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libguestfs/daemon/parted.ml
2017-07-27 22:31:22 +01:00

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(* guestfs-inspection
* Copyright (C) 2009-2017 Red Hat Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*)
open Scanf
open Std_utils
open Utils
include Structs
(* Test if [sfdisk] is recent enough to have [--part-type], to be used
* instead of [--print-id] and [--change-id].
*)
let test_sfdisk_has_part_type = lazy (
let out = command "sfdisk" ["--help"] in
String.find out "--part-type" >= 0
)
(* Currently we use sfdisk for getting and setting the ID byte. In
* future, extend parted to provide this functionality. As a result
* of using sfdisk, this won't work for non-MBR-style partitions, but
* that limitation is noted in the documentation and we can extend it
* later without breaking the ABI.
*)
let part_get_mbr_id device partnum =
if partnum <= 0 then
failwith "partition number must be >= 1";
let param =
if Lazy.force test_sfdisk_has_part_type then
"--part-type"
else
"--print-id" in
udev_settle ();
let out =
command "sfdisk" [param; device; string_of_int partnum] in
udev_settle ();
(* It's printed in hex, possibly with a leading space. *)
sscanf out " %x" identity
(* This is not equivalent to print_partition_table in the C code, as
* it only deals with the -m option output, and it partially parses
* that. If we convert other functions that don't use the -m version
* we'll have to refactor this. XXX
*)
let print_partition_table_machine_readable device =
udev_settle ();
let args = ref [] in
push_back args "-m";
push_back args "-s";
push_back args "--";
push_back args device;
push_back args "unit";
push_back args "b";
push_back args "print";
let out =
try command "parted" !args
with
(* Translate "unrecognised disk label" into an errno code. *)
Failure str when String.find str "unrecognised disk label" >= 0 ->
raise (Unix.Unix_error (Unix.EINVAL, "parted", device ^ ": " ^ str)) in
udev_settle ();
(* Split the output into lines. *)
let out = String.trim out in
let lines = String.nsplit "\n" out in
(* lines[0] is "BYT;", lines[1] is the device line which we ignore,
* lines[2..] are the partitions themselves.
*)
match lines with
| "BYT;" :: _ :: lines -> lines
| [] | [_] ->
failwith "too few rows of output from 'parted print' command"
| _ ->
failwith "did not see 'BYT;' magic value in 'parted print' command"
let part_list device =
let lines = print_partition_table_machine_readable device in
List.map (
fun line ->
try sscanf line "%d:%LdB:%LdB:%LdB"
(fun num start end_ size ->
{ part_num = Int32.of_int num;
part_start = start; part_end = end_; part_size = size })
with Scan_failure err ->
failwithf "could not parse row from output of 'parted print' command: %s: %s"
line err
) lines