| 1 | /* Temporarily install an alternate signal stack |
| 2 | |
| 3 | Copyright (C) 2019-2020 Free Software Foundation, Inc. |
| 4 | |
| 5 | This file is part of GDB. |
| 6 | |
| 7 | This program is free software; you can redistribute it and/or modify |
| 8 | it under the terms of the GNU General Public License as published by |
| 9 | the Free Software Foundation; either version 3 of the License, or |
| 10 | (at your option) any later version. |
| 11 | |
| 12 | This program is distributed in the hope that it will be useful, |
| 13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | GNU General Public License for more details. |
| 16 | |
| 17 | You should have received a copy of the GNU General Public License |
| 18 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 19 | |
| 20 | #ifndef GDBSUPPORT_ALT_STACK_H |
| 21 | #define GDBSUPPORT_ALT_STACK_H |
| 22 | |
| 23 | #include <signal.h> |
| 24 | |
| 25 | namespace gdb |
| 26 | { |
| 27 | |
| 28 | /* Try to set up an alternate signal stack for SIGSEGV handlers. |
| 29 | This allows us to handle SIGSEGV signals generated when the |
| 30 | normal process stack is exhausted. If this stack is not set |
| 31 | up (sigaltstack is unavailable or fails) and a SIGSEGV is |
| 32 | generated when the normal stack is exhausted then the program |
| 33 | will behave as though no SIGSEGV handler was installed. */ |
| 34 | class alternate_signal_stack |
| 35 | { |
| 36 | public: |
| 37 | alternate_signal_stack () |
| 38 | { |
| 39 | #ifdef HAVE_SIGALTSTACK |
| 40 | m_stack.reset ((char *) xmalloc (SIGSTKSZ)); |
| 41 | |
| 42 | stack_t stack; |
| 43 | stack.ss_sp = m_stack.get (); |
| 44 | stack.ss_size = SIGSTKSZ; |
| 45 | stack.ss_flags = 0; |
| 46 | |
| 47 | sigaltstack (&stack, &m_old_stack); |
| 48 | #endif |
| 49 | } |
| 50 | |
| 51 | ~alternate_signal_stack () |
| 52 | { |
| 53 | #ifdef HAVE_SIGALTSTACK |
| 54 | sigaltstack (&m_old_stack, nullptr); |
| 55 | #endif |
| 56 | } |
| 57 | |
| 58 | DISABLE_COPY_AND_ASSIGN (alternate_signal_stack); |
| 59 | |
| 60 | private: |
| 61 | |
| 62 | #ifdef HAVE_SIGALTSTACK |
| 63 | gdb::unique_xmalloc_ptr<char> m_stack; |
| 64 | stack_t m_old_stack; |
| 65 | #endif |
| 66 | }; |
| 67 | |
| 68 | } |
| 69 | |
| 70 | #endif /* GDBSUPPORT_ALT_STACK_H */ |