On Wed, Jul 17, 2019 at 13:33:08 -0500, Probir Roy wrote:
Hi,
I am trying to preload two shared libraries while running Qemu using libvirt. To preload the shared libraries I have added an environment variable in the $domain.xml file with the following command:
``` virt-xml generic --edit --confirm --qemu-commandline 'env=LD_PRELOAD=/home/probir/Downloads/kpv_temp/temp/kvmTest/build_kvm/libperform.so:/home/probir/Downloads/kpv_temp/temp/kvmTest/dependencies/libmonitor/installDir/lib/libmonitor.so'
``` However, while running the domain, I get the following message of failure to preload the shared files in the log.
``` 2019-07-17 17:35:22.939+0000: starting up libvirt version: 1.3.1, package: 1ubuntu10.27 (Marc Deslauriers <marc.deslauriers@ubuntu.com> Tue, 02 Jul 2019 09:22:37 -0400), qemu version: 2.5.0 (Debian 1:2.5+dfsg-5ubuntu10.39), hostname: probir-XPS-13-9343 LC_ALL=C PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin QEMU_AUDIO_DRV=spice LD_PRELOAD=/home/probir/Downloads/kpv_temp/temp/kvmTest/build_kvm/libperform.so:/home/probir/Downloads/kpv_temp/temp/kvmTest/dependencies/libmonitor/installDir/lib/libmonitor.so /usr/bin/kvm-spice -name generic -S -machine
[...]
ERROR: ld.so: object '/home/probir/Downloads/kpv_temp/temp/kvmTest/build_kvm/libperform.so' from LD_PRELOAD cannot be preloaded (cannot open shared object file): ignored. ERROR: ld.so: object '/home/probir/Downloads/kpv_temp/temp/kvmTest/dependencies/libmonitor/installDir/lib/libmonitor.so' from LD_PRELOAD cannot be preloaded (cannot open shared object file): ignored.
My rough guess would be that the process we forked off for qemu has security confinment applied (apparmor and unix permissions changed in case of ubuntu) and ld.so is thus unable to open the libraries you want it to preload. For any other resource libvirt configures the confinment such as that the process has access, but in this case this is out of our scope and you have to make sure that the libs are accessible yourself.