Attachment 316855 Details for Bug 461552 – Testcase

Testcase

clone-ptrace.c (text/plain), 3.40 KB, created by Denys Vlasenko on 2008-09-16 15:04:21 UTC

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Creator: Denys Vlasenko

Created: 2008-09-16 15:04:21 UTC

Size: 3.40 KB

patch

obsolete

>/* This software is provided 'as-is', without any express or implied
>   warranty.  In no event will the authors be held liable for any damages
>   arising from the use of this software.
>
>   Permission is granted to anyone to use this software for any purpose,
>   including commercial applications, and to alter it and redistribute it
>   freely.  */
>
>#ifndef _GNU_SOURCE
>#define _GNU_SOURCE
>#endif
>#include <assert.h>
>
>#ifdef __ia64__
>#define ia64_fpreg ia64_fpreg_DISABLE
>#define pt_all_user_regs pt_all_user_regs_DISABLE
>#endif /* __ia64__ */
>#include <sys/ptrace.h>
>#ifdef __ia64__
>#undef ia64_fpreg
>#undef pt_all_user_regs
>#endif /* __ia64__ */
>#include <linux/ptrace.h>
>#include <sys/types.h>
>#include <sys/user.h>
>#if defined __i386__ || defined __x86_64__
>#include <sys/debugreg.h>
>#endif
>
>#include <stdlib.h>
>#include <stdio.h>
>#include <string.h>
>#include <ctype.h>
>#include <pthread.h>
>#include <alloca.h>
>#include <signal.h>
>#include <errno.h>
>#include <sys/types.h>
>#include <sys/wait.h>
>#include <unistd.h>
>#include <linux/unistd.h>
>
>#define PTRACES 9999
>
>static int child_stack[4 * 1024];
>
>static int
>sleep_and_exit0 (void *unused)
>{
>  exit (0);
>}
>
>int
>main (int ac, char *av[])
>{
>  int l, status, ptraces;
>  pid_t pid, child, grandchild;
>
>  child = fork ();
>  if (child == -1)
>    {
>      perror ("fork");
>      exit (1);
>    }
>
>  if (child == 0)
>    {
>      // child
>      l = ptrace (PTRACE_TRACEME, 0, (void *) 0, (void *) 0);
>      assert (l == 0);
>      l = raise (SIGSTOP);
>      assert (l == 0);
>
>      child =
>	clone (sleep_and_exit0, child_stack + 2 * 1024,
>	       CLONE_PTRACE | SIGCHLD, NULL);
>      if (child == -1)
>	{
>	  perror ("fork in child");
>	  exit (1);
>	}
>
>      if (wait (NULL) == -1)
>	{
>	  perror ("wait for grandchild");
>	  exit (1);
>	}
>
>      usleep (20 * 1000);
>      exit (0);
>    }
>
>  // parent
>  usleep (20 * 1000);
>  pid = waitpid (-1, &status, 0);
>  assert (pid == child);
>//fprintf (stderr, "s:%d e:%d\n", WIFSTOPPED (status), WIFEXITED (status));
>  assert (WIFSTOPPED (status));
>//fprintf (stderr, "sig:%d\n", WSTOPSIG (status));
>  assert (WSTOPSIG (status) == SIGSTOP);
>
>  grandchild = -1;
>  for (ptraces = 0; ptraces < PTRACES; ptraces++)
>    {
>      if (pid > 0)
>	{
>	  errno = 0;
>	  ptrace (PTRACE_SYSCALL, pid, (void *) 1, (void *) 0);
>	  assert_perror (errno);
>	}
>
>      pid = waitpid (-1, &status, 0);
>      if (pid == child)
>	{
>//fprintf (stderr, "child: s:%d e:%d\n", WIFSTOPPED (status), WIFEXITED (status));
>	  if (grandchild == -2 && WIFEXITED (status))
>	    {
>//fprintf (stderr, "child exited %d\n", WEXITSTATUS (status));
>	      // Child is expected to exit only after grandchild
>	      assert (WEXITSTATUS (status) == 0);
>	      exit (0);
>	    }
>	  // Otherwise it must be a ptrace trap or grandchild exit
>	  assert (WIFSTOPPED (status));
>	  assert (WSTOPSIG (status) == SIGTRAP
>		  || WSTOPSIG (status) == SIGCHLD);
>	}
>      else if (grandchild == -1)
>	{
>	  grandchild = pid;
>//fprintf (stderr, "grandchild pid:%d\n", pid);
>	  // the bug was here: kernel didn't SIGSTOP CLONE_PTRACEd child
>	  assert (WIFSTOPPED (status));
>	  assert (WSTOPSIG (status) == SIGSTOP);
>	}
>      else
>	{
>	  // It must be grandchild, must be a ptrace trap or exit
>//fprintf (stderr, "grandchild\n", pid);
>	  assert (pid == grandchild);
>	  if (WIFEXITED (status))
>	    {
>	      assert (WEXITSTATUS (status) == 0);
>	      grandchild = -2;
>	      pid = -1;
>	    }
>	}
>    }
>//fprintf (stderr, "looping too long!\n");
>  assert (0);
>  return 1;
>}

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Attachments on bug 461552: 316855