Load libpython globally on Linux distributions

src/global_libpython_loader.cpp

@@ -0,0 +1,74 @@
+
+/**
+ * PyOtherSide: Asynchronous Python 3 Bindings for Qt 5
+ * Copyright (c) 2013, Thomas Perl <m@thp.io>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+ * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+ * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+ * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+ * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+ * PERFORMANCE OF THIS SOFTWARE.
+ **/
+
+#include "global_libpython_loader.h"
+
+namespace GlobalLibPythonLoader {
+
+#ifdef __linux__
+
+#define _GNU_SOURCE
+#include <link.h>
+
+#include <stdio.h>
+#include <string.h>
+
+static int load_python_globally_callback(struct dl_phdr_info *info, size_t size, void *data)
+{
+    int major, minor;
+    char *basename = strrchr(info->dlpi_name, '/');
+    int *success = (int *)data;
+
+    if (basename != NULL) {
+        if (sscanf(basename, "/libpython%d.%d.so", &major, &minor) != 2) {
+            if (sscanf(basename, "/libpython%d.%dm.so", &major, &minor) != 2) {
+                return 0;
+            }
+        }
+
+        void *pylib = dlopen(info->dlpi_name, RTLD_GLOBAL | RTLD_NOW);
+        if (pylib != NULL) {
+            *success = 1;
+        } else {
+            fprintf(stderr, "Could not load python library '%s': %s\n",
+                    info->dlpi_name, dlerror());
+        }
+    }
+
+    return 0;
+}
+
+bool loadPythonGlobally()
+{
+    int success = 0;
+    dl_iterate_phdr(load_python_globally_callback, &success);
+    return success;
+}
+
+
+#else /* __linux__ */
+
+bool loadPythonGlobally()
+{
+    /* On non-Linux systems, no need to load globally */
+    return true;
+}
+
+#endif /* __linux__ */
+
+}; /* namespace GlobalLibPythonLoader */

src/global_libpython_loader.h

@@ -0,0 +1,26 @@
+
+/**
+ * PyOtherSide: Asynchronous Python 3 Bindings for Qt 5
+ * Copyright (c) 2013, Thomas Perl <m@thp.io>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+ * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+ * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+ * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+ * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+ * PERFORMANCE OF THIS SOFTWARE.
+ **/
+
+#ifndef PYOTHERSIDE_GLOBAL_LIBPYTHON_LOADER_H
+#define PYOTHERSIDE_GLOBAL_LIBPYTHON_LOADER_H
+
+namespace GlobalLibPythonLoader {
+    bool loadPythonGlobally();
+};
+
+#endif /* PYOTHERSIDE_GLOBAL_LIBPYTHON_LOADER_H */

src/pyotherside_plugin.cpp

@@ -19,6 +19,7 @@
 #include "qpython_priv.h"
 #include "qpython.h"
 #include "qpython_imageprovider.h"
+#include "global_libpython_loader.h"
 
 #include "pyotherside_plugin.h"
 
@@ -42,6 +43,13 @@ void
 PyOtherSideExtensionPlugin::initializeEngine(QQmlEngine *engine, const char *uri)
 {
     Q_ASSERT(QString(PYOTHERSIDE_PLUGIN_ID) == uri);
+
+    // In some Linux distributions, the plugin (and subsequently libpython)
+    // isn't loaded with the RTLD_GLOBAL flag, so symbols in libpython that
+    // are needed by shared Python modules won't be resolved unless we also
+    // load libpython again RTLD_GLOBAL again. We do this here.
+    GlobalLibPythonLoader::loadPythonGlobally();
+
     engine->addImageProvider(PYOTHERSIDE_IMAGEPROVIDER_ID, new QPythonImageProvider);
 }
 

src/src.pro

@@ -32,6 +32,10 @@ HEADERS += qpython_worker.h
 SOURCES += qpython_priv.cpp
 HEADERS += qpython_priv.h
 
+# Globally Load Python hack
+SOURCES += global_libpython_loader.cpp
+HEADERS += global_libpython_loader.h
+
 # Type System Conversion Logic
 HEADERS += converter.h
 HEADERS += qvariant_converter.h