1999-04-16 01:35:26 +00:00
|
|
|
/* Support for sbrk() regions.
|
2000-02-18 01:39:02 +00:00
|
|
|
Copyright 1992, 2000 Free Software Foundation, Inc.
|
1999-04-16 01:35:26 +00:00
|
|
|
Contributed by Fred Fish at Cygnus Support. fnf@cygnus.com
|
|
|
|
|
|
|
|
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., 59 Temple Place - Suite 330,
|
|
|
|
Boston, MA 02111-1307, USA. */
|
|
|
|
|
2000-02-18 01:39:02 +00:00
|
|
|
#ifdef HAVE_UNISTD_H
|
|
|
|
#include <unistd.h> /* Prototypes for sbrk (maybe) */
|
|
|
|
#endif
|
1999-04-16 01:35:26 +00:00
|
|
|
#include <string.h> /* Prototypes for memcpy, memmove, memset, etc */
|
|
|
|
|
|
|
|
#include "mmprivate.h"
|
|
|
|
|
|
|
|
static PTR sbrk_morecore PARAMS ((struct mdesc *, int));
|
2000-02-05 07:30:26 +00:00
|
|
|
#if NEED_DECLARATION_SBRK
|
1999-04-16 01:35:26 +00:00
|
|
|
extern PTR sbrk PARAMS ((int));
|
2000-02-05 07:30:26 +00:00
|
|
|
#endif
|
1999-04-16 01:35:26 +00:00
|
|
|
|
|
|
|
/* The mmalloc() package can use a single implicit malloc descriptor
|
|
|
|
for mmalloc/mrealloc/mfree operations which do not supply an explicit
|
|
|
|
descriptor. For these operations, sbrk() is used to obtain more core
|
|
|
|
from the system, or return core. This allows mmalloc() to provide
|
|
|
|
backwards compatibility with the non-mmap'd version. */
|
|
|
|
|
|
|
|
struct mdesc *__mmalloc_default_mdp;
|
|
|
|
|
|
|
|
/* Use sbrk() to get more core. */
|
|
|
|
|
|
|
|
static PTR
|
|
|
|
sbrk_morecore (mdp, size)
|
|
|
|
struct mdesc *mdp;
|
|
|
|
int size;
|
|
|
|
{
|
|
|
|
PTR result;
|
|
|
|
|
|
|
|
if ((result = sbrk (size)) == (PTR) -1)
|
|
|
|
{
|
|
|
|
result = NULL;
|
|
|
|
}
|
|
|
|
else
|
|
|
|
{
|
|
|
|
mdp -> breakval += size;
|
|
|
|
mdp -> top += size;
|
|
|
|
}
|
|
|
|
return (result);
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Initialize the default malloc descriptor if this is the first time
|
|
|
|
a request has been made to use the default sbrk'd region.
|
|
|
|
|
|
|
|
Since no alignment guarantees are made about the initial value returned
|
|
|
|
by sbrk, test the initial value and (if necessary) sbrk enough additional
|
|
|
|
memory to start off with alignment to BLOCKSIZE. We actually only need
|
|
|
|
it aligned to an alignment suitable for any object, so this is overkill.
|
|
|
|
But at most it wastes just part of one BLOCKSIZE chunk of memory and
|
|
|
|
minimizes portability problems by avoiding us having to figure out
|
|
|
|
what the actual minimal alignment is. The rest of the malloc code
|
|
|
|
avoids this as well, by always aligning to the minimum of the requested
|
|
|
|
size rounded up to a power of two, or to BLOCKSIZE.
|
|
|
|
|
|
|
|
Note that we are going to use some memory starting at this initial sbrk
|
|
|
|
address for the sbrk region malloc descriptor, which is a struct, so the
|
|
|
|
base address must be suitably aligned. */
|
|
|
|
|
|
|
|
struct mdesc *
|
|
|
|
__mmalloc_sbrk_init ()
|
|
|
|
{
|
|
|
|
PTR base;
|
|
|
|
unsigned int adj;
|
|
|
|
|
|
|
|
base = sbrk (0);
|
|
|
|
adj = RESIDUAL (base, BLOCKSIZE);
|
|
|
|
if (adj != 0)
|
|
|
|
{
|
|
|
|
sbrk (BLOCKSIZE - adj);
|
|
|
|
base = sbrk (0);
|
|
|
|
}
|
|
|
|
__mmalloc_default_mdp = (struct mdesc *) sbrk (sizeof (struct mdesc));
|
|
|
|
memset ((char *) __mmalloc_default_mdp, 0, sizeof (struct mdesc));
|
|
|
|
__mmalloc_default_mdp -> morecore = sbrk_morecore;
|
|
|
|
__mmalloc_default_mdp -> base = base;
|
|
|
|
__mmalloc_default_mdp -> breakval = __mmalloc_default_mdp -> top = sbrk (0);
|
|
|
|
__mmalloc_default_mdp -> fd = -1;
|
|
|
|
return (__mmalloc_default_mdp);
|
|
|
|
}
|
|
|
|
|
|
|
|
|