Re: [MiNT] XaAES: bug(s) in shel_write()

["Helmut Karlowski" <helmut.karlowski@ish.de>]

Am 04.02.2016, 19:31 Uhr, schrieb Thorsten Otto:

> I recently tried to run a TOS application via shel_write(), using  an  
> extended to pass the command line parameters via ARGV. After some  
> results it looks like there are at least 2 bugs in the current  
> implementation.
> What i did wasa) construct a new enviroment block including the ARGV  
> command line parameters.b) put a pointer to that block, and a pointer to  
> the program name into a x_shell-structurec) call  
> shel_write(SHW_EXEC|SHD_ENVIRON, 0, 1, &x_shell, cmd) where cmd[0]  
> contains 0x7f

What is SHD_ENVIRON? I've found

#define SWM_ENVIRON   8
#define SW_ENVIRON    0x0800

in mt_gem.h in the xaaes-source-dir.

>  What happened was, that tw-call tried to execute a program named "-p"  
> (the first parameter that was intended to be passed to my program).After

What exactly did you write in ARGV?

> some investigation, i think found out the reason for this. When running  
> a TOS program, shel_write executes tw-call instead (or whatever happens  
> to be in the environment variable TOSRUN), constructing a new command  
> line to included the original program name. There are however a few  
> things that  look strange:a) in function launch(), there is code like:
>         if (wiscr == 1 || p_tail[0] == 0x7f || (unsigned char)p_tail[0]  
> == 0xff)
>         {
>             /* In this case the string CAN ONLY BE null terminated. */
>             longtail = strlen(p_tail + 1);
>             if (longtail > 124)
>                 longtail = 124;
>             DIAG((D_shel, NULL, "ARGV!  longtail = %ld", longtail));
>         }

longtail is not used in ARGV, it rather a flag in this case (at least this  
is how I understand this code).

The real tail is made up from tail in #584 (my branch):
          strncpy(new_tail + new_tailsize + 1, tail + 1, tailsize);

tailsize is the length used in make_argv().

>    Why is the commandline restricted to 124, when it was expclicity  
> specified that ARGV method should be used? The variable longtail is not  
> adjusted later,

It is:

         if (tailsize > 126)
         {
            longtail = tailsize;
            tail[0] = 0x7f;
...

> nor does the function try to get the actial parameters from the ARGV  
> environment variable.

Looks like that is not supported by XaAES.

> b) if the variable longtail is set, a new enviroment is created using  
> make_argv(). However, make_argv() stashes the build environment block  
> into C.env, while create_process() passes my Environment block to  
> tw-call.

Only if SW_ENVIRON is set.

> The outcome of this is that tw-call parses the original command line  
> parameters, instead of the ones including its own path, ie. it only  
> sees"myprogram -p" instead of "tw-call myprogram -p".

Do you have a simple test-case?

-Helmut


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