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|
(* Example showing how to create a disk image. *)
open Unix
open Printf
let output = "disk.img"
let () =
let g = new Guestfs.guestfs () in
(* Create a raw-format sparse disk image, 512 MB in size. *)
let fd = openfile output [O_WRONLY;O_CREAT;O_TRUNC;O_NOCTTY] 0o666 in
ftruncate fd (512 * 1024 * 1024);
close fd;
(* Set the trace flag so that we can see each libguestfs call. *)
g#set_trace true;
(* Set the autosync flag so that the disk will be synchronized
* automatically when the libguestfs handle is closed.
*)
g#set_autosync true;
(* Attach the disk image to libguestfs. *)
g#add_drive_opts ~format:"raw" ~readonly:false output;
(* Run the libguestfs back-end. *)
g#launch ();
(* Get the list of devices. Because we only added one drive
* above, we expect that this list should contain a single
* element.
*)
let devices = g#list_devices () in
if Array.length devices <> 1 then
failwith "error: expected a single device from list-devices";
(* Partition the disk as one single MBR partition. *)
g#part_disk devices.(0) "mbr";
(* Get the list of partitions. We expect a single element, which
* is the partition we have just created.
*)
let partitions = g#list_partitions () in
if Array.length partitions <> 1 then
failwith "error: expected a single partition from list-partitions";
(* Create a filesystem on the partition. *)
g#mkfs "ext4" partitions.(0);
(* Now mount the filesystem so that we can add files. *)
g#mount_options "" partitions.(0) "/";
(* Create some files and directories. *)
g#touch "/empty";
let message = "Hello, world\n" in
g#write "/hello" message;
g#mkdir "/foo";
(* This one uploads the local file /etc/resolv.conf into
* the disk image.
*)
g#upload "/etc/resolv.conf" "/foo/resolv.conf";
(* Because 'autosync' was set (above) we can just close the handle
* and the disk contents will be synchronized. You can also do
* this manually by calling g#umount_all and g#sync.
*
* Note also that handles are automatically closed if they are
* reaped by the garbage collector. You only need to call close
* if you want to close the handle right away.
*)
g#close ()
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