[lldb-dev] Native windows debugging support

[Zachary Turner]

I'm not sure why I didn't get the original email from Greg here (?)  I'm
only seeing this copied in Todd's response.

In any case, Windows' concept of a user id and group id is a Security
Identifier, as Todd mentioned (usually called a SID).  Generally though I
don't think it's necessary to pass around the SID, because the target can
figure out the SID given a username.

Still, it feels a little awkward having a single class store everything
that might be needed for any platform.  Normally I'd expect to use
polymorphic types in this scenario.  A NativeProcessLinux, for example,
could freely cast a UserId to a PosixUserId, and a NativeWindowsProcess
could cast a UserId to a WindowsUserId.

There's also the issue of command options, as I mentioned in the response
to Jim.  Basically, "platform process list" doesn't even need a -U option
on Windows.  Or maybe even a stronger statement, it shouldn't have a -U
option.  It's easy to come up with scenarios where platforms differ
significantly enough that the same set of options don't even make sense, or
where a certain platform provides sets of functionality not available on
other platforms.  For those cases, it would be nice for the debugger
commands to be tailored to that specific platform.

So maybe my first task should be to work on the command options system a
little bit to enable this type of abstraction.  Thoughts?


On Wed, Jul 2, 2014 at 3:44 PM, Todd Fiala <tfiala at google.com> wrote:

> We'll probably end up needing to support something like this:
> https://en.wikipedia.org/wiki/Security_Identifier
>
> Most of the access control on Windows ends up revolving around those.
>
>
> On Wed, Jul 2, 2014 at 3:37 PM, Greg Clayton <gclayton at apple.com> wrote:
>
>>
>> > On Jul 2, 2014, at 2:52 PM, Zachary Turner <zturner at google.com> wrote:
>> >
>> > I've started experimenting with adding support to LLDB for debugging
>> native Windows executables on Windows.  So windows host, windows target.
>>  I've done a few little cleanup tasks here and there and fixed some
>> low-hanging fruit, and I'd like to move onto something more meaty.
>> >
>> > I took a look at what it would take to get "platform process list" to
>> work.  The first thing I notice is that all of the Process info objects
>> contain the notion of a UID and GID, a concept which doesn't really exist
>> on Windows.  An analagous concept exists, but it's represented completely
>> differently.
>> >
>> > My question is: How best to abstract out this functionality?  I'm still
>> not totally clear on where I'm allowed to use platform specific types /
>> APIs and where it needs to be platform agnostic.  My first thought is to
>> remove UID and GID from the ProcessInfo class, and replace them with a
>> instance a "ProcessUserId" class, then provide a PosixProcessUserId and a
>> WindowsProcessUserId, which abstracts away the differences.
>> >
>> > Assuming this approach is logical, where is the best place for this
>> code to go?  Host or Target?
>> >
>> > Anything else I should be aware of?
>>
>> Can we just make a UserID class and GroupID class which contains both an
>> integer and a string (and anything else that is required) and use that?
>> What does windows have as far as UID and GID goes? Will strings suffice?
>> Does it need more? As you can tell we are very unix centric right now, but
>> we do want to abstract. So I would go the route of making a UserID and a
>> GroupID class, everyone uses these classes and these classes need to be
>> able to store everything that all of our classes require. My simple guess
>> would be:
>>
>> class UserID {
>>    std::string m_name;
>>    lldb::user_id_t m_identifier;
>> };
>>
>> Same for kind of thing for GroupID.
>>
>> Greg
>>
>>
>>
>> _______________________________________________
>> lldb-dev mailing list
>> lldb-dev at cs.uiuc.edu
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>>
>
>
>
> --
> Todd Fiala | Software Engineer |  tfiala at google.com |  650-943-3180
>
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