1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT COMPILER COMPONENTS                         --
4--                                                                          --
5--           G N A T . S E R I A L _ C O M M U N I C A T I O N S            --
6--                                                                          --
7--                                 B o d y                                  --
8--                                                                          --
9--                    Copyright (C) 2007-2013, 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 3,  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.                                     --
17--                                                                          --
18-- As a special exception under Section 7 of GPL version 3, you are granted --
19-- additional permissions described in the GCC Runtime Library Exception,   --
20-- version 3.1, as published by the Free Software Foundation.               --
21--                                                                          --
22-- You should have received a copy of the GNU General Public License and    --
23-- a copy of the GCC Runtime Library Exception along with this program;     --
24-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
25-- <http://www.gnu.org/licenses/>.                                          --
26--                                                                          --
27-- GNAT was originally developed  by the GNAT team at  New York University. --
28-- Extensive contributions were provided by Ada Core Technologies Inc.      --
29--                                                                          --
30------------------------------------------------------------------------------
31
32--  This is the GNU/Linux implementation of this package
33
34with Ada.Streams;                use Ada.Streams;
35with Ada;                        use Ada;
36with Ada.Unchecked_Deallocation;
37
38with System;               use System;
39with System.Communication; use System.Communication;
40with System.CRTL;          use System.CRTL;
41with System.OS_Constants;
42
43with GNAT.OS_Lib; use GNAT.OS_Lib;
44
45package body GNAT.Serial_Communications is
46
47   package OSC renames System.OS_Constants;
48
49   use type Interfaces.C.unsigned;
50
51   type Port_Data is new int;
52
53   subtype unsigned is Interfaces.C.unsigned;
54   subtype char is Interfaces.C.char;
55   subtype unsigned_char is Interfaces.C.unsigned_char;
56
57   function fcntl (fd : int; cmd : int; value : int) return int;
58   pragma Import (C, fcntl, "fcntl");
59
60   C_Data_Rate : constant array (Data_Rate) of unsigned :=
61                   (B1200   => OSC.B1200,
62                    B2400   => OSC.B2400,
63                    B4800   => OSC.B4800,
64                    B9600   => OSC.B9600,
65                    B19200  => OSC.B19200,
66                    B38400  => OSC.B38400,
67                    B57600  => OSC.B57600,
68                    B115200 => OSC.B115200);
69
70   C_Bits      : constant array (Data_Bits) of unsigned :=
71                   (CS7 => OSC.CS7, CS8 => OSC.CS8);
72
73   C_Stop_Bits : constant array (Stop_Bits_Number) of unsigned :=
74                   (One => 0, Two => OSC.CSTOPB);
75
76   C_Parity    : constant array (Parity_Check) of unsigned :=
77                   (None => 0,
78                    Odd  => OSC.PARENB or OSC.PARODD,
79                    Even => OSC.PARENB);
80
81   procedure Raise_Error (Message : String; Error : Integer := Errno);
82   pragma No_Return (Raise_Error);
83
84   ----------
85   -- Name --
86   ----------
87
88   function Name (Number : Positive) return Port_Name is
89      N     : constant Natural := Number - 1;
90      N_Img : constant String  := Natural'Image (N);
91   begin
92      return Port_Name ("/dev/ttyS" & N_Img (N_Img'First + 1 .. N_Img'Last));
93   end Name;
94
95   ----------
96   -- Open --
97   ----------
98
99   procedure Open
100     (Port : out Serial_Port;
101      Name : Port_Name)
102   is
103      use OSC;
104
105      C_Name : constant String := String (Name) & ASCII.NUL;
106      Res    : int;
107
108   begin
109      if Port.H = null then
110         Port.H := new Port_Data;
111      end if;
112
113      Port.H.all := Port_Data (open
114         (C_Name (C_Name'First)'Address, int (O_RDWR + O_NOCTTY + O_NDELAY)));
115
116      if Port.H.all = -1 then
117         Raise_Error ("open: open failed");
118      end if;
119
120      --  By default we are in blocking mode
121
122      Res := fcntl (int (Port.H.all), F_SETFL, 0);
123
124      if Res = -1 then
125         Raise_Error ("open: fcntl failed");
126      end if;
127   end Open;
128
129   -----------------
130   -- Raise_Error --
131   -----------------
132
133   procedure Raise_Error (Message : String; Error : Integer := Errno) is
134   begin
135      raise Serial_Error with Message
136        & (if Error /= 0
137           then " (" & Errno_Message (Err => Error) & ')'
138           else "");
139   end Raise_Error;
140
141   ----------
142   -- Read --
143   ----------
144
145   overriding procedure Read
146     (Port   : in out Serial_Port;
147      Buffer : out Stream_Element_Array;
148      Last   : out Stream_Element_Offset)
149   is
150      Len : constant size_t := Buffer'Length;
151      Res : ssize_t;
152
153   begin
154      if Port.H = null then
155         Raise_Error ("read: port not opened", 0);
156      end if;
157
158      Res := read (Integer (Port.H.all), Buffer'Address, Len);
159
160      if Res = -1 then
161         Raise_Error ("read failed");
162      end if;
163
164      Last := Last_Index (Buffer'First, size_t (Res));
165   end Read;
166
167   ---------
168   -- Set --
169   ---------
170
171   procedure Set
172     (Port      : Serial_Port;
173      Rate      : Data_Rate        := B9600;
174      Bits      : Data_Bits        := CS8;
175      Stop_Bits : Stop_Bits_Number := One;
176      Parity    : Parity_Check     := None;
177      Block     : Boolean          := True;
178      Local     : Boolean          := True;
179      Flow      : Flow_Control     := None;
180      Timeout   : Duration         := 10.0)
181   is
182      use OSC;
183
184      type termios is record
185         c_iflag  : unsigned;
186         c_oflag  : unsigned;
187         c_cflag  : unsigned;
188         c_lflag  : unsigned;
189         c_line   : unsigned_char;
190         c_cc     : Interfaces.C.char_array (0 .. 31);
191         c_ispeed : unsigned;
192         c_ospeed : unsigned;
193      end record;
194      pragma Convention (C, termios);
195
196      function tcgetattr (fd : int; termios_p : Address) return int;
197      pragma Import (C, tcgetattr, "tcgetattr");
198
199      function tcsetattr
200        (fd : int; action : int; termios_p : Address) return int;
201      pragma Import (C, tcsetattr, "tcsetattr");
202
203      function tcflush (fd : int; queue_selector : int) return int;
204      pragma Import (C, tcflush, "tcflush");
205
206      Current : termios;
207
208      Res : int;
209      pragma Warnings (Off, Res);
210      --  Warnings off, since we don't always test the result
211
212   begin
213      if Port.H = null then
214         Raise_Error ("set: port not opened", 0);
215      end if;
216
217      --  Get current port settings
218
219      Res := tcgetattr (int (Port.H.all), Current'Address);
220
221      --  Change settings now
222
223      Current.c_cflag := C_Data_Rate (Rate)
224                           or C_Bits (Bits)
225                           or C_Stop_Bits (Stop_Bits)
226                           or C_Parity (Parity)
227                           or CREAD;
228      Current.c_iflag := 0;
229      Current.c_lflag := 0;
230      Current.c_oflag := 0;
231
232      if Local then
233         Current.c_cflag := Current.c_cflag or CLOCAL;
234      end if;
235
236      case Flow is
237         when None     =>
238            null;
239         when RTS_CTS  =>
240            Current.c_cflag := Current.c_cflag or CRTSCTS;
241         when Xon_Xoff =>
242            Current.c_iflag := Current.c_iflag or IXON;
243      end case;
244
245      Current.c_ispeed     := Data_Rate_Value (Rate);
246      Current.c_ospeed     := Data_Rate_Value (Rate);
247      Current.c_cc (VMIN)  := char'Val (0);
248      Current.c_cc (VTIME) := char'Val (Natural (Timeout * 10));
249
250      --  Set port settings
251
252      Res := tcflush (int (Port.H.all), TCIFLUSH);
253      Res := tcsetattr (int (Port.H.all), TCSANOW, Current'Address);
254
255      --  Block
256
257      Res := fcntl (int (Port.H.all), F_SETFL, (if Block then 0 else FNDELAY));
258
259      if Res = -1 then
260         Raise_Error ("set: fcntl failed");
261      end if;
262   end Set;
263
264   -----------
265   -- Write --
266   -----------
267
268   overriding procedure Write
269     (Port   : in out Serial_Port;
270      Buffer : Stream_Element_Array)
271   is
272      Len : constant size_t := Buffer'Length;
273      Res : ssize_t;
274
275   begin
276      if Port.H = null then
277         Raise_Error ("write: port not opened", 0);
278      end if;
279
280      Res := write (int (Port.H.all), Buffer'Address, Len);
281
282      if Res = -1 then
283         Raise_Error ("write failed");
284      end if;
285
286      pragma Assert (size_t (Res) = Len);
287   end Write;
288
289   -----------
290   -- Close --
291   -----------
292
293   procedure Close (Port : in out Serial_Port) is
294      procedure Unchecked_Free is
295        new Unchecked_Deallocation (Port_Data, Port_Data_Access);
296
297      Res : int;
298      pragma Unreferenced (Res);
299
300   begin
301      if Port.H /= null then
302         Res := close (int (Port.H.all));
303         Unchecked_Free (Port.H);
304      end if;
305   end Close;
306
307end GNAT.Serial_Communications;
308