[Crash-utility] Fix bug of list -h

[Dave Anderson]

----- Original Message -----
> Hello Dave,
> 
> When investigating list command, I found the "-h" is involved but not
> discussed in help page. And then I tried to use, but I find some
> problems with it.

There are "problems" with it because it is not supported/advertised.
Either I started work on it and never completed it, or maybe I realized
that there was no need for it.  I honestly don't remember.  In any case,
Petr Tesarik was planning to look into resurrecting it as well:

  [Crash-utility] What should "list -h" be doing?
  https://www.redhat.com/archives/crash-utility/2012-April/msg00030.html  

Petr, is this patch what you had in mind?

Dave
 
  
> The first, I made patch to show it. The "ld->start" should be the
> pointer to the structure list_head.
> 
> And the second one, I am not sure about the reason why you don't
> display the node related to the address user input. I will take the
> tasks of task_struct as an example.
> 
> 
> crash> task_struct.tasks ffff8800371a0ac0
>    tasks = {
>      next = 0xffffffff81a8d468,
>      prev = 0xffff88004a9e0f88
>    }
> crash> list task_struct.tasks -s task_struct.tasks -h ffff8800371a0ac0
> ffffffff81a8d020
>    tasks = {
>      next = 0xffff88004eaf1908,
>      prev = 0xffff8800371a0f08
>    }
> ffff88004eaf14c0
>    tasks = {
>      next = 0xffff88004eaf0ec8,
>      prev = 0xffffffff81a8d468
>    }
> ...
> 
> As the command shows, the command neglect the task_struct at
> ffff8800371a0ac0. I don't know why it is omitted. And if only one node
> is in the list, why prints "(empty)"?
> 
>                  readmem(ld->start, KVADDR, &ld->start, sizeof(void *),
>                          "LIST_HEAD contents", FAULT_ON_ERROR);
>                  if (ld->start == ld->end) {
>                          fprintf(fp, "(empty)\n");
>                          return;
>                  }
> 
> 
> --
> --
> Regards
> Qiao Nuohan
> 
> 
> 
> --
> Crash-utility mailing list
> Crash-utility at redhat.com
> https://www.redhat.com/mailman/listinfo/crash-utility
>