lib, tools, v2v: Use unsafe flag when reading (but NOT writing) hives.

Pass the HIVEX_OPEN_UNSAFE flag when opening hives for reading.
Do NOT pass it when opening hives for writing.

This should make inspection, virt-win-reg and virt-v2v more tolerant
about handling Windows Registry corruption, without increasing the
risk of causing new corruption in hives.

lib/inspect-apps.c

@@ -792,7 +792,9 @@ list_applications_windows (guestfs_h *g, struct inspect_fs *fs)
     return NULL;
 
   if (guestfs_hivex_open (g, software_path,
-                          GUESTFS_HIVEX_OPEN_VERBOSE, g->verbose, -1) == -1)
+                          GUESTFS_HIVEX_OPEN_VERBOSE, g->verbose,
+                          GUESTFS_HIVEX_OPEN_UNSAFE, 1,
+                          -1) == -1)
     return NULL;
 
   /* Allocate apps list. */

lib/inspect-fs-windows.c

@@ -283,7 +283,9 @@ check_windows_software_registry (guestfs_h *g, struct inspect_fs *fs)
   bool ignore_currentversion = false;
 
   if (guestfs_hivex_open (g, software_path,
-                          GUESTFS_HIVEX_OPEN_VERBOSE, g->verbose, -1) == -1)
+                          GUESTFS_HIVEX_OPEN_VERBOSE, g->verbose,
+                          GUESTFS_HIVEX_OPEN_UNSAFE, 1,
+                          -1) == -1)
     return -1;
 
   node = guestfs_hivex_root (g);
@@ -405,7 +407,9 @@ check_windows_system_registry (guestfs_h *g, struct inspect_fs *fs)
     { NULL /* current control set */, "Services", "Tcpip", "Parameters" };
 
   if (guestfs_hivex_open (g, system_path,
-                          GUESTFS_HIVEX_OPEN_VERBOSE, g->verbose, -1) == -1)
+                          GUESTFS_HIVEX_OPEN_VERBOSE, g->verbose,
+                          GUESTFS_HIVEX_OPEN_UNSAFE, 1,
+                          -1) == -1)
     goto out;
 
   root = guestfs_hivex_root (g);

tools/virt-win-reg

@@ -335,7 +335,8 @@ if (!$merge) {                  # Export mode.
     download_hive ($hivefile, $hiveshortname);
 
     # Open it.
-    my $h = Win::Hivex->open ("$tmpdir/$hiveshortname", debug => $debug);
+    my $h = Win::Hivex->open ("$tmpdir/$hiveshortname",
+                              unsafe => 1, debug => $debug);
 
     unless ($name) {
         # Export it.

v2v/windows.ml

@@ -49,7 +49,8 @@ and (=~) str rex =
 
 let with_hive_readonly (g : Guestfs.guestfs) hive_filename f =
   let verbose = verbose () in
-  g#hivex_open ~write:false ~verbose (* ~debug:verbose *) hive_filename;
+  g#hivex_open ~write:false ~unsafe:true ~verbose (* ~debug:verbose *)
+               hive_filename;
   protect ~f:(
     fun () ->
       let root = g#hivex_root () in