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) 1992-2019, 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 QNX/Neutrino 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 procedure Signal_Trampoline 80 (signo : Signal; 81 siginfo : System.Address; 82 ucontext : System.Address; 83 handler : System.Address); 84 pragma Import (C, Signal_Trampoline, "__gnat_sigtramp"); 85 -- Pass the real handler to a speical function that handles unwinding by 86 -- skipping over the kernel signal frame (which doesn't contain any unwind 87 -- information). 88 89 procedure Map_Signal 90 (signo : Signal; 91 siginfo : System.Address; 92 ucontext : System.Address); 93 pragma Import (C, Map_Signal, "__gnat_map_signal"); 94 95 function State (Int : Interrupt_ID) return Character; 96 pragma Import (C, State, "__gnat_get_interrupt_state"); 97 -- Get interrupt state. Defined in init.c The input argument is the 98 -- interrupt number, and the result is one of the following: 99 100 User : constant Character := 'u'; 101 Runtime : constant Character := 'r'; 102 Default : constant Character := 's'; 103 -- 'n' this interrupt not set by any Interrupt_State pragma 104 -- 'u' Interrupt_State pragma set state to User 105 -- 'r' Interrupt_State pragma set state to Runtime 106 -- 's' Interrupt_State pragma set state to System (use "default" 107 -- system handler) 108 109 procedure Notify_Exception 110 (signo : Signal; 111 siginfo : System.Address; 112 ucontext : System.Address); 113 -- This function identifies the Ada exception to be raised using the 114 -- information when the system received a synchronous signal. Since this 115 -- function is machine and OS dependent, different code has to be provided 116 -- for different target. 117 118 ---------------------- 119 -- Notify_Exception -- 120 ---------------------- 121 122 Signal_Mask : aliased sigset_t; 123 -- The set of signals handled by Notify_Exception 124 125 procedure Notify_Exception 126 (signo : Signal; 127 siginfo : System.Address; 128 ucontext : System.Address) 129 is 130 Result : Interfaces.C.int; 131 132 begin 133 -- With the __builtin_longjmp, the signal mask is not restored, so we 134 -- need to restore it explicitly. 135 136 Result := pthread_sigmask (SIG_UNBLOCK, Signal_Mask'Access, null); 137 pragma Assert (Result = 0); 138 139 -- Perform the necessary context adjustments prior to a raise 140 -- from a signal handler. 141 142 Adjust_Context_For_Raise (signo, ucontext); 143 144 -- Check that treatment of exception propagation here is consistent with 145 -- treatment of the abort signal in System.Task_Primitives.Operations. 146 147 Signal_Trampoline (signo, siginfo, ucontext, Map_Signal'Address); 148 end Notify_Exception; 149 150 ---------------- 151 -- Initialize -- 152 ---------------- 153 154 Initialized : Boolean := False; 155 156 procedure Initialize is 157 act : aliased struct_sigaction; 158 old_act : aliased struct_sigaction; 159 Result : System.OS_Interface.int; 160 161 Use_Alternate_Stack : constant Boolean := 162 System.Task_Primitives.Alternate_Stack_Size /= 0; 163 -- Whether to use an alternate signal stack for stack overflows 164 165 begin 166 if Initialized then 167 return; 168 end if; 169 170 Initialized := True; 171 172 -- Need to call pthread_init very early because it is doing signal 173 -- initializations. 174 175 pthread_init; 176 177 Abort_Task_Interrupt := SIGADAABORT; 178 179 act.sa_handler := Notify_Exception'Address; 180 181 -- Setting SA_SIGINFO asks the kernel to pass more than just the signal 182 -- number argument to the handler when it is called. The set of extra 183 -- parameters includes a pointer to the interrupted context, which the 184 -- ZCX propagation scheme needs. 185 186 -- Most man pages for sigaction mention that sa_sigaction should be set 187 -- instead of sa_handler when SA_SIGINFO is on. In practice, the two 188 -- fields are actually union'ed and located at the same offset. 189 190 -- On some targets, we set sa_flags to SA_NODEFER so that during the 191 -- handler execution we do not change the Signal_Mask to be masked for 192 -- the Signal. 193 194 -- This is a temporary fix to the problem that the Signal_Mask is not 195 -- restored after the exception (longjmp) from the handler. The right 196 -- fix should be made in sigsetjmp so that we save the Signal_Set and 197 -- restore it after a longjmp. 198 199 -- Since SA_NODEFER is obsolete, instead we reset explicitly the mask 200 -- in the exception handler. 201 202 Result := sigemptyset (Signal_Mask'Access); 203 pragma Assert (Result = 0); 204 205 -- Add signals that map to Ada exceptions to the mask 206 207 for J in Exception_Interrupts'Range loop 208 if State (Exception_Interrupts (J)) /= Default then 209 Result := 210 sigaddset (Signal_Mask'Access, Signal (Exception_Interrupts (J))); 211 pragma Assert (Result = 0); 212 end if; 213 end loop; 214 215 act.sa_mask := Signal_Mask; 216 217 pragma Assert (Keep_Unmasked = (Interrupt_ID'Range => False)); 218 pragma Assert (Reserve = (Interrupt_ID'Range => False)); 219 220 -- Process state of exception signals 221 222 for J in Exception_Interrupts'Range loop 223 if State (Exception_Interrupts (J)) /= User then 224 Keep_Unmasked (Exception_Interrupts (J)) := True; 225 Reserve (Exception_Interrupts (J)) := True; 226 227 if State (Exception_Interrupts (J)) /= Default then 228 act.sa_flags := SA_SIGINFO; 229 230 if Use_Alternate_Stack 231 and then Exception_Interrupts (J) = SIGSEGV 232 then 233 act.sa_flags := act.sa_flags + SA_ONSTACK; 234 end if; 235 236 Result := 237 sigaction 238 (Signal (Exception_Interrupts (J)), act'Unchecked_Access, 239 old_act'Unchecked_Access); 240 pragma Assert (Result = 0); 241 end if; 242 end if; 243 end loop; 244 245 if State (Abort_Task_Interrupt) /= User then 246 Keep_Unmasked (Abort_Task_Interrupt) := True; 247 Reserve (Abort_Task_Interrupt) := True; 248 end if; 249 250 -- Set SIGINT to unmasked state as long as it is not in "User" state. 251 -- Check for Unreserve_All_Interrupts last. 252 253 if State (SIGINT) /= User then 254 Keep_Unmasked (SIGINT) := True; 255 Reserve (SIGINT) := True; 256 end if; 257 258 -- Check all signals for state that requires keeping them unmasked and 259 -- reserved. 260 261 for J in Interrupt_ID'Range loop 262 if State (J) = Default or else State (J) = Runtime then 263 Keep_Unmasked (J) := True; 264 Reserve (J) := True; 265 end if; 266 end loop; 267 268 -- Add the set of signals that must always be unmasked for this target 269 270 for J in Unmasked'Range loop 271 Keep_Unmasked (Interrupt_ID (Unmasked (J))) := True; 272 Reserve (Interrupt_ID (Unmasked (J))) := True; 273 end loop; 274 275 -- Add target-specific reserved signals 276 277 if Reserved'Length > 0 then 278 for J in Reserved'Range loop 279 Reserve (Interrupt_ID (Reserved (J))) := True; 280 end loop; 281 end if; 282 283 -- Process pragma Unreserve_All_Interrupts. This overrides any settings 284 -- due to pragma Interrupt_State: 285 286 if Unreserve_All_Interrupts /= 0 then 287 Keep_Unmasked (SIGINT) := False; 288 Reserve (SIGINT) := False; 289 end if; 290 291 -- We do not really have Signal 0. We just use this value to identify 292 -- non-existent signals (see s-intnam.ads). Therefore, Signal should not 293 -- be used in all signal related operations hence mark it as reserved. 294 295 Reserve (0) := True; 296 end Initialize; 297 298end System.Interrupt_Management; 299