Merge remote-tracking branch 'origin/5.13' into dev

 Conflicts:
	qmake/generators/makefile.cpp
	qmake/generators/unix/unixmake2.cpp
	src/corelib/thread/qthread_unix.cpp
	tests/auto/corelib/tools/qsharedpointer/tst_qsharedpointer.cpp

Change-Id: I1df0d4ba20685de7f9300bf07458c13376493408

1 files changed, 38 insertions, 5 deletions

diff --git a/src/corelib/time/qtimezoneprivate_tz.cpp b/src/corelib/time/qtimezoneprivate_tz.cpp
index 2c845b1bce..1c74305e3d 100644
--- a/src/corelib/time/qtimezoneprivate_tz.cpp
+++ b/src/corelib/time/qtimezoneprivate_tz.cpp
@@ -50,6 +50,12 @@
 #include <qdebug.h>
 
 #include <algorithm>
+#include <errno.h>
+#include <limits.h>
+#if !defined(Q_OS_INTEGRITY)
+#include <sys/param.h> // to use MAXSYMLINKS constant
+#endif
+#include <unistd.h>    // to use _SC_SYMLOOP_MAX constant
 
 QT_BEGIN_NAMESPACE
 
@@ -1057,6 +1063,27 @@ QTimeZonePrivate::Data QTzTimeZonePrivate::previousTransition(qint64 beforeMSecs
     return last > m_tranTimes.cbegin() ? dataForTzTransition(*--last) : invalidData();
 }
 
+static long getSymloopMax()
+{
+#if defined(SYMLOOP_MAX)
+    return SYMLOOP_MAX; // if defined, at runtime it can only be greater than this, so this is a safe bet
+#else
+    errno = 0;
+    long result = sysconf(_SC_SYMLOOP_MAX);
+    if (result >= 0)
+        return result;
+    // result is -1, meaning either error or no limit
+    Q_ASSERT(!errno); // ... but it can't be an error, POSIX mandates _SC_SYMLOOP_MAX
+
+    // therefore we can make up our own limit
+#  if defined(MAXSYMLINKS)
+    return MAXSYMLINKS;
+#  else
+    return 8;
+#  endif
+#endif
+}
+
 // TODO Could cache the value and monitor the required files for any changes
 QByteArray QTzTimeZonePrivate::systemTimeZoneId() const
 {
@@ -1074,12 +1101,18 @@ QByteArray QTzTimeZonePrivate::systemTimeZoneId() const
 
     // On most distros /etc/localtime is a symlink to a real file so extract name from the path
     if (ianaId.isEmpty()) {
-        const QString path = QFile::symLinkTarget(QStringLiteral("/etc/localtime"));
-        if (!path.isEmpty()) {
+        const QLatin1String zoneinfo("/zoneinfo/");
+        QString path = QFile::symLinkTarget(QStringLiteral("/etc/localtime"));
+        int index = -1;
+        long iteration = getSymloopMax();
+        // Symlink may point to another symlink etc. before being under zoneinfo/
+        // We stop on the first path under /zoneinfo/, even if it is itself a
+        // symlink, like America/Montreal pointing to America/Toronto
+        while (iteration-- > 0 && !path.isEmpty() && (index = path.indexOf(zoneinfo)) < 0)
+            path = QFile::symLinkTarget(path);
+        if (index >= 0) {
             // /etc/localtime is a symlink to the current TZ file, so extract from path
-            int index = path.indexOf(QLatin1String("/zoneinfo/"));
-            if (index != -1)
-                ianaId = path.mid(index + 10).toUtf8();
+            ianaId = path.mid(index + zoneinfo.size()).toUtf8();
         }
     }