Per-task file descriptors and eventually a "real" shell

[Ian Caddy]

Chris, we are using 4.10, and this redirector does not appear in that.

Isaac, our system is a bit more complicated than just a shell, as we 
have a menu driven maintenance system on top of the shell.

Basically we create a task with the device name (such as "/dev/com1" or 
/dev/usb" or "/dev/pty0"), which we use for the in and out directions 
for our IO, then when we drill down to the shell we use the following 
commands to start the shell:

The device name is stored in the structure "ptUsrApp->devname"

FILE             *ostd[3];

    /* Save old environment */
    ostd[0] = stdin;
    ostd[1] = stdout;
    ostd[2] = stderr;


    stdin  = fopen(ptUserApp->devname, "r");
    stdout = fopen(ptUserApp->devname, "w");
    stderr = fopen(ptUserApp->devname, "w");

    rtems_shell_main_loop( &ptDispShell->env );

    /* Upon exit from the shell */
    fclose(stdin);
    fclose(stdout);
    fclose(stderr);

    stderr = ostd[2];
    stdout = ostd[1];
    stdin  = ostd[0];

This works fine for us on 4.10.

regards,

Ian Caddy



On 5/10/2015 9:20 PM, Isaac Gutekunst wrote:
> Hi Ian,
>
> That's exciting! I clearly should have looked a bit harder before
> posting. Is there any special config? Or is it sufficient to instantiate
> another shell with a different file descriptor for IO?
>
> Isaac
>
> On 10/04/2015 09:22 PM, Ian Caddy wrote:
>> Hi Isaac,
>>
>> On 3/10/2015 4:24 AM, Isaac Gutekunst wrote:
>>> Hey,
>>>
>>>
>>> The hack would be that file descriptors 0,1 and 2 are not part of a
>>> global namespace of file descriptors, and potentially refer to different
>>> actual IO devices on a per task basis.
>>>
>>> The motivation here would be creating a more functional shell and
>>> support easy IO redirection for logging, and running multiple shell
>>> instances, perhaps via multiple telnet and serial sessions.
>>>
>>
>> Maybe I am missing something, but we do all this currently with the
>> shell.
>>
>> We have a serial port access, and we have multiple telnet / ssh access
>> to our devices providing
>> multiple shells with no problems.
>>
>> We also redirect the stdio for all the application tasks to print to
>> an application log instead
>> on the shell.  This is all completely doable now, as as far as I know
>> newlib provides a per
>> task stdin, etc.
>>
>> Just start your task and point them where you want them to go.
>>
>> regards,
>>
>> Ian Caddy
>>
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-- 
Ian Caddy
Goanna Technologies Pty Ltd
+61 8 9444 2634