[Crash-utility] [PATCH 1/2] libgcore: fix get notesize calculation

[HATAYAMA Daisuke]

Hello Lei,

Sorry for very late response.

I'm now reviewing your patches.

From: Lei Wen <leiwen at marvell.com>
Subject: [PATCH 1/2] libgcore: fix get notesize calculation
Date: Sat, 11 Feb 2012 22:44:14 -0800

> The logic in the kernel is if regset get method return not zero value,
> which means error in that case, then it should skip this notesize calculation.
> Align this logic in the libgcore with kernel.
> 
> Signed-off-by: Lei Wen <leiwen at marvell.com>
> ---
>  extensions/libgcore/gcore_coredump.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/extensions/libgcore/gcore_coredump.c b/extensions/libgcore/gcore_coredump.c
> index 8a8855d..e2d9941 100644
> --- a/extensions/libgcore/gcore_coredump.c
> +++ b/extensions/libgcore/gcore_coredump.c
> @@ -454,7 +454,7 @@ fill_thread_core_info(struct elf_thread_core_info *t,
>  		    !regset->active(task_to_context(t->task), regset))
>  			continue;
>  		data = (void *)GETBUF(regset->size);
> -		if (!regset->get(task_to_context(t->task), regset, regset->size,
> +		if (regset->get(task_to_context(t->task), regset, regset->size,
>  				 data))
>  			continue;
>  		if (regset->callback)
> -- 
> 1.7.5.4
> 

I borrowed most of logic in gcore from kernel source code for ease of
development and for ease of porting each architecture's implementation
following regset interface.

The interface for get method in gcore command is different from
kernel's. Originally, it returns 0 in a successfull case, and
otherwise returns non-zero values. But in gcore, such get method
returns TRUE in a successfull case, and otherwise FALSE.

I cannot recall why I made this change at that time precisely. But OK,
I'll revert it into the original one. Based on the original motivation
of why I adapted regset interface, it's better to keep it original.

BTW, looking at your 2nd patch, fpa_get() and vfp_get() bahaves
differently w.r.t. the above mentioned one: fpa_get() returns 0 in a
sucessfull case, but vfp_get() TRUE.

Is it OK that I'll modify vfp_get() so that it returns 0 in a
successfull state?

Furthermore, these days I'm beginning with the current design of gcore
command is too large to maintain. I guess most users of this command
requires only a small part of the features currently gcore command
provides. In other words, they are satisfied only with seeing memory
contents and backtrace using gdb. They don't need acurate restoration
of register values. For the other direction, porting kernel source
code directly, such as elf_core_dump() and regset interface, itself
might be too large. I will perhaps rewrite gcore command entirely
compactly. Please keep it mind.

Thanks.
HATAYAMA, Daisuke