robur/opam-mirror
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Use GPT table

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For now we assume the presence of the GPT header and provide no way to
format such a disk image. WIP.
This commit is contained in:
Reynir Björnsson 2024-03-21 16:19:19 +01:00
parent e002bf8730
commit 0c6482eb70
2 changed files with 77 additions and 9 deletions
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2
mirage/config.ml
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@ -82,6 +82,8 @@ let mirror =
package ~min:"2.2.0" ~sublibs:[ "gz" ] "tar" ;
package ~min:"2.2.0" "tar-mirage" ;
package ~max:"0.2.0" "mirage-block-partition" ;
package "gpt" ;
package "gptar" ~pin:"git+https://github.com/reynir/gptar.git" ;
package "oneffs" ;
]
(block @-> time @-> pclock @-> stackv4v6 @-> git_client @-> alpn_client @-> job)

84
mirage/unikernel.ml
View file

@ -1031,17 +1031,83 @@ stamp: %S
module Paf = Paf_mirage.Make(Stack.TCP)
let read_partition_table info block =
let b = Cstruct.create info.Mirage_block.sector_size in
(* We will ignore the protective MBR at lba [0L] *)
BLOCK.read block 1L [b] >>= fun r ->
match r with
| Error e ->
Format.kasprintf failwith "Reading partition table: %a"
BLOCK.pp_error e
| Ok () ->
match Gpt.unmarshal b ~sector_size:info.Mirage_block.sector_size with
| Error e ->
Format.kasprintf failwith "Reading partition table: %s" e
| Ok (`Read_partition_table (lba, sectors), k) ->
let b = Cstruct.create (sectors * info.Mirage_block.sector_size) in
BLOCK.read block lba [b] >>= fun r ->
match r with
| Error e ->
Format.kasprintf failwith "Reading partition table: %a"
BLOCK.pp_error e
| Ok () ->
match k b with
| Error e ->
Format.kasprintf failwith "Reading partition table: %s" e
| Ok gpt -> Lwt.return gpt
let get_partitions info block =
let utf16be_of_ascii s =
String.init 72
(fun i ->
if i mod 2 = 0 && i / 2 < String.length s then
s.[i/2]
else
'\000')
in
read_partition_table info block >>= fun gpt ->
let tar, git_dump, md5s, sha512s =
match
List.fold_left
(fun (tar, git_dump, md5s, sha512s) p ->
if String.equal p.Gpt.Partition.name
(utf16be_of_ascii "tar")
then
(Some p, git_dump, md5s, sha512s)
else if String.equal p.name
(utf16be_of_ascii "git_dump")
then
(tar, Some p, md5s, sha512s)
else if String.equal p.name
(utf16be_of_ascii "md5s")
then
(tar, git_dump, Some p, sha512s)
else if String.equal p.name
(utf16be_of_ascii "sha512s")
then
(tar, git_dump, md5s, Some p)
else
Format.kasprintf failwith "Unknown partition %S" p.name)
(None, None, None, None)
gpt.partitions
with
| (Some tar, Some git_dump, Some md5s, Some sha512s) ->
(tar, git_dump, md5s, sha512s)
| _ ->
failwith "not all partitions found :("
in
Part.connect 0L block >>= fun (_empty, p) ->
let get_part part =
let len = Int64.(succ (sub part.Gpt.Partition.ending_lba part.starting_lba)) in
let (_before, after) = Part.subpartition part.starting_lba p in
let (part, _after) = Part.subpartition len after in
part
in
Lwt.return (get_part tar, get_part git_dump, get_part md5s, get_part sha512s)
let start block _time _pclock stack git_ctx http_ctx =
BLOCK.get_info block >>= fun info ->
let sectors_cache = Key_gen.sectors_cache () in
let sectors_git = Key_gen.sectors_git () in
let git_start =
let cache_size = Int64.(mul 2L sectors_cache) in
Int64.(sub info.size_sectors (add cache_size sectors_git))
in
Part.connect git_start block >>= fun (kv, rest) ->
let git_dump, rest = Part.subpartition sectors_git rest in
let md5s, sha512s = Part.subpartition sectors_cache rest in
get_partitions info block >>= fun (kv, git_dump, md5s, sha512s) ->
KV.connect kv >>= fun kv ->
Cache.connect md5s >>= fun md5s ->
Cache.connect sha512s >>= fun sha512s ->