|
111
|
1 ------------------------------------------------------------------------------
|
|
|
2 -- --
|
|
|
3 -- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS --
|
|
|
4 -- --
|
|
|
5 -- S Y S T E M . S T A C K _ C H E C K I N G . O P E R A T I O N S --
|
|
|
6 -- --
|
|
|
7 -- B o d y --
|
|
|
8 -- --
|
|
|
9 -- Copyright (C) 1999-2017, 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 is the general implementation of this package. There is a VxWorks
|
|
|
33 -- specific version of this package (s-stchop-vxworks.adb). This file should
|
|
|
34 -- be kept synchronized with it.
|
|
|
35
|
|
|
36 pragma Restrictions (No_Elaboration_Code);
|
|
|
37 -- We want to guarantee the absence of elaboration code because the
|
|
|
38 -- binder does not handle references to this package.
|
|
|
39
|
|
|
40 with System.Storage_Elements; use System.Storage_Elements;
|
|
|
41 with System.Parameters; use System.Parameters;
|
|
|
42 with System.Soft_Links;
|
|
|
43 with System.CRTL;
|
|
|
44
|
|
|
45 package body System.Stack_Checking.Operations is
|
|
|
46
|
|
|
47 Kilobyte : constant := 1024;
|
|
|
48
|
|
|
49 function Set_Stack_Info
|
|
|
50 (Stack : not null access Stack_Access) return Stack_Access;
|
|
|
51 -- The function Set_Stack_Info is the actual function that updates the
|
|
|
52 -- cache containing a pointer to the Stack_Info. It may also be used for
|
|
|
53 -- detecting asynchronous abort in combination with Invalidate_Self_Cache.
|
|
|
54 --
|
|
|
55 -- Set_Stack_Info should do the following things in order:
|
|
|
56 -- 1) Get the Stack_Access value for the current task
|
|
|
57 -- 2) Set Stack.all to the value obtained in 1)
|
|
|
58 -- 3) Optionally Poll to check for asynchronous abort
|
|
|
59 --
|
|
|
60 -- This order is important because if at any time a write to the stack
|
|
|
61 -- cache is pending, that write should be followed by a Poll to prevent
|
|
|
62 -- losing signals.
|
|
|
63 --
|
|
|
64 -- Note: This function must be compiled with Polling turned off
|
|
|
65 --
|
|
|
66 -- Note: on systems with real thread-local storage, Set_Stack_Info should
|
|
|
67 -- return an access value for such local storage. In those cases the cache
|
|
|
68 -- will always be up-to-date.
|
|
|
69
|
|
|
70 ----------------------------
|
|
|
71 -- Invalidate_Stack_Cache --
|
|
|
72 ----------------------------
|
|
|
73
|
|
|
74 procedure Invalidate_Stack_Cache (Any_Stack : Stack_Access) is
|
|
|
75 pragma Warnings (Off, Any_Stack);
|
|
|
76 begin
|
|
|
77 Cache := Null_Stack;
|
|
|
78 end Invalidate_Stack_Cache;
|
|
|
79
|
|
|
80 -----------------------------
|
|
|
81 -- Notify_Stack_Attributes --
|
|
|
82 -----------------------------
|
|
|
83
|
|
|
84 procedure Notify_Stack_Attributes
|
|
|
85 (Initial_SP : System.Address;
|
|
|
86 Size : System.Storage_Elements.Storage_Offset)
|
|
|
87 is
|
|
|
88 My_Stack : constant Stack_Access := Soft_Links.Get_Stack_Info.all;
|
|
|
89
|
|
|
90 -- We piggyback on the 'Limit' field to store what will be used as the
|
|
|
91 -- 'Base' and leave the 'Size' alone to not interfere with the logic in
|
|
|
92 -- Set_Stack_Info below.
|
|
|
93
|
|
|
94 pragma Unreferenced (Size);
|
|
|
95
|
|
|
96 begin
|
|
|
97 My_Stack.Limit := Initial_SP;
|
|
|
98 end Notify_Stack_Attributes;
|
|
|
99
|
|
|
100 --------------------
|
|
|
101 -- Set_Stack_Info --
|
|
|
102 --------------------
|
|
|
103
|
|
|
104 function Set_Stack_Info
|
|
|
105 (Stack : not null access Stack_Access) return Stack_Access
|
|
|
106 is
|
|
|
107 type Frame_Mark is null record;
|
|
|
108 Frame_Location : Frame_Mark;
|
|
|
109 Frame_Address : constant Address := Frame_Location'Address;
|
|
|
110
|
|
|
111 My_Stack : Stack_Access;
|
|
|
112 Limit_Chars : System.Address;
|
|
|
113 Limit : Integer;
|
|
|
114
|
|
|
115 begin
|
|
|
116 -- The order of steps 1 .. 3 is important, see specification
|
|
|
117
|
|
|
118 -- 1) Get the Stack_Access value for the current task
|
|
|
119
|
|
|
120 My_Stack := Soft_Links.Get_Stack_Info.all;
|
|
|
121
|
|
|
122 if My_Stack.Base = Null_Address then
|
|
|
123
|
|
|
124 -- First invocation, initialize based on the assumption that there
|
|
|
125 -- are Environment_Stack_Size bytes available beyond the current
|
|
|
126 -- frame address.
|
|
|
127
|
|
|
128 if My_Stack.Size = 0 then
|
|
|
129 My_Stack.Size := Storage_Offset (Default_Env_Stack_Size);
|
|
|
130
|
|
|
131 -- When the environment variable GNAT_STACK_LIMIT is set, set
|
|
|
132 -- Environment_Stack_Size to that number of kB.
|
|
|
133
|
|
|
134 Limit_Chars := System.CRTL.getenv ("GNAT_STACK_LIMIT" & ASCII.NUL);
|
|
|
135
|
|
|
136 if Limit_Chars /= Null_Address then
|
|
|
137 Limit := System.CRTL.atoi (Limit_Chars);
|
|
|
138
|
|
|
139 if Limit >= 0 then
|
|
|
140 My_Stack.Size := Storage_Offset (Limit) * Kilobyte;
|
|
|
141 end if;
|
|
|
142 end if;
|
|
|
143 end if;
|
|
|
144
|
|
|
145 -- If a stack base address has been registered, honor it. Fallback to
|
|
|
146 -- the address of a local object otherwise.
|
|
|
147
|
|
|
148 My_Stack.Base :=
|
|
|
149 (if My_Stack.Limit /= System.Null_Address
|
|
|
150 then My_Stack.Limit else Frame_Address);
|
|
|
151
|
|
|
152 if Stack_Grows_Down then
|
|
|
153
|
|
|
154 -- Prevent wrap-around on too big stack sizes
|
|
|
155
|
|
|
156 My_Stack.Limit := My_Stack.Base - My_Stack.Size;
|
|
|
157
|
|
|
158 if My_Stack.Limit > My_Stack.Base then
|
|
|
159 My_Stack.Limit := Address'First;
|
|
|
160 end if;
|
|
|
161
|
|
|
162 else
|
|
|
163 My_Stack.Limit := My_Stack.Base + My_Stack.Size;
|
|
|
164
|
|
|
165 -- Prevent wrap-around on too big stack sizes
|
|
|
166
|
|
|
167 if My_Stack.Limit < My_Stack.Base then
|
|
|
168 My_Stack.Limit := Address'Last;
|
|
|
169 end if;
|
|
|
170 end if;
|
|
|
171 end if;
|
|
|
172
|
|
|
173 -- 2) Set Stack.all to the value obtained in 1)
|
|
|
174
|
|
|
175 Stack.all := My_Stack;
|
|
|
176
|
|
|
177 -- 3) Optionally Poll to check for asynchronous abort
|
|
|
178
|
|
|
179 if Soft_Links.Check_Abort_Status.all /= 0 then
|
|
|
180 raise Standard'Abort_Signal;
|
|
|
181 end if;
|
|
|
182
|
|
|
183 -- Never trust the cached value, but return local copy
|
|
|
184
|
|
|
185 return My_Stack;
|
|
|
186 end Set_Stack_Info;
|
|
|
187
|
|
|
188 -----------------
|
|
|
189 -- Stack_Check --
|
|
|
190 -----------------
|
|
|
191
|
|
|
192 function Stack_Check
|
|
|
193 (Stack_Address : System.Address) return Stack_Access
|
|
|
194 is
|
|
|
195 type Frame_Marker is null record;
|
|
|
196 Marker : Frame_Marker;
|
|
|
197 Cached_Stack : constant Stack_Access := Cache;
|
|
|
198 Frame_Address : constant System.Address := Marker'Address;
|
|
|
199
|
|
|
200 begin
|
|
|
201 -- The parameter may have wrapped around in System.Address arithmetics.
|
|
|
202 -- In that case, we have no other choices than raising the exception.
|
|
|
203
|
|
|
204 if (Stack_Grows_Down and then
|
|
|
205 Stack_Address > Frame_Address)
|
|
|
206 or else
|
|
|
207 (not Stack_Grows_Down and then
|
|
|
208 Stack_Address < Frame_Address)
|
|
|
209 then
|
|
|
210 raise Storage_Error with "stack overflow detected";
|
|
|
211 end if;
|
|
|
212
|
|
|
213 -- This function first does a "cheap" check which is correct if it
|
|
|
214 -- succeeds. In case of failure, the full check is done. Ideally the
|
|
|
215 -- cheap check should be done in an optimized manner, or be inlined.
|
|
|
216
|
|
|
217 if (Stack_Grows_Down and then
|
|
|
218 (Frame_Address <= Cached_Stack.Base
|
|
|
219 and then
|
|
|
220 Stack_Address > Cached_Stack.Limit))
|
|
|
221 or else
|
|
|
222 (not Stack_Grows_Down and then
|
|
|
223 (Frame_Address >= Cached_Stack.Base
|
|
|
224 and then
|
|
|
225 Stack_Address < Cached_Stack.Limit))
|
|
|
226 then
|
|
|
227 -- Cached_Stack is valid as it passed the stack check
|
|
|
228
|
|
|
229 return Cached_Stack;
|
|
|
230 end if;
|
|
|
231
|
|
|
232 Full_Check :
|
|
|
233 declare
|
|
|
234 My_Stack : constant Stack_Access := Set_Stack_Info (Cache'Access);
|
|
|
235 -- At this point Stack.all might already be invalid, so
|
|
|
236 -- it is essential to use our local copy of Stack.
|
|
|
237
|
|
|
238 begin
|
|
|
239 if (Stack_Grows_Down and then
|
|
|
240 (not (Frame_Address <= My_Stack.Base)))
|
|
|
241 or else
|
|
|
242 (not Stack_Grows_Down and then
|
|
|
243 (not (Frame_Address >= My_Stack.Base)))
|
|
|
244 then
|
|
|
245 -- The returned Base is lower than the stored one, so assume that
|
|
|
246 -- the original one wasn't right and use the current Frame_Address
|
|
|
247 -- as new one. This allows Base to be initialized with the
|
|
|
248 -- Frame_Address as approximation. During initialization the
|
|
|
249 -- Frame_Address will be close to the stack base anyway: the
|
|
|
250 -- difference should be compensated for in the stack reserve.
|
|
|
251
|
|
|
252 My_Stack.Base := Frame_Address;
|
|
|
253 end if;
|
|
|
254
|
|
|
255 if (Stack_Grows_Down
|
|
|
256 and then Stack_Address < My_Stack.Limit)
|
|
|
257 or else
|
|
|
258 (not Stack_Grows_Down
|
|
|
259 and then Stack_Address > My_Stack.Limit)
|
|
|
260 then
|
|
|
261 raise Storage_Error with "stack overflow detected";
|
|
|
262 end if;
|
|
|
263
|
|
|
264 return My_Stack;
|
|
|
265 end Full_Check;
|
|
|
266 end Stack_Check;
|
|
|
267
|
|
|
268 ------------------------
|
|
|
269 -- Update_Stack_Cache --
|
|
|
270 ------------------------
|
|
|
271
|
|
|
272 procedure Update_Stack_Cache (Stack : Stack_Access) is
|
|
|
273 begin
|
|
|
274 if not Multi_Processor then
|
|
|
275 Cache := Stack;
|
|
|
276 end if;
|
|
|
277 end Update_Stack_Cache;
|
|
|
278
|
|
|
279 end System.Stack_Checking.Operations;
|
