Migrate IUsb to AIDL
This change migrates android.hardware.usb.IUsb to AIDL and
adds the default implementation.
Compared to the HIDL interface, AIDL based interface adds
transactionId argument to each of the interface method which
is used while invoking the corresponding callback.
Bug: 200993386
Bug: 199357330
Test: Ran new hal implementation on Pixel. Yet to run VTS.
Change-Id: Id8aa40682d4c4b435c63b3ae249b176276dbb31d
diff --git a/usb/aidl/default/Usb.cpp b/usb/aidl/default/Usb.cpp
new file mode 100644
index 0000000..1105376
--- /dev/null
+++ b/usb/aidl/default/Usb.cpp
@@ -0,0 +1,693 @@
+/*
+ * Copyright (C) 2021 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.
+ */
+
+#define LOG_TAG "android.hardware.usb.aidl-service"
+
+#include <aidl/android/hardware/usb/PortRole.h>
+#include <android-base/logging.h>
+#include <android-base/properties.h>
+#include <android-base/strings.h>
+#include <assert.h>
+#include <dirent.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <chrono>
+#include <regex>
+#include <thread>
+#include <unordered_map>
+
+#include <cutils/uevent.h>
+#include <sys/epoll.h>
+#include <utils/Errors.h>
+#include <utils/StrongPointer.h>
+
+#include "Usb.h"
+
+using android::base::GetProperty;
+using android::base::Trim;
+
+namespace aidl {
+namespace android {
+namespace hardware {
+namespace usb {
+
+constexpr char kTypecPath[] = "/sys/class/typec/";
+constexpr char kDataRoleNode[] = "/data_role";
+constexpr char kPowerRoleNode[] = "/power_role";
+
+// Set by the signal handler to destroy the thread
+volatile bool destroyThread;
+
+void queryVersionHelper(android::hardware::usb::Usb *usb,
+ std::vector<PortStatus> *currentPortStatus);
+
+ScopedAStatus Usb::enableUsbData(const string& in_portName, bool in_enable, int64_t in_transactionId) {
+ std::vector<PortStatus> currentPortStatus;
+
+ pthread_mutex_lock(&mLock);
+ if (mCallback != NULL) {
+ ScopedAStatus ret = mCallback->notifyEnableUsbDataStatus(
+ in_portName, true, in_enable ? Status::SUCCESS : Status::ERROR, in_transactionId);
+ if (!ret.isOk())
+ ALOGE("notifyEnableUsbDataStatus error %s", ret.getDescription().c_str());
+ } else {
+ ALOGE("Not notifying the userspace. Callback is not set");
+ }
+ pthread_mutex_unlock(&mLock);
+ queryVersionHelper(this, ¤tPortStatus);
+
+ return ScopedAStatus::ok();
+}
+
+Status queryMoistureDetectionStatus(std::vector<PortStatus> *currentPortStatus) {
+ string enabled, status, path, DetectedPath;
+
+ for (int i = 0; i < currentPortStatus->size(); i++) {
+ (*currentPortStatus)[i].supportedContaminantProtectionModes
+ .push_back(ContaminantProtectionMode::NONE);
+ (*currentPortStatus)[i].contaminantProtectionStatus
+ = ContaminantProtectionStatus::NONE;
+ (*currentPortStatus)[i].contaminantDetectionStatus
+ = ContaminantDetectionStatus::NOT_SUPPORTED;
+ (*currentPortStatus)[i].supportsEnableContaminantPresenceDetection = false;
+ (*currentPortStatus)[i].supportsEnableContaminantPresenceProtection = false;
+ }
+
+ return Status::SUCCESS;
+}
+
+string appendRoleNodeHelper(const string &portName, PortRole::Tag tag) {
+ string node(kTypecPath + portName);
+
+ switch (tag) {
+ case PortRole::dataRole:
+ return node + kDataRoleNode;
+ case PortRole::powerRole:
+ return node + kPowerRoleNode;
+ case PortRole::mode:
+ return node + "/port_type";
+ default:
+ return "";
+ }
+}
+
+string convertRoletoString(PortRole role) {
+ if (role.getTag() == PortRole::powerRole) {
+ if (role.get<PortRole::powerRole>() == PortPowerRole::SOURCE)
+ return "source";
+ else if (role.get<PortRole::powerRole>() == PortPowerRole::SINK)
+ return "sink";
+ } else if (role.getTag() == PortRole::dataRole) {
+ if (role.get<PortRole::dataRole>() == PortDataRole::HOST)
+ return "host";
+ if (role.get<PortRole::dataRole>() == PortDataRole::DEVICE)
+ return "device";
+ } else if (role.getTag() == PortRole::mode) {
+ if (role.get<PortRole::mode>() == PortMode::UFP)
+ return "sink";
+ if (role.get<PortRole::mode>() == PortMode::DFP)
+ return "source";
+ }
+ return "none";
+}
+
+void extractRole(string *roleName) {
+ std::size_t first, last;
+
+ first = roleName->find("[");
+ last = roleName->find("]");
+
+ if (first != string::npos && last != string::npos) {
+ *roleName = roleName->substr(first + 1, last - first - 1);
+ }
+}
+
+void switchToDrp(const string &portName) {
+ string filename = appendRoleNodeHelper(string(portName.c_str()), PortRole::mode);
+ FILE *fp;
+
+ if (filename != "") {
+ fp = fopen(filename.c_str(), "w");
+ if (fp != NULL) {
+ int ret = fputs("dual", fp);
+ fclose(fp);
+ if (ret == EOF)
+ ALOGE("Fatal: Error while switching back to drp");
+ } else {
+ ALOGE("Fatal: Cannot open file to switch back to drp");
+ }
+ } else {
+ ALOGE("Fatal: invalid node type");
+ }
+}
+
+bool switchMode(const string &portName, const PortRole &in_role, struct Usb *usb) {
+ string filename = appendRoleNodeHelper(string(portName.c_str()), in_role.getTag());
+ string written;
+ FILE *fp;
+ bool roleSwitch = false;
+
+ if (filename == "") {
+ ALOGE("Fatal: invalid node type");
+ return false;
+ }
+
+ fp = fopen(filename.c_str(), "w");
+ if (fp != NULL) {
+ // Hold the lock here to prevent loosing connected signals
+ // as once the file is written the partner added signal
+ // can arrive anytime.
+ pthread_mutex_lock(&usb->mPartnerLock);
+ usb->mPartnerUp = false;
+ int ret = fputs(convertRoletoString(in_role).c_str(), fp);
+ fclose(fp);
+
+ if (ret != EOF) {
+ struct timespec to;
+ struct timespec now;
+
+ wait_again:
+ clock_gettime(CLOCK_MONOTONIC, &now);
+ to.tv_sec = now.tv_sec + PORT_TYPE_TIMEOUT;
+ to.tv_nsec = now.tv_nsec;
+
+ int err = pthread_cond_timedwait(&usb->mPartnerCV, &usb->mPartnerLock, &to);
+ // There are no uevent signals which implies role swap timed out.
+ if (err == ETIMEDOUT) {
+ ALOGI("uevents wait timedout");
+ // Validity check.
+ } else if (!usb->mPartnerUp) {
+ goto wait_again;
+ // Role switch succeeded since usb->mPartnerUp is true.
+ } else {
+ roleSwitch = true;
+ }
+ } else {
+ ALOGI("Role switch failed while wrting to file");
+ }
+ pthread_mutex_unlock(&usb->mPartnerLock);
+ }
+
+ if (!roleSwitch)
+ switchToDrp(string(portName.c_str()));
+
+ return roleSwitch;
+}
+
+Usb::Usb()
+ : mLock(PTHREAD_MUTEX_INITIALIZER),
+ mRoleSwitchLock(PTHREAD_MUTEX_INITIALIZER),
+ mPartnerLock(PTHREAD_MUTEX_INITIALIZER),
+ mPartnerUp(false)
+{
+ pthread_condattr_t attr;
+ if (pthread_condattr_init(&attr)) {
+ ALOGE("pthread_condattr_init failed: %s", strerror(errno));
+ abort();
+ }
+ if (pthread_condattr_setclock(&attr, CLOCK_MONOTONIC)) {
+ ALOGE("pthread_condattr_setclock failed: %s", strerror(errno));
+ abort();
+ }
+ if (pthread_cond_init(&mPartnerCV, &attr)) {
+ ALOGE("pthread_cond_init failed: %s", strerror(errno));
+ abort();
+ }
+ if (pthread_condattr_destroy(&attr)) {
+ ALOGE("pthread_condattr_destroy failed: %s", strerror(errno));
+ abort();
+ }
+}
+
+ScopedAStatus Usb::switchRole(const string& in_portName,
+ const PortRole& in_role, int64_t in_transactionId) {
+ string filename = appendRoleNodeHelper(string(in_portName.c_str()), in_role.getTag());
+ string written;
+ FILE *fp;
+ bool roleSwitch = false;
+
+ if (filename == "") {
+ ALOGE("Fatal: invalid node type");
+ return ScopedAStatus::ok();
+ }
+
+ pthread_mutex_lock(&mRoleSwitchLock);
+
+ ALOGI("filename write: %s role:%s", filename.c_str(), convertRoletoString(in_role).c_str());
+
+ if (in_role.getTag() == PortRole::mode) {
+ roleSwitch = switchMode(in_portName, in_role, this);
+ } else {
+ fp = fopen(filename.c_str(), "w");
+ if (fp != NULL) {
+ int ret = fputs(convertRoletoString(in_role).c_str(), fp);
+ fclose(fp);
+ if ((ret != EOF) && ReadFileToString(filename, &written)) {
+ written = Trim(written);
+ extractRole(&written);
+ ALOGI("written: %s", written.c_str());
+ if (written == convertRoletoString(in_role)) {
+ roleSwitch = true;
+ } else {
+ ALOGE("Role switch failed");
+ }
+ } else {
+ ALOGE("failed to update the new role");
+ }
+ } else {
+ ALOGE("fopen failed");
+ }
+ }
+
+ pthread_mutex_lock(&mLock);
+ if (mCallback != NULL) {
+ ScopedAStatus ret = mCallback->notifyRoleSwitchStatus(
+ in_portName, in_role, roleSwitch ? Status::SUCCESS : Status::ERROR, in_transactionId);
+ if (!ret.isOk())
+ ALOGE("RoleSwitchStatus error %s", ret.getDescription().c_str());
+ } else {
+ ALOGE("Not notifying the userspace. Callback is not set");
+ }
+ pthread_mutex_unlock(&mLock);
+ pthread_mutex_unlock(&mRoleSwitchLock);
+
+ return ScopedAStatus::ok();
+}
+
+Status getAccessoryConnected(const string &portName, string *accessory) {
+ string filename = kTypecPath + portName + "-partner/accessory_mode";
+
+ if (!ReadFileToString(filename, accessory)) {
+ ALOGE("getAccessoryConnected: Failed to open filesystem node: %s", filename.c_str());
+ return Status::ERROR;
+ }
+ *accessory = Trim(*accessory);
+
+ return Status::SUCCESS;
+}
+
+Status getCurrentRoleHelper(const string &portName, bool connected, PortRole *currentRole) {
+ string filename;
+ string roleName;
+ string accessory;
+
+ // Mode
+
+ if (currentRole->getTag() == PortRole::powerRole) {
+ filename = kTypecPath + portName + kPowerRoleNode;
+ currentRole->set<PortRole::powerRole>(PortPowerRole::NONE);
+ } else if (currentRole->getTag() == PortRole::dataRole) {
+ filename = kTypecPath + portName + kDataRoleNode;
+ currentRole->set<PortRole::dataRole>(PortDataRole::NONE);
+ } else if (currentRole->getTag() == PortRole::mode) {
+ filename = kTypecPath + portName + kDataRoleNode;
+ currentRole->set<PortRole::mode>(PortMode::NONE);
+ } else {
+ return Status::ERROR;
+ }
+
+ if (!connected)
+ return Status::SUCCESS;
+
+ if (currentRole->getTag() == PortRole::mode) {
+ if (getAccessoryConnected(portName, &accessory) != Status::SUCCESS) {
+ return Status::ERROR;
+ }
+ if (accessory == "analog_audio") {
+ currentRole->set<PortRole::mode>(PortMode::AUDIO_ACCESSORY);
+ return Status::SUCCESS;
+ } else if (accessory == "debug") {
+ currentRole->set<PortRole::mode>(PortMode::DEBUG_ACCESSORY);
+ return Status::SUCCESS;
+ }
+ }
+
+ if (!ReadFileToString(filename, &roleName)) {
+ ALOGE("getCurrentRole: Failed to open filesystem node: %s", filename.c_str());
+ return Status::ERROR;
+ }
+
+ roleName = Trim(roleName);
+ extractRole(&roleName);
+
+ if (roleName == "source") {
+ currentRole->set<PortRole::powerRole>(PortPowerRole::SOURCE);
+ } else if (roleName == "sink") {
+ currentRole->set<PortRole::powerRole>(PortPowerRole::SINK);
+ } else if (roleName == "host") {
+ if (currentRole->getTag() == PortRole::dataRole)
+ currentRole->set<PortRole::dataRole>(PortDataRole::HOST);
+ else
+ currentRole->set<PortRole::mode>(PortMode::DFP);
+ } else if (roleName == "device") {
+ if (currentRole->getTag() == PortRole::dataRole)
+ currentRole->set<PortRole::dataRole>(PortDataRole::DEVICE);
+ else
+ currentRole->set<PortRole::mode>(PortMode::UFP);
+ } else if (roleName != "none") {
+ /* case for none has already been addressed.
+ * so we check if the role isn't none.
+ */
+ return Status::UNRECOGNIZED_ROLE;
+ }
+
+ return Status::SUCCESS;
+}
+
+Status getTypeCPortNamesHelper(std::unordered_map<string, bool> *names) {
+ DIR *dp;
+
+ dp = opendir(kTypecPath);
+ if (dp != NULL) {
+ struct dirent *ep;
+
+ while ((ep = readdir(dp))) {
+ if (ep->d_type == DT_LNK) {
+ if (string::npos == string(ep->d_name).find("-partner")) {
+ std::unordered_map<string, bool>::const_iterator portName =
+ names->find(ep->d_name);
+ if (portName == names->end()) {
+ names->insert({ep->d_name, false});
+ }
+ } else {
+ (*names)[std::strtok(ep->d_name, "-")] = true;
+ }
+ }
+ }
+ closedir(dp);
+ return Status::SUCCESS;
+ }
+
+ ALOGE("Failed to open /sys/class/typec");
+ return Status::ERROR;
+}
+
+bool canSwitchRoleHelper(const string &portName) {
+ string filename = kTypecPath + portName + "-partner/supports_usb_power_delivery";
+ string supportsPD;
+
+ if (ReadFileToString(filename, &supportsPD)) {
+ supportsPD = Trim(supportsPD);
+ if (supportsPD == "yes") {
+ return true;
+ }
+ }
+
+ return false;
+}
+
+Status getPortStatusHelper(std::vector<PortStatus> *currentPortStatus) {
+ std::unordered_map<string, bool> names;
+ Status result = getTypeCPortNamesHelper(&names);
+ int i = -1;
+
+ if (result == Status::SUCCESS) {
+ currentPortStatus->resize(names.size());
+ for (std::pair<string, bool> port : names) {
+ i++;
+ ALOGI("%s", port.first.c_str());
+ (*currentPortStatus)[i].portName = port.first;
+
+ PortRole currentRole;
+ currentRole.set<PortRole::powerRole>(PortPowerRole::NONE);
+ if (getCurrentRoleHelper(port.first, port.second, ¤tRole) == Status::SUCCESS){
+ (*currentPortStatus)[i].currentPowerRole = currentRole.get<PortRole::powerRole>();
+ } else {
+ ALOGE("Error while retrieving portNames");
+ goto done;
+ }
+
+ currentRole.set<PortRole::dataRole>(PortDataRole::NONE);
+ if (getCurrentRoleHelper(port.first, port.second, ¤tRole) == Status::SUCCESS) {
+ (*currentPortStatus)[i].currentDataRole = currentRole.get<PortRole::dataRole>();
+ } else {
+ ALOGE("Error while retrieving current port role");
+ goto done;
+ }
+
+ currentRole.set<PortRole::mode>(PortMode::NONE);
+ if (getCurrentRoleHelper(port.first, port.second, ¤tRole) == Status::SUCCESS) {
+ (*currentPortStatus)[i].currentMode = currentRole.get<PortRole::mode>();
+ } else {
+ ALOGE("Error while retrieving current data role");
+ goto done;
+ }
+
+ (*currentPortStatus)[i].canChangeMode = true;
+ (*currentPortStatus)[i].canChangeDataRole =
+ port.second ? canSwitchRoleHelper(port.first) : false;
+ (*currentPortStatus)[i].canChangePowerRole =
+ port.second ? canSwitchRoleHelper(port.first) : false;
+
+ (*currentPortStatus)[i].supportedModes.push_back(PortMode::DRP);
+ (*currentPortStatus)[i].usbDataEnabled = true;
+
+ ALOGI("%d:%s connected:%d canChangeMode:%d canChagedata:%d canChangePower:%d "
+ "usbDataEnabled:%d",
+ i, port.first.c_str(), port.second,
+ (*currentPortStatus)[i].canChangeMode,
+ (*currentPortStatus)[i].canChangeDataRole,
+ (*currentPortStatus)[i].canChangePowerRole, 0);
+ }
+
+ return Status::SUCCESS;
+ }
+done:
+ return Status::ERROR;
+}
+
+void queryVersionHelper(android::hardware::usb::Usb *usb,
+ std::vector<PortStatus> *currentPortStatus) {
+ Status status;
+ pthread_mutex_lock(&usb->mLock);
+ status = getPortStatusHelper(currentPortStatus);
+ queryMoistureDetectionStatus(currentPortStatus);
+ if (usb->mCallback != NULL) {
+ ScopedAStatus ret = usb->mCallback->notifyPortStatusChange(*currentPortStatus,
+ status);
+ if (!ret.isOk())
+ ALOGE("queryPortStatus error %s", ret.getDescription().c_str());
+ } else {
+ ALOGI("Notifying userspace skipped. Callback is NULL");
+ }
+ pthread_mutex_unlock(&usb->mLock);
+}
+
+ScopedAStatus Usb::queryPortStatus(int64_t in_transactionId) {
+ std::vector<PortStatus> currentPortStatus;
+
+ queryVersionHelper(this, ¤tPortStatus);
+ pthread_mutex_lock(&mLock);
+ if (mCallback != NULL) {
+ ScopedAStatus ret = mCallback->notifyQueryPortStatus(
+ "all", Status::SUCCESS, in_transactionId);
+ if (!ret.isOk())
+ ALOGE("notifyQueryPortStatus error %s", ret.getDescription().c_str());
+ } else {
+ ALOGE("Not notifying the userspace. Callback is not set");
+ }
+ pthread_mutex_unlock(&mLock);
+
+ return ScopedAStatus::ok();
+}
+
+ScopedAStatus Usb::enableContaminantPresenceDetection(const string& in_portName,
+ bool /*in_enable*/, int64_t in_transactionId) {
+ std::vector<PortStatus> currentPortStatus;
+
+ pthread_mutex_lock(&mLock);
+ if (mCallback != NULL) {
+ ScopedAStatus ret = mCallback->notifyContaminantEnabledStatus(
+ in_portName, false, Status::ERROR, in_transactionId);
+ if (!ret.isOk())
+ ALOGE("enableContaminantPresenceDetection error %s", ret.getDescription().c_str());
+ } else {
+ ALOGE("Not notifying the userspace. Callback is not set");
+ }
+ pthread_mutex_unlock(&mLock);
+
+ queryVersionHelper(this, ¤tPortStatus);
+ return ScopedAStatus::ok();
+}
+
+
+struct data {
+ int uevent_fd;
+ ::aidl::android::hardware::usb::Usb *usb;
+};
+
+static void uevent_event(uint32_t /*epevents*/, struct data *payload) {
+ char msg[UEVENT_MSG_LEN + 2];
+ char *cp;
+ int n;
+
+ n = uevent_kernel_multicast_recv(payload->uevent_fd, msg, UEVENT_MSG_LEN);
+ if (n <= 0)
+ return;
+ if (n >= UEVENT_MSG_LEN) /* overflow -- discard */
+ return;
+
+ msg[n] = '\0';
+ msg[n + 1] = '\0';
+ cp = msg;
+
+ while (*cp) {
+ if (std::regex_match(cp, std::regex("(add)(.*)(-partner)"))) {
+ ALOGI("partner added");
+ pthread_mutex_lock(&payload->usb->mPartnerLock);
+ payload->usb->mPartnerUp = true;
+ pthread_cond_signal(&payload->usb->mPartnerCV);
+ pthread_mutex_unlock(&payload->usb->mPartnerLock);
+ } else if (!strncmp(cp, "DEVTYPE=typec_", strlen("DEVTYPE=typec_"))) {
+ std::vector<PortStatus> currentPortStatus;
+ queryVersionHelper(payload->usb, ¤tPortStatus);
+
+ // Role switch is not in progress and port is in disconnected state
+ if (!pthread_mutex_trylock(&payload->usb->mRoleSwitchLock)) {
+ for (unsigned long i = 0; i < currentPortStatus.size(); i++) {
+ DIR *dp =
+ opendir(string(kTypecPath +
+ string(currentPortStatus[i].portName.c_str()) +
+ "-partner").c_str());
+ if (dp == NULL) {
+ switchToDrp(currentPortStatus[i].portName);
+ } else {
+ closedir(dp);
+ }
+ }
+ pthread_mutex_unlock(&payload->usb->mRoleSwitchLock);
+ }
+ break;
+ } /* advance to after the next \0 */
+ while (*cp++) {
+ }
+ }
+}
+
+void *work(void *param) {
+ int epoll_fd, uevent_fd;
+ struct epoll_event ev;
+ int nevents = 0;
+ struct data payload;
+
+ uevent_fd = uevent_open_socket(UEVENT_MAX_EVENTS * UEVENT_MSG_LEN, true);
+
+ if (uevent_fd < 0) {
+ ALOGE("uevent_init: uevent_open_socket failed\n");
+ return NULL;
+ }
+
+ payload.uevent_fd = uevent_fd;
+ payload.usb = (::aidl::android::hardware::usb::Usb *)param;
+
+ fcntl(uevent_fd, F_SETFL, O_NONBLOCK);
+
+ ev.events = EPOLLIN;
+ ev.data.ptr = (void *)uevent_event;
+
+ epoll_fd = epoll_create(UEVENT_MAX_EVENTS);
+ if (epoll_fd == -1) {
+ ALOGE("epoll_create failed; errno=%d", errno);
+ goto error;
+ }
+
+ if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, uevent_fd, &ev) == -1) {
+ ALOGE("epoll_ctl failed; errno=%d", errno);
+ goto error;
+ }
+
+ while (!destroyThread) {
+ struct epoll_event events[UEVENT_MAX_EVENTS];
+
+ nevents = epoll_wait(epoll_fd, events, UEVENT_MAX_EVENTS, -1);
+ if (nevents == -1) {
+ if (errno == EINTR)
+ continue;
+ ALOGE("usb epoll_wait failed; errno=%d", errno);
+ break;
+ }
+
+ for (int n = 0; n < nevents; ++n) {
+ if (events[n].data.ptr)
+ (*(void (*)(int, struct data *payload))events[n].data.ptr)(events[n].events,
+ &payload);
+ }
+ }
+
+ ALOGI("exiting worker thread");
+error:
+ close(uevent_fd);
+
+ if (epoll_fd >= 0)
+ close(epoll_fd);
+
+ return NULL;
+}
+
+void sighandler(int sig) {
+ if (sig == SIGUSR1) {
+ destroyThread = true;
+ ALOGI("destroy set");
+ return;
+ }
+ signal(SIGUSR1, sighandler);
+}
+
+ScopedAStatus Usb::setCallback(
+ const shared_ptr<IUsbCallback>& in_callback) {
+
+ pthread_mutex_lock(&mLock);
+ if ((mCallback == NULL && in_callback == NULL) ||
+ (mCallback != NULL && in_callback != NULL)) {
+ mCallback = in_callback;
+ pthread_mutex_unlock(&mLock);
+ return ScopedAStatus::ok();
+ }
+
+ mCallback = in_callback;
+ ALOGI("registering callback");
+
+ if (mCallback == NULL) {
+ if (!pthread_kill(mPoll, SIGUSR1)) {
+ pthread_join(mPoll, NULL);
+ ALOGI("pthread destroyed");
+ }
+ pthread_mutex_unlock(&mLock);
+ return ScopedAStatus::ok();
+ }
+
+ destroyThread = false;
+ signal(SIGUSR1, sighandler);
+
+ /*
+ * Create a background thread if the old callback value is NULL
+ * and being updated with a new value.
+ */
+ if (pthread_create(&mPoll, NULL, work, this)) {
+ ALOGE("pthread creation failed %d", errno);
+ mCallback = NULL;
+ }
+
+ pthread_mutex_unlock(&mLock);
+ return ScopedAStatus::ok();
+}
+
+} // namespace usb
+} // namespace hardware
+} // namespace android
+} // aidl