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/*
* The contents of this file are subject to the Mozilla Public
* License Version 1.1 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS
* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
* implied. See the License for the specific language governing
* rights and limitations under the License.
*
* The Original Code is the Netscape Portable Runtime library.
*
* The Initial Developer of the Original Code is Netscape
* Communications Corporation. Portions created by Netscape are
* Copyright (C) 1994-2000 Netscape Communications Corporation. All
* Rights Reserved.
*
* Contributor(s): Silicon Graphics, Inc.
*
* Portions created by SGI are Copyright (C) 2000-2001 Silicon
* Graphics, Inc. All Rights Reserved.
*
* Alternatively, the contents of this file may be used under the
* terms of the GNU General Public License Version 2 or later (the
* "GPL"), in which case the provisions of the GPL are applicable
* instead of those above. If you wish to allow use of your
* version of this file only under the terms of the GPL and not to
* allow others to use your version of this file under the MPL,
* indicate your decision by deleting the provisions above and
* replace them with the notice and other provisions required by
* the GPL. If you do not delete the provisions above, a recipient
* may use your version of this file under either the MPL or the
* GPL.
*/
/*
* This file is derived directly from Netscape Communications Corporation,
* and consists of extensive modifications made during the year(s) 1999-2000.
*/
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/mman.h>
#include "common.h"
/* How much space to leave between the stacks, at each end */
#define REDZONE _ST_PAGE_SIZE
_st_clist_t _st_free_stacks = ST_INIT_STATIC_CLIST(&_st_free_stacks);
int _st_num_free_stacks = 0;
int _st_randomize_stacks = 0;
static char *_st_new_stk_segment(int size);
_st_stack_t *_st_stack_new(int stack_size)
{
_st_clist_t *qp;
_st_stack_t *ts;
int extra;
for (qp = _st_free_stacks.next; qp != &_st_free_stacks; qp = qp->next) {
ts = _ST_THREAD_STACK_PTR(qp);
if (ts->stk_size >= stack_size) {
/* Found a stack that is big enough */
ST_REMOVE_LINK(&ts->links);
_st_num_free_stacks--;
ts->links.next = NULL;
ts->links.prev = NULL;
return ts;
}
}
/* Make a new thread stack object. */
if ((ts = (_st_stack_t *)calloc(1, sizeof(_st_stack_t))) == NULL)
return NULL;
extra = _st_randomize_stacks ? _ST_PAGE_SIZE : 0;
ts->vaddr_size = stack_size + 2*REDZONE + extra;
ts->vaddr = _st_new_stk_segment(ts->vaddr_size);
if (!ts->vaddr) {
free(ts);
return NULL;
}
ts->stk_size = stack_size;
ts->stk_bottom = ts->vaddr + REDZONE;
ts->stk_top = ts->stk_bottom + stack_size;
#ifdef DEBUG
mprotect(ts->vaddr, REDZONE, PROT_NONE);
mprotect(ts->stk_top + extra, REDZONE, PROT_NONE);
#endif
if (extra) {
long offset = (random() % extra) & ~0x7;
ts->stk_bottom += offset;
ts->stk_top += offset;
}
return ts;
}
/*
* Free the stack for the current thread
*/
void _st_stack_free(_st_stack_t *ts)
{
if (!ts)
return;
/* Put the stack on the free list */
ST_APPEND_LINK(&ts->links, _st_free_stacks.prev);
_st_num_free_stacks++;
}
static char *_st_new_stk_segment(int size)
{
#ifdef MALLOC_STACK
void *vaddr = malloc(size);
#else
static int zero_fd = -1;
int mmap_flags = MAP_PRIVATE;
void *vaddr;
#if defined (MD_USE_SYSV_ANON_MMAP)
if (zero_fd < 0) {
if ((zero_fd = open("/dev/zero", O_RDWR, 0)) < 0)
return NULL;
fcntl(zero_fd, F_SETFD, FD_CLOEXEC);
}
#elif defined (MD_USE_BSD_ANON_MMAP)
mmap_flags |= MAP_ANON;
#else
#error Unknown OS
#endif
vaddr = mmap(NULL, size, PROT_READ | PROT_WRITE, mmap_flags, zero_fd, 0);
if (vaddr == (void *)MAP_FAILED)
return NULL;
#endif /* MALLOC_STACK */
return (char *)vaddr;
}
/* Not used */
#if 0
void _st_delete_stk_segment(char *vaddr, int size)
{
#ifdef MALLOC_STACK
free(vaddr);
#else
(void) munmap(vaddr, size);
#endif
}
#endif
int st_randomize_stacks(int on)
{
int wason = _st_randomize_stacks;
_st_randomize_stacks = on;
if (on)
srandom((unsigned int) st_utime());
return wason;
}
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