Eric Blake 63bfc59823 python: don't mask libvirt errors
A user reported this crash when using python bindings:

  File "/home/nox/workspace/NOX/src/NOX/hooks.py", line 134, in trigger
    hook.trigger(event)
  File "/home/nox/workspace/NOX/src/NOX/hooks.py", line 33, in trigger
    self.handlers[event]()
  File "/home/nox/workspace/NOX/hooks/volatility.py", line 81, in memory_dump
    for block in Memory(self.ctx):
  File "/home/see/workspace/NOX/src/NOX/lib/libtools.py", line 179, in next
    libvirt.VIR_MEMORY_PHYSICAL)
  File "/usr/lib/python2.7/dist-packages/libvirt.py", line 1759, in memoryPeek
    ret = libvirtmod.virDomainMemoryPeek(self._o, start, size, flags)
SystemError: error return without exception set

In the python bindings, returning NULL makes python think an
exception was thrown, while returning the None object lets the
wrappers know that a libvirt error exists.

Reported by Nox DaFox, fix suggested by Dan Berrange.

* python/libvirt-override.c (libvirt_virDomainBlockPeek)
(libvirt_virDomainMemoryPeek): Return python's None object, so
wrapper knows to check libvirt error.
2012-08-31 14:31:13 -07:00
..
2012-04-10 06:24:03 -04:00

    libvirt Python Bindings README
    ==============================

Most of the libvirt python binding code is automatically generated
using the script  generator.py, and the API description from
docs/libvirt-api.xml


Manually written files:

 - libvirt-override.c: methods where the C binding needs to be hand crafted
 - libvirt-override.py: global methods where the C and python bindings have different args
 - libvirt-override-api.xml: methods where the auto-extracted API docs are not
   suitable for python auto-generator. Overriding this if the method is going
   into libvirt-override.c, but we still want auto-generated libvirt-override.py
 - libvirt-override-virConnect.py: virConnect class methods
 - typewrappers.h,.c: Python object wrappers for each libvirt C object


Auto-generated files:

  - libvirt.py: The main python binding. Comprises auto-generated code, along
    with contents from libvirt-override.py and libvirt-override-virConnect.py
  - libvirt.c, libvirt.h: The C glue layer for the python binding. Comprises
    auto-generated code, along with libvirt-override.c
  - libvirt-export.c: List of auto-generated C methods, included into
    the libvirt-override.c method table