[Libguestfs] [PATCH 2/3] v2v: -i ova: Ignore non-existent files mentioned in *.mf.

[Richard W.M. Jones]

Some OVA files generated by VMware have a *.mf file which contains
checksums for files which don't exist in the OVA.  Ignore these
checksums.

Thanks: Nisim Simsolo.
---
 builder/builder.ml           |  3 +++
 common/mltools/checksums.ml  | 28 +++++++++++++++++++++-------
 common/mltools/checksums.mli |  2 ++
 v2v/input_ova.ml             |  9 ++++++++-
 4 files changed, 34 insertions(+), 8 deletions(-)

diff --git a/builder/builder.ml b/builder/builder.ml
index 83c7aefed..2ed7cb97a 100644
--- a/builder/builder.ml
+++ b/builder/builder.ml
@@ -318,6 +318,9 @@ let main () =
        | Checksums.Mismatched_checksum (csum, csum_actual) ->
           error (f_"%s checksum of template did not match the expected checksum!\n  found checksum: %s\n  expected checksum: %s\nTry:\n - Use the ‘-v’ option and look for earlier error messages.\n - Delete the cache: virt-builder --delete-cache\n - Check no one has tampered with the website or your network!")
                 (Checksums.string_of_csum_t csum) csum_actual (Checksums.string_of_csum csum)
+       | Checksums.Missing_file ->
+          error (f_"%s: template not downloaded or deleted.  You may have run ‘virt-builder --delete-cache’ in parallel.")
+                template
       )
 
     | { Index.checksums = None } ->
diff --git a/common/mltools/checksums.ml b/common/mltools/checksums.ml
index 4dd69e734..fdeae1dff 100644
--- a/common/mltools/checksums.ml
+++ b/common/mltools/checksums.ml
@@ -30,6 +30,7 @@ type csum_t =
 type csum_result =
   | Good_checksum
   | Mismatched_checksum of csum_t * string
+  | Missing_file
 
 let string_of_csum_t = function
   | SHA1 _ -> "sha1"
@@ -72,18 +73,31 @@ let compute_checksum csum_type ?tar filename =
     let csum_str = fst (String.split " " line) in
     of_string csum_type csum_str
 
+(* Check if the direct file exists or if it exists in the tarball. *)
+let file_exists ?tar filename =
+  match tar with
+  | None -> Sys.file_exists filename
+  | Some tar ->
+     let cmd =
+       sprintf "tar tf %s %s >/dev/null 2>&1" (quote tar) (quote filename) in
+     Sys.command cmd = 0
+
 let verify_checksum csum ?tar filename =
-  let csum_type = string_of_csum_t csum in
-  let csum_actual = compute_checksum csum_type ?tar filename in
-  if csum = csum_actual then
-    Good_checksum
-  else
-    Mismatched_checksum (csum, string_of_csum csum_actual)
+  if not (file_exists ?tar filename) then
+    Missing_file
+  else (
+    let csum_type = string_of_csum_t csum in
+    let csum_actual = compute_checksum csum_type ?tar filename in
+    if csum = csum_actual then
+      Good_checksum
+    else
+      Mismatched_checksum (csum, string_of_csum csum_actual)
+  )
 
 let verify_checksums checksums filename =
   List.fold_left (
     fun acc c ->
       match acc with
       | Good_checksum -> verify_checksum c filename
-      | Mismatched_checksum _ as acc -> acc
+      | (Mismatched_checksum _|Missing_file) as acc -> acc
   ) Good_checksum checksums
diff --git a/common/mltools/checksums.mli b/common/mltools/checksums.mli
index d45b29dfd..533e399bf 100644
--- a/common/mltools/checksums.mli
+++ b/common/mltools/checksums.mli
@@ -25,6 +25,8 @@ type csum_result =
   | Good_checksum
   (* expected checksum, actual checksum. *)
   | Mismatched_checksum of csum_t * string
+  (* referenced file does not exist *)
+  | Missing_file
 
 val of_string : string -> string -> csum_t
 (** [of_string type value] returns the [csum_t] for the specified
diff --git a/v2v/input_ova.ml b/v2v/input_ova.ml
index 59dbe6f5f..f23a1f2a9 100644
--- a/v2v/input_ova.ml
+++ b/v2v/input_ova.ml
@@ -234,7 +234,14 @@ object
                 | Checksums.Good_checksum -> ()
                 | Checksums.Mismatched_checksum (_, actual) ->
                    error (f_"checksum of disk %s does not match manifest %s (actual %s(%s) = %s, expected %s(%s) = %s)")
-                         disk mf mode disk actual mode disk expected;
+                         disk mf mode disk actual mode disk expected
+                | Checksums.Missing_file ->
+                   (* RHBZ#1570407: Some OVA files generated by VMware
+                    * reference non-existent components in the *.mf file.
+                    * Generate a warning and ignore it.
+                    *)
+                   warning (f_"%s has a checksum for non-existent file %s (ignored)")
+                           mf disk
               )
               else
                 warning (f_"unable to parse line from manifest file: %S") line;
-- 
2.16.2