Re: [Libguestfs] [PATCH nbdkit] vddk: Disallow password=-
On 6/1/20 11:07 AM, Richard W.M. Jones wrote:
This has been broken since we added the reexec code
(commit 155af3107292c351d54ed42c732f4a67bb9aa910) because it
tried to read the password twice (before and after the reexec) failing
the second time because stdin had already been reopened on /dev/null.
Virt-v2v used this feature, but I will change virt-v2v instead.
---
plugins/vddk/nbdkit-vddk-plugin.pod | 7 +------
plugins/vddk/vddk.c | 4 ++++
2 files changed, 5 insertions(+), 6 deletions(-)
This is the simplest "fix", by avoiding the problem. It may still be
possible to come up with something more robust, where (since we are
already special-casing for "-" as the password value) we read the
password prior to re-exec, and rewrite the command line of the re-exec
to instead consume a temporary file. But that's more complex, and
doesn't stop us from pushing this now; if we ever do implement the more
complex patch, we can roll back the documentation change.
And I already see that you have the counterpart v2v patch that hoists
the reading of the password into v2v instead of worrying about vddk; the
v2v hack of using a temporary file "works" in spite of our re-exec
reading it twice, even if we want to eventually reach the point where a
more complex patch in the vddk plugin would only read the password once
before re-exec.
ACK.
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3226
Virtualization: qemu.org | libvirt.org