gdb/testsuite/gdb.base/fork-running-state.c

   1 /* This testcase is part of GDB, the GNU debugger.
   2
   3    Copyright 2015-2023 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 #include <unistd.h>
  19 #include <stdio.h>
  20 #include <sys/types.h>
  21 #include <sys/wait.h>
  22 #include <errno.h>
  23 #include <signal.h>
  24
  25 int save_parent;
  26
  27 /* Variable set by GDB.  If true, then a fork child (or parent) exits
  28    if its parent (or child) exits.  Otherwise the process waits
  29    forever until either GDB or the alarm kills it.  */
  30 volatile int exit_if_relative_exits = 0;
  31
  32 /* The fork child.  Just runs forever.  */
  33
  34 static int
  35 fork_child (void)
  36 {
  37   /* Don't run forever.  */
  38   alarm (180);
  39
  40   while (1)
  41     {
  42       if (exit_if_relative_exits)
  43         {
  44           sleep (1);
  45
  46           /* Exit if GDB kills the parent.  */
  47           if (getppid () != save_parent)
  48             break;
  49           if (kill (getppid (), 0) != 0)
  50             break;
  51         }
  52       else
  53         pause ();
  54     }
  55
  56   return 0;
  57 }
  58
  59 /* The fork parent.  Just runs forever.  */
  60
  61 static int
  62 fork_parent (void)
  63 {
  64   /* Don't run forever.  */
  65   alarm (180);
  66
  67   while (1)
  68     {
  69       if (exit_if_relative_exits)
  70         {
  71           int res = wait (NULL);
  72           if (res == -1 && errno == EINTR)
  73             continue;
  74           else if (res == -1)
  75             {
  76               perror ("wait");
  77               return 1;
  78             }
  79           else
  80             return 0;
  81         }
  82       else
  83         pause ();
  84     }
  85
  86   return 0;
  87 }
  88
  89 int
  90 main (void)
  91 {
  92   pid_t pid;
  93
  94   save_parent = getpid ();
  95
  96   /* The parent and child should basically run forever without
  97      tripping on any debug event.  We want to check that GDB updates
  98      the parent and child running states correctly right after the
  99      fork.  */
 100   pid = fork ();
 101   if (pid > 0)
 102     return fork_parent ();
 103   else if (pid == 0)
 104     return fork_child ();
 105   else
 106     {
 107       perror ("fork");
 108       return 1;
 109     }
 110 }