gs.execute with stdin does not work properly

[maxfragg]

/usr/local/lib/python2.7/dist-packages/pyvbox-0.1->py2.7.egg/virtualbox/library_ext/guest_session.pyc in execute(self, command, >arguments, stdin, environment, flags, priority, affinity, timeout_ms) 59 while index < len(stdin): 60 index += process.write(0, [library.ProcessInputFlag.none], ---> 61 stdin[index:], 0) 62 process.write(0, [library.ProcessInputFlag.end_of_file], 0) 63

/usr/local/lib/python2.7/dist-packages/pyvbox-0.1-py2.7.egg/virtualbox/library.pyc in >write(self, handle, flags, data, timeout_ms) 13748 raise TypeError("handle can only be an instance of type baseinteger") 13749 if not isinstance(flags, baseinteger): 13750 raise TypeError("flags can only be an instance of type baseinteger") 13751 if not isinstance(data, list): 13752 raise TypeError("data can only be an instance of type list")

TypeError: flags can only be an instance of type baseinteger

i get this error, when ever trying to use execute with input.

calling process.write() manualy with 0 instead of [library.ProcessInputFlag.none] seams to work, but then i get a type error for the stdin, no matter what i put there, it really should be a string, right? I'm not really sure, but it looks like the error checks in the process.write() don't work properly. And the following process.write(0, [library.ProcessInputFlag.end_of_file], 0) will probably fail as well, since write takes exactly 5 arguments and omitting stdin will probably crash as well.

[maxfragg]

just to be sure, i use virtualbox 4.3.6, and run the git version fo pyvbox, all running on ubuntu 13.10

[mjdorma]

Good find... It's a bug in the xidl defining IProcess.write.

I'll build an extension to IProcess such that write will check for ProcessInputFlag.

Note: this is where the bug comes from: AMENDED: not 100% correct... Bug is a change in API

>>>>
        in flags of type int
            A combination of <link to="ProcessInputFlag"/> flags.
<<<<

Where the xidl should have (IProcess.write_array for reference):

>>>>
        in flags of type ProcessInputFlag
            A combination of <link to="ProcessInputFlag"/> flags.
<<<<

[maxfragg]

ah, so i understand, this bug comes form automatic generated code, which is based on the virtualbox com api? And should not

if not isinstance(data, list): raise TypeError("data can only be an instance of type list")

be

if not isinstance(data, str): raise TypeError("data can only be an instance of type str")

The docstring at least claims, that data should be a string ;-) Is it save, if i just try to fix those things for the moment in the autogenerated code, or would you sugguest, to wait for a propper fix form your side?

[mjdorma]

Yeah that's where it comes from. I just had a good look into this issue, it looks like the interfaces have been updated... I couldn't see a quick way of fixing it (big shame because I need to fix it).

Manually prodding the interface yielded fail as I was getting 0 bytes back when I wrote to the process (maybe I need to electrify my prodder...).

[mjdorma]

Links to this issue: https://www.virtualbox.org/pipermail/vbox-dev/2013-June/011556.html

[maxfragg]

thanks for the info, could you give me a hint, is the IProcess.write_array working as expected, and if so, how can i use it, to send input? i did not have any success, besides it returning the number of entries in the array. I understand it correctly, that the data-array should contain ascii codes for input data? My alternative would be using the session.console.keyboard.put_keys function, but that is racy and does not seam to be a good solution.

thx for any help in advance

[mjdorma]

If we can figure out how to manually drive vboxapi such that you can satisfy the IProcess.write(...) parameters and get a valid bytes written count return that will solve this issue.

Example:

gs = s.console.guest.create_session ... 
# Trying to do something like: gs.execute(r"C:\MinGW\msys\1.0\bin\grep.exe", ["z"], stdin="fooz")

p = gs.process_create_ex(r"C:\MinGW\msys\1.0\bin\grep.exe", ["z"], [], flags = [library.ProcessCreateFlag.wait_for_std_err, library.ProcessCreateFlag.wait_for_std_out, library.ProcessCreateFlag.ignore_orphaned_processes], priority=library.ProcessPriority.default, affinity=[], timeout_ms=0)

# You can invoke directly to the vboxapi (avoiding the checks).
# The following no longer works and raises an error saying it wants a sequence:
written = p._call("write", in_p=[0, 0, "foo", 0])
VBoxError: 0x-1 (Objects for SAFEARRAYS must be sequences (of sequences), or a buffer object.)

# Trying the following raises saying it was a base 10, which is strange because it is supposed to be (and used to be) a byte array:
written = p._call("write", in_p=[0, 0, "foo", 0])
VBoxError: 0x-1 (invalid literal for int() with base 10: 'f')

# Maybe you could get a win with write_array:
# process.write_array == p._call("writeArray", in_p=[ ....  etc etc

I have to leave this for a few days now. It would be great if you find a solution in the interim.

Cheers

[mjdorma]

Oh, you got write_array working? Did you get the number of bytes written to the process?

Pass me the code and I can update library_ext/guest_session.py

[maxfragg]

no i did not, calling it like that: process.write_array(0,[virtualbox.library.ProcessInputFlag.none],['64','0'],0) will return 2, but nothing will reach the process in the VM, at least not for the linux-vm I used. And no hurry with it, I can live without it for now, with enough waiting the raw keyboard input does the job i need, but its really not the best solution, as you might understand ;-)

[mjdorma]

For sure. The execute function supported stdin for good reason... This bug is the result of changes in the vbox API. For now I will just keep this bug opened. If you or anyone notices that the API is behaving correctly again (or find a solution) feel free to post me a hint.

Cheers

[sethmlarson]

I believe the API is working again so this issue can be closed.

[Smarre]

I do see this issue still, though...

password = "foo"
self.guest_session.execute("/usr/bin/passwd", arguments=["build"], stdin=password)

This fails with TypeError: data can only be an instance of type list, caused by execute() to pass a map instead of list to write_array() as data argument.

[mjdorma]

I do see this issue still, though...

password = "foo"
self.guest_session.execute("/usr/bin/passwd", arguments=["build"], stdin=password)

This fails with TypeError: data can only be an instance of type list, caused by execute() to pass a map instead of list to write_array() as data argument.

Try adding the password to a list. [password] ?

Assume your issue is @ https://github.com/sethmlarson/virtualbox-python/blob/d48da8a828fab8bafa425d8d859249ad7d752a50/virtualbox/library_ext/guest_session.py#L80

Process write_array : https://pythonhosted.org/pyvbox/virtualbox/library.html#virtualbox.library.IGuestProcess.write_array

... finally check the code gen for this interface

if not isinstance(data, list):
    raise TypeError("data can only be an instance of type list")

for a in data[:10]:
    if not isinstance(a, basestring):
        raise TypeError("array can only contain objects of ....

Failing that, you could test adding an override to the code generate interface for write_array under the guest process extension module? Force it to accept the string.

[Smarre]

Try adding the password to a list. [password] ?

Still gives the same error.

Failing that, you could test adding an override to the code generate interface for write_array under the guest process extension module? Force it to accept the string.

Well, forcing it to accept a string won’t help, since it won’t get a string, but a map. The execute() convenience method converts the input string to a map of unicode characters, where write() (and I suppose write_array(), though I’m not sure what’s the actual difference between the two) expects a list of unicode characters (which is what Virtualbox wants).

My guess is that changing the map to utilize a list would make this work better. I converted to use process_start() and am passing arguments in with slighty modified converter:

bytearray = [str(ord(char)) for char in password]

Though honestly, I’d rather be able to pass a stream instead, so I could just write whatever I’d need to. But that probably would need some threading logic.

[mjdorma]

Ha, that’s what I get for using a phone to read old code. Ok, that makes sense.

So the simple win is to wrap the map up with list() in the execute helper?

array = list(map(lambda a: str(ord(a)), stdin[index:]))

[Smarre]

Python is not my forte (using it for a work project out of necessity), so I can’t comment on what would be a good way to solve it. I used my version because it was simplest one I was able to figure out.