Libguestfs - Jul 2019 - [PATCH] v2v: -i vmx: Use scp -T option if available to unbreak scp (RHBZ#1733168).

Tested using:

cd v2v
LIBGUESTFS_BACKEND=direct ../run virt-v2v -i vmx -it ssh
"ssh://localhost/$PWD/test-v2v-i-vmx-1.vmx" -o null -v -x

and manually examining the debug output.

Thanks: Ming Xie, Jakub Jelen.
---
 v2v/input_vmx.ml | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/v2v/input_vmx.ml b/v2v/input_vmx.ml
index 5441bccb9..4a82a867f 100644
--- a/v2v/input_vmx.ml
+++ b/v2v/input_vmx.ml
@@ -61,6 +61,13 @@ let server_of_uri { Xml.uri_server }  let path_of_uri {
Xml.uri_path }    match uri_path with None -> assert false | Some p -> p
 
+let scp_supports_T_option = lazy (
+  let cmd = "LANG=C scp -T |& grep \"unknown option\""
in
+  if verbose () then
+    eprintf "%s\n%!" cmd;
+  Sys.command cmd <> 0
+)
+
 (* 'scp' a remote file into a temporary local file, returning the path
  * of the temporary local file.
  *)
@@ -68,8 +75,9 @@ let scp_from_remote_to_temporary uri tmpdir filename    let
localfile = tmpdir // filename in
 
   let cmd -    sprintf "scp%s%s %s%s:%s %s"
+    sprintf "scp%s%s%s %s%s:%s %s"
             (if verbose () then "" else " -q")
+            (if Lazy.force scp_supports_T_option then " -T" else
"")
             (match port_of_uri uri with
              | None -> ""
              | Some port -> sprintf " -P %d" port)
-- 
2.22.0

On Thursday, 25 July 2019 16:01:59 CEST Richard W.M. Jones
wrote:
> Tested using:
> 
> cd v2v
> LIBGUESTFS_BACKEND=direct ../run virt-v2v -i vmx -it ssh
"ssh://localhost/$PWD/test-v2v-i-vmx-1.vmx" -o null -v -x
> 
> and manually examining the debug output.
> 
> Thanks: Ming Xie, Jakub Jelen.
> ---
This (the issue, and the solution) is rather ugly, although I do not
see an easier solution than either
a) switch to the sftp(1) utility (and thus switch from scp to sftp)
b) use a ssh library (libssh) for fetching the vmx file

So for now I'd say to go with this, with the following fixes:
> +let scp_supports_T_option = lazy (
> +  let cmd = "LANG=C scp -T |& grep \"unknown
option\"" in
> +  if verbose () then
> +    eprintf "%s\n%!" cmd;
> +  Sys.command cmd <> 0
There is already Tools_utils.shell_command that does the 3 lines above.

Also, the Lazy is not needed here, as the vmx file is downloaded using
scp_from_remote_to_temporary only once.  So I'd move the
scp_supports_T_option helper within scp_from_remote_to_temporary.

-- 
Pino Toscano