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.
>> - 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?
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.
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
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>
>
