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(*
* Copyright (c) 2017-present, Facebook, Inc.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*)
open! IStd
module F = Format
module L = Logging
module Domain = ResourceLeakDomain
(* Boilerplate to write/read our summaries alongside the summaries of other analyzers *)
module Payload = SummaryPayload.Make (struct
type t = Domain.astate
let update_payloads resources_payload (payloads : Payloads.t) =
{payloads with resources= Some resources_payload}
let of_payloads (payloads : Payloads.t) = payloads.resources
end)
type extras = FormalMap.t
module TransferFunctions (CFG : ProcCfg.S) = struct
module CFG = CFG
module Domain = Domain
type nonrec extras = extras
(* Take an abstract state and instruction, produce a new abstract state *)
let exec_instr (astate : Domain.astate) {ProcData.pdesc; tenv} _ (instr : HilInstr.t) =
let is_closeable procname tenv =
match procname with
| Typ.Procname.Java java_procname ->
let is_closable_interface typename _ =
match Typ.Name.name typename with
| "java.io.AutoCloseable" | "java.io.Closeable" ->
true
| _ ->
false
in
PatternMatch.supertype_exists tenv is_closable_interface
(Typ.Name.Java.from_string (Typ.Procname.Java.get_class_name java_procname))
| _ ->
false
in
(* We assume all constructors of a subclass of Closeable acquire a resource *)
let acquires_resource procname tenv =
Typ.Procname.is_constructor procname && is_closeable procname tenv
in
(* We assume the close method of a Closeable releases all of its resources *)
let releases_resource procname tenv =
match Typ.Procname.get_method procname with
| "close" ->
is_closeable procname tenv
| _ ->
false
in
match instr with
| Call (_return_opt, Direct callee_procname, _actuals, _, _loc) -> (
(* function call [return_opt] := invoke [callee_procname]([actuals]) *)
(* 1(e) *)
let astate' =
if acquires_resource callee_procname tenv then astate + 1 (* 2(a) *)
else if releases_resource callee_procname tenv then astate - 1 (* 2(a) *)
else astate
in
match Payload.read pdesc callee_procname with
| Some _summary ->
(* Looked up the summary for callee_procname... do something with it *)
(* 4(a) *)
(* 5(b) *)
astate'
| None ->
(* No summary for callee_procname; it's native code or missing for some reason *)
astate' )
| Assign (_lhs_access_path, _rhs_exp, _loc) ->
(* an assignment [lhs_access_path] := [rhs_exp] *)
astate
| Assume (_assume_exp, _, _, _loc) ->
(* a conditional assume([assume_exp]). blocks if [assume_exp] evaluates to false *)
astate
| Call (_, Indirect _, _, _, _) ->
(* This should never happen in Java. Fail if it does. *)
L.(die InternalError) "Unexpected indirect call %a" HilInstr.pp instr
let pp_session_name _node fmt = F.pp_print_string fmt "resource leaks"
end
(* Create an intraprocedural abstract interpreter from the transfer functions we defined *)
module Analyzer =
LowerHil.MakeAbstractInterpreter
(* Type of CFG to analyze--Exceptional to follow exceptional control-flow edges, Normal to
ignore them *)
(ProcCfg.Normal)
(* 5(a) *)
(TransferFunctions)
(* Callback for invoking the checker from the outside--registered in RegisterCheckers *)
let checker {Callbacks.summary; proc_desc; tenv} : Summary.t =
(* Report an error when we have acquired more resources than we have released *)
let report leak_count (proc_data : extras ProcData.t) =
if leak_count > 0 (* 2(a) *) then
let last_loc = Procdesc.Node.get_loc (Procdesc.get_exit_node proc_data.pdesc) in
let message = F.asprintf "Leaked %d resource(s)" leak_count in
Reporting.log_error summary ~loc:last_loc IssueType.resource_leak message
in
(* Convert the abstract state to a summary. for now, just the identity function *)
let convert_to_summary (post : Domain.astate) : Domain.summary =
(* 4(a) *)
post
in
let extras = FormalMap.make proc_desc in
let proc_data = ProcData.make proc_desc tenv extras in
match Analyzer.compute_post proc_data ~initial:ResourceLeakDomain.initial with
| Some post ->
(* 1(f) *)
report post proc_data ;
Payload.update_summary (convert_to_summary post) summary
| None ->
L.(die InternalError)
"Analyzer failed to compute post for %a" Typ.Procname.pp
(Procdesc.get_proc_name proc_data.pdesc)