[Qemu-devel] [PATCH] block/curl: Add support for Secure Shell (ssh/sftp) block device

[Richard W.M. Jones]

I got it working with Curl, patch attached.

However there are multiple issues (these are mainly notes for myself):

(1) libcurl cannot read the size of the file.  I had to hard-code
this.  This is probably just a shortcoming of libcurl (libssh2/sftp
itself can read the size of files).  Will try to work on a patch for
upstream.

(2) Fedora's curl (which is heavily patched) is broken in some way and
deadlocks itself.  Upstream curl from git works better.  I haven't yet
identified which patch/commit is responsible.

(3) ssh-agent authentication doesn't work.  It appears that either
ssh-agent itself doesn't like multiple connections from a single
process (qemu), or libcurl/libssh2 is having a problem with making
multiple connections out to ssh-agent.  If I disable ssh-agent auth,
it works.  Still investigating this.

(4) You must specify a user@ in the URL, else libcurl tries to
authenticate as user "".  I will see if I can send a fix for this
upstream.

(5) Although it gets much of the way through a boot of a guest, it
eventually segfaults.  Still investigating this.

(6) There are several more issues marked by XXX's in the code.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
virt-p2v converts physical machines to virtual machines.  Boot with a
live CD or over the network (PXE) and turn machines into KVM guests.
http://libguestfs.org/virt-v2v

0001-block-curl-Add-support-for-Secure-Shell-ssh-sftp-blo.patch
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