Libguestfs - Dec 2018 - [PATCH v2] v2v: don't fail when virtio-win does not have qemu-ga

This is my version of this patch which I think improves it in a number
of ways.  Firstly instead of having the bare boolean parameter
‘ok_if_missing’ we pass in the function we want to call along the
directory missing path.

This change then allows us to print a more useful error or warning
message given the context of the call, and the new message is
actionable too, so the user knows what has to be done to correct the
problem.

The other changes are all whitespace.

This is only compile tested, please see if it fixes the problem in the
slow tests.

Rich.

From: Tomáš Golembiovský <tgolembi@redhat.com>

It should not be error to use virtio-win ISO that does not have Linux
packages of QEMU Guest Agent. Only oVirt/RHV guest tools ISO has such
packages now. Regular virtio-win ISO does not have them and maybe never
will.

Signed-off-by: Tomáš Golembiovský <tgolembi@redhat.com>
---
 v2v/windows_virtio.ml | 77 ++++++++++++++++++++++++++-----------------
 1 file changed, 47 insertions(+), 30 deletions(-)

diff --git a/v2v/windows_virtio.ml b/v2v/windows_virtio.ml
index 0b9bdfff3..59d83c42d 100644
--- a/v2v/windows_virtio.ml
+++ b/v2v/windows_virtio.ml
@@ -204,8 +204,12 @@ and install_linux_tools g inspect        let src_path =
"linux" // os in
       let dst_path = "/var/tmp" in
       debug "locating packages in %s" src_path;
-      let packages = copy_from_virtio_win g inspect src_path dst_path
-        (fun _ _ -> true) in
+      let packages +        copy_from_virtio_win g inspect src_path dst_path
+                             (fun _ _ -> true)
+                             (fun () ->
+                               warning "guest tools directory ‘%s’ is
missing from the virtio-win directory or ISO.\n\nGuest tools are only provided
in the RHV Guest Tools ISO, so this can happen if you are using the version of
virtio-win which contains just the virtio drivers.  In this case only virtio
drivers can be installed in the guest, and installation of Guest Tools will be
skipped."
+                              src_path) in
       debug "done copying %d files" (List.length packages);
       let packages = List.map ((//) dst_path) packages in
       try
@@ -286,36 +290,46 @@ and ddb_regedits inspect drv_name drv_pciid   * been
copied.
  *)
 and copy_drivers g inspect driverdir -  [] <> copy_from_virtio_win g
inspect "/" driverdir virtio_iso_path_matches_guest_os
+  [] <> copy_from_virtio_win g inspect "/" driverdir
+    virtio_iso_path_matches_guest_os
+    (fun () ->
+      error "driver directory ‘%s’ is missing from the virtio-win
directory or ISO.\n\nThis should not happen and may indicate that virtio-win or
virt-v2v is broken in some way.  Please report this as a bug with a full debug
log."
+            driverdir)
 
 (* Copy all files from virtio_win directory/ISO located in [srcdir]
  * subdirectory and all its subdirectories to the [destdir]. The directory
  * hierarchy is not preserved, meaning all files will be directly in [destdir].
  * The file list is filtered based on [filter] function.
  *
+ * If [srcdir] is missing from the ISO then [missing ()] is called
+ * which might give a warning or error.
+ *
  * Returns list of copied files.
  *)
-and copy_from_virtio_win g inspect srcdir destdir filter +and
copy_from_virtio_win g inspect srcdir destdir filter missing    let ret = ref []
in
   if is_directory virtio_win then (
     let dir = virtio_win // srcdir in
     debug "windows: copy_from_virtio_win: guest tools source directory
%s" dir;
 
-    let cmd = sprintf "cd %s && find -L -type f" (quote dir)
in
-    let paths = external_command cmd in
-    List.iter (
-      fun path ->
-        if filter path inspect then (
-          let source = dir // path in
-          let target_name = String.lowercase_ascii (Filename.basename path) in
-          let target = destdir // target_name in
-          debug "windows: copying guest tools bits: 'host:%s'
-> '%s'"
-                source target;
+    if not (is_directory srcdir) then missing ()
+    else (
+      let cmd = sprintf "cd %s && find -L -type f" (quote
dir) in
+      let paths = external_command cmd in
+      List.iter (
+        fun path ->
+          if filter path inspect then (
+            let source = dir // path in
+            let target_name = String.lowercase_ascii (Filename.basename path)
in
+            let target = destdir // target_name in
+            debug "windows: copying guest tools bits: 'host:%s'
-> '%s'"
+                  source target;
 
-          g#write target (read_whole_file source);
-          List.push_front target_name ret
-        )
+            g#write target (read_whole_file source);
+            List.push_front target_name ret
+          )
       ) paths
+    )
   )
   else if is_regular_file virtio_win then (
     debug "windows: copy_from_virtio_win: guest tools source ISO %s"
virtio_win;
@@ -327,21 +341,24 @@ and copy_from_virtio_win g inspect srcdir destdir filter  
let vio_root = "/" in
       g2#mount_ro "/dev/sda" vio_root;
       let srcdir = vio_root ^ "/" ^ srcdir in
-      let paths = g2#find srcdir in
-      Array.iter (
-        fun path ->
-          let source = srcdir ^ "/" ^ path in
-          if g2#is_file source ~followsymlinks:false &&
-               filter path inspect then (
-            let target_name = String.lowercase_ascii (Filename.basename path)
in
-            let target = destdir ^ "/" ^ target_name in
-            debug "windows: copying guest tools bits: '%s:%s'
-> '%s'"
-                  virtio_win path target;
+      if not (g2#is_dir srcdir) then missing ()
+      else (
+        let paths = g2#find srcdir in
+        Array.iter (
+          fun path ->
+            let source = srcdir ^ "/" ^ path in
+            if g2#is_file source ~followsymlinks:false &&
+                filter path inspect then (
+              let target_name = String.lowercase_ascii (Filename.basename path)
in
+              let target = destdir ^ "/" ^ target_name in
+              debug "windows: copying guest tools bits: '%s:%s'
-> '%s'"
+                    virtio_win path target;
 
-            g#write target (g2#read_file source);
-            List.push_front target_name ret
-          )
+              g#write target (g2#read_file source);
+              List.push_front target_name ret
+            )
         ) paths;
+      );
       g2#close()
     with Guestfs.Error msg ->
       error (f_"%s: cannot open virtio-win ISO file: %s") virtio_win
msg
-- 
2.19.0.rc0