Add socket communication between recovery and minadbd

This cl adds a socket pair to support the communication between recovery
and minadbd. Therefore, minadbd will be able to issue multiple commands
to recovery and get back the status of each command.

This cl also switches the adb sideload from the recovery menu to use
this protocol; and moves minadbd to a separate binary.

Bug: 130166585
Test: sideload a package
Change-Id: I80d36d5c4e6fe1ae3ea23640907bc50c0dc0d482
diff --git a/Android.bp b/Android.bp
index 137004c..582f3b6 100644
--- a/Android.bp
+++ b/Android.bp
@@ -112,7 +112,6 @@
     ],
 
     shared_libs: [
-        "libminadbd_services",
         "librecovery_ui",
     ],
 
@@ -124,6 +123,7 @@
     required: [
         "e2fsdroid.recovery",
         "librecovery_ui_ext",
+        "minadbd",
         "mke2fs.conf.recovery",
         "mke2fs.recovery",
         "recovery_deps",
diff --git a/install/Android.bp b/install/Android.bp
index 85cf9ac..2ffc442 100644
--- a/install/Android.bp
+++ b/install/Android.bp
@@ -19,6 +19,10 @@
         "recovery_defaults",
     ],
 
+    header_libs: [
+        "libminadbd_headers",
+    ],
+
     shared_libs: [
         "libbase",
         "libbootloader_message",
diff --git a/install/adb_install.cpp b/install/adb_install.cpp
index 5296ff6..dc7ee0b 100644
--- a/install/adb_install.cpp
+++ b/install/adb_install.cpp
@@ -21,23 +21,265 @@
 #include <signal.h>
 #include <stdlib.h>
 #include <string.h>
+#include <sys/epoll.h>
+#include <sys/socket.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <unistd.h>
 
+#include <atomic>
+#include <functional>
+#include <map>
+
+#include <android-base/file.h>
 #include <android-base/logging.h>
+#include <android-base/memory.h>
 #include <android-base/properties.h>
+#include <android-base/strings.h>
+#include <android-base/unique_fd.h>
 
 #include "fuse_sideload.h"
 #include "install/install.h"
+#include "minadbd_types.h"
 #include "recovery_ui/ui.h"
 
+using CommandFunction = std::function<bool()>;
+
 static bool SetUsbConfig(const std::string& state) {
   android::base::SetProperty("sys.usb.config", state);
   return android::base::WaitForProperty("sys.usb.state", state);
 }
 
+// Parses the minadbd command in |message|; returns MinadbdCommands::kError upon errors.
+static MinadbdCommands ParseMinadbdCommands(const std::string& message) {
+  if (!android::base::StartsWith(message, kMinadbdCommandPrefix)) {
+    LOG(ERROR) << "Failed to parse command in message " << message;
+    return MinadbdCommands::kError;
+  }
+
+  auto cmd_code_string = message.substr(strlen(kMinadbdCommandPrefix));
+  auto cmd_code = android::base::get_unaligned<uint32_t>(cmd_code_string.c_str());
+  if (cmd_code >= static_cast<uint32_t>(MinadbdCommands::kError)) {
+    LOG(ERROR) << "Unsupported command code: " << cmd_code;
+    return MinadbdCommands::kError;
+  }
+
+  return static_cast<MinadbdCommands>(cmd_code);
+}
+
+static bool WriteStatusToFd(MinadbdCommandStatus status, int fd) {
+  char message[kMinadbdMessageSize];
+  memcpy(message, kMinadbdStatusPrefix, strlen(kMinadbdStatusPrefix));
+  android::base::put_unaligned(message + strlen(kMinadbdStatusPrefix), status);
+
+  if (!android::base::WriteFully(fd, message, kMinadbdMessageSize)) {
+    PLOG(ERROR) << "Failed to write message " << message;
+    return false;
+  }
+  return true;
+}
+
+// Installs the package from FUSE. Returns true if the installation succeeds, and false otherwise.
+static bool AdbInstallPackageHandler(bool* wipe_cache, RecoveryUI* ui, int* result) {
+  // How long (in seconds) we wait for the package path to be ready. It doesn't need to be too long
+  // because the minadbd service has already issued an install command. FUSE_SIDELOAD_HOST_PATHNAME
+  // will start to exist once the host connects and starts serving a package. Poll for its
+  // appearance. (Note that inotify doesn't work with FUSE.)
+  constexpr int ADB_INSTALL_TIMEOUT = 15;
+  *result = INSTALL_ERROR;
+  for (int i = 0; i < ADB_INSTALL_TIMEOUT; ++i) {
+    struct stat st;
+    if (stat(FUSE_SIDELOAD_HOST_PATHNAME, &st) != 0) {
+      if (errno == ENOENT && i < ADB_INSTALL_TIMEOUT - 1) {
+        sleep(1);
+        continue;
+      } else {
+        ui->Print("\nTimed out waiting for fuse to be ready.\n\n");
+        break;
+      }
+    }
+    *result = install_package(FUSE_SIDELOAD_HOST_PATHNAME, wipe_cache, false, 0, ui);
+    break;
+  }
+
+  // Calling stat() on this magic filename signals the FUSE to exit.
+  struct stat st;
+  stat(FUSE_SIDELOAD_HOST_EXIT_PATHNAME, &st);
+  return *result == INSTALL_SUCCESS;
+}
+
+// Parses and executes the command from minadbd. Returns false if we enter an invalid state so that
+// the caller can kill the minadbd service properly.
+static bool HandleMessageFromMinadbd(
+    int socket_fd, const std::map<MinadbdCommands, CommandFunction>& command_map) {
+  char buffer[kMinadbdMessageSize];
+  if (!android::base::ReadFully(socket_fd, buffer, kMinadbdMessageSize)) {
+    PLOG(ERROR) << "Failed to read message from minadbd";
+    return false;
+  }
+
+  std::string message(buffer, buffer + kMinadbdMessageSize);
+  auto command_type = ParseMinadbdCommands(message);
+  if (command_type == MinadbdCommands::kError) {
+    return false;
+  }
+  if (command_map.find(command_type) == command_map.end()) {
+    LOG(ERROR) << "Unsupported command: "
+               << android::base::get_unaligned<unsigned int>(
+                      message.substr(strlen(kMinadbdCommandPrefix)).c_str());
+    return false;
+  }
+
+  // We have received a valid command, execute the corresponding function.
+  const auto& command_func = command_map.at(command_type);
+  if (!command_func()) {
+    LOG(ERROR) << "Failed to execute command " << static_cast<unsigned int>(command_type);
+    return WriteStatusToFd(MinadbdCommandStatus::kFailure, socket_fd);
+  }
+  return WriteStatusToFd(MinadbdCommandStatus::kSuccess, socket_fd);
+}
+
+// TODO(xunchang) add a wrapper function and kill the minadbd service there.
+static void ListenAndExecuteMinadbdCommands(
+    pid_t minadbd_pid, android::base::unique_fd&& socket_fd,
+    const std::map<MinadbdCommands, CommandFunction>& command_map) {
+  android::base::unique_fd epoll_fd(epoll_create1(O_CLOEXEC));
+  if (epoll_fd == -1) {
+    PLOG(ERROR) << "Failed to create epoll";
+    kill(minadbd_pid, SIGKILL);
+    return;
+  }
+
+  constexpr int EPOLL_MAX_EVENTS = 10;
+  struct epoll_event ev = {};
+  ev.events = EPOLLIN | EPOLLHUP;
+  ev.data.fd = socket_fd.get();
+  struct epoll_event events[EPOLL_MAX_EVENTS];
+  if (epoll_ctl(epoll_fd.get(), EPOLL_CTL_ADD, socket_fd.get(), &ev) == -1) {
+    PLOG(ERROR) << "Failed to add socket fd to epoll";
+    kill(minadbd_pid, SIGKILL);
+    return;
+  }
+
+  // Set the timeout to be 300s when waiting for minadbd commands.
+  constexpr int TIMEOUT_MILLIS = 300 * 1000;
+  while (true) {
+    // Poll for the status change of the socket_fd, and handle the message if the fd is ready to
+    // read.
+    int event_count =
+        TEMP_FAILURE_RETRY(epoll_wait(epoll_fd.get(), events, EPOLL_MAX_EVENTS, TIMEOUT_MILLIS));
+    if (event_count == -1) {
+      PLOG(ERROR) << "Failed to wait for epoll events";
+      kill(minadbd_pid, SIGKILL);
+      return;
+    }
+    if (event_count == 0) {
+      LOG(ERROR) << "Timeout waiting for messages from minadbd";
+      kill(minadbd_pid, SIGKILL);
+      return;
+    }
+
+    for (int n = 0; n < event_count; n++) {
+      if (events[n].events & EPOLLHUP) {
+        LOG(INFO) << "Socket has been closed";
+        kill(minadbd_pid, SIGKILL);
+        return;
+      }
+      if (!HandleMessageFromMinadbd(socket_fd.get(), command_map)) {
+        kill(minadbd_pid, SIGKILL);
+        return;
+      }
+    }
+  }
+}
+
+// Recovery starts minadbd service as a child process, and spawns another thread to listen for the
+// message from minadbd through a socket pair. Here is an example to execute one command from adb
+// host.
+//  a. recovery                    b. listener thread               c. minadbd service
+//
+//  a1. create socket pair
+//  a2. fork minadbd service
+//                                                                c3. wait for the adb commands
+//                                                                    from host
+//                                                                c4. after receiving host commands:
+//                                                                  1) set up pre-condition (i.e.
+//                                                                     start fuse for adb sideload)
+//                                                                  2) issue command through
+//                                                                     socket.
+//                                                                  3) wait for result
+//  a5. start listener thread
+//                               b6. listen for message from
+//                                   minadbd in a loop.
+//                               b7. After receiving a minadbd
+//                                   command from socket
+//                                 1) execute the command function
+//                                 2) send the result back to
+//                                    minadbd
+//  ......
+//                                                                 c8. exit upon receiving the
+//                                                                     result
+// a9.  wait for listener thread
+//      to exit.
+//
+// a10. wait for minadbd to
+//      exit
+//                               b11. exit the listening loop
+//
+static void CreateMinadbdServiceAndExecuteCommands(
+    const std::map<MinadbdCommands, CommandFunction>& command_map) {
+  signal(SIGPIPE, SIG_IGN);
+
+  android::base::unique_fd recovery_socket;
+  android::base::unique_fd minadbd_socket;
+  if (!android::base::Socketpair(AF_UNIX, SOCK_STREAM, 0, &recovery_socket, &minadbd_socket)) {
+    PLOG(ERROR) << "Failed to create socket";
+    return;
+  }
+
+  pid_t child = fork();
+  if (child == -1) {
+    PLOG(ERROR) << "Failed to fork child process";
+    return;
+  }
+  if (child == 0) {
+    recovery_socket.reset();
+    execl("/system/bin/minadbd", "minadbd", "--socket_fd",
+          std::to_string(minadbd_socket.release()).c_str(), nullptr);
+
+    _exit(EXIT_FAILURE);
+  }
+
+  minadbd_socket.reset();
+
+  // We need to call SetUsbConfig() after forking minadbd service. Because the function waits for
+  // the usb state to be updated, which depends on sys.usb.ffs.ready=1 set in the adb daemon.
+  if (!SetUsbConfig("sideload")) {
+    LOG(ERROR) << "Failed to set usb config to sideload";
+    return;
+  }
+
+  std::thread listener_thread(ListenAndExecuteMinadbdCommands, child, std::move(recovery_socket),
+                              std::ref(command_map));
+
+  if (listener_thread.joinable()) {
+    listener_thread.join();
+  }
+
+  int status;
+  waitpid(child, &status, 0);
+  if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
+    if (WEXITSTATUS(status) == MinadbdErrorCode::kMinadbdAdbVersionError) {
+      LOG(ERROR) << "\nYou need adb 1.0.32 or newer to sideload\nto this device.\n";
+    } else if (!WIFSIGNALED(status)) {
+      LOG(ERROR) << "\n(adbd status " << WEXITSTATUS(status) << ")";
+    }
+  }
+
+  signal(SIGPIPE, SIG_DFL);
+}
+
 int apply_from_adb(bool* wipe_cache, RecoveryUI* ui) {
   // Save the usb state to restore after the sideload operation.
   std::string usb_state = android::base::GetProperty("sys.usb.state", "none");
@@ -51,66 +293,13 @@
       "\n\nNow send the package you want to apply\n"
       "to the device with \"adb sideload <filename>\"...\n");
 
-  pid_t child;
-  if ((child = fork()) == 0) {
-    execl("/system/bin/recovery", "recovery", "--adbd", nullptr);
-    _exit(EXIT_FAILURE);
-  }
+  int install_result = INSTALL_ERROR;
+  std::map<MinadbdCommands, CommandFunction> command_map{
+    { MinadbdCommands::kInstall,
+      std::bind(&AdbInstallPackageHandler, wipe_cache, ui, &install_result) },
+  };
 
-  if (!SetUsbConfig("sideload")) {
-    LOG(ERROR) << "Failed to set usb config to sideload";
-    return INSTALL_ERROR;
-  }
-
-  // How long (in seconds) we wait for the host to start sending us a package, before timing out.
-  static constexpr int ADB_INSTALL_TIMEOUT = 300;
-
-  // FUSE_SIDELOAD_HOST_PATHNAME will start to exist once the host connects and starts serving a
-  // package. Poll for its appearance. (Note that inotify doesn't work with FUSE.)
-  int result = INSTALL_ERROR;
-  int status;
-  bool waited = false;
-  for (int i = 0; i < ADB_INSTALL_TIMEOUT; ++i) {
-    if (waitpid(child, &status, WNOHANG) != 0) {
-      result = INSTALL_ERROR;
-      waited = true;
-      break;
-    }
-
-    struct stat st;
-    if (stat(FUSE_SIDELOAD_HOST_PATHNAME, &st) != 0) {
-      if (errno == ENOENT && i < ADB_INSTALL_TIMEOUT - 1) {
-        sleep(1);
-        continue;
-      } else {
-        ui->Print("\nTimed out waiting for package.\n\n");
-        result = INSTALL_ERROR;
-        kill(child, SIGKILL);
-        break;
-      }
-    }
-    result = install_package(FUSE_SIDELOAD_HOST_PATHNAME, wipe_cache, false, 0, ui);
-    break;
-  }
-
-  if (!waited) {
-    // Calling stat() on this magic filename signals the minadbd subprocess to shut down.
-    struct stat st;
-    stat(FUSE_SIDELOAD_HOST_EXIT_PATHNAME, &st);
-
-    // TODO: there should be a way to cancel waiting for a package (by pushing some button combo on
-    // the device). For now you just have to 'adb sideload' a file that's not a valid package, like
-    // "/dev/null".
-    waitpid(child, &status, 0);
-  }
-
-  if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
-    if (WEXITSTATUS(status) == 3) {
-      ui->Print("\nYou need adb 1.0.32 or newer to sideload\nto this device.\n\n");
-    } else if (!WIFSIGNALED(status)) {
-      ui->Print("\n(adbd status %d)\n", WEXITSTATUS(status));
-    }
-  }
+  CreateMinadbdServiceAndExecuteCommands(command_map);
 
   // Clean up before switching to the older state, for example setting the state
   // to none sets sys/class/android_usb/android0/enable to 0.
@@ -124,5 +313,5 @@
     }
   }
 
-  return result;
+  return install_result;
 }
diff --git a/minadbd/Android.bp b/minadbd/Android.bp
index 9b889f4..e4f7712 100644
--- a/minadbd/Android.bp
+++ b/minadbd/Android.bp
@@ -40,7 +40,6 @@
 
     srcs: [
         "fuse_adb_provider.cpp",
-        "minadbd.cpp",
         "minadbd_services.cpp",
     ],
 
@@ -52,6 +51,36 @@
     ],
 }
 
+cc_library_headers {
+    name: "libminadbd_headers",
+    recovery_available: true,
+    // TODO create a include dir
+    export_include_dirs: [
+        ".",
+    ],
+}
+
+cc_binary {
+    name: "minadbd",
+    recovery: true,
+
+    defaults: [
+        "minadbd_defaults",
+    ],
+
+    srcs: [
+        "minadbd.cpp",
+    ],
+
+    shared_libs: [
+        "libadbd",
+        "libbase",
+        "libcrypto",
+        "libfusesideload",
+        "libminadbd_services",
+    ],
+}
+
 cc_test {
     name: "minadbd_test",
     isolated: true,
diff --git a/minadbd/minadbd.cpp b/minadbd/minadbd.cpp
index 349189c..57158ad 100644
--- a/minadbd/minadbd.cpp
+++ b/minadbd/minadbd.cpp
@@ -14,30 +14,54 @@
  * limitations under the License.
  */
 
-#include "minadbd.h"
-
 #include <errno.h>
+#include <fcntl.h>
 #include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <strings.h>
+
+#include <android-base/logging.h>
+#include <android-base/parseint.h>
 
 #include "adb.h"
 #include "adb_auth.h"
 #include "transport.h"
 
-int minadbd_main() {
-    adb_device_banner = "sideload";
+#include "minadbd_services.h"
+#include "minadbd_types.h"
 
-    signal(SIGPIPE, SIG_IGN);
+int main(int argc, char** argv) {
+  android::base::InitLogging(argv, &android::base::StderrLogger);
+  // TODO(xunchang) implement a command parser
+  if (argc != 3 || strcmp("--socket_fd", argv[1]) != 0) {
+    LOG(ERROR) << "minadbd has invalid arguments, argc: " << argc;
+    exit(kMinadbdArgumentsParsingError);
+  }
 
-    // We can't require authentication for sideloading. http://b/22025550.
-    auth_required = false;
+  int socket_fd;
+  if (!android::base::ParseInt(argv[2], &socket_fd)) {
+    LOG(ERROR) << "Failed to parse int in " << argv[2];
+    exit(kMinadbdArgumentsParsingError);
+  }
+  if (fcntl(socket_fd, F_GETFD, 0) == -1) {
+    PLOG(ERROR) << "Failed to get minadbd socket";
+    exit(kMinadbdSocketIOError);
+  }
+  SetMinadbdSocketFd(socket_fd);
 
-    init_transport_registration();
-    usb_init();
+  adb_device_banner = "sideload";
 
-    VLOG(ADB) << "Event loop starting";
-    fdevent_loop();
+  signal(SIGPIPE, SIG_IGN);
 
-    return 0;
+  // We can't require authentication for sideloading. http://b/22025550.
+  auth_required = false;
+
+  init_transport_registration();
+  usb_init();
+
+  VLOG(ADB) << "Event loop starting";
+  fdevent_loop();
+
+  return 0;
 }
diff --git a/minadbd/minadbd_services.cpp b/minadbd/minadbd_services.cpp
index 6fe5c79..79e6fc4 100644
--- a/minadbd/minadbd_services.cpp
+++ b/minadbd/minadbd_services.cpp
@@ -14,6 +14,8 @@
  * limitations under the License.
  */
 
+#include "minadbd_services.h"
+
 #include <errno.h>
 #include <inttypes.h>
 #include <stdio.h>
@@ -27,38 +29,95 @@
 #include <string_view>
 #include <thread>
 
+#include <android-base/file.h>
+#include <android-base/logging.h>
+#include <android-base/memory.h>
+#include <android-base/stringprintf.h>
+#include <android-base/strings.h>
+
 #include "adb.h"
 #include "adb_unique_fd.h"
 #include "fdevent.h"
 #include "fuse_adb_provider.h"
 #include "fuse_sideload.h"
+#include "minadbd_types.h"
 #include "services.h"
 #include "sysdeps.h"
 
+static int minadbd_socket = -1;
+void SetMinadbdSocketFd(int socket_fd) {
+  minadbd_socket = socket_fd;
+}
+
+static bool WriteCommandToFd(MinadbdCommands cmd, int fd) {
+  char message[kMinadbdMessageSize];
+  memcpy(message, kMinadbdCommandPrefix, strlen(kMinadbdStatusPrefix));
+  android::base::put_unaligned(message + strlen(kMinadbdStatusPrefix), cmd);
+
+  if (!android::base::WriteFully(fd, message, kMinadbdMessageSize)) {
+    PLOG(ERROR) << "Failed to write message " << message;
+    return false;
+  }
+  return true;
+}
+
+// Blocks and reads the command status from |fd|. Returns false if the received message has a
+// format error.
+static bool WaitForCommandStatus(int fd, MinadbdCommandStatus* status) {
+  char buffer[kMinadbdMessageSize];
+  if (!android::base::ReadFully(fd, buffer, kMinadbdMessageSize)) {
+    PLOG(ERROR) << "Failed to response status from socket";
+    exit(kMinadbdSocketIOError);
+  }
+
+  std::string message(buffer, buffer + kMinadbdMessageSize);
+  if (!android::base::StartsWith(message, kMinadbdStatusPrefix)) {
+    LOG(ERROR) << "Failed to parse status in " << message;
+    return false;
+  }
+
+  *status = android::base::get_unaligned<MinadbdCommandStatus>(
+      message.substr(strlen(kMinadbdStatusPrefix)).c_str());
+  return true;
+}
+
 static void sideload_host_service(unique_fd sfd, const std::string& args) {
   int64_t file_size;
   int block_size;
   if ((sscanf(args.c_str(), "%" SCNd64 ":%d", &file_size, &block_size) != 2) || file_size <= 0 ||
       block_size <= 0) {
-    printf("bad sideload-host arguments: %s\n", args.c_str());
-    exit(1);
+    LOG(ERROR) << "bad sideload-host arguments: " << args;
+    exit(kMinadbdPackageSizeError);
   }
 
-  printf("sideload-host file size %" PRId64 " block size %d\n", file_size, block_size);
+  LOG(INFO) << "sideload-host file size " << file_size << ", block size " << block_size;
+
+  if (!WriteCommandToFd(MinadbdCommands::kInstall, minadbd_socket)) {
+    exit(kMinadbdSocketIOError);
+  }
 
   auto adb_data_reader =
       std::make_unique<FuseAdbDataProvider>(std::move(sfd), file_size, block_size);
-  int result = run_fuse_sideload(std::move(adb_data_reader));
+  if (int result = run_fuse_sideload(std::move(adb_data_reader)); result != 0) {
+    LOG(ERROR) << "Failed to start fuse";
+    exit(kMinadbdFuseStartError);
+  }
 
-  printf("sideload_host finished\n");
-  exit(result == 0 ? 0 : 1);
+  MinadbdCommandStatus status;
+  if (!WaitForCommandStatus(minadbd_socket, &status)) {
+    exit(kMinadbdMessageFormatError);
+  }
+  LOG(INFO) << "Got command status: " << static_cast<unsigned int>(status);
+
+  LOG(INFO) << "sideload_host finished";
+  exit(kMinadbdSuccess);
 }
 
 unique_fd daemon_service_to_fd(std::string_view name, atransport* /* transport */) {
   if (name.starts_with("sideload:")) {
     // This exit status causes recovery to print a special error message saying to use a newer adb
     // (that supports sideload-host).
-    exit(3);
+    exit(kMinadbdAdbVersionError);
   } else if (name.starts_with("sideload-host:")) {
     std::string arg(name.substr(strlen("sideload-host:")));
     return create_service_thread("sideload-host",
diff --git a/minadbd/minadbd.h b/minadbd/minadbd_services.h
similarity index 89%
rename from minadbd/minadbd.h
rename to minadbd/minadbd_services.h
index 3570a5d..6835bd7 100644
--- a/minadbd/minadbd.h
+++ b/minadbd/minadbd_services.h
@@ -14,9 +14,6 @@
  * limitations under the License.
  */
 
-#ifndef MINADBD_H__
-#define MINADBD_H__
+#pragma once
 
-int minadbd_main();
-
-#endif
+void SetMinadbdSocketFd(int socket_fd);
diff --git a/minadbd/minadbd_types.h b/minadbd/minadbd_types.h
new file mode 100644
index 0000000..7bd6909
--- /dev/null
+++ b/minadbd/minadbd_types.h
@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2019 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 <stdint.h>
+
+// The message between recovery and minadbd is 8 bytes in size unless the length is explicitly
+// specified. Both the command and status has the format |prefix(4 bytes) + encoded enum(4 bytes)|.
+constexpr size_t kMinadbdMessageSize = 8;
+constexpr char const kMinadbdCommandPrefix[] = "COMD";
+constexpr char const kMinadbdStatusPrefix[] = "STAT";
+
+enum MinadbdErrorCode : int {
+  kMinadbdSuccess = 0,
+  kMinadbdArgumentsParsingError = 1,
+  kMinadbdSocketIOError = 2,
+  kMinadbdMessageFormatError = 3,
+  kMinadbdAdbVersionError = 4,
+  kMinadbdPackageSizeError = 5,
+  kMinadbdFuseStartError = 6,
+  kMinadbdUnsupportedCommandError = 7,
+  kMinadbdCommandExecutionError = 8,
+  kMinadbdErrorUnknown = 9,
+};
+
+enum class MinadbdCommandStatus : uint32_t {
+  kSuccess = 0,
+  kFailure = 1,
+};
+
+enum class MinadbdCommands : uint32_t {
+  kInstall = 0,
+  kUiPrint = 1,
+  kError = 2,
+};
+
+static_assert(kMinadbdMessageSize == sizeof(kMinadbdCommandPrefix) - 1 + sizeof(MinadbdCommands));
+static_assert(kMinadbdMessageSize ==
+              sizeof(kMinadbdStatusPrefix) - 1 + sizeof(MinadbdCommandStatus));
diff --git a/recovery_main.cpp b/recovery_main.cpp
index b41368d..8b4ad5a 100644
--- a/recovery_main.cpp
+++ b/recovery_main.cpp
@@ -51,7 +51,6 @@
 #include "common.h"
 #include "fastboot/fastboot.h"
 #include "logging.h"
-#include "minadbd/minadbd.h"
 #include "otautil/paths.h"
 #include "otautil/roots.h"
 #include "otautil/sysutil.h"
@@ -322,16 +321,6 @@
   // Take action to refresh pmsg contents
   __android_log_pmsg_file_read(LOG_ID_SYSTEM, ANDROID_LOG_INFO, filter, logrotate, &do_rotate);
 
-  // If this binary is started with the single argument "--adbd", instead of being the normal
-  // recovery binary, it turns into kind of a stripped-down version of adbd that only supports the
-  // 'sideload' command.  Note this must be a real argument, not anything in the command file or
-  // bootloader control block; the only way recovery should be run with this argument is when it
-  // starts a copy of itself from the apply_from_adb() function.
-  if (argc == 2 && strcmp(argv[1], "--adbd") == 0) {
-    minadbd_main();
-    return 0;
-  }
-
   time_t start = time(nullptr);
 
   // redirect_stdio should be called only in non-sideload mode. Otherwise we may have two logger