gdb/testsuite/gdb.base/sigstep.c

   1 /* This testcase is part of GDB, the GNU debugger.
   2
   3    Copyright 2004-2021 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 static volatile int no_handler;
  29
  30 static void
  31 handler (int sig)
  32 {
  33   /* This is more than one write so that the breakpoint location below
  34      is more than one instruction away.  */
  35   done = 1;
  36   done = 1;
  37   done = 1;
  38   done = 1; /* other handler location */
  39 } /* handler */
  40
  41 struct itimerval itime;
  42 struct sigaction action;
  43
  44 /* The enum is so that GDB can easily see these macro values.  */
  45 enum {
  46   itimer_real = ITIMER_REAL,
  47   itimer_virtual = ITIMER_VIRTUAL
  48 } itimer = ITIMER_VIRTUAL;
  49
  50 int
  51 main ()
  52 {
  53   int res;
  54
  55   /* Set up the signal handler.  */
  56   memset (&action, 0, sizeof (action));
  57   action.sa_handler = no_handler ? SIG_IGN : handler;
  58   sigaction (SIGVTALRM, &action, NULL);
  59   sigaction (SIGALRM, &action, NULL);
  60
  61   /* The values needed for the itimer.  This needs to be at least long
  62      enough for the setitimer() call to return.  */
  63   memset (&itime, 0, sizeof (itime));
  64   itime.it_value.tv_usec = 250 * 1000;
  65
  66   /* Loop for ever, constantly taking an interrupt.  */
  67   while (1)
  68     {
  69       /* Set up a one-off timer.  A timer, rather than SIGSEGV, is
  70          used as after a timer handler finishes the interrupted code
  71          can safely resume.  */
  72       res = setitimer (itimer, &itime, NULL);
  73       if (res == -1)
  74         {
  75           printf ("First call to setitimer failed, errno = %d\r\n",errno);
  76           itimer = ITIMER_REAL;
  77           res = setitimer (itimer, &itime, NULL);
  78           if (res == -1)
  79             {
  80               printf ("Second call to setitimer failed, errno = %d\r\n",errno);
  81               return 1;
  82             }
  83         }
  84       /* Wait.  Issue a couple writes to a dummy volatile var to be
  85          reasonably sure our simple "get-next-pc" logic doesn't
  86          stumble on branches.  */
  87       dummy = 0; dummy = 0; while (!done);
  88       done = 0;
  89     }
  90   return 0;
  91 }