gdb/testsuite/gdb.threads/detach-step-over.c

   1 /* This testcase is part of GDB, the GNU debugger.
   2
   3    Copyright 2021-2022 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 #define _GNU_SOURCE
  19 #include <assert.h>
  20 #include <pthread.h>
  21 #include <stdlib.h>
  22 #include <stdio.h>
  23 #include <unistd.h>
  24 #include <string.h>
  25 #include <signal.h>
  26
  27 /* Number of threads we'll create.  */
  28 int n_threads = 10;
  29
  30 int mypid;
  31
  32 static void
  33 setup_done (void)
  34 {
  35 }
  36
  37 /* Entry point for threads.  Loops forever.  */
  38
  39 void *
  40 thread_func (void *arg)
  41 {
  42   /* Avoid setting the breakpoint at an instruction that wouldn't
  43      require a fixup phase, like a branch/jump.  In such a case, even
  44      if GDB manages to detach the inferior with an incomplete
  45      displaced step, GDB inferior may still not crash.  A breakpoint
  46      at a line that increments a variable is good bet that we end up
  47      setting a breakpoint at an instruction that will require a fixup
  48      phase to move the PC from the scratch pad to the instruction
  49      after the breakpoint.  */
  50   volatile unsigned counter = 0;
  51
  52   while (1)
  53     {
  54       counter++; /* Set breakpoint here.  */
  55       counter++;
  56       counter++;
  57     }
  58
  59   return NULL;
  60 }
  61
  62 /* Allow for as much timeout as DejaGnu wants, plus a bit of
  63    slack.  */
  64 #define SECONDS (TIMEOUT + 20)
  65
  66 /* We'll exit after this many seconds.  */
  67 unsigned int seconds_left = SECONDS;
  68
  69 /* GDB sets this whenever it's about to start a new detach/attach
  70    sequence.  We react by resetting the seconds-left counter.  */
  71 volatile int again = 0;
  72
  73 int
  74 main (int argc, char **argv)
  75 {
  76   int i;
  77
  78   signal (SIGUSR1, SIG_IGN);
  79
  80   mypid = getpid ();
  81   setup_done ();
  82
  83   if (argc > 1)
  84     n_threads = atoi (argv[1]);
  85
  86   /* Spawn the test threads.  */
  87   for (i = 0; i < n_threads; ++i)
  88     {
  89       pthread_t child;
  90       int rc;
  91
  92       rc = pthread_create (&child, NULL, thread_func, NULL);
  93       assert (rc == 0);
  94     }
  95
  96   /* Exit after a while if GDB is gone/crashes.  But wait long enough
  97      for one attach/detach sequence done by the .exp file.  */
  98   while (--seconds_left > 0)
  99     {
 100       sleep (1);
 101
 102       if (again)
 103         {
 104           /* GDB should be reattaching soon.  Restart the timer.  */
 105           again = 0;
 106           seconds_left = SECONDS;
 107         }
 108     }
 109
 110   printf ("timeout, exiting\n");
 111   return 0;
 112 }