X-Git-Url: https://git.josue.xyz/?p=VSoRC%2F.git;a=blobdiff_plain;f=node_modules%2Fnode-pty%2Fdeps%2Fwinpty%2Fsrc%2Flibwinpty%2Fwinpty.cc;fp=node_modules%2Fnode-pty%2Fdeps%2Fwinpty%2Fsrc%2Flibwinpty%2Fwinpty.cc;h=3d977498ef974c3ebf213f8a799fa29c57eb578f;hp=0000000000000000000000000000000000000000;hb=e79e4a5a87f3e84f7c1777f10a954453a69bf540;hpb=4339da12467b75fb8b6ca831f4bf0081c485ed2c

diff --git a/node_modules/node-pty/deps/winpty/src/libwinpty/winpty.cc b/node_modules/node-pty/deps/winpty/src/libwinpty/winpty.cc
new file mode 100644
index 0000000..3d97749
--- /dev/null
+++ b/node_modules/node-pty/deps/winpty/src/libwinpty/winpty.cc
@@ -0,0 +1,970 @@
+// Copyright (c) 2011-2016 Ryan Prichard
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to
+// deal in the Software without restriction, including without limitation the
+// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+// sell copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+// IN THE SOFTWARE.
+
+#include <windows.h>
+
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <limits>
+#include <string>
+#include <vector>
+
+#include "../include/winpty.h"
+
+#include "../shared/AgentMsg.h"
+#include "../shared/BackgroundDesktop.h"
+#include "../shared/Buffer.h"
+#include "../shared/DebugClient.h"
+#include "../shared/GenRandom.h"
+#include "../shared/OwnedHandle.h"
+#include "../shared/StringBuilder.h"
+#include "../shared/StringUtil.h"
+#include "../shared/WindowsSecurity.h"
+#include "../shared/WindowsVersion.h"
+#include "../shared/WinptyAssert.h"
+#include "../shared/WinptyException.h"
+#include "../shared/WinptyVersion.h"
+
+#include "AgentLocation.h"
+#include "LibWinptyException.h"
+#include "WinptyInternal.h"
+
+
+
+/*****************************************************************************
+ * Error handling -- translate C++ exceptions to an optional error object
+ * output and log the result. */
+
+static const winpty_error_s kOutOfMemory = {
+    WINPTY_ERROR_OUT_OF_MEMORY,
+    L"Out of memory",
+    nullptr
+};
+
+static const winpty_error_s kBadRpcPacket = {
+    WINPTY_ERROR_UNSPECIFIED,
+    L"Bad RPC packet",
+    nullptr
+};
+
+static const winpty_error_s kUncaughtException = {
+    WINPTY_ERROR_UNSPECIFIED,
+    L"Uncaught C++ exception",
+    nullptr
+};
+
+/* Gets the error code from the error object. */
+WINPTY_API winpty_result_t winpty_error_code(winpty_error_ptr_t err) {
+    return err != nullptr ? err->code : WINPTY_ERROR_SUCCESS;
+}
+
+/* Returns a textual representation of the error.  The string is freed when
+ * the error is freed. */
+WINPTY_API LPCWSTR winpty_error_msg(winpty_error_ptr_t err) {
+    if (err != nullptr) {
+        if (err->msgStatic != nullptr) {
+            return err->msgStatic;
+        } else {
+            ASSERT(err->msgDynamic != nullptr);
+            std::wstring *msgPtr = err->msgDynamic->get();
+            ASSERT(msgPtr != nullptr);
+            return msgPtr->c_str();
+        }
+    } else {
+        return L"Success";
+    }
+}
+
+/* Free the error object.  Every error returned from the winpty API must be
+ * freed. */
+WINPTY_API void winpty_error_free(winpty_error_ptr_t err) {
+    if (err != nullptr && err->msgDynamic != nullptr) {
+        delete err->msgDynamic;
+        delete err;
+    }
+}
+
+static void translateException(winpty_error_ptr_t *&err) {
+    winpty_error_ptr_t ret = nullptr;
+    try {
+        try {
+            throw;
+        } catch (const ReadBuffer::DecodeError&) {
+            ret = const_cast<winpty_error_ptr_t>(&kBadRpcPacket);
+        } catch (const LibWinptyException &e) {
+            std::unique_ptr<winpty_error_t> obj(new winpty_error_t);
+            obj->code = e.code();
+            obj->msgStatic = nullptr;
+            obj->msgDynamic =
+                new std::shared_ptr<std::wstring>(e.whatSharedStr());
+            ret = obj.release();
+        } catch (const WinptyException &e) {
+            std::unique_ptr<winpty_error_t> obj(new winpty_error_t);
+            std::shared_ptr<std::wstring> msg(new std::wstring(e.what()));
+            obj->code = WINPTY_ERROR_UNSPECIFIED;
+            obj->msgStatic = nullptr;
+            obj->msgDynamic = new std::shared_ptr<std::wstring>(msg);
+            ret = obj.release();
+        }
+    } catch (const std::bad_alloc&) {
+        ret = const_cast<winpty_error_ptr_t>(&kOutOfMemory);
+    } catch (...) {
+        ret = const_cast<winpty_error_ptr_t>(&kUncaughtException);
+    }
+    trace("libwinpty error: code=%u msg='%s'",
+        static_cast<unsigned>(ret->code),
+        utf8FromWide(winpty_error_msg(ret)).c_str());
+    if (err != nullptr) {
+        *err = ret;
+    } else {
+        winpty_error_free(ret);
+    }
+}
+
+#define API_TRY \
+    if (err != nullptr) { *err = nullptr; } \
+    try
+
+#define API_CATCH(ret) \
+    catch (...) { translateException(err); return (ret); }
+
+
+
+/*****************************************************************************
+ * Configuration of a new agent. */
+
+WINPTY_API winpty_config_t *
+winpty_config_new(UINT64 flags, winpty_error_ptr_t *err /*OPTIONAL*/) {
+    API_TRY {
+        ASSERT((flags & WINPTY_FLAG_MASK) == flags);
+        std::unique_ptr<winpty_config_t> ret(new winpty_config_t);
+        ret->flags = flags;
+        return ret.release();
+    } API_CATCH(nullptr)
+}
+
+WINPTY_API void winpty_config_free(winpty_config_t *cfg) {
+    delete cfg;
+}
+
+WINPTY_API void
+winpty_config_set_initial_size(winpty_config_t *cfg, int cols, int rows) {
+    ASSERT(cfg != nullptr && cols > 0 && rows > 0);
+    cfg->cols = cols;
+    cfg->rows = rows;
+}
+
+WINPTY_API void
+winpty_config_set_mouse_mode(winpty_config_t *cfg, int mouseMode) {
+    ASSERT(cfg != nullptr &&
+        mouseMode >= WINPTY_MOUSE_MODE_NONE &&
+        mouseMode <= WINPTY_MOUSE_MODE_FORCE);
+    cfg->mouseMode = mouseMode;
+}
+
+WINPTY_API void
+winpty_config_set_agent_timeout(winpty_config_t *cfg, DWORD timeoutMs) {
+    ASSERT(cfg != nullptr && timeoutMs > 0);
+    cfg->timeoutMs = timeoutMs;
+}
+
+
+
+/*****************************************************************************
+ * Agent I/O. */
+
+namespace {
+
+// Once an I/O operation fails with ERROR_IO_PENDING, the caller *must* wait
+// for it to complete, even after calling CancelIo on it!  See
+// https://blogs.msdn.microsoft.com/oldnewthing/20110202-00/?p=11613.  This
+// class enforces that requirement.
+class PendingIo {
+    HANDLE m_file;
+    OVERLAPPED &m_over;
+    bool m_finished;
+public:
+    // The file handle and OVERLAPPED object must live as long as the PendingIo
+    // object.
+    PendingIo(HANDLE file, OVERLAPPED &over) :
+        m_file(file), m_over(over), m_finished(false) {}
+    ~PendingIo() {
+        if (!m_finished) {
+            // We're not usually that interested in CancelIo's return value.
+            // In any case, we must not throw an exception in this dtor.
+            CancelIo(m_file);
+            waitForCompletion();
+        }
+    }
+    std::tuple<BOOL, DWORD> waitForCompletion(DWORD &actual) WINPTY_NOEXCEPT {
+        m_finished = true;
+        const BOOL success =
+            GetOverlappedResult(m_file, &m_over, &actual, TRUE);
+        return std::make_tuple(success, GetLastError());
+    }
+    std::tuple<BOOL, DWORD> waitForCompletion() WINPTY_NOEXCEPT {
+        DWORD actual = 0;
+        return waitForCompletion(actual);
+    }
+};
+
+} // anonymous namespace
+
+static void handlePendingIo(winpty_t &wp, OVERLAPPED &over, BOOL &success,
+                            DWORD &lastError, DWORD &actual) {
+    if (!success && lastError == ERROR_IO_PENDING) {
+        PendingIo io(wp.controlPipe.get(), over);
+        const HANDLE waitHandles[2] = { wp.ioEvent.get(),
+                                        wp.agentProcess.get() };
+        DWORD waitRet = WaitForMultipleObjects(
+            2, waitHandles, FALSE, wp.agentTimeoutMs);
+        if (waitRet != WAIT_OBJECT_0) {
+            // The I/O is still pending.  Cancel it, close the I/O event, and
+            // throw an exception.
+            if (waitRet == WAIT_OBJECT_0 + 1) {
+                throw LibWinptyException(WINPTY_ERROR_AGENT_DIED, L"agent died");
+            } else if (waitRet == WAIT_TIMEOUT) {
+                throw LibWinptyException(WINPTY_ERROR_AGENT_TIMEOUT,
+                                      L"agent timed out");
+            } else if (waitRet == WAIT_FAILED) {
+                throwWindowsError(L"WaitForMultipleObjects failed");
+            } else {
+                ASSERT(false &&
+                    "unexpected WaitForMultipleObjects return value");
+            }
+        }
+        std::tie(success, lastError) = io.waitForCompletion(actual);
+    }
+}
+
+static void handlePendingIo(winpty_t &wp, OVERLAPPED &over, BOOL &success,
+                            DWORD &lastError) {
+    DWORD actual = 0;
+    handlePendingIo(wp, over, success, lastError, actual);
+}
+
+static void handleReadWriteErrors(winpty_t &wp, BOOL success, DWORD lastError,
+                                  const wchar_t *genericErrMsg) {
+    if (!success) {
+        // If the pipe connection is broken after it's been connected, then
+        // later I/O operations fail with ERROR_BROKEN_PIPE (reads) or
+        // ERROR_NO_DATA (writes).  With Wine, they may also fail with
+        // ERROR_PIPE_NOT_CONNECTED.  See this gist[1].
+        //
+        // [1] https://gist.github.com/rprichard/8dd8ca134b39534b7da2733994aa07ba
+        if (lastError == ERROR_BROKEN_PIPE || lastError == ERROR_NO_DATA ||
+                lastError == ERROR_PIPE_NOT_CONNECTED) {
+            throw LibWinptyException(WINPTY_ERROR_LOST_CONNECTION,
+                L"lost connection to agent");
+        } else {
+            throwWindowsError(genericErrMsg, lastError);
+        }
+    }
+}
+
+// Calls ConnectNamedPipe to wait until the agent connects to the control pipe.
+static void
+connectControlPipe(winpty_t &wp) {
+    OVERLAPPED over = {};
+    over.hEvent = wp.ioEvent.get();
+    BOOL success = ConnectNamedPipe(wp.controlPipe.get(), &over);
+    DWORD lastError = GetLastError();
+    handlePendingIo(wp, over, success, lastError);
+    if (!success && lastError == ERROR_PIPE_CONNECTED) {
+        success = TRUE;
+    }
+    if (!success) {
+        throwWindowsError(L"ConnectNamedPipe failed", lastError);
+    }
+}
+
+static void writeData(winpty_t &wp, const void *data, size_t amount) {
+    // Perform a single pipe write.
+    DWORD actual = 0;
+    OVERLAPPED over = {};
+    over.hEvent = wp.ioEvent.get();
+    BOOL success = WriteFile(wp.controlPipe.get(), data, amount,
+                             &actual, &over);
+    DWORD lastError = GetLastError();
+    if (!success) {
+        handlePendingIo(wp, over, success, lastError, actual);
+        handleReadWriteErrors(wp, success, lastError, L"WriteFile failed");
+        ASSERT(success);
+    }
+    // TODO: Can a partial write actually happen somehow?
+    ASSERT(actual == amount && "WriteFile wrote fewer bytes than requested");
+}
+
+static inline WriteBuffer newPacket() {
+    WriteBuffer packet;
+    packet.putRawValue<uint64_t>(0); // Reserve space for size.
+    return packet;
+}
+
+static void writePacket(winpty_t &wp, WriteBuffer &packet) {
+    const auto &buf = packet.buf();
+    packet.replaceRawValue<uint64_t>(0, buf.size());
+    writeData(wp, buf.data(), buf.size());
+}
+
+static size_t readData(winpty_t &wp, void *data, size_t amount) {
+    DWORD actual = 0;
+    OVERLAPPED over = {};
+    over.hEvent = wp.ioEvent.get();
+    BOOL success = ReadFile(wp.controlPipe.get(), data, amount,
+                            &actual, &over);
+    DWORD lastError = GetLastError();
+    if (!success) {
+        handlePendingIo(wp, over, success, lastError, actual);
+        handleReadWriteErrors(wp, success, lastError, L"ReadFile failed");
+    }
+    return actual;
+}
+
+static void readAll(winpty_t &wp, void *data, size_t amount) {
+    while (amount > 0) {
+        const size_t chunk = readData(wp, data, amount);
+        ASSERT(chunk <= amount && "readData result is larger than amount");
+        data = reinterpret_cast<char*>(data) + chunk;
+        amount -= chunk;
+    }
+}
+
+static uint64_t readUInt64(winpty_t &wp) {
+    uint64_t ret = 0;
+    readAll(wp, &ret, sizeof(ret));
+    return ret;
+}
+
+// Returns a reply packet's payload.
+static ReadBuffer readPacket(winpty_t &wp) {
+    const uint64_t packetSize = readUInt64(wp);
+    if (packetSize < sizeof(packetSize) || packetSize > SIZE_MAX) {
+        throwWinptyException(L"Agent RPC error: invalid packet size");
+    }
+    const size_t payloadSize = packetSize - sizeof(packetSize);
+    std::vector<char> bytes(payloadSize);
+    readAll(wp, bytes.data(), bytes.size());
+    return ReadBuffer(std::move(bytes));
+}
+
+static OwnedHandle createControlPipe(const std::wstring &name) {
+    const auto sd = createPipeSecurityDescriptorOwnerFullControl();
+    if (!sd) {
+        throwWinptyException(
+            L"could not create the control pipe's SECURITY_DESCRIPTOR");
+    }
+    SECURITY_ATTRIBUTES sa = {};
+    sa.nLength = sizeof(sa);
+    sa.lpSecurityDescriptor = sd.get();
+    HANDLE ret = CreateNamedPipeW(name.c_str(),
+        /*dwOpenMode=*/
+        PIPE_ACCESS_DUPLEX |
+            FILE_FLAG_FIRST_PIPE_INSTANCE |
+            FILE_FLAG_OVERLAPPED,
+        /*dwPipeMode=*/rejectRemoteClientsPipeFlag(),
+        /*nMaxInstances=*/1,
+        /*nOutBufferSize=*/8192,
+        /*nInBufferSize=*/256,
+        /*nDefaultTimeOut=*/30000,
+        &sa);
+    if (ret == INVALID_HANDLE_VALUE) {
+        throwWindowsError(L"CreateNamedPipeW failed");
+    }
+    return OwnedHandle(ret);
+}
+
+
+
+/*****************************************************************************
+ * Start the agent. */
+
+static OwnedHandle createEvent() {
+    // manual reset, initially unset
+    HANDLE h = CreateEventW(nullptr, TRUE, FALSE, nullptr);
+    if (h == nullptr) {
+        throwWindowsError(L"CreateEventW failed");
+    }
+    return OwnedHandle(h);
+}
+
+// For debugging purposes, provide a way to keep the console on the main window
+// station, visible.
+static bool shouldShowConsoleWindow() {
+    char buf[32];
+    return GetEnvironmentVariableA("WINPTY_SHOW_CONSOLE", buf, sizeof(buf)) > 0;
+}
+
+static bool shouldCreateBackgroundDesktop(bool &createUsingAgent) {
+    // Prior to Windows 7, winpty's repeated selection-deselection loop
+    // prevented the user from interacting with their *visible* console
+    // windows, unless we placed the console onto a background desktop.
+    // The SetProcessWindowStation call interferes with the clipboard and
+    // isn't thread-safe, though[1].  The call should perhaps occur in a
+    // special agent subprocess.  Spawning a process in a background desktop
+    // also breaks ConEmu, but marking the process SW_HIDE seems to correct
+    // that[2].
+    //
+    // Windows 7 moved a lot of console handling out of csrss.exe and into
+    // a per-console conhost.exe process, which may explain why it isn't
+    // affected.
+    //
+    // This is a somewhat risky change, so there are low-level flags to
+    // assist in debugging if there are issues.
+    //
+    // [1] https://github.com/rprichard/winpty/issues/58
+    // [2] https://github.com/rprichard/winpty/issues/70
+    bool ret = !shouldShowConsoleWindow() && !isAtLeastWindows7();
+    const bool force = hasDebugFlag("force_desktop");
+    const bool force_spawn = hasDebugFlag("force_desktop_spawn");
+    const bool force_curproc = hasDebugFlag("force_desktop_curproc");
+    const bool suppress = hasDebugFlag("no_desktop");
+    if (force + force_spawn + force_curproc + suppress > 1) {
+        trace("error: Only one of force_desktop, force_desktop_spawn, "
+              "force_desktop_curproc, and no_desktop may be set");
+    } else if (force) {
+        ret = true;
+    } else if (force_spawn) {
+        ret = true;
+        createUsingAgent = true;
+    } else if (force_curproc) {
+        ret = true;
+        createUsingAgent = false;
+    } else if (suppress) {
+        ret = false;
+    }
+    return ret;
+}
+
+static bool shouldSpecifyHideFlag() {
+    const bool force = hasDebugFlag("force_sw_hide");
+    const bool suppress = hasDebugFlag("no_sw_hide");
+    bool ret = !shouldShowConsoleWindow();
+    if (force && suppress) {
+        trace("error: Both the force_sw_hide and no_sw_hide flags are set");
+    } else if (force) {
+        ret = true;
+    } else if (suppress) {
+        ret = false;
+    }
+    return ret;
+}
+
+static OwnedHandle startAgentProcess(
+        const std::wstring &desktop,
+        const std::wstring &controlPipeName,
+        const std::wstring &params,
+        DWORD creationFlags,
+        DWORD &agentPid) {
+    const std::wstring exePath = findAgentProgram();
+    const std::wstring cmdline =
+        (WStringBuilder(256)
+            << L"\"" << exePath << L"\" "
+            << controlPipeName << L' '
+            << params).str_moved();
+
+    auto cmdlineV = vectorWithNulFromString(cmdline);
+    auto desktopV = vectorWithNulFromString(desktop);
+
+    // Start the agent.
+    STARTUPINFOW sui = {};
+    sui.cb = sizeof(sui);
+    sui.lpDesktop = desktop.empty() ? nullptr : desktopV.data();
+
+    if (shouldSpecifyHideFlag()) {
+        sui.dwFlags |= STARTF_USESHOWWINDOW;
+        sui.wShowWindow = SW_HIDE;
+    }
+    PROCESS_INFORMATION pi = {};
+    const BOOL success =
+        CreateProcessW(exePath.c_str(),
+                       cmdlineV.data(),
+                       nullptr, nullptr,
+                       /*bInheritHandles=*/FALSE,
+                       /*dwCreationFlags=*/creationFlags,
+                       nullptr, nullptr,
+                       &sui, &pi);
+    if (!success) {
+        const DWORD lastError = GetLastError();
+        const auto errStr =
+            (WStringBuilder(256)
+                << L"winpty-agent CreateProcess failed: cmdline='" << cmdline
+                << L"' err=0x" << whexOfInt(lastError)).str_moved();
+        throw LibWinptyException(
+            WINPTY_ERROR_AGENT_CREATION_FAILED, errStr.c_str());
+    }
+    CloseHandle(pi.hThread);
+    TRACE("Created agent successfully, pid=%u, cmdline=%s",
+          static_cast<unsigned int>(pi.dwProcessId),
+          utf8FromWide(cmdline).c_str());
+    agentPid = pi.dwProcessId;
+    return OwnedHandle(pi.hProcess);
+}
+
+static void verifyPipeClientPid(HANDLE serverPipe, DWORD agentPid) {
+    const auto client = getNamedPipeClientProcessId(serverPipe);
+    const auto success = std::get<0>(client);
+    const auto lastError = std::get<2>(client);
+    if (success == GetNamedPipeClientProcessId_Result::Success) {
+        const auto clientPid = std::get<1>(client);
+        if (clientPid != agentPid) {
+            WStringBuilder errMsg;
+            errMsg << L"Security check failed: pipe client pid (" << clientPid
+                   << L") does not match agent pid (" << agentPid << L")";
+            throwWinptyException(errMsg.c_str());
+        }
+    } else if (success == GetNamedPipeClientProcessId_Result::UnsupportedOs) {
+        trace("Pipe client PID security check skipped: "
+            "GetNamedPipeClientProcessId unsupported on this OS version");
+    } else {
+        throwWindowsError(L"GetNamedPipeClientProcessId failed", lastError);
+    }
+}
+
+static std::unique_ptr<winpty_t>
+createAgentSession(const winpty_config_t *cfg,
+                   const std::wstring &desktop,
+                   const std::wstring &params,
+                   DWORD creationFlags) {
+    std::unique_ptr<winpty_t> wp(new winpty_t);
+    wp->agentTimeoutMs = cfg->timeoutMs;
+    wp->ioEvent = createEvent();
+
+    // Create control server pipe.
+    const auto pipeName =
+        L"\\\\.\\pipe\\winpty-control-" + GenRandom().uniqueName();
+    wp->controlPipe = createControlPipe(pipeName);
+
+    DWORD agentPid = 0;
+    wp->agentProcess = startAgentProcess(
+        desktop, pipeName, params, creationFlags, agentPid);
+    connectControlPipe(*wp.get());
+    verifyPipeClientPid(wp->controlPipe.get(), agentPid);
+
+    return std::move(wp);
+}
+
+namespace {
+
+class AgentDesktop {
+public:
+    virtual std::wstring name() = 0;
+    virtual ~AgentDesktop() {}
+};
+
+class AgentDesktopDirect : public AgentDesktop {
+public:
+    AgentDesktopDirect(BackgroundDesktop &&desktop) :
+        m_desktop(std::move(desktop))
+    {
+    }
+    std::wstring name() override { return m_desktop.desktopName(); }
+private:
+    BackgroundDesktop m_desktop;
+};
+
+class AgentDesktopIndirect : public AgentDesktop {
+public:
+    AgentDesktopIndirect(std::unique_ptr<winpty_t> &&wp,
+                         std::wstring &&desktopName) :
+        m_wp(std::move(wp)),
+        m_desktopName(std::move(desktopName))
+    {
+    }
+    std::wstring name() override { return m_desktopName; }
+private:
+    std::unique_ptr<winpty_t> m_wp;
+    std::wstring m_desktopName;
+};
+
+} // anonymous namespace
+
+std::unique_ptr<AgentDesktop>
+setupBackgroundDesktop(const winpty_config_t *cfg) {
+    bool useDesktopAgent =
+        !(cfg->flags & WINPTY_FLAG_ALLOW_CURPROC_DESKTOP_CREATION);
+    const bool useDesktop = shouldCreateBackgroundDesktop(useDesktopAgent);
+
+    if (!useDesktop) {
+        return std::unique_ptr<AgentDesktop>();
+    }
+
+    if (useDesktopAgent) {
+        auto wp = createAgentSession(
+            cfg, std::wstring(), L"--create-desktop", DETACHED_PROCESS);
+
+        // Read the desktop name.
+        auto packet = readPacket(*wp.get());
+        auto desktopName = packet.getWString();
+        packet.assertEof();
+
+        if (desktopName.empty()) {
+            return std::unique_ptr<AgentDesktop>();
+        } else {
+            return std::unique_ptr<AgentDesktop>(
+                new AgentDesktopIndirect(std::move(wp),
+                                         std::move(desktopName)));
+        }
+    } else {
+        try {
+            BackgroundDesktop desktop;
+            return std::unique_ptr<AgentDesktop>(new AgentDesktopDirect(
+                std::move(desktop)));
+        } catch (const WinptyException &e) {
+            trace("Error: failed to create background desktop, "
+                  "using original desktop instead: %s",
+                  utf8FromWide(e.what()).c_str());
+            return std::unique_ptr<AgentDesktop>();
+        }
+    }
+}
+
+WINPTY_API winpty_t *
+winpty_open(const winpty_config_t *cfg,
+            winpty_error_ptr_t *err /*OPTIONAL*/) {
+    API_TRY {
+        ASSERT(cfg != nullptr);
+        dumpWindowsVersion();
+        dumpVersionToTrace();
+
+        // Setup a background desktop for the agent.
+        auto desktop = setupBackgroundDesktop(cfg);
+        const auto desktopName = desktop ? desktop->name() : std::wstring();
+
+        // Start the primary agent session.
+        const auto params =
+            (WStringBuilder(128)
+                << cfg->flags << L' '
+                << cfg->mouseMode << L' '
+                << cfg->cols << L' '
+                << cfg->rows).str_moved();
+        auto wp = createAgentSession(cfg, desktopName, params,
+                                     CREATE_NEW_CONSOLE);
+
+        // Close handles to the background desktop and restore the original
+        // window station.  This must wait until we know the agent is running
+        // -- if we close these handles too soon, then the desktop and
+        // windowstation will be destroyed before the agent can connect with
+        // them.
+        //
+        // If we used a separate agent process to create the desktop, we
+        // disconnect from that process here, allowing it to exit.
+        desktop.reset();
+
+        // If we ran the agent process on a background desktop, then when we
+        // spawn a child process from the agent, it will need to be explicitly
+        // placed back onto the original desktop.
+        if (!desktopName.empty()) {
+            wp->spawnDesktopName = getCurrentDesktopName();
+        }
+
+        // Get the CONIN/CONOUT pipe names.
+        auto packet = readPacket(*wp.get());
+        wp->coninPipeName = packet.getWString();
+        wp->conoutPipeName = packet.getWString();
+        if (cfg->flags & WINPTY_FLAG_CONERR) {
+            wp->conerrPipeName = packet.getWString();
+        }
+        packet.assertEof();
+
+        return wp.release();
+    } API_CATCH(nullptr)
+}
+
+WINPTY_API HANDLE winpty_agent_process(winpty_t *wp) {
+    ASSERT(wp != nullptr);
+    return wp->agentProcess.get();
+}
+
+
+
+/*****************************************************************************
+ * I/O pipes. */
+
+static const wchar_t *cstrFromWStringOrNull(const std::wstring &str) {
+    try {
+        return str.c_str();
+    } catch (const std::bad_alloc&) {
+        return nullptr;
+    }
+}
+
+WINPTY_API LPCWSTR winpty_conin_name(winpty_t *wp) {
+    ASSERT(wp != nullptr);
+    return cstrFromWStringOrNull(wp->coninPipeName);
+}
+
+WINPTY_API LPCWSTR winpty_conout_name(winpty_t *wp) {
+    ASSERT(wp != nullptr);
+    return cstrFromWStringOrNull(wp->conoutPipeName);
+}
+
+WINPTY_API LPCWSTR winpty_conerr_name(winpty_t *wp) {
+    ASSERT(wp != nullptr);
+    if (wp->conerrPipeName.empty()) {
+        return nullptr;
+    } else {
+        return cstrFromWStringOrNull(wp->conerrPipeName);
+    }
+}
+
+
+
+/*****************************************************************************
+ * winpty agent RPC calls. */
+
+namespace {
+
+// Close the control pipe if something goes wrong with the pipe communication,
+// which could leave the control pipe in an inconsistent state.
+class RpcOperation {
+public:
+    RpcOperation(winpty_t &wp) : m_wp(wp) {
+        if (m_wp.controlPipe.get() == nullptr) {
+            throwWinptyException(L"Agent shutdown due to RPC failure");
+        }
+    }
+    ~RpcOperation() {
+        if (!m_success) {
+            trace("~RpcOperation: Closing control pipe");
+            m_wp.controlPipe.dispose(true);
+        }
+    }
+    void success() { m_success = true; }
+private:
+    winpty_t &m_wp;
+    bool m_success = false;
+};
+
+} // anonymous namespace
+
+
+
+/*****************************************************************************
+ * winpty agent RPC call: process creation. */
+
+// Return a std::wstring containing every character of the environment block.
+// Typically, the block is non-empty, so the std::wstring returned ends with
+// two NUL terminators.  (These two terminators are counted in size(), so
+// calling c_str() produces a triply-terminated string.)
+static std::wstring wstringFromEnvBlock(const wchar_t *env) {
+    std::wstring envStr;
+    if (env != NULL) {
+        const wchar_t *p = env;
+        while (*p != L'\0') {
+            p += wcslen(p) + 1;
+        }
+        p++;
+        envStr.assign(env, p);
+
+        // Assuming the environment was non-empty, envStr now ends with two NUL
+        // terminators.
+        //
+        // If the environment were empty, though, then envStr would only be
+        // singly terminated, but the MSDN documentation thinks an env block is
+        // always doubly-terminated, so add an extra NUL just in case it
+        // matters.
+        const auto envStrSz = envStr.size();
+        if (envStrSz == 1) {
+            ASSERT(envStr[0] == L'\0');
+            envStr.push_back(L'\0');
+        } else {
+            ASSERT(envStrSz >= 3);
+            ASSERT(envStr[envStrSz - 3] != L'\0');
+            ASSERT(envStr[envStrSz - 2] == L'\0');
+            ASSERT(envStr[envStrSz - 1] == L'\0');
+        }
+    }
+    return envStr;
+}
+
+WINPTY_API winpty_spawn_config_t *
+winpty_spawn_config_new(UINT64 winptyFlags,
+                        LPCWSTR appname /*OPTIONAL*/,
+                        LPCWSTR cmdline /*OPTIONAL*/,
+                        LPCWSTR cwd /*OPTIONAL*/,
+                        LPCWSTR env /*OPTIONAL*/,
+                        winpty_error_ptr_t *err /*OPTIONAL*/) {
+    API_TRY {
+        ASSERT((winptyFlags & WINPTY_SPAWN_FLAG_MASK) == winptyFlags);
+        std::unique_ptr<winpty_spawn_config_t> cfg(new winpty_spawn_config_t);
+        cfg->winptyFlags = winptyFlags;
+        if (appname != nullptr) { cfg->appname = appname; }
+        if (cmdline != nullptr) { cfg->cmdline = cmdline; }
+        if (cwd != nullptr) { cfg->cwd = cwd; }
+        if (env != nullptr) { cfg->env = wstringFromEnvBlock(env); }
+        return cfg.release();
+    } API_CATCH(nullptr)
+}
+
+WINPTY_API void winpty_spawn_config_free(winpty_spawn_config_t *cfg) {
+    delete cfg;
+}
+
+// It's safe to truncate a handle from 64-bits to 32-bits, or to sign-extend it
+// back to 64-bits.  See the MSDN article, "Interprocess Communication Between
+// 32-bit and 64-bit Applications".
+// https://msdn.microsoft.com/en-us/library/windows/desktop/aa384203.aspx
+static inline HANDLE handleFromInt64(int64_t i) {
+    return reinterpret_cast<HANDLE>(static_cast<intptr_t>(i));
+}
+
+// Given a process and a handle in that process, duplicate the handle into the
+// current process and close it in the originating process.
+static inline OwnedHandle stealHandle(HANDLE process, HANDLE handle) {
+    HANDLE result = nullptr;
+    if (!DuplicateHandle(process, handle,
+            GetCurrentProcess(),
+            &result, 0, FALSE,
+            DUPLICATE_CLOSE_SOURCE | DUPLICATE_SAME_ACCESS)) {
+        throwWindowsError(L"DuplicateHandle of process handle");
+    }
+    return OwnedHandle(result);
+}
+
+WINPTY_API BOOL
+winpty_spawn(winpty_t *wp,
+             const winpty_spawn_config_t *cfg,
+             HANDLE *process_handle /*OPTIONAL*/,
+             HANDLE *thread_handle /*OPTIONAL*/,
+             DWORD *create_process_error /*OPTIONAL*/,
+             winpty_error_ptr_t *err /*OPTIONAL*/) {
+    API_TRY {
+        ASSERT(wp != nullptr && cfg != nullptr);
+
+        if (process_handle != nullptr) { *process_handle = nullptr; }
+        if (thread_handle != nullptr) { *thread_handle = nullptr; }
+        if (create_process_error != nullptr) { *create_process_error = 0; }
+
+        LockGuard<Mutex> lock(wp->mutex);
+        RpcOperation rpc(*wp);
+
+        // Send spawn request.
+        auto packet = newPacket();
+        packet.putInt32(AgentMsg::StartProcess);
+        packet.putInt64(cfg->winptyFlags);
+        packet.putInt32(process_handle != nullptr);
+        packet.putInt32(thread_handle != nullptr);
+        packet.putWString(cfg->appname);
+        packet.putWString(cfg->cmdline);
+        packet.putWString(cfg->cwd);
+        packet.putWString(cfg->env);
+        packet.putWString(wp->spawnDesktopName);
+        writePacket(*wp, packet);
+
+        // Receive reply.
+        auto reply = readPacket(*wp);
+        const auto result = static_cast<StartProcessResult>(reply.getInt32());
+        if (result == StartProcessResult::CreateProcessFailed) {
+            const DWORD lastError = reply.getInt32();
+            reply.assertEof();
+            if (create_process_error != nullptr) {
+                *create_process_error = lastError;
+            }
+            rpc.success();
+            throw LibWinptyException(WINPTY_ERROR_SPAWN_CREATE_PROCESS_FAILED,
+                L"CreateProcess failed");
+        } else if (result == StartProcessResult::ProcessCreated) {
+            const HANDLE remoteProcess = handleFromInt64(reply.getInt64());
+            const HANDLE remoteThread = handleFromInt64(reply.getInt64());
+            reply.assertEof();
+            OwnedHandle localProcess;
+            OwnedHandle localThread;
+            if (remoteProcess != nullptr) {
+                localProcess =
+                    stealHandle(wp->agentProcess.get(), remoteProcess);
+            }
+            if (remoteThread != nullptr) {
+                localThread =
+                    stealHandle(wp->agentProcess.get(), remoteThread);
+            }
+            if (process_handle != nullptr) {
+                *process_handle = localProcess.release();
+            }
+            if (thread_handle != nullptr) {
+                *thread_handle = localThread.release();
+            }
+            rpc.success();
+        } else {
+            throwWinptyException(
+                L"Agent RPC error: invalid StartProcessResult");
+        }
+        return TRUE;
+    } API_CATCH(FALSE)
+}
+
+
+
+/*****************************************************************************
+ * winpty agent RPC calls: everything else */
+
+WINPTY_API BOOL
+winpty_set_size(winpty_t *wp, int cols, int rows,
+                winpty_error_ptr_t *err /*OPTIONAL*/) {
+    API_TRY {
+        ASSERT(wp != nullptr && cols > 0 && rows > 0);
+        LockGuard<Mutex> lock(wp->mutex);
+        RpcOperation rpc(*wp);
+        auto packet = newPacket();
+        packet.putInt32(AgentMsg::SetSize);
+        packet.putInt32(cols);
+        packet.putInt32(rows);
+        writePacket(*wp, packet);
+        readPacket(*wp).assertEof();
+        rpc.success();
+        return TRUE;
+    } API_CATCH(FALSE)
+}
+
+WINPTY_API int
+winpty_get_console_process_list(winpty_t *wp, int *processList, const int processCount,
+                                winpty_error_ptr_t *err /*OPTIONAL*/) {
+    API_TRY {
+        ASSERT(wp != nullptr);
+        ASSERT(processList != nullptr);
+        LockGuard<Mutex> lock(wp->mutex);
+        RpcOperation rpc(*wp);
+        auto packet = newPacket();
+        packet.putInt32(AgentMsg::GetConsoleProcessList);
+        writePacket(*wp, packet);
+        auto reply = readPacket(*wp);
+
+        auto actualProcessCount = reply.getInt32();
+
+        if (actualProcessCount <= processCount) {
+            for (auto i = 0; i < actualProcessCount; i++) {
+                processList[i] = reply.getInt32();
+            }
+        }
+
+        reply.assertEof();
+        rpc.success();
+        return actualProcessCount;
+    } API_CATCH(0)
+}
+
+WINPTY_API void winpty_free(winpty_t *wp) {
+    // At least in principle, CloseHandle can fail, so this deletion can
+    // fail.  It won't throw an exception, but maybe there's an error that
+    // should be propagated?
+    delete wp;
+}