Fix literal IPv6 hostname resolution in QHostInfo.

With the series of commits ending in ff1280178, I made QUrl::toAce
fail if the parameter is not a well-formed hostname (i.e., if it
violates STD3). IPv6 hostnames do, so we can't preemptively run
ToACE.

Instead, delay running ToACE until we've tried literal matching.

Reviewed-by: TrustMe

3 files changed, 40 insertions, 19 deletions

diff --git a/src/network/kernel/qhostinfo.cpp b/src/network/kernel/qhostinfo.cpp
index ee1369d..77b2a7e 100644
--- a/src/network/kernel/qhostinfo.cpp
+++ b/src/network/kernel/qhostinfo.cpp
@@ -162,16 +162,13 @@ int QHostInfo::lookupHost(const QString &name, QObject *receiver,
     QWindowsSockInit bust; // makes sure WSAStartup was callled
 #endif
 
-    // Support for IDNA
-    QString lookup = QString::fromLatin1(QUrl::toAce(name));
-
     QHostInfoResult *result = new QHostInfoResult;
     result->autoDelete = false;
     QObject::connect(result, SIGNAL(resultsReady(QHostInfo)),
                      receiver, member);
     int id = result->lookupId = theIdCounter.fetchAndAddRelaxed(1);
 
-    if (lookup.isEmpty()) {
+    if (name.isEmpty()) {
         QHostInfo info(id);
         info.setError(QHostInfo::HostNotFound);
         info.setErrorString(QObject::tr("No host name given"));
@@ -182,7 +179,7 @@ int QHostInfo::lookupHost(const QString &name, QObject *receiver,
     }
 
     QHostInfoAgent *agent = theAgent();
-    agent->addHostName(lookup, result);
+    agent->addHostName(name, result);
 
 #if !defined QT_NO_THREAD
     if (!agent->isRunning())
@@ -226,13 +223,7 @@ QHostInfo QHostInfo::fromName(const QString &name)
     qDebug("QHostInfo::fromName(\"%s\")",name.toLatin1().constData());
 #endif
 
-    if (!name.isEmpty())
-        return QHostInfoAgent::fromName(QLatin1String(QUrl::toAce(name)));
-
-    QHostInfo retval;
-    retval.d->err = HostNotFound;
-    retval.d->errorStr = QObject::tr("No host name given");
-    return retval;
+    return QHostInfoAgent::fromName(name);
 }
 
 /*!
diff --git a/src/network/kernel/qhostinfo_unix.cpp b/src/network/kernel/qhostinfo_unix.cpp
index 4a23399..e3d51e7 100644
--- a/src/network/kernel/qhostinfo_unix.cpp
+++ b/src/network/kernel/qhostinfo_unix.cpp
@@ -124,7 +124,6 @@ static void resolveLibrary()
 QHostInfo QHostInfoAgent::fromName(const QString &hostName)
 {
     QHostInfo results;
-    results.setHostName(hostName);
 
 #if defined(QHOSTINFO_DEBUG)
     qDebug("QHostInfoAgent::fromName(%s) looking up...",
@@ -194,6 +193,22 @@ QHostInfo QHostInfoAgent::fromName(const QString &hostName)
 #endif
     }
 
+    // IDN support
+    QByteArray aceHostname;
+    if (results.hostName().isEmpty()) {
+        // it's a hostname resolution
+        aceHostname = QUrl::toAce(hostName);
+        results.setHostName(hostName);
+        if (aceHostname.isEmpty()) {
+            results.setError(QHostInfo::HostNotFound);
+            results.setErrorString(hostName.isEmpty() ? QObject::tr("No host name given") : QObject::tr("Invalid hostname"));
+            return results;
+        }
+    } else {
+        // it's an IP reverse resolution
+        aceHostname = results.hostName().toLatin1();
+    }
+
 #if !defined (QT_NO_GETADDRINFO)
     // Call getaddrinfo, and place all IPv4 addresses at the start and
     // the IPv6 addresses at the end of the address list in results.
@@ -205,12 +220,12 @@ QHostInfo QHostInfoAgent::fromName(const QString &hostName)
     hints.ai_flags = Q_ADDRCONFIG;
 #endif
 
-    int result = getaddrinfo(hostName.toLatin1().constData(), 0, &hints, &res);
+    int result = getaddrinfo(aceHostname.constData(), 0, &hints, &res);
 # ifdef Q_ADDRCONFIG
     if (result == EAI_BADFLAGS) {
         // if the lookup failed with AI_ADDRCONFIG set, try again without it
         hints.ai_flags = 0;
-        result = getaddrinfo(hostName.toLatin1().constData(), 0, &hints, &res);
+        result = getaddrinfo(aceHostname.constData(), 0, &hints, &res);
     }
 # endif
 
@@ -264,7 +279,7 @@ QHostInfo QHostInfoAgent::fromName(const QString &hostName)
     // use one QHostInfoAgent, but if more agents are introduced, locking
     // must be provided.
     QMutexLocker locker(::getHostByNameMutex());
-    hostent *result = gethostbyname(hostName.toLatin1().constData());
+    hostent *result = gethostbyname(aceHostname.constData());
     if (result) {
         if (result->h_addrtype == AF_INET) {
             QList<QHostAddress> addresses;
diff --git a/src/network/kernel/qhostinfo_win.cpp b/src/network/kernel/qhostinfo_win.cpp
index 93dc720..8fd3a3f 100644
--- a/src/network/kernel/qhostinfo_win.cpp
+++ b/src/network/kernel/qhostinfo_win.cpp
@@ -129,7 +129,6 @@ QHostInfo QHostInfoAgent::fromName(const QString &hostName)
     }
 
     QHostInfo results;
-    results.setHostName(hostName);
 
 #if defined(QHOSTINFO_DEBUG)
     qDebug("QHostInfoAgent::fromName(%p): looking up \"%s\" (IPv6 support is %s)",
@@ -178,12 +177,28 @@ QHostInfo QHostInfoAgent::fromName(const QString &hostName)
         }
     }
 
+    // IDN support
+    QByteArray aceHostname;
+    if (results.hostName().isEmpty()) {
+        // it's a hostname resolution
+        aceHostname = QUrl::toAce(hostName);
+        results.setHostName(hostName);
+        if (aceHostname.isEmpty()) {
+            results.setError(QHostInfo::HostNotFound);
+            results.setErrorString(hostName.isEmpty() ? QObject::tr("No host name given") : QObject::tr("Invalid hostname"));
+            return results;
+        }
+    } else {
+        // it's an IP reverse resolution
+        aceHostname = results.hostName().toLatin1();
+    }
+
     if (local_getaddrinfo && local_freeaddrinfo) {
         // Call getaddrinfo, and place all IPv4 addresses at the start
         // and the IPv6 addresses at the end of the address list in
         // results.
         qt_addrinfo *res;
-        int err = local_getaddrinfo(hostName.toLatin1().constData(), 0, 0, &res);
+        int err = local_getaddrinfo(aceHostname.constData(), 0, 0, &res);
         if (err == 0) {
             QList<QHostAddress> addresses;
             for (qt_addrinfo *p = res; p != 0; p = p->ai_next) {
@@ -218,7 +233,7 @@ QHostInfo QHostInfoAgent::fromName(const QString &hostName)
         }
     } else {
         // Fall back to gethostbyname, which only supports IPv4.
-        hostent *ent = gethostbyname(hostName.toLatin1().constData());
+        hostent *ent = gethostbyname(aceHostname.constData());
         if (ent) {
             char **p;
             QList<QHostAddress> addresses;