Qt Browser Plugins make the browser unresponsive

[David Morris]

Qt provides a solution for implementing browser plugins for web browsers which support the Netscape LiveConnect API. However the simple 'Hello World' example fails to run on Ubuntu 8.10 and Ubuntu 9.04. It simply hangs in both Firefox and Epiphany making the browser unresponsive.

Looking at the same code compiled and running on Ubuntu 8.04 (Hardy), Fedora 9 and Debian Lenny works. Therefore I believe it is Ubuntu specific problem introduced between 8.04 and 8.10.

The Qt site on the plugin is http://www.qtsoftware.com/products/appdev/add-on-products/catalog/4/Utilities/qtbrowserplugin

To test you need to download, build and install the open source version of the plugin. The install path for Firefox is /usr/lib/firefox/plugins/

Once installed, visiting the example page http://doc.trolltech.com/solutions/4/qtbrowserplugin/qtbrowserplugin-example-trivial.html will show the bug.

[Terence Simpson (tsimpson)]

I can not confirm this, when I compile the plugin and copy it to /usr/lib/mozilla/plugins/ the example page works as expected.
Are you running the plugin on the same system that compiled it?
If not, does the system have the Qt libraries installed (libqt4-gui)?
Is there any output from the command line when you run firefox from there?

[David Morris (dave-greenacre)]

I made a mistake before I've not tried it in Fedora 9 but in-fact Fedora 10

[David Morris (dave-greenacre)]

When launching via a terminal I get no messages about been unable to find libraries etc.

I've tried installing to the same path your using on both my i386 and x86_64 machines, with the same result. (Both are running up to date 9.04)

What version are you testing with?

Output of ldd is below in-case I'm linking against something different.

dave@cubert:~/checkouts/qtbrowserplugin-2.3-opensource$ ldd examples/trivial/libtrivial.so
 linux-vdso.so.1 => (0x00007fff625fe000)
 libQtGui.so.4 => /usr/lib/libQtGui.so.4 (0x00007f6a59561000)
 libQtCore.so.4 => /usr/lib/libQtCore.so.4 (0x00007f6a59114000)
 libpthread.so.0 => /lib/libpthread.so.0 (0x00007f6a58ef7000)
 libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0x00007f6a58bea000)
 libm.so.6 => /lib/libm.so.6 (0x00007f6a58965000)
 libgcc_s.so.1 => /lib/libgcc_s.so.1 (0x00007f6a5874c000)
 libc.so.6 => /lib/libc.so.6 (0x00007f6a583da000)
 libaudio.so.2 => /usr/lib/libaudio.so.2 (0x00007f6a581c1000)
 libpng12.so.0 => /usr/lib/libpng12.so.0 (0x00007f6a57f99000)
 libfreetype.so.6 => /usr/lib/libfreetype.so.6 (0x00007f6a57d13000)
 libgobject-2.0.so.0 => /usr/lib/libgobject-2.0.so.0 (0x00007f6a57acd000)
 libSM.so.6 => /usr/lib/libSM.so.6 (0x00007f6a578c3000)
 libICE.so.6 => /usr/lib/libICE.so.6 (0x00007f6a576a8000)
 libz.so.1 => /lib/libz.so.1 (0x00007f6a57490000)
 libglib-2.0.so.0 => /usr/lib/libglib-2.0.so.0 (0x00007f6a571ca000)
 libXrender.so.1 => /usr/lib/libXrender.so.1 (0x00007f6a56fc0000)
 libfontconfig.so.1 => /usr/lib/libfontconfig.so.1 (0x00007f6a56d8e000)
 libXext.so.6 => /usr/lib/libXext.so.6 (0x00007f6a56b7b000)
 libX11.so.6 => /usr/lib/libX11.so.6 (0x00007f6a56874000)
 libgthread-2.0.so.0 => /usr/lib/libgthread-2.0.so.0 (0x00007f6a5666f000)
 librt.so.1 => /lib/librt.so.1 (0x00007f6a56466000)
 libdl.so.2 => /lib/libdl.so.2 (0x00007f6a56262000)
 /lib64/ld-linux-x86-64.so.2 (0x00007f6a5a3e3000)
 libXt.so.6 => /usr/lib/libXt.so.6 (0x00007f6a55ffc000)
 libpcre.so.3 => /lib/libpcre.so.3 (0x00007f6a55dcb000)
 libuuid.so.1 => /lib/libuuid.so.1 (0x00007f6a55bc6000)
 libexpat.so.1 => /usr/lib/libexpat.so.1 (0x00007f6a5599b000)
 libXau.so.6 => /usr/lib/libXau.so.6 (0x00007f6a55798000)
 libxcb.so.1 => /usr/lib/libxcb.so.1 (0x00007f6a5557c000)
 libXdmcp.so.6 => /usr/lib/libXdmcp.so.6 (0x00007f6a55376000)

[David Morris (dave-greenacre)]

After speaking to Terence Simpson (who is using Kbuntu) I'm able to reproduce his success with the Kbuntu 9.04 liveCD. However I'm unable to do this on Ubuntu 9.04