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/* Native-dependent code for FreeBSD/i386.

   Copyright 2001, 2002 Free Software Foundation, Inc.

   This file is part of GDB.

   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.  */

#include "defs.h"

#include "inferior.h"

#include "regcache.h"

#include <sys/types.h>

#include <sys/ptrace.h>

#include <sys/sysctl.h>

/* Prevent warning from -Wmissing-prototypes.  */

void _initialize_i386fbsd_nat (void);

/* Resume execution of the inferior process.

   If STEP is nonzero, single-step it.

   If SIGNAL is nonzero, give it that signal.  */

void

child_resume (ptid_t ptid, int step, enum target_signal signal)

{

  pid_t pid = ptid_get_pid (ptid);

  int request = PT_STEP;

  if (pid == -1)

    /* Resume all threads.  This only gets used in the non-threaded

       case, where "resume all threads" and "resume inferior_ptid" are

       the same.  */

    pid = ptid_get_pid (inferior_ptid);

  if (!step)

    {

      unsigned int eflags;

      /* Workaround for a bug in FreeBSD.  Make sure that the trace

         flag is off when doing a continue.  There is a code path

         through the kernel which leaves the flag set when it should

         have been cleared.  If a process has a signal pending (such

         as SIGALRM) and we do a PT_STEP, the process never really has

         a chance to run because the kernel needs to notify the

         debugger that a signal is being sent.  Therefore, the process

         never goes through the kernel's trap() function which would

         normally clear it.  */

      eflags = read_register (PS_REGNUM);

      if (eflags & 0x0100)

        write_register (PS_REGNUM, eflags & ~0x0100);

      request = PT_CONTINUE;

    }

  /* An addres of (caddr_t) 1 tells ptrace to continue from where it

     was.  (If GDB wanted it to start some other way, we have already

     written a new PC value to the child.)  */

  if (ptrace (request, pid, (caddr_t) 1,

              target_signal_to_host (signal)) == -1)

    perror_with_name ("ptrace");

}

void

_initialize_i386fbsd_nat (void)

{

  /* FreeBSD provides a kern.ps_strings sysctl that we can use to

     locate the sigtramp.  That way we can still recognize a sigtramp

     if its location is changed in a new kernel.  Of course this is

     still based on the assumption that the sigtramp is placed

     directly under the location where the program arguments and

     environment can be found.  */

#ifdef KERN_PS_STRINGS

  {

    int mib[2];

    int ps_strings;

    size_t len;

    extern CORE_ADDR i386fbsd_sigtramp_start;

    extern CORE_ADDR i386fbsd_sigtramp_end;

    mib[0] = CTL_KERN;

    mib[1] = KERN_PS_STRINGS;

    len = sizeof (ps_strings);

    if (sysctl (mib, 2, &ps_strings, &len, NULL, 0) == 0)

      {

        i386fbsd_sigtramp_start = ps_strings - 128;

        i386fbsd_sigtramp_end = ps_strings;

      }

  }

#endif

}