------------------------------------------------------------------------------ -- -- -- GNAT RUN-TIME COMPONENTS -- -- -- -- S Y S T E M . T R A C E B A C K . S Y M B O L I C -- -- -- -- B o d y -- -- -- -- Copyright (C) 1999-2018, AdaCore -- -- -- -- GNAT is free software; you can redistribute it and/or modify it under -- -- terms of the GNU General Public License as published by the Free Soft- -- -- ware Foundation; either version 3, or (at your option) any later ver- -- -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- -- or FITNESS FOR A PARTICULAR PURPOSE. -- -- -- -- As a special exception under Section 7 of GPL version 3, you are granted -- -- additional permissions described in the GCC Runtime Library Exception, -- -- version 3.1, as published by the Free Software Foundation. -- -- -- -- You should have received a copy of the GNU General Public License and -- -- a copy of the GCC Runtime Library Exception along with this program; -- -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- -- . -- -- -- -- GNAT was originally developed by the GNAT team at New York University. -- -- Extensive contributions were provided by Ada Core Technologies Inc. -- -- -- ------------------------------------------------------------------------------ -- Run-time symbolic traceback support for targets using DWARF debug data pragma Polling (Off); -- We must turn polling off for this unit, because otherwise we can get -- elaboration circularities when polling is turned on. with Ada.Unchecked_Deallocation; with Ada.Exceptions.Traceback; use Ada.Exceptions.Traceback; with Ada.Containers.Generic_Array_Sort; with System.Address_To_Access_Conversions; with System.Soft_Links; with System.CRTL; with System.Dwarf_Lines; with System.Exception_Traces; with System.Standard_Library; with System.Traceback_Entries; with System.Strings; with System.Bounded_Strings; package body System.Traceback.Symbolic is use System.Bounded_Strings; use System.Dwarf_Lines; subtype Big_String is String (Positive); -- To deal with C strings package Big_String_Conv is new System.Address_To_Access_Conversions (Big_String); type Module_Cache; type Module_Cache_Acc is access all Module_Cache; type Module_Cache is record Name : Strings.String_Access; -- Name of the module C : Dwarf_Context (In_Exception => True); -- Context to symbolize an address within this module Chain : Module_Cache_Acc; end record; procedure Free is new Ada.Unchecked_Deallocation (Module_Cache, Module_Cache_Acc); Cache_Chain : Module_Cache_Acc; -- Simply linked list of modules type Module_Array is array (Natural range <>) of Module_Cache_Acc; type Module_Array_Acc is access Module_Array; Modules_Cache : Module_Array_Acc; -- Sorted array of cached modules (if not null) Exec_Module : aliased Module_Cache; -- Context for the executable type Init_State is (Uninitialized, Initialized, Failed); Exec_Module_State : Init_State := Uninitialized; -- How Exec_Module is initialized procedure Init_Exec_Module; -- Initialize Exec_Module if not already initialized function Symbolic_Traceback (Traceback : System.Traceback_Entries.Tracebacks_Array; Suppress_Hex : Boolean) return String; function Symbolic_Traceback (E : Ada.Exceptions.Exception_Occurrence; Suppress_Hex : Boolean) return String; -- Suppress_Hex means do not print any hexadecimal addresses, even if the -- symbol is not available. function Lt (Left, Right : Module_Cache_Acc) return Boolean; -- Sort function for Module_Cache procedure Init_Module (Module : out Module_Cache; Success : out Boolean; Module_Name : String; Load_Address : Address := Null_Address); -- Initialize Module procedure Close_Module (Module : in out Module_Cache); -- Finalize Module function Value (Item : System.Address) return String; -- Return the String contained in Item, up until the first NUL character pragma Warnings (Off, "*Add_Module_To_Cache*"); procedure Add_Module_To_Cache (Module_Name : String; Load_Address : System.Address); -- To be called by Build_Cache_For_All_Modules to add a new module to the -- list. May not be referenced. package Module_Name is procedure Build_Cache_For_All_Modules; -- Create the cache for all current modules function Get (Addr : System.Address; Load_Addr : access System.Address) return String; -- Returns the module name for the given address Addr, or an empty -- string for the main executable. Load_Addr is set to the shared -- library load address if this information is available, or to -- System.Null_Address otherwise. function Is_Supported return Boolean; pragma Inline (Is_Supported); -- Returns True if Module_Name is supported, so if the traceback is -- supported for shared libraries. end Module_Name; package body Module_Name is separate; function Executable_Name return String; -- Returns the executable name as reported by argv[0]. If gnat_argv not -- initialized, return an empty string. If the argv[0] executable is not -- found in the PATH, return it unresolved. function Get_Executable_Load_Address return System.Address; pragma Import (C, Get_Executable_Load_Address, "__gnat_get_executable_load_address"); -- Get the load address of the executable, or Null_Address if not known procedure Hexa_Traceback (Traceback : Tracebacks_Array; Suppress_Hex : Boolean; Res : in out Bounded_String); -- Non-symbolic traceback (simply write addresses in hexa) procedure Symbolic_Traceback_No_Lock (Traceback : Tracebacks_Array; Suppress_Hex : Boolean; Res : in out Bounded_String); -- Like the public Symbolic_Traceback_No_Lock except there is no provision -- against concurrent accesses. procedure Module_Symbolic_Traceback (Traceback : Tracebacks_Array; Module : Module_Cache; Suppress_Hex : Boolean; Res : in out Bounded_String); -- Returns the Traceback for a given module procedure Multi_Module_Symbolic_Traceback (Traceback : Tracebacks_Array; Suppress_Hex : Boolean; Res : in out Bounded_String); -- Build string containing symbolic traceback for the given call chain procedure Multi_Module_Symbolic_Traceback (Traceback : Tracebacks_Array; Module : Module_Cache; Suppress_Hex : Boolean; Res : in out Bounded_String); -- Likewise but using Module Max_String_Length : constant := 4096; -- Arbitrary limit on Bounded_Str length ----------- -- Value -- ----------- function Value (Item : System.Address) return String is begin if Item /= Null_Address then for J in Big_String'Range loop if Big_String_Conv.To_Pointer (Item) (J) = ASCII.NUL then return Big_String_Conv.To_Pointer (Item) (1 .. J - 1); end if; end loop; end if; return ""; end Value; ------------------------- -- Add_Module_To_Cache -- ------------------------- procedure Add_Module_To_Cache (Module_Name : String; Load_Address : System.Address) is Module : Module_Cache_Acc; Success : Boolean; begin Module := new Module_Cache; Init_Module (Module.all, Success, Module_Name, Load_Address); if not Success then Free (Module); return; end if; Module.Chain := Cache_Chain; Cache_Chain := Module; end Add_Module_To_Cache; ---------------------- -- Init_Exec_Module -- ---------------------- procedure Init_Exec_Module is begin if Exec_Module_State = Uninitialized then declare Exec_Path : constant String := Executable_Name; Exec_Load : constant Address := Get_Executable_Load_Address; Success : Boolean; begin Init_Module (Exec_Module, Success, Exec_Path, Exec_Load); if Success then Exec_Module_State := Initialized; else Exec_Module_State := Failed; end if; end; end if; end Init_Exec_Module; -------- -- Lt -- -------- function Lt (Left, Right : Module_Cache_Acc) return Boolean is begin return Low_Address (Left.C) < Low_Address (Right.C); end Lt; ----------------------------- -- Module_Cache_Array_Sort -- ----------------------------- procedure Module_Cache_Array_Sort is new Ada.Containers.Generic_Array_Sort (Natural, Module_Cache_Acc, Module_Array, Lt); ------------------ -- Enable_Cache -- ------------------ procedure Enable_Cache (Include_Modules : Boolean := False) is begin -- Can be called at most once if Cache_Chain /= null then return; end if; -- Add all modules Init_Exec_Module; if Exec_Module_State = Failed then raise Program_Error with "cannot enable cache, executable state initialization failed."; end if; Cache_Chain := Exec_Module'Access; if Include_Modules then Module_Name.Build_Cache_For_All_Modules; end if; -- Build and fill the array of modules declare Count : Natural; Module : Module_Cache_Acc; begin for Phase in 1 .. 2 loop Count := 0; Module := Cache_Chain; while Module /= null loop Count := Count + 1; if Phase = 1 then Enable_Cache (Module.C); else Modules_Cache (Count) := Module; end if; Module := Module.Chain; end loop; if Phase = 1 then Modules_Cache := new Module_Array (1 .. Count); end if; end loop; end; -- Sort the array Module_Cache_Array_Sort (Modules_Cache.all); end Enable_Cache; --------------------- -- Executable_Name -- --------------------- function Executable_Name return String is -- We have to import gnat_argv as an Address to match the type of -- gnat_argv in the binder generated file. Otherwise, we get spurious -- warnings about type mismatch when LTO is turned on. Gnat_Argv : System.Address; pragma Import (C, Gnat_Argv, "gnat_argv"); type Argv_Array is array (0 .. 0) of System.Address; package Conv is new System.Address_To_Access_Conversions (Argv_Array); function locate_exec_on_path (A : System.Address) return System.Address; pragma Import (C, locate_exec_on_path, "__gnat_locate_exec_on_path"); begin if Gnat_Argv = Null_Address then return ""; end if; -- See if we can resolve argv[0] to a full path (to a file that we will -- be able to open). If the resolution fails, we were probably spawned -- by an imprecise exec call, typically passing a mere file name as -- argv[0] for a program in the current directory with '.' not on PATH. -- Best we can do is fallback to argv[0] unchanged in this case. If we -- fail opening that downstream, we'll just bail out. declare Argv0 : constant System.Address := Conv.To_Pointer (Gnat_Argv) (0); Resolved_Argv0 : constant System.Address := locate_exec_on_path (Argv0); Exe_Argv : constant System.Address := (if Resolved_Argv0 /= System.Null_Address then Resolved_Argv0 else Argv0); Result : constant String := Value (Exe_Argv); begin -- The buffer returned by locate_exec_on_path was allocated using -- malloc and we should release this memory. if Resolved_Argv0 /= Null_Address then System.CRTL.free (Resolved_Argv0); end if; return Result; end; end Executable_Name; ------------------ -- Close_Module -- ------------------ procedure Close_Module (Module : in out Module_Cache) is begin Close (Module.C); Strings.Free (Module.Name); end Close_Module; ----------------- -- Init_Module -- ----------------- procedure Init_Module (Module : out Module_Cache; Success : out Boolean; Module_Name : String; Load_Address : Address := Null_Address) is begin -- Early return if the module is not known if Module_Name = "" then Success := False; return; end if; Open (Module_Name, Module.C, Success); -- If a module can't be opened just return now, we just cannot give more -- information in this case. if not Success then return; end if; Set_Load_Address (Module.C, Load_Address); Module.Name := new String'(Module_Name); end Init_Module; ------------------------------- -- Module_Symbolic_Traceback -- ------------------------------- procedure Module_Symbolic_Traceback (Traceback : Tracebacks_Array; Module : Module_Cache; Suppress_Hex : Boolean; Res : in out Bounded_String) is Success : Boolean := False; begin if Symbolic.Module_Name.Is_Supported then Append (Res, '['); Append (Res, Module.Name.all); Append (Res, ']' & ASCII.LF); end if; Dwarf_Lines.Symbolic_Traceback (Module.C, Traceback, Suppress_Hex, Success, Res); if not Success then Hexa_Traceback (Traceback, Suppress_Hex, Res); end if; -- We must not allow an unhandled exception here, since this function -- may be installed as a decorator for all automatic exceptions. exception when others => return; end Module_Symbolic_Traceback; ------------------------------------- -- Multi_Module_Symbolic_Traceback -- ------------------------------------- procedure Multi_Module_Symbolic_Traceback (Traceback : Tracebacks_Array; Suppress_Hex : Boolean; Res : in out Bounded_String) is F : constant Natural := Traceback'First; begin if Traceback'Length = 0 or else Is_Full (Res) then return; end if; if Modules_Cache /= null then -- Search in the cache declare Addr : constant Address := Traceback (F); Hi, Lo, Mid : Natural; begin Lo := Modules_Cache'First; Hi := Modules_Cache'Last; while Lo <= Hi loop Mid := (Lo + Hi) / 2; if Addr < Low_Address (Modules_Cache (Mid).C) then Hi := Mid - 1; elsif Is_Inside (Modules_Cache (Mid).C, Addr) then Multi_Module_Symbolic_Traceback (Traceback, Modules_Cache (Mid).all, Suppress_Hex, Res); return; else Lo := Mid + 1; end if; end loop; -- Not found Hexa_Traceback (Traceback (F .. F), Suppress_Hex, Res); Multi_Module_Symbolic_Traceback (Traceback (F + 1 .. Traceback'Last), Suppress_Hex, Res); end; else -- First try the executable if Is_Inside (Exec_Module.C, Traceback (F)) then Multi_Module_Symbolic_Traceback (Traceback, Exec_Module, Suppress_Hex, Res); return; end if; -- Otherwise, try a shared library declare Load_Addr : aliased System.Address; M_Name : constant String := Module_Name.Get (Addr => Traceback (F), Load_Addr => Load_Addr'Access); Module : Module_Cache; Success : Boolean; begin Init_Module (Module, Success, M_Name, Load_Addr); if Success then Multi_Module_Symbolic_Traceback (Traceback, Module, Suppress_Hex, Res); Close_Module (Module); else -- Module not found Hexa_Traceback (Traceback (F .. F), Suppress_Hex, Res); Multi_Module_Symbolic_Traceback (Traceback (F + 1 .. Traceback'Last), Suppress_Hex, Res); end if; end; end if; end Multi_Module_Symbolic_Traceback; procedure Multi_Module_Symbolic_Traceback (Traceback : Tracebacks_Array; Module : Module_Cache; Suppress_Hex : Boolean; Res : in out Bounded_String) is Pos : Positive; begin -- Will symbolize the first address... Pos := Traceback'First + 1; -- ... and all addresses in the same module Same_Module : loop exit Same_Module when Pos > Traceback'Last; -- Get address to check for corresponding module name exit Same_Module when not Is_Inside (Module.C, Traceback (Pos)); Pos := Pos + 1; end loop Same_Module; Module_Symbolic_Traceback (Traceback (Traceback'First .. Pos - 1), Module, Suppress_Hex, Res); Multi_Module_Symbolic_Traceback (Traceback (Pos .. Traceback'Last), Suppress_Hex, Res); end Multi_Module_Symbolic_Traceback; -------------------- -- Hexa_Traceback -- -------------------- procedure Hexa_Traceback (Traceback : Tracebacks_Array; Suppress_Hex : Boolean; Res : in out Bounded_String) is use System.Traceback_Entries; begin if Suppress_Hex then Append (Res, "..."); Append (Res, ASCII.LF); else for J in Traceback'Range loop Append_Address (Res, PC_For (Traceback (J))); Append (Res, ASCII.LF); end loop; end if; end Hexa_Traceback; -------------------------------- -- Symbolic_Traceback_No_Lock -- -------------------------------- procedure Symbolic_Traceback_No_Lock (Traceback : Tracebacks_Array; Suppress_Hex : Boolean; Res : in out Bounded_String) is begin if Symbolic.Module_Name.Is_Supported then Multi_Module_Symbolic_Traceback (Traceback, Suppress_Hex, Res); else if Exec_Module_State = Failed then Append (Res, "Call stack traceback locations:" & ASCII.LF); Hexa_Traceback (Traceback, Suppress_Hex, Res); else Module_Symbolic_Traceback (Traceback, Exec_Module, Suppress_Hex, Res); end if; end if; end Symbolic_Traceback_No_Lock; ------------------------ -- Symbolic_Traceback -- ------------------------ function Symbolic_Traceback (Traceback : Tracebacks_Array; Suppress_Hex : Boolean) return String is Res : Bounded_String (Max_Length => Max_String_Length); begin System.Soft_Links.Lock_Task.all; Init_Exec_Module; Symbolic_Traceback_No_Lock (Traceback, Suppress_Hex, Res); System.Soft_Links.Unlock_Task.all; return To_String (Res); exception when others => System.Soft_Links.Unlock_Task.all; raise; end Symbolic_Traceback; function Symbolic_Traceback (Traceback : System.Traceback_Entries.Tracebacks_Array) return String is begin return Symbolic_Traceback (Traceback, Suppress_Hex => False); end Symbolic_Traceback; function Symbolic_Traceback_No_Hex (Traceback : System.Traceback_Entries.Tracebacks_Array) return String is begin return Symbolic_Traceback (Traceback, Suppress_Hex => True); end Symbolic_Traceback_No_Hex; function Symbolic_Traceback (E : Ada.Exceptions.Exception_Occurrence; Suppress_Hex : Boolean) return String is begin return Symbolic_Traceback (Ada.Exceptions.Traceback.Tracebacks (E), Suppress_Hex); end Symbolic_Traceback; function Symbolic_Traceback (E : Ada.Exceptions.Exception_Occurrence) return String is begin return Symbolic_Traceback (E, Suppress_Hex => False); end Symbolic_Traceback; function Symbolic_Traceback_No_Hex (E : Ada.Exceptions.Exception_Occurrence) return String is begin return Symbolic_Traceback (E, Suppress_Hex => True); end Symbolic_Traceback_No_Hex; Exception_Tracebacks_Symbolic : Integer; pragma Import (C, Exception_Tracebacks_Symbolic, "__gl_exception_tracebacks_symbolic"); -- Boolean indicating whether symbolic tracebacks should be generated. use Standard_Library; begin -- If this version of this package is available, and the binder switch -Es -- was given, then we want to use this as the decorator by default, and we -- want to turn on tracing for Unhandled_Raise_In_Main. Note that the user -- cannot have already set Exception_Trace, because the runtime library is -- elaborated before user-defined code. if Exception_Tracebacks_Symbolic /= 0 then Exception_Traces.Set_Trace_Decorator (Symbolic_Traceback'Access); pragma Assert (Exception_Trace = RM_Convention); Exception_Trace := Unhandled_Raise_In_Main; end if; end System.Traceback.Symbolic;