diff --git a/adb/client/adb_client.cpp b/adb/client/adb_client.cpp
index 31c938c..a308732 100644
--- a/adb/client/adb_client.cpp
+++ b/adb/client/adb_client.cpp
@@ -417,17 +417,19 @@
 }
 
 const std::optional<FeatureSet>& adb_get_feature_set(std::string* error) {
-    static std::string cached_error [[clang::no_destroy]];
-    static const std::optional<FeatureSet> features
-            [[clang::no_destroy]] ([]() -> std::optional<FeatureSet> {
-                std::string result;
-                if (adb_query(format_host_command("features"), &result, &cached_error)) {
-                    return StringToFeatureSet(result);
-                }
-                return std::nullopt;
-            }());
-    if (!features && error) {
-        *error = cached_error;
+    static std::mutex feature_mutex [[clang::no_destroy]];
+    static std::optional<FeatureSet> features [[clang::no_destroy]] GUARDED_BY(feature_mutex);
+    std::lock_guard<std::mutex> lock(feature_mutex);
+    if (!features) {
+        std::string result;
+        std::string err;
+        if (adb_query(format_host_command("features"), &result, &err)) {
+            features = StringToFeatureSet(result);
+        } else {
+            if (error) {
+                *error = err;
+            }
+        }
     }
     return features;
 }
diff --git a/fastboot/Android.bp b/fastboot/Android.bp
index 6b49fc7..bdb786c 100644
--- a/fastboot/Android.bp
+++ b/fastboot/Android.bp
@@ -117,8 +117,10 @@
         "device/main.cpp",
         "device/usb.cpp",
         "device/usb_client.cpp",
+        "device/tcp_client.cpp",
         "device/utility.cpp",
         "device/variables.cpp",
+        "socket.cpp",
     ],
 
     shared_libs: [
@@ -143,6 +145,7 @@
     ],
 
     static_libs: [
+        "libgtest_prod",
         "libhealthhalutils",
         "libsnapshot_nobinder",
         "update_metadata-protos",
diff --git a/fastboot/device/fastboot_device.cpp b/fastboot/device/fastboot_device.cpp
index bb085c5..1b0859f 100644
--- a/fastboot/device/fastboot_device.cpp
+++ b/fastboot/device/fastboot_device.cpp
@@ -19,6 +19,7 @@
 #include <algorithm>
 
 #include <android-base/logging.h>
+#include <android-base/properties.h>
 #include <android-base/strings.h>
 #include <android/hardware/boot/1.0/IBootControl.h>
 #include <android/hardware/fastboot/1.0/IFastboot.h>
@@ -28,6 +29,7 @@
 
 #include "constants.h"
 #include "flashing.h"
+#include "tcp_client.h"
 #include "usb_client.h"
 
 using android::fs_mgr::EnsurePathUnmounted;
@@ -60,11 +62,16 @@
               {FB_CMD_GSI, GsiHandler},
               {FB_CMD_SNAPSHOT_UPDATE, SnapshotUpdateHandler},
       }),
-      transport_(std::make_unique<ClientUsbTransport>()),
       boot_control_hal_(IBootControl::getService()),
       health_hal_(get_health_service()),
       fastboot_hal_(IFastboot::getService()),
       active_slot_("") {
+    if (android::base::GetProperty("fastbootd.protocol", "usb") == "tcp") {
+        transport_ = std::make_unique<ClientTcpTransport>();
+    } else {
+        transport_ = std::make_unique<ClientUsbTransport>();
+    }
+
     if (boot_control_hal_) {
         boot1_1_ = android::hardware::boot::V1_1::IBootControl::castFrom(boot_control_hal_);
     }
diff --git a/fastboot/device/tcp_client.cpp b/fastboot/device/tcp_client.cpp
new file mode 100644
index 0000000..ec5e1e3
--- /dev/null
+++ b/fastboot/device/tcp_client.cpp
@@ -0,0 +1,176 @@
+/*
+ * 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 "tcp_client.h"
+#include "constants.h"
+
+#include <android-base/errors.h>
+#include <android-base/logging.h>
+#include <android-base/parseint.h>
+#include <android-base/properties.h>
+#include <android-base/stringprintf.h>
+#include <android-base/strings.h>
+
+static constexpr int kDefaultPort = 5554;
+static constexpr int kProtocolVersion = 1;
+static constexpr int kHandshakeTimeoutMs = 2000;
+static constexpr size_t kHandshakeLength = 4;
+
+// Extract the big-endian 8-byte message length into a 64-bit number.
+static uint64_t ExtractMessageLength(const void* buffer) {
+    uint64_t ret = 0;
+    for (int i = 0; i < 8; ++i) {
+        ret |= uint64_t{reinterpret_cast<const uint8_t*>(buffer)[i]} << (56 - i * 8);
+    }
+    return ret;
+}
+
+// Encode the 64-bit number into a big-endian 8-byte message length.
+static void EncodeMessageLength(uint64_t length, void* buffer) {
+    for (int i = 0; i < 8; ++i) {
+        reinterpret_cast<uint8_t*>(buffer)[i] = length >> (56 - i * 8);
+    }
+}
+
+ClientTcpTransport::ClientTcpTransport() {
+    service_ = Socket::NewServer(Socket::Protocol::kTcp, kDefaultPort);
+
+    // A workaround to notify recovery to continue its work.
+    android::base::SetProperty("sys.usb.ffs.ready", "1");
+}
+
+ssize_t ClientTcpTransport::Read(void* data, size_t len) {
+    if (len > SSIZE_MAX) {
+        return -1;
+    }
+
+    size_t total_read = 0;
+    do {
+        // Read a new message
+        while (message_bytes_left_ == 0) {
+            if (socket_ == nullptr) {
+                ListenFastbootSocket();
+            }
+
+            char buffer[8];
+            if (socket_->ReceiveAll(buffer, 8, 0) == 8) {
+                message_bytes_left_ = ExtractMessageLength(buffer);
+            } else {
+                // If connection is closed by host, Receive will return 0 immediately.
+                socket_.reset(nullptr);
+                // In DATA phase, return error.
+                if (downloading_) {
+                    return -1;
+                }
+            }
+        }
+
+        size_t read_length = len - total_read;
+        if (read_length > message_bytes_left_) {
+            read_length = message_bytes_left_;
+        }
+        ssize_t bytes_read =
+                socket_->ReceiveAll(reinterpret_cast<char*>(data) + total_read, read_length, 0);
+        if (bytes_read == -1) {
+            socket_.reset(nullptr);
+            return -1;
+        } else {
+            message_bytes_left_ -= bytes_read;
+            total_read += bytes_read;
+        }
+    // There are more than one DATA phases if the downloading buffer is too
+    // large, like a very big system image. All of data phases should be
+    // received until the whole buffer is filled in that case.
+    } while (downloading_ && total_read < len);
+
+    return total_read;
+}
+
+ssize_t ClientTcpTransport::Write(const void* data, size_t len) {
+    if (socket_ == nullptr || len > SSIZE_MAX) {
+        return -1;
+    }
+
+    // Use multi-buffer writes for better performance.
+    char header[8];
+    EncodeMessageLength(len, header);
+
+    if (!socket_->Send(std::vector<cutils_socket_buffer_t>{{header, 8}, {data, len}})) {
+        socket_.reset(nullptr);
+        return -1;
+    }
+
+    // In DATA phase
+    if (android::base::StartsWith(reinterpret_cast<const char*>(data), RESPONSE_DATA)) {
+        downloading_ = true;
+    } else {
+        downloading_ = false;
+    }
+
+    return len;
+}
+
+int ClientTcpTransport::Close() {
+    if (socket_ == nullptr) {
+        return -1;
+    }
+    socket_.reset(nullptr);
+
+    return 0;
+}
+
+int ClientTcpTransport::Reset() {
+    return Close();
+}
+
+void ClientTcpTransport::ListenFastbootSocket() {
+    while (true) {
+        socket_ = service_->Accept();
+
+        // Handshake
+        char buffer[kHandshakeLength + 1];
+        buffer[kHandshakeLength] = '\0';
+        if (socket_->ReceiveAll(buffer, kHandshakeLength, kHandshakeTimeoutMs) !=
+            kHandshakeLength) {
+            PLOG(ERROR) << "No Handshake message received";
+            socket_.reset(nullptr);
+            continue;
+        }
+
+        if (memcmp(buffer, "FB", 2) != 0) {
+            PLOG(ERROR) << "Unrecognized initialization message";
+            socket_.reset(nullptr);
+            continue;
+        }
+
+        int version = 0;
+        if (!android::base::ParseInt(buffer + 2, &version) || version < kProtocolVersion) {
+            LOG(ERROR) << "Unknown TCP protocol version " << buffer + 2
+                       << ", our version: " << kProtocolVersion;
+            socket_.reset(nullptr);
+            continue;
+        }
+
+        std::string handshake_message(android::base::StringPrintf("FB%02d", kProtocolVersion));
+        if (!socket_->Send(handshake_message.c_str(), kHandshakeLength)) {
+            PLOG(ERROR) << "Failed to send initialization message";
+            socket_.reset(nullptr);
+            continue;
+        }
+
+        break;
+    }
+}
diff --git a/fastboot/device/tcp_client.h b/fastboot/device/tcp_client.h
new file mode 100644
index 0000000..32e9834
--- /dev/null
+++ b/fastboot/device/tcp_client.h
@@ -0,0 +1,42 @@
+/*
+ * 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.
+ */
+#pragma once
+
+#include <memory>
+
+#include "socket.h"
+#include "transport.h"
+
+class ClientTcpTransport : public Transport {
+  public:
+    ClientTcpTransport();
+    ~ClientTcpTransport() override = default;
+
+    ssize_t Read(void* data, size_t len) override;
+    ssize_t Write(const void* data, size_t len) override;
+    int Close() override;
+    int Reset() override;
+
+  private:
+    void ListenFastbootSocket();
+
+    std::unique_ptr<Socket> service_;
+    std::unique_ptr<Socket> socket_;
+    uint64_t message_bytes_left_ = 0;
+    bool downloading_ = false;
+
+    DISALLOW_COPY_AND_ASSIGN(ClientTcpTransport);
+};
diff --git a/fastboot/socket.cpp b/fastboot/socket.cpp
index e56ffcf..5a14b63 100644
--- a/fastboot/socket.cpp
+++ b/fastboot/socket.cpp
@@ -54,7 +54,9 @@
     while (total < length) {
         ssize_t bytes = Receive(reinterpret_cast<char*>(data) + total, length - total, timeout_ms);
 
-        if (bytes == -1) {
+        // Returns 0 only when the peer has disconnected because our requested length is not 0. So
+        // we return immediately to avoid dead loop here.
+        if (bytes <= 0) {
             if (total == 0) {
                 return -1;
             }
diff --git a/fs_mgr/TEST_MAPPING b/fs_mgr/TEST_MAPPING
index 676f446..6cd0430 100644
--- a/fs_mgr/TEST_MAPPING
+++ b/fs_mgr/TEST_MAPPING
@@ -14,6 +14,9 @@
     },
     {
       "name": "vts_libsnapshot_test"
+    },
+    {
+      "name": "libsnapshot_fuzzer_test"
     }
   ]
 }
diff --git a/fs_mgr/libsnapshot/Android.bp b/fs_mgr/libsnapshot/Android.bp
index c191102..2783e4d 100644
--- a/fs_mgr/libsnapshot/Android.bp
+++ b/fs_mgr/libsnapshot/Android.bp
@@ -246,8 +246,8 @@
     gtest: false,
 }
 
-cc_fuzz {
-    name: "libsnapshot_fuzzer",
+cc_defaults {
+    name: "libsnapshot_fuzzer_defaults",
 
     // TODO(b/154633114): make host supported.
     // host_supported: true,
@@ -289,6 +289,11 @@
         canonical_path_from_root: false,
         local_include_dirs: ["."],
     },
+}
+
+cc_fuzz {
+    name: "libsnapshot_fuzzer",
+    defaults: ["libsnapshot_fuzzer_defaults"],
     corpus: ["corpus/*"],
     fuzz_config: {
         cc: ["android-virtual-ab+bugs@google.com"],
@@ -298,3 +303,14 @@
         fuzz_on_haiku_device: true,
     },
 }
+
+cc_test {
+    name: "libsnapshot_fuzzer_test",
+    defaults: ["libsnapshot_fuzzer_defaults"],
+    data: ["corpus/*"],
+    test_suites: [
+        "device-tests",
+    ],
+    auto_gen_config: true,
+    require_root: true,
+}
diff --git a/fs_mgr/libsnapshot/fuzz_utils.h b/fs_mgr/libsnapshot/fuzz_utils.h
index 4dc6cdc..20b13b2 100644
--- a/fs_mgr/libsnapshot/fuzz_utils.h
+++ b/fs_mgr/libsnapshot/fuzz_utils.h
@@ -68,17 +68,25 @@
     return 0;
 }
 
+// Get the field descriptor for the oneof field in the action message. If no oneof field is set,
+// return nullptr.
 template <typename Action>
-void ExecuteActionProto(typename Action::Class* module,
-                        const typename Action::Proto& action_proto) {
+const google::protobuf::FieldDescriptor* GetValueFieldDescriptor(
+        const typename Action::Proto& action_proto) {
     static auto* action_value_desc = GetProtoValueDescriptor(Action::Proto::GetDescriptor());
 
     auto* action_refl = Action::Proto::GetReflection();
     if (!action_refl->HasOneof(action_proto, action_value_desc)) {
-        return;
+        return nullptr;
     }
+    return action_refl->GetOneofFieldDescriptor(action_proto, action_value_desc);
+}
 
-    const auto* field_desc = action_refl->GetOneofFieldDescriptor(action_proto, action_value_desc);
+template <typename Action>
+void ExecuteActionProto(typename Action::ClassType* module,
+                        const typename Action::Proto& action_proto) {
+    const auto* field_desc = GetValueFieldDescriptor<Action>(action_proto);
+    if (field_desc == nullptr) return;
     auto number = field_desc->number();
     const auto& map = *Action::GetFunctionMap();
     auto it = map.find(number);
@@ -89,7 +97,7 @@
 
 template <typename Action>
 void ExecuteAllActionProtos(
-        typename Action::Class* module,
+        typename Action::ClassType* module,
         const google::protobuf::RepeatedPtrField<typename Action::Proto>& action_protos) {
     for (const auto& proto : action_protos) {
         ExecuteActionProto<Action>(module, proto);
@@ -134,53 +142,57 @@
 // ActionPerformer extracts arguments from the protobuf message, and then call FuzzFunction
 // with these arguments.
 template <typename FuzzFunction, typename Signature, typename Enabled = void>
-struct ActionPerfomer;  // undefined
+struct ActionPerformerImpl;  // undefined
 
 template <typename FuzzFunction, typename MessageProto>
-struct ActionPerfomer<
+struct ActionPerformerImpl<
         FuzzFunction, void(const MessageProto&),
         typename std::enable_if_t<std::is_base_of_v<google::protobuf::Message, MessageProto>>> {
-    static void Invoke(typename FuzzFunction::Class* module,
-                       const google::protobuf::Message& action_proto,
-                       const google::protobuf::FieldDescriptor* field_desc) {
+    static typename FuzzFunction::ReturnType Invoke(
+            typename FuzzFunction::ClassType* module, const google::protobuf::Message& action_proto,
+            const google::protobuf::FieldDescriptor* field_desc) {
         const MessageProto& arg = CheckedCast<std::remove_reference_t<MessageProto>>(
                 action_proto.GetReflection()->GetMessage(action_proto, field_desc));
-        FuzzFunction::ImplBody(module, arg);
+        return FuzzFunction::ImplBody(module, arg);
     }
 };
 
 template <typename FuzzFunction, typename Primitive>
-struct ActionPerfomer<FuzzFunction, void(Primitive),
-                      typename std::enable_if_t<std::is_arithmetic_v<Primitive>>> {
-    static void Invoke(typename FuzzFunction::Class* module,
-                       const google::protobuf::Message& action_proto,
-                       const google::protobuf::FieldDescriptor* field_desc) {
+struct ActionPerformerImpl<FuzzFunction, void(Primitive),
+                           typename std::enable_if_t<std::is_arithmetic_v<Primitive>>> {
+    static typename FuzzFunction::ReturnType Invoke(
+            typename FuzzFunction::ClassType* module, const google::protobuf::Message& action_proto,
+            const google::protobuf::FieldDescriptor* field_desc) {
         Primitive arg = std::invoke(PrimitiveGetter<Primitive>::fp, action_proto.GetReflection(),
                                     action_proto, field_desc);
-        FuzzFunction::ImplBody(module, arg);
+        return FuzzFunction::ImplBody(module, arg);
     }
 };
 
 template <typename FuzzFunction>
-struct ActionPerfomer<FuzzFunction, void()> {
-    static void Invoke(typename FuzzFunction::Class* module, const google::protobuf::Message&,
-                       const google::protobuf::FieldDescriptor*) {
-        FuzzFunction::ImplBody(module);
+struct ActionPerformerImpl<FuzzFunction, void()> {
+    static typename FuzzFunction::ReturnType Invoke(typename FuzzFunction::ClassType* module,
+                                                    const google::protobuf::Message&,
+                                                    const google::protobuf::FieldDescriptor*) {
+        return FuzzFunction::ImplBody(module);
     }
 };
 
 template <typename FuzzFunction>
-struct ActionPerfomer<FuzzFunction, void(const std::string&)> {
-    static void Invoke(typename FuzzFunction::Class* module,
-                       const google::protobuf::Message& action_proto,
-                       const google::protobuf::FieldDescriptor* field_desc) {
+struct ActionPerformerImpl<FuzzFunction, void(const std::string&)> {
+    static typename FuzzFunction::ReturnType Invoke(
+            typename FuzzFunction::ClassType* module, const google::protobuf::Message& action_proto,
+            const google::protobuf::FieldDescriptor* field_desc) {
         std::string scratch;
         const std::string& arg = action_proto.GetReflection()->GetStringReference(
                 action_proto, field_desc, &scratch);
-        FuzzFunction::ImplBody(module, arg);
+        return FuzzFunction::ImplBody(module, arg);
     }
 };
 
+template <typename FuzzFunction>
+struct ActionPerformer : ActionPerformerImpl<FuzzFunction, typename FuzzFunction::Signature> {};
+
 }  // namespace android::fuzz
 
 // Fuzz existing C++ class, ClassType, with a collection of functions under the name Action.
@@ -197,11 +209,11 @@
 //   FUZZ_CLASS(Foo, FooAction)
 // After linking functions of Foo to FooAction, execute all actions by:
 //   FooAction::ExecuteAll(foo_object, action_protos)
-#define FUZZ_CLASS(ClassType, Action)                                                            \
+#define FUZZ_CLASS(Class, Action)                                                                \
     class Action {                                                                               \
       public:                                                                                    \
         using Proto = Action##Proto;                                                             \
-        using Class = ClassType;                                                                 \
+        using ClassType = Class;                                                                 \
         using FunctionMap = android::fuzz::FunctionMap<Class>;                                   \
         static FunctionMap* GetFunctionMap() {                                                   \
             static Action::FunctionMap map;                                                      \
@@ -225,29 +237,33 @@
 // }
 // class Foo { public: void DoAwesomeFoo(bool arg); };
 // FUZZ_OBJECT(FooAction, Foo);
-// FUZZ_FUNCTION(FooAction, DoFoo, module, bool arg) {
+// FUZZ_FUNCTION(FooAction, DoFoo, void, IFoo* module, bool arg) {
 //   module->DoAwesomeFoo(arg);
 // }
 // The name DoFoo is the camel case name of the action in protobuf definition of FooActionProto.
-#define FUZZ_FUNCTION(Action, FunctionName, module, ...)                                         \
-    class FUZZ_FUNCTION_CLASS_NAME(Action, FunctionName) {                                       \
-      public:                                                                                    \
-        using Class = Action::Class;                                                             \
-        static void ImplBody(Action::Class*, ##__VA_ARGS__);                                     \
-                                                                                                 \
-      private:                                                                                   \
-        static bool registered_;                                                                 \
-    };                                                                                           \
-    auto FUZZ_FUNCTION_CLASS_NAME(Action, FunctionName)::registered_ = ([] {                     \
-        auto tag = Action::Proto::ValueCase::FUZZ_FUNCTION_TAG_NAME(FunctionName);               \
-        auto func =                                                                              \
-                &::android::fuzz::ActionPerfomer<FUZZ_FUNCTION_CLASS_NAME(Action, FunctionName), \
-                                                 void(__VA_ARGS__)>::Invoke;                     \
-        Action::GetFunctionMap()->CheckEmplace(tag, func);                                       \
-        return true;                                                                             \
-    })();                                                                                        \
-    void FUZZ_FUNCTION_CLASS_NAME(Action, FunctionName)::ImplBody(Action::Class* module,         \
-                                                                  ##__VA_ARGS__)
+#define FUZZ_FUNCTION(Action, FunctionName, Return, ModuleArg, ...)             \
+    class FUZZ_FUNCTION_CLASS_NAME(Action, FunctionName) {                      \
+      public:                                                                   \
+        using ActionType = Action;                                              \
+        using ClassType = Action::ClassType;                                    \
+        using ReturnType = Return;                                              \
+        using Signature = void(__VA_ARGS__);                                    \
+        static constexpr const char name[] = #FunctionName;                     \
+        static constexpr const auto tag =                                       \
+                Action::Proto::ValueCase::FUZZ_FUNCTION_TAG_NAME(FunctionName); \
+        static ReturnType ImplBody(ModuleArg, ##__VA_ARGS__);                   \
+                                                                                \
+      private:                                                                  \
+        static bool registered_;                                                \
+    };                                                                          \
+    auto FUZZ_FUNCTION_CLASS_NAME(Action, FunctionName)::registered_ = ([] {    \
+        auto tag = FUZZ_FUNCTION_CLASS_NAME(Action, FunctionName)::tag;         \
+        auto func = &::android::fuzz::ActionPerformer<FUZZ_FUNCTION_CLASS_NAME( \
+                Action, FunctionName)>::Invoke;                                 \
+        Action::GetFunctionMap()->CheckEmplace(tag, func);                      \
+        return true;                                                            \
+    })();                                                                       \
+    Return FUZZ_FUNCTION_CLASS_NAME(Action, FunctionName)::ImplBody(ModuleArg, ##__VA_ARGS__)
 
 // Implement a simple action by linking it to the function with the same name. Example:
 // message FooActionProto {
@@ -261,5 +277,9 @@
 // FUZZ_FUNCTION(FooAction, DoBar);
 // The name DoBar is the camel case name of the action in protobuf definition of FooActionProto, and
 // also the name of the function of Foo.
-#define FUZZ_SIMPLE_FUNCTION(Action, FunctionName) \
-    FUZZ_FUNCTION(Action, FunctionName, module) { (void)module->FunctionName(); }
+#define FUZZ_SIMPLE_FUNCTION(Action, FunctionName)                            \
+    FUZZ_FUNCTION(Action, FunctionName,                                       \
+                  decltype(std::declval<Action::ClassType>().FunctionName()), \
+                  Action::ClassType* module) {                                \
+        return module->FunctionName();                                        \
+    }
diff --git a/fs_mgr/libsnapshot/snapshot_fuzz.cpp b/fs_mgr/libsnapshot/snapshot_fuzz.cpp
index 1e90ace..5b145c3 100644
--- a/fs_mgr/libsnapshot/snapshot_fuzz.cpp
+++ b/fs_mgr/libsnapshot/snapshot_fuzz.cpp
@@ -21,14 +21,21 @@
 #include <tuple>
 
 #include <android-base/logging.h>
+#include <android-base/properties.h>
+#include <android-base/result.h>
+#include <gtest/gtest.h>
 #include <src/libfuzzer/libfuzzer_macro.h>
 #include <storage_literals/storage_literals.h>
 
 #include "fuzz_utils.h"
 #include "snapshot_fuzz_utils.h"
 
+using android::base::Error;
+using android::base::GetBoolProperty;
 using android::base::LogId;
 using android::base::LogSeverity;
+using android::base::ReadFileToString;
+using android::base::Result;
 using android::base::SetLogger;
 using android::base::StderrLogger;
 using android::base::StdioLogger;
@@ -37,6 +44,8 @@
 using android::snapshot::SnapshotFuzzData;
 using android::snapshot::SnapshotFuzzEnv;
 using chromeos_update_engine::DeltaArchiveManifest;
+using google::protobuf::FieldDescriptor;
+using google::protobuf::Message;
 using google::protobuf::RepeatedPtrField;
 
 // Avoid linking to libgsi since it needs disk I/O.
@@ -74,48 +83,49 @@
 FUZZ_SIMPLE_FUNCTION(SnapshotManagerAction, EnsureMetadataMounted);
 FUZZ_SIMPLE_FUNCTION(SnapshotManagerAction, GetSnapshotMergeStatsInstance);
 
-#define SNAPSHOT_FUZZ_FUNCTION(FunctionName, ...) \
-    FUZZ_FUNCTION(SnapshotManagerAction, FunctionName, snapshot, ##__VA_ARGS__)
+#define SNAPSHOT_FUZZ_FUNCTION(FunctionName, ReturnType, ...)                                  \
+    FUZZ_FUNCTION(SnapshotManagerAction, FunctionName, ReturnType, ISnapshotManager* snapshot, \
+                  ##__VA_ARGS__)
 
-SNAPSHOT_FUZZ_FUNCTION(FinishedSnapshotWrites, bool wipe) {
-    (void)snapshot->FinishedSnapshotWrites(wipe);
+SNAPSHOT_FUZZ_FUNCTION(FinishedSnapshotWrites, bool, bool wipe) {
+    return snapshot->FinishedSnapshotWrites(wipe);
 }
 
-SNAPSHOT_FUZZ_FUNCTION(ProcessUpdateState, const ProcessUpdateStateArgs& args) {
+SNAPSHOT_FUZZ_FUNCTION(ProcessUpdateState, bool, const ProcessUpdateStateArgs& args) {
     std::function<bool()> before_cancel;
     if (args.has_before_cancel()) {
         before_cancel = [&]() { return args.fail_before_cancel(); };
     }
-    (void)snapshot->ProcessUpdateState({}, before_cancel);
+    return snapshot->ProcessUpdateState({}, before_cancel);
 }
 
-SNAPSHOT_FUZZ_FUNCTION(GetUpdateState, bool has_progress_arg) {
+SNAPSHOT_FUZZ_FUNCTION(GetUpdateState, UpdateState, bool has_progress_arg) {
     double progress;
-    (void)snapshot->GetUpdateState(has_progress_arg ? &progress : nullptr);
+    return snapshot->GetUpdateState(has_progress_arg ? &progress : nullptr);
 }
 
-SNAPSHOT_FUZZ_FUNCTION(HandleImminentDataWipe, bool has_callback) {
+SNAPSHOT_FUZZ_FUNCTION(HandleImminentDataWipe, bool, bool has_callback) {
     std::function<void()> callback;
     if (has_callback) {
         callback = []() {};
     }
-    (void)snapshot->HandleImminentDataWipe(callback);
+    return snapshot->HandleImminentDataWipe(callback);
 }
 
-SNAPSHOT_FUZZ_FUNCTION(Dump) {
+SNAPSHOT_FUZZ_FUNCTION(Dump, bool) {
     std::stringstream ss;
-    (void)snapshot->Dump(ss);
+    return snapshot->Dump(ss);
 }
 
-SNAPSHOT_FUZZ_FUNCTION(CreateUpdateSnapshots, const DeltaArchiveManifest& manifest) {
-    (void)snapshot->CreateUpdateSnapshots(manifest);
+SNAPSHOT_FUZZ_FUNCTION(CreateUpdateSnapshots, bool, const DeltaArchiveManifest& manifest) {
+    return snapshot->CreateUpdateSnapshots(manifest);
 }
 
-SNAPSHOT_FUZZ_FUNCTION(UnmapUpdateSnapshot, const std::string& name) {
-    (void)snapshot->UnmapUpdateSnapshot(name);
+SNAPSHOT_FUZZ_FUNCTION(UnmapUpdateSnapshot, bool, const std::string& name) {
+    return snapshot->UnmapUpdateSnapshot(name);
 }
 
-SNAPSHOT_FUZZ_FUNCTION(CreateLogicalAndSnapshotPartitions,
+SNAPSHOT_FUZZ_FUNCTION(CreateLogicalAndSnapshotPartitions, bool,
                        const CreateLogicalAndSnapshotPartitionsArgs& args) {
     const std::string* super;
     if (args.use_correct_super()) {
@@ -123,20 +133,21 @@
     } else {
         super = &args.super();
     }
-    (void)snapshot->CreateLogicalAndSnapshotPartitions(
+    return snapshot->CreateLogicalAndSnapshotPartitions(
             *super, std::chrono::milliseconds(args.timeout_millis()));
 }
 
-SNAPSHOT_FUZZ_FUNCTION(RecoveryCreateSnapshotDevicesWithMetadata,
+SNAPSHOT_FUZZ_FUNCTION(RecoveryCreateSnapshotDevicesWithMetadata, CreateResult,
                        const RecoveryCreateSnapshotDevicesArgs& args) {
     std::unique_ptr<AutoDevice> device;
     if (args.has_metadata_device_object()) {
         device = std::make_unique<DummyAutoDevice>(args.metadata_mounted());
     }
-    (void)snapshot->RecoveryCreateSnapshotDevices(device);
+    return snapshot->RecoveryCreateSnapshotDevices(device);
 }
 
-SNAPSHOT_FUZZ_FUNCTION(MapUpdateSnapshot, const CreateLogicalPartitionParamsProto& params_proto) {
+SNAPSHOT_FUZZ_FUNCTION(MapUpdateSnapshot, bool,
+                       const CreateLogicalPartitionParamsProto& params_proto) {
     auto partition_opener = std::make_unique<TestPartitionOpener>(GetSnapshotFuzzEnv()->super());
     CreateLogicalPartitionParams params;
     if (params_proto.use_correct_super()) {
@@ -153,10 +164,10 @@
     params.device_name = params_proto.device_name();
     params.partition_opener = partition_opener.get();
     std::string path;
-    (void)snapshot->MapUpdateSnapshot(params, &path);
+    return snapshot->MapUpdateSnapshot(params, &path);
 }
 
-SNAPSHOT_FUZZ_FUNCTION(SwitchSlot) {
+SNAPSHOT_FUZZ_FUNCTION(SwitchSlot, void) {
     (void)snapshot;
     CHECK(current_module != nullptr);
     CHECK(current_module->device_info != nullptr);
@@ -194,7 +205,8 @@
 }
 // Stop logging (except fatal messages) after global initialization. This is only done once.
 int StopLoggingAfterGlobalInit() {
-    [[maybe_unused]] static protobuf_mutator::protobuf::LogSilencer log_silincer;
+    (void)GetSnapshotFuzzEnv();
+    [[maybe_unused]] static protobuf_mutator::protobuf::LogSilencer log_silencer;
     SetLogger(&FatalOnlyLogger);
     return 0;
 }
@@ -202,15 +214,10 @@
 SnapshotFuzzEnv* GetSnapshotFuzzEnv() {
     [[maybe_unused]] static auto allow_logging = AllowLoggingDuringGlobalInit();
     static SnapshotFuzzEnv env;
-    [[maybe_unused]] static auto stop_logging = StopLoggingAfterGlobalInit();
     return &env;
 }
 
-}  // namespace android::snapshot
-
-DEFINE_PROTO_FUZZER(const SnapshotFuzzData& snapshot_fuzz_data) {
-    using namespace android::snapshot;
-
+SnapshotTestModule SetUpTest(const SnapshotFuzzData& snapshot_fuzz_data) {
     current_data = &snapshot_fuzz_data;
 
     auto env = GetSnapshotFuzzEnv();
@@ -219,9 +226,127 @@
     auto test_module = env->CheckCreateSnapshotManager(snapshot_fuzz_data);
     current_module = &test_module;
     CHECK(test_module.snapshot);
+    return test_module;
+}
 
-    SnapshotManagerAction::ExecuteAll(test_module.snapshot.get(), snapshot_fuzz_data.actions());
-
+void TearDownTest() {
     current_module = nullptr;
     current_data = nullptr;
 }
+
+}  // namespace android::snapshot
+
+DEFINE_PROTO_FUZZER(const SnapshotFuzzData& snapshot_fuzz_data) {
+    using namespace android::snapshot;
+
+    [[maybe_unused]] static auto stop_logging = StopLoggingAfterGlobalInit();
+    auto test_module = SetUpTest(snapshot_fuzz_data);
+    SnapshotManagerAction::ExecuteAll(test_module.snapshot.get(), snapshot_fuzz_data.actions());
+    TearDownTest();
+}
+
+namespace android::snapshot {
+
+// Work-around to cast a 'void' value to Result<void>.
+template <typename T>
+struct GoodResult {
+    template <typename F>
+    static Result<T> Cast(F&& f) {
+        return f();
+    }
+};
+
+template <>
+struct GoodResult<void> {
+    template <typename F>
+    static Result<void> Cast(F&& f) {
+        f();
+        return {};
+    }
+};
+
+class LibsnapshotFuzzerTest : public ::testing::Test {
+  protected:
+    static void SetUpTestCase() {
+        // Do initialization once.
+        (void)GetSnapshotFuzzEnv();
+    }
+    void SetUp() override {
+        bool is_virtual_ab = GetBoolProperty("ro.virtual_ab.enabled", false);
+        if (!is_virtual_ab) GTEST_SKIP() << "Test only runs on Virtual A/B devices.";
+    }
+    void SetUpFuzzData(const std::string& fn) {
+        auto path = android::base::GetExecutableDirectory() + "/corpus/"s + fn;
+        std::string proto_text;
+        ASSERT_TRUE(ReadFileToString(path, &proto_text));
+        snapshot_fuzz_data_ = std::make_unique<SnapshotFuzzData>();
+        ASSERT_TRUE(google::protobuf::TextFormat::ParseFromString(proto_text,
+                                                                  snapshot_fuzz_data_.get()));
+        test_module_ = android::snapshot::SetUpTest(*snapshot_fuzz_data_);
+    }
+    void TearDown() override { android::snapshot::TearDownTest(); }
+    template <typename FuzzFunction>
+    Result<typename FuzzFunction::ReturnType> Execute(int action_index) {
+        if (action_index >= snapshot_fuzz_data_->actions_size()) {
+            return Error() << "Index " << action_index << " is out of bounds ("
+                           << snapshot_fuzz_data_->actions_size() << " actions in corpus";
+        }
+        const auto& action_proto = snapshot_fuzz_data_->actions(action_index);
+        const auto* field_desc =
+                android::fuzz::GetValueFieldDescriptor<typename FuzzFunction::ActionType>(
+                        action_proto);
+        if (field_desc == nullptr) {
+            return Error() << "Action at index " << action_index << " has no value defined.";
+        }
+        if (FuzzFunction::tag != field_desc->number()) {
+            return Error() << "Action at index " << action_index << " is expected to be "
+                           << FuzzFunction::name << ", but it is " << field_desc->name()
+                           << " in corpus.";
+        }
+        return GoodResult<typename FuzzFunction::ReturnType>::Cast([&]() {
+            return android::fuzz::ActionPerformer<FuzzFunction>::Invoke(test_module_.snapshot.get(),
+                                                                        action_proto, field_desc);
+        });
+    }
+
+    std::unique_ptr<SnapshotFuzzData> snapshot_fuzz_data_;
+    SnapshotTestModule test_module_;
+};
+
+#define SNAPSHOT_FUZZ_FN_NAME(name) FUZZ_FUNCTION_CLASS_NAME(SnapshotManagerAction, name)
+
+MATCHER_P(ResultIs, expected, "") {
+    if (!arg.ok()) {
+        *result_listener << arg.error();
+        return false;
+    }
+    *result_listener << "expected: " << expected;
+    return arg.value() == expected;
+}
+
+#define ASSERT_RESULT_TRUE(actual) ASSERT_THAT(actual, ResultIs(true))
+
+// Check that launch_device.txt is executed correctly.
+TEST_F(LibsnapshotFuzzerTest, LaunchDevice) {
+    SetUpFuzzData("launch_device.txt");
+
+    int i = 0;
+    ASSERT_RESULT_TRUE(Execute<SNAPSHOT_FUZZ_FN_NAME(BeginUpdate)>(i++));
+    ASSERT_RESULT_TRUE(Execute<SNAPSHOT_FUZZ_FN_NAME(CreateUpdateSnapshots)>(i++));
+    ASSERT_RESULT_TRUE(Execute<SNAPSHOT_FUZZ_FN_NAME(MapUpdateSnapshot)>(i++)) << "sys_b";
+    ASSERT_RESULT_TRUE(Execute<SNAPSHOT_FUZZ_FN_NAME(MapUpdateSnapshot)>(i++)) << "vnd_b";
+    ASSERT_RESULT_TRUE(Execute<SNAPSHOT_FUZZ_FN_NAME(MapUpdateSnapshot)>(i++)) << "prd_b";
+    ASSERT_RESULT_TRUE(Execute<SNAPSHOT_FUZZ_FN_NAME(FinishedSnapshotWrites)>(i++));
+    ASSERT_RESULT_TRUE(Execute<SNAPSHOT_FUZZ_FN_NAME(UnmapUpdateSnapshot)>(i++)) << "sys_b";
+    ASSERT_RESULT_TRUE(Execute<SNAPSHOT_FUZZ_FN_NAME(UnmapUpdateSnapshot)>(i++)) << "vnd_b";
+    ASSERT_RESULT_TRUE(Execute<SNAPSHOT_FUZZ_FN_NAME(UnmapUpdateSnapshot)>(i++)) << "prd_b";
+    ASSERT_RESULT_OK(Execute<SNAPSHOT_FUZZ_FN_NAME(SwitchSlot)>(i++));
+    ASSERT_EQ("_b", test_module_.device_info->GetSlotSuffix());
+    ASSERT_RESULT_TRUE(Execute<SNAPSHOT_FUZZ_FN_NAME(NeedSnapshotsInFirstStageMount)>(i++));
+    ASSERT_RESULT_TRUE(Execute<SNAPSHOT_FUZZ_FN_NAME(CreateLogicalAndSnapshotPartitions)>(i++));
+    ASSERT_RESULT_TRUE(Execute<SNAPSHOT_FUZZ_FN_NAME(InitiateMerge)>(i++));
+    ASSERT_RESULT_TRUE(Execute<SNAPSHOT_FUZZ_FN_NAME(ProcessUpdateState)>(i++));
+    ASSERT_EQ(i, snapshot_fuzz_data_->actions_size()) << "Not all actions are executed.";
+}
+
+}  // namespace android::snapshot
diff --git a/fs_mgr/libsnapshot/snapshot_fuzz_utils.cpp b/fs_mgr/libsnapshot/snapshot_fuzz_utils.cpp
index c9f1ab0..8926535 100644
--- a/fs_mgr/libsnapshot/snapshot_fuzz_utils.cpp
+++ b/fs_mgr/libsnapshot/snapshot_fuzz_utils.cpp
@@ -27,7 +27,6 @@
 #include <android-base/properties.h>
 #include <android-base/stringprintf.h>
 #include <android-base/strings.h>
-#include <cutils/properties.h>
 #include <fs_mgr.h>
 #include <libsnapshot/auto_device.h>
 #include <libsnapshot/snapshot.h>
@@ -165,14 +164,6 @@
     reinterpret_cast<PropertyList*>(cookie)->insert(key);
 }
 
-void CheckUnsetGsidProps() {
-    PropertyList list;
-    property_list(&InsertProperty, reinterpret_cast<void*>(&list));
-    for (const auto& key : list) {
-        SetProperty(key, "");
-    }
-}
-
 // Attempt to delete all devices that is based on dev_name, including itself.
 void CheckDeleteDeviceMapperTree(const std::string& dev_name, bool known_allow_delete = false,
                                  uint64_t depth = 100) {
@@ -344,7 +335,6 @@
 };
 
 SnapshotFuzzEnv::SnapshotFuzzEnv() {
-    CheckUnsetGsidProps();
     CheckCleanupDeviceMapperDevices();
     CheckDetachLoopDevices();
     CheckUmountAll();
@@ -368,7 +358,6 @@
 }
 
 SnapshotFuzzEnv::~SnapshotFuzzEnv() {
-    CheckUnsetGsidProps();
     CheckCleanupDeviceMapperDevices();
     mounted_data_ = nullptr;
     auto_delete_data_mount_point_ = nullptr;
@@ -396,7 +385,7 @@
         const std::string& metadata_dir, const std::string& data_dir) {
     PCHECK(Mkdir(metadata_dir));
     PCHECK(Mkdir(data_dir));
-    return ImageManager::Open(metadata_dir, data_dir);
+    return SnapshotFuzzImageManager::Open(metadata_dir, data_dir);
 }
 
 // Helper to create a loop device for a file.
@@ -507,4 +496,21 @@
     return std::make_unique<AutoUnmount>(mount_point);
 }
 
+SnapshotFuzzImageManager::~SnapshotFuzzImageManager() {
+    // Remove relevant gsid.mapped_images.* props.
+    for (const auto& name : mapped_) {
+        CHECK(UnmapImageIfExists(name)) << "Cannot unmap " << name;
+    }
+}
+
+bool SnapshotFuzzImageManager::MapImageDevice(const std::string& name,
+                                              const std::chrono::milliseconds& timeout_ms,
+                                              std::string* path) {
+    if (impl_->MapImageDevice(name, timeout_ms, path)) {
+        mapped_.insert(name);
+        return true;
+    }
+    return false;
+}
+
 }  // namespace android::snapshot
diff --git a/fs_mgr/libsnapshot/snapshot_fuzz_utils.h b/fs_mgr/libsnapshot/snapshot_fuzz_utils.h
index 2405088..fa327b8 100644
--- a/fs_mgr/libsnapshot/snapshot_fuzz_utils.h
+++ b/fs_mgr/libsnapshot/snapshot_fuzz_utils.h
@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#include <memory>
+#include <set>
 #include <string>
 
 #include <android-base/file.h>
@@ -134,4 +136,68 @@
     bool CurrentSlotIsA() const { return data_->slot_suffix_is_a() != switched_slot_; }
 };
 
+// A spy class on ImageManager implementation. Upon destruction, unmaps all images
+// map through this object.
+class SnapshotFuzzImageManager : public android::fiemap::IImageManager {
+  public:
+    static std::unique_ptr<SnapshotFuzzImageManager> Open(const std::string& metadata_dir,
+                                                          const std::string& data_dir) {
+        auto impl = android::fiemap::ImageManager::Open(metadata_dir, data_dir);
+        if (impl == nullptr) return nullptr;
+        return std::unique_ptr<SnapshotFuzzImageManager>(
+                new SnapshotFuzzImageManager(std::move(impl)));
+    }
+
+    ~SnapshotFuzzImageManager();
+
+    // Spied APIs.
+    bool MapImageDevice(const std::string& name, const std::chrono::milliseconds& timeout_ms,
+                        std::string* path) override;
+
+    // Other functions call through.
+    android::fiemap::FiemapStatus CreateBackingImage(
+            const std::string& name, uint64_t size, int flags,
+            std::function<bool(uint64_t, uint64_t)>&& on_progress) override {
+        return impl_->CreateBackingImage(name, size, flags, std::move(on_progress));
+    }
+    bool DeleteBackingImage(const std::string& name) override {
+        return impl_->DeleteBackingImage(name);
+    }
+    bool UnmapImageDevice(const std::string& name) override {
+        return impl_->UnmapImageDevice(name);
+    }
+    bool BackingImageExists(const std::string& name) override {
+        return impl_->BackingImageExists(name);
+    }
+    bool IsImageMapped(const std::string& name) override { return impl_->IsImageMapped(name); }
+    bool MapImageWithDeviceMapper(const IPartitionOpener& opener, const std::string& name,
+                                  std::string* dev) override {
+        return impl_->MapImageWithDeviceMapper(opener, name, dev);
+    }
+    bool GetMappedImageDevice(const std::string& name, std::string* device) override {
+        return impl_->GetMappedImageDevice(name, device);
+    }
+    bool MapAllImages(const std::function<bool(std::set<std::string>)>& init) override {
+        return impl_->MapAllImages(init);
+    }
+    bool DisableImage(const std::string& name) override { return impl_->DisableImage(name); }
+    bool RemoveDisabledImages() override { return impl_->RemoveDisabledImages(); }
+    std::vector<std::string> GetAllBackingImages() override { return impl_->GetAllBackingImages(); }
+    android::fiemap::FiemapStatus ZeroFillNewImage(const std::string& name,
+                                                   uint64_t bytes) override {
+        return impl_->ZeroFillNewImage(name, bytes);
+    }
+    bool RemoveAllImages() override { return impl_->RemoveAllImages(); }
+    bool UnmapImageIfExists(const std::string& name) override {
+        return impl_->UnmapImageIfExists(name);
+    }
+
+  private:
+    std::unique_ptr<android::fiemap::IImageManager> impl_;
+    std::set<std::string> mapped_;
+
+    SnapshotFuzzImageManager(std::unique_ptr<android::fiemap::IImageManager>&& impl)
+        : impl_(std::move(impl)) {}
+};
+
 }  // namespace android::snapshot
diff --git a/init/test_kill_services/AndroidTest.xml b/init/test_kill_services/AndroidTest.xml
index c1dcd59..8018efa 100644
--- a/init/test_kill_services/AndroidTest.xml
+++ b/init/test_kill_services/AndroidTest.xml
@@ -18,7 +18,16 @@
     <option name="test-suite-tag" value="apct-native" />
 
     <!-- cannot be autogenerated: b/153565474 -->
-    <target_preparer class="com.android.tradefed.targetprep.RebootTargetPreparer" />
+    <target_preparer class="com.android.tradefed.targetprep.RebootTargetPreparer">
+        <!-- flake mitigation, in case device is in bad state-->
+        <option name="pre-reboot" value="true" />
+        <!-- sometimes device gets into bad state, and we don't detect it in this test,
+          so the test succeeds and the next test fails. This is a really bad result, so
+          to avoid that, making sure we reboot the device again before running any more
+          tests.
+          TODO(b/152556737): add metrics for successful device recovery -->
+        <option name="post-reboot" value="true" />
+    </target_preparer>
 
     <target_preparer class="com.android.tradefed.targetprep.RootTargetPreparer"/>
 
diff --git a/libutils/Android.bp b/libutils/Android.bp
index 2dbfb70..0f7044a 100644
--- a/libutils/Android.bp
+++ b/libutils/Android.bp
@@ -175,8 +175,8 @@
     ],
 
     shared_libs: [
-         "libutils",
-         "libbacktrace",
+        "libutils",
+        "libbacktrace",
     ],
 
     target: {
@@ -194,6 +194,45 @@
     },
 }
 
+cc_defaults {
+    name: "libutils_fuzz_defaults",
+    host_supported: true,
+    shared_libs: [
+        "libutils",
+        "libbase",
+    ],
+}
+
+cc_fuzz {
+    name: "libutils_fuzz_bitset",
+    defaults: ["libutils_fuzz_defaults"],
+    srcs: ["BitSet_fuzz.cpp"],
+}
+
+cc_fuzz {
+    name: "libutils_fuzz_filemap",
+    defaults: ["libutils_fuzz_defaults"],
+    srcs: ["FileMap_fuzz.cpp"],
+}
+
+cc_fuzz {
+    name: "libutils_fuzz_string8",
+    defaults: ["libutils_fuzz_defaults"],
+    srcs: ["String8_fuzz.cpp"],
+}
+
+cc_fuzz {
+    name: "libutils_fuzz_string16",
+    defaults: ["libutils_fuzz_defaults"],
+    srcs: ["String16_fuzz.cpp"],
+}
+
+cc_fuzz {
+    name: "libutils_fuzz_vector",
+    defaults: ["libutils_fuzz_defaults"],
+    srcs: ["Vector_fuzz.cpp"],
+}
+
 cc_test {
     name: "libutils_test",
     host_supported: true,
diff --git a/libutils/BitSet_fuzz.cpp b/libutils/BitSet_fuzz.cpp
new file mode 100644
index 0000000..2e6043c
--- /dev/null
+++ b/libutils/BitSet_fuzz.cpp
@@ -0,0 +1,70 @@
+/*
+ * Copyright 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 <functional>
+
+#include "fuzzer/FuzzedDataProvider.h"
+#include "utils/BitSet.h"
+static constexpr uint8_t MAX_OPERATIONS = 50;
+
+// We need to handle both 32 and 64 bit bitsets, so we use a function template
+// here. Sadly, std::function can't be generic, so we generate a vector of
+// std::functions using this function.
+template <typename T>
+std::vector<std::function<void(T, uint32_t)>> getOperationsForType() {
+    return {
+            [](T bs, uint32_t val) -> void { bs.markBit(val); },
+            [](T bs, uint32_t val) -> void { bs.valueForBit(val); },
+            [](T bs, uint32_t val) -> void { bs.hasBit(val); },
+            [](T bs, uint32_t val) -> void { bs.clearBit(val); },
+            [](T bs, uint32_t val) -> void { bs.getIndexOfBit(val); },
+            [](T bs, uint32_t) -> void { bs.clearFirstMarkedBit(); },
+            [](T bs, uint32_t) -> void { bs.markFirstUnmarkedBit(); },
+            [](T bs, uint32_t) -> void { bs.clearLastMarkedBit(); },
+            [](T bs, uint32_t) -> void { bs.clear(); },
+            [](T bs, uint32_t) -> void { bs.count(); },
+            [](T bs, uint32_t) -> void { bs.isEmpty(); },
+            [](T bs, uint32_t) -> void { bs.isFull(); },
+            [](T bs, uint32_t) -> void { bs.firstMarkedBit(); },
+            [](T bs, uint32_t) -> void { bs.lastMarkedBit(); },
+    };
+}
+
+// Our operations for 32 and 64 bit bitsets
+static const std::vector<std::function<void(android::BitSet32, uint32_t)>> thirtyTwoBitOps =
+        getOperationsForType<android::BitSet32>();
+static const std::vector<std::function<void(android::BitSet64, uint32_t)>> sixtyFourBitOps =
+        getOperationsForType<android::BitSet64>();
+
+void runOperationFor32Bit(android::BitSet32 bs, uint32_t bit, uint8_t operation) {
+    thirtyTwoBitOps[operation](bs, bit);
+}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+    FuzzedDataProvider dataProvider(data, size);
+    uint32_t thirty_two_base = dataProvider.ConsumeIntegral<uint32_t>();
+    uint64_t sixty_four_base = dataProvider.ConsumeIntegral<uint64_t>();
+    android::BitSet32 b1 = android::BitSet32(thirty_two_base);
+    android::BitSet64 b2 = android::BitSet64(sixty_four_base);
+
+    size_t opsRun = 0;
+    while (dataProvider.remaining_bytes() > 0 && opsRun++ < MAX_OPERATIONS) {
+        uint32_t bit = dataProvider.ConsumeIntegral<uint32_t>();
+        uint8_t op = dataProvider.ConsumeIntegral<uint8_t>();
+        thirtyTwoBitOps[op % thirtyTwoBitOps.size()](b1, bit);
+        sixtyFourBitOps[op % sixtyFourBitOps.size()](b2, bit);
+    }
+    return 0;
+}
diff --git a/libutils/FileMap_fuzz.cpp b/libutils/FileMap_fuzz.cpp
new file mode 100644
index 0000000..d800564
--- /dev/null
+++ b/libutils/FileMap_fuzz.cpp
@@ -0,0 +1,50 @@
+/*
+ * Copyright 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 <iostream>
+
+#include "android-base/file.h"
+#include "fuzzer/FuzzedDataProvider.h"
+#include "utils/FileMap.h"
+
+static constexpr uint16_t MAX_STR_SIZE = 256;
+static constexpr uint8_t MAX_FILENAME_SIZE = 32;
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+    FuzzedDataProvider dataProvider(data, size);
+    TemporaryFile tf;
+    // Generate file contents
+    std::string contents = dataProvider.ConsumeRandomLengthString(MAX_STR_SIZE);
+    // If we have string contents, dump them into the file.
+    // Otherwise, just leave it as an empty file.
+    if (contents.length() > 0) {
+        const char* bytes = contents.c_str();
+        android::base::WriteStringToFd(bytes, tf.fd);
+    }
+    android::FileMap m;
+    // Generate create() params
+    std::string orig_name = dataProvider.ConsumeRandomLengthString(MAX_FILENAME_SIZE);
+    size_t length = dataProvider.ConsumeIntegralInRange<size_t>(1, SIZE_MAX);
+    off64_t offset = dataProvider.ConsumeIntegralInRange<off64_t>(1, INT64_MAX);
+    bool read_only = dataProvider.ConsumeBool();
+    m.create(orig_name.c_str(), tf.fd, offset, length, read_only);
+    m.getDataOffset();
+    m.getFileName();
+    m.getDataLength();
+    m.getDataPtr();
+    int enum_index = dataProvider.ConsumeIntegral<int>();
+    m.advise(static_cast<android::FileMap::MapAdvice>(enum_index));
+    return 0;
+}
diff --git a/libutils/String16_fuzz.cpp b/libutils/String16_fuzz.cpp
new file mode 100644
index 0000000..63c2800
--- /dev/null
+++ b/libutils/String16_fuzz.cpp
@@ -0,0 +1,122 @@
+/*
+ * Copyright 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 <iostream>
+
+#include "fuzzer/FuzzedDataProvider.h"
+#include "utils/String16.h"
+static constexpr int MAX_STRING_BYTES = 256;
+static constexpr uint8_t MAX_OPERATIONS = 50;
+
+std::vector<std::function<void(FuzzedDataProvider&, android::String16, android::String16)>>
+        operations = {
+
+                // Bytes and size
+                ([](FuzzedDataProvider&, android::String16 str1, android::String16) -> void {
+                    str1.string();
+                }),
+                ([](FuzzedDataProvider&, android::String16 str1, android::String16) -> void {
+                    str1.isStaticString();
+                }),
+                ([](FuzzedDataProvider&, android::String16 str1, android::String16) -> void {
+                    str1.size();
+                }),
+
+                // Casing
+                ([](FuzzedDataProvider&, android::String16 str1, android::String16) -> void {
+                    str1.makeLower();
+                }),
+
+                // Comparison
+                ([](FuzzedDataProvider&, android::String16 str1, android::String16 str2) -> void {
+                    str1.startsWith(str2);
+                }),
+                ([](FuzzedDataProvider&, android::String16 str1, android::String16 str2) -> void {
+                    str1.contains(str2.string());
+                }),
+                ([](FuzzedDataProvider&, android::String16 str1, android::String16 str2) -> void {
+                    str1.compare(str2);
+                }),
+
+                // Append and format
+                ([](FuzzedDataProvider&, android::String16 str1, android::String16 str2) -> void {
+                    str1.append(str2);
+                }),
+                ([](FuzzedDataProvider& dataProvider, android::String16 str1,
+                    android::String16 str2) -> void {
+                    int pos = dataProvider.ConsumeIntegralInRange<int>(0, str1.size());
+                    str1.insert(pos, str2.string());
+                }),
+
+                // Find and replace operations
+                ([](FuzzedDataProvider& dataProvider, android::String16 str1,
+                    android::String16) -> void {
+                    char16_t findChar = dataProvider.ConsumeIntegral<char16_t>();
+                    str1.findFirst(findChar);
+                }),
+                ([](FuzzedDataProvider& dataProvider, android::String16 str1,
+                    android::String16) -> void {
+                    char16_t findChar = dataProvider.ConsumeIntegral<char16_t>();
+                    str1.findLast(findChar);
+                }),
+                ([](FuzzedDataProvider& dataProvider, android::String16 str1,
+                    android::String16) -> void {
+                    char16_t findChar = dataProvider.ConsumeIntegral<char16_t>();
+                    char16_t replaceChar = dataProvider.ConsumeIntegral<char16_t>();
+                    str1.replaceAll(findChar, replaceChar);
+                }),
+                ([](FuzzedDataProvider& dataProvider, android::String16 str1,
+                    android::String16) -> void {
+                    size_t len = dataProvider.ConsumeIntegral<size_t>();
+                    size_t begin = dataProvider.ConsumeIntegral<size_t>();
+                    str1.remove(len, begin);
+                }),
+};
+
+void callFunc(uint8_t index, FuzzedDataProvider& dataProvider, android::String16 str1,
+              android::String16 str2) {
+    operations[index](dataProvider, str1, str2);
+}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+    FuzzedDataProvider dataProvider(data, size);
+    // We're generating two char vectors.
+    // First, generate lengths.
+    const size_t kVecOneLen = dataProvider.ConsumeIntegralInRange<size_t>(1, MAX_STRING_BYTES);
+    const size_t kVecTwoLen = dataProvider.ConsumeIntegralInRange<size_t>(1, MAX_STRING_BYTES);
+
+    // Next, populate the vectors
+    std::vector<char> vec = dataProvider.ConsumeBytesWithTerminator<char>(kVecOneLen);
+    std::vector<char> vec_two = dataProvider.ConsumeBytesWithTerminator<char>(kVecTwoLen);
+
+    // Get pointers to their data
+    char* char_one = vec.data();
+    char* char_two = vec_two.data();
+
+    // Create UTF16 representations
+    android::String16 str_one_utf16 = android::String16(char_one);
+    android::String16 str_two_utf16 = android::String16(char_two);
+
+    // Run operations against strings
+    int opsRun = 0;
+    while (dataProvider.remaining_bytes() > 0 && opsRun++ < MAX_OPERATIONS) {
+        uint8_t op = dataProvider.ConsumeIntegralInRange<uint8_t>(0, operations.size() - 1);
+        callFunc(op, dataProvider, str_one_utf16, str_two_utf16);
+    }
+
+    str_one_utf16.remove(0, str_one_utf16.size());
+    str_two_utf16.remove(0, str_two_utf16.size());
+    return 0;
+}
diff --git a/libutils/String8_fuzz.cpp b/libutils/String8_fuzz.cpp
new file mode 100644
index 0000000..2adfe98
--- /dev/null
+++ b/libutils/String8_fuzz.cpp
@@ -0,0 +1,136 @@
+/*
+ * Copyright 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 <functional>
+#include <iostream>
+
+#include "fuzzer/FuzzedDataProvider.h"
+#include "utils/String8.h"
+
+static constexpr int MAX_STRING_BYTES = 256;
+static constexpr uint8_t MAX_OPERATIONS = 50;
+
+std::vector<std::function<void(FuzzedDataProvider&, android::String8, android::String8)>>
+        operations = {
+
+                // Bytes and size
+                [](FuzzedDataProvider&, android::String8 str1, android::String8) -> void {
+                    str1.bytes();
+                },
+                [](FuzzedDataProvider&, android::String8 str1, android::String8) -> void {
+                    str1.isEmpty();
+                },
+                [](FuzzedDataProvider&, android::String8 str1, android::String8) -> void {
+                    str1.length();
+                },
+                [](FuzzedDataProvider&, android::String8 str1, android::String8) -> void {
+                    str1.size();
+                },
+
+                // Casing
+                [](FuzzedDataProvider&, android::String8 str1, android::String8) -> void {
+                    str1.toUpper();
+                },
+                [](FuzzedDataProvider&, android::String8 str1, android::String8) -> void {
+                    str1.toLower();
+                },
+
+                [](FuzzedDataProvider&, android::String8 str1, android::String8 str2) -> void {
+                    str1.removeAll(str2.c_str());
+                },
+                [](FuzzedDataProvider&, android::String8 str1, android::String8 str2) -> void {
+                    str1.compare(str2);
+                },
+
+                // Append and format
+                [](FuzzedDataProvider&, android::String8 str1, android::String8 str2) -> void {
+                    str1.append(str2);
+                },
+                [](FuzzedDataProvider&, android::String8 str1, android::String8 str2) -> void {
+                    str1.appendFormat(str1.c_str(), str2.c_str());
+                },
+                [](FuzzedDataProvider&, android::String8 str1, android::String8 str2) -> void {
+                    str1.format(str1.c_str(), str2.c_str());
+                },
+
+                // Find operation
+                [](FuzzedDataProvider& dataProvider, android::String8 str1,
+                   android::String8) -> void {
+                    // We need to get a value from our fuzzer here.
+                    int start_index = dataProvider.ConsumeIntegralInRange<int>(0, str1.size());
+                    str1.find(str1.c_str(), start_index);
+                },
+
+                // Path handling
+                [](FuzzedDataProvider&, android::String8 str1, android::String8) -> void {
+                    str1.getBasePath();
+                },
+                [](FuzzedDataProvider&, android::String8 str1, android::String8) -> void {
+                    str1.getPathExtension();
+                },
+                [](FuzzedDataProvider&, android::String8 str1, android::String8) -> void {
+                    str1.getPathLeaf();
+                },
+                [](FuzzedDataProvider&, android::String8 str1, android::String8) -> void {
+                    str1.getPathDir();
+                },
+                [](FuzzedDataProvider&, android::String8 str1, android::String8) -> void {
+                    str1.convertToResPath();
+                },
+                [](FuzzedDataProvider&, android::String8 str1, android::String8) -> void {
+                    android::String8 path_out_str = android::String8();
+                    str1.walkPath(&path_out_str);
+                    path_out_str.clear();
+                },
+                [](FuzzedDataProvider& dataProvider, android::String8 str1,
+                   android::String8) -> void {
+                    str1.setPathName(dataProvider.ConsumeBytesWithTerminator<char>(5).data());
+                },
+                [](FuzzedDataProvider& dataProvider, android::String8 str1,
+                   android::String8) -> void {
+                    str1.appendPath(dataProvider.ConsumeBytesWithTerminator<char>(5).data());
+                },
+};
+
+void callFunc(uint8_t index, FuzzedDataProvider& dataProvider, android::String8 str1,
+              android::String8 str2) {
+    operations[index](dataProvider, str1, str2);
+}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+    FuzzedDataProvider dataProvider(data, size);
+    // Generate vector lengths
+    const size_t kVecOneLen = dataProvider.ConsumeIntegralInRange<size_t>(1, MAX_STRING_BYTES);
+    const size_t kVecTwoLen = dataProvider.ConsumeIntegralInRange<size_t>(1, MAX_STRING_BYTES);
+    // Populate vectors
+    std::vector<char> vec = dataProvider.ConsumeBytesWithTerminator<char>(kVecOneLen);
+    std::vector<char> vec_two = dataProvider.ConsumeBytesWithTerminator<char>(kVecTwoLen);
+    // Create UTF-8 pointers
+    android::String8 str_one_utf8 = android::String8(vec.data());
+    android::String8 str_two_utf8 = android::String8(vec_two.data());
+
+    // Run operations against strings
+    int opsRun = 0;
+    while (dataProvider.remaining_bytes() > 0 && opsRun++ < MAX_OPERATIONS) {
+        uint8_t op = dataProvider.ConsumeIntegralInRange<uint8_t>(0, operations.size() - 1);
+        callFunc(op, dataProvider, str_one_utf8, str_two_utf8);
+    }
+
+    // Just to be extra sure these can be freed, we're going to explicitly clear
+    // them
+    str_one_utf8.clear();
+    str_two_utf8.clear();
+    return 0;
+}
diff --git a/libutils/Vector_fuzz.cpp b/libutils/Vector_fuzz.cpp
new file mode 100644
index 0000000..f6df051
--- /dev/null
+++ b/libutils/Vector_fuzz.cpp
@@ -0,0 +1,83 @@
+/*
+ * Copyright 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 "fuzzer/FuzzedDataProvider.h"
+#include "utils/Vector.h"
+static constexpr uint16_t MAX_VEC_SIZE = 5000;
+
+void runVectorFuzz(const uint8_t* data, size_t size) {
+    FuzzedDataProvider dataProvider(data, size);
+    android::Vector<uint8_t> vec = android::Vector<uint8_t>();
+    // We want to test handling of sizeof as well.
+    android::Vector<uint32_t> vec32 = android::Vector<uint32_t>();
+
+    // We're going to generate two vectors of this size
+    size_t vectorSize = dataProvider.ConsumeIntegralInRange<size_t>(0, MAX_VEC_SIZE);
+    vec.setCapacity(vectorSize);
+    vec32.setCapacity(vectorSize);
+    for (size_t i = 0; i < vectorSize; i++) {
+        uint8_t count = dataProvider.ConsumeIntegralInRange<uint8_t>(1, 5);
+        vec.insertAt((uint8_t)i, i, count);
+        vec32.insertAt((uint32_t)i, i, count);
+        vec.push_front(i);
+        vec32.push(i);
+    }
+
+    // Now we'll perform some test operations with any remaining data
+    // Index to perform operations at
+    size_t index = dataProvider.ConsumeIntegralInRange<size_t>(0, vec.size());
+    std::vector<uint8_t> remainingVec = dataProvider.ConsumeRemainingBytes<uint8_t>();
+    // Insert an array and vector
+    vec.insertArrayAt(remainingVec.data(), index, remainingVec.size());
+    android::Vector<uint8_t> vecCopy = android::Vector<uint8_t>(vec);
+    vec.insertVectorAt(vecCopy, index);
+    // Same thing for 32 bit vector
+    android::Vector<uint32_t> vec32Copy = android::Vector<uint32_t>(vec32);
+    vec32.insertArrayAt(vec32Copy.array(), index, vec32.size());
+    vec32.insertVectorAt(vec32Copy, index);
+    // Replace single character
+    if (remainingVec.size() > 0) {
+        vec.replaceAt(remainingVec[0], index);
+        vec32.replaceAt(static_cast<uint32_t>(remainingVec[0]), index);
+    } else {
+        vec.replaceAt(0, index);
+        vec32.replaceAt(0, index);
+    }
+    // Add any remaining bytes
+    for (uint8_t i : remainingVec) {
+        vec.add(i);
+        vec32.add(static_cast<uint32_t>(i));
+    }
+    // Shrink capactiy
+    vec.setCapacity(remainingVec.size());
+    vec32.setCapacity(remainingVec.size());
+    // Iterate through each pointer
+    size_t sum = 0;
+    for (auto& it : vec) {
+        sum += it;
+    }
+    for (auto& it : vec32) {
+        sum += it;
+    }
+    // Cleanup
+    vec.clear();
+    vecCopy.clear();
+    vec32.clear();
+    vec32Copy.clear();
+}
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+    runVectorFuzz(data, size);
+    return 0;
+}