| 1 | /* This testcase is part of GDB, the GNU debugger. |
| 2 | |
| 3 | Copyright 2004-2016 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 | |
| 24 | enum level { MAIN, OUTER, INNER, LEAF, NR_LEVELS }; |
| 25 | |
| 26 | /* Levels completed flag. */ |
| 27 | volatile enum level level = NR_LEVELS; |
| 28 | |
| 29 | void catcher (int signal); |
| 30 | |
| 31 | void |
| 32 | thrower (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 | |
| 56 | void |
| 57 | catcher (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 | |
| 75 | int |
| 76 | main () |
| 77 | { |
| 78 | /* Set up the altstack. */ |
| 79 | { |
| 80 | static char stack[SIGSTKSZ * NR_LEVELS]; |
| 81 | stack_t alt; |
| 82 | memset (&alt, 0, sizeof (alt)); |
| 83 | alt.ss_sp = stack; |
| 84 | alt.ss_size = SIGSTKSZ; |
| 85 | alt.ss_flags = 0; |
| 86 | if (sigaltstack (&alt, NULL) < 0) |
| 87 | { |
| 88 | perror ("sigaltstack"); |
| 89 | exit (0); |
| 90 | } |
| 91 | } |
| 92 | level = MAIN; |
| 93 | catcher (0); |
| 94 | return 0; |
| 95 | } |