Libguestfs - Oct 2015 - Re: [nbdkit] can't import mmap

Hi,

I'm new to nbdkit and am trying to run a simple "single file block
device using mmap" setup, using this python script:

import mmap

def config(key, value):
    print ("ignored parameter %s=%s" % (key, value))

def open(readonly):
    print ("open: readonly=%d" % readonly)
    f = open("disk","r+")
    m = mmap.mmap(f.fileno(), 0, access=mmap.ACCESS_WRITE)
    return (f,m)

def get_size(h):
    size = 1024*1024

def pread(h, count, offset):
    (f,m) = h
    bytes = bytearray(m[offset:offset+count])
    return bytes

def pwrite(h, buf, offset):
    (f,m) = h
    m[offset:offset+len(buf)] = bytearray(buf)


When I run this:

/usr/sbin/nbdkit -f -v python script=single_file.py


I get this error:

nbdkit: debug: registering
/usr/lib/x86_64-linux-gnu/nbdkit/plugins/nbdkit-python-plugin.so
nbdkit: debug: registered
/usr/lib/x86_64-linux-gnu/nbdkit/plugins/nbdkit-python-plugin.so (name
python)
nbdkit: debug: /usr/lib/x86_64-linux-gnu/nbdkit/plugins/nbdkit-python-plugin.so:
load
nbdkit: debug: /usr/lib/x86_64-linux-gnu/nbdkit/plugins/nbdkit-python-plugin.so:
config key=script, value=single_file.py
Traceback (most recent call last):
  File "single_file.py", line 1, in <module>
    import mmap
ImportError: /usr/lib/python2.7/lib-dynload/mmap.x86_64-linux-gnu.so:
undefined symbol: PyExc_SystemError
nbdkit: error: single_file.py: error running this script


Any ideas?

Thanks,
Jason Pepas

On Thu, Oct 29, 2015 at 09:19:03AM -0500, Jason Pepas
wrote:
> Hi,
> 
> I'm new to nbdkit and am trying to run a simple "single file block
> device using mmap" setup, using this python script:
> 
> import mmap
> 
> def config(key, value):
>     print ("ignored parameter %s=%s" % (key, value))
> 
> def open(readonly):
>     print ("open: readonly=%d" % readonly)
>     f = open("disk","r+")
>     m = mmap.mmap(f.fileno(), 0, access=mmap.ACCESS_WRITE)
>     return (f,m)
> 
> def get_size(h):
>     size = 1024*1024
> 
> def pread(h, count, offset):
>     (f,m) = h
>     bytes = bytearray(m[offset:offset+count])
>     return bytes
> 
> def pwrite(h, buf, offset):
>     (f,m) = h
>     m[offset:offset+len(buf)] = bytearray(buf)
> 
> 
> When I run this:
> 
> /usr/sbin/nbdkit -f -v python script=single_file.py
> 
> 
> I get this error:
> 
> nbdkit: debug: registering
> /usr/lib/x86_64-linux-gnu/nbdkit/plugins/nbdkit-python-plugin.so
> nbdkit: debug: registered
> /usr/lib/x86_64-linux-gnu/nbdkit/plugins/nbdkit-python-plugin.so (name
> python)
> nbdkit: debug:
/usr/lib/x86_64-linux-gnu/nbdkit/plugins/nbdkit-python-plugin.so:
> load
> nbdkit: debug:
/usr/lib/x86_64-linux-gnu/nbdkit/plugins/nbdkit-python-plugin.so:
> config key=script, value=single_file.py
> Traceback (most recent call last):
>   File "single_file.py", line 1, in <module>
>     import mmap
> ImportError: /usr/lib/python2.7/lib-dynload/mmap.x86_64-linux-gnu.so:
> undefined symbol: PyExc_SystemError
> nbdkit: error: single_file.py: error running this script
> 
> 
> Any ideas?
It's probably this bug:

https://bugzilla.redhat.com/1223870

Fixed in this commit:

https://github.com/libguestfs/nbdkit/commit/77f4982e65840b6edff5e97d3dbdf140f7e3229b

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
libguestfs lets you edit virtual machines.  Supports shell scripting,
bindings from many languages.  http://libguestfs.org

Thanks!

Sent from my iPhone
> On Oct 29, 2015, at 9:55 AM, Richard W.M. Jones <rjones@redhat.com>
wrote:
> 
>> On Thu, Oct 29, 2015 at 09:19:03AM -0500, Jason Pepas wrote:
>> Hi,
>> 
>> I'm new to nbdkit and am trying to run a simple "single file
block
>> device using mmap" setup, using this python script:
>> 
>> import mmap
>> 
>> def config(key, value):
>>    print ("ignored parameter %s=%s" % (key, value))
>> 
>> def open(readonly):
>>    print ("open: readonly=%d" % readonly)
>>    f = open("disk","r+")
>>    m = mmap.mmap(f.fileno(), 0, access=mmap.ACCESS_WRITE)
>>    return (f,m)
>> 
>> def get_size(h):
>>    size = 1024*1024
>> 
>> def pread(h, count, offset):
>>    (f,m) = h
>>    bytes = bytearray(m[offset:offset+count])
>>    return bytes
>> 
>> def pwrite(h, buf, offset):
>>    (f,m) = h
>>    m[offset:offset+len(buf)] = bytearray(buf)
>> 
>> 
>> When I run this:
>> 
>> /usr/sbin/nbdkit -f -v python script=single_file.py
>> 
>> 
>> I get this error:
>> 
>> nbdkit: debug: registering
>> /usr/lib/x86_64-linux-gnu/nbdkit/plugins/nbdkit-python-plugin.so
>> nbdkit: debug: registered
>> /usr/lib/x86_64-linux-gnu/nbdkit/plugins/nbdkit-python-plugin.so (name
>> python)
>> nbdkit: debug:
/usr/lib/x86_64-linux-gnu/nbdkit/plugins/nbdkit-python-plugin.so:
>> load
>> nbdkit: debug:
/usr/lib/x86_64-linux-gnu/nbdkit/plugins/nbdkit-python-plugin.so:
>> config key=script, value=single_file.py
>> Traceback (most recent call last):
>>  File "single_file.py", line 1, in <module>
>>    import mmap
>> ImportError: /usr/lib/python2.7/lib-dynload/mmap.x86_64-linux-gnu.so:
>> undefined symbol: PyExc_SystemError
>> nbdkit: error: single_file.py: error running this script
>> 
>> 
>> Any ideas?
> 
> It's probably this bug:
> 
> https://bugzilla.redhat.com/1223870
> 
> Fixed in this commit:
> 
>
https://github.com/libguestfs/nbdkit/commit/77f4982e65840b6edff5e97d3dbdf140f7e3229b
> 
> Rich.
> 
> -- 
> Richard Jones, Virtualization Group, Red Hat
http://people.redhat.com/~rjones
> Read my programming and virtualization blog: http://rwmj.wordpress.com
> libguestfs lets you edit virtual machines.  Supports shell scripting,
> bindings from many languages.  http://libguestfs.org