[Crash-utility] Problem with "shell" command in crash

[Dave Anderson]

Dave Anderson wrote:

> Raghuveer R wrote:
>
> > I am having some problems using the "shell" command in crash.
> >
> >         If i execute "shell" command in crash, the input commands in the shell
> > prompt do not get displayed properly. Here is what i see.
> >
> > crash> shell
> > mac:/home/raghu # 2a  a.out  addr.c  crash-4.0-3.19         dump
> >                 ^^^^^entered ls
> > mac:/home/raghu # llm22:/home/raghu # llm22:/home/raghu # llm22:/home/raghu #
> >                 ^^^^^enter      ^^^^^enter
> >
> > However, the problem disappears if i execute 'stty echo' or 'reset' in the shell prompt.
> >
> > mac:/home/raghu # llm22:/home/raghu #
> >                 ^^^^entered stty echo
> > mac:/home/raghu # echo This is fine
> > This is fine
> > mac:/home/raghu #
> >
> > Also, the problem is not found if i run crash in gdb.
> > The problem is reproducible in the latest version of crash, crash-4.0-3.19.
> >
> > Anyone knows how to fix this?
>
> Don't use it.
>
> It's actually the built-in gdb's "shell" command that's the problem.
> The command should be put on the "prohibited_list" array in
> the top-level gdb_interface.c file.
>
> To get into a shell, just enter "|" or "!" on the crash command
> line.  I should better explain that capability better in the
> "help output" page.
>
> I'll do both in the next release.
>
> Thanks,
>   Dave

BTW, the "|" or "!" command construct is just an extenstion
of the command-output-to-a-pipe capability.  It's just that
(1) there's no crash command to the left of the pipe, and
(2) since there's also no command to the right of the pipe,
it just goes into a shell.  So you can also run any shell
command like:

  crash> !do-this-command

or

  crash> |do-this-command

The exclamation point is the same as the pipe character.
It's there as a holdover from the old System V crash,
as well as being a common shell escape character.

Dave