• Max Reitz's avatar
    block/file-*: *_parse_filename() and colons · 03c320d8
    Max Reitz authored
    The file drivers' *_parse_filename() implementations just strip the
    optional protocol prefix off the filename. However, for e.g.
    "file:foo:bar", this would lead to "foo:bar" being stored as the BDS's
    filename which looks like it should be managed using the "foo" protocol.
    This is especially troublesome if you then try to resolve a backing
    filename based on "foo:bar".
    
    This issue can only occur if the stripped part is a relative filename
    ("file:/foo:bar" will be shortened to "/foo:bar" and having a slash
    before the first colon means that "/foo" is not recognized as a protocol
    part). Therefore, we can easily fix it by prepending "./" to such
    filenames.
    
    Before this patch:
    $ ./qemu-img create -f qcow2 backing.qcow2 64M
    Formatting 'backing.qcow2', fmt=qcow2 size=67108864 encryption=off
        cluster_size=65536 lazy_refcounts=off refcount_bits=16
    $ ./qemu-img create -f qcow2 -b backing.qcow2 file:top:image.qcow2
    Formatting 'file:top:image.qcow2', fmt=qcow2 size=67108864
        backing_file=backing.qcow2 encryption=off cluster_size=65536
        lazy_refcounts=off refcount_bits=16
    $ ./qemu-io file:top:image.qcow2
    can't open device file:top:image.qcow2: Could not open backing file:
        Unknown protocol 'top'
    
    After this patch:
    $ ./qemu-io file:top:image.qcow2
    [no error]
    Signed-off-by: 's avatarMax Reitz <mreitz@redhat.com>
    Message-id: 20170522195217.12991-3-mreitz@redhat.com
    Reviewed-by: 's avatarEric Blake <eblake@redhat.com>
    Signed-off-by: 's avatarMax Reitz <mreitz@redhat.com>
    03c320d8
block.c 143 KB