| 1 | /* This testcase is part of GDB, the GNU debugger. |
| 2 | |
| 3 | Copyright 2004, 2005, 2007 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 | */ |
| 19 | |
| 20 | #include <stdio.h> |
| 21 | #include <stdlib.h> |
| 22 | #include <string.h> |
| 23 | #include <signal.h> |
| 24 | #include <sys/time.h> |
| 25 | |
| 26 | static volatile int done[2]; |
| 27 | static volatile int repeats[2]; |
| 28 | static int itimer[2] = { ITIMER_REAL, ITIMER_VIRTUAL }; |
| 29 | static int alarm[2] = { SIGALRM, SIGVTALRM }; |
| 30 | |
| 31 | static void |
| 32 | handler (int sig) |
| 33 | { |
| 34 | int sigi; |
| 35 | switch (sig) |
| 36 | { |
| 37 | case SIGALRM: sigi = 0; break; |
| 38 | case SIGVTALRM: sigi = 1; break; |
| 39 | default: abort (); |
| 40 | } |
| 41 | if (repeats[sigi]++ > 3) |
| 42 | { |
| 43 | /* Hit with enough signals, cancel everything and get out. */ |
| 44 | { |
| 45 | struct itimerval itime; |
| 46 | memset (&itime, 0, sizeof (itime)); |
| 47 | setitimer (itimer[sigi], &itime, NULL); |
| 48 | } |
| 49 | { |
| 50 | struct sigaction action; |
| 51 | memset (&action, 0, sizeof (action)); |
| 52 | action.sa_handler = SIG_IGN; |
| 53 | sigaction (sig, &action, NULL); |
| 54 | } |
| 55 | done[sigi] = 1; |
| 56 | return; |
| 57 | } |
| 58 | /* Set up a nested virtual timer. */ |
| 59 | while (1) |
| 60 | { |
| 61 | /* Wait until a signal has become pending, that way when this |
| 62 | handler returns it will be immediatly delivered leading to |
| 63 | back-to-back signals. */ |
| 64 | sigset_t set; |
| 65 | sigemptyset (&set); |
| 66 | if (sigpending (&set) < 0) |
| 67 | { |
| 68 | perror ("sigrepeat"); |
| 69 | abort (); |
| 70 | } |
| 71 | if (sigismember (&set, sig)) |
| 72 | break; |
| 73 | } |
| 74 | } /* handler */ |
| 75 | |
| 76 | int |
| 77 | main () |
| 78 | { |
| 79 | int i; |
| 80 | /* Set up the signal handler. */ |
| 81 | for (i = 0; i < 2; i++) |
| 82 | { |
| 83 | struct sigaction action; |
| 84 | memset (&action, 0, sizeof (action)); |
| 85 | action.sa_handler = handler; |
| 86 | sigaction (alarm[i], &action, NULL); |
| 87 | } |
| 88 | |
| 89 | /* Set up a rapidly repeating timers. A timer, rather than SIGSEGV, |
| 90 | is used as after a timer handler returns the interrupted code can |
| 91 | safely resume. The intent is for the program to swamp GDB with a |
| 92 | backlog of pending signals. */ |
| 93 | for (i = 0; i < 2; i++) |
| 94 | { |
| 95 | struct itimerval itime; |
| 96 | memset (&itime, 0, sizeof (itime)); |
| 97 | itime.it_interval.tv_usec = 1; |
| 98 | itime.it_value.tv_usec = 250 * 1000; |
| 99 | setitimer (itimer[i], &itime, NULL); |
| 100 | } |
| 101 | |
| 102 | /* Wait. */ |
| 103 | while (!done[0] && !done[1]); /* infinite loop */ |
| 104 | return 0; |
| 105 | } |