binutils-gdb/gdb/i386obsd-nat.c

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/* Native-dependent code for OpenBSD/i386.
Copyright 2002, 2003, 2004 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 <sys/param.h>
#include <sys/sysctl.h>
#include "i386-tdep.h"
/* Prevent warning from -Wmissing-prototypes. */
void _initialize_i386obsd_nat (void);
void
_initialize_i386obsd_nat (void)
{
/* OpenBSD provides a vm.psstrings 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. This is especially
important for OpenBSD, since it uses a different memory layout
than NetBSD, yet we cannot distinguish between the two.
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 VM_PSSTRINGS
{
struct _ps_strings _ps;
int mib[2];
size_t len;
mib[0] = CTL_VM;
mib[1] = VM_PSSTRINGS;
len = sizeof (_ps);
if (sysctl (mib, 2, &_ps, &len, NULL, 0) == 0)
{
i386obsd_sigtramp_start_addr = (u_long) _ps.val - 128;
i386obsd_sigtramp_end_addr = (u_long) _ps.val;
}
}
#endif
}