Files
sdk/runtime/bin/vmservice_impl.cc
T
jonahwilliams 96ff3276f4 [vmservice] allow fallback on port bind failure
Work towards https://github.com/flutter/flutter/issues/46724

Background:

on the latest versions of iOS today, we have to use mdns to discover the observatory port and authentication code. For a variety of reasons this can fail, leaving us with no way to connect.

An alternative approach is to specify the observatory port and disable the authentication code. If binding to this port fails, however, we would still like to attempt connecting with mdns.

Overview:

This adds a new flag to the dart SDK, --enable-service-port-fallback. This amends the behavior of the vmservice with a specified port. After failing to bind 3 times to a non-zero port, update the port selection to 0.

Results:

Tested locally two dart VMs with the same specified port:

```
jonahwilliams@jonahwilliams0:~/Documents/engine/src/out/host_debug_unopt$ ./dart --enable-service-port-fallback --observe=8080 example.dart
Observatory server failed to start after 1 tries
Falling back to automatic port selection

vm-service: isolate(2785434094928835)  'main' has no debugger attached and is paused at exit.  Connect to Observatory to debug.
Observatory listening on http://127.0.0.1:45663/62A5IHjmv9E=/
```
Change-Id: I582ab402a457330928e5b490f9718fcd52b56720
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/133434
Reviewed-by: Ben Konyi <bkonyi@google.com>
Commit-Queue: Jonah Williams <jonahwilliams@google.com>
2020-01-28 23:36:14 +00:00

246 lines
8.3 KiB
C++

// Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
#include "bin/vmservice_impl.h"
#include "include/dart_api.h"
#include "bin/builtin.h"
#include "bin/dartutils.h"
#include "bin/isolate_data.h"
#include "bin/platform.h"
#include "bin/thread.h"
#include "bin/utils.h"
#include "platform/text_buffer.h"
namespace dart {
namespace bin {
#define RETURN_ERROR_HANDLE(handle) \
if (Dart_IsError(handle)) { \
return handle; \
}
#define SHUTDOWN_ON_ERROR(handle) \
if (Dart_IsError(handle)) { \
error_msg_ = strdup(Dart_GetError(handle)); \
Dart_ExitScope(); \
Dart_ShutdownIsolate(); \
return false; \
}
static const char* const kVMServiceIOLibraryUri = "dart:vmservice_io";
void NotifyServerState(Dart_NativeArguments args) {
Dart_EnterScope();
const char* uri_chars;
Dart_Handle uri_arg = Dart_GetNativeArgument(args, 0);
if (Dart_IsError(uri_arg)) {
VmService::SetServerAddress("");
Dart_ExitScope();
return;
}
Dart_Handle result = Dart_StringToCString(uri_arg, &uri_chars);
if (Dart_IsError(result)) {
VmService::SetServerAddress("");
Dart_ExitScope();
return;
}
VmService::SetServerAddress(uri_chars);
Dart_ExitScope();
}
static void Shutdown(Dart_NativeArguments args) {
// NO-OP.
}
struct VmServiceIONativeEntry {
const char* name;
int num_arguments;
Dart_NativeFunction function;
};
static VmServiceIONativeEntry _VmServiceIONativeEntries[] = {
{"VMServiceIO_NotifyServerState", 1, NotifyServerState},
{"VMServiceIO_Shutdown", 0, Shutdown},
};
static Dart_NativeFunction VmServiceIONativeResolver(Dart_Handle name,
int num_arguments,
bool* auto_setup_scope) {
const char* function_name = NULL;
Dart_Handle result = Dart_StringToCString(name, &function_name);
ASSERT(!Dart_IsError(result));
ASSERT(function_name != NULL);
*auto_setup_scope = true;
intptr_t n =
sizeof(_VmServiceIONativeEntries) / sizeof(_VmServiceIONativeEntries[0]);
for (intptr_t i = 0; i < n; i++) {
VmServiceIONativeEntry entry = _VmServiceIONativeEntries[i];
if ((strcmp(function_name, entry.name) == 0) &&
(num_arguments == entry.num_arguments)) {
return entry.function;
}
}
return NULL;
}
const uint8_t* VmServiceIONativeSymbol(Dart_NativeFunction nf) {
intptr_t n =
sizeof(_VmServiceIONativeEntries) / sizeof(_VmServiceIONativeEntries[0]);
for (intptr_t i = 0; i < n; i++) {
VmServiceIONativeEntry entry = _VmServiceIONativeEntries[i];
if (reinterpret_cast<Dart_NativeFunction>(entry.function) == nf) {
return reinterpret_cast<const uint8_t*>(entry.name);
}
}
return NULL;
}
const char* VmService::error_msg_ = NULL;
char VmService::server_uri_[kServerUriStringBufferSize];
void VmService::SetNativeResolver() {
Dart_Handle url = DartUtils::NewString(kVMServiceIOLibraryUri);
Dart_Handle library = Dart_LookupLibrary(url);
if (!Dart_IsError(library)) {
Dart_SetNativeResolver(library, VmServiceIONativeResolver,
VmServiceIONativeSymbol);
}
}
bool VmService::Setup(const char* server_ip,
intptr_t server_port,
bool dev_mode_server,
bool auth_codes_disabled,
const char* write_service_info_filename,
bool trace_loading,
bool deterministic,
bool enable_service_port_fallback) {
Dart_Isolate isolate = Dart_CurrentIsolate();
ASSERT(isolate != NULL);
SetServerAddress("");
Dart_Handle result;
// Prepare builtin and its dependent libraries for use to resolve URIs.
// Set up various closures, e.g: printing, timers etc.
// Set up 'package root' for URI resolution.
result = DartUtils::PrepareForScriptLoading(/*is_service_isolate=*/true,
trace_loading);
SHUTDOWN_ON_ERROR(result);
Dart_Handle url = DartUtils::NewString(kVMServiceIOLibraryUri);
Dart_Handle library = Dart_LookupLibrary(url);
SHUTDOWN_ON_ERROR(library);
result = Dart_SetRootLibrary(library);
SHUTDOWN_ON_ERROR(library);
result = Dart_SetNativeResolver(library, VmServiceIONativeResolver,
VmServiceIONativeSymbol);
SHUTDOWN_ON_ERROR(result);
// Make runnable.
Dart_ExitScope();
Dart_ExitIsolate();
error_msg_ = Dart_IsolateMakeRunnable(isolate);
if (error_msg_ != NULL) {
Dart_EnterIsolate(isolate);
Dart_ShutdownIsolate();
return false;
}
Dart_EnterIsolate(isolate);
Dart_EnterScope();
library = Dart_RootLibrary();
SHUTDOWN_ON_ERROR(library);
// Set HTTP server state.
result = DartUtils::SetStringField(library, "_ip", server_ip);
SHUTDOWN_ON_ERROR(result);
// If we have a port specified, start the server immediately.
bool auto_start = server_port >= 0;
if (server_port < 0) {
// Adjust server_port to port 0 which will result in the first available
// port when the HTTP server is started.
server_port = 0;
}
result = DartUtils::SetIntegerField(library, "_port", server_port);
SHUTDOWN_ON_ERROR(result);
result = Dart_SetField(library, DartUtils::NewString("_autoStart"),
Dart_NewBoolean(auto_start));
SHUTDOWN_ON_ERROR(result);
result = Dart_SetField(library, DartUtils::NewString("_originCheckDisabled"),
Dart_NewBoolean(dev_mode_server));
SHUTDOWN_ON_ERROR(result);
result = Dart_SetField(library, DartUtils::NewString("_authCodesDisabled"),
Dart_NewBoolean(auth_codes_disabled));
SHUTDOWN_ON_ERROR(result);
result =
Dart_SetField(library, DartUtils::NewString("_enableServicePortFallback"),
Dart_NewBoolean(enable_service_port_fallback));
SHUTDOWN_ON_ERROR(result);
if (write_service_info_filename != nullptr) {
result = DartUtils::SetStringField(library, "_serviceInfoFilename",
write_service_info_filename);
SHUTDOWN_ON_ERROR(result);
}
// Are we running on Windows?
#if defined(HOST_OS_WINDOWS)
Dart_Handle is_windows = Dart_True();
#else
Dart_Handle is_windows = Dart_False();
#endif
result =
Dart_SetField(library, DartUtils::NewString("_isWindows"), is_windows);
SHUTDOWN_ON_ERROR(result);
// Are we running on Fuchsia?
#if defined(HOST_OS_FUCHSIA)
Dart_Handle is_fuchsia = Dart_True();
#else
Dart_Handle is_fuchsia = Dart_False();
#endif
result =
Dart_SetField(library, DartUtils::NewString("_isFuchsia"), is_fuchsia);
SHUTDOWN_ON_ERROR(result);
// Get _getWatchSignalInternal from dart:io.
Dart_Handle dart_io_str = Dart_NewStringFromCString(DartUtils::kIOLibURL);
SHUTDOWN_ON_ERROR(dart_io_str);
Dart_Handle io_lib = Dart_LookupLibrary(dart_io_str);
SHUTDOWN_ON_ERROR(io_lib);
Dart_Handle function_name =
Dart_NewStringFromCString("_getWatchSignalInternal");
SHUTDOWN_ON_ERROR(function_name);
Dart_Handle signal_watch = Dart_Invoke(io_lib, function_name, 0, NULL);
SHUTDOWN_ON_ERROR(signal_watch);
Dart_Handle field_name = Dart_NewStringFromCString("_signalWatch");
SHUTDOWN_ON_ERROR(field_name);
result = Dart_SetField(library, field_name, signal_watch);
SHUTDOWN_ON_ERROR(field_name);
return true;
}
const char* VmService::GetErrorMessage() {
return (error_msg_ == NULL) ? "No error." : error_msg_;
}
void VmService::SetServerAddress(const char* server_uri) {
if (server_uri == NULL) {
server_uri = "";
}
const intptr_t server_uri_len = strlen(server_uri);
if (server_uri_len >= (kServerUriStringBufferSize - 1)) {
FATAL1("vm-service: Server URI exceeded length: %s\n", server_uri);
}
strncpy(server_uri_, server_uri, kServerUriStringBufferSize);
server_uri_[kServerUriStringBufferSize - 1] = '\0';
}
} // namespace bin
} // namespace dart