gdb/testsuite/gdb.base/sigstep.c

   1 /* This testcase is part of GDB, the GNU debugger.
   2
   3    Copyright 2004-2014 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 <string.h>
  22 #include <signal.h>
  23 #include <sys/time.h>
  24 #include <errno.h>
  25
  26 static volatile int done;
  27 static volatile int dummy;
  28
  29 static void
  30 handler (int sig)
  31 {
  32   /* This is more than one write so that the breakpoint location below
  33      is more than one instruction away.  */
  34   done = 1;
  35   done = 1;
  36   done = 1;
  37   done = 1; /* other handler location */
  38 } /* handler */
  39
  40 struct itimerval itime;
  41 struct sigaction action;
  42
  43 /* The enum is so that GDB can easily see these macro values.  */
  44 enum {
  45   itimer_real = ITIMER_REAL,
  46   itimer_virtual = ITIMER_VIRTUAL
  47 } itimer = ITIMER_VIRTUAL;
  48
  49 int
  50 main ()
  51 {
  52
  53   int res;
  54   /* Set up the signal handler.  */
  55   memset (&action, 0, sizeof (action));
  56   action.sa_handler = handler;
  57   sigaction (SIGVTALRM, &action, NULL);
  58   sigaction (SIGALRM, &action, NULL);
  59
  60   /* The values needed for the itimer.  This needs to be at least long
  61      enough for the setitimer() call to return.  */
  62   memset (&itime, 0, sizeof (itime));
  63   itime.it_value.tv_usec = 250 * 1000;
  64
  65   /* Loop for ever, constantly taking an interrupt.  */
  66   while (1)
  67     {
  68       /* Set up a one-off timer.  A timer, rather than SIGSEGV, is
  69          used as after a timer handler finishes the interrupted code
  70          can safely resume.  */
  71       res = setitimer (itimer, &itime, NULL);
  72       if (res == -1)
  73         {
  74           printf ("First call to setitimer failed, errno = %d\r\n",errno);
  75           itimer = ITIMER_REAL;
  76           res = setitimer (itimer, &itime, NULL);
  77           if (res == -1)
  78             {
  79               printf ("Second call to setitimer failed, errno = %d\r\n",errno);
  80               return 1;
  81             }
  82         }
  83       /* Wait.  Issue a couple writes to a dummy volatile var to be
  84          reasonably sure our simple "get-next-pc" logic doesn't
  85          stumble on branches.  */
  86       dummy = 0; dummy = 0; while (!done);
  87       done = 0;
  88     }
  89   return 0;
  90 }