1 ------------------------------------------------------------------------------
3 -- GNAT RUN-TIME COMPONENTS --
5 -- S Y S T E M . F I L E _ I O --
11 -- Copyright (C) 1992-2002 Free Software Foundation, Inc. --
13 -- GNAT is free software; you can redistribute it and/or modify it under --
14 -- terms of the GNU General Public License as published by the Free Soft- --
15 -- ware Foundation; either version 2, or (at your option) any later ver- --
16 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
17 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
18 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
19 -- for more details. You should have received a copy of the GNU General --
20 -- Public License distributed with GNAT; see file COPYING. If not, write --
21 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
22 -- MA 02111-1307, USA. --
24 -- As a special exception, if other files instantiate generics from this --
25 -- unit, or you link this unit with other files to produce an executable, --
26 -- this unit does not by itself cause the resulting executable to be --
27 -- covered by the GNU General Public License. This exception does not --
28 -- however invalidate any other reasons why the executable file might be --
29 -- covered by the GNU Public License. --
31 -- GNAT was originally developed by the GNAT team at New York University. --
32 -- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
34 ------------------------------------------------------------------------------
36 with Ada.Finalization; use Ada.Finalization;
37 with Ada.IO_Exceptions; use Ada.IO_Exceptions;
38 with Interfaces.C_Streams; use Interfaces.C_Streams;
39 with System.Soft_Links;
40 with Unchecked_Deallocation;
42 package body System.File_IO is
44 use System.File_Control_Block;
46 package SSL renames System.Soft_Links;
48 ----------------------
49 -- Global Variables --
50 ----------------------
52 Open_Files : AFCB_Ptr;
53 -- This points to a list of AFCB's for all open files. This is a doubly
54 -- linked list, with the Prev pointer of the first entry, and the Next
55 -- pointer of the last entry containing null. Note that this global
56 -- variable must be properly protected to provide thread safety.
58 type Temp_File_Record;
59 type Temp_File_Record_Ptr is access all Temp_File_Record;
61 type Temp_File_Record is record
62 Name : String (1 .. L_tmpnam + 1);
63 Next : Temp_File_Record_Ptr;
65 -- One of these is allocated for each temporary file created
67 Temp_Files : Temp_File_Record_Ptr;
68 -- Points to list of names of temporary files. Note that this global
69 -- variable must be properly protected to provide thread safety.
71 type File_IO_Clean_Up_Type is new Controlled with null record;
72 -- The closing of all open files and deletion of temporary files is an
73 -- action which takes place at the end of execution of the main program.
74 -- This action can be implemented using a library level object which
75 -- gets finalized at the end of the main program execution. The above is
76 -- a controlled type introduced for this purpose.
78 procedure Finalize (V : in out File_IO_Clean_Up_Type);
79 -- This is the finalize operation that is used to do the cleanup.
81 File_IO_Clean_Up_Object : File_IO_Clean_Up_Type;
82 pragma Warnings (Off, File_IO_Clean_Up_Object);
83 -- This is the single object of the type that triggers the finalization
84 -- call. Since it is at the library level, this happens just before the
85 -- environment task is finalized.
87 text_translation_required : Boolean;
89 (C, text_translation_required, "__gnat_text_translation_required");
90 -- If true, add appropriate suffix to control string for Open.
92 -----------------------
93 -- Local Subprograms --
94 -----------------------
96 procedure Free_String is new Unchecked_Deallocation (String, Pstring);
98 subtype Fopen_String is String (1 .. 4);
99 -- Holds open string (longest is "w+b" & nul)
106 Fopstr : out Fopen_String);
107 -- Determines proper open mode for a file to be opened in the given
108 -- Ada mode. Text is true for a text file and false otherwise, and
109 -- Creat is true for a create call, and False for an open call. The
110 -- value stored in Fopstr is a nul-terminated string suitable for a
111 -- call to fopen or freopen. Amethod is the character designating
112 -- the access method from the Access_Method field of the FCB.
118 procedure Append_Set (File : AFCB_Ptr) is
120 if File.Mode = Append_File then
121 if fseek (File.Stream, 0, SEEK_END) /= 0 then
131 procedure Chain_File (File : AFCB_Ptr) is
133 -- Take a task lock, to protect the global data value Open_Files
134 -- No exception handler needed, since we cannot get an exception.
137 File.Next := Open_Files;
141 if File.Next /= null then
142 File.Next.Prev := File;
148 ---------------------
149 -- Check_File_Open --
150 ---------------------
152 procedure Check_File_Open (File : AFCB_Ptr) is
159 -----------------------
160 -- Check_Read_Status --
161 -----------------------
163 procedure Check_Read_Status (File : AFCB_Ptr) is
167 elsif File.Mode > Inout_File then
170 end Check_Read_Status;
172 ------------------------
173 -- Check_Write_Status --
174 ------------------------
176 procedure Check_Write_Status (File : AFCB_Ptr) is
180 elsif File.Mode = In_File then
183 end Check_Write_Status;
189 procedure Close (File : in out AFCB_Ptr) is
190 Close_Status : int := 0;
191 Dup_Strm : Boolean := False;
194 Check_File_Open (File);
197 -- Sever the association between the given file and its associated
198 -- external file. The given file is left closed. Do not perform system
199 -- closes on the standard input, output and error files and also do
200 -- not attempt to close a stream that does not exist (signalled by a
201 -- null stream value -- happens in some error situations).
203 if not File.Is_System_File
204 and then File.Stream /= NULL_Stream
206 -- Do not do an fclose if this is a shared file and there is
207 -- at least one other instance of the stream that is open.
209 if File.Shared_Status = Yes then
217 and then File.Stream = P.Stream
228 -- Do the fclose unless this was a duplicate in the shared case
231 Close_Status := fclose (File.Stream);
235 -- Dechain file from list of open files and then free the storage
236 -- Since this is a global data structure, we have to protect against
237 -- multiple tasks attempting to access this list.
239 -- Note that we do not use an exception handler to unlock here since
240 -- no exception can occur inside the lock/unlock pair.
245 if File.Prev = null then
246 Open_Files := File.Next;
248 File.Prev.Next := File.Next;
251 if File.Next /= null then
252 File.Next.Prev := File.Prev;
258 -- Deallocate some parts of the file structure that were kept in heap
259 -- storage with the exception of system files (standard input, output
260 -- and error) since they had some information allocated in the stack.
262 if not File.Is_System_File then
263 Free_String (File.Name);
264 Free_String (File.Form);
270 if Close_Status /= 0 then
279 procedure Delete (File : in out AFCB_Ptr) is
281 Check_File_Open (File);
283 if not File.Is_Regular_File then
288 Filename : aliased constant String := File.Name.all;
293 -- Now unlink the external file. Note that we use the full name
294 -- in this unlink, because the working directory may have changed
295 -- since we did the open, and we want to unlink the right file!
297 if unlink (Filename'Address) = -1 then
307 function End_Of_File (File : AFCB_Ptr) return Boolean is
309 Check_File_Open (File);
311 if feof (File.Stream) /= 0 then
315 Check_Read_Status (File);
317 if ungetc (fgetc (File.Stream), File.Stream) = EOF then
318 clearerr (File.Stream);
330 -- Note: we do not need to worry about locking against multiple task
331 -- access in this routine, since it is called only from the environment
332 -- task just before terminating execution.
334 procedure Finalize (V : in out File_IO_Clean_Up_Type) is
335 pragma Warnings (Off, V);
342 -- First close all open files (the slightly complex form of this loop
343 -- is required because Close as a side effect nulls out its argument)
346 while Fptr1 /= null loop
352 -- Now unlink all temporary files. We do not bother to free the
353 -- blocks because we are just about to terminate the program. We
354 -- also ignore any errors while attempting these unlink operations.
356 while Temp_Files /= null loop
357 Discard := unlink (Temp_Files.Name'Address);
358 Temp_Files := Temp_Files.Next;
367 procedure Flush (File : AFCB_Ptr) is
369 Check_Write_Status (File);
371 if fflush (File.Stream) = 0 then
382 -- The fopen mode to be used is shown by the following table:
385 -- Append_File "r+" "w+"
387 -- Out_File (Direct_IO) "r+" "w"
388 -- Out_File (all others) "w" "w"
389 -- Inout_File "r+" "w+"
391 -- Note: we do not use "a" or "a+" for Append_File, since this would not
392 -- work in the case of stream files, where even if in append file mode,
393 -- you can reset to earlier points in the file. The caller must use the
394 -- Append_Set routine to deal with the necessary positioning.
396 -- Note: in several cases, the fopen mode used allows reading and
397 -- writing, but the setting of the Ada mode is more restrictive. For
398 -- instance, Create in In_File mode uses "w+" which allows writing,
399 -- but the Ada mode In_File will cause any write operations to be
400 -- rejected with Mode_Error in any case.
402 -- Note: for the Out_File/Open cases for other than the Direct_IO case,
403 -- an initial call will be made by the caller to first open the file in
404 -- "r" mode to be sure that it exists. The real open, in "w" mode, will
405 -- then destroy this file. This is peculiar, but that's what Ada semantics
406 -- require and the ACVT tests insist on!
408 -- If text file translation is required, then either b or t is
409 -- added to the mode, depending on the setting of Text.
416 Fopstr : out Fopen_String)
433 if Amethod = 'D' and not Creat then
442 when Inout_File | Append_File =>
454 -- If text_translation_required is true then we need to append
455 -- either a t or b to the string to get the right mode
457 if text_translation_required then
459 Fopstr (Fptr) := 't';
461 Fopstr (Fptr) := 'b';
467 Fopstr (Fptr) := ASCII.NUL;
474 function Form (File : in AFCB_Ptr) return String is
479 return File.Form.all (1 .. File.Form'Length - 1);
487 function Form_Boolean
496 Form_Parameter (Form, Keyword, V1, V2);
501 elsif Form (V1) = 'y' then
504 elsif Form (V1) = 'n' then
516 function Form_Integer
526 Form_Parameter (Form, Keyword, V1, V2);
534 for J in V1 .. V2 loop
535 if Form (J) not in '0' .. '9' then
538 V := V * 10 + Character'Pos (Form (J)) - Character'Pos ('0');
554 procedure Form_Parameter
560 Klen : constant Integer := Keyword'Length;
562 -- Start of processing for Form_Parameter
565 for J in Form'First + Klen .. Form'Last - 1 loop
567 and then Form (J - Klen .. J - 1) = Keyword
572 while Form (Stop + 1) /= ASCII.NUL
573 and then Form (Stop + 1) /= ','
590 function Is_Open (File : in AFCB_Ptr) return Boolean is
592 return (File /= null);
599 procedure Make_Buffered
601 Buf_Siz : Interfaces.C_Streams.size_t) is
605 status := setvbuf (File.Stream, Null_Address, IOFBF, Buf_Siz);
608 ------------------------
609 -- Make_Line_Buffered --
610 ------------------------
612 procedure Make_Line_Buffered
614 Line_Siz : Interfaces.C_Streams.size_t) is
618 status := setvbuf (File.Stream, Null_Address, IOLBF, Line_Siz);
619 end Make_Line_Buffered;
621 ---------------------
622 -- Make_Unbuffered --
623 ---------------------
625 procedure Make_Unbuffered (File : AFCB_Ptr) is
629 status := setvbuf (File.Stream, Null_Address, IONBF, 0);
636 function Mode (File : in AFCB_Ptr) return File_Mode is
649 function Name (File : in AFCB_Ptr) return String is
654 return File.Name.all (1 .. File.Name'Length - 1);
663 (File_Ptr : in out AFCB_Ptr;
664 Dummy_FCB : in out AFCB'Class;
671 C_Stream : FILEs := NULL_Stream)
673 procedure Tmp_Name (Buffer : Address);
674 pragma Import (C, Tmp_Name, "__gnat_tmp_name");
675 -- set buffer (a String address) with a temporary filename.
677 Stream : FILEs := C_Stream;
678 -- Stream which we open in response to this request
680 Shared : Shared_Status_Type;
681 -- Setting of Shared_Status field for file
683 Fopstr : aliased Fopen_String;
684 -- Mode string used in fopen call
686 Formstr : aliased String (1 .. Form'Length + 1);
687 -- Form string with ASCII.NUL appended, folded to lower case
689 Tempfile : constant Boolean := (Name'Length = 0);
690 -- Indicates temporary file case
692 Namelen : constant Integer := max_path_len;
693 -- Length required for file name, not including final ASCII.NUL
694 -- Note that we used to reference L_tmpnam here, which is not
695 -- reliable since __gnat_tmp_name does not always use tmpnam.
697 Namestr : aliased String (1 .. Namelen + 1);
698 -- Name as given or temporary file name with ASCII.NUL appended
700 Fullname : aliased String (1 .. max_path_len + 1);
701 -- Full name (as required for Name function, and as stored in the
702 -- control block in the Name field) with ASCII.NUL appended.
704 Full_Name_Len : Integer;
705 -- Length of name actually stored in Fullname
708 if File_Ptr /= null then
712 -- Acquire form string, setting required NUL terminator
714 Formstr (1 .. Form'Length) := Form;
715 Formstr (Formstr'Last) := ASCII.NUL;
717 -- Convert form string to lower case
719 for J in Formstr'Range loop
720 if Formstr (J) in 'A' .. 'Z' then
721 Formstr (J) := Character'Val (Character'Pos (Formstr (J)) + 32);
725 -- Acquire setting of shared parameter
731 Form_Parameter (Formstr, "shared", V1, V2);
736 elsif Formstr (V1 .. V2) = "yes" then
739 elsif Formstr (V1 .. V2) = "no" then
747 -- If we were given a stream (call from xxx.C_Streams.Open), then set
748 -- full name to null and that is all we have to do in this case so
749 -- skip to end of processing.
751 if Stream /= NULL_Stream then
752 Fullname (1) := ASCII.Nul;
755 -- Normal case of Open or Create
758 -- If temporary file case, get temporary file name and add
759 -- to the list of temporary files to be deleted on exit.
766 Tmp_Name (Namestr'Address);
768 if Namestr (1) = ASCII.NUL then
772 -- Chain to temp file list, ensuring thread safety with a lock
777 new Temp_File_Record'(Name => Namestr, Next => Temp_Files);
786 -- Normal case of non-null name given
789 Namestr (1 .. Name'Length) := Name;
790 Namestr (Name'Length + 1) := ASCII.NUL;
793 -- Get full name in accordance with the advice of RM A.8.2(22).
795 full_name (Namestr'Address, Fullname'Address);
797 if Fullname (1) = ASCII.NUL then
802 while Full_Name_Len < Fullname'Last
803 and then Fullname (Full_Name_Len) /= ASCII.NUL
805 Full_Name_Len := Full_Name_Len + 1;
808 -- If Shared=None or Shared=Yes, then check for the existence
809 -- of another file with exactly the same full name.
818 if Fullname (1 .. Full_Name_Len) = P.Name.all then
820 -- If we get a match, and either file has Shared=None,
821 -- then raise Use_Error, since we don't allow two
822 -- files of the same name to be opened unless they
823 -- specify the required sharing mode.
826 or else P.Shared_Status = None
830 -- If both files have Shared=Yes, then we acquire the
831 -- stream from the located file to use as our stream.
834 and then P.Shared_Status = Yes
839 -- Otherwise one of the files has Shared=Yes and one
840 -- has Shared=No. If the current file has Shared=No
841 -- then all is well but we don't want to share any
842 -- other file's stream. If the current file has
843 -- Shared=Yes, we would like to share a stream, but
844 -- not from a file that has Shared=No, so in either
845 -- case we just keep going on the search.
857 -- Open specified file if we did not find an existing stream
859 if Stream = NULL_Stream then
860 Fopen_Mode (Mode, Text, Creat, Amethod, Fopstr);
862 -- A special case, if we are opening (OPEN case) a file and
863 -- the mode returned by Fopen_Mode is not "r" or "r+", then
864 -- we first make sure that the file exists as required by
867 if Creat = False and then Fopstr (1) /= 'r' then
868 if file_exists (Namestr'Address) = 0 then
873 -- Now open the file. Note that we use the name as given
874 -- in the original Open call for this purpose, since that
875 -- seems the clearest implementation of the intent. It
876 -- would presumably work to use the full name here, but
877 -- if there is any difference, then we should use the
878 -- name used in the call.
880 -- Note: for a corresponding delete, we will use the
881 -- full name, since by the time of the delete, the
882 -- current working directory may have changed and
883 -- we do not want to delete a different file!
885 Stream := fopen (Namestr'Address, Fopstr'Address);
887 if Stream = NULL_Stream then
888 if file_exists (Namestr'Address) = 0 then
897 -- Stream has been successfully located or opened, so now we are
898 -- committed to completing the opening of the file. Allocate block
899 -- on heap and fill in its fields.
901 File_Ptr := AFCB_Allocate (Dummy_FCB);
903 File_Ptr.Is_Regular_File := (is_regular_file
904 (fileno (Stream)) /= 0);
905 File_Ptr.Is_System_File := False;
906 File_Ptr.Is_Text_File := Text;
907 File_Ptr.Shared_Status := Shared;
908 File_Ptr.Access_Method := Amethod;
909 File_Ptr.Stream := Stream;
910 File_Ptr.Form := new String'(Formstr);
911 File_Ptr.Name := new String'(Fullname
912 (1 .. Full_Name_Len));
913 File_Ptr.Mode := Mode;
914 File_Ptr.Is_Temporary_File := Tempfile;
916 Chain_File (File_Ptr);
917 Append_Set (File_Ptr);
924 procedure Read_Buf (File : AFCB_Ptr; Buf : Address; Siz : size_t) is
928 Nread := fread (Buf, 1, Siz, File.Stream);
933 elsif ferror (File.Stream) /= 0 then
939 else -- 0 < Nread < Siz
948 Siz : in Interfaces.C_Streams.size_t;
949 Count : out Interfaces.C_Streams.size_t)
952 Count := fread (Buf, 1, Siz, File.Stream);
954 if Count = 0 and then ferror (File.Stream) /= 0 then
963 -- The reset which does not change the mode simply does a rewind.
965 procedure Reset (File : in out AFCB_Ptr) is
967 Check_File_Open (File);
968 Reset (File, File.Mode);
971 -- The reset with a change in mode is done using freopen, and is
972 -- not permitted except for regular files (since otherwise there
973 -- is no name for the freopen, and in any case it seems meaningless)
975 procedure Reset (File : in out AFCB_Ptr; Mode : in File_Mode) is
976 Fopstr : aliased Fopen_String;
979 Check_File_Open (File);
981 -- Change of mode not allowed for shared file or file with no name
982 -- or file that is not a regular file, or for a system file.
984 if File.Shared_Status = Yes
985 or else File.Name'Length <= 1
986 or else File.Is_System_File
987 or else (not File.Is_Regular_File)
991 -- For In_File or Inout_File for a regular file, we can just do a
992 -- rewind if the mode is unchanged, which is more efficient than
993 -- doing a full reopen.
995 elsif Mode = File.Mode
996 and then Mode <= Inout_File
998 rewind (File.Stream);
1000 -- Here the change of mode is permitted, we do it by reopening the
1001 -- file in the new mode and replacing the stream with a new stream.
1005 (Mode, File.Is_Text_File, False, File.Access_Method, Fopstr);
1008 freopen (File.Name.all'Address, Fopstr'Address, File.Stream);
1010 if File.Stream = NULL_Stream then
1025 procedure Write_Buf (File : AFCB_Ptr; Buf : Address; Siz : size_t) is
1027 -- Note: for most purposes, the Siz and 1 parameters in the fwrite
1028 -- call could be reversed, but on VMS, this is a better choice, since
1029 -- for some file formats, reversing the parameters results in records
1030 -- of one byte each.
1032 SSL.Abort_Defer.all;
1034 if fwrite (Buf, Siz, 1, File.Stream) /= 1 then
1036 SSL.Abort_Undefer.all;
1041 SSL.Abort_Undefer.all;