80 lines
2.1 KiB
C
80 lines
2.1 KiB
C
/* simulate `sbrk' with an array in .bss, for `unexec' support for Cygwin;
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complete rewrite of xemacs Cygwin `unexec' code
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Copyright (C) 2004-2024 Free Software Foundation, Inc.
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This file is part of GNU Emacs.
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GNU Emacs is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or (at
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your option) any later version.
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GNU Emacs 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
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>. */
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#include <config.h>
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#include "sheap.h"
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#include <stdio.h>
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#include "lisp.h"
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#include <unistd.h>
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#include <stdlib.h> /* for exit */
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static int debug_sheap;
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char bss_sbrk_buffer[STATIC_HEAP_SIZE];
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char *max_bss_sbrk_ptr;
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void *
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bss_sbrk (ptrdiff_t request_size)
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{
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static char *bss_sbrk_ptr;
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if (!bss_sbrk_ptr)
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{
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max_bss_sbrk_ptr = bss_sbrk_ptr = bss_sbrk_buffer;
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#ifdef CYGWIN
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/* Force space for fork to work. */
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sbrk (4096);
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#endif
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}
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int used = bss_sbrk_ptr - bss_sbrk_buffer;
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if (request_size < -used)
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{
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printf (("attempt to free too much: "
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"avail %d used %d failed request %"pD"d\n"),
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STATIC_HEAP_SIZE, used, request_size);
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exit (-1);
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return 0;
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}
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else if (STATIC_HEAP_SIZE - used < request_size)
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{
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printf ("static heap exhausted: avail %d used %d failed request %"pD"d\n",
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STATIC_HEAP_SIZE, used, request_size);
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exit (-1);
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return 0;
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}
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void *ret = bss_sbrk_ptr;
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bss_sbrk_ptr += request_size;
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if (max_bss_sbrk_ptr < bss_sbrk_ptr)
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max_bss_sbrk_ptr = bss_sbrk_ptr;
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if (debug_sheap)
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{
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if (request_size < 0)
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printf ("freed size %"pD"d\n", request_size);
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else
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printf ("allocated %p size %"pD"d\n", ret, request_size);
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}
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return ret;
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}
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