| /**************************************************************************** |
| * * |
| * GNAT COMPILER COMPONENTS * |
| * * |
| * S I G T R A M P * |
| * * |
| * C Header File * |
| * * |
| * Copyright (C) 2011-2014, Free Software Foundation, Inc. * |
| * * |
| * GNAT is free software; you can redistribute it and/or modify it under * |
| * terms of the GNU General Public License as published by the Free Soft- * |
| * ware Foundation; either version 3, or (at your option) any later ver- * |
| * sion. GNAT is distributed in the hope that it will be useful, but WITH- * |
| * OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY * |
| * or FITNESS FOR A PARTICULAR PURPOSE. * |
| * * |
| * As a special exception under Section 7 of GPL version 3, you are granted * |
| * additional permissions described in the GCC Runtime Library Exception, * |
| * version 3.1, as published by the Free Software Foundation. * |
| * * |
| * You should have received a copy of the GNU General Public License and * |
| * a copy of the GCC Runtime Library Exception along with this program; * |
| * see the files COPYING3 and COPYING.RUNTIME respectively. If not, see * |
| * <http://www.gnu.org/licenses/>. * |
| * * |
| * GNAT was originally developed by the GNAT team at New York University. * |
| * Extensive contributions were provided by Ada Core Technologies Inc. * |
| * * |
| ****************************************************************************/ |
| |
| /* On targets where this is implemented, we resort to a signal handler |
| trampoline to set-up the DWARF Call Frame Information that let unwinders |
| walk through the signal frame up into the interrupted application code. |
| This file introduces the relevant declarations. */ |
| |
| /* This file should only be #included on targets that do implement the |
| trampoline, which needs to expose the following interface: */ |
| |
| #ifdef __cplusplus |
| extern "C" { |
| #endif |
| |
| #ifdef __ANDROID__ |
| #include <stdlib.h> |
| #include <asm/signal.h> |
| #include <asm/sigcontext.h> |
| |
| /* Android SDK doesn't define these structs */ |
| typedef struct sigcontext mcontext_t; |
| |
| typedef struct ucontext |
| { |
| unsigned long uc_flags; |
| struct ucontext *uc_link; |
| stack_t uc_stack; |
| mcontext_t uc_mcontext; |
| } ucontext_t; |
| #endif |
| |
| /* This typedef signature sometimes conflicts with the sighandler_t from |
| system headers so call it something unique. */ |
| typedef void __sigtramphandler_t (int signo, void *siginfo, void *sigcontext); |
| |
| void __gnat_sigtramp (int signo, void *siginfo, void *sigcontext, |
| __sigtramphandler_t * handler); |
| |
| /* To be called from an established signal handler. Setup the DWARF CFI |
| bits letting unwinders walk through the signal frame up into the |
| interrupted application code, and then call HANDLER (SIGNO, SIGINFO, |
| SIGCONTEXT). |
| |
| The sigtramp construct makes it so that the unwinder jumps over it + the |
| signal handler + the kernel frame. For a typical backtrace from the raise |
| function: |
| |
| #0 __gnat_Unwind_RaiseException |
| #1 Raise_From_Signal_Handler |
| #2 __gnat_map_signal |
| #3 __gnat_sigtramp |
| #4 __gnat_error_handler |
| #5 <kernel frame> |
| #6 interrupted function |
| |
| The unwinder will unwind frames 0, 1 and 2 as usual. But the CFI of frame |
| 3 is set up as if the caller of frame 3 was frame 6 so, when frame 3 is |
| unwound, the unwinder ends up in frame 6 directly. It's possible to do so |
| since the kernel has saved the context of frame 6 and passed it on to |
| __gnat_sigtramp. */ |
| |
| #ifdef __cplusplus |
| } |
| #endif |