72 lines
2.2 KiB
C
72 lines
2.2 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 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., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include <sys/types.h>
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#include "mmprivate.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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PTR 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.breakval)) == NULL)
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{
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/* Deallocating failed. Update the original malloc descriptor
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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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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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