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) 2014-2018, 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-- In particular, you can freely distribute your programs built with the -- 23-- GNAT Pro compiler, including any required library run-time units, using -- 24-- any licensing terms of your choosing. See the AdaCore Software License -- 25-- for full details. -- 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 Android 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 function State (Int : Interrupt_ID) return Character; 90 pragma Import (C, State, "__gnat_get_interrupt_state"); 91 -- Get interrupt state. Defined in init.c The input argument is the 92 -- interrupt number, and the result is one of the following: 93 94 procedure Map_Signal 95 (signo : Signal; 96 siginfo : System.Address; 97 ucontext : System.Address); 98 -- This function identifies the Ada exception to be raised using the 99 -- information when the system received a synchronous signal. 100 101---------------- 102-- Map_Signal -- 103---------------- 104 105 procedure Map_Signal 106 (signo : Signal; 107 siginfo : System.Address; 108 ucontext : System.Address) 109 is 110 pragma Unreferenced (siginfo); 111 pragma Unreferenced (ucontext); 112 113 begin 114 -- Check that treatment of exception propagation here is consistent with 115 -- treatment of the abort signal in System.Task_Primitives.Operations. 116 117 case signo is 118 when SIGFPE => raise Constraint_Error; 119 when SIGILL => raise Program_Error; 120 when SIGSEGV => raise Storage_Error; 121 when SIGBUS => raise Storage_Error; 122 when others => null; 123 end case; 124 end Map_Signal; 125 126---------------------- 127-- Notify_Exception -- 128---------------------- 129 130 User : constant Character := 'u'; 131 Runtime : constant Character := 'r'; 132 Default : constant Character := 's'; 133 -- 'n' this interrupt not set by any Interrupt_State pragma 134 -- 'u' Interrupt_State pragma set state to User 135 -- 'r' Interrupt_State pragma set state to Runtime 136 -- 's' Interrupt_State pragma set state to System (use "default" 137 -- system handler) 138 139 procedure Notify_Exception 140 (signo : Signal; 141 siginfo : System.Address; 142 ucontext : System.Address); 143 -- This function is the signal handler and calls a trampoline subprogram 144 -- that adjusts the unwind information so the ARM unwinder can find it's 145 -- way back to the context of the originating subprogram. Compare with 146 -- __gnat_error_handler for non-tasking programs. 147 148 ---------------------- 149 -- Notify_Exception -- 150 ---------------------- 151 152 Signal_Mask : aliased sigset_t; 153 -- The set of signals handled by Notify_Exception 154 155 procedure Notify_Exception 156 (signo : Signal; 157 siginfo : System.Address; 158 ucontext : System.Address) 159 is 160 Result : Interfaces.C.int; 161 162 begin 163 -- With the __builtin_longjmp, the signal mask is not restored, so we 164 -- need to restore it explicitly. ??? We don't use __builtin_longjmp 165 -- anymore, so do we still need this? */ 166 167 Result := pthread_sigmask (SIG_UNBLOCK, Signal_Mask'Access, null); 168 pragma Assert (Result = 0); 169 170 -- Perform the necessary context adjustments prior to calling the 171 -- trampoline subprogram with the "real" signal handler. 172 173 Adjust_Context_For_Raise (signo, ucontext); 174 175 Signal_Trampoline (signo, siginfo, ucontext, Map_Signal'Address); 176 end Notify_Exception; 177 178 ---------------- 179 -- Initialize -- 180 ---------------- 181 182 Initialized : Boolean := False; 183 184 procedure Initialize is 185 act : aliased struct_sigaction; 186 old_act : aliased struct_sigaction; 187 Result : System.OS_Interface.int; 188 189 Use_Alternate_Stack : constant Boolean := 190 System.Task_Primitives.Alternate_Stack_Size /= 0; 191 -- Whether to use an alternate signal stack for stack overflows 192 193 begin 194 if Initialized then 195 return; 196 end if; 197 198 Initialized := True; 199 200 -- Need to call pthread_init very early because it is doing signal 201 -- initializations. 202 203 pthread_init; 204 205 Abort_Task_Interrupt := SIGADAABORT; 206 207 act.sa_handler := Notify_Exception'Address; 208 209 -- Setting SA_SIGINFO asks the kernel to pass more than just the signal 210 -- number argument to the handler when it is called. The set of extra 211 -- parameters includes a pointer to the interrupted context, which the 212 -- ZCX propagation scheme needs. 213 214 -- Most man pages for sigaction mention that sa_sigaction should be set 215 -- instead of sa_handler when SA_SIGINFO is on. In practice, the two 216 -- fields are actually union'ed and located at the same offset. 217 218 -- On some targets, we set sa_flags to SA_NODEFER so that during the 219 -- handler execution we do not change the Signal_Mask to be masked for 220 -- the Signal. 221 222 -- This is a temporary fix to the problem that the Signal_Mask is not 223 -- restored after the exception (longjmp) from the handler. The right 224 -- fix should be made in sigsetjmp so that we save the Signal_Set and 225 -- restore it after a longjmp. 226 227 -- We set SA_NODEFER to be compatible with what is done in 228 -- __gnat_error_handler. 229 230 Result := sigemptyset (Signal_Mask'Access); 231 pragma Assert (Result = 0); 232 233 -- Add signals that map to Ada exceptions to the mask 234 235 for J in Exception_Interrupts'Range loop 236 if State (Exception_Interrupts (J)) /= Default then 237 Result := 238 sigaddset 239 (Signal_Mask'Access, Signal (Exception_Interrupts (J))); 240 pragma Assert (Result = 0); 241 end if; 242 end loop; 243 244 act.sa_mask := Signal_Mask; 245 246 pragma Assert (Keep_Unmasked = (Interrupt_ID'Range => False)); 247 pragma Assert (Reserve = (Interrupt_ID'Range => False)); 248 249 -- Process state of exception signals 250 251 for J in Exception_Interrupts'Range loop 252 if State (Exception_Interrupts (J)) /= User then 253 Keep_Unmasked (Exception_Interrupts (J)) := True; 254 Reserve (Exception_Interrupts (J)) := True; 255 256 if State (Exception_Interrupts (J)) /= Default then 257 act.sa_flags := SA_NODEFER + SA_RESTART + SA_SIGINFO; 258 259 if Use_Alternate_Stack 260 and then Exception_Interrupts (J) = SIGSEGV 261 then 262 act.sa_flags := act.sa_flags + SA_ONSTACK; 263 end if; 264 265 Result := 266 sigaction 267 (Signal (Exception_Interrupts (J)), act'Unchecked_Access, 268 old_act'Unchecked_Access); 269 pragma Assert (Result = 0); 270 end if; 271 end if; 272 end loop; 273 274 if State (Abort_Task_Interrupt) /= User then 275 Keep_Unmasked (Abort_Task_Interrupt) := True; 276 Reserve (Abort_Task_Interrupt) := True; 277 end if; 278 279 -- Set SIGINT to unmasked state as long as it is not in "User" state. 280 -- Check for Unreserve_All_Interrupts last. 281 282 if State (SIGINT) /= User then 283 Keep_Unmasked (SIGINT) := True; 284 Reserve (SIGINT) := True; 285 end if; 286 287 -- Check all signals for state that requires keeping them unmasked and 288 -- reserved. 289 290 for J in Interrupt_ID'Range loop 291 if State (J) = Default or else State (J) = Runtime then 292 Keep_Unmasked (J) := True; 293 Reserve (J) := True; 294 end if; 295 end loop; 296 297 -- Add the set of signals that must always be unmasked for this target 298 299 for J in Unmasked'Range loop 300 Keep_Unmasked (Interrupt_ID (Unmasked (J))) := True; 301 Reserve (Interrupt_ID (Unmasked (J))) := True; 302 end loop; 303 304 -- Add target-specific reserved signals 305 306 for J in Reserved'Range loop 307 Reserve (Interrupt_ID (Reserved (J))) := True; 308 end loop; 309 310 -- Process pragma Unreserve_All_Interrupts. This overrides any settings 311 -- due to pragma Interrupt_State: 312 313 if Unreserve_All_Interrupts /= 0 then 314 Keep_Unmasked (SIGINT) := False; 315 Reserve (SIGINT) := False; 316 end if; 317 318 -- We do not really have Signal 0. We just use this value to identify 319 -- non-existent signals (see s-intnam.ads). Therefore, Signal should not 320 -- be used in all signal related operations hence mark it as reserved. 321 322 Reserve (0) := True; 323 end Initialize; 324 325end System.Interrupt_Management; 326