src/bringup/bin/console-launcher/virtcon-setup.cc

// Copyright 2020 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "src/bringup/bin/console-launcher/virtcon-setup.h"

#include <lib/fdio/directory.h>
#include <lib/fdio/io.h>
#include <lib/fdio/spawn.h>
#include <lib/zircon-internal/paths.h>
#include <zircon/processargs.h>

namespace console_launcher {

namespace {

// Start a shell with a given command.
// If `cmd` is null, then the shell is launched interactively.
zx::status<zx::channel> StartShell(const char* cmd) {
  zx::channel local, remote;
  zx_status_t status = zx::channel::create(0, &local, &remote);
  if (status != ZX_OK) {
    return zx::error(status);
  }

  const char* argv[] = {ZX_SHELL_DEFAULT, nullptr, nullptr, nullptr};

  if (cmd) {
    argv[1] = "-c";
    argv[2] = cmd;
  }

  fdio_spawn_action_t actions[2] = {
      {.action = FDIO_SPAWN_ACTION_SET_NAME, .name = {.data = "vc:sh"}},
      {.action = FDIO_SPAWN_ACTION_ADD_HANDLE,
       .h = {.id = PA_HND(PA_FD, FDIO_FLAG_USE_FOR_STDIO), .handle = remote.release()}},
  };

  uint32_t flags = FDIO_SPAWN_CLONE_ALL & ~FDIO_SPAWN_CLONE_STDIO;

  char err_msg[FDIO_SPAWN_ERR_MSG_MAX_LENGTH];
  status = fdio_spawn_etc(ZX_HANDLE_INVALID, flags, argv[0], argv, nullptr, std::size(actions),
                          actions, nullptr, err_msg);
  if (status != ZX_OK) {
    printf("console-launcher: cannot spawn shell: %s: %d (%s)\n", err_msg, status,
           zx_status_get_string(status));
    return zx::error(status);
  }

  return zx::ok(std::move(local));
}

// Start a shell with a given command, and send it to virtcon.
// If `cmd` is null, then the shell is launched interactively.
zx_status_t StartVirtconShell(fidl::WireSyncClient<fuchsia_virtualconsole::SessionManager>& virtcon,
                              const char* cmd) {
  auto result = StartShell(cmd);
  if (!result.is_ok()) {
    fprintf(stderr, "console-launcher: unable start virtcon shell: %s\n", result.status_string());
    return result.status_value();
  }

  auto virtcon_result = virtcon.CreateSession(std::move(result.value()));
  if (!virtcon_result.ok()) {
    fprintf(stderr, "console-launcher: unable to create virtcon session: %d\n",
            virtcon_result.status());
    return virtcon_result.status();
  }
  if (virtcon_result->status != ZX_OK) {
    fprintf(stderr, "console-launcher: unable to create virtcon session: %d\n",
            virtcon_result->status);
    return virtcon_result->status;
  }
  return ZX_OK;
}

}  // namespace

zx::status<VirtconArgs> GetVirtconArgs(fidl::WireSyncClient<fuchsia_boot::Arguments>* boot_args) {
  fuchsia_boot::wire::BoolPair bool_keys[]{
      {fidl::StringView{"netsvc.disable"}, true},
      {fidl::StringView{"netsvc.netboot"}, false},
      {fidl::StringView{"devmgr.require-system"}, false},
  };
  auto bool_resp =
      boot_args->GetBools(fidl::VectorView<fuchsia_boot::wire::BoolPair>::FromExternal(bool_keys));
  if (!bool_resp.ok()) {
    return zx::error(bool_resp.status());
  }

  const bool netsvc_disable = bool_resp->values[0];
  const bool netsvc_netboot = bool_resp->values[1];
  const bool require_system = bool_resp->values[2];

  const bool netboot = !netsvc_disable && netsvc_netboot;
  const bool should_launch = !require_system || netboot;

  VirtconArgs args;
  args.should_launch = should_launch;
  args.need_debuglog = netboot;

  return zx::ok(std::move(args));
}

zx_status_t SetupVirtconEtc(fidl::WireSyncClient<fuchsia_virtualconsole::SessionManager>& virtcon,
                            const VirtconArgs& args) {
  if (!args.should_launch) {
    return ZX_OK;
  }

  constexpr size_t kNumShells = 3;
  for (size_t i = 0; i < kNumShells; i++) {
    zx_status_t status;
    if (args.need_debuglog && (i == 0)) {
      status = StartVirtconShell(virtcon, "dlog -f -t");
    } else {
      status = StartVirtconShell(virtcon, nullptr);
    }
    if (status != ZX_OK) {
      return status;
    }
  }

  return ZX_OK;
}

zx_status_t SetupVirtcon(fidl::WireSyncClient<fuchsia_boot::Arguments>* boot_args) {
  auto result = GetVirtconArgs(boot_args);
  if (!result.is_ok()) {
    return result.status_value();
  }
  VirtconArgs args = std::move(result.value());

  if (!args.should_launch) {
    return ZX_OK;
  }

  fidl::WireSyncClient<fuchsia_virtualconsole::SessionManager> virtcon;
  {
    zx::channel local, remote;
    zx_status_t status = zx::channel::create(0, &local, &remote);
    if (status != ZX_OK) {
      return status;
    }

    status = fdio_service_connect("/svc/fuchsia.virtualconsole.SessionManager", remote.release());
    if (status != ZX_OK) {
      fprintf(stderr, "console-launcher: unable to connect to %s: %d\n",
              fidl::DiscoverableProtocolName<fuchsia_virtualconsole::SessionManager>, status);
      return status;
    }
    virtcon = fidl::WireSyncClient<fuchsia_virtualconsole::SessionManager>(std::move(local));
  }

  return SetupVirtconEtc(virtcon, args);
}

}  // namespace console_launcher