[Libguestfs] [PATCH] Enable coredumps to be captured from the appliance (RHBZ#619334).

[Richard W.M. Jones]

On Sat, Jul 31, 2010 at 05:20:19PM +0100, Richard W.M. Jones wrote:
> This is a slightly unsatisfactory patch which allows coredumps to be
> captured when they occur inside the appliance.  You can capture
> coredumps by doing:
> 
>   export LIBGUESTFS_COREDUMP=/sysroot/core.%t.%p.%e
> 
> or equivalently:
> 
>   g.set_coredump ("/sysroot/core.%t.%p.%e")
> 
> or variations thereof, see the manual page.

Actually it strikes me that this API is wrong.  It should be
something like:

  set-coredump-file      eg. set-coredump-file /core.%t.%p.%e

    - Coredump to a mounted guest filesystem.  This would add the
      /sysroot/ prefix automatically.  The %-patterns would be
      some limited subset of what the kernel supports.

  set-coredump-device    eg. set-coredump-device /dev/sdb

    - Coredump to a capture device.  This would be implemented at
      first using a coredump-to-pipe, but we could later change
      the implemention to coredump directly to a device if we got
      a patch into the kernel to support it.

  clear-coredump

    - Clear the coredump file/device.  Equivalent to setting it to
      NULL right now.

This interface is more extensible and future-proof.  We can extend it
by adding more set-coredump-* methods.  It's future-proof because it
doesn't depend so closely on the current kernel implementation.

The environment variable would have to be changed as well.

	- - - -

The ideal future enhancement would be to get a stack trace without
needing the coredump + gdb step.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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