Libguestfs - Jan 2015 - [PATCH 1/2] mllib: add simple qemu filename sanitizing function

It mimics a bit in OCaml the logic used in
commit a95214b1985e694946e3426120a6fdc13a3f081f (for the main library)
and commit 588af1953e5f7ab74009b9175cc5d3efb8bb651a (in disk-create),
so in OCaml tools direct calls to qemu/qemu-img with filenames provided
by the user can properly handle filenames with e.g. ':'.
---
 mllib/common_utils.ml  | 13 +++++++++++++
 mllib/common_utils.mli |  8 ++++++++
 2 files changed, 21 insertions(+)

diff --git a/mllib/common_utils.ml b/mllib/common_utils.ml
index b143710..4d3bf95 100644
--- a/mllib/common_utils.ml
+++ b/mllib/common_utils.ml
@@ -603,3 +603,16 @@ let is_directory path  let absolute_path path    if not
(Filename.is_relative path) then path
   else Sys.getcwd () // path
+
+(* Sanitizes a filename for passing it safely to qemu/qemu-img.
+ *
+ * If the filename is something like "file:foo" then qemu-img will
+ * try to interpret that as "foo" in the file:/// protocol.  To
+ * avoid that, if the path is relative prefix it with "./" since
+ * qemu-img won't try to interpret such a path.
+ *)
+let qemu_input_filename filename +  if String.length filename > 0 &&
filename.[0] <> '/' then
+    "./" ^ filename
+  else
+    filename
diff --git a/mllib/common_utils.mli b/mllib/common_utils.mli
index 2103ff1..e59d802 100644
--- a/mllib/common_utils.mli
+++ b/mllib/common_utils.mli
@@ -131,3 +131,11 @@ val is_directory : string -> bool
 
 val absolute_path : string -> string
 (** Convert any path to an absolute path. *)
+
+val qemu_input_filename : string -> string
+(** Sanitizes a filename for passing it safely to qemu/qemu-img.
+
+    If the filename is something like "file:foo" then qemu-img will
+    try to interpret that as "foo" in the file:/// protocol.  To
+    avoid that, if the path is relative prefix it with "./" since
+    qemu-img won't try to interpret such a path. *)
-- 
1.9.3

With commit a594b7f90a682e2a9327b142138edb76ad8ba8ff the checks for
input and output files with ':' were removed; while the input file is
handled correctly by the disk_create API, an output filename with ':'
could still be handled as specifying a transport, failing the last
"qemu-img convert" call.

Use the new qemu_input_filename helper to handle the output filename
correctly.
---
 sparsify/copying.ml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sparsify/copying.ml b/sparsify/copying.ml
index 3628b01..d4861f9 100644
--- a/sparsify/copying.ml
+++ b/sparsify/copying.ml
@@ -311,7 +311,7 @@ You can ignore this warning or change it to a hard failure
using the
       (match option with
       | None -> ""
       | Some option -> " -o " ^ quote option)
-      (quote overlaydisk) (quote outdisk) in
+      (quote overlaydisk) (quote (qemu_input_filename outdisk)) in
   if verbose then
     printf "%s\n%!" cmd;
   if Sys.command cmd <> 0 then
-- 
1.9.3

On Fri, Jan 16, 2015 at 07:33:20PM +0100, Pino Toscano
wrote:
> With commit a594b7f90a682e2a9327b142138edb76ad8ba8ff the checks for
> input and output files with ':' were removed; while the input file
is
> handled correctly by the disk_create API, an output filename with
':'
> could still be handled as specifying a transport, failing the last
> "qemu-img convert" call.
> 
> Use the new qemu_input_filename helper to handle the output filename
> correctly.
> ---
>  sparsify/copying.ml | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/sparsify/copying.ml b/sparsify/copying.ml
> index 3628b01..d4861f9 100644
> --- a/sparsify/copying.ml
> +++ b/sparsify/copying.ml
> @@ -311,7 +311,7 @@ You can ignore this warning or change it to a hard
failure using the
>        (match option with
>        | None -> ""
>        | Some option -> " -o " ^ quote option)
> -      (quote overlaydisk) (quote outdisk) in
> +      (quote overlaydisk) (quote (qemu_input_filename outdisk)) in
>    if verbose then
>      printf "%s\n%!" cmd;
>    if Sys.command cmd <> 0 then
ACK both.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
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