From 44afd4c1f26379b32f62690cf19e06022cafa994 Mon Sep 17 00:00:00 2001

From: "Richard W.M. Jones" <rjones@redhat.com>

Date: Thu, 2 Jun 2016 14:51:12 +0100

Subject: [PATCH] builder: Warn if --output is a host partition (RHBZ#1342337).

But allow the warning to be turned off using --no-warn-if-partition.

Ming Xie tried to create a bootable USB key using

'virt-p2v-make-disk -o /dev/sdX1'.  That works, but doesn't create a

bootable key because it puts everything into the first partition.

Emit a warning if someone tries to do this to try to prevent user

error:

  virt-builder: warning: output device (/dev/sdb1) is a partition.  If you

  are writing to a USB key or external drive then you probably need to write

  to the whole device, not to a partition.  If this warning is wrong then you

  can disable it with --no-warn-if-partition

(cherry picked from commit 7274f11ad408bcd4299ba82b3b26f46e62930d03)

---

 builder/builder.ml       | 9 +++++++++

 builder/cmdline.ml       | 6 ++++++

 builder/cmdline.mli      | 1 +

 builder/virt-builder.pod | 9 +++++++++

 4 files changed, 25 insertions(+)

diff --git a/builder/builder.ml b/builder/builder.ml

index a6f92c7..ac4c748 100644

--- a/builder/builder.ml

+++ b/builder/builder.ml

@@ -268,6 +268,15 @@ let main () =

   (* --- If we get here, we want to create a guest. --- *)

+  (* Warn if the user might be writing to a partition on a USB key. *)

+  (match cmdline.output with

+   | Some device when is_partition device ->

+      if cmdline.warn_if_partition then

+        warning (f_"output device (%s) is a partition.  If you are writing to a USB key or external drive then you probably need to write to the whole device, not to a partition.  If this warning is wrong then you can disable it with --no-warn-if-partition")

+                device;

+   | Some _ | None -> ()

+  );

+

   (* Download the template, or it may be in the cache. *)

   let template =

     let template, delete_on_exit =

diff --git a/builder/cmdline.ml b/builder/cmdline.ml

index 4893cbf..5205fe6 100644

--- a/builder/cmdline.ml

+++ b/builder/cmdline.ml

@@ -51,6 +51,7 @@ type cmdline = {

   smp : int option;

   sources : (string * string) list;

   sync : bool;

+  warn_if_partition : bool;

 }

 let parse_cmdline () =

@@ -115,6 +116,7 @@ let parse_cmdline () =

   let add_source arg = push_front arg sources in

   let sync = ref true in

+  let warn_if_partition = ref true in

   let argspec = [

     "--arch",    Arg.Set_string arch,       "arch" ^ " " ^ s_"Set the output architecture";

@@ -163,6 +165,8 @@ let parse_cmdline () =

     "--smp",     Arg.Int set_smp,           "vcpus" ^ " " ^ s_"Set number of vCPUs";

     "--source",  Arg.String add_source,     "URL" ^ " " ^ s_"Set source URL";

     "--no-sync", Arg.Clear sync,            " " ^ s_"Do not fsync output file on exit";

+    "--no-warn-if-partition", Arg.Clear warn_if_partition,

+                                            " " ^ s_"Do not warn if writing to a partition";

   ] in

   let customize_argspec, get_customize_ops = Customize_cmdline.argspec () in

   let customize_argspec =

@@ -212,6 +216,7 @@ read the man page virt-builder(1).

   let smp = !smp in

   let sources = List.rev !sources in

   let sync = !sync in

+  let warn_if_partition = !warn_if_partition in

   (* No arguments and machine-readable mode?  Print some facts. *)

   if args = [] && machine_readable then (

@@ -323,4 +328,5 @@ read the man page virt-builder(1).

     gpg = gpg; list_format = list_format; memsize = memsize;

     network = network; ops = ops; output = output;

     size = size; smp = smp; sources = sources; sync = sync;

+    warn_if_partition = warn_if_partition;

   }

diff --git a/builder/cmdline.mli b/builder/cmdline.mli

index 4c201dd..854db61 100644

--- a/builder/cmdline.mli

+++ b/builder/cmdline.mli

@@ -39,6 +39,7 @@ type cmdline = {

   smp : int option;

   sources : (string * string) list;

   sync : bool;

+  warn_if_partition : bool;

 }

 val parse_cmdline : unit -> cmdline

diff --git a/builder/virt-builder.pod b/builder/virt-builder.pod

index 545b134..94ba430 100644

--- a/builder/virt-builder.pod

+++ b/builder/virt-builder.pod

@@ -495,6 +495,15 @@ Note that you should not point I<--source> to sources that you don't

 trust (unless the source is signed by someone you do trust).  See also

 the I<--no-network> option.

+=item B<--no-warn-if-partition>

+

+Do not emit a warning if the output device is a partition.  This

+warning avoids a common user error when writing to a USB key or

+external drive, when you should normally write to the whole device

+(S<I<--output /dev/sdX>>), not to a partition on the device

+(S<I<--output /dev/sdX1>>).  Use this option to I<suppress> this

+warning.

+

 =item B<-v>

 =item B<--verbose>

-- 

1.8.3.1