gnu/dist/gdb6/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 <stdlib.h>
  25 #include <string.h>
  26 #include <sys/time.h>
  27
  28 enum level { MAIN, OUTER, INNER, LEAF, NR_LEVELS };
  29
  30 /* Levels completed flag.  */
  31 volatile enum level level = NR_LEVELS;
  32
  33 void catcher (int signal);
  34
  35 void
  36 thrower (enum level next_level, int sig, int itimer, int on_stack)
  37 {
  38   level = next_level;
  39   /* Set up the signal handler.  */
  40   {
  41     struct sigaction act;
  42     memset (&act, 0, sizeof (act));
  43     act.sa_handler = catcher;
  44     act.sa_flags |= on_stack;
  45     sigaction (sig, &act, NULL);
  46   }
  47   /* Set up a one-off timer.  A timer, rather than SIGSEGV, is used as
  48      after a timer handler finishes the interrupted code can safely
  49      resume.  */
  50   {
  51     struct itimerval itime;
  52     memset (&itime, 0, sizeof (itime));
  53     itime.it_value.tv_usec = 250 * 1000;
  54     setitimer (itimer, &itime, NULL);
  55   }
  56   /* Wait.  */
  57   while (level != LEAF);
  58 }
  59
  60 void
  61 catcher (int signal)
  62 {
  63   /* Find the next level.  */
  64   switch (level)
  65     {
  66     case MAIN:
  67       thrower (OUTER, SIGALRM, ITIMER_REAL, SA_ONSTACK);
  68       break;
  69     case OUTER:
  70       thrower (INNER, SIGVTALRM, ITIMER_VIRTUAL, SA_ONSTACK);
  71       break;
  72     case INNER:
  73       level = LEAF;
  74       return;
  75     }
  76 }
  77
  78
  79 main ()
  80 {
  81   /* Set up the altstack.  */
  82   {
  83     static char stack[SIGSTKSZ * NR_LEVELS];
  84     stack_t alt;
  85     memset (&alt, 0, sizeof (alt));
  86     alt.ss_sp = stack;
  87     alt.ss_size = SIGSTKSZ;
  88     alt.ss_flags = 0;
  89     if (sigaltstack (&alt, NULL) < 0)
  90       {
  91         perror ("sigaltstack");
  92         exit (0);
  93       }
  94   }
  95   level = MAIN;
  96   catcher (0);
  97 }