Add a Mach-O decoder to the QPluginLoader

We already had an ELF decoder, which helped us greatly to find the
metadata and that catches most Unix systems (Solaris, QNX, HP-UXi, and
all of the free Unixes). On other Unix systems, aside from Mac OS X,
we simply scanned the entire file for the signature. On Windows, even
without a COFF-PE decoder, we use a LoadLibrary trick to load the
plugin without loading the dependent libraries. In most cases, that
works.

Unfortunately, on Mac OS X we didn't have a decoder and nor could we
do the file scan: because Mac OS X binaries could be fat binaries, we
wouldn't know which architecture's signature we had found.

No more. This adds a full Mach-O decoder to QtCore. It is also capable
of finding the boundaries of the architecture's binary, but that
functionality is disabled since all Qt 5 plugins have plugin metadata
sections.

Change-Id: I2d5c04c5ecf024864b8a43f31ab6b7e6c5eae9ce
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 25 insertions, 4 deletions

diff --git a/src/corelib/plugin/qlibrary.cpp b/src/corelib/plugin/qlibrary.cpp
index 3432f9619d..f015c3c236 100644
--- a/src/corelib/plugin/qlibrary.cpp
+++ b/src/corelib/plugin/qlibrary.cpp
@@ -1,7 +1,7 @@
-
 /****************************************************************************
 **
 ** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
+** Copyright (C) 2013 Intel Corporation
 ** Contact: http://www.qt-project.org/legal
 **
 ** This file is part of the QtCore module of the Qt Toolkit.
@@ -64,6 +64,7 @@
 #include <qjsondocument.h>
 #include <qjsonvalue.h>
 #include "qelfparser_p.h"
+#include "qmachparser_p.h"
 
 QT_BEGIN_NAMESPACE
 
@@ -180,7 +181,7 @@ QT_BEGIN_NAMESPACE
 */
 
 
-#if defined(Q_OS_UNIX) && !defined(Q_OS_MAC)
+#if defined(Q_OS_UNIX)
 
 static long qt_find_pattern(const char *s, ulong s_len,
                              const char *pattern, ulong p_len)
@@ -253,7 +254,7 @@ static bool qt_unix_query(const QString &library, QLibraryPrivate *lib)
     }
 
     /*
-       ELF binaries on GNU, have .qplugin sections.
+       ELF and Mach-O binaries with GCC have .qplugin sections.
     */
     bool hasMetaData = false;
     long pos = 0;
@@ -274,6 +275,26 @@ static bool qt_unix_query(const QString &library, QLibraryPrivate *lib)
             pos += rel;
         hasMetaData = true;
     }
+#elif defined (Q_OF_MACH_O)
+    {
+        QString errorString;
+        int r = QMachOParser::parse(filedata, fdlen, library, &errorString, &pos, &fdlen);
+        if (r == QMachOParser::NotSuitable) {
+            if (qt_debug_component())
+                qWarning("QMachOParser: %s", qPrintable(errorString));
+            if (lib)
+                lib->errorString = errorString;
+            return false;
+        }
+        // even if the metadata section was not found, the Mach-O parser will
+        // at least return the boundaries of the right architecture
+        long rel = qt_find_pattern(filedata + pos, fdlen, pattern, plen);
+        if (rel < 0)
+            pos = -1;
+        else
+            pos += rel;
+        hasMetaData = true;
+    }
 #else
     pos = qt_find_pattern(filedata, fdlen, pattern, plen);
     if (pos > 0)
@@ -690,7 +711,7 @@ void QLibraryPrivate::updatePluginState()
     }
 #endif
 
-#if defined(Q_OS_UNIX) && !defined(Q_OS_MAC)
+#if defined(Q_OS_UNIX)
     if (!pHnd) {
         // use unix shortcut to avoid loading the library
         success = qt_unix_query(fileName, this);