[Libguestfs] [PATCH] Fix error launching libguestfs when euid != uid

[Matthew Booth]

On 20/09/10 14:43, Richard W.M. Jones wrote:
> Improved patch.  This copies your code to set real UID and GID
> before the exec.
>
> Rich.
>
> -- Richard Jones, Virtualization Group, Red Hat
> http://people.redhat.com/~rjones virt-top is 'top' for virtual machines.
> Tiny program with many powerful monitoring features, net stats, disk
> stats, logging, etc. http://et.redhat.com/~rjones/virt-top
>
>
> 0001-Fix-error-launching-libguestfs-when-euid-uid.patch
>
>
>  From d00e2fb8c2e26e0a48954472b52bd0be877e9ce6 Mon Sep 17 00:00:00 2001
> From: Richard W.M. Jones<rjones at redhat.com>
> Date: Mon, 20 Sep 2010 14:02:06 +0100
> Subject: [PATCH] Fix error launching libguestfs when euid != uid.
>
> When writing to a RHEV target, virt-v2v launches the libguestfs
> appliance with euid:egid = 36:36, which is required to write to
> an NFS target using root_squash.
>
> Since we changed to using a cached appliance, this causes an error on
> start up, as the cached files are owned by root, but the cache directory
> is owned by 36:36.  The reason is that bash resets euid to uid and
> egid to gid so when febootstrap-supermin-helper is executed, it runs as
> root:root.  The cache directory was created by libguestfs directly so
> it has the correct ownership.
>
> This patch fixes the issue by using explicit fork/exec instead of
> system (ie. not going via a shell) and by setting the real UID and
> GID to the effective UID and GID before execing.
> ---
>   src/appliance.c |  133 ++++++++++++++++++++++++++++++++++++++++++++----------
>   1 files changed, 108 insertions(+), 25 deletions(-)

ACK. This now works for me.

Matt
-- 
Matthew Booth, RHCA, RHCSS
Red Hat Engineering, Virtualisation Team

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