D-Bus: add helper's stdout to parent's stdout

During normal operation, the helper's messages were never printed to any
output stream. They only went out via D-Bus. This was surprising when
debugging syncevo-dbus-server and it's interaction with syncevo-dbus-helper.

It's better to let the parent print the helper's output if the helper
doesn't do it itself, so that console output is the same with and without
SYNCEVOLUTION_DEBUG.

2 files changed, 39 insertions, 6 deletions

diff --git a/src/dbus/server/session-helper.cpp b/src/dbus/server/session-helper.cpp
index 0ae993d9..4507576f 100644
--- a/src/dbus/server/session-helper.cpp
+++ b/src/dbus/server/session-helper.cpp
@@ -67,8 +67,15 @@ public:
         static bool dbg = getenv("SYNCEVOLUTION_DEBUG");
 
         if (dbg) {
-            // let parent LogRedirect or utility function handle the output *in addition* to
-            // logging via D-Bus
+            // Let parent LogRedirect or utility function handle the
+            // output *in addition* to logging via D-Bus. That way
+            // it'll be visible via our stdout/stderr (= console)
+            // right away.
+            //
+            // In non-debug mode, nothing should get written to
+            // stdout/stder, which got redirected into a pipe
+            // read by our parend. In that mode, the parent will include
+            // our output in its own output streams.
             va_list argsCopy;
             va_copy(argsCopy, args);
             if (m_parentLogger) {
diff --git a/src/dbus/server/session.cpp b/src/dbus/server/session.cpp
index e5513372..8b2394c7 100644
--- a/src/dbus/server/session.cpp
+++ b/src/dbus/server/session.cpp
@@ -819,16 +819,42 @@ void Session::messagev(const MessageOptions &options,
                           getPath(), "");
 }
 
+static void Logging2ServerAndStdout(Server &server,
+                                    const GDBusCXX::DBusObject_t &path,
+                                    const Logger::MessageOptions &options,
+                                    const char *format,
+                                    ...)
+{
+    va_list args;
+    va_start(args, format);
+    server.message2DBus(options, format, args, path, options.m_processName ? *options.m_processName : "");
+    va_end(args);
+}
+
 static void Logging2Server(Server &server,
                            const GDBusCXX::DBusObject_t &path,
                            const std::string &strLevel,
                            const std::string &explanation,
                            const std::string &procname)
 {
-    server.logOutput(path,
-                     Logger::strToLevel(strLevel.c_str()),
-                     explanation,
-                     procname);
+    static bool dbg = getenv("SYNCEVOLUTION_DEBUG");
+
+    if (dbg) {
+        // Print to D-Bus directly. The helper handles its own
+        // printing to the console.
+        server.logOutput(path,
+                         Logger::strToLevel(strLevel.c_str()),
+                         explanation,
+                         procname);
+    } else {
+        // Print to D-Bus and console, because the helper
+        // relies on us to do that. Its own stdout/stderr
+        // was redirected into our pipe and any output
+        // there is considered an error.
+        Logger::MessageOptions options(Logger::strToLevel(strLevel.c_str()));
+        options.m_processName = &procname;
+        Logging2ServerAndStdout(server, path, options, "%s", explanation.c_str());
+    }
 }
 
 void Session::useHelper2(const SimpleResult &result, const boost::signals2::connection &c)