From 28f540f45bbacd939bfd07f213bcad2bf730b1bf Mon Sep 17 00:00:00 2001 From: Roland McGrath Date: Sat, 18 Feb 1995 01:27:10 +0000 Subject: initial import --- sysdeps/mach/hurd/brk.c | 130 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 130 insertions(+) create mode 100644 sysdeps/mach/hurd/brk.c (limited to 'sysdeps/mach/hurd/brk.c') diff --git a/sysdeps/mach/hurd/brk.c b/sysdeps/mach/hurd/brk.c new file mode 100644 index 0000000000..a96286b2d9 --- /dev/null +++ b/sysdeps/mach/hurd/brk.c @@ -0,0 +1,130 @@ +/* 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 +#include +#include +#include +#include /* 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); -- cgit 1.4.1