1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT RUN-TIME COMPONENTS                         --
4--                                                                          --
5--    A D A . E X C E P T I O N S . L A S T _ C H A N C E _ H A N D L E R   --
6--                                                                          --
7--                                 B o d y                                  --
8--                                                                          --
9--          Copyright (C) 2003-2009, Free Software Foundation, Inc.         --
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--  Default version for most targets
33
34pragma Warnings (Off);
35pragma Compiler_Unit;
36pragma Warnings (On);
37
38with System.Standard_Library; use System.Standard_Library;
39with System.Soft_Links;
40
41procedure Ada.Exceptions.Last_Chance_Handler
42  (Except : Exception_Occurrence)
43is
44   procedure Unhandled_Terminate;
45   pragma No_Return (Unhandled_Terminate);
46   pragma Import (C, Unhandled_Terminate, "__gnat_unhandled_terminate");
47   --  Perform system dependent shutdown code
48
49   function Exception_Message_Length
50     (X : Exception_Occurrence) return Natural;
51   pragma Import (Ada, Exception_Message_Length, "__gnat_exception_msg_len");
52
53   procedure Append_Info_Exception_Message
54     (X : Exception_Occurrence; Info : in out String; Ptr : in out Natural);
55   pragma Import
56     (Ada, Append_Info_Exception_Message, "__gnat_append_info_e_msg");
57
58   procedure Append_Info_Exception_Information
59     (X : Exception_Occurrence; Info : in out String; Ptr : in out Natural);
60   pragma Import
61     (Ada, Append_Info_Exception_Information, "__gnat_append_info_e_info");
62
63   procedure To_Stderr (S : String);
64   pragma Import (Ada, To_Stderr, "__gnat_to_stderr");
65   --  Little routine to output string to stderr
66
67   Ptr   : Natural := 0;
68   Nobuf : String (1 .. 0);
69
70   Nline : constant String := String'(1 => ASCII.LF);
71   --  Convenient shortcut
72
73begin
74   --  Do not execute any task termination code when shutting down the system.
75   --  The Adafinal procedure would execute the task termination routine for
76   --  normal termination, but we have already executed the task termination
77   --  procedure because of an unhandled exception.
78
79   System.Soft_Links.Task_Termination_Handler :=
80     System.Soft_Links.Task_Termination_NT'Access;
81
82   --  We shutdown the runtime now. The rest of the procedure needs to be
83   --  careful not to use anything that would require runtime support. In
84   --  particular, functions returning strings are banned since the sec stack
85   --  is no longer functional. This is particularly important to note for the
86   --  Exception_Information output. We used to allow the tailored version to
87   --  show up here, which turned out to be a bad idea as it might involve a
88   --  traceback decorator the length of which we don't control. Potentially
89   --  heavy primary/secondary stack use or dynamic allocations right before
90   --  this point are not welcome, moving the output before the finalization
91   --  raises order of outputs concerns, and decorators are intended to only
92   --  be used with exception traces, which should have been issued already.
93
94   System.Standard_Library.Adafinal;
95
96   --  Print a message only when exception traces are not active
97
98   if Exception_Trace /= RM_Convention then
99      null;
100
101   --  Check for special case of raising _ABORT_SIGNAL, which is not
102   --  really an exception at all. We recognize this by the fact that
103   --  it is the only exception whose name starts with underscore.
104
105   elsif To_Ptr (Except.Id.Full_Name) (1) = '_' then
106      To_Stderr (Nline);
107      To_Stderr ("Execution terminated by abort of environment task");
108      To_Stderr (Nline);
109
110   --  If no tracebacks, we print the unhandled exception in the old style
111   --  (i.e. the style used before ZCX was implemented). We do this to
112   --  retain compatibility.
113
114   elsif Except.Num_Tracebacks = 0 then
115      To_Stderr (Nline);
116      To_Stderr ("raised ");
117      To_Stderr
118        (To_Ptr (Except.Id.Full_Name) (1 .. Except.Id.Name_Length - 1));
119
120      if Exception_Message_Length (Except) /= 0 then
121         To_Stderr (" : ");
122         Append_Info_Exception_Message (Except, Nobuf, Ptr);
123      end if;
124
125      To_Stderr (Nline);
126
127   --  Traceback exists
128
129   else
130      To_Stderr (Nline);
131      To_Stderr ("Execution terminated by unhandled exception");
132      To_Stderr (Nline);
133
134      Append_Info_Exception_Information (Except, Nobuf, Ptr);
135   end if;
136
137   Unhandled_Terminate;
138end Ada.Exceptions.Last_Chance_Handler;
139