Mailing List Archive

[PATCH v1 4/5] tools/ocaml/xenstored: add support for binary format
Signed-off-by: Edwin Török <edvin.torok@citrix.com>
---
tools/ocaml/xenstored/perms.ml | 2 +
tools/ocaml/xenstored/xenstored.ml | 201 ++++++++++++++++++++++++-----
2 files changed, 173 insertions(+), 30 deletions(-)

diff --git a/tools/ocaml/xenstored/perms.ml b/tools/ocaml/xenstored/perms.ml
index e8a16221f8..61c1c60083 100644
--- a/tools/ocaml/xenstored/perms.ml
+++ b/tools/ocaml/xenstored/perms.ml
@@ -69,6 +69,8 @@ let remove_domid ~domid perm =

let default0 = create 0 NONE []

+let acls t = (t.owner, t.other) :: t.acl
+
let perm_of_string s =
let ty = permty_of_char s.[0]
and id = int_of_string (String.sub s 1 (String.length s - 1)) in
diff --git a/tools/ocaml/xenstored/xenstored.ml b/tools/ocaml/xenstored/xenstored.ml
index e25b407303..9338190804 100644
--- a/tools/ocaml/xenstored/xenstored.ml
+++ b/tools/ocaml/xenstored/xenstored.ml
@@ -141,7 +141,8 @@ exception Bad_format of string

let dump_format_header = "$xenstored-dump-format"

-let from_channel_f chan global_f socket_f domain_f watch_f store_f =
+(* for backwards compatibility with already released live-update *)
+let from_channel_f_compat chan global_f socket_f domain_f watch_f store_f =
let unhexify s = Utils.unhexify s in
let getpath s =
let u = Utils.unhexify s in
@@ -186,7 +187,7 @@ let from_channel_f chan global_f socket_f domain_f watch_f store_f =
done;
info "Completed loading xenstore dump"

-let from_channel store cons doms chan =
+let from_channel_compat ~live store cons doms chan =
(* don't let the permission get on our way, full perm ! *)
let op = Store.get_ops store Perms.Connection.full_rights in
let rwro = ref (None) in
@@ -226,43 +227,183 @@ let from_channel store cons doms chan =
op.Store.write path value;
op.Store.setperms path perms
in
- from_channel_f chan global_f socket_f domain_f watch_f store_f;
+ from_channel_f_compat chan global_f socket_f domain_f watch_f store_f;
!rwro

-let from_file store cons doms file =
- info "Loading xenstore dump from %s" file;
- let channel = open_in file in
- finally (fun () -> from_channel store doms cons channel)
+module LR = Disk.LiveRecord
+
+let from_channel_f_bin chan on_global_data on_connection_data on_watch_data on_transaction_data on_node_data =
+ Disk.BinaryIn.read_header chan;
+ let quit = ref false in
+ let on_end () = quit := true in
+ let errors = ref 0 in
+ while not !quit
+ do
+ try
+ LR.read_record chan ~on_end ~on_global_data ~on_connection_data ~on_watch_data ~on_transaction_data ~on_node_data
+ with exn ->
+ let bt = Printexc.get_backtrace () in
+ incr errors;
+ Logging.warn "xenstored" "restoring: ignoring faulty record (exception: %s): %s" (Printexc.to_string exn) bt
+ done;
+ info "Completed loading xenstore dump";
+ !errors
+
+
+let from_channel_bin ~live store cons doms chan =
+ (* don't let the permission get on our way, full perm ! *)
+ let maintx = Transaction.make ~internal:true Transaction.none store in
+ let fullperm = Perms.Connection.full_rights in
+ let fds = ref None in
+ let allcons = Hashtbl.create 1021 in
+ let contxid_to_op = Hashtbl.create 1021 in
+ let global_f ~rw_sock =
+ (* file descriptors are only valid on a live-reload, a cold restart won't have them *)
+ if live then
+ fds := Some rw_sock
+ in
+ let domain_f ~conid ~conn ~in_data ~out_data ~out_resp_len =
+ let con = match conn with
+ | LR.Domain { LR.id = 0; _ } ->
+ (* Dom0 is precreated *)
+ Connections.find_domain cons 0
+ | LR.Domain d ->
+ debug "Recreating domain %d, port %d" d.id d.remote_port;
+ (* FIXME: gnttab *)
+ Domains.create doms d.id 0n d.remote_port
+ |> Connections.add_domain cons;
+ Connections.find_domain cons d.id
+ | LR.Socket fd ->
+ debug "Recreating open socket";
+ (* TODO: rw/ro flag *)
+ Connections.add_anonymous cons fd;
+ Connections.find cons fd
+ in
+ Hashtbl.add allcons conid con
+ in
+ let watch_f ~conid ~wpath ~token =
+ let con = Hashtbl.find allcons conid in
+ ignore (Connections.add_watch cons con wpath token);
+ ()
+ in
+ let transaction_f ~conid ~txid =
+ let con = Hashtbl.find allcons conid in
+ con.Connection.next_tid <- txid;
+ let id = Connection.start_transaction con store in
+ assert (id = txid);
+ let txn = Connection.get_transaction con txid in
+ Hashtbl.add contxid_to_op (conid, txid) txn
+ in
+ let store_f ~txaccess ~perms ~path ~value =
+ let txn, op = match txaccess with
+ | None -> maintx, LR.W
+ | Some (conid, txid, op) ->
+ let (txn, _) as r = Hashtbl.find contxid_to_op (conid, txid), op in
+ (* make sure this doesn't commit, even as RO *)
+ Transaction.mark_failed txn;
+ r
+ in
+ let get_con id =
+ if id < 0 then Connections.find cons (Utils.FD.of_int (-id))
+ else Connections.find_domain cons id
+ in
+ let watch_f id path token =
+ ignore (Connections.add_watch cons (get_con id) path token)
+ in
+ let path = Store.Path.of_string path in
+ try match op with
+ | LR.R ->
+ Logging.debug "xenstored" "TR %s %S" (Store.Path.to_string path) value;
+ (* these are values read by the tx, potentially
+ no write access here. Make the tree match. *)
+ Transaction.write txn fullperm path value;
+ Transaction.setperms txn fullperm path perms;
+ | LR.W | LR.RW ->
+ Logging.debug "xenstored" "TW %d %s %S" (Transaction.get_id txn) (Store.Path.to_string path) value;
+ (* We started with empty tree, create parents.
+ All the implicit mkdirs from the original tx should be explicit already for quota purposes.
+ *)
+ Process.create_implicit_path txn fullperm path;
+ Transaction.write txn fullperm path value;
+ Transaction.setperms txn fullperm path perms;
+ Logging.debug "xenstored" "TWdone %s %S" (Store.Path.to_string path) value;
+ | LR.Del ->
+ Logging.debug "xenstored" "TDel %s " (Store.Path.to_string path);
+ Transaction.rm txn fullperm path
+ with Not_found|Define.Doesnt_exist|Define.Lookup_Doesnt_exist _ -> ()
+ in
+ (* make sure we got a quota entry for Dom0, so that setperms on / doesn't cause quota to be off-by-one *)
+ Transaction.mkdir maintx fullperm (Store.Path.of_string "/local");
+ let errors = from_channel_f_bin chan global_f domain_f watch_f transaction_f store_f in
+ (* do not fire any watches, but this makes a tx RO *)
+(* Transaction.clear_wops maintx; *)
+ let errors = if not @@ Transaction.commit ~con:"live-update" maintx then begin
+ Logging.warn "xenstored" "live-update: failed to commit main transaction";
+ errors + 1
+ end else errors
+ in
+ !fds, errors
+
+let from_channel = from_channel_bin (* TODO: detect and accept text format *)
+
+let from_file ~live store cons doms file =
+ let channel = open_in_bin file in
+ finally (fun () -> from_channel_bin ~live store doms cons channel)
(fun () -> close_in channel)

-let to_channel store cons rw chan =
- let hexify s = Utils.hexify s in
+let to_channel rw_sock store cons chan =
+ let t = Disk.BinaryOut.write_header chan in

- fprintf chan "%s\n" dump_format_header;
- let fdopt = function None -> -1 | Some fd ->
- (* systemd and utils.ml sets it close on exec *)
- Unix.clear_close_on_exec fd;
- Utils.FD.to_int fd in
- fprintf chan "global,%d\n" (fdopt rw);
-
- (* dump connections related to domains: domid, mfn, eventchn port/ sockets, and watches *)
- Connections.iter cons (fun con -> Connection.dump con chan);
+ (match rw_sock with
+ | Some rw_sock ->
+ LR.write_global_data t ~rw_sock
+ | _ -> ());

(* dump the store *)
Store.dump_fct store (fun path node ->
- let name, perms, value = Store.Node.unpack node in
- let fullpath = Store.Path.to_string (Store.Path.of_path_and_name path name) in
- let permstr = Perms.Node.to_string perms in
- fprintf chan "store,%s,%s,%s\n" (hexify fullpath) (hexify permstr) (hexify value)
+ Transaction.write_node t None path node
);
+
+ (* dump connections related to domains and sockets; domid, mfn, eventchn port, watches *)
+ Connections.iter cons (fun con -> Connection.dump con store t);
+
+ LR.write_end t;
flush chan;
()

+let validate_f ch =
+ let conids = Hashtbl.create 1021 in
+ let txids = Hashtbl.create 1021 in
+ let global_f ~rw_sock = () in
+ let domain_f ~conid ~conn ~in_data ~out_data ~out_resp_len =
+ Hashtbl.add conids conid ()
+ in
+ let watch_f ~conid ~wpath ~token =
+ Hashtbl.find conids conid
+ in
+ let transaction_f ~conid ~txid =
+ Hashtbl.find conids conid;
+ Hashtbl.add txids (conid, txid) ()
+ in
+ let store_f ~txaccess ~perms ~path ~value =
+ match txaccess with
+ | None -> ()
+ | Some (conid, txid, _) ->
+ Hashtbl.find conids conid;
+ Hashtbl.find txids (conid, txid)
+ in
+ let errors = from_channel_f_bin ch global_f domain_f watch_f transaction_f store_f in
+ if errors > 0 then
+ failwith (Printf.sprintf "Failed to re-read dump: %d errors" errors)

-let to_file store cons fds file =
- let channel = open_out_gen [ Open_wronly; Open_creat; Open_trunc; ] 0o600 file in
- finally (fun () -> to_channel store cons fds channel)
- (fun () -> close_out channel)
+let to_file fds store cons file =
+ let channel = open_out_gen [ Open_wronly; Open_creat; Open_trunc; Open_binary ] 0o600 file in
+ finally (fun () -> to_channel fds store cons channel)
+ (fun () -> close_out channel);
+ let channel = open_in_bin file in
+ finally (fun () -> validate_f channel)
+ (fun () -> close_in channel)
+
end

let main () =
@@ -329,8 +470,8 @@ let main () =

let rw_sock =
if cf.restart && Sys.file_exists Disk.xs_daemon_database then (
- let rwro = DB.from_file store domains cons Disk.xs_daemon_database in
- info "Live reload: database loaded";
+ let rwro, errors = DB.from_file ~live:cf.live_reload store domains cons Disk.xs_daemon_database in
+ info "Live reload: database loaded (%d errors)" errors;
Event.bind_dom_exc_virq eventchn;
Process.LiveUpdate.completed ();
rwro
@@ -367,7 +508,7 @@ let main () =
Sys.set_signal Sys.sigpipe Sys.Signal_ignore;

if cf.activate_access_log then begin
- let post_rotate () = DB.to_file store cons (None) Disk.xs_daemon_database in
+ let post_rotate () = DB.to_file None store cons Disk.xs_daemon_database in
Logging.init_access_log post_rotate
end;

@@ -528,7 +669,7 @@ let main () =
live_update := Process.LiveUpdate.should_run cons;
if !live_update || !quit then begin
(* don't initiate live update if saving state fails *)
- DB.to_file store cons (rw_sock) Disk.xs_daemon_database;
+ DB.to_file rw_sock store cons Disk.xs_daemon_database;
quit := true;
end
with exc ->
--
2.29.2