QProcess::startDetached: support custom process environment

Starting a detached process with a custom process environment can now be
achieved by:

    QProcess p;
    p.setProgram("foo");
    p.setProcessEnvironment(myEnv);
    p.startDetached();

[ChangeLog][QtCore][QProcess] Added the ability to set a custom process
environment for detached processes.

Task-number: QTBUG-2284
Change-Id: I49406dffb64fa2aed41ea05cb271bd42eeabb729
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/io/qprocess_unix.cpp

@@ -937,6 +937,14 @@ bool QProcessPrivate::startDetached(qint64 *pid)
                 argv[i + 1] = ::strdup(QFile::encodeName(arguments.at(i)).constData());
             argv[arguments.size() + 1] = 0;
 
+            // Duplicate the environment.
+            int envc = 0;
+            char **envp = nullptr;
+            if (environment.d.constData()) {
+                QProcessEnvironmentPrivate::MutexLocker locker(environment.d);
+                envp = _q_dupEnvironment(environment.d.constData()->hash, &envc);
+            }
+
             QByteArray tmp;
             if (!program.contains(QLatin1Char('/'))) {
                 const QString &exeFilePath = QStandardPaths::findExecutable(program);
@@ -946,7 +954,11 @@ bool QProcessPrivate::startDetached(qint64 *pid)
             if (tmp.isEmpty())
                 tmp = QFile::encodeName(program);
             argv[0] = tmp.data();
-            qt_safe_execv(argv[0], argv);
+
+            if (envp)
+                qt_safe_execve(argv[0], argv, envp);
+            else
+                qt_safe_execv(argv[0], argv);
 
             struct sigaction noaction;
             memset(&noaction, 0, sizeof(noaction));

src/corelib/io/qprocess_win.cpp

@@ -867,6 +867,13 @@ bool QProcessPrivate::startDetached(qint64 *pid)
     bool success = false;
     PROCESS_INFORMATION pinfo;
 
+    void *envPtr = nullptr;
+    QByteArray envlist;
+    if (environment.d.constData()) {
+        envlist = qt_create_environment(environment.d.constData()->hash);
+        envPtr = envlist.data();
+    }
+
     DWORD dwCreationFlags = (GetConsoleWindow() ? 0 : CREATE_NO_WINDOW);
     dwCreationFlags |= CREATE_UNICODE_ENVIRONMENT;
     STARTUPINFOW startupInfo = { sizeof( STARTUPINFO ), 0, 0, 0,
@@ -875,7 +882,7 @@ bool QProcessPrivate::startDetached(qint64 *pid)
                                  0, 0, 0, 0, 0, 0, 0, 0, 0, 0
                                };
     success = CreateProcess(0, (wchar_t*)args.utf16(),
-                            0, 0, FALSE, dwCreationFlags, 0,
+                            0, 0, FALSE, dwCreationFlags, envPtr,
                             workingDirectory.isEmpty() ? 0 : (wchar_t*)workingDirectory.utf16(),
                             &startupInfo, &pinfo);
 
@@ -885,6 +892,8 @@ bool QProcessPrivate::startDetached(qint64 *pid)
         if (pid)
             *pid = pinfo.dwProcessId;
     } else if (GetLastError() == errorElevationRequired) {
+        if (envPtr)
+            qWarning("QProcess: custom environment will be ignored for detached elevated process.");
         success = startDetachedUacPrompt(program, arguments, workingDirectory, pid);
     }
 

tests/auto/corelib/io/qprocess/testDetached/main.cpp

@@ -65,6 +65,8 @@ int main(int argc, char **argv)
     f.write(QByteArray::number(quint64(GetCurrentProcessId())));
 #endif
     f.putChar('\n');
+    f.write(qgetenv("tst_QProcess"));
+    f.putChar('\n');
 
     f.close();
 

tests/auto/corelib/io/qprocess/tst_qprocess.cpp

@@ -126,7 +126,7 @@ private slots:
     void systemEnvironment();
     void lockupsInStartDetached();
     void waitForReadyReadForNonexistantProcess();
-    void detachedWorkingDirectoryAndPid();
+    void detachedProcessParameters();
     void startFinishStartFinish();
     void invalidProgramString_data();
     void invalidProgramString();
@@ -2030,7 +2030,7 @@ void tst_QProcess::fileWriterProcess()
     } while (stopWatch.elapsed() < 3000);
 }
 
-void tst_QProcess::detachedWorkingDirectoryAndPid()
+void tst_QProcess::detachedProcessParameters()
 {
     qint64 pid;
 
@@ -2042,9 +2042,17 @@ void tst_QProcess::detachedWorkingDirectoryAndPid()
 
     QVERIFY(QFile::exists(workingDir));
 
-    QStringList args;
+    QVERIFY(qgetenv("tst_QProcess").isEmpty());
-    args << infoFile.fileName();
+    QByteArray envVarValue("foobarbaz");
-    QVERIFY(QProcess::startDetached(QDir::currentPath() + QLatin1String("/testDetached/testDetached"), args, workingDir, &pid));
+    QProcessEnvironment environment = QProcessEnvironment::systemEnvironment();
+    environment.insert(QStringLiteral("tst_QProcess"), QString::fromUtf8(envVarValue));
+
+    QProcess process;
+    process.setProgram(QDir::currentPath() + QLatin1String("/testDetached/testDetached"));
+    process.setArguments(QStringList(infoFile.fileName()));
+    process.setWorkingDirectory(workingDir);
+    process.setProcessEnvironment(environment);
+    QVERIFY(process.startDetached(&pid));
 
     QFileInfo fi(infoFile);
     fi.setCaching(false);
@@ -2055,10 +2063,9 @@ void tst_QProcess::detachedWorkingDirectoryAndPid()
     }
 
     QVERIFY(infoFile.open(QIODevice::ReadOnly | QIODevice::Text));
-    QString actualWorkingDir = QString::fromUtf8(infoFile.readLine());
+    QString actualWorkingDir = QString::fromUtf8(infoFile.readLine()).trimmed();
-    actualWorkingDir.chop(1); // strip off newline
+    QByteArray processIdString = infoFile.readLine().trimmed();
-    QByteArray processIdString = infoFile.readLine();
+    QByteArray actualEnvVarValue = infoFile.readLine().trimmed();
-    processIdString.chop(1);
     infoFile.close();
     infoFile.remove();
 
@@ -2068,6 +2075,7 @@ void tst_QProcess::detachedWorkingDirectoryAndPid()
 
     QCOMPARE(actualWorkingDir, workingDir);
     QCOMPARE(actualPid, pid);
+    QCOMPARE(actualEnvVarValue, envVarValue);
 }
 
 void tst_QProcess::switchReadChannels()