131 lines
3.6 KiB
C
131 lines
3.6 KiB
C
/* Copyright (C) 1991, 1992, 1993, 1994, 1995 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If
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not, write to the Free Software Foundation, Inc., 675 Mass Ave,
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Cambridge, MA 02139, USA. */
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#include <ansidecl.h>
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#include <errno.h>
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#include <hurd.h>
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#include <hurd/resource.h>
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#include <cthreads.h> /* For `struct mutex'. */
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/* Initial maximum size of the data segment (32MB, which is arbitrary). */
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#define DATA_SIZE (32 * 1024 * 1024)
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/* Up to the page including this address is allocated from the kernel.
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This address is the data resource limit. */
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vm_address_t _hurd_data_end;
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/* Up to this address is actually available to the user.
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Pages beyond the one containing this address allow no access. */
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vm_address_t _hurd_brk;
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struct mutex _hurd_brk_lock;
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extern int __data_start, _end;
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/* Set the end of the process's data space to INADDR.
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Return 0 if successful, -1 if not. */
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int
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DEFUN(__brk, (inaddr), PTR inaddr)
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{
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int ret;
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HURD_CRITICAL_BEGIN;
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__mutex_lock (&_hurd_brk_lock);
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ret = _hurd_set_brk ((vm_address_t) inaddr);
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__mutex_unlock (&_hurd_brk_lock);
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HURD_CRITICAL_END;
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return ret;
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}
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weak_alias (__brk, brk)
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int
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_hurd_set_brk (vm_address_t addr)
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{
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error_t err;
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vm_address_t pagend = round_page (addr);
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vm_address_t pagebrk = round_page (_hurd_brk);
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long int rlimit;
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if (pagend <= pagebrk)
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{
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if (pagend < pagebrk)
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/* Make that memory inaccessible. */
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__vm_protect (__mach_task_self (), pagend, pagebrk - pagend,
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0, VM_PROT_NONE);
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_hurd_brk = addr;
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return 0;
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}
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__mutex_lock (&_hurd_rlimit_lock);
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rlimit = _hurd_rlimits[RLIMIT_DATA].rlim_cur;
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__mutex_unlock (&_hurd_rlimit_lock);
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if (addr - (vm_address_t) &__data_start > rlimit)
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{
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/* Need to increase the resource limit. */
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errno = ENOMEM;
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return -1;
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}
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/* Make the memory accessible. */
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if (err = __vm_protect (__mach_task_self (), pagebrk, pagend - pagebrk,
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0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE))
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{
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errno = err;
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return -1;
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}
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_hurd_brk = addr;
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return 0;
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}
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static void
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init_brk (void)
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{
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vm_address_t pagend;
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__mutex_init (&_hurd_brk_lock);
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/* If _hurd_brk is already set, don't change it. The assumption is that
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it was set in a previous run before something like Emacs's unexec was
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called and dumped all the data up to the break at that point. */
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if (_hurd_brk == 0)
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_hurd_brk = (vm_address_t) &_end;
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pagend = round_page (_hurd_brk);
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_hurd_data_end = (vm_address_t) &__data_start + DATA_SIZE;
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if (pagend < _hurd_data_end)
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{
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/* We use vm_map to allocate and change permissions atomically. */
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if (__vm_map (__mach_task_self (), &pagend, _hurd_data_end - pagend,
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0, 0, MACH_PORT_NULL, 0, 0,
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0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE,
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VM_INHERIT_COPY))
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/* Couldn't allocate the memory. The break will be very short. */
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_hurd_data_end = pagend;
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}
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(void) &init_brk; /* Avoid ``defined but not used'' warning. */
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}
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text_set_element (_hurd_preinit_hook, init_brk);
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