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/* Copyright (C) 1991, 1992, 1993, 1994, 1995 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA. */
#include <ansidecl.h>
#include <errno.h>
#include <hurd.h>
#include <hurd/resource.h>
#include <cthreads.h> /* For `struct mutex'. */
/* Initial maximum size of the data segment (32MB, which is arbitrary). */
#define DATA_SIZE (32 * 1024 * 1024)
/* Up to the page including this address is allocated from the kernel.
This address is the data resource limit. */
vm_address_t _hurd_data_end;
/* Up to this address is actually available to the user.
Pages beyond the one containing this address allow no access. */
vm_address_t _hurd_brk;
struct mutex _hurd_brk_lock;
extern int __data_start, _end;
/* Set the end of the process's data space to INADDR.
Return 0 if successful, -1 if not. */
int
DEFUN(__brk, (inaddr), PTR inaddr)
{
int ret;
HURD_CRITICAL_BEGIN;
__mutex_lock (&_hurd_brk_lock);
ret = _hurd_set_brk ((vm_address_t) inaddr);
__mutex_unlock (&_hurd_brk_lock);
HURD_CRITICAL_END;
return ret;
}
weak_alias (__brk, brk)
int
_hurd_set_brk (vm_address_t addr)
{
error_t err;
vm_address_t pagend = round_page (addr);
vm_address_t pagebrk = round_page (_hurd_brk);
long int rlimit;
if (pagend <= pagebrk)
{
if (pagend < pagebrk)
/* Make that memory inaccessible. */
__vm_protect (__mach_task_self (), pagend, pagebrk - pagend,
0, VM_PROT_NONE);
_hurd_brk = addr;
return 0;
}
__mutex_lock (&_hurd_rlimit_lock);
rlimit = _hurd_rlimits[RLIMIT_DATA].rlim_cur;
__mutex_unlock (&_hurd_rlimit_lock);
if (addr - (vm_address_t) &__data_start > rlimit)
{
/* Need to increase the resource limit. */
errno = ENOMEM;
return -1;
}
/* Make the memory accessible. */
if (err = __vm_protect (__mach_task_self (), pagebrk, pagend - pagebrk,
0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE))
{
errno = err;
return -1;
}
_hurd_brk = addr;
return 0;
}
static void
init_brk (void)
{
vm_address_t pagend;
__mutex_init (&_hurd_brk_lock);
/* If _hurd_brk is already set, don't change it. The assumption is that
it was set in a previous run before something like Emacs's unexec was
called and dumped all the data up to the break at that point. */
if (_hurd_brk == 0)
_hurd_brk = (vm_address_t) &_end;
pagend = round_page (_hurd_brk);
_hurd_data_end = (vm_address_t) &__data_start + DATA_SIZE;
if (pagend < _hurd_data_end)
{
/* We use vm_map to allocate and change permissions atomically. */
if (__vm_map (__mach_task_self (), &pagend, _hurd_data_end - pagend,
0, 0, MACH_PORT_NULL, 0, 0,
0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE,
VM_INHERIT_COPY))
/* Couldn't allocate the memory. The break will be very short. */
_hurd_data_end = pagend;
}
(void) &init_brk; /* Avoid ``defined but not used'' warning. */
}
text_set_element (_hurd_preinit_hook, init_brk);
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