[sqlite] cd rather than symlink db paths

Summary: Reuse technique originally for unix sockets: cd into the directory with the database file, open it, then cd back. This avoids the Sqlite limits on maximum path length entirely.

Reviewed By: jvillard

Differential Revision:
D66544844

Privacy Context Container: L1208441

fbshipit-source-id: 66d05cee5c85bc41c7f8fa5404dbefdc741fb4e9

infer/src/base/Database.ml

@@ -138,39 +138,28 @@ type location = Primary | Secondary of string [@@deriving show {with_path= false
 let results_dir_get_path entry = ResultsDirEntryName.get_path ~results_dir:Config.results_dir entry
 
 let get_db_path location id =
-  match location with
-  | Secondary file ->
-      file
-  | Primary ->
-      let path_to_db = results_dir_get_path (get_db_entry id) in
-      if String.length path_to_db > SqliteUtils.sqlite_max_path_length then (
-        let link_name = Filename.temp_file "infer-merge-sqlite-trampoline" ".db" in
-        Unix.unlink link_name ;
-        Unix.symlink ~target:(Filename.dirname path_to_db) ~link_name ;
-        Filename.concat link_name (Filename.basename path_to_db) )
-      else path_to_db
+  match location with Secondary file -> file | Primary -> results_dir_get_path (get_db_entry id)
+
+
+let do_in_db_dir db_path ~f =
+  let dir = Filename.dirname db_path in
+  let base_name = Filename.basename db_path in
+  Utils.do_in_dir ~dir ~f:(fun () -> f base_name)
 
 
 let create_db location id =
   let final_db_path = get_db_path location id in
   let pid = Unix.getpid () in
-  let in_dir =
-    (* if the length of the path to the results directory is greater than Sqlite's limit
-       then create the DB in [$TMPDIR] otherwise in [results_dir/tmp] *)
-    let results_temp_dir = results_dir_get_path Temporary in
-    if String.length results_temp_dir > SqliteUtils.sqlite_max_path_length - 50 then None
-    else Some results_temp_dir
-  in
   let temp_db_path =
-    Filename.temp_file ?in_dir
+    Filename.temp_file ~in_dir:(results_dir_get_path Temporary)
       ( match id with
       | CaptureDatabase ->
           "capture." ^ Pid.to_string pid ^ ".db"
       | AnalysisDatabase ->
           "results." ^ Pid.to_string pid ^ ".db" )
       ".tmp"
   in
-  let db = Sqlite3.db_open ~mutex:`FULL temp_db_path in
+  let db = do_in_db_dir temp_db_path ~f:(fun db_path -> Sqlite3.db_open ~mutex:`FULL db_path) in
   SqliteUtils.exec db ~log:"sqlite page size"
     ~stmt:(Printf.sprintf "PRAGMA page_size=%d" Config.sqlite_page_size) ;
   create_tables db id ;
@@ -315,8 +304,9 @@ end = struct
     db_close_1 id ;
     let db_path = get_db_path location id in
     let db =
-      Sqlite3.db_open ~mode:`NO_CREATE ~cache:`PRIVATE ~mutex:`FULL ?vfs:Config.sqlite_vfs ~uri:true
-        db_path
+      do_in_db_dir db_path ~f:(fun db_path ->
+          Sqlite3.db_open ~mode:`NO_CREATE ~cache:`PRIVATE ~mutex:`FULL ?vfs:Config.sqlite_vfs
+            ~uri:true db_path )
     in
     Sqlite3.busy_timeout db Config.sqlite_lock_timeout ;
     SqliteUtils.exec db ~log:"mmap"

infer/src/base/SqliteUtils.mli

@@ -14,9 +14,6 @@ exception Error of string
 (** Raised from serializers when final size exceeds Sqlite3 limits (normally 1000_000_000 bytes). *)
 exception DataTooBig
 
-val sqlite_max_path_length : int
-(** an underapproximation of the maximum path length allowed in sqlite *)
-
 val check_result_code : Sqlite3.db -> log:string -> Sqlite3.Rc.t -> unit
 (** Assert that the result is either [Sqlite3.Rc.OK] or [Sqlite3.Rc.ROW]. If the result is not
     valid, raise {!Error}. *)