Attachment 159411 Details for Bug 248532 – Testcase.

Testcase.

stopped-sigcont-hang-0.c (text/plain), 2.98 KB, created by Jan Kratochvil on 2007-07-17 09:49:45 UTC

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Creator: Jan Kratochvil

Created: 2007-07-17 09:49:45 UTC

Size: 2.98 KB

patch

obsolete

>/* Copyright 2007 Free Software Foundation, Inc.
>
>   This program is free software; you can redistribute it and/or modify
>   it under the terms of the GNU General Public License as published by
>   the Free Software Foundation; either version 2 of the License, or
>   (at your option) any later version.
>
>   This program is distributed in the hope that it will be useful,
>   but WITHOUT ANY WARRANTY; without even the implied warranty of
>   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>   GNU General Public License for more details.
>
>   You should have received a copy of the GNU General Public License
>   along with this program; if not, write to the Free Software
>   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
>
>#define _GNU_SOURCE
>#include <signal.h>
>#include <unistd.h>
>#include <string.h>
>#include <stdio.h>
>#include <stdlib.h>
>#include <errno.h>
>#include <sys/wait.h>
>#include <sys/ptrace.h>
>#include <assert.h>
>#include <fcntl.h>
>#include <limits.h>
>#include <ctype.h>
>#include <linux/ptrace.h>
>
>#include <asm/unistd.h>
>#include <unistd.h>
>#define tkill(tid, sig) syscall (__NR_tkill, (tid), (sig))
>
>static pid_t child;
>
>static void
>cleanup (void)
>{
>  if (child != 0)
>    kill (child, SIGKILL);
>}
>
>static void
>handler_fail (int signo)
>{
>  cleanup ();
>
>  signal (SIGABRT, SIG_DFL);
>  abort ();
>}
>
>int main (void)
>{
>  pid_t got_pid;
>  int status;
>
>  setbuf (stdout, NULL);
>
>  child = fork ();
>  switch (child)
>    {
>      case -1:
>	abort ();
>      case 0:
>	raise (SIGSTOP);
>	for (;;)
>	  pause ();
>	/* NOTREACHED */
>      default:
>        break;
>    }
>  atexit (cleanup);
>  signal (SIGABRT, handler_fail);
>  signal (SIGALRM, handler_fail);
>  alarm (1);
>
>  /* Present here as it may happen before we - as a debugger - get started.
>     Without this WAITPID -> SIGSTOP the `tkill (child, SIGCONT)' call below is
>     not needed and the whole problem is no longer present.
>     Only removing the `tkill (child, SIGCONT)' call is not the solution.  */
>  {
>    int i;
>    siginfo_t siginfo;
>
>    i = waitid (P_PID, child, &siginfo, WEXITED | WSTOPPED | WCONTINUED);
>    assert (i == 0);
>    assert (siginfo.si_pid == child);
>    assert (siginfo.si_signo == SIGCHLD);
>    assert (siginfo.si_code == CLD_STOPPED);
>    assert (siginfo.si_status == SIGSTOP);
>  }
>
>  /* Here is a point where we - as a debugger - start to attach.  */
>  errno = 0;
>  ptrace (PTRACE_ATTACH, child, NULL, NULL);
>  assert_perror (errno);
>
>  /* `PTRACE_CONT, SIGSTOP' does not work in 100% cases as sometimes SIGSTOP
>     gets remembered by kernel during the first PTRACE_CONT later and we get
>     spurious SIGSTOP event.  Expecting the signal may get delivered to
>     a different task of the thread group.
>     `tkill (SIGSTOP)' has no effect in this moment (it is already stopped).  */
>  errno = 0;
>  tkill (child, SIGCONT);
>  assert_perror (errno);
>
>  got_pid = waitpid (child, &status, 0);
>  assert (got_pid == child);
>  assert (WIFSTOPPED (status));
>  assert (WSTOPSIG (status) == SIGCONT);
>
>  puts ("PASS");
>  return 0;
>}

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