38cc378c61
This is a greatly pared down version of the full gdb-4.12, all the config stuff has been removed and the supporting libraries have been stripped to a minimum. This is a 1.1.5 only port, I'll do a more complete port for 2.0 which will have all the config stuff and will install the gnu support libraries as system libraries like we do for readline. There wasn't much point for 1.1.5 since only gdb would use them so I went for saving space instead. For 2.0 I'll config all the other gnu tools to use them as well.
97 lines
3.2 KiB
C
97 lines
3.2 KiB
C
/* Support for sbrk() regions.
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Copyright 1992 Free Software Foundation, Inc.
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Contributed by Fred Fish at Cygnus Support. fnf@cygnus.com
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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 <string.h> /* Prototypes for memcpy, memmove, memset, etc */
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#include "mmalloc.h"
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extern PTR sbrk ();
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/* The mmalloc() package can use a single implicit malloc descriptor
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for mmalloc/mrealloc/mfree operations which do not supply an explicit
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descriptor. For these operations, sbrk() is used to obtain more core
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from the system, or return core. This allows mmalloc() to provide
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backwards compatibility with the non-mmap'd version. */
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struct mdesc *__mmalloc_default_mdp;
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/* Use sbrk() to get more core. */
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static PTR
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sbrk_morecore (mdp, size)
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struct mdesc *mdp;
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int size;
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{
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PTR result;
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if ((result = sbrk (size)) == (PTR) -1)
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{
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result = NULL;
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}
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else
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{
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mdp -> breakval += size;
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mdp -> top += size;
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}
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return (result);
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}
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/* Initialize the default malloc descriptor if this is the first time
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a request has been made to use the default sbrk'd region.
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Since no alignment guarantees are made about the initial value returned
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by sbrk, test the initial value and (if necessary) sbrk enough additional
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memory to start off with alignment to BLOCKSIZE. We actually only need
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it aligned to an alignment suitable for any object, so this is overkill.
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But at most it wastes just part of one BLOCKSIZE chunk of memory and
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minimizes portability problems by avoiding us having to figure out
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what the actual minimal alignment is. The rest of the malloc code
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avoids this as well, by always aligning to the minimum of the requested
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size rounded up to a power of two, or to BLOCKSIZE.
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Note that we are going to use some memory starting at this initial sbrk
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address for the sbrk region malloc descriptor, which is a struct, so the
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base address must be suitably aligned. */
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struct mdesc *
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__mmalloc_sbrk_init ()
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{
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PTR base;
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unsigned int adj;
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base = sbrk (0);
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adj = RESIDUAL (base, BLOCKSIZE);
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if (adj != 0)
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{
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sbrk (BLOCKSIZE - adj);
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base = sbrk (0);
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}
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__mmalloc_default_mdp = (struct mdesc *) sbrk (sizeof (struct mdesc));
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memset ((char *) __mmalloc_default_mdp, 0, sizeof (struct mdesc));
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__mmalloc_default_mdp -> morecore = sbrk_morecore;
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__mmalloc_default_mdp -> base = base;
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__mmalloc_default_mdp -> breakval = __mmalloc_default_mdp -> top = sbrk (0);
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__mmalloc_default_mdp -> fd = -1;
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return (__mmalloc_default_mdp);
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}
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