tst_QFile: extend moveToTrash tests to exercise more corner cases

Added moveToTrashDuplicateName() to see what happens if you attempt to
trash two files with the same exact full path. Both files should get
independently moved to the trash bin and not clobber each other.

Added moveToTrashXdgSafety() to test that QFileSystemEngine will
properly skip over an unsafe $root/.Trash directory, as required by the
XDG specification. I think the specification should also make security
requirements on $root/.Trash-$uid too, but that's for another change.

Pick-to: 6.6
Change-Id: I9d43e5b91eb142d6945cfffd1786cd60e4244c7c
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

tests/auto/corelib/io/qfile/tst_qfile.cpp

@@ -288,8 +288,10 @@ private slots:
 
     void moveToTrash_data();
     void moveToTrash();
+    void moveToTrashDuplicateName();
     void moveToTrashOpenFile_data();
     void moveToTrashOpenFile();
+    void moveToTrashXdgSafety();
 
     void stdfilesystem();
 
@@ -4081,6 +4083,41 @@ void tst_QFile::moveToTrash()
     }
 }
 
+void tst_QFile::moveToTrashDuplicateName()
+{
+#if defined(Q_OS_ANDROID) || defined(Q_OS_WEBOS)
+    QSKIP("This platform doesn't implement a trash bin");
+#endif
+    QString origFileName = []() {
+        QTemporaryFile temp(QDir::homePath() + "/tst_qfile.moveToTrashOpenFile.XXXXXX");
+        temp.setAutoRemove(false);
+        if (!temp.open())
+            qWarning("Failed to create temporary file: %ls", qUtf16Printable(temp.errorString()));
+        return temp.fileName();
+    }();
+
+    QFile f1(origFileName);
+    QFile f2(origFileName);
+    [&] {
+        QByteArrayView message1 = "Hello, World\n";
+        QVERIFY2(f1.open(QIODevice::ReadWrite | QIODevice::Unbuffered), qPrintable(f1.errorString()));
+        f1.write(message1.data(), message1.size());
+        QVERIFY2(f1.moveToTrash(), qPrintable(f1.errorString()));
+
+        QByteArrayView message2 = "Good morning, Vietnam!\n";
+        QVERIFY2(f2.open(QIODevice::ReadWrite | QIODevice::Unbuffered | QIODevice::NewOnly),
+                 qPrintable(f2.errorString()));
+        f2.write(message2.data(), message2.size());
+        QVERIFY2(f2.moveToTrash(), qPrintable(f2.errorString()));
+
+        QCOMPARE_NE(f1.fileName(), f2.fileName());
+    }();
+    f1.remove();
+    if (!f2.fileName().isEmpty())
+        f2.remove();
+    QFile::remove(origFileName);
+}
+
 void tst_QFile::moveToTrashOpenFile_data()
 {
     QTest::addColumn<bool>("useStatic");
@@ -4161,6 +4198,79 @@ void tst_QFile::moveToTrashOpenFile()
     }
 }
 
+void tst_QFile::moveToTrashXdgSafety()
+{
+#if defined(Q_OS_WIN) || defined(Q_OS_DARWIN) || defined(Q_OS_ANDROID) || defined(Q_OS_WEBOS)
+    QSKIP("This test is specific to XDG Unix systems");
+#else
+    QDir(m_temporaryDir.path()).mkdir("emptydir");
+
+    // See if we can find a writable volume to conduct our tests on
+    QString volumeRoot;
+    QStorageInfo homeVolume(QDir::homePath());
+    auto isVolumeSuitable = [this](const QString &rootPath) {
+        return QFile::link(m_temporaryDir.path() + "/emptydir", rootPath + "/.Trash");
+    };
+    for (const QStorageInfo &volume : QStorageInfo::mountedVolumes()) {
+        if (volume.isRoot())
+            continue;
+        if (volume == homeVolume)
+            continue;
+
+        if (isVolumeSuitable(volume.rootPath())) {
+            volumeRoot = volume.rootPath();
+            break;
+        }
+    }
+
+#  ifdef Q_OS_LINUX
+    // fallback to /dev/shm, which is usually a tmpfs but is ignored by
+    // QStorageInfo as a virtual filesystem
+    if (volumeRoot.isEmpty() && isVolumeSuitable("/dev/shm"))
+        volumeRoot = "/dev/shm";
+#  endif
+
+    if (volumeRoot.isEmpty())
+        QSKIP("Could not find any suitable volume to run this test with");
+
+    QDir genericTrashDir = volumeRoot + "/.Trash";
+    auto cleanup = qScopeGuard([&] {
+        if (QFileInfo(genericTrashDir.path()).isDir())
+            genericTrashDir.removeRecursively();
+        else
+            QFile::remove(genericTrashDir.path());
+    });
+
+    QString testFileName = volumeRoot + "/tst_qfile.moveToTrashSafety." + QString::number(getpid());
+    auto tryTrashing = [&] {
+        static int counter = 0;
+        QFile f(testFileName + u'.' + QString::number(counter++));
+        if (!f.open(QIODevice::ReadWrite | QIODevice::Truncate)) {
+            qWarning("Failed to create temporary file: %ls", qUtf16Printable(f.errorString()));
+            return false;
+        }
+        bool ok = f.moveToTrash();
+        f.remove();
+        f.close();
+        return ok;
+    };
+
+    QTest::ignoreMessage(QtCriticalMsg,
+                         "Warning: '" + QFile::encodeName(genericTrashDir.absolutePath())
+                         + "' is a symlink to '" + QFile::encodeName(m_temporaryDir.path())
+                         + "/emptydir'");
+    QVERIFY(tryTrashing());
+    QVERIFY(genericTrashDir.entryList(QDir::NoDotAndDotDot).isEmpty());
+
+    QFile::remove(genericTrashDir.path());
+    genericTrashDir.mkpath(".");
+    QTest::ignoreMessage(QtCriticalMsg, "Warning: '" + QFile::encodeName(genericTrashDir.absolutePath())
+                         + "' doesn't have sticky bit set!");
+    QVERIFY(tryTrashing());
+    QVERIFY(genericTrashDir.entryList(QDir::NoDotAndDotDot).isEmpty());
+#endif
+}
+
 void tst_QFile::stdfilesystem()
 {
 #if QT_CONFIG(cxx17_filesystem)