------------------------------------------------------------------------------ -- -- -- GNAT RUN-TIME COMPONENTS -- -- -- -- S Y S T E M . F I L E _ I O -- -- -- -- B o d y -- -- -- -- Copyright (C) 1992-2015, Free Software Foundation, Inc. -- -- -- -- GNAT is free software; you can redistribute it and/or modify it under -- -- terms of the GNU General Public License as published by the Free Soft- -- -- ware Foundation; either version 3, or (at your option) any later ver- -- -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- -- or FITNESS FOR A PARTICULAR PURPOSE. -- -- -- -- As a special exception under Section 7 of GPL version 3, you are granted -- -- additional permissions described in the GCC Runtime Library Exception, -- -- version 3.1, as published by the Free Software Foundation. -- -- -- -- You should have received a copy of the GNU General Public License and -- -- a copy of the GCC Runtime Library Exception along with this program; -- -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- -- . -- -- -- -- GNAT was originally developed by the GNAT team at New York University. -- -- Extensive contributions were provided by Ada Core Technologies Inc. -- -- -- ------------------------------------------------------------------------------ with Ada.Finalization; use Ada.Finalization; with Ada.IO_Exceptions; use Ada.IO_Exceptions; with Ada.Unchecked_Deallocation; with Interfaces.C; with Interfaces.C_Streams; use Interfaces.C_Streams; with System.Case_Util; use System.Case_Util; with System.CRTL; with System.OS_Lib; with System.Soft_Links; package body System.File_IO is use System.File_Control_Block; package SSL renames System.Soft_Links; use type CRTL.size_t; use type Interfaces.C.int; ---------------------- -- Global Variables -- ---------------------- Open_Files : AFCB_Ptr; -- This points to a list of AFCB's for all open files. This is a doubly -- linked list, with the Prev pointer of the first entry, and the Next -- pointer of the last entry containing null. Note that this global -- variable must be properly protected to provide thread safety. type Temp_File_Record; type Temp_File_Record_Ptr is access all Temp_File_Record; type Temp_File_Record is record Name : String (1 .. max_path_len + 1); Next : Temp_File_Record_Ptr; end record; -- One of these is allocated for each temporary file created Temp_Files : Temp_File_Record_Ptr; -- Points to list of names of temporary files. Note that this global -- variable must be properly protected to provide thread safety. type File_IO_Clean_Up_Type is new Limited_Controlled with null record; -- The closing of all open files and deletion of temporary files is an -- action that takes place at the end of execution of the main program. -- This action is implemented using a library level object which gets -- finalized at the end of program execution. Note that the type is -- limited, in order to stop the compiler optimizing away the declaration -- which would be allowed in the non-limited case. procedure Finalize (V : in out File_IO_Clean_Up_Type); -- This is the finalize operation that is used to do the cleanup File_IO_Clean_Up_Object : File_IO_Clean_Up_Type; pragma Warnings (Off, File_IO_Clean_Up_Object); -- This is the single object of the type that triggers the finalization -- call. Since it is at the library level, this happens just before the -- environment task is finalized. text_translation_required : Boolean; for text_translation_required'Size use Character'Size; pragma Import (C, text_translation_required, "__gnat_text_translation_required"); -- If true, add appropriate suffix to control string for Open ----------------------- -- Local Subprograms -- ----------------------- procedure Free_String is new Ada.Unchecked_Deallocation (String, Pstring); subtype Fopen_String is String (1 .. 4); -- Holds open string (longest is "w+b" & nul) procedure Fopen_Mode (Mode : File_Mode; Text : Boolean; Creat : Boolean; Amethod : Character; Fopstr : out Fopen_String); -- Determines proper open mode for a file to be opened in the given Ada -- mode. Text is true for a text file and false otherwise, and Creat is -- true for a create call, and False for an open call. The value stored -- in Fopstr is a nul-terminated string suitable for a call to fopen or -- freopen. Amethod is the character designating the access method from -- the Access_Method field of the FCB. function Errno_Message (Name : String; Errno : Integer := OS_Lib.Errno) return String; -- Return Errno_Message for Errno, with file name prepended procedure Raise_Device_Error (File : AFCB_Ptr; Errno : Integer := OS_Lib.Errno); pragma No_Return (Raise_Device_Error); -- Clear error indication on File and raise Device_Error with an exception -- message providing errno information. ---------------- -- Append_Set -- ---------------- procedure Append_Set (File : AFCB_Ptr) is begin if File.Mode = Append_File then if fseek (File.Stream, 0, SEEK_END) /= 0 then Raise_Device_Error (File); end if; end if; end Append_Set; ---------------- -- Chain_File -- ---------------- procedure Chain_File (File : AFCB_Ptr) is begin -- Take a task lock, to protect the global data value Open_Files SSL.Lock_Task.all; -- Do the chaining operation locked File.Next := Open_Files; File.Prev := null; Open_Files := File; if File.Next /= null then File.Next.Prev := File; end if; SSL.Unlock_Task.all; exception when others => SSL.Unlock_Task.all; raise; end Chain_File; --------------------- -- Check_File_Open -- --------------------- procedure Check_File_Open (File : AFCB_Ptr) is begin if File = null then raise Status_Error with "file not open"; end if; end Check_File_Open; ----------------------- -- Check_Read_Status -- ----------------------- procedure Check_Read_Status (File : AFCB_Ptr) is begin if File = null then raise Status_Error with "file not open"; elsif File.Mode not in Read_File_Mode then raise Mode_Error with "file not readable"; end if; end Check_Read_Status; ------------------------ -- Check_Write_Status -- ------------------------ procedure Check_Write_Status (File : AFCB_Ptr) is begin if File = null then raise Status_Error with "file not open"; elsif File.Mode = In_File then raise Mode_Error with "file not writable"; end if; end Check_Write_Status; ----------- -- Close -- ----------- procedure Close (File_Ptr : access AFCB_Ptr) is Close_Status : int := 0; Dup_Strm : Boolean := False; Errno : Integer := 0; File : AFCB_Ptr renames File_Ptr.all; begin -- Take a task lock, to protect the global data value Open_Files SSL.Lock_Task.all; Check_File_Open (File); AFCB_Close (File); -- Sever the association between the given file and its associated -- external file. The given file is left closed. Do not perform system -- closes on the standard input, output and error files and also do not -- attempt to close a stream that does not exist (signalled by a null -- stream value -- happens in some error situations). if not File.Is_System_File and then File.Stream /= NULL_Stream then -- Do not do an fclose if this is a shared file and there is at least -- one other instance of the stream that is open. if File.Shared_Status = Yes then declare P : AFCB_Ptr; begin P := Open_Files; while P /= null loop if P /= File and then File.Stream = P.Stream then Dup_Strm := True; exit; end if; P := P.Next; end loop; end; end if; -- Do the fclose unless this was a duplicate in the shared case if not Dup_Strm then Close_Status := fclose (File.Stream); if Close_Status /= 0 then Errno := OS_Lib.Errno; end if; end if; end if; -- Dechain file from list of open files and then free the storage if File.Prev = null then Open_Files := File.Next; else File.Prev.Next := File.Next; end if; if File.Next /= null then File.Next.Prev := File.Prev; end if; -- Deallocate some parts of the file structure that were kept in heap -- storage with the exception of system files (standard input, output -- and error) since they had some information allocated in the stack. if not File.Is_System_File then Free_String (File.Name); Free_String (File.Form); AFCB_Free (File); end if; File := null; if Close_Status /= 0 then Raise_Device_Error (null, Errno); end if; SSL.Unlock_Task.all; exception when others => SSL.Unlock_Task.all; raise; end Close; ------------ -- Delete -- ------------ procedure Delete (File_Ptr : access AFCB_Ptr) is File : AFCB_Ptr renames File_Ptr.all; begin Check_File_Open (File); if not File.Is_Regular_File then raise Use_Error with "cannot delete non-regular file"; end if; declare Filename : aliased constant String := File.Name.all; begin Close (File_Ptr); -- Now unlink the external file. Note that we use the full name in -- this unlink, because the working directory may have changed since -- we did the open, and we want to unlink the right file. if unlink (Filename'Address) = -1 then raise Use_Error with OS_Lib.Errno_Message; end if; end; end Delete; ----------------- -- End_Of_File -- ----------------- function End_Of_File (File : AFCB_Ptr) return Boolean is begin Check_File_Open (File); if feof (File.Stream) /= 0 then return True; else Check_Read_Status (File); if ungetc (fgetc (File.Stream), File.Stream) = EOF then clearerr (File.Stream); return True; else return False; end if; end if; end End_Of_File; ------------------- -- Errno_Message -- ------------------- function Errno_Message (Name : String; Errno : Integer := OS_Lib.Errno) return String is begin return Name & ": " & OS_Lib.Errno_Message (Err => Errno); end Errno_Message; -------------- -- Finalize -- -------------- procedure Finalize (V : in out File_IO_Clean_Up_Type) is pragma Warnings (Off, V); Fptr1 : aliased AFCB_Ptr; Fptr2 : AFCB_Ptr; Discard : int; begin -- Take a lock to protect global Open_Files data structure SSL.Lock_Task.all; -- First close all open files (the slightly complex form of this loop is -- required because Close as a side effect nulls out its argument). Fptr1 := Open_Files; while Fptr1 /= null loop Fptr2 := Fptr1.Next; Close (Fptr1'Access); Fptr1 := Fptr2; end loop; -- Now unlink all temporary files. We do not bother to free the blocks -- because we are just about to terminate the program. We also ignore -- any errors while attempting these unlink operations. while Temp_Files /= null loop Discard := unlink (Temp_Files.Name'Address); Temp_Files := Temp_Files.Next; end loop; SSL.Unlock_Task.all; exception when others => SSL.Unlock_Task.all; raise; end Finalize; ----------- -- Flush -- ----------- procedure Flush (File : AFCB_Ptr) is begin Check_Write_Status (File); if fflush (File.Stream) /= 0 then Raise_Device_Error (File); end if; end Flush; ---------------- -- Fopen_Mode -- ---------------- -- The fopen mode to be used is shown by the following table: -- OPEN CREATE -- Append_File "r+" "w+" -- In_File "r" "w+" -- Out_File (Direct_IO, Stream_IO) "r+" "w" -- Out_File (others) "w" "w" -- Inout_File "r+" "w+" -- Note: we do not use "a" or "a+" for Append_File, since this would not -- work in the case of stream files, where even if in append file mode, -- you can reset to earlier points in the file. The caller must use the -- Append_Set routine to deal with the necessary positioning. -- Note: in several cases, the fopen mode used allows reading and writing, -- but the setting of the Ada mode is more restrictive. For instance, -- Create in In_File mode uses "w+" which allows writing, but the Ada mode -- In_File will cause any write operations to be rejected with Mode_Error -- in any case. -- Note: for the Out_File/Open cases for other than the Direct_IO case, an -- initial call will be made by the caller to first open the file in "r" -- mode to be sure that it exists. The real open, in "w" mode, will then -- destroy this file. This is peculiar, but that's what Ada semantics -- require and the ACATS tests insist on. -- If text file translation is required, then either "b" or "t" is appended -- to the mode, depending on the setting of Text. procedure Fopen_Mode (Mode : File_Mode; Text : Boolean; Creat : Boolean; Amethod : Character; Fopstr : out Fopen_String) is Fptr : Positive; begin case Mode is when In_File => if Creat then Fopstr (1) := 'w'; Fopstr (2) := '+'; Fptr := 3; else Fopstr (1) := 'r'; Fptr := 2; end if; when Out_File => if Amethod in 'D' | 'S' and then not Creat then Fopstr (1) := 'r'; Fopstr (2) := '+'; Fptr := 3; else Fopstr (1) := 'w'; Fptr := 2; end if; when Inout_File | Append_File => Fopstr (1) := (if Creat then 'w' else 'r'); Fopstr (2) := '+'; Fptr := 3; end case; -- If text_translation_required is true then we need to append either a -- "t" or "b" to the string to get the right mode. if text_translation_required then Fopstr (Fptr) := (if Text then 't' else 'b'); Fptr := Fptr + 1; end if; Fopstr (Fptr) := ASCII.NUL; end Fopen_Mode; ---------- -- Form -- ---------- function Form (File : AFCB_Ptr) return String is begin if File = null then raise Status_Error with "Form: file not open"; else return File.Form.all (1 .. File.Form'Length - 1); end if; end Form; ------------------ -- Form_Boolean -- ------------------ function Form_Boolean (Form : String; Keyword : String; Default : Boolean) return Boolean is V1, V2 : Natural; pragma Unreferenced (V2); begin Form_Parameter (Form, Keyword, V1, V2); if V1 = 0 then return Default; elsif Form (V1) = 'y' then return True; elsif Form (V1) = 'n' then return False; else raise Use_Error with "invalid Form"; end if; end Form_Boolean; ------------------ -- Form_Integer -- ------------------ function Form_Integer (Form : String; Keyword : String; Default : Integer) return Integer is V1, V2 : Natural; V : Integer; begin Form_Parameter (Form, Keyword, V1, V2); if V1 = 0 then return Default; else V := 0; for J in V1 .. V2 loop if Form (J) not in '0' .. '9' then raise Use_Error with "invalid Form"; else V := V * 10 + Character'Pos (Form (J)) - Character'Pos ('0'); end if; if V > 999_999 then raise Use_Error with "invalid Form"; end if; end loop; return V; end if; end Form_Integer; -------------------- -- Form_Parameter -- -------------------- procedure Form_Parameter (Form : String; Keyword : String; Start : out Natural; Stop : out Natural) is Klen : constant Integer := Keyword'Length; begin for J in Form'First + Klen .. Form'Last - 1 loop if Form (J) = '=' and then Form (J - Klen .. J - 1) = Keyword then Start := J + 1; Stop := Start - 1; while Form (Stop + 1) /= ASCII.NUL and then Form (Stop + 1) /= ',' loop Stop := Stop + 1; end loop; return; end if; end loop; Start := 0; Stop := 0; end Form_Parameter; ------------- -- Is_Open -- ------------- function Is_Open (File : AFCB_Ptr) return Boolean is begin -- We return True if the file is open, and the underlying file stream is -- usable. In particular on Windows an application linked with -mwindows -- option set does not have a console attached. In this case standard -- files (Current_Output, Current_Error, Current_Input) are not created. -- We want Is_Open (Current_Output) to return False in this case. return File /= null and then fileno (File.Stream) /= -1; end Is_Open; ------------------- -- Make_Buffered -- ------------------- procedure Make_Buffered (File : AFCB_Ptr; Buf_Siz : Interfaces.C_Streams.size_t) is status : Integer; pragma Unreferenced (status); begin status := setvbuf (File.Stream, Null_Address, IOFBF, Buf_Siz); end Make_Buffered; ------------------------ -- Make_Line_Buffered -- ------------------------ procedure Make_Line_Buffered (File : AFCB_Ptr; Line_Siz : Interfaces.C_Streams.size_t) is status : Integer; pragma Unreferenced (status); begin status := setvbuf (File.Stream, Null_Address, IOLBF, Line_Siz); -- No error checking??? end Make_Line_Buffered; --------------------- -- Make_Unbuffered -- --------------------- procedure Make_Unbuffered (File : AFCB_Ptr) is status : Integer; pragma Unreferenced (status); begin status := setvbuf (File.Stream, Null_Address, IONBF, 0); -- No error checking??? end Make_Unbuffered; ---------- -- Mode -- ---------- function Mode (File : AFCB_Ptr) return File_Mode is begin if File = null then raise Status_Error with "Mode: file not open"; else return File.Mode; end if; end Mode; ---------- -- Name -- ---------- function Name (File : AFCB_Ptr) return String is begin if File = null then raise Status_Error with "Name: file not open"; else return File.Name.all (1 .. File.Name'Length - 1); end if; end Name; ---------- -- Open -- ---------- procedure Open (File_Ptr : in out AFCB_Ptr; Dummy_FCB : AFCB'Class; Mode : File_Mode; Name : String; Form : String; Amethod : Character; Creat : Boolean; Text : Boolean; C_Stream : FILEs := NULL_Stream) is pragma Warnings (Off, Dummy_FCB); -- Yes we know this is never assigned a value. That's intended, since -- all we ever use of this value is the tag for dispatching purposes. procedure Tmp_Name (Buffer : Address); pragma Import (C, Tmp_Name, "__gnat_tmp_name"); -- Set buffer (a String address) with a temporary filename function Get_Case_Sensitive return Integer; pragma Import (C, Get_Case_Sensitive, "__gnat_get_file_names_case_sensitive"); procedure Record_AFCB; -- Create and record new AFCB into the runtime, note that the -- implementation uses the variables below which corresponds to the -- status of the opened file. File_Names_Case_Sensitive : constant Boolean := Get_Case_Sensitive /= 0; -- Set to indicate whether the operating system convention is for file -- names to be case sensitive (e.g., in Unix, set True), or not case -- sensitive (e.g., in Windows, set False). Declared locally to avoid -- breaking the Preelaborate rule that disallows function calls at the -- library level. Stream : FILEs := C_Stream; -- Stream which we open in response to this request Shared : Shared_Status_Type; -- Setting of Shared_Status field for file Fopstr : aliased Fopen_String; -- Mode string used in fopen call Formstr : aliased String (1 .. Form'Length + 1); -- Form string with ASCII.NUL appended, folded to lower case Text_Encoding : Content_Encoding; Tempfile : constant Boolean := (Name'Length = 0); -- Indicates temporary file case Namelen : constant Integer := max_path_len; -- Length required for file name, not including final ASCII.NUL. -- Note that we used to reference L_tmpnam here, which is not reliable -- since __gnat_tmp_name does not always use tmpnam. Namestr : aliased String (1 .. Namelen + 1); -- Name as given or temporary file name with ASCII.NUL appended Fullname : aliased String (1 .. max_path_len + 1); -- Full name (as required for Name function, and as stored in the -- control block in the Name field) with ASCII.NUL appended. Full_Name_Len : Integer; -- Length of name actually stored in Fullname Encoding : CRTL.Filename_Encoding; -- Filename encoding specified into the form parameter ----------------- -- Record_AFCB -- ----------------- procedure Record_AFCB is begin File_Ptr := AFCB_Allocate (Dummy_FCB); -- Note that we cannot use an aggregate here as File_Ptr is a -- class-wide access to a limited type (Root_Stream_Type). File_Ptr.Is_Regular_File := is_regular_file (fileno (Stream)) /= 0; File_Ptr.Is_System_File := False; File_Ptr.Text_Encoding := Text_Encoding; File_Ptr.Shared_Status := Shared; File_Ptr.Access_Method := Amethod; File_Ptr.Stream := Stream; File_Ptr.Form := new String'(Formstr); File_Ptr.Name := new String'(Fullname (1 .. Full_Name_Len)); File_Ptr.Mode := Mode; File_Ptr.Is_Temporary_File := Tempfile; File_Ptr.Encoding := Encoding; Chain_File (File_Ptr); Append_Set (File_Ptr); end Record_AFCB; -- Start of processing for Open begin if File_Ptr /= null then raise Status_Error with "file already open"; end if; -- Acquire form string, setting required NUL terminator Formstr (1 .. Form'Length) := Form; Formstr (Formstr'Last) := ASCII.NUL; -- Convert form string to lower case for J in Formstr'Range loop if Formstr (J) in 'A' .. 'Z' then Formstr (J) := Character'Val (Character'Pos (Formstr (J)) + 32); end if; end loop; -- Acquire setting of shared parameter declare V1, V2 : Natural; begin Form_Parameter (Formstr, "shared", V1, V2); if V1 = 0 then Shared := None; elsif Formstr (V1 .. V2) = "yes" then Shared := Yes; elsif Formstr (V1 .. V2) = "no" then Shared := No; else raise Use_Error with "invalid Form"; end if; end; -- Acquire setting of encoding parameter declare V1, V2 : Natural; begin Form_Parameter (Formstr, "encoding", V1, V2); if V1 = 0 then Encoding := CRTL.Unspecified; elsif Formstr (V1 .. V2) = "utf8" then Encoding := CRTL.UTF8; elsif Formstr (V1 .. V2) = "8bits" then Encoding := CRTL.ASCII_8bits; else raise Use_Error with "invalid Form"; end if; end; -- Acquire setting of text_translation parameter. Only needed if this is -- a [Wide_[Wide_]]Text_IO file, in which case we default to True, but -- if the Form says Text_Translation=No, we use binary mode, so new-line -- will be just LF, even on Windows. if Text then Text_Encoding := Default_Text; else Text_Encoding := None; end if; if Text_Encoding in Text_Content_Encoding then declare V1, V2 : Natural; begin Form_Parameter (Formstr, "text_translation", V1, V2); if V1 = 0 then null; elsif Formstr (V1 .. V2) = "no" then Text_Encoding := None; elsif Formstr (V1 .. V2) = "text" or else Formstr (V1 .. V2) = "yes" then Text_Encoding := Interfaces.C_Streams.Text; elsif Formstr (V1 .. V2) = "wtext" then Text_Encoding := Wtext; elsif Formstr (V1 .. V2) = "u8text" then Text_Encoding := U8text; elsif Formstr (V1 .. V2) = "u16text" then Text_Encoding := U16text; else raise Use_Error with "invalid Form"; end if; end; end if; -- If we were given a stream (call from xxx.C_Streams.Open), then set -- the full name to the given one, and skip to end of processing. if Stream /= NULL_Stream then Full_Name_Len := Name'Length + 1; Fullname (1 .. Full_Name_Len - 1) := Name; Fullname (Full_Name_Len) := ASCII.NUL; -- Normal case of Open or Create else -- If temporary file case, get temporary file name and add to the -- list of temporary files to be deleted on exit. if Tempfile then if not Creat then raise Name_Error with "opening temp file without creating it"; end if; Tmp_Name (Namestr'Address); if Namestr (1) = ASCII.NUL then raise Use_Error with "invalid temp file name"; end if; -- Chain to temp file list, ensuring thread safety with a lock begin SSL.Lock_Task.all; Temp_Files := new Temp_File_Record'(Name => Namestr, Next => Temp_Files); SSL.Unlock_Task.all; exception when others => SSL.Unlock_Task.all; raise; end; -- Normal case of non-null name given else if Name'Length > Namelen then raise Name_Error with "file name too long"; end if; Namestr (1 .. Name'Length) := Name; Namestr (Name'Length + 1) := ASCII.NUL; end if; -- Get full name in accordance with the advice of RM A.8.2(22) full_name (Namestr'Address, Fullname'Address); if Fullname (1) = ASCII.NUL then raise Use_Error with Errno_Message (Name); end if; Full_Name_Len := 1; while Full_Name_Len < Fullname'Last and then Fullname (Full_Name_Len) /= ASCII.NUL loop Full_Name_Len := Full_Name_Len + 1; end loop; -- Fullname is generated by calling system's full_name. The problem -- is, full_name does nothing about the casing, so a file name -- comparison may generally speaking not be valid on non-case- -- sensitive systems, and in particular we get unexpected failures -- on Windows/Vista because of this. So we use s-casuti to force -- the name to lower case. if not File_Names_Case_Sensitive then To_Lower (Fullname (1 .. Full_Name_Len)); end if; -- If Shared=None or Shared=Yes, then check for the existence of -- another file with exactly the same full name. if Shared /= No then declare P : AFCB_Ptr; begin -- Take a task lock to protect Open_Files SSL.Lock_Task.all; -- Search list of open files P := Open_Files; while P /= null loop if Fullname (1 .. Full_Name_Len) = P.Name.all then -- If we get a match, and either file has Shared=None, -- then raise Use_Error, since we don't allow two files -- of the same name to be opened unless they specify the -- required sharing mode. if Shared = None or else P.Shared_Status = None then raise Use_Error with "reopening shared file"; -- If both files have Shared=Yes, then we acquire the -- stream from the located file to use as our stream. elsif Shared = Yes and then P.Shared_Status = Yes then Stream := P.Stream; Record_AFCB; exit; -- Otherwise one of the files has Shared=Yes and one has -- Shared=No. If the current file has Shared=No then all -- is well but we don't want to share any other file's -- stream. If the current file has Shared=Yes, we would -- like to share a stream, but not from a file that has -- Shared=No, so either way, we just continue the search. else null; end if; end if; P := P.Next; end loop; SSL.Unlock_Task.all; exception when others => SSL.Unlock_Task.all; raise; end; end if; -- Open specified file if we did not find an existing stream, -- otherwise we just return as there is nothing more to be done. if Stream /= NULL_Stream then return; else Fopen_Mode (Mode, Text_Encoding in Text_Content_Encoding, Creat, Amethod, Fopstr); -- A special case, if we are opening (OPEN case) a file and the -- mode returned by Fopen_Mode is not "r" or "r+", then we first -- make sure that the file exists as required by Ada semantics. if not Creat and then Fopstr (1) /= 'r' then if file_exists (Namestr'Address) = 0 then raise Name_Error with Errno_Message (Name); end if; end if; -- Now open the file. Note that we use the name as given in the -- original Open call for this purpose, since that seems the -- clearest implementation of the intent. It would presumably -- work to use the full name here, but if there is any difference, -- then we should use the name used in the call. -- Note: for a corresponding delete, we will use the full name, -- since by the time of the delete, the current working directory -- may have changed and we do not want to delete a different file. Stream := fopen (Namestr'Address, Fopstr'Address, Encoding); if Stream = NULL_Stream then -- Raise Name_Error if trying to open a non-existent file. -- Otherwise raise Use_Error. -- Should we raise Device_Error for ENOSPC??? declare function Is_File_Not_Found_Error (Errno_Value : Integer) return Integer; pragma Import (C, Is_File_Not_Found_Error, "__gnat_is_file_not_found_error"); -- Non-zero when the given errno value indicates a non- -- existing file. Errno : constant Integer := OS_Lib.Errno; Message : constant String := Errno_Message (Name, Errno); begin if Is_File_Not_Found_Error (Errno) /= 0 then raise Name_Error with Message; else raise Use_Error with Message; end if; end; end if; end if; end if; -- Stream has been successfully located or opened, so now we are -- committed to completing the opening of the file. Allocate block on -- heap and fill in its fields. Record_AFCB; end Open; ------------------------ -- Raise_Device_Error -- ------------------------ procedure Raise_Device_Error (File : AFCB_Ptr; Errno : Integer := OS_Lib.Errno) is begin -- Clear error status so that the same error is not reported twice if File /= null then clearerr (File.Stream); end if; raise Device_Error with OS_Lib.Errno_Message (Err => Errno); end Raise_Device_Error; -------------- -- Read_Buf -- -------------- procedure Read_Buf (File : AFCB_Ptr; Buf : Address; Siz : size_t) is Nread : size_t; begin Nread := fread (Buf, 1, Siz, File.Stream); if Nread = Siz then return; elsif ferror (File.Stream) /= 0 then Raise_Device_Error (File); elsif Nread = 0 then raise End_Error; else -- 0 < Nread < Siz raise Data_Error with "not enough data read"; end if; end Read_Buf; procedure Read_Buf (File : AFCB_Ptr; Buf : Address; Siz : Interfaces.C_Streams.size_t; Count : out Interfaces.C_Streams.size_t) is begin Count := fread (Buf, 1, Siz, File.Stream); if Count = 0 and then ferror (File.Stream) /= 0 then Raise_Device_Error (File); end if; end Read_Buf; ----------- -- Reset -- ----------- -- The reset which does not change the mode simply does a rewind procedure Reset (File_Ptr : access AFCB_Ptr) is File : AFCB_Ptr renames File_Ptr.all; begin Check_File_Open (File); Reset (File_Ptr, File.Mode); end Reset; -- The reset with a change in mode is done using freopen, and is not -- permitted except for regular files (since otherwise there is no name for -- the freopen, and in any case it seems meaningless). procedure Reset (File_Ptr : access AFCB_Ptr; Mode : File_Mode) is File : AFCB_Ptr renames File_Ptr.all; Fopstr : aliased Fopen_String; begin Check_File_Open (File); -- Change of mode not allowed for shared file or file with no name or -- file that is not a regular file, or for a system file. Note that we -- allow the "change" of mode if it is not in fact doing a change. if Mode /= File.Mode then if File.Shared_Status = Yes then raise Use_Error with "cannot change mode of shared file"; elsif File.Name'Length <= 1 then raise Use_Error with "cannot change mode of temp file"; elsif File.Is_System_File then raise Use_Error with "cannot change mode of system file"; elsif not File.Is_Regular_File then raise Use_Error with "cannot change mode of non-regular file"; end if; end if; -- For In_File or Inout_File for a regular file, we can just do a rewind -- if the mode is unchanged, which is more efficient than doing a full -- reopen. if Mode = File.Mode and then Mode in Read_File_Mode then rewind (File.Stream); -- Here the change of mode is permitted, we do it by reopening the file -- in the new mode and replacing the stream with a new stream. else Fopen_Mode (Mode, File.Text_Encoding in Text_Content_Encoding, False, File.Access_Method, Fopstr); File.Stream := freopen (File.Name.all'Address, Fopstr'Address, File.Stream, File.Encoding); if File.Stream = NULL_Stream then Close (File_Ptr); raise Use_Error; else File.Mode := Mode; Append_Set (File); end if; end if; end Reset; --------------- -- Write_Buf -- --------------- procedure Write_Buf (File : AFCB_Ptr; Buf : Address; Siz : size_t) is begin -- Note: for most purposes, the Siz and 1 parameters in the fwrite call -- could be reversed, but we have encountered systems where this is a -- better choice, since for some file formats, reversing the parameters -- results in records of one byte each. SSL.Abort_Defer.all; if fwrite (Buf, Siz, 1, File.Stream) /= 1 then if Siz /= 0 then SSL.Abort_Undefer.all; Raise_Device_Error (File); end if; end if; SSL.Abort_Undefer.all; end Write_Buf; end System.File_IO;