Add functions for communicating with the GnuPG agent

These functions are largely based on the gpgagent_* functions in
readerstatus.cpp in kleopatra.

GnuPG-bug-id: 5666

src/CMakeLists.txt

@@ -44,6 +44,7 @@ target_sources(KF5Libkleo PRIVATE
    models/keyrearrangecolumnsproxymodel.cpp
    models/subkeylistmodel.cpp
    models/useridlistmodel.cpp
+   utils/assuan.cpp
    utils/filesystemwatcher.cpp
    utils/formatting.cpp
    utils/classify.cpp
@@ -175,6 +176,7 @@ ecm_generate_headers(libkleo_CamelCase_models_HEADERS
 ecm_generate_headers(libkleo_CamelCase_utils_HEADERS
   HEADER_NAMES
   Algorithm
+  Assuan
   Classify
   CryptoConfig
   FileSystemWatcher

src/utils/assuan.cpp

+/*
+    utils/assuan.cpp
+
+    This file is part of libkleopatra
+    SPDX-FileCopyrightText: 2021 g10 Code GmbH
+    SPDX-FileContributor: Ingo Klöcker <dev@ingo-kloecker.de>
+
+    SPDX-License-Identifier: GPL-2.0-or-later
+*/
+
+#include <config-libkleo.h>
+
+#include "assuan.h"
+
+#include <QThread>
+
+#if __has_include(<QGpgME/Debug>)
+# include <QGpgME/Debug>
+#endif
+
+#include <gpgme++/defaultassuantransaction.h>
+#include <gpgme++/context.h>
+#include <gpgme++/error.h>
+
+#include "libkleo_debug.h"
+
+using namespace GpgME;
+using namespace Kleo;
+using namespace Kleo::Assuan;
+
+namespace
+{
+static QDebug operator<<(QDebug s, const std::string &string)
+{
+    return s << QString::fromStdString(string);
+}
+
+static QDebug operator<<(QDebug s, const std::vector< std::pair<std::string, std::string> > &v)
+{
+    using pair = std::pair<std::string, std::string>;
+    s << '(';
+    for (const pair &p : v) {
+        s << "status(" << QString::fromStdString(p.first) << ") =" << QString::fromStdString(p.second) << '\n';
+    }
+    return s << ')';
+}
+}
+
+std::unique_ptr<GpgME::AssuanTransaction> Kleo::Assuan::sendCommand(std::shared_ptr<GpgME::Context> &context, const std::string &command, std::unique_ptr<GpgME::AssuanTransaction> transaction, GpgME::Error &err)
+{
+    qCDebug(LIBKLEO_LOG) << __func__ << command;
+    err = context->assuanTransact(command.c_str(), std::move(transaction));
+
+    static int cnt = 0;
+    while (err.code() == GPG_ERR_ASS_CONNECT_FAILED && cnt < 5) {
+        // Esp. on Windows the agent processes may take their time so we try
+        // in increasing waits for them to start up
+        qCDebug(LIBKLEO_LOG) << "Waiting for the daemons to start up";
+        cnt++;
+        QThread::msleep(250 * cnt);
+        err = context->assuanTransact(command.c_str(), context->takeLastAssuanTransaction());
+    }
+    if (err.code()) {
+        qCDebug(LIBKLEO_LOG) << __func__ << command << "failed:" << err;
+        if (err.code() >= GPG_ERR_ASS_GENERAL && err.code() <= GPG_ERR_ASS_UNKNOWN_INQUIRE) {
+            qCDebug(LIBKLEO_LOG) << "Assuan problem, killing context";
+            context.reset();
+        }
+        return {};
+    }
+    return context->takeLastAssuanTransaction();
+}
+
+std::unique_ptr<DefaultAssuanTransaction> Kleo::Assuan::sendCommand(std::shared_ptr<Context> &context, const std::string &command, Error &err)
+{
+    std::unique_ptr<AssuanTransaction> t = sendCommand(context, command, std::make_unique<DefaultAssuanTransaction>(), err);
+    return std::unique_ptr<DefaultAssuanTransaction>(dynamic_cast<DefaultAssuanTransaction*>(t.release()));
+}
+
+std::string Kleo::Assuan::sendDataCommand(std::shared_ptr<Context> context, const std::string &command, Error &err)
+{
+    std::string data;
+    const std::unique_ptr<DefaultAssuanTransaction> t = sendCommand(context, command, err);
+    if (t.get()) {
+        data = t->data();
+        qCDebug(LIBKLEO_LOG) << __func__ << command << ": got" << QString::fromStdString(data);
+    } else {
+        qCDebug(LIBKLEO_LOG) << __func__ << command << ": t == NULL";
+    }
+    return data;
+}
+
+std::vector<std::pair<std::string, std::string>> Kleo::Assuan::sendStatusLinesCommand(std::shared_ptr<Context> context, const std::string &command, Error &err)
+{
+    std::vector<std::pair<std::string, std::string>> statusLines;
+    const std::unique_ptr<DefaultAssuanTransaction> t = sendCommand(context, command, err);
+    if (t.get()) {
+        statusLines = t->statusLines();
+        qCDebug(LIBKLEO_LOG) << __func__ << command << ": got" << statusLines;
+    } else {
+        qCDebug(LIBKLEO_LOG) << __func__ << command << ": t == NULL";
+    }
+    return statusLines;
+}
+
+std::string Kleo::Assuan::sendStatusCommand(const std::shared_ptr<Context> &context, const std::string &command, Error &err)
+{
+    const auto lines = sendStatusLinesCommand(context, command, err);
+    // The status is only the last attribute
+    // e.g. for SCD SERIALNO it would only be "SERIALNO" and for SCD GETATTR FOO
+    // it would only be FOO
+    const auto lastSpace = command.rfind(' ');
+    const auto needle = lastSpace == std::string::npos ? command : command.substr(lastSpace + 1);
+    for (const auto &pair: lines) {
+        if (pair.first == needle) {
+            return pair.second;
+        }
+    }
+    return {};
+}

src/utils/assuan.h

+/*
+    utils/assuan.h
+
+    This file is part of libkleopatra
+    SPDX-FileCopyrightText: 2021 g10 Code GmbH
+    SPDX-FileContributor: Ingo Klöcker <dev@ingo-kloecker.de>
+
+    SPDX-License-Identifier: GPL-2.0-or-later
+*/
+
+#pragma once
+
+#include <memory>
+#include <vector>
+
+#include "kleo_export.h"
+
+namespace GpgME
+{
+class AssuanTransaction;
+class Context;
+class DefaultAssuanTransaction;
+class Error;
+}
+
+namespace Kleo
+{
+/** The Assuan namespace collects functions for communicating with the GnuPG
+ *  agent via the Assuan protocol. */
+namespace Assuan
+{
+
+/** Sends the Assuan @p command using the @p transaction and the @p assuanContext
+ *  to the GnuPG agent and waits for the result. The returned transaction can be used
+ *  to retrieve the result.
+ *  If an error occurred, then @p err provides details. */
+KLEO_EXPORT std::unique_ptr<GpgME::AssuanTransaction> sendCommand(std::shared_ptr<GpgME::Context> &assuanContext, const std::string &command, std::unique_ptr<GpgME::AssuanTransaction> transaction, GpgME::Error &err);
+
+/** Sends the Assuan @p command using a default Assuan transaction and the @p assuanContext
+ *  to the GnuPG agent and waits for the result. The returned transaction can be used
+ *  to retrieve the result.
+ *  If an error occurred, then @p err provides details. */
+KLEO_EXPORT std::unique_ptr<GpgME::DefaultAssuanTransaction> sendCommand(std::shared_ptr<GpgME::Context> &assuanContext, const std::string &command, GpgME::Error &err);
+
+/** Sends the Assuan @p command using a default Assuan transaction and the @p assuanContext
+ *  to the GnuPG agent and waits for the result. Returns the data that was sent by
+ *  GnuPG agent in response to the @p command.
+ *  If an error occurred, then @p err provides details. */
+KLEO_EXPORT std::string sendDataCommand(std::shared_ptr<GpgME::Context> assuanContext, const std::string &command, GpgME::Error &err);
+
+/** Sends the Assuan @p command using a default Assuan transaction and the @p assuanContext
+ *  to the GnuPG agent and waits for the result. Returns the status lines that were sent by
+ *  GnuPG agent in response to the @p command.
+ *  If an error occurred, then @p err provides details. */
+KLEO_EXPORT std::vector<std::pair<std::string, std::string>> sendStatusLinesCommand(std::shared_ptr<GpgME::Context> assuanContext, const std::string &command, GpgME::Error &err);
+
+/** Sends the Assuan @p command using a default Assuan transaction and the @p assuanContext
+ *  to the GnuPG agent and waits for the result. Returns the status that was sent by
+ *  GnuPG agent in response to the @p command.
+ *  If an error occurred, then @p err provides details. */
+KLEO_EXPORT std::string sendStatusCommand(const std::shared_ptr<GpgME::Context> &assuanContext, const std::string &command, GpgME::Error &err);
+
+}
+}