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/* simulate `sbrk' with an array in .bss, for `unexec' support for Cygwin;
complete rewrite of xemacs Cygwin `unexec' code
Copyright (C) 2004-2020 Free Software Foundation, Inc.
This file is part of GNU Emacs.
GNU Emacs is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or (at
your option) any later version.
GNU Emacs 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>. */
#include <config.h>
#include "sheap.h"
#include <stdio.h>
#include "lisp.h"
#include <unistd.h>
#include <stdlib.h> /* for exit */
static int debug_sheap;
char bss_sbrk_buffer[STATIC_HEAP_SIZE];
char *max_bss_sbrk_ptr;
void *
bss_sbrk (ptrdiff_t request_size)
{
static char *bss_sbrk_ptr;
if (!bss_sbrk_ptr)
{
max_bss_sbrk_ptr = bss_sbrk_ptr = bss_sbrk_buffer;
#ifdef CYGWIN
/* Force space for fork to work. */
sbrk (4096);
#endif
}
int used = bss_sbrk_ptr - bss_sbrk_buffer;
if (request_size < -used)
{
printf (("attempt to free too much: "
"avail %d used %d failed request %"pD"d\n"),
STATIC_HEAP_SIZE, used, request_size);
exit (-1);
return 0;
}
else if (STATIC_HEAP_SIZE - used < request_size)
{
printf ("static heap exhausted: avail %d used %d failed request %"pD"d\n",
STATIC_HEAP_SIZE, used, request_size);
exit (-1);
return 0;
}
void *ret = bss_sbrk_ptr;
bss_sbrk_ptr += request_size;
if (max_bss_sbrk_ptr < bss_sbrk_ptr)
max_bss_sbrk_ptr = bss_sbrk_ptr;
if (debug_sheap)
{
if (request_size < 0)
printf ("freed size %"pD"d\n", request_size);
else
printf ("allocated %p size %"pD"d\n", ret, request_size);
}
return ret;
}
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