Libxml2 has awful error reporting behaviour when reading files. When
we fail to load a file from the test driver we see:
$ virsh -c test:///wibble.xml
I/O warning : failed to load external entity "/wibble.xml"
error: failed to connect to the hypervisor
error: XML error: failed to parse xml document '/wibble.xml'
where the I/O warning line is something printed by libxml2 itself,
which also lacks any useful detail.
Switching to our own file reading code we can massively improve
things:
$ ./build/tools/virsh -c test:///wibble.xml
error: failed to connect to the hypervisor
error: Failed to open file '/wibble.xml': No such file or directory
Using 10 MB as an upper limit on XML file size ought to be sufficient
for any XML files libvirt is reading.
Reviewed-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
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