gdb/testsuite/gdb.base/sigaltstack.c

   1 /* This testcase is part of GDB, the GNU debugger.
   2
   3    Copyright 2004 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 2 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, write to the Free Software
  17    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  18
  19    Please email any bugs, comments, and/or additions to this file to:
  20    bug-gdb@prep.ai.mit.edu  */
  21
  22 #include <signal.h>
  23 #include <stdio.h>
  24 #include <sys/time.h>
  25
  26 enum level { MAIN, OUTER, INNER, LEAF, NR_LEVELS };
  27
  28 /* Levels completed flag.  */
  29 volatile enum level level = NR_LEVELS;
  30
  31 void catcher (int signal);
  32
  33 void
  34 thrower (enum level next_level, int sig, int itimer, int on_stack)
  35 {
  36   level = next_level;
  37   /* Set up the signal handler.  */
  38   {
  39     struct sigaction act;
  40     memset (&act, 0, sizeof (act));
  41     act.sa_handler = catcher;
  42     act.sa_flags |= on_stack;
  43     sigaction (sig, &act, NULL);
  44   }
  45   /* Set up a one-off timer.  A timer, rather than SIGSEGV, is used as
  46      after a timer handler finishes the interrupted code can safely
  47      resume.  */
  48   {
  49     struct itimerval itime;
  50     memset (&itime, 0, sizeof (itime));
  51     itime.it_value.tv_usec = 250 * 1000;
  52     setitimer (itimer, &itime, NULL);
  53   }
  54   /* Wait.  */
  55   while (level != LEAF);
  56 }
  57
  58 void
  59 catcher (int signal)
  60 {
  61   /* Find the next level.  */
  62   switch (level)
  63     {
  64     case MAIN:
  65       thrower (OUTER, SIGALRM, ITIMER_REAL, SA_ONSTACK);
  66       break;
  67     case OUTER:
  68       thrower (INNER, SIGVTALRM, ITIMER_VIRTUAL, SA_ONSTACK);
  69       break;
  70     case INNER:
  71       level = LEAF;
  72       return;
  73     }
  74 }
  75
  76
  77 main ()
  78 {
  79   /* Set up the altstack.  */
  80   {
  81     static char stack[SIGSTKSZ * NR_LEVELS];
  82     struct sigaltstack alt;
  83     memset (&alt, 0, sizeof (alt));
  84     alt.ss_sp = stack;
  85     alt.ss_size = SIGSTKSZ;
  86     alt.ss_flags = 0;
  87     if (sigaltstack (&alt, NULL) < 0)
  88       {
  89         perror ("sigaltstack");
  90         exit (0);
  91       }
  92   }
  93   level = MAIN;
  94   catcher (0);
  95 }