1/* This testcase is part of GDB, the GNU debugger. 2 3 Copyright 2004, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc. 4 5 This program is free software; you can redistribute it and/or modify 6 it under the terms of the GNU General Public License as published by 7 the Free Software Foundation; either version 3 of the License, or 8 (at your option) any later version. 9 10 This program is distributed in the hope that it will be useful, 11 but WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 GNU General Public License for more details. 14 15 You should have received a copy of the GNU General Public License 16 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 17 18#include <signal.h> 19#include <stdio.h> 20#include <stdlib.h> 21#include <string.h> 22#include <sys/time.h> 23 24enum level { MAIN, OUTER, INNER, LEAF, NR_LEVELS }; 25 26/* Levels completed flag. */ 27volatile enum level level = NR_LEVELS; 28 29void catcher (int signal); 30 31void 32thrower (enum level next_level, int sig, int itimer, int on_stack) 33{ 34 level = next_level; 35 /* Set up the signal handler. */ 36 { 37 struct sigaction act; 38 memset (&act, 0, sizeof (act)); 39 act.sa_handler = catcher; 40 act.sa_flags |= on_stack; 41 sigaction (sig, &act, NULL); 42 } 43 /* Set up a one-off timer. A timer, rather than SIGSEGV, is used as 44 after a timer handler finishes the interrupted code can safely 45 resume. */ 46 { 47 struct itimerval itime; 48 memset (&itime, 0, sizeof (itime)); 49 itime.it_value.tv_usec = 250 * 1000; 50 setitimer (itimer, &itime, NULL); 51 } 52 /* Wait. */ 53 while (level != LEAF); 54} 55 56void 57catcher (int signal) 58{ 59 /* Find the next level. */ 60 switch (level) 61 { 62 case MAIN: 63 thrower (OUTER, SIGALRM, ITIMER_REAL, SA_ONSTACK); 64 break; 65 case OUTER: 66 thrower (INNER, SIGVTALRM, ITIMER_VIRTUAL, SA_ONSTACK); 67 break; 68 case INNER: 69 level = LEAF; 70 return; 71 } 72} 73 74 75main () 76{ 77 /* Set up the altstack. */ 78 { 79 static char stack[SIGSTKSZ * NR_LEVELS]; 80 stack_t alt; 81 memset (&alt, 0, sizeof (alt)); 82 alt.ss_sp = stack; 83 alt.ss_size = SIGSTKSZ; 84 alt.ss_flags = 0; 85 if (sigaltstack (&alt, NULL) < 0) 86 { 87 perror ("sigaltstack"); 88 exit (0); 89 } 90 } 91 level = MAIN; 92 catcher (0); 93} 94