CP-52074: Add systemctl enable and disable API

Signed-off-by: Bengang Yuan <[email protected]>

ocaml/forkexecd/lib/fe_systemctl.ml

@@ -121,15 +121,19 @@ let stop ~service =
   Xapi_stdext_unix.Unixext.unlink_safe destination ;
   status
 
-let is_active ~service =
+let check_service_status ~command ~service =
   let status =
     Forkhelpers.safe_close_and_exec None None None [] systemctl
-      ["is-active"; "--quiet"; service]
+      [command; "--quiet"; service]
     |> Forkhelpers.waitpid
     |> snd
   in
   Unix.WEXITED 0 = status
 
+let is_active ~service = check_service_status ~command:"is-active" ~service
+
+let is_enabled ~service = check_service_status ~command:"is-enabled" ~service
+
 (** path to service file *)
 let path service = Filename.concat run_path (service ^ ".service")
 

ocaml/forkexecd/lib/fe_systemctl.mli

@@ -45,6 +45,9 @@ val start_transient :
 val is_active : service:string -> bool
 (** [is_active ~service] checks whether the [service] is still running *)
 
+val is_enabled : service:string -> bool
+(** [is_enabled ~service] checks whether the [service] is enabled *)
+
 val show : service:string -> status
 (** [shows ~service] retrieves the exitcodes and PIDs of the specified [service] *)
 

ocaml/xapi/xapi_systemctl.ml

@@ -19,7 +19,7 @@ module D = Debug.Make (struct let name = "xapi_systemctl" end)
 
 open D
 
-type t = Start | Stop | Restart
+type t = Start | Stop | Restart | Enable | Disable
 
 exception Systemctl_fail of string
 
@@ -30,6 +30,10 @@ let to_string = function
       "stop"
   | Restart ->
       "restart"
+  | Enable ->
+      "enable"
+  | Disable ->
+      "disable"
 
 let perform ~wait_until_success ~service ~timeout op =
   let op_str = op |> to_string in
@@ -42,8 +46,17 @@ let perform ~wait_until_success ~service ~timeout op =
     if wait_until_success then (
       if op = Restart then Thread.delay 0.1 ;
       let is_active = Fe_systemctl.is_active ~service in
+      let is_enabled = Fe_systemctl.is_enabled ~service in
       let success_cond () =
-        match op with Start | Restart -> is_active | Stop -> is_active |> not
+        match op with
+        | Start | Restart ->
+            is_active
+        | Stop ->
+            is_active |> not
+        | Enable ->
+            is_enabled
+        | Disable ->
+            is_enabled |> not
       in
       try
         Helpers.retry_until_timeout ~timeout
@@ -66,3 +79,11 @@ let stop ?(timeout = 5.) ~wait_until_success service =
 
 let start ?(timeout = 5.) ~wait_until_success service =
   perform ~wait_until_success ~service ~timeout Start
+
+let disable ?(timeout = 5.) ~wait_until_success service =
+  if Fe_systemctl.is_enabled ~service:"sshd" then
+    perform ~wait_until_success ~service ~timeout Disable
+
+let enable ?(timeout = 5.) ~wait_until_success service =
+  if not (Fe_systemctl.is_enabled ~service:"sshd") then
+    perform ~wait_until_success ~service ~timeout Enable

ocaml/xapi/xapi_systemctl.mli

@@ -15,6 +15,10 @@
 (* Exception about systemctl operation like start/stop failed *)
 exception Systemctl_fail of string
 
+type t = Start | Stop | Restart | Enable | Disable
+
+val to_string : t -> string
+
 (* start a service with systemctl *)
 val start : ?timeout:float -> wait_until_success:bool -> string -> unit
 
@@ -23,3 +27,9 @@ val stop : ?timeout:float -> wait_until_success:bool -> string -> unit
 
 (* restart a service with systemctl *)
 val restart : ?timeout:float -> wait_until_success:bool -> string -> unit
+
+(* enable a service with systemctl *)
+val enable : ?timeout:float -> wait_until_success:bool -> string -> unit
+
+(* disable a service with systemctl *)
+val disable : ?timeout:float -> wait_until_success:bool -> string -> unit