72 lines
2.0 KiB
C
72 lines
2.0 KiB
C
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/* Finish access to a mmap'd malloc managed region.
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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 program 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 2 of the License, or
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(at your option) any later version.
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This program 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 this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
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#include <fcntl.h>
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#include "mmalloc.h"
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/* Terminate access to a mmalloc managed region by unmapping all memory pages
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associated with the region, and closing the file descriptor if it is one
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that we opened.
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Returns NULL on success.
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Returns the malloc descriptor on failure, which can subsequently be used
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for further action, such as obtaining more information about the nature of
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the failure by examining the preserved errno value.
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Note that the malloc descriptor that we are using is currently located in
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region we are about to unmap, so we first make a local copy of it on the
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stack and use the copy. */
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PTR
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mmalloc_detach (md)
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void *md;
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{
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struct mdesc mtemp;
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if (md != NULL)
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{
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mtemp = *(struct mdesc *) md;
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/* Now unmap all the pages associated with this region by asking for a
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negative increment equal to the current size of the region. */
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if ((mtemp.morecore (&mtemp, mtemp.base - mtemp.top)) == NULL)
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{
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/* Update the original malloc descriptor with any changes */
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*(struct mdesc *) md = mtemp;
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}
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else
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{
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if (mtemp.flags & MMALLOC_DEVZERO)
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{
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(void) close (mtemp.fd);
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}
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md = NULL;
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}
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}
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return (md);
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}
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