb/%03u/%03u", libusb_get_bus_number(device), ports[0]);
}
#endif
static bool endpoint_is_output(uint8_t endpoint) {
return (endpoint & LIBUSB_ENDPOINT_DIR_MASK) == LIBUSB_ENDPOINT_OUT;
}
static bool should_perform_zero_transfer(uint8_t endpoint, size_t write_length, uint16_t zero_mask) {
return endpoint_is_output(endpoint) && write_length != 0 && zero_mask != 0 &&
(write_length & zero_mask) == 0;
}
static void process_device(libusb_device* device) {
std::string device_address = get_device_address(device);
std::string device_serial;
// Figure out if we want to open the device.
libusb_device_descriptor device_desc;
int rc = libusb_get_device_descriptor(device, &device_desc);
if (rc != 0) {
LOG(WARNING) << "failed to get device descriptor for device at " << device_address << ": "
<< libusb_error_name(rc);
return;
}
if (device_desc.bDeviceClass != LIBUSB_CLASS_PER_INTERFACE) {
// Assume that all Android devices have the device class set to per interface.
// TODO: Is this assumption valid?
LOG(VERBOSE) << "skipping device with incorrect class at " << device_address;
return;
}
libusb_config_descriptor* config_raw;
rc = libusb_get_active_config_descriptor(device, &config_raw);
if (rc != 0) {
LOG(WARNING) << "failed to get active config descriptor for device at " << device_address
<< ": " << libusb_error_name(rc);
return;
}
const unique_config_descriptor config(config_raw);
// Use size_t for interface_num so <iostream>s don't mangle it.
size_t interface_num;
uint16_t zero_mask = 0;
uint8_t bulk_in = 0, bulk_out = 0;
size_t packet_size = 0;
bool found_adb = false;
for (interface_num = 0; interface_num < config->bNumInterfaces; ++interface_num) {
const libusb_interface& interface = config->interface[interface_num];
if (interface.num_altsetting != 1) {
// Assume that interfaces with alternate settings aren't adb interfaces.
// TODO: Is this assumption valid?
LOG(VERBOSE) << "skipping interface with incorrect num_altsetting at " << device_address
<< " (interface " << interface_num << ")";
continue;
}
const libusb_interface_descriptor& interface_desc = interface.altsetting[0];
if (!is_adb_interface(interface_desc.bInterfaceClass, interface_desc.bInterfaceSubClass,
interface_desc.bInterfaceProtocol)) {
LOG(VERBOSE) << "skipping non-adb interface at " << device_address << " (interface "
<< interface_num << ")";
continue;
}
LOG(VERBOSE) << "found potential adb interface at " << device_address << " (interface "
<< interface_num << ")";
bool found_in = false;
bool found_out = false;
for (size_t endpoint_num = 0; endpoint_num < interface_desc.bNumEndpoints; ++endpoint_num) {
const auto& endpoint_desc = interface_desc.endpoint[endpoint_num];
const uint8_t endpoint_addr = endpoint_desc.bEndpointAddress;
const uint8_t endpoint_attr = endpoint_desc.bmAttributes;
const uint8_t transfer_type = endpoint_attr & LIBUSB_TRANSFER_TYPE_MASK;
if (transfer_type != LIBUSB_TRANSFER_TYPE_BULK) {
continue;
}
if (endpoint_is_output(endpoint_addr) && !found_out) {
found_out = true;
bulk_out = endpoint_addr;
zero_mask = endpoint_desc.wMaxPacketSize - 1;
} else if (!endpoint_is_output(endpoint_addr) && !found_in) {
found_in = true;
bulk_in = endpoint_addr;
}
size_t endpoint_packet_size = endpoint_desc.wMaxPacketSize;
CHECK(endpoint_packet_size != 0);
if (packet_size == 0) {
packet_size = endpoint_packet_size;
} else {
CHECK(packet_size == endpoint_packet_size);
}
}
if (found_in && found_out) {
found_adb = true;
break;
} else {
LOG(VERBOSE) << "rejecting potential adb interface at " << device_address
<< "(interface " << interface_num << "): missing bulk endpoints "
<< "(found_in = " << found_in << ", found_out = " << found_out << ")";
}
}
if (!found_adb) {
LOG(VERBOSE) << "skipping device with no adb interfaces at " << device_address;
return;
}
{
std::unique_lock<std::mutex> lock(usb_handles_mutex);
if (usb_handles.find(device_address) != usb_handles.end()) {
LOG(VERBOSE) << "device at " << device_address
<< " has already been registered, skipping";
return;
}
}
bool writable = true;
libusb_device_handle* handle_raw = nullptr;
rc = libusb_open(device, &handle_raw);
unique_device_handle handle(handle_raw);
if (rc == 0) {
LOG(DEBUG) << "successfully opened adb device at " << device_address << ", "
<< StringPrintf("bulk_in = %#x, bulk_out = %#x", bulk_in, bulk_out);
device_serial.resize(255);
rc = libusb_get_string_descriptor_ascii(handle_raw, device_desc.iSerialNumber,
reinterpret_cast<unsigned char*>(&device_serial[0]),
device_serial.length());
if (rc == 0) {
LOG(WARNING) << "received empty serial from device at " << device_address;
return;
} else if (rc < 0) {
LOG(WARNING) << "failed to get serial from device at " << device_address
<< libusb_error_name(rc);
return;
}
device_serial.resize(rc);
// WARNING: this isn't released via RAII.
rc = libusb_claim_interface(handle.get(), interface_num);
if (rc != 0) {
LOG(WARNING) << "failed to claim adb interface for device '" << device_serial << "'"
<< libusb_error_name(rc);
return;
}
for (uint8_t endpoint : {bulk_in, bulk_out}) {
rc = libusb_clear_halt(handle.get(), endpoint);
if (rc != 0) {
LOG(WARNING) << "failed to clear halt on device '" << device_serial
<< "' endpoint 0x" << std::hex << endpoint << ": "
<< libusb_error_name(rc);
libusb_release_interface(handle.get(), interface_num);
return;
}
}
} else {
LOG(WARNING) << "failed to open usb device at " << device_address << ": "
<< libusb_error_name(rc);
writable = false;
#if defined(__linux__)
// libusb doesn't think we should be messing around with devices we don't have
// write access to, but Linux at least lets us get the serial number anyway.
if (!android::base::ReadFileToString(get_device_serial_path(device), &device_serial)) {
// We don't actually want to treat an unknown serial as an error because
// devices aren't able to communicate a serial number in early bringup.
// http://b/20883914
device_serial = "unknown";
}
device_serial = android::base::Trim(device_serial);
#else
// On Mac OS and Windows, we're screwed. But I don't think this situation actually
// happens on those OSes.
return;
#endif
}
std::unique_ptr<usb_handle> result(new usb_handle(device_address, device_serial,
std::move(handle), interface_num, bulk_in,
bulk_out, zero_mask, packet_size));
usb_handle* usb_handle_raw = result.get();
{
std::unique_lock<std::mutex> lock(usb_handles_mutex);
usb_handles[device_address] = std::move(result);
register_usb_transport(usb_handle_raw, device_serial.c_str(), device_address.c_str(),
writable);
}
LOG(INFO) << "registered new usb device '" << device_serial << "'";
}
static std::atomic<int> connecting_devices(0);
static void device_connected(libusb_device* device) {
#if defined(__linux__)
// Android's host linux libusb uses netlink instead of udev for device hotplug notification,
// which means we can get hotplug notifications before udev has updated ownership/perms on the
// device. Since we're not going to be able to link against the system's libudev any time soon,
// hack around this by inserting a sleep.
auto thread = std::thread([device]() {
std::string device_path = get_device_dev_path(device);
std::this_thread::sleep_for(std::chrono::seconds(1));
process_device(device);
if (--connecting_devices == 0) {
adb_notify_device_scan_complete();
}
});
thread.detach();
#else
process_device(device);
#endif
}
static void device_disconnected(libusb_device* device) {
std::string device_address = get_device_address(device);
LOG(INFO) << "device disconnected: " << device_address;
std::unique_lock<std::mutex> lock(usb_handles_mutex);
auto it = usb_handles.find(device_address);
if (it != usb_handles.end()) {
if (!it->second->device_handle) {
// If the handle is null, we were never able to open the device.
// Temporarily release the usb handles mutex to avoid deadlock.
std::unique_ptr<usb_handle> handle = std::move(it->second);
usb_handles.erase(it);
lock.unlock();
unregister_usb_transport(handle.get());
lock.lock();
} else {
// Closure of the transport will erase the usb_handle.
}
}
}
static auto& hotplug_queue = *new BlockingQueue<std::pair<libusb_hotplug_event, libusb_device*>>();
static void hotplug_thread() {
adb_thread_setname("libusb hotplug");
while (true) {
hotplug_queue.PopAll([](std::pair<libusb_hotplug_event, libusb_device*> pair) {
libusb_hotplug_event event = pair.first;
libusb_device* device = pair.second;
if (event == LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED) {
device_connected(device);
} else if (event == LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT) {
device_disconnected(device);
}
});
}
}
static LIBUSB_CALL int hotplug_callback(libusb_context*, libusb_device* device,
libusb_hotplug_event event, void*) {
// We're called with the libusb lock taken. Call these on a separate thread outside of this
// function so that the usb_handle mutex is always taken before the libusb mutex.
static std::once_flag once;
std::call_once(once, []() { std::thread(hotplug_thread).detach(); });
if (event == LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED) {
++connecting_devices;
}
hotplug_queue.Push({event, device});
return 0;
}
void usb_init() {
LOG(DEBUG) << "initializing libusb...";
int rc = libusb_init(nullptr);
if (rc != 0) {
LOG(FATAL) << "failed to initialize libusb: " << libusb_error_name(rc);
}
// Register the hotplug callback.
rc = libusb_hotplug_register_callback(
nullptr, static_cast<libusb_hotplug_event>(LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED |
LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT),
LIBUSB_HOTPLUG_ENUMERATE, LIBUSB_HOTPLUG_MATCH_ANY, LIBUSB_HOTPLUG_MATCH_ANY,
LIBUSB_CLASS_PER_INTERFACE, hotplug_callback, nullptr, &hotplug_handle);
if (rc != LIBUSB_SUCCESS) {
LOG(FATAL) << "failed to register libusb hotplug callback";
}
// Spawn a thread for libusb_handle_events.
std::thread([]() {
adb_thread_setname("libusb");
while (true) {
libusb_handle_events(nullptr);
}
}).detach();
}
void usb_cleanup() {
libusb_hotplug_deregister_callback(nullptr, hotplug_handle);
}
static LIBUSB_CALL void transfer_callback(libusb_transfer* transfer) {
transfer_info* info = static_cast<transfer_info*>(transfer->user_data);
LOG(DEBUG) << info->name << " transfer callback entered";
// Make sure that the original submitter has made it to the condition_variable wait.
std::unique_lock<std::mutex> lock(info->mutex);
LOG(DEBUG) << info->name << " callback successfully acquired lock";
if (transfer->status != LIBUSB_TRANSFER_COMPLETED) {
LOG(WARNING) << info->name << " transfer failed: " << libusb_error_name(transfer->status);
info->Notify();
return;
}
// usb_read() can return when receiving some data.
if (info->is_bulk_out && transfer->actual_length != transfer->length) {
LOG(DEBUG) << info->name << " transfer incomplete, resubmitting";
transfer->length -= transfer->actual_length;
transfer->buffer += transfer->actual_length;
int rc = libusb_submit_transfer(transfer);
if (rc != 0) {
LOG(WARNING) << "failed to submit " << info->name
<< " transfer: " << libusb_error_name(rc);
transfer->status = LIBUSB_TRANSFER_ERROR;
info->Notify();
}
return;
}
if (should_perform_zero_transfer(transfer->endpoint, transfer->length, info->zero_mask)) {
LOG(DEBUG) << "submitting zero-length write";
transfer->length = 0;
int rc = libusb_submit_transfer(transfer);
if (rc != 0) {
LOG(WARNING) << "failed to submit zero-length write: " << libusb_error_name(rc);
transfer->status = LIBUSB_TRANSFER_ERROR;
info->Notify();
}
return;
}
LOG(VERBOSE) << info->name << "transfer fully complete";
info->Notify();
}
// Dispatch a libusb transfer, unlock |device_lock|, and then wait for the result.
static int perform_usb_transfer(usb_handle* h, transfer_info* info,
std::unique_lock<std::mutex> device_lock) {
libusb_transfer* transfer = info->transfer;
transfer->user_data = info;
transfer->callback = transfer_callback;
LOG(DEBUG) << "locking " << info->name << " transfer_info mutex";
std::unique_lock<std::mutex> lock(info->mutex);
info->transfer_complete = false;
LOG(DEBUG) << "submitting " << info->name << " transfer";
int rc = libusb_submit_transfer(transfer);
if (rc != 0) {
LOG(WARNING) << "failed to submit " << info->name << " transfer: " << libusb_error_name(rc);
errno = EIO;
return -1;
}
LOG(DEBUG) << info->name << " transfer successfully submitted";
device_lock.unlock();
info->cv.wait(lock, [info]() { return info->transfer_complete; });
if (transfer->status != 0) {
errno = EIO;
return -1;
}
return 0;
}
int usb_write(usb_handle* h, const void* d, int len) {
LOG(DEBUG) << "usb_write of length " << len;
std::unique_lock<std::mutex> lock(h->device_handle_mutex);
if (!h->device_handle) {
errno = EIO;
return -1;
}
transfer_info* info = &h->write;
info->transfer->dev_handle = h->device_handle;
info->transfer->flags = 0;
info->transfer->endpoint = h->bulk_out;
info->transfer->type = LIBUSB_TRANSFER_TYPE_BULK;
info->transfer->length = len;
info->transfer->buffer = reinterpret_cast<unsigned char*>(const_cast<void*>(d));
info->transfer->num_iso_packets = 0;
int rc = perform_usb_transfer(h, info, std::move(lock));
LOG(DEBUG) << "usb_write(" << len << ") = " << rc;
return info->transfer->actual_length;
}
int usb_read(usb_handle* h, void* d, int len) {
LOG(DEBUG) << "usb_read of length " << len;
std::unique_lock<std::mutex> lock(h->device_handle_mutex);
if (!h->device_handle) {
errno = EIO;
return -1;
}
transfer_info* info = &h->read;
info->transfer->dev_handle = h->device_handle;
info->transfer->flags = 0;
info->transfer->endpoint = h->bulk_in;
info->transfer->type = LIBUSB_TRANSFER_TYPE_BULK;
info->transfer->length = len;
info->transfer->buffer = reinterpret_cast<unsigned char*>(d);
info->transfer->num_iso_packets = 0;
int rc = perform_usb_transfer(h, info, std::move(lock));
LOG(DEBUG) << "usb_read(" << len << ") = " << rc << ", actual_length "
<< info->transfer->actual_length;
if (rc < 0) {
return rc;
}
return info->transfer->actual_length;
}
int usb_close(usb_handle* h) {
std::unique_lock<std::mutex> lock(usb_handles_mutex);
auto it = usb_handles.find(h->device_address);
if (it == usb_handles.end()) {
LOG(FATAL) << "attempted to close unregistered usb_handle for '" << h->serial << "'";
}
usb_handles.erase(h->device_address);
return 0;
}
void usb_kick(usb_handle* h) {
h->Close();
}
size_t usb_get_max_packet_size(usb_handle* h) {
CHECK(h->max_packet_size != 0);
return h->max_packet_size;
}
} // namespace libusb
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