AIDL CAN HAL
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Bug: 170405615
Test: atest CanControllerAidlTest
Test: manually test slcan and socketcan hardware
Change-Id: I06bbb1379f4385e89757722c0276009b54cc7255
diff --git a/automotive/can/aidl/default/CanController.cpp b/automotive/can/aidl/default/CanController.cpp
new file mode 100644
index 0000000..e4b5306
--- /dev/null
+++ b/automotive/can/aidl/default/CanController.cpp
@@ -0,0 +1,333 @@
+/*
+ * Copyright 2022, 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 "CanController.h"
+
+#include "CanBusNative.h"
+#include "CanBusSlcan.h"
+#include "CanBusVirtual.h"
+
+#include <android-base/format.h>
+#include <android-base/logging.h>
+
+#include <automotive/filesystem>
+#include <fstream>
+#include <regex>
+
+namespace aidl::android::hardware::automotive::can {
+
+namespace fs = ::android::hardware::automotive::filesystem;
+
+namespace fsErrors {
+static const std::error_code ok;
+static const std::error_code eperm(EPERM, std::generic_category());
+static const std::error_code enoent(ENOENT, std::generic_category());
+static const std::error_code eacces(EACCES, std::generic_category());
+} // namespace fsErrors
+
+/* In the /sys/devices tree, there are files called "serial", which contain the serial numbers
+ * for various devices. The exact location inside of this directory is dependent upon the
+ * hardware we are running on, so we have to start from /sys/devices and work our way down. */
+static const fs::path kDevPath("/sys/devices/");
+static const std::regex kTtyRe("^tty[A-Z]+[0-9]+$");
+static constexpr auto kOpts = ~(fs::directory_options::follow_directory_symlink |
+ fs::directory_options::skip_permission_denied);
+
+constexpr auto ok = &ndk::ScopedAStatus::ok;
+
+/**
+ * A helper object to associate the interface name and type of a USB to CAN adapter.
+ */
+struct UsbCanIface {
+ InterfaceType iftype;
+ std::string ifaceName;
+};
+
+static bool isValidName(const std::string& name) {
+ static const std::regex nameRE("^[a-zA-Z0-9_]{1,32}$");
+ return std::regex_match(name, nameRE);
+}
+
+/**
+ * Given a path, get the last element from it.
+ *
+ * \param itrPath - the path we want the last element of
+ * \return - the last element in the path (in string form).
+ */
+static std::string getLeaf(const fs::path& itrPath) {
+ /* end() returns an iterator one past the leaf of the path, so we've overshot
+ decrement (--) to go back one to the leaf
+ dereference and now we have our leaf. */
+ return *(--(itrPath.end()));
+}
+
+static ndk::ScopedAStatus resultToStatus(Result res, const std::string& msg = "") {
+ if (msg.empty()) {
+ return ndk::ScopedAStatus(AStatus_fromServiceSpecificError(static_cast<int>(res)));
+ }
+ return ndk::ScopedAStatus(
+ AStatus_fromServiceSpecificErrorWithMessage(static_cast<int>(res), msg.c_str()));
+}
+
+/**
+ * Given a UsbCanIface object, get the ifaceName given the serialPath.
+ *
+ * \param serialPath - Absolute path to a "serial" file for a given device in /sys.
+ * \return A populated UsbCanIface. On failure, nullopt is returned.
+ */
+static std::optional<UsbCanIface> getIfaceName(const fs::path& serialPath) {
+ std::error_code fsStatus;
+ // Since the path is to a file called "serial", we need to search its parent directory.
+ fs::recursive_directory_iterator fsItr(serialPath.parent_path(), kOpts, fsStatus);
+ if (fsStatus != fsErrors::ok) {
+ LOG(ERROR) << "Failed to open " << serialPath.parent_path();
+ return std::nullopt;
+ }
+
+ for (; fsStatus == fsErrors::ok && fsItr != fs::recursive_directory_iterator();
+ fsItr.increment(fsStatus)) {
+ /* We want either a directory called "net" or a directory that looks like tty<something>, so
+ * skip files. */
+ bool isDir = fsItr->is_directory(fsStatus);
+ if (fsStatus != fsErrors::ok || !isDir) continue;
+
+ std::string currentDir = getLeaf(fsItr->path());
+ if (currentDir == "net") {
+ /* This device is a SocketCAN device. The iface name is the only directory under
+ * net/. Multiple directories under net/ is an error.*/
+ fs::directory_iterator netItr(fsItr->path(), kOpts, fsStatus);
+ if (fsStatus != fsErrors::ok) {
+ LOG(ERROR) << "Failed to open " << fsItr->path() << " to get net name!";
+ return std::nullopt;
+ }
+
+ // The leaf of our path should be the interface name.
+ std::string netName = getLeaf(netItr->path());
+
+ // Check if there is more than one item in net/
+ netItr.increment(fsStatus);
+ if (fsStatus != fsErrors::ok) {
+ // It's possible we have a valid net name, but this is most likely an error.
+ LOG(ERROR) << "Failed to verify " << fsItr->path() << " has valid net name!";
+ return std::nullopt;
+ }
+ if (netItr != fs::directory_iterator()) {
+ // There should never be more than one name under net/
+ LOG(ERROR) << "Found more than one net name in " << fsItr->path() << "!";
+ return std::nullopt;
+ }
+ return {{InterfaceType::NATIVE, netName}};
+ } else if (std::regex_match(currentDir, kTtyRe)) {
+ // This device is a USB serial device, and currentDir is the tty name.
+ return {{InterfaceType::SLCAN, "/dev/" + currentDir}};
+ }
+ }
+
+ // check if the loop above exited due to a c++fs error.
+ if (fsStatus != fsErrors::ok) {
+ LOG(ERROR) << "Failed search filesystem: " << fsStatus;
+ }
+ return std::nullopt;
+}
+
+/**
+ * A helper function to read the serial number from a "serial" file in /sys/devices/
+ *
+ * \param serialnoPath - path to the file to read.
+ * \return the serial number, or nullopt on failure.
+ */
+static std::optional<std::string> readSerialNo(const std::string& serialnoPath) {
+ std::ifstream serialnoStream(serialnoPath);
+ std::string serialno;
+ if (!serialnoStream.good()) {
+ LOG(ERROR) << "Failed to read serial number from " << serialnoPath;
+ return std::nullopt;
+ }
+ std::getline(serialnoStream, serialno);
+ return serialno;
+}
+
+/**
+ * Searches for USB devices found in /sys/devices/, and attempts to find a device matching the
+ * provided list of serial numbers.
+ *
+ * \param configSerialnos - a list of serial number (suffixes) from the HAL config.
+ * \param iftype - the type of the interface to be located.
+ * \return a matching USB device. On failure, std::nullopt is returned.
+ */
+static std::optional<UsbCanIface> findUsbDevice(const std::vector<std::string>& configSerialnos) {
+ std::error_code fsStatus;
+ fs::recursive_directory_iterator fsItr(kDevPath, kOpts, fsStatus);
+ if (fsStatus != fsErrors::ok) {
+ LOG(ERROR) << "Failed to open " << kDevPath;
+ return std::nullopt;
+ }
+
+ for (; fsStatus == fsErrors::ok && fsItr != fs::recursive_directory_iterator();
+ fsItr.increment(fsStatus)) {
+ // We want to find a file called "serial", which is in a directory somewhere. Skip files.
+ bool isDir = fsItr->is_directory(fsStatus);
+ if (fsStatus != fsErrors::ok) {
+ LOG(ERROR) << "Failed check if " << fsStatus;
+ return std::nullopt;
+ }
+ if (!isDir) continue;
+
+ auto serialnoPath = fsItr->path() / "serial";
+ bool isReg = fs::is_regular_file(serialnoPath, fsStatus);
+
+ /* Make sure we have permissions to this directory, ignore enoent, since the file
+ * "serial" may not exist, which is ok. */
+ if (fsStatus == fsErrors::eperm || fsStatus == fsErrors::eacces) {
+ /* This means we don't have access to this directory. If we recurse into it, this
+ * will cause the iterator to loose its state and we'll crash. */
+ fsItr.disable_recursion_pending();
+ continue;
+ }
+ if (fsStatus == fsErrors::enoent) continue;
+ if (fsStatus != fsErrors::ok) {
+ LOG(WARNING) << "An unexpected error occurred while checking for serialno: "
+ << fsStatus;
+ continue;
+ }
+ if (!isReg) continue;
+
+ // we found a serial number
+ auto serialno = readSerialNo(serialnoPath);
+ if (!serialno.has_value()) continue;
+
+ // see if the serial number exists in the config
+ for (auto&& cfgSn : configSerialnos) {
+ if (serialno->ends_with(std::string(cfgSn))) {
+ auto ifaceInfo = getIfaceName(serialnoPath);
+ if (!ifaceInfo.has_value()) break;
+ return ifaceInfo;
+ }
+ }
+ }
+ if (fsStatus != fsErrors::ok) {
+ LOG(ERROR) << "Error searching filesystem: " << fsStatus;
+ return std::nullopt;
+ }
+ return std::nullopt;
+}
+
+ndk::ScopedAStatus CanController::getSupportedInterfaceTypes(
+ std::vector<InterfaceType>* supportedTypes) {
+ *supportedTypes = {InterfaceType::VIRTUAL, InterfaceType::NATIVE, InterfaceType::SLCAN};
+ return ok();
+}
+
+ndk::ScopedAStatus CanController::getInterfaceName(const std::string& busName,
+ std::string* ifaceName) {
+ *ifaceName = {};
+ if (mBusesByName.find(busName) == mBusesByName.end()) {
+ return resultToStatus(Result::BAD_BUS_NAME, fmt::format("{} doesn't exist", busName));
+ }
+ *ifaceName = std::string(mBusesByName[busName]->getIfaceName());
+ return ok();
+}
+
+ndk::ScopedAStatus CanController::upBus(const BusConfig& config, std::string* ifaceName) {
+ if (!isValidName(config.name)) {
+ LOG(ERROR) << "Bus name " << config.name << " is invalid";
+ return resultToStatus(Result::BAD_BUS_NAME,
+ fmt::format("{} is not a valid bus name", config.name));
+ } else if (mBusesByName.find(config.name) != mBusesByName.end()) {
+ LOG(ERROR) << "A bus named " << config.name << " already exists!";
+ return resultToStatus(Result::INVALID_STATE,
+ fmt::format("A bus named {} already exists", config.name));
+ }
+
+ if (config.interfaceId.getTag() == BusConfig::InterfaceId::Tag::virtualif) {
+ auto& virtualif = config.interfaceId.get<BusConfig::InterfaceId::Tag::virtualif>();
+ mBusesByName[config.name] = std::make_unique<CanBusVirtual>(virtualif.ifname);
+ }
+
+ else if (config.interfaceId.getTag() == BusConfig::InterfaceId::Tag::nativeif) {
+ auto& nativeif = config.interfaceId.get<BusConfig::InterfaceId::Tag::nativeif>();
+ std::string ifaceName;
+ if (nativeif.interfaceId.getTag() == NativeInterface::InterfaceId::Tag::serialno) {
+ // Configure by serial number.
+ auto selectedDevice = findUsbDevice(
+ nativeif.interfaceId.get<NativeInterface::InterfaceId::Tag::serialno>());
+ // verify the returned device is the correct one
+ if (!selectedDevice.has_value() || selectedDevice->iftype != InterfaceType::NATIVE) {
+ return resultToStatus(
+ Result::BAD_INTERFACE_ID,
+ "Couldn't find a native socketcan device with the given serial number(s)");
+ }
+ ifaceName = selectedDevice->ifaceName;
+ } else {
+ // configure by iface name.
+ ifaceName = nativeif.interfaceId.get<NativeInterface::InterfaceId::Tag::ifname>();
+ }
+ mBusesByName[config.name] = std::make_unique<CanBusNative>(ifaceName, config.bitrate);
+ }
+
+ else if (config.interfaceId.getTag() == BusConfig::InterfaceId::Tag::slcan) {
+ auto& slcanif = config.interfaceId.get<BusConfig::InterfaceId::Tag::slcan>();
+ std::string ttyName;
+ if (slcanif.interfaceId.getTag() == SlcanInterface::InterfaceId::Tag::serialno) {
+ // Configure by serial number.
+ auto selectedDevice = findUsbDevice(
+ slcanif.interfaceId.get<SlcanInterface::InterfaceId::Tag::serialno>());
+ if (!selectedDevice.has_value() || selectedDevice->iftype != InterfaceType::SLCAN) {
+ return resultToStatus(
+ Result::BAD_INTERFACE_ID,
+ "Couldn't find a slcan device with the given serial number(s)");
+ }
+ ttyName = selectedDevice->ifaceName;
+ } else {
+ // Configure by tty name.
+ ttyName = slcanif.interfaceId.get<SlcanInterface::InterfaceId::Tag::ttyname>();
+ }
+ mBusesByName[config.name] = std::make_unique<CanBusSlcan>(ttyName, config.bitrate);
+ }
+
+ else if (config.interfaceId.getTag() == BusConfig::InterfaceId::Tag::indexed) {
+ return resultToStatus(Result::NOT_SUPPORTED,
+ "Indexed devices are not supported in this implementation");
+ } else {
+ // this shouldn't happen.
+ return resultToStatus(Result::UNKNOWN_ERROR, "Unknown interface id type");
+ }
+
+ Result result = mBusesByName[config.name]->up();
+ if (result != Result::OK) {
+ // the bus failed to come up, don't leave a broken entry in the map.
+ mBusesByName.erase(config.name);
+ return resultToStatus(result, fmt::format("CanBus::up failed for {}", config.name));
+ }
+
+ *ifaceName = mBusesByName[config.name]->getIfaceName();
+ return ok();
+}
+
+ndk::ScopedAStatus CanController::downBus(const std::string& busName) {
+ if (mBusesByName.find(busName) == mBusesByName.end()) {
+ return resultToStatus(
+ Result::UNKNOWN_ERROR,
+ fmt::format("Couldn't bring down {}, because it doesn't exist", busName));
+ }
+ Result result = mBusesByName[busName]->down();
+ if (result != Result::OK) {
+ return resultToStatus(result, fmt::format("Couldn't bring down {}!", busName));
+ }
+ mBusesByName.erase(busName);
+ return ok();
+}
+} // namespace aidl::android::hardware::automotive::can