1 files changed, 223 insertions, 0 deletions
diff --git a/fs_mgr/libsnapshot/snapuserd_client.cpp b/fs_mgr/libsnapshot/snapuserd_client.cpp
new file mode 100644
index 000000000..41ab34409
--- /dev/null
+++ b/fs_mgr/libsnapshot/snapuserd_client.cpp
@@ -0,0 +1,223 @@
+/*
+ * Copyright (C) 2020 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 <arpa/inet.h>
+#include <cutils/sockets.h>
+#include <errno.h>
+#include <netdb.h>
+#include <netinet/in.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <chrono>
+#include <sstream>
+
+#include <android-base/logging.h>
+#include <android-base/parseint.h>
+#include <android-base/properties.h>
+#include <android-base/strings.h>
+#include <libsnapshot/snapuserd_client.h>
+
+namespace android {
+namespace snapshot {
+
+using namespace std::chrono_literals;
+using android::base::unique_fd;
+
+bool EnsureSnapuserdStarted() {
+    if (android::base::GetProperty("init.svc.snapuserd", "") == "running") {
+        return true;
+    }
+
+    android::base::SetProperty("ctl.start", "snapuserd");
+    if (!android::base::WaitForProperty("init.svc.snapuserd", "running", 10s)) {
+        LOG(ERROR) << "Timed out waiting for snapuserd to start.";
+        return false;
+    }
+    return true;
+}
+
+SnapuserdClient::SnapuserdClient(android::base::unique_fd&& sockfd) : sockfd_(std::move(sockfd)) {}
+
+static inline bool IsRetryErrno() {
+    return errno == ECONNREFUSED || errno == EINTR || errno == ENOENT;
+}
+
+std::unique_ptr<SnapuserdClient> SnapuserdClient::Connect(const std::string& socket_name,
+                                                          std::chrono::milliseconds timeout_ms) {
+    unique_fd fd;
+    auto start = std::chrono::steady_clock::now();
+    while (true) {
+        fd.reset(socket_local_client(socket_name.c_str(), ANDROID_SOCKET_NAMESPACE_RESERVED,
+                                     SOCK_STREAM));
+        if (fd >= 0) break;
+        if (fd < 0 && !IsRetryErrno()) {
+            PLOG(ERROR) << "connect failed: " << socket_name;
+            return nullptr;
+        }
+
+        auto now = std::chrono::steady_clock::now();
+        auto elapsed = std::chrono::duration_cast<std::chrono::milliseconds>(now - start);
+        if (elapsed >= timeout_ms) {
+            LOG(ERROR) << "Timed out connecting to snapuserd socket: " << socket_name;
+            return nullptr;
+        }
+
+        std::this_thread::sleep_for(100ms);
+    }
+
+    auto client = std::make_unique<SnapuserdClient>(std::move(fd));
+    if (!client->ValidateConnection()) {
+        return nullptr;
+    }
+    return client;
+}
+
+bool SnapuserdClient::ValidateConnection() {
+    if (!Sendmsg("query")) {
+        return false;
+    }
+
+    std::string str = Receivemsg();
+
+    // If the daemon is passive then fallback to secondary active daemon. Daemon
+    // is passive during transition phase.
+    if (str.find("passive") != std::string::npos) {
+        LOG(ERROR) << "Snapuserd is terminating";
+        return false;
+    }
+
+    if (str != "active") {
+        LOG(ERROR) << "Received failure querying daemon";
+        return false;
+    }
+    return true;
+}
+
+bool SnapuserdClient::Sendmsg(const std::string& msg) {
+    LOG(DEBUG) << "Sendmsg: msg " << msg << " sockfd: " << sockfd_;
+    ssize_t numBytesSent = TEMP_FAILURE_RETRY(send(sockfd_, msg.data(), msg.size(), MSG_NOSIGNAL));
+    if (numBytesSent < 0) {
+        PLOG(ERROR) << "Send failed";
+        return false;
+    }
+
+    if ((size_t)numBytesSent < msg.size()) {
+        LOG(ERROR) << "Partial data sent, expected " << msg.size() << " bytes, sent "
+                   << numBytesSent;
+        return false;
+    }
+    return true;
+}
+
+bool SnapuserdClient::WaitForDeviceDelete(const std::string& control_device) {
+    std::string msg = "delete," + control_device;
+    if (!Sendmsg(msg)) {
+        LOG(ERROR) << "Failed to send message " << msg << " to snapuserd";
+        return false;
+    }
+    std::string response = Receivemsg();
+    if (response != "success") {
+        LOG(ERROR) << "Failed waiting to delete device " << control_device;
+        return false;
+    }
+    return true;
+}
+
+std::string SnapuserdClient::Receivemsg() {
+    char msg[PACKET_SIZE];
+    ssize_t ret = TEMP_FAILURE_RETRY(recv(sockfd_, msg, sizeof(msg), 0));
+    if (ret < 0) {
+        PLOG(ERROR) << "Snapuserd:client: recv failed";
+        return {};
+    }
+    if (ret == 0) {
+        LOG(DEBUG) << "Snapuserd:client disconnected";
+        return {};
+    }
+    return std::string(msg, ret);
+}
+
+bool SnapuserdClient::StopSnapuserd() {
+    if (!Sendmsg("stop")) {
+        LOG(ERROR) << "Failed to send stop message to snapuserd daemon";
+        return false;
+    }
+
+    sockfd_ = {};
+    return true;
+}
+
+bool SnapuserdClient::AttachDmUser(const std::string& misc_name) {
+    std::string msg = "start," + misc_name;
+    if (!Sendmsg(msg)) {
+        LOG(ERROR) << "Failed to send message " << msg << " to snapuserd daemon";
+        return false;
+    }
+
+    std::string str = Receivemsg();
+    if (str != "success") {
+        LOG(ERROR) << "Failed to receive ack for " << msg << " from snapuserd daemon";
+        return false;
+    }
+
+    LOG(DEBUG) << "Snapuserd daemon initialized with " << msg;
+    return true;
+}
+
+uint64_t SnapuserdClient::InitDmUserCow(const std::string& misc_name, const std::string& cow_device,
+                                        const std::string& backing_device) {
+    std::vector<std::string> parts = {"init", misc_name, cow_device, backing_device};
+    std::string msg = android::base::Join(parts, ",");
+    if (!Sendmsg(msg)) {
+        LOG(ERROR) << "Failed to send message " << msg << " to snapuserd daemon";
+        return 0;
+    }
+
+    std::string str = Receivemsg();
+
+    std::vector<std::string> input = android::base::Split(str, ",");
+
+    if (input.empty() || input[0] != "success") {
+        LOG(ERROR) << "Failed to receive number of sectors for " << msg << " from snapuserd daemon";
+        return 0;
+    }
+
+    LOG(DEBUG) << "Snapuserd daemon COW device initialized: " << cow_device
+               << " Num-sectors: " << input[1];
+
+    uint64_t num_sectors = 0;
+    if (!android::base::ParseUint(input[1], &num_sectors)) {
+        LOG(ERROR) << "Failed to parse input string to sectors";
+        return 0;
+    }
+    return num_sectors;
+}
+
+bool SnapuserdClient::DetachSnapuserd() {
+    if (!Sendmsg("detach")) {
+        LOG(ERROR) << "Failed to detach snapuserd.";
+        return false;
+    }
+    return true;
+}
+
+}  // namespace snapshot
+}  // namespace android