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------------------------------------------------------------------------------
--                                                                          --
--                         GNAT COMPILER COMPONENTS                         --
--                                                                          --
--                        S Y S T E M . O S _ L I B                         --
--                                                                          --
--                                 B o d y                                  --
--                                                                          --
--                     Copyright (C) 1995-2009, 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 2,  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.  See the GNU General Public License --
-- for  more details.  You should have  received  a copy of the GNU General --
-- Public License  distributed with GNAT;  see file COPYING.  If not, write --
-- to  the  Free Software Foundation,  51  Franklin  Street,  Fifth  Floor, --
-- Boston, MA 02110-1301, USA.                                              --
--                                                                          --
-- As a special exception,  if other files  instantiate  generics from this --
-- unit, or you link  this unit with other files  to produce an executable, --
-- this  unit  does not  by itself cause  the resulting  executable  to  be --
-- covered  by the  GNU  General  Public  License.  This exception does not --
-- however invalidate  any other reasons why  the executable file  might be --
-- covered by the  GNU Public License.                                      --
--                                                                          --
-- GNAT was originally developed  by the GNAT team at  New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc.      --
--                                                                          --
------------------------------------------------------------------------------
 
pragma Compiler_Unit;
 
with System.Case_Util;
with System.CRTL;
with System.Soft_Links;
with Ada.Unchecked_Conversion;
with Ada.Unchecked_Deallocation;
with System; use System;
 
package body System.OS_Lib is
 
   --  Imported procedures Dup and Dup2 are used in procedures Spawn and
   --  Non_Blocking_Spawn.
 
   function Dup (Fd : File_Descriptor) return File_Descriptor;
   pragma Import (C, Dup, "__gnat_dup");
 
   procedure Dup2 (Old_Fd, New_Fd : File_Descriptor);
   pragma Import (C, Dup2, "__gnat_dup2");
 
   On_Windows : constant Boolean := Directory_Separator = '\';
   --  An indication that we are on Windows. Used in Normalize_Pathname, to
   --  deal with drive letters in the beginning of absolute paths.
 
   package SSL renames System.Soft_Links;
 
   --  The following are used by Create_Temp_File
 
   First_Temp_File_Name : constant String := "GNAT-TEMP-000000.TMP";
   --  Used to initialize Current_Temp_File_Name and Temp_File_Name_Last_Digit
 
   Current_Temp_File_Name : String := First_Temp_File_Name;
   --  Name of the temp file last created
 
   Temp_File_Name_Last_Digit : constant Positive :=
                                 First_Temp_File_Name'Last - 4;
   --  Position of the last digit in Current_Temp_File_Name
 
   Max_Attempts : constant := 100;
   --  The maximum number of attempts to create a new temp file
 
   -----------------------
   -- Local Subprograms --
   -----------------------
 
   function Args_Length (Args : Argument_List) return Natural;
   --  Returns total number of characters needed to create a string of all Args
   --  terminated by ASCII.NUL characters.
 
   procedure Create_Temp_File_Internal
     (FD     : out File_Descriptor;
      Name   : out String_Access;
      Stdout : Boolean);
   --  Internal routine to implement two Create_Temp_File routines. If Stdout
   --  is set to True the created descriptor is stdout-compatible, otherwise
   --  it might not be depending on the OS (VMS is one example). The first two
   --  parameters are as in Create_Temp_File.
 
   function C_String_Length (S : Address) return Integer;
   --  Returns the length of a C string. Does check for null address
   --  (returns 0).
 
   procedure Spawn_Internal
     (Program_Name : String;
      Args         : Argument_List;
      Result       : out Integer;
      Pid          : out Process_Id;
      Blocking     : Boolean);
   --  Internal routine to implement the two Spawn (blocking/non blocking)
   --  routines. If Blocking is set to True then the spawn is blocking
   --  otherwise it is non blocking. In this latter case the Pid contains the
   --  process id number. The first three parameters are as in Spawn. Note that
   --  Spawn_Internal normalizes the argument list before calling the low level
   --  system spawn routines (see Normalize_Arguments).
   --
   --  Note: Normalize_Arguments is designed to do nothing if it is called more
   --  than once, so calling Normalize_Arguments before calling one of the
   --  spawn routines is fine.
 
   function To_Path_String_Access
     (Path_Addr : Address;
      Path_Len  : Integer) return String_Access;
   --  Converts a C String to an Ada String. We could do this making use of
   --  Interfaces.C.Strings but we prefer not to import that entire package
 
   ---------
   -- "<" --
   ---------
 
   function "<"  (X, Y : OS_Time) return Boolean is
   begin
      return Long_Integer (X) < Long_Integer (Y);
   end "<";
 
   ----------
   -- "<=" --
   ----------
 
   function "<="  (X, Y : OS_Time) return Boolean is
   begin
      return Long_Integer (X) <= Long_Integer (Y);
   end "<=";
 
   ---------
   -- ">" --
   ---------
 
   function ">"  (X, Y : OS_Time) return Boolean is
   begin
      return Long_Integer (X) > Long_Integer (Y);
   end ">";
 
   ----------
   -- ">=" --
   ----------
 
   function ">="  (X, Y : OS_Time) return Boolean is
   begin
      return Long_Integer (X) >= Long_Integer (Y);
   end ">=";
 
   -----------------
   -- Args_Length --
   -----------------
 
   function Args_Length (Args : Argument_List) return Natural is
      Len : Natural := 0;
 
   begin
      for J in Args'Range loop
         Len := Len + Args (J)'Length + 1; --  One extra for ASCII.NUL
      end loop;
 
      return Len;
   end Args_Length;
 
   -----------------------------
   -- Argument_String_To_List --
   -----------------------------
 
   function Argument_String_To_List
     (Arg_String : String) return Argument_List_Access
   is
      Max_Args : constant Integer := Arg_String'Length;
      New_Argv : Argument_List (1 .. Max_Args);
      New_Argc : Natural := 0;
      Idx      : Integer;
 
   begin
      Idx := Arg_String'First;
 
      loop
         exit when Idx > Arg_String'Last;
 
         declare
            Quoted  : Boolean := False;
            Backqd  : Boolean := False;
            Old_Idx : Integer;
 
         begin
            Old_Idx := Idx;
 
            loop
               --  An unquoted space is the end of an argument
 
               if not (Backqd or Quoted)
                 and then Arg_String (Idx) = ' '
               then
                  exit;
 
               --  Start of a quoted string
 
               elsif not (Backqd or Quoted)
                 and then Arg_String (Idx) = '"'
               then
                  Quoted := True;
 
               --  End of a quoted string and end of an argument
 
               elsif (Quoted and not Backqd)
                 and then Arg_String (Idx) = '"'
               then
                  Idx := Idx + 1;
                  exit;
 
               --  Following character is backquoted
 
               elsif Arg_String (Idx) = '\' then
                  Backqd := True;
 
               --  Turn off backquoting after advancing one character
 
               elsif Backqd then
                  Backqd := False;
 
               end if;
 
               Idx := Idx + 1;
               exit when Idx > Arg_String'Last;
            end loop;
 
            --  Found an argument
 
            New_Argc := New_Argc + 1;
            New_Argv (New_Argc) :=
              new String'(Arg_String (Old_Idx .. Idx - 1));
 
            --  Skip extraneous spaces
 
            while Idx <= Arg_String'Last and then Arg_String (Idx) = ' ' loop
               Idx := Idx + 1;
            end loop;
         end;
      end loop;
 
      return new Argument_List'(New_Argv (1 .. New_Argc));
   end Argument_String_To_List;
 
   ---------------------
   -- C_String_Length --
   ---------------------
 
   function C_String_Length (S : Address) return Integer is
      function Strlen (S : Address) return Integer;
      pragma Import (C, Strlen, "strlen");
   begin
      if S = Null_Address then
         return 0;
      else
         return Strlen (S);
      end if;
   end C_String_Length;
 
   -----------
   -- Close --
   -----------
 
   procedure Close (FD : File_Descriptor) is
      procedure C_Close (FD : File_Descriptor);
      pragma Import (C, C_Close, "close");
   begin
      C_Close (FD);
   end Close;
 
   procedure Close (FD : File_Descriptor; Status : out Boolean) is
      function C_Close (FD : File_Descriptor) return Integer;
      pragma Import (C, C_Close, "close");
   begin
      Status := (C_Close (FD) = 0);
   end Close;
 
   ---------------
   -- Copy_File --
   ---------------
 
   procedure Copy_File
     (Name     : String;
      Pathname : String;
      Success  : out Boolean;
      Mode     : Copy_Mode := Copy;
      Preserve : Attribute := Time_Stamps)
   is
      From : File_Descriptor;
      To   : File_Descriptor;
 
      Copy_Error : exception;
      --  Internal exception raised to signal error in copy
 
      function Build_Path (Dir : String; File : String) return String;
      --  Returns pathname Dir concatenated with File adding the directory
      --  separator only if needed.
 
      procedure Copy (From, To : File_Descriptor);
      --  Read data from From and place them into To. In both cases the
      --  operations uses the current file position. Raises Constraint_Error
      --  if a problem occurs during the copy.
 
      procedure Copy_To (To_Name : String);
      --  Does a straight copy from source to designated destination file
 
      ----------------
      -- Build_Path --
      ----------------
 
      function Build_Path (Dir : String; File : String) return String is
         Res : String (1 .. Dir'Length + File'Length + 1);
 
         Base_File_Ptr : Integer;
         --  The base file name is File (Base_File_Ptr + 1 .. File'Last)
 
         function Is_Dirsep (C : Character) return Boolean;
         pragma Inline (Is_Dirsep);
         --  Returns True if C is a directory separator. On Windows we
         --  handle both styles of directory separator.
 
         ---------------
         -- Is_Dirsep --
         ---------------
 
         function Is_Dirsep (C : Character) return Boolean is
         begin
            return C = Directory_Separator or else C = '/';
         end Is_Dirsep;
 
      --  Start of processing for Build_Path
 
      begin
         --  Find base file name
 
         Base_File_Ptr := File'Last;
         while Base_File_Ptr >= File'First loop
            exit when Is_Dirsep (File (Base_File_Ptr));
            Base_File_Ptr := Base_File_Ptr - 1;
         end loop;
 
         declare
            Base_File : String renames
                          File (Base_File_Ptr + 1 .. File'Last);
 
         begin
            Res (1 .. Dir'Length) := Dir;
 
            if Is_Dirsep (Dir (Dir'Last)) then
               Res (Dir'Length + 1 .. Dir'Length + Base_File'Length) :=
                 Base_File;
               return Res (1 .. Dir'Length + Base_File'Length);
 
            else
               Res (Dir'Length + 1) := Directory_Separator;
               Res (Dir'Length + 2 .. Dir'Length + 1 + Base_File'Length) :=
                 Base_File;
               return Res (1 .. Dir'Length + 1 + Base_File'Length);
            end if;
         end;
      end Build_Path;
 
      ----------
      -- Copy --
      ----------
 
      procedure Copy (From, To : File_Descriptor) is
         Buf_Size : constant := 200_000;
         type Buf is array (1 .. Buf_Size) of Character;
         type Buf_Ptr is access Buf;
 
         Buffer : Buf_Ptr;
         R      : Integer;
         W      : Integer;
 
         Status_From : Boolean;
         Status_To   : Boolean;
         --  Statuses for the calls to Close
 
         procedure Free is new Ada.Unchecked_Deallocation (Buf, Buf_Ptr);
 
      begin
         --  Check for invalid descriptors, making sure that we do not
         --  accidentally leave an open file descriptor around.
 
         if From = Invalid_FD then
            if To /= Invalid_FD then
               Close (To, Status_To);
            end if;
 
            raise Copy_Error;
 
         elsif To = Invalid_FD then
            Close (From, Status_From);
            raise Copy_Error;
         end if;
 
         --  Allocate the buffer on the heap
 
         Buffer := new Buf;
 
         loop
            R := Read (From, Buffer (1)'Address, Buf_Size);
 
            --  For VMS, the buffer may not be full. So, we need to try again
            --  until there is nothing to read.
 
            exit when R = 0;
 
            W := Write (To, Buffer (1)'Address, R);
 
            if W < R then
 
               --  Problem writing data, could be a disk full. Close files
               --  without worrying about status, since we are raising a
               --  Copy_Error exception in any case.
 
               Close (From, Status_From);
               Close (To, Status_To);
 
               Free (Buffer);
 
               raise Copy_Error;
            end if;
         end loop;
 
         Close (From, Status_From);
         Close (To, Status_To);
 
         Free (Buffer);
 
         if not (Status_From and Status_To) then
            raise Copy_Error;
         end if;
      end Copy;
 
      -------------
      -- Copy_To --
      -------------
 
      procedure Copy_To (To_Name : String) is
 
         function Copy_Attributes
           (From, To : System.Address;
            Mode     : Integer) return Integer;
         pragma Import (C, Copy_Attributes, "__gnat_copy_attribs");
         --  Mode = 0 - copy only time stamps.
         --  Mode = 1 - copy time stamps and read/write/execute attributes
 
         C_From : String (1 .. Name'Length + 1);
         C_To   : String (1 .. To_Name'Length + 1);
 
      begin
         From := Open_Read (Name, Binary);
 
         --  Do not clobber destination file if source file could not be opened
 
         if From /= Invalid_FD then
            To := Create_File (To_Name, Binary);
         end if;
 
         Copy (From, To);
 
         --  Copy attributes
 
         C_From (1 .. Name'Length) := Name;
         C_From (C_From'Last) := ASCII.NUL;
 
         C_To (1 .. To_Name'Length) := To_Name;
         C_To (C_To'Last) := ASCII.NUL;
 
         case Preserve is
 
            when Time_Stamps =>
               if Copy_Attributes (C_From'Address, C_To'Address, 0) = -1 then
                  raise Copy_Error;
               end if;
 
            when Full =>
               if Copy_Attributes (C_From'Address, C_To'Address, 1) = -1 then
                  raise Copy_Error;
               end if;
 
            when None =>
               null;
         end case;
 
      end Copy_To;
 
   --  Start of processing for Copy_File
 
   begin
      Success := True;
 
      --  The source file must exist
 
      if not Is_Regular_File (Name) then
         raise Copy_Error;
      end if;
 
      --  The source file exists
 
      case Mode is
 
         --  Copy case, target file must not exist
 
         when Copy =>
 
            --  If the target file exists, we have an error
 
            if Is_Regular_File (Pathname) then
               raise Copy_Error;
 
            --  Case of target is a directory
 
            elsif Is_Directory (Pathname) then
               declare
                  Dest : constant String := Build_Path (Pathname, Name);
 
               begin
                  --  If target file exists, we have an error, else do copy
 
                  if Is_Regular_File (Dest) then
                     raise Copy_Error;
                  else
                     Copy_To (Dest);
                  end if;
               end;
 
            --  Case of normal copy to file (destination does not exist)
 
            else
               Copy_To (Pathname);
            end if;
 
         --  Overwrite case (destination file may or may not exist)
 
         when Overwrite =>
            if Is_Directory (Pathname) then
               Copy_To (Build_Path (Pathname, Name));
            else
               Copy_To (Pathname);
            end if;
 
         --  Append case (destination file may or may not exist)
 
         when Append =>
 
            --  Appending to existing file
 
            if Is_Regular_File (Pathname) then
 
               --  Append mode and destination file exists, append data at the
               --  end of Pathname. But if we fail to open source file, do not
               --  touch destination file at all.
 
               From := Open_Read (Name, Binary);
               if From /= Invalid_FD then
                  To := Open_Read_Write (Pathname, Binary);
               end if;
 
               Lseek (To, 0, Seek_End);
 
               Copy (From, To);
 
            --  Appending to directory, not allowed
 
            elsif Is_Directory (Pathname) then
               raise Copy_Error;
 
            --  Appending when target file does not exist
 
            else
               Copy_To (Pathname);
            end if;
      end case;
 
   --  All error cases are caught here
 
   exception
      when Copy_Error =>
         Success := False;
   end Copy_File;
 
   procedure Copy_File
     (Name     : C_File_Name;
      Pathname : C_File_Name;
      Success  : out Boolean;
      Mode     : Copy_Mode := Copy;
      Preserve : Attribute := Time_Stamps)
   is
      Ada_Name     : String_Access :=
                       To_Path_String_Access
                         (Name, C_String_Length (Name));
      Ada_Pathname : String_Access :=
                       To_Path_String_Access
                         (Pathname, C_String_Length (Pathname));
   begin
      Copy_File (Ada_Name.all, Ada_Pathname.all, Success, Mode, Preserve);
      Free (Ada_Name);
      Free (Ada_Pathname);
   end Copy_File;
 
   ----------------------
   -- Copy_Time_Stamps --
   ----------------------
 
   procedure Copy_Time_Stamps (Source, Dest : String; Success : out Boolean) is
 
      function Copy_Attributes
        (From, To : System.Address;
         Mode     : Integer) return Integer;
      pragma Import (C, Copy_Attributes, "__gnat_copy_attribs");
      --  Mode = 0 - copy only time stamps.
      --  Mode = 1 - copy time stamps and read/write/execute attributes
 
   begin
      if Is_Regular_File (Source) and then Is_Writable_File (Dest) then
         declare
            C_Source : String (1 .. Source'Length + 1);
            C_Dest   : String (1 .. Dest'Length + 1);
 
         begin
            C_Source (1 .. Source'Length) := Source;
            C_Source (C_Source'Last)      := ASCII.NUL;
 
            C_Dest (1 .. Dest'Length) := Dest;
            C_Dest (C_Dest'Last)      := ASCII.NUL;
 
            if Copy_Attributes (C_Source'Address, C_Dest'Address, 0) = -1 then
               Success := False;
            else
               Success := True;
            end if;
         end;
 
      else
         Success := False;
      end if;
   end Copy_Time_Stamps;
 
   procedure Copy_Time_Stamps
     (Source, Dest : C_File_Name;
      Success      : out Boolean)
   is
      Ada_Source : String_Access :=
                     To_Path_String_Access
                       (Source, C_String_Length (Source));
      Ada_Dest   : String_Access :=
                     To_Path_String_Access
                       (Dest, C_String_Length (Dest));
   begin
      Copy_Time_Stamps (Ada_Source.all, Ada_Dest.all, Success);
      Free (Ada_Source);
      Free (Ada_Dest);
   end Copy_Time_Stamps;
 
   -----------------
   -- Create_File --
   -----------------
 
   function Create_File
     (Name  : C_File_Name;
      Fmode : Mode) return File_Descriptor
   is
      function C_Create_File
        (Name  : C_File_Name;
         Fmode : Mode) return File_Descriptor;
      pragma Import (C, C_Create_File, "__gnat_open_create");
 
   begin
      return C_Create_File (Name, Fmode);
   end Create_File;
 
   function Create_File
     (Name  : String;
      Fmode : Mode) return File_Descriptor
   is
      C_Name : String (1 .. Name'Length + 1);
 
   begin
      C_Name (1 .. Name'Length) := Name;
      C_Name (C_Name'Last)      := ASCII.NUL;
      return Create_File (C_Name (C_Name'First)'Address, Fmode);
   end Create_File;
 
   ---------------------
   -- Create_New_File --
   ---------------------
 
   function Create_New_File
     (Name  : C_File_Name;
      Fmode : Mode) return File_Descriptor
   is
      function C_Create_New_File
        (Name  : C_File_Name;
         Fmode : Mode) return File_Descriptor;
      pragma Import (C, C_Create_New_File, "__gnat_open_new");
 
   begin
      return C_Create_New_File (Name, Fmode);
   end Create_New_File;
 
   function Create_New_File
     (Name  : String;
      Fmode : Mode) return File_Descriptor
   is
      C_Name : String (1 .. Name'Length + 1);
 
   begin
      C_Name (1 .. Name'Length) := Name;
      C_Name (C_Name'Last)      := ASCII.NUL;
      return Create_New_File (C_Name (C_Name'First)'Address, Fmode);
   end Create_New_File;
 
   -----------------------------
   -- Create_Output_Text_File --
   -----------------------------
 
   function Create_Output_Text_File (Name : String) return File_Descriptor is
      function C_Create_File
        (Name : C_File_Name) return File_Descriptor;
      pragma Import (C, C_Create_File, "__gnat_create_output_file");
 
      C_Name : String (1 .. Name'Length + 1);
 
   begin
      C_Name (1 .. Name'Length) := Name;
      C_Name (C_Name'Last)      := ASCII.NUL;
      return C_Create_File (C_Name (C_Name'First)'Address);
   end Create_Output_Text_File;
 
   ----------------------
   -- Create_Temp_File --
   ----------------------
 
   procedure Create_Temp_File
     (FD   : out File_Descriptor;
      Name : out Temp_File_Name)
   is
      function Open_New_Temp
        (Name  : System.Address;
         Fmode : Mode) return File_Descriptor;
      pragma Import (C, Open_New_Temp, "__gnat_open_new_temp");
 
   begin
      FD := Open_New_Temp (Name'Address, Binary);
   end Create_Temp_File;
 
   procedure Create_Temp_File
     (FD   : out File_Descriptor;
      Name : out String_Access)
   is
   begin
      Create_Temp_File_Internal (FD, Name, Stdout => False);
   end Create_Temp_File;
 
   procedure Create_Temp_Output_File
     (FD   : out File_Descriptor;
      Name : out String_Access)
   is
   begin
      Create_Temp_File_Internal (FD, Name, Stdout => True);
   end Create_Temp_Output_File;
 
   -------------------------------
   -- Create_Temp_File_Internal --
   -------------------------------
 
   procedure Create_Temp_File_Internal
     (FD        : out File_Descriptor;
      Name      : out String_Access;
      Stdout    : Boolean)
   is
      Pos      : Positive;
      Attempts : Natural := 0;
      Current  : String (Current_Temp_File_Name'Range);
 
      ---------------------------------
      -- Create_New_Output_Text_File --
      ---------------------------------
 
      function Create_New_Output_Text_File
        (Name : String) return File_Descriptor;
      --  Similar to Create_Output_Text_File, except it fails if the file
      --  already exists. We need this behavior to ensure we don't accidentally
      --  open a temp file that has just been created by a concurrently running
      --  process. There is no point exposing this function, as it's generally
      --  not particularly useful.
 
      function Create_New_Output_Text_File
        (Name : String) return File_Descriptor is
         function C_Create_File
           (Name : C_File_Name) return File_Descriptor;
         pragma Import (C, C_Create_File, "__gnat_create_output_file_new");
 
         C_Name : String (1 .. Name'Length + 1);
 
      begin
         C_Name (1 .. Name'Length) := Name;
         C_Name (C_Name'Last)      := ASCII.NUL;
         return C_Create_File (C_Name (C_Name'First)'Address);
      end Create_New_Output_Text_File;
 
   begin
      --  Loop until a new temp file can be created
 
      File_Loop : loop
         Locked : begin
            --  We need to protect global variable Current_Temp_File_Name
            --  against concurrent access by different tasks.
 
            SSL.Lock_Task.all;
 
            --  Start at the last digit
 
            Pos := Temp_File_Name_Last_Digit;
 
            Digit_Loop :
            loop
               --  Increment the digit by one
 
               case Current_Temp_File_Name (Pos) is
                  when '0' .. '8' =>
                     Current_Temp_File_Name (Pos) :=
                       Character'Succ (Current_Temp_File_Name (Pos));
                     exit Digit_Loop;
 
                  when '9' =>
 
                     --  For 9, set the digit to 0 and go to the previous digit
 
                     Current_Temp_File_Name (Pos) := '0';
                     Pos := Pos - 1;
 
                  when others =>
 
                     --  If it is not a digit, then there are no available
                     --  temp file names. Return Invalid_FD. There is almost
                     --  no chance that this code will be ever be executed,
                     --  since it would mean that there are one million temp
                     --  files in the same directory!
 
                     SSL.Unlock_Task.all;
                     FD := Invalid_FD;
                     Name := null;
                     exit File_Loop;
               end case;
            end loop Digit_Loop;
 
            Current := Current_Temp_File_Name;
 
            --  We can now release the lock, because we are no longer
            --  accessing Current_Temp_File_Name.
 
            SSL.Unlock_Task.all;
 
         exception
            when others =>
               SSL.Unlock_Task.all;
               raise;
         end Locked;
 
         --  Attempt to create the file
 
         if Stdout then
            FD := Create_New_Output_Text_File (Current);
         else
            FD := Create_New_File (Current, Binary);
         end if;
 
         if FD /= Invalid_FD then
            Name := new String'(Current);
            exit File_Loop;
         end if;
 
         if not Is_Regular_File (Current) then
 
            --  If the file does not already exist and we are unable to create
            --  it, we give up after Max_Attempts. Otherwise, we try again with
            --  the next available file name.
 
            Attempts := Attempts + 1;
 
            if Attempts >= Max_Attempts then
               FD := Invalid_FD;
               Name := null;
               exit File_Loop;
            end if;
         end if;
      end loop File_Loop;
   end Create_Temp_File_Internal;
 
   -----------------
   -- Delete_File --
   -----------------
 
   procedure Delete_File (Name : Address; Success : out Boolean) is
      R : Integer;
   begin
      R := System.CRTL.unlink (Name);
      Success := (R = 0);
   end Delete_File;
 
   procedure Delete_File (Name : String; Success : out Boolean) is
      C_Name : String (1 .. Name'Length + 1);
 
   begin
      C_Name (1 .. Name'Length) := Name;
      C_Name (C_Name'Last)      := ASCII.NUL;
 
      Delete_File (C_Name'Address, Success);
   end Delete_File;
 
   ---------------------
   -- File_Time_Stamp --
   ---------------------
 
   function File_Time_Stamp (FD : File_Descriptor) return OS_Time is
      function File_Time (FD : File_Descriptor) return OS_Time;
      pragma Import (C, File_Time, "__gnat_file_time_fd");
   begin
      return File_Time (FD);
   end File_Time_Stamp;
 
   function File_Time_Stamp (Name : C_File_Name) return OS_Time is
      function File_Time (Name : Address) return OS_Time;
      pragma Import (C, File_Time, "__gnat_file_time_name");
   begin
      return File_Time (Name);
   end File_Time_Stamp;
 
   function File_Time_Stamp (Name : String) return OS_Time is
      F_Name : String (1 .. Name'Length + 1);
   begin
      F_Name (1 .. Name'Length) := Name;
      F_Name (F_Name'Last)      := ASCII.NUL;
      return File_Time_Stamp (F_Name'Address);
   end File_Time_Stamp;
 
   ---------------------------
   -- Get_Debuggable_Suffix --
   ---------------------------
 
   function Get_Debuggable_Suffix return String_Access is
      procedure Get_Suffix_Ptr (Length, Ptr : Address);
      pragma Import (C, Get_Suffix_Ptr, "__gnat_get_debuggable_suffix_ptr");
 
      procedure Strncpy (Astring_Addr, Cstring : Address; N : Integer);
      pragma Import (C, Strncpy, "strncpy");
 
      Suffix_Ptr    : Address;
      Suffix_Length : Integer;
      Result        : String_Access;
 
   begin
      Get_Suffix_Ptr (Suffix_Length'Address, Suffix_Ptr'Address);
 
      Result := new String (1 .. Suffix_Length);
 
      if Suffix_Length > 0 then
         Strncpy (Result.all'Address, Suffix_Ptr, Suffix_Length);
      end if;
 
      return Result;
   end Get_Debuggable_Suffix;
 
   ---------------------------
   -- Get_Executable_Suffix --
   ---------------------------
 
   function Get_Executable_Suffix return String_Access is
      procedure Get_Suffix_Ptr (Length, Ptr : Address);
      pragma Import (C, Get_Suffix_Ptr, "__gnat_get_executable_suffix_ptr");
 
      procedure Strncpy (Astring_Addr, Cstring : Address; N : Integer);
      pragma Import (C, Strncpy, "strncpy");
 
      Suffix_Ptr    : Address;
      Suffix_Length : Integer;
      Result        : String_Access;
 
   begin
      Get_Suffix_Ptr (Suffix_Length'Address, Suffix_Ptr'Address);
 
      Result := new String (1 .. Suffix_Length);
 
      if Suffix_Length > 0 then
         Strncpy (Result.all'Address, Suffix_Ptr, Suffix_Length);
      end if;
 
      return Result;
   end Get_Executable_Suffix;
 
   -----------------------
   -- Get_Object_Suffix --
   -----------------------
 
   function Get_Object_Suffix return String_Access is
      procedure Get_Suffix_Ptr (Length, Ptr : Address);
      pragma Import (C, Get_Suffix_Ptr, "__gnat_get_object_suffix_ptr");
 
      procedure Strncpy (Astring_Addr, Cstring : Address; N : Integer);
      pragma Import (C, Strncpy, "strncpy");
 
      Suffix_Ptr    : Address;
      Suffix_Length : Integer;
      Result        : String_Access;
 
   begin
      Get_Suffix_Ptr (Suffix_Length'Address, Suffix_Ptr'Address);
 
      Result := new String (1 .. Suffix_Length);
 
      if Suffix_Length > 0 then
         Strncpy (Result.all'Address, Suffix_Ptr, Suffix_Length);
      end if;
 
      return Result;
   end Get_Object_Suffix;
 
   ----------------------------------
   -- Get_Target_Debuggable_Suffix --
   ----------------------------------
 
   function Get_Target_Debuggable_Suffix return String_Access is
      Target_Exec_Ext_Ptr : Address;
      pragma Import
        (C, Target_Exec_Ext_Ptr, "__gnat_target_debuggable_extension");
 
      procedure Strncpy (Astring_Addr, Cstring : Address; N : Integer);
      pragma Import (C, Strncpy, "strncpy");
 
      function Strlen (Cstring : Address) return Integer;
      pragma Import (C, Strlen, "strlen");
 
      Suffix_Length : Integer;
      Result        : String_Access;
 
   begin
      Suffix_Length := Strlen (Target_Exec_Ext_Ptr);
 
      Result := new String (1 .. Suffix_Length);
 
      if Suffix_Length > 0 then
         Strncpy (Result.all'Address, Target_Exec_Ext_Ptr, Suffix_Length);
      end if;
 
      return Result;
   end Get_Target_Debuggable_Suffix;
 
   ----------------------------------
   -- Get_Target_Executable_Suffix --
   ----------------------------------
 
   function Get_Target_Executable_Suffix return String_Access is
      Target_Exec_Ext_Ptr : Address;
      pragma Import
        (C, Target_Exec_Ext_Ptr, "__gnat_target_executable_extension");
 
      procedure Strncpy (Astring_Addr, Cstring : Address; N : Integer);
      pragma Import (C, Strncpy, "strncpy");
 
      function Strlen (Cstring : Address) return Integer;
      pragma Import (C, Strlen, "strlen");
 
      Suffix_Length : Integer;
      Result        : String_Access;
 
   begin
      Suffix_Length := Strlen (Target_Exec_Ext_Ptr);
 
      Result := new String (1 .. Suffix_Length);
 
      if Suffix_Length > 0 then
         Strncpy (Result.all'Address, Target_Exec_Ext_Ptr, Suffix_Length);
      end if;
 
      return Result;
   end Get_Target_Executable_Suffix;
 
   ------------------------------
   -- Get_Target_Object_Suffix --
   ------------------------------
 
   function Get_Target_Object_Suffix return String_Access is
      Target_Object_Ext_Ptr : Address;
      pragma Import
        (C, Target_Object_Ext_Ptr, "__gnat_target_object_extension");
 
      procedure Strncpy (Astring_Addr, Cstring : Address; N : Integer);
      pragma Import (C, Strncpy, "strncpy");
 
      function Strlen (Cstring : Address) return Integer;
      pragma Import (C, Strlen, "strlen");
 
      Suffix_Length : Integer;
      Result        : String_Access;
 
   begin
      Suffix_Length := Strlen (Target_Object_Ext_Ptr);
 
      Result := new String (1 .. Suffix_Length);
 
      if Suffix_Length > 0 then
         Strncpy (Result.all'Address, Target_Object_Ext_Ptr, Suffix_Length);
      end if;
 
      return Result;
   end Get_Target_Object_Suffix;
 
   ------------
   -- Getenv --
   ------------
 
   function Getenv (Name : String) return String_Access is
      procedure Get_Env_Value_Ptr (Name, Length, Ptr : Address);
      pragma Import (C, Get_Env_Value_Ptr, "__gnat_getenv");
 
      procedure Strncpy (Astring_Addr, Cstring : Address; N : Integer);
      pragma Import (C, Strncpy, "strncpy");
 
      Env_Value_Ptr    : aliased Address;
      Env_Value_Length : aliased Integer;
      F_Name           : aliased String (1 .. Name'Length + 1);
      Result           : String_Access;
 
   begin
      F_Name (1 .. Name'Length) := Name;
      F_Name (F_Name'Last)      := ASCII.NUL;
 
      Get_Env_Value_Ptr
        (F_Name'Address, Env_Value_Length'Address, Env_Value_Ptr'Address);
 
      Result := new String (1 .. Env_Value_Length);
 
      if Env_Value_Length > 0 then
         Strncpy (Result.all'Address, Env_Value_Ptr, Env_Value_Length);
      end if;
 
      return Result;
   end Getenv;
 
   ------------
   -- GM_Day --
   ------------
 
   function GM_Day (Date : OS_Time) return Day_Type is
      D  : Day_Type;
 
      pragma Warnings (Off);
      Y  : Year_Type;
      Mo : Month_Type;
      H  : Hour_Type;
      Mn : Minute_Type;
      S  : Second_Type;
      pragma Warnings (On);
 
   begin
      GM_Split (Date, Y, Mo, D, H, Mn, S);
      return D;
   end GM_Day;
 
   -------------
   -- GM_Hour --
   -------------
 
   function GM_Hour (Date : OS_Time) return Hour_Type is
      H  : Hour_Type;
 
      pragma Warnings (Off);
      Y  : Year_Type;
      Mo : Month_Type;
      D  : Day_Type;
      Mn : Minute_Type;
      S  : Second_Type;
      pragma Warnings (On);
 
   begin
      GM_Split (Date, Y, Mo, D, H, Mn, S);
      return H;
   end GM_Hour;
 
   ---------------
   -- GM_Minute --
   ---------------
 
   function GM_Minute (Date : OS_Time) return Minute_Type is
      Mn : Minute_Type;
 
      pragma Warnings (Off);
      Y  : Year_Type;
      Mo : Month_Type;
      D  : Day_Type;
      H  : Hour_Type;
      S  : Second_Type;
      pragma Warnings (On);
 
   begin
      GM_Split (Date, Y, Mo, D, H, Mn, S);
      return Mn;
   end GM_Minute;
 
   --------------
   -- GM_Month --
   --------------
 
   function GM_Month (Date : OS_Time) return Month_Type is
      Mo : Month_Type;
 
      pragma Warnings (Off);
      Y  : Year_Type;
      D  : Day_Type;
      H  : Hour_Type;
      Mn : Minute_Type;
      S  : Second_Type;
      pragma Warnings (On);
 
   begin
      GM_Split (Date, Y, Mo, D, H, Mn, S);
      return Mo;
   end GM_Month;
 
   ---------------
   -- GM_Second --
   ---------------
 
   function GM_Second (Date : OS_Time) return Second_Type is
      S  : Second_Type;
 
      pragma Warnings (Off);
      Y  : Year_Type;
      Mo : Month_Type;
      D  : Day_Type;
      H  : Hour_Type;
      Mn : Minute_Type;
      pragma Warnings (On);
 
   begin
      GM_Split (Date, Y, Mo, D, H, Mn, S);
      return S;
   end GM_Second;
 
   --------------
   -- GM_Split --
   --------------
 
   procedure GM_Split
     (Date   : OS_Time;
      Year   : out Year_Type;
      Month  : out Month_Type;
      Day    : out Day_Type;
      Hour   : out Hour_Type;
      Minute : out Minute_Type;
      Second : out Second_Type)
   is
      procedure To_GM_Time
        (P_Time_T, P_Year, P_Month, P_Day, P_Hours, P_Mins, P_Secs : Address);
      pragma Import (C, To_GM_Time, "__gnat_to_gm_time");
 
      T  : OS_Time := Date;
      Y  : Integer;
      Mo : Integer;
      D  : Integer;
      H  : Integer;
      Mn : Integer;
      S  : Integer;
 
   begin
      --  Use the global lock because To_GM_Time is not thread safe
 
      Locked_Processing : begin
         SSL.Lock_Task.all;
         To_GM_Time
           (T'Address, Y'Address, Mo'Address, D'Address,
            H'Address, Mn'Address, S'Address);
         SSL.Unlock_Task.all;
 
      exception
         when others =>
            SSL.Unlock_Task.all;
            raise;
      end Locked_Processing;
 
      Year   := Y + 1900;
      Month  := Mo + 1;
      Day    := D;
      Hour   := H;
      Minute := Mn;
      Second := S;
   end GM_Split;
 
   -------------
   -- GM_Year --
   -------------
 
   function GM_Year (Date : OS_Time) return Year_Type is
      Y  : Year_Type;
 
      pragma Warnings (Off);
      Mo : Month_Type;
      D  : Day_Type;
      H  : Hour_Type;
      Mn : Minute_Type;
      S  : Second_Type;
      pragma Warnings (On);
 
   begin
      GM_Split (Date, Y, Mo, D, H, Mn, S);
      return Y;
   end GM_Year;
 
   ----------------------
   -- Is_Absolute_Path --
   ----------------------
 
   function Is_Absolute_Path (Name : String) return Boolean is
      function Is_Absolute_Path
        (Name   : Address;
         Length : Integer) return Integer;
      pragma Import (C, Is_Absolute_Path, "__gnat_is_absolute_path");
   begin
      return Is_Absolute_Path (Name'Address, Name'Length) /= 0;
   end Is_Absolute_Path;
 
   ------------------
   -- Is_Directory --
   ------------------
 
   function Is_Directory (Name : C_File_Name) return Boolean is
      function Is_Directory (Name : Address) return Integer;
      pragma Import (C, Is_Directory, "__gnat_is_directory");
   begin
      return Is_Directory (Name) /= 0;
   end Is_Directory;
 
   function Is_Directory (Name : String) return Boolean is
      F_Name : String (1 .. Name'Length + 1);
   begin
      F_Name (1 .. Name'Length) := Name;
      F_Name (F_Name'Last)      := ASCII.NUL;
      return Is_Directory (F_Name'Address);
   end Is_Directory;
 
   ----------------------
   -- Is_Readable_File --
   ----------------------
 
   function Is_Readable_File (Name : C_File_Name) return Boolean is
      function Is_Readable_File (Name : Address) return Integer;
      pragma Import (C, Is_Readable_File, "__gnat_is_readable_file");
   begin
      return Is_Readable_File (Name) /= 0;
   end Is_Readable_File;
 
   function Is_Readable_File (Name : String) return Boolean is
      F_Name : String (1 .. Name'Length + 1);
   begin
      F_Name (1 .. Name'Length) := Name;
      F_Name (F_Name'Last)      := ASCII.NUL;
      return Is_Readable_File (F_Name'Address);
   end Is_Readable_File;
 
   ------------------------
   -- Is_Executable_File --
   ------------------------
 
   function Is_Executable_File (Name : C_File_Name) return Boolean is
      function Is_Executable_File (Name : Address) return Integer;
      pragma Import (C, Is_Executable_File, "__gnat_is_executable_file");
   begin
      return Is_Executable_File (Name) /= 0;
   end Is_Executable_File;
 
   function Is_Executable_File (Name : String) return Boolean is
      F_Name : String (1 .. Name'Length + 1);
   begin
      F_Name (1 .. Name'Length) := Name;
      F_Name (F_Name'Last)      := ASCII.NUL;
      return Is_Executable_File (F_Name'Address);
   end Is_Executable_File;
 
   ---------------------
   -- Is_Regular_File --
   ---------------------
 
   function Is_Regular_File (Name : C_File_Name) return Boolean is
      function Is_Regular_File (Name : Address) return Integer;
      pragma Import (C, Is_Regular_File, "__gnat_is_regular_file");
   begin
      return Is_Regular_File (Name) /= 0;
   end Is_Regular_File;
 
   function Is_Regular_File (Name : String) return Boolean is
      F_Name : String (1 .. Name'Length + 1);
   begin
      F_Name (1 .. Name'Length) := Name;
      F_Name (F_Name'Last)      := ASCII.NUL;
      return Is_Regular_File (F_Name'Address);
   end Is_Regular_File;
 
   ----------------------
   -- Is_Symbolic_Link --
   ----------------------
 
   function Is_Symbolic_Link (Name : C_File_Name) return Boolean is
      function Is_Symbolic_Link (Name : Address) return Integer;
      pragma Import (C, Is_Symbolic_Link, "__gnat_is_symbolic_link");
   begin
      return Is_Symbolic_Link (Name) /= 0;
   end Is_Symbolic_Link;
 
   function Is_Symbolic_Link (Name : String) return Boolean is
      F_Name : String (1 .. Name'Length + 1);
   begin
      F_Name (1 .. Name'Length) := Name;
      F_Name (F_Name'Last)      := ASCII.NUL;
      return Is_Symbolic_Link (F_Name'Address);
   end Is_Symbolic_Link;
 
   ----------------------
   -- Is_Writable_File --
   ----------------------
 
   function Is_Writable_File (Name : C_File_Name) return Boolean is
      function Is_Writable_File (Name : Address) return Integer;
      pragma Import (C, Is_Writable_File, "__gnat_is_writable_file");
   begin
      return Is_Writable_File (Name) /= 0;
   end Is_Writable_File;
 
   function Is_Writable_File (Name : String) return Boolean is
      F_Name : String (1 .. Name'Length + 1);
   begin
      F_Name (1 .. Name'Length) := Name;
      F_Name (F_Name'Last)      := ASCII.NUL;
      return Is_Writable_File (F_Name'Address);
   end Is_Writable_File;
 
   -------------------------
   -- Locate_Exec_On_Path --
   -------------------------
 
   function Locate_Exec_On_Path
     (Exec_Name : String) return String_Access
   is
      function Locate_Exec_On_Path (C_Exec_Name : Address) return Address;
      pragma Import (C, Locate_Exec_On_Path, "__gnat_locate_exec_on_path");
 
      procedure Free (Ptr : System.Address);
      pragma Import (C, Free, "free");
 
      C_Exec_Name  : String (1 .. Exec_Name'Length + 1);
      Path_Addr    : Address;
      Path_Len     : Integer;
      Result       : String_Access;
 
   begin
      C_Exec_Name (1 .. Exec_Name'Length)   := Exec_Name;
      C_Exec_Name (C_Exec_Name'Last)        := ASCII.NUL;
 
      Path_Addr := Locate_Exec_On_Path (C_Exec_Name'Address);
      Path_Len  := C_String_Length (Path_Addr);
 
      if Path_Len = 0 then
         return null;
 
      else
         Result := To_Path_String_Access (Path_Addr, Path_Len);
         Free (Path_Addr);
 
         --  Always return an absolute path name
 
         if not Is_Absolute_Path (Result.all) then
            declare
               Absolute_Path : constant String :=
                                 Normalize_Pathname (Result.all);
            begin
               Free (Result);
               Result := new String'(Absolute_Path);
            end;
         end if;
 
         return Result;
      end if;
   end Locate_Exec_On_Path;
 
   -------------------------
   -- Locate_Regular_File --
   -------------------------
 
   function Locate_Regular_File
     (File_Name : C_File_Name;
      Path      : C_File_Name) return String_Access
   is
      function Locate_Regular_File
        (C_File_Name, Path_Val : Address) return Address;
      pragma Import (C, Locate_Regular_File, "__gnat_locate_regular_file");
 
      procedure Free (Ptr : System.Address);
      pragma Import (C, Free, "free");
 
      Path_Addr    : Address;
      Path_Len     : Integer;
      Result       : String_Access;
 
   begin
      Path_Addr := Locate_Regular_File (File_Name, Path);
      Path_Len  := C_String_Length (Path_Addr);
 
      if Path_Len = 0 then
         return null;
 
      else
         Result := To_Path_String_Access (Path_Addr, Path_Len);
         Free (Path_Addr);
         return Result;
      end if;
   end Locate_Regular_File;
 
   function Locate_Regular_File
     (File_Name : String;
      Path      : String) return String_Access
   is
      C_File_Name : String (1 .. File_Name'Length + 1);
      C_Path      : String (1 .. Path'Length + 1);
      Result      : String_Access;
 
   begin
      C_File_Name (1 .. File_Name'Length)   := File_Name;
      C_File_Name (C_File_Name'Last)        := ASCII.NUL;
 
      C_Path    (1 .. Path'Length)          := Path;
      C_Path    (C_Path'Last)               := ASCII.NUL;
 
      Result := Locate_Regular_File (C_File_Name'Address, C_Path'Address);
 
      --  Always return an absolute path name
 
      if Result /= null and then not Is_Absolute_Path (Result.all) then
         declare
            Absolute_Path : constant String := Normalize_Pathname (Result.all);
         begin
            Free (Result);
            Result := new String'(Absolute_Path);
         end;
      end if;
 
      return Result;
   end Locate_Regular_File;
 
   ------------------------
   -- Non_Blocking_Spawn --
   ------------------------
 
   function Non_Blocking_Spawn
     (Program_Name : String;
      Args         : Argument_List) return Process_Id
   is
      Pid  : Process_Id;
      Junk : Integer;
      pragma Warnings (Off, Junk);
   begin
      Spawn_Internal (Program_Name, Args, Junk, Pid, Blocking => False);
      return Pid;
   end Non_Blocking_Spawn;
 
   function Non_Blocking_Spawn
     (Program_Name           : String;
      Args                   : Argument_List;
      Output_File_Descriptor : File_Descriptor;
      Err_To_Out             : Boolean := True) return Process_Id
   is
      Saved_Output : File_Descriptor;
      Saved_Error  : File_Descriptor := Invalid_FD; -- prevent warning
      Pid          : Process_Id;
 
   begin
      if Output_File_Descriptor = Invalid_FD then
         return Invalid_Pid;
      end if;
 
      --  Set standard output and, if specified, error to the temporary file
 
      Saved_Output := Dup (Standout);
      Dup2 (Output_File_Descriptor, Standout);
 
      if Err_To_Out then
         Saved_Error  := Dup (Standerr);
         Dup2 (Output_File_Descriptor, Standerr);
      end if;
 
      --  Spawn the program
 
      Pid := Non_Blocking_Spawn (Program_Name, Args);
 
      --  Restore the standard output and error
 
      Dup2 (Saved_Output, Standout);
 
      if Err_To_Out then
         Dup2 (Saved_Error, Standerr);
      end if;
 
      --  And close the saved standard output and error file descriptors
 
      Close (Saved_Output);
 
      if Err_To_Out then
         Close (Saved_Error);
      end if;
 
      return Pid;
   end Non_Blocking_Spawn;
 
   function Non_Blocking_Spawn
     (Program_Name : String;
      Args         : Argument_List;
      Output_File  : String;
      Err_To_Out   : Boolean := True) return Process_Id
   is
      Output_File_Descriptor : constant File_Descriptor :=
                                 Create_Output_Text_File (Output_File);
      Result : Process_Id;
 
   begin
      --  Do not attempt to spawn if the output file could not be created
 
      if Output_File_Descriptor = Invalid_FD then
         return Invalid_Pid;
 
      else
         Result := Non_Blocking_Spawn
                     (Program_Name, Args, Output_File_Descriptor, Err_To_Out);
 
         --  Close the file just created for the output, as the file descriptor
         --  cannot be used anywhere, being a local value. It is safe to do
         --  that, as the file descriptor has been duplicated to form
         --  standard output and error of the spawned process.
 
         Close (Output_File_Descriptor);
 
         return Result;
      end if;
   end Non_Blocking_Spawn;
 
   -------------------------
   -- Normalize_Arguments --
   -------------------------
 
   procedure Normalize_Arguments (Args : in out Argument_List) is
 
      procedure Quote_Argument (Arg : in out String_Access);
      --  Add quote around argument if it contains spaces
 
      C_Argument_Needs_Quote : Integer;
      pragma Import (C, C_Argument_Needs_Quote, "__gnat_argument_needs_quote");
      Argument_Needs_Quote : constant Boolean := C_Argument_Needs_Quote /= 0;
 
      --------------------
      -- Quote_Argument --
      --------------------
 
      procedure Quote_Argument (Arg : in out String_Access) is
         Res          : String (1 .. Arg'Length * 2);
         J            : Positive := 1;
         Quote_Needed : Boolean  := False;
 
      begin
         if Arg (Arg'First) /= '"' or else Arg (Arg'Last) /= '"' then
 
            --  Starting quote
 
            Res (J) := '"';
 
            for K in Arg'Range loop
 
               J := J + 1;
 
               if Arg (K) = '"' then
                  Res (J) := '\';
                  J := J + 1;
                  Res (J) := '"';
                  Quote_Needed := True;
 
               elsif Arg (K) = ' ' then
                  Res (J) := Arg (K);
                  Quote_Needed := True;
 
               else
                  Res (J) := Arg (K);
               end if;
 
            end loop;
 
            if Quote_Needed then
 
               --  If null terminated string, put the quote before
 
               if Res (J) = ASCII.NUL then
                  Res (J) := '"';
                  J := J + 1;
                  Res (J) := ASCII.NUL;
 
               --  If argument is terminated by '\', then double it. Otherwise
               --  the ending quote will be taken as-is. This is quite strange
               --  spawn behavior from Windows, but this is what we see!
 
               else
                  if Res (J) = '\' then
                     J := J + 1;
                     Res (J) := '\';
                  end if;
 
                  --  Ending quote
 
                  J := J + 1;
                  Res (J) := '"';
               end if;
 
               declare
                  Old : String_Access := Arg;
 
               begin
                  Arg := new String'(Res (1 .. J));
                  Free (Old);
               end;
            end if;
 
         end if;
      end Quote_Argument;
 
   --  Start of processing for Normalize_Arguments
 
   begin
      if Argument_Needs_Quote then
         for K in Args'Range loop
            if Args (K) /= null and then Args (K)'Length /= 0 then
               Quote_Argument (Args (K));
            end if;
         end loop;
      end if;
   end Normalize_Arguments;
 
   ------------------------
   -- Normalize_Pathname --
   ------------------------
 
   function Normalize_Pathname
     (Name           : String;
      Directory      : String  := "";
      Resolve_Links  : Boolean := True;
      Case_Sensitive : Boolean := True) return String
   is
      Max_Path : Integer;
      pragma Import (C, Max_Path, "__gnat_max_path_len");
      --  Maximum length of a path name
 
      procedure Get_Current_Dir
        (Dir    : System.Address;
         Length : System.Address);
      pragma Import (C, Get_Current_Dir, "__gnat_get_current_dir");
 
      Path_Buffer : String (1 .. Max_Path + Max_Path + 2);
      End_Path    : Natural := 0;
      Link_Buffer : String (1 .. Max_Path + 2);
      Status      : Integer;
      Last        : Positive;
      Start       : Natural;
      Finish      : Positive;
 
      Max_Iterations : constant := 500;
 
      function Get_File_Names_Case_Sensitive return Integer;
      pragma Import
        (C, Get_File_Names_Case_Sensitive,
         "__gnat_get_file_names_case_sensitive");
 
      Fold_To_Lower_Case : constant Boolean :=
                             not Case_Sensitive
                               and then Get_File_Names_Case_Sensitive = 0;
 
      function Readlink
        (Path   : System.Address;
         Buf    : System.Address;
         Bufsiz : Integer) return Integer;
      pragma Import (C, Readlink, "__gnat_readlink");
 
      function To_Canonical_File_Spec
        (Host_File : System.Address) return System.Address;
      pragma Import
        (C, To_Canonical_File_Spec, "__gnat_to_canonical_file_spec");
 
      The_Name : String (1 .. Name'Length + 1);
      Canonical_File_Addr : System.Address;
      Canonical_File_Len  : Integer;
 
      function Strlen (S : System.Address) return Integer;
      pragma Import (C, Strlen, "strlen");
 
      function Final_Value (S : String) return String;
      --  Make final adjustment to the returned string. This function strips
      --  trailing directory separators, and folds returned string to lower
      --  case if required.
 
      function Get_Directory  (Dir : String) return String;
      --  If Dir is not empty, return it, adding a directory separator
      --  if not already present, otherwise return current working directory
      --  with terminating directory separator.
 
      -----------------
      -- Final_Value --
      -----------------
 
      function Final_Value (S : String) return String is
         S1 : String := S;
         --  We may need to fold S to lower case, so we need a variable
 
         Last : Natural;
 
      begin
         if Fold_To_Lower_Case then
            System.Case_Util.To_Lower (S1);
         end if;
 
         --  Remove trailing directory separator, if any
 
         Last := S1'Last;
 
         if Last > 1
           and then (S1 (Last) = '/'
                       or else
                     S1 (Last) = Directory_Separator)
         then
            --  Special case for Windows: C:\
 
            if Last = 3
              and then S1 (1) /= Directory_Separator
              and then S1 (2) = ':'
            then
               null;
 
            else
               Last := Last - 1;
            end if;
         end if;
 
         return S1 (1 .. Last);
      end Final_Value;
 
      -------------------
      -- Get_Directory --
      -------------------
 
      function Get_Directory (Dir : String) return String is
         Result : String (1 .. Dir'Length + 1);
         Length : constant Natural := Dir'Length;
 
      begin
         --  Directory given, add directory separator if needed
 
         if Length > 0 then
            Result (1 .. Length) := Dir;
 
            --  On Windows, change all '/' to '\'
 
            if On_Windows then
               for J in 1 .. Length loop
                  if Result (J) = '/' then
                     Result (J) := Directory_Separator;
                  end if;
               end loop;
            end if;
 
            --  Add directory separator, if needed
 
            if Result (Length) = Directory_Separator then
               return Result (1 .. Length);
            else
               Result (Result'Length) := Directory_Separator;
               return Result;
            end if;
 
         --  Directory name not given, get current directory
 
         else
            declare
               Buffer   : String (1 .. Max_Path + 2);
               Path_Len : Natural := Max_Path;
 
            begin
               Get_Current_Dir (Buffer'Address, Path_Len'Address);
 
               if Buffer (Path_Len) /= Directory_Separator then
                  Path_Len := Path_Len + 1;
                  Buffer (Path_Len) := Directory_Separator;
               end if;
 
               --  By default, the drive letter on Windows is in upper case
 
               if On_Windows
                 and then Path_Len >= 2
                 and then Buffer (2) = ':'
               then
                  System.Case_Util.To_Upper (Buffer (1 .. 1));
               end if;
 
               return Buffer (1 .. Path_Len);
            end;
         end if;
      end Get_Directory;
 
   --  Start of processing for Normalize_Pathname
 
   begin
      --  Special case, if name is null, then return null
 
      if Name'Length = 0 then
         return "";
      end if;
 
      --  First, convert VMS file spec to Unix file spec.
      --  If Name is not in VMS syntax, then this is equivalent
      --  to put Name at the beginning of Path_Buffer.
 
      VMS_Conversion : begin
         The_Name (1 .. Name'Length) := Name;
         The_Name (The_Name'Last) := ASCII.NUL;
 
         Canonical_File_Addr := To_Canonical_File_Spec (The_Name'Address);
         Canonical_File_Len  := Strlen (Canonical_File_Addr);
 
         --  If VMS syntax conversion has failed, return an empty string
         --  to indicate the failure.
 
         if Canonical_File_Len = 0 then
            return "";
         end if;
 
         declare
            subtype Path_String is String (1 .. Canonical_File_Len);
            type    Path_String_Access is access Path_String;
 
            function Address_To_Access is new
               Ada.Unchecked_Conversion (Source => Address,
                                     Target => Path_String_Access);
 
            Path_Access : constant Path_String_Access :=
                            Address_To_Access (Canonical_File_Addr);
 
         begin
            Path_Buffer (1 .. Canonical_File_Len) := Path_Access.all;
            End_Path := Canonical_File_Len;
            Last := 1;
         end;
      end VMS_Conversion;
 
      --  Replace all '/' by Directory Separators (this is for Windows)
 
      if Directory_Separator /= '/' then
         for Index in 1 .. End_Path loop
            if Path_Buffer (Index) = '/' then
               Path_Buffer (Index) := Directory_Separator;
            end if;
         end loop;
      end if;
 
      --  Resolve directory names for Windows (formerly also VMS)
 
      --  On VMS, if we have a Unix path such as /temp/..., and TEMP is a
      --  logical name, we must not try to resolve this logical name, because
      --  it may have multiple equivalences and if resolved we will only
      --  get the first one.
 
      if On_Windows then
 
         --  On Windows, if we have an absolute path starting with a directory
         --  separator, we need to have the drive letter appended in front.
 
         --  On Windows, Get_Current_Dir will return a suitable directory name
         --  (path starting with a drive letter on Windows). So we take this
         --  drive letter and prepend it to the current path.
 
         if Path_Buffer (1) = Directory_Separator
           and then Path_Buffer (2) /= Directory_Separator
         then
            declare
               Cur_Dir : constant String := Get_Directory ("");
               --  Get the current directory to get the drive letter
 
            begin
               if Cur_Dir'Length > 2
                 and then Cur_Dir (Cur_Dir'First + 1) = ':'
               then
                  Path_Buffer (3 .. End_Path + 2) :=
                    Path_Buffer (1 .. End_Path);
                  Path_Buffer (1 .. 2) :=
                    Cur_Dir (Cur_Dir'First .. Cur_Dir'First + 1);
                  End_Path := End_Path + 2;
               end if;
            end;
 
         --  We have a drive letter, ensure it is upper-case
 
         elsif Path_Buffer (1) in 'a' .. 'z'
           and then Path_Buffer (2) = ':'
         then
            System.Case_Util.To_Upper (Path_Buffer (1 .. 1));
         end if;
      end if;
 
      --  On Windows, remove all double-quotes that are possibly part of the
      --  path but can cause problems with other methods.
 
      if On_Windows then
         declare
            Index : Natural;
 
         begin
            Index := Path_Buffer'First;
            for Current in Path_Buffer'First .. End_Path loop
               if Path_Buffer (Current) /= '"' then
                  Path_Buffer (Index) := Path_Buffer (Current);
                  Index := Index + 1;
               end if;
            end loop;
 
            End_Path := Index - 1;
         end;
      end if;
 
      --  Start the conversions
 
      --  If this is not finished after Max_Iterations, give up and return an
      --  empty string.
 
      for J in 1 .. Max_Iterations loop
 
         --  If we don't have an absolute pathname, prepend the directory
         --  Reference_Dir.
 
         if Last = 1
           and then not Is_Absolute_Path (Path_Buffer (1 .. End_Path))
         then
            declare
               Reference_Dir : constant String  := Get_Directory (Directory);
               Ref_Dir_Len   : constant Natural := Reference_Dir'Length;
               --  Current directory name specified and its length
 
            begin
               Path_Buffer (Ref_Dir_Len + 1 .. Ref_Dir_Len + End_Path) :=
                 Path_Buffer (1 .. End_Path);
               End_Path := Ref_Dir_Len + End_Path;
               Path_Buffer (1 .. Ref_Dir_Len) := Reference_Dir;
               Last := Ref_Dir_Len;
            end;
         end if;
 
         Start  := Last + 1;
         Finish := Last;
 
         --  Ensure that Windows network drives are kept, e.g: \\server\drive-c
 
         if Start = 2
           and then Directory_Separator = '\'
           and then Path_Buffer (1 .. 2) = "\\"
         then
            Start := 3;
         end if;
 
         --  If we have traversed the full pathname, return it
 
         if Start > End_Path then
            return Final_Value (Path_Buffer (1 .. End_Path));
         end if;
 
         --  Remove duplicate directory separators
 
         while Path_Buffer (Start) = Directory_Separator loop
            if Start = End_Path then
               return Final_Value (Path_Buffer (1 .. End_Path - 1));
 
            else
               Path_Buffer (Start .. End_Path - 1) :=
                 Path_Buffer (Start + 1 .. End_Path);
               End_Path := End_Path - 1;
            end if;
         end loop;
 
         --  Find the end of the current field: last character or the one
         --  preceding the next directory separator.
 
         while Finish < End_Path
           and then Path_Buffer (Finish + 1) /= Directory_Separator
         loop
            Finish := Finish + 1;
         end loop;
 
         --  Remove "." field
 
         if Start = Finish and then Path_Buffer (Start) = '.' then
            if Start = End_Path then
               if Last = 1 then
                  return (1 => Directory_Separator);
               else
 
                  if Fold_To_Lower_Case then
                     System.Case_Util.To_Lower (Path_Buffer (1 .. Last - 1));
                  end if;
 
                  return Path_Buffer (1 .. Last - 1);
 
               end if;
 
            else
               Path_Buffer (Last + 1 .. End_Path - 2) :=
                 Path_Buffer (Last + 3 .. End_Path);
               End_Path := End_Path - 2;
            end if;
 
         --  Remove ".." fields
 
         elsif Finish = Start + 1
           and then Path_Buffer (Start .. Finish) = ".."
         then
            Start := Last;
            loop
               Start := Start - 1;
               exit when Start < 1 or else
                 Path_Buffer (Start) = Directory_Separator;
            end loop;
 
            if Start <= 1 then
               if Finish = End_Path then
                  return (1 => Directory_Separator);
 
               else
                  Path_Buffer (1 .. End_Path - Finish) :=
                    Path_Buffer (Finish + 1 .. End_Path);
                  End_Path := End_Path - Finish;
                  Last := 1;
               end if;
 
            else
               if Finish = End_Path then
                  return Final_Value (Path_Buffer (1 .. Start - 1));
 
               else
                  Path_Buffer (Start + 1 .. Start + End_Path - Finish - 1) :=
                    Path_Buffer (Finish + 2 .. End_Path);
                  End_Path := Start + End_Path - Finish - 1;
                  Last := Start;
               end if;
            end if;
 
         --  Check if current field is a symbolic link
 
         elsif Resolve_Links then
            declare
               Saved : constant Character := Path_Buffer (Finish + 1);
 
            begin
               Path_Buffer (Finish + 1) := ASCII.NUL;
               Status := Readlink (Path_Buffer'Address,
                                   Link_Buffer'Address,
                                   Link_Buffer'Length);
               Path_Buffer (Finish + 1) := Saved;
            end;
 
            --  Not a symbolic link, move to the next field, if any
 
            if Status <= 0 then
               Last := Finish + 1;
 
            --  Replace symbolic link with its value
 
            else
               if Is_Absolute_Path (Link_Buffer (1 .. Status)) then
                  Path_Buffer (Status + 1 .. End_Path - (Finish - Status)) :=
                  Path_Buffer (Finish + 1 .. End_Path);
                  End_Path := End_Path - (Finish - Status);
                  Path_Buffer (1 .. Status) := Link_Buffer (1 .. Status);
                  Last := 1;
 
               else
                  Path_Buffer
                    (Last + Status + 1 .. End_Path - Finish + Last + Status) :=
                    Path_Buffer (Finish + 1 .. End_Path);
                  End_Path := End_Path - Finish + Last + Status;
                  Path_Buffer (Last + 1 .. Last + Status) :=
                    Link_Buffer (1 .. Status);
               end if;
            end if;
 
         else
            Last := Finish + 1;
         end if;
      end loop;
 
      --  Too many iterations: give up
 
      --  This can happen when there is a circularity in the symbolic links: A
      --  is a symbolic link for B, which itself is a symbolic link, and the
      --  target of B or of another symbolic link target of B is A. In this
      --  case, we return an empty string to indicate failure to resolve.
 
      return "";
   end Normalize_Pathname;
 
   ---------------
   -- Open_Read --
   ---------------
 
   function Open_Read
     (Name  : C_File_Name;
      Fmode : Mode) return File_Descriptor
   is
      function C_Open_Read
        (Name  : C_File_Name;
         Fmode : Mode) return File_Descriptor;
      pragma Import (C, C_Open_Read, "__gnat_open_read");
   begin
      return C_Open_Read (Name, Fmode);
   end Open_Read;
 
   function Open_Read
     (Name  : String;
      Fmode : Mode) return File_Descriptor
   is
      C_Name : String (1 .. Name'Length + 1);
   begin
      C_Name (1 .. Name'Length) := Name;
      C_Name (C_Name'Last)      := ASCII.NUL;
      return Open_Read (C_Name (C_Name'First)'Address, Fmode);
   end Open_Read;
 
   ---------------------
   -- Open_Read_Write --
   ---------------------
 
   function Open_Read_Write
     (Name  : C_File_Name;
      Fmode : Mode) return File_Descriptor
   is
      function C_Open_Read_Write
        (Name  : C_File_Name;
         Fmode : Mode) return File_Descriptor;
      pragma Import (C, C_Open_Read_Write, "__gnat_open_rw");
   begin
      return C_Open_Read_Write (Name, Fmode);
   end Open_Read_Write;
 
   function Open_Read_Write
     (Name  : String;
      Fmode : Mode) return File_Descriptor
   is
      C_Name : String (1 .. Name'Length + 1);
   begin
      C_Name (1 .. Name'Length) := Name;
      C_Name (C_Name'Last)      := ASCII.NUL;
      return Open_Read_Write (C_Name (C_Name'First)'Address, Fmode);
   end Open_Read_Write;
 
   -------------
   -- OS_Exit --
   -------------
 
   procedure OS_Exit (Status : Integer) is
   begin
      OS_Exit_Ptr (Status);
      raise Program_Error;
   end OS_Exit;
 
   ---------------------
   -- OS_Exit_Default --
   ---------------------
 
   procedure OS_Exit_Default (Status : Integer) is
      procedure GNAT_OS_Exit (Status : Integer);
      pragma Import (C, GNAT_OS_Exit, "__gnat_os_exit");
      pragma No_Return (GNAT_OS_Exit);
   begin
      GNAT_OS_Exit (Status);
   end OS_Exit_Default;
 
   --------------------
   -- Pid_To_Integer --
   --------------------
 
   function Pid_To_Integer (Pid : Process_Id) return Integer is
   begin
      return Integer (Pid);
   end Pid_To_Integer;
 
   ----------
   -- Read --
   ----------
 
   function Read
     (FD : File_Descriptor;
      A  : System.Address;
      N  : Integer) return Integer
   is
   begin
      return Integer (System.CRTL.read
        (System.CRTL.int (FD), System.CRTL.chars (A), System.CRTL.int (N)));
   end Read;
 
   -----------------
   -- Rename_File --
   -----------------
 
   procedure Rename_File
     (Old_Name : C_File_Name;
      New_Name : C_File_Name;
      Success  : out Boolean)
   is
      function rename (From, To : Address) return Integer;
      pragma Import (C, rename, "__gnat_rename");
      R : Integer;
   begin
      R := rename (Old_Name, New_Name);
      Success := (R = 0);
   end Rename_File;
 
   procedure Rename_File
     (Old_Name : String;
      New_Name : String;
      Success  : out Boolean)
   is
      C_Old_Name : String (1 .. Old_Name'Length + 1);
      C_New_Name : String (1 .. New_Name'Length + 1);
   begin
      C_Old_Name (1 .. Old_Name'Length) := Old_Name;
      C_Old_Name (C_Old_Name'Last)      := ASCII.NUL;
      C_New_Name (1 .. New_Name'Length) := New_Name;
      C_New_Name (C_New_Name'Last)      := ASCII.NUL;
      Rename_File (C_Old_Name'Address, C_New_Name'Address, Success);
   end Rename_File;
 
   -----------------------
   -- Set_Close_On_Exec --
   -----------------------
 
   procedure Set_Close_On_Exec
     (FD            : File_Descriptor;
      Close_On_Exec : Boolean;
      Status        : out Boolean)
   is
      function C_Set_Close_On_Exec
        (FD : File_Descriptor; Close_On_Exec : System.CRTL.int)
         return System.CRTL.int;
      pragma Import (C, C_Set_Close_On_Exec, "__gnat_set_close_on_exec");
   begin
      Status := C_Set_Close_On_Exec (FD, Boolean'Pos (Close_On_Exec)) = 0;
   end Set_Close_On_Exec;
 
   --------------------
   -- Set_Executable --
   --------------------
 
   procedure Set_Executable (Name : String) is
      procedure C_Set_Executable (Name : C_File_Name);
      pragma Import (C, C_Set_Executable, "__gnat_set_executable");
      C_Name : aliased String (Name'First .. Name'Last + 1);
   begin
      C_Name (Name'Range)  := Name;
      C_Name (C_Name'Last) := ASCII.NUL;
      C_Set_Executable (C_Name (C_Name'First)'Address);
   end Set_Executable;
 
   ----------------------
   -- Set_Non_Readable --
   ----------------------
 
   procedure Set_Non_Readable (Name : String) is
      procedure C_Set_Non_Readable (Name : C_File_Name);
      pragma Import (C, C_Set_Non_Readable, "__gnat_set_non_readable");
      C_Name : aliased String (Name'First .. Name'Last + 1);
   begin
      C_Name (Name'Range)  := Name;
      C_Name (C_Name'Last) := ASCII.NUL;
      C_Set_Non_Readable (C_Name (C_Name'First)'Address);
   end Set_Non_Readable;
 
   ----------------------
   -- Set_Non_Writable --
   ----------------------
 
   procedure Set_Non_Writable (Name : String) is
      procedure C_Set_Non_Writable (Name : C_File_Name);
      pragma Import (C, C_Set_Non_Writable, "__gnat_set_non_writable");
      C_Name : aliased String (Name'First .. Name'Last + 1);
   begin
      C_Name (Name'Range)  := Name;
      C_Name (C_Name'Last) := ASCII.NUL;
      C_Set_Non_Writable (C_Name (C_Name'First)'Address);
   end Set_Non_Writable;
 
   ------------------
   -- Set_Readable --
   ------------------
 
   procedure Set_Readable (Name : String) is
      procedure C_Set_Readable (Name : C_File_Name);
      pragma Import (C, C_Set_Readable, "__gnat_set_readable");
      C_Name : aliased String (Name'First .. Name'Last + 1);
   begin
      C_Name (Name'Range)  := Name;
      C_Name (C_Name'Last) := ASCII.NUL;
      C_Set_Readable (C_Name (C_Name'First)'Address);
   end Set_Readable;
 
   --------------------
   -- Set_Writable --
   --------------------
 
   procedure Set_Writable (Name : String) is
      procedure C_Set_Writable (Name : C_File_Name);
      pragma Import (C, C_Set_Writable, "__gnat_set_writable");
      C_Name : aliased String (Name'First .. Name'Last + 1);
   begin
      C_Name (Name'Range)  := Name;
      C_Name (C_Name'Last) := ASCII.NUL;
      C_Set_Writable (C_Name (C_Name'First)'Address);
   end Set_Writable;
 
   ------------
   -- Setenv --
   ------------
 
   procedure Setenv (Name : String; Value : String) is
      F_Name  : String (1 .. Name'Length + 1);
      F_Value : String (1 .. Value'Length + 1);
 
      procedure Set_Env_Value (Name, Value : System.Address);
      pragma Import (C, Set_Env_Value, "__gnat_setenv");
 
   begin
      F_Name (1 .. Name'Length) := Name;
      F_Name (F_Name'Last)      := ASCII.NUL;
 
      F_Value (1 .. Value'Length) := Value;
      F_Value (F_Value'Last)      := ASCII.NUL;
 
      Set_Env_Value (F_Name'Address, F_Value'Address);
   end Setenv;
 
   -----------
   -- Spawn --
   -----------
 
   function Spawn
     (Program_Name : String;
      Args         : Argument_List) return Integer
   is
      Result : Integer;
      Junk   : Process_Id;
      pragma Warnings (Off, Junk);
   begin
      Spawn_Internal (Program_Name, Args, Result, Junk, Blocking => True);
      return Result;
   end Spawn;
 
   procedure Spawn
     (Program_Name : String;
      Args         : Argument_List;
      Success      : out Boolean)
   is
   begin
      Success := (Spawn (Program_Name, Args) = 0);
   end Spawn;
 
   procedure Spawn
     (Program_Name           : String;
      Args                   : Argument_List;
      Output_File_Descriptor : File_Descriptor;
      Return_Code            : out Integer;
      Err_To_Out             : Boolean := True)
   is
      Saved_Output : File_Descriptor;
      Saved_Error  : File_Descriptor := Invalid_FD; -- prevent compiler warning
 
   begin
      --  Set standard output and error to the temporary file
 
      Saved_Output := Dup (Standout);
      Dup2 (Output_File_Descriptor, Standout);
 
      if Err_To_Out then
         Saved_Error  := Dup (Standerr);
         Dup2 (Output_File_Descriptor, Standerr);
      end if;
 
      --  Spawn the program
 
      Return_Code := Spawn (Program_Name, Args);
 
      --  Restore the standard output and error
 
      Dup2 (Saved_Output, Standout);
 
      if Err_To_Out then
         Dup2 (Saved_Error, Standerr);
      end if;
 
      --  And close the saved standard output and error file descriptors
 
      Close (Saved_Output);
 
      if Err_To_Out then
         Close (Saved_Error);
      end if;
   end Spawn;
 
   procedure Spawn
     (Program_Name : String;
      Args         : Argument_List;
      Output_File  : String;
      Success      : out Boolean;
      Return_Code  : out Integer;
      Err_To_Out   : Boolean := True)
   is
      FD : File_Descriptor;
 
   begin
      Success := True;
      Return_Code := 0;
 
      FD := Create_Output_Text_File (Output_File);
 
      if FD = Invalid_FD then
         Success := False;
         return;
      end if;
 
      Spawn (Program_Name, Args, FD, Return_Code, Err_To_Out);
 
      Close (FD, Success);
   end Spawn;
 
   --------------------
   -- Spawn_Internal --
   --------------------
 
   procedure Spawn_Internal
     (Program_Name : String;
      Args         : Argument_List;
      Result       : out Integer;
      Pid          : out Process_Id;
      Blocking     : Boolean)
   is
 
      procedure Spawn (Args : Argument_List);
      --  Call Spawn with given argument list
 
      N_Args : Argument_List (Args'Range);
      --  Normalized arguments
 
      -----------
      -- Spawn --
      -----------
 
      procedure Spawn (Args : Argument_List) is
         type Chars is array (Positive range <>) of aliased Character;
         type Char_Ptr is access constant Character;
 
         Command_Len  : constant Positive := Program_Name'Length + 1
                                               + Args_Length (Args);
         Command_Last : Natural := 0;
         Command      : aliased Chars (1 .. Command_Len);
         --  Command contains all characters of the Program_Name and Args, all
         --  terminated by ASCII.NUL characters.
 
         Arg_List_Len  : constant Positive := Args'Length + 2;
         Arg_List_Last : Natural := 0;
         Arg_List      : aliased array (1 .. Arg_List_Len) of Char_Ptr;
         --  List with pointers to NUL-terminated strings of the Program_Name
         --  and the Args and terminated with a null pointer. We rely on the
         --  default initialization for the last null pointer.
 
         procedure Add_To_Command (S : String);
         --  Add S and a NUL character to Command, updating Last
 
         function Portable_Spawn (Args : Address) return Integer;
         pragma Import (C, Portable_Spawn, "__gnat_portable_spawn");
 
         function Portable_No_Block_Spawn (Args : Address) return Process_Id;
         pragma Import
           (C, Portable_No_Block_Spawn, "__gnat_portable_no_block_spawn");
 
         --------------------
         -- Add_To_Command --
         --------------------
 
         procedure Add_To_Command (S : String) is
            First : constant Natural := Command_Last + 1;
 
         begin
            Command_Last := Command_Last + S'Length;
 
            --  Move characters one at a time, because Command has aliased
            --  components.
 
            --  But not volatile, so why is this necessary ???
 
            for J in S'Range loop
               Command (First + J - S'First) := S (J);
            end loop;
 
            Command_Last := Command_Last + 1;
            Command (Command_Last) := ASCII.NUL;
 
            Arg_List_Last := Arg_List_Last + 1;
            Arg_List (Arg_List_Last) := Command (First)'Access;
         end Add_To_Command;
 
      --  Start of processing for Spawn
 
      begin
         Add_To_Command (Program_Name);
 
         for J in Args'Range loop
            Add_To_Command (Args (J).all);
         end loop;
 
         if Blocking then
            Pid     := Invalid_Pid;
            Result  := Portable_Spawn (Arg_List'Address);
         else
            Pid     := Portable_No_Block_Spawn (Arg_List'Address);
            Result  := Boolean'Pos (Pid /= Invalid_Pid);
         end if;
      end Spawn;
 
   --  Start of processing for Spawn_Internal
 
   begin
      --  Copy arguments into a local structure
 
      for K in N_Args'Range loop
         N_Args (K) := new String'(Args (K).all);
      end loop;
 
      --  Normalize those arguments
 
      Normalize_Arguments (N_Args);
 
      --  Call spawn using the normalized arguments
 
      Spawn (N_Args);
 
      --  Free arguments list
 
      for K in N_Args'Range loop
         Free (N_Args (K));
      end loop;
   end Spawn_Internal;
 
   ---------------------------
   -- To_Path_String_Access --
   ---------------------------
 
   function To_Path_String_Access
     (Path_Addr : Address;
      Path_Len  : Integer) return String_Access
   is
      subtype Path_String is String (1 .. Path_Len);
      type    Path_String_Access is access Path_String;
 
      function Address_To_Access is new Ada.Unchecked_Conversion
        (Source => Address, Target => Path_String_Access);
 
      Path_Access : constant Path_String_Access :=
                      Address_To_Access (Path_Addr);
 
      Return_Val  : String_Access;
 
   begin
      Return_Val := new String (1 .. Path_Len);
 
      for J in 1 .. Path_Len loop
         Return_Val (J) := Path_Access (J);
      end loop;
 
      return Return_Val;
   end To_Path_String_Access;
 
   ------------------
   -- Wait_Process --
   ------------------
 
   procedure Wait_Process (Pid : out Process_Id; Success : out Boolean) is
      Status : Integer;
 
      function Portable_Wait (S : Address) return Process_Id;
      pragma Import (C, Portable_Wait, "__gnat_portable_wait");
 
   begin
      Pid := Portable_Wait (Status'Address);
      Success := (Status = 0);
   end Wait_Process;
 
   -----------
   -- Write --
   -----------
 
   function Write
     (FD : File_Descriptor;
      A  : System.Address;
      N  : Integer) return Integer
   is
   begin
      return Integer (System.CRTL.write
        (System.CRTL.int (FD), System.CRTL.chars (A), System.CRTL.int (N)));
   end Write;
 
end System.OS_Lib;
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[/] [openrisc/] [trunk/] [gnu-src/] [gcc-4.5.1/] [gcc/] [ada/] [s-os_lib.adb] - Blame information for rev 281

Line No.	Rev	Author	Line
1	281	jeremybenn	`------------------------------------------------------------------------------`
2			`-- --`
3			`-- GNAT COMPILER COMPONENTS --`
4			`-- --`
5			`-- S Y S T E M . O S _ L I B --`
6			`-- --`
7			`-- B o d y --`
8			`-- --`
9			`-- Copyright (C) 1995-2009, AdaCore --`
10			`-- --`
11			`-- GNAT is free software; you can redistribute it and/or modify it under --`
12			`-- terms of the GNU General Public License as published by the Free Soft- --`
13			`-- ware Foundation; either version 2, or (at your option) any later ver- --`
14			`-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --`
15			`-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --`
16			`-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --`
17			`-- for more details. You should have received a copy of the GNU General --`
18			`-- Public License distributed with GNAT; see file COPYING. If not, write --`
19			`-- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --`
20			`-- Boston, MA 02110-1301, USA. --`
21			`-- --`
22			`-- As a special exception, if other files instantiate generics from this --`
23			`-- unit, or you link this unit with other files to produce an executable, --`
24			`-- this unit does not by itself cause the resulting executable to be --`
25			`-- covered by the GNU General Public License. This exception does not --`
26			`-- however invalidate any other reasons why the executable file might be --`
27			`-- covered by the GNU Public License. --`
28			`-- --`
29			`-- GNAT was originally developed by the GNAT team at New York University. --`
30			`-- Extensive contributions were provided by Ada Core Technologies Inc. --`
31			`-- --`
32			`------------------------------------------------------------------------------`
33
34			`pragma Compiler_Unit;`
35
36			`with System.Case_Util;`
37			`with System.CRTL;`
38			`with System.Soft_Links;`
39			`with Ada.Unchecked_Conversion;`
40			`with Ada.Unchecked_Deallocation;`