1------------------------------------------------------------------------------
2--                                                                          --
3--                 GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS                 --
4--                                                                          --
5--                  S Y S T E M . O S _ P R I M I T I V E S                 --
6--                                                                          --
7--                                  B o d y                                 --
8--                                                                          --
9--          Copyright (C) 1998-2014, Free Software Foundation, Inc.         --
10--                                                                          --
11-- GNARL 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-- GNARL was developed by the GNARL team at Florida State University.       --
28-- Extensive contributions were provided by Ada Core Technologies, Inc.     --
29--                                                                          --
30------------------------------------------------------------------------------
31
32--  This version is for POSIX-like operating systems
33
34package body System.OS_Primitives is
35
36   --  ??? These definitions are duplicated from System.OS_Interface
37   --  because we don't want to depend on any package. Consider removing
38   --  these declarations in System.OS_Interface and move these ones in
39   --  the spec.
40
41   type time_t is new Long_Integer;
42
43   type timespec is record
44      tv_sec  : time_t;
45      tv_nsec : Long_Integer;
46   end record;
47   pragma Convention (C, timespec);
48
49   function nanosleep (rqtp, rmtp : not null access timespec) return Integer;
50   pragma Import (C, nanosleep, "nanosleep");
51
52   -----------
53   -- Clock --
54   -----------
55
56   function Clock return Duration is
57
58      type timeval is array (1 .. 3) of Long_Integer;
59      --  The timeval array is sized to contain Long_Long_Integer sec and
60      --  Long_Integer usec. If Long_Long_Integer'Size = Long_Integer'Size then
61      --  it will be overly large but that will not effect the implementation
62      --  since it is not accessed directly.
63
64      procedure timeval_to_duration
65        (T    : not null access timeval;
66         sec  : not null access Long_Long_Integer;
67         usec : not null access Long_Integer);
68      pragma Import (C, timeval_to_duration, "__gnat_timeval_to_duration");
69
70      Micro  : constant := 10**6;
71      sec    : aliased Long_Long_Integer;
72      usec   : aliased Long_Integer;
73      TV     : aliased timeval;
74      Result : Integer;
75      pragma Unreferenced (Result);
76
77      function gettimeofday
78        (Tv : access timeval;
79         Tz : System.Address := System.Null_Address) return Integer;
80      pragma Import (C, gettimeofday, "gettimeofday");
81
82   begin
83      --  The return codes for gettimeofday are as follows (from man pages):
84      --    EPERM  settimeofday is called by someone other than the superuser
85      --    EINVAL Timezone (or something else) is invalid
86      --    EFAULT One of tv or tz pointed outside accessible address space
87
88      --  None of these codes signal a potential clock skew, hence the return
89      --  value is never checked.
90
91      Result := gettimeofday (TV'Access, System.Null_Address);
92      timeval_to_duration (TV'Access, sec'Access, usec'Access);
93      return Duration (sec) + Duration (usec) / Micro;
94   end Clock;
95
96   ---------------------
97   -- Monotonic_Clock --
98   ---------------------
99
100   function Monotonic_Clock return Duration renames Clock;
101
102   -----------------
103   -- To_Timespec --
104   -----------------
105
106   function To_Timespec (D : Duration) return timespec;
107
108   function To_Timespec (D : Duration) return timespec is
109      S : time_t;
110      F : Duration;
111
112   begin
113      S := time_t (Long_Long_Integer (D));
114      F := D - Duration (S);
115
116      --  If F has negative value due to a round-up, adjust for positive F
117      --  value.
118
119      if F < 0.0 then
120         S := S - 1;
121         F := F + 1.0;
122      end if;
123
124      return
125        timespec'(tv_sec  => S,
126                  tv_nsec => Long_Integer (Long_Long_Integer (F * 10#1#E9)));
127   end To_Timespec;
128
129   -----------------
130   -- Timed_Delay --
131   -----------------
132
133   procedure Timed_Delay
134     (Time : Duration;
135      Mode : Integer)
136   is
137      Request    : aliased timespec;
138      Remaind    : aliased timespec;
139      Rel_Time   : Duration;
140      Abs_Time   : Duration;
141      Base_Time  : constant Duration := Clock;
142      Check_Time : Duration := Base_Time;
143
144      Result : Integer;
145      pragma Unreferenced (Result);
146
147   begin
148      if Mode = Relative then
149         Rel_Time := Time;
150         Abs_Time := Time + Check_Time;
151      else
152         Rel_Time := Time - Check_Time;
153         Abs_Time := Time;
154      end if;
155
156      if Rel_Time > 0.0 then
157         loop
158            Request := To_Timespec (Rel_Time);
159            Result := nanosleep (Request'Access, Remaind'Access);
160            Check_Time := Clock;
161
162            exit when Abs_Time <= Check_Time or else Check_Time < Base_Time;
163
164            Rel_Time := Abs_Time - Check_Time;
165         end loop;
166      end if;
167   end Timed_Delay;
168
169   ----------------
170   -- Initialize --
171   ----------------
172
173   procedure Initialize is
174   begin
175      null;
176   end Initialize;
177
178end System.OS_Primitives;
179