2018-03-09 16:47 GMT+01:00 Alistair Grant <akgrant0...@gmail.com>:
> Hi Pavel,
>
> On 9 March 2018 at 16:12, Pavel Krivanek <pavel.kriva...@gmail.com> wrote:
>> 2018-03-09 16:02 GMT+01:00 Alistair Grant <akgrant0...@gmail.com>:
>>> Hi Pavel,
>>>
>>> I tried to get this working on Ubuntu 16.04 and found the following:
>>>
>>> - The compilation failed unless I added the '-fPIC' flag (as suggested by
>>> gcc).
>>
>> is it on 64-bit system and VM?
>
> Yep.
I will check that, I guess some package is missing in this Ubuntu
environment because I think I checked it on the same system without
this issue.
>
>
>>> - The example code in the TerminalEmulator class comment references
>>> ProcessEndpoint, but the class doesn't exist.
>>
>> Thanks, this class was renamed
>
> To PseudoTTYEndpoint, it looks like.
>
> Cool! The interactive terminal is up and running.
>
> Is it possible to have a cursor?
the original implementation had it, I need to only fix it ;-)
>
> How does one pass more than one argument, for example, if I want to
> execute "ls -l -h", what should be the format be (ignore that the two
> arguments can be combined in this case, it's just as a simple
> example)?
>
> PseudoTTYEndpoint command: '/bin/ls' arguments: #('-l -h')
>
> produces:
>
> ls: invalid option -- ' '
> Try 'ls --help' for more information.
>
>
> PseudoTTYEndpoint command: '/bin/ls' arguments: #('-l' '-h')
>
> ignores the second argument.
In this prototype implementation, only one argument is allowed because
to pass variable arguments list with FFI is not trivial. It will be
fixed soon.
>
> Thanks!
> Alistair
>
>
>> Cheers,
>> -- Pavel
>>
>>>
>>> Pharo 7.0
>>> Build information:
>>> Pharo-7.0+alpha.build.674.sha.57447e756fa6fcf1877f9d0d1cda235b3b63c807
>>> (64 Bit)
>>>
>>>
>>> Cheers,
>>> Alistair
>>>
>>>
>>>
>>>
>>>
>>>
>>> On 5 March 2018 at 10:29, Pavel Krivanek <pavel.kriva...@gmail.com> wrote:
>>>> Hi,
>>>>
>>>> Guille is working on the Iceberg improvements and he wanted to be able to
>>>> open a terminal window on top of the repository and interact with it via
>>>> the
>>>> command line. So we looked at this issue because I already in December made
>>>> some experiments with the terminal emulation in Pharo.
>>>>
>>>> In past, the Squeak had a working terminal emulation that used
>>>> PseudoTTYPlugin. The VM is not built with this code for a long time but I
>>>> tried to replace it with a small C library and then wrote an FFI interface
>>>> to it. Together with that, I ported most of the old code Squeak code to
>>>> Pharo.
>>>>
>>>> With Guille we tried to avoid usage of such external library and wrote an
>>>> FFI interface to all the required LibC functions. We were successful but we
>>>> realized that there are several issues that are limiting us.
>>>>
>>>> When you want to execute a separate process for the program that you want
>>>> to
>>>> open in terminal (typically the Bash), you need to redirect the standard IO
>>>> files, create a fork of your process, do some additional initialization in
>>>> it and call 'exec' on it. In the parent process, you change redirected IO
>>>> files back to the original values.
>>>>
>>>> But the problem is that between the FFI calls from Smalltalk the VM can do
>>>> a
>>>> lot of things including garbage collection etc. On OS X the fork() function
>>>> has the following limitation described in man:
>>>>
>>>> "There are limits to what you can do in the child process. To be totally
>>>> safe you should restrict your yourself to only executing async-signal safe
>>>> operations until such time as one of the exec functions is called. All
>>>> APIs, including global data symbols, in any framework or library should be
>>>> assumed to be unsafe after a fork() unless explicitly documented to be safe
>>>> or async-signal safe. If you need to use these frameworks in the child
>>>> process, you must exec. In this
>>>> situation it is reasonable to exec your-self. yourself."
>>>>
>>>>
>>>> As the result in most cases (but not all) the fork() and exec() pair from
>>>> the Smalltalk side fails on OS X. Linux does not have this limitation
>>>> however even there we found an issue. It is bound to the fact that fork()
>>>> makes a fork of all the parent process that uses the same resources. As
>>>> soon
>>>> as Pharo is opened in a window and X11 is involved (the window wants to be
>>>> repainted), it can lead to the VM crash.
>>>>
>>>> So we learned that unfortunately we currently cannot use image-only FFI
>>>> code
>>>> for this task. We need a C library or VM plugin.
>>>>
>>>> The repository of the terminal emulator is here:
>>>> https://github.com/pavel-krivanek/terminal
>>>>
>>>> and can be loaded using the following code:
>>>>
>>>> Metacello new
>>>> baseline: 'TerminalEmulator';
>>>> repository: 'github://pavel-krivanek/terminal/src';
>>>> load.
>>>>
>>>> #TerminalEmulator asClass compileLibrary.
>>>>
>>>>
>>>> It compiles and links the small library with only one function using the
>>>> GCC
>>>> so the machine needs to have a proper development environment.
>>>>
>>>> The terminal emulator is in very early stage and has a lot of issues like
>>>> processes cleanup, drawing, keyboard input etc. etc. If you are interested
>>>> in it, feel free to contribute.
>>>>
>>>> Cheers,
>>>> -- Pavel
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>
>>
>
