1------------------------------------------------------------------------------ 2-- -- 3-- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS -- 4-- -- 5-- S Y S T E M . I N T E R R U P T _ M A N A G E M E N T -- 6-- -- 7-- B o d y -- 8-- -- 9-- Copyright (C) 1992-2009, 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 POSIX threads version of this package 33 34-- Make a careful study of all signals available under the OS, to see which 35-- need to be reserved, kept always unmasked, or kept always unmasked. Be on 36-- the lookout for special signals that may be used by the thread library. 37 38-- Since this is a multi target file, the signal <-> exception mapping 39-- is simple minded. If you need a more precise and target specific 40-- signal handling, create a new s-intman.adb that will fit your needs. 41 42-- This file assumes that: 43 44-- SIGFPE, SIGILL, SIGSEGV and SIGBUS exist. They are mapped as follows: 45-- SIGPFE => Constraint_Error 46-- SIGILL => Program_Error 47-- SIGSEGV => Storage_Error 48-- SIGBUS => Storage_Error 49 50-- SIGINT exists and will be kept unmasked unless the pragma 51-- Unreserve_All_Interrupts is specified anywhere in the application. 52 53-- System.OS_Interface contains the following: 54-- SIGADAABORT: the signal that will be used to abort tasks. 55-- Unmasked: the OS specific set of signals that should be unmasked in 56-- all the threads. SIGADAABORT is unmasked by 57-- default 58-- Reserved: the OS specific set of signals that are reserved. 59 60with System.Task_Primitives; 61 62package body System.Interrupt_Management is 63 64 use Interfaces.C; 65 use System.OS_Interface; 66 67 type Interrupt_List is array (Interrupt_ID range <>) of Interrupt_ID; 68 Exception_Interrupts : constant Interrupt_List := 69 (SIGFPE, SIGILL, SIGSEGV, SIGBUS); 70 71 Unreserve_All_Interrupts : Interfaces.C.int; 72 pragma Import 73 (C, Unreserve_All_Interrupts, "__gl_unreserve_all_interrupts"); 74 75 ----------------------- 76 -- Local Subprograms -- 77 ----------------------- 78 79 function State (Int : Interrupt_ID) return Character; 80 pragma Import (C, State, "__gnat_get_interrupt_state"); 81 -- Get interrupt state. Defined in init.c The input argument is the 82 -- interrupt number, and the result is one of the following: 83 84 User : constant Character := 'u'; 85 Runtime : constant Character := 'r'; 86 Default : constant Character := 's'; 87 -- 'n' this interrupt not set by any Interrupt_State pragma 88 -- 'u' Interrupt_State pragma set state to User 89 -- 'r' Interrupt_State pragma set state to Runtime 90 -- 's' Interrupt_State pragma set state to System (use "default" 91 -- system handler) 92 93 procedure Notify_Exception 94 (signo : Signal; 95 siginfo : System.Address; 96 ucontext : System.Address); 97 -- This function identifies the Ada exception to be raised using the 98 -- information when the system received a synchronous signal. Since this 99 -- function is machine and OS dependent, different code has to be provided 100 -- for different target. 101 102 ---------------------- 103 -- Notify_Exception -- 104 ---------------------- 105 106 Signal_Mask : aliased sigset_t; 107 -- The set of signals handled by Notify_Exception 108 109 procedure Notify_Exception 110 (signo : Signal; 111 siginfo : System.Address; 112 ucontext : System.Address) 113 is 114 pragma Unreferenced (siginfo); 115 116 Result : Interfaces.C.int; 117 118 begin 119 -- With the __builtin_longjmp, the signal mask is not restored, so we 120 -- need to restore it explicitly. 121 122 Result := pthread_sigmask (SIG_UNBLOCK, Signal_Mask'Access, null); 123 pragma Assert (Result = 0); 124 125 -- Perform the necessary context adjustments prior to a raise 126 -- from a signal handler. 127 128 Adjust_Context_For_Raise (signo, ucontext); 129 130 -- Check that treatment of exception propagation here is consistent with 131 -- treatment of the abort signal in System.Task_Primitives.Operations. 132 133 case signo is 134 when SIGFPE => 135 raise Constraint_Error; 136 when SIGILL => 137 raise Program_Error; 138 when SIGSEGV => 139 raise Storage_Error; 140 when SIGBUS => 141 raise Storage_Error; 142 when others => 143 null; 144 end case; 145 end Notify_Exception; 146 147 ---------------- 148 -- Initialize -- 149 ---------------- 150 151 Initialized : Boolean := False; 152 153 procedure Initialize is 154 act : aliased struct_sigaction; 155 old_act : aliased struct_sigaction; 156 Result : System.OS_Interface.int; 157 158 Use_Alternate_Stack : constant Boolean := 159 System.Task_Primitives.Alternate_Stack_Size /= 0; 160 -- Whether to use an alternate signal stack for stack overflows 161 162 begin 163 if Initialized then 164 return; 165 end if; 166 167 Initialized := True; 168 169 -- Need to call pthread_init very early because it is doing signal 170 -- initializations. 171 172 pthread_init; 173 174 Abort_Task_Interrupt := SIGADAABORT; 175 176 act.sa_handler := Notify_Exception'Address; 177 178 -- Setting SA_SIGINFO asks the kernel to pass more than just the signal 179 -- number argument to the handler when it is called. The set of extra 180 -- parameters includes a pointer to the interrupted context, which the 181 -- ZCX propagation scheme needs. 182 183 -- Most man pages for sigaction mention that sa_sigaction should be set 184 -- instead of sa_handler when SA_SIGINFO is on. In practice, the two 185 -- fields are actually union'ed and located at the same offset. 186 187 -- On some targets, we set sa_flags to SA_NODEFER so that during the 188 -- handler execution we do not change the Signal_Mask to be masked for 189 -- the Signal. 190 191 -- This is a temporary fix to the problem that the Signal_Mask is not 192 -- restored after the exception (longjmp) from the handler. The right 193 -- fix should be made in sigsetjmp so that we save the Signal_Set and 194 -- restore it after a longjmp. 195 196 -- Since SA_NODEFER is obsolete, instead we reset explicitly the mask 197 -- in the exception handler. 198 199 Result := sigemptyset (Signal_Mask'Access); 200 pragma Assert (Result = 0); 201 202 -- Add signals that map to Ada exceptions to the mask 203 204 for J in Exception_Interrupts'Range loop 205 if State (Exception_Interrupts (J)) /= Default then 206 Result := 207 sigaddset (Signal_Mask'Access, Signal (Exception_Interrupts (J))); 208 pragma Assert (Result = 0); 209 end if; 210 end loop; 211 212 act.sa_mask := Signal_Mask; 213 214 pragma Assert (Keep_Unmasked = (Interrupt_ID'Range => False)); 215 pragma Assert (Reserve = (Interrupt_ID'Range => False)); 216 217 -- Process state of exception signals 218 219 for J in Exception_Interrupts'Range loop 220 if State (Exception_Interrupts (J)) /= User then 221 Keep_Unmasked (Exception_Interrupts (J)) := True; 222 Reserve (Exception_Interrupts (J)) := True; 223 224 if State (Exception_Interrupts (J)) /= Default then 225 act.sa_flags := SA_SIGINFO; 226 227 if Use_Alternate_Stack 228 and then Exception_Interrupts (J) = SIGSEGV 229 then 230 act.sa_flags := act.sa_flags + SA_ONSTACK; 231 end if; 232 233 Result := 234 sigaction 235 (Signal (Exception_Interrupts (J)), act'Unchecked_Access, 236 old_act'Unchecked_Access); 237 pragma Assert (Result = 0); 238 end if; 239 end if; 240 end loop; 241 242 if State (Abort_Task_Interrupt) /= User then 243 Keep_Unmasked (Abort_Task_Interrupt) := True; 244 Reserve (Abort_Task_Interrupt) := True; 245 end if; 246 247 -- Set SIGINT to unmasked state as long as it is not in "User" state. 248 -- Check for Unreserve_All_Interrupts last. 249 250 if State (SIGINT) /= User then 251 Keep_Unmasked (SIGINT) := True; 252 Reserve (SIGINT) := True; 253 end if; 254 255 -- Check all signals for state that requires keeping them unmasked and 256 -- reserved. 257 258 for J in Interrupt_ID'Range loop 259 if State (J) = Default or else State (J) = Runtime then 260 Keep_Unmasked (J) := True; 261 Reserve (J) := True; 262 end if; 263 end loop; 264 265 -- Add the set of signals that must always be unmasked for this target 266 267 for J in Unmasked'Range loop 268 Keep_Unmasked (Interrupt_ID (Unmasked (J))) := True; 269 Reserve (Interrupt_ID (Unmasked (J))) := True; 270 end loop; 271 272 -- Add target-specific reserved signals 273 274 for J in Reserved'Range loop 275 Reserve (Interrupt_ID (Reserved (J))) := True; 276 end loop; 277 278 -- Process pragma Unreserve_All_Interrupts. This overrides any settings 279 -- due to pragma Interrupt_State: 280 281 if Unreserve_All_Interrupts /= 0 then 282 Keep_Unmasked (SIGINT) := False; 283 Reserve (SIGINT) := False; 284 end if; 285 286 -- We do not really have Signal 0. We just use this value to identify 287 -- non-existent signals (see s-intnam.ads). Therefore, Signal should not 288 -- be used in all signal related operations hence mark it as reserved. 289 290 Reserve (0) := True; 291 end Initialize; 292 293end System.Interrupt_Management; 294