| 1 | /* Finish access to a mmap'd malloc managed region. |
| 2 | Copyright 1992 Free Software Foundation, Inc. |
| 3 | |
| 4 | Contributed by Fred Fish at Cygnus Support. fnf@cygnus.com |
| 5 | |
| 6 | This file is part of the GNU C Library. |
| 7 | |
| 8 | The GNU C Library is free software; you can redistribute it and/or |
| 9 | modify it under the terms of the GNU Library General Public License as |
| 10 | published by the Free Software Foundation; either version 2 of the |
| 11 | License, or (at your option) any later version. |
| 12 | |
| 13 | The GNU C Library is distributed in the hope that it will be useful, |
| 14 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 16 | Library General Public License for more details. |
| 17 | |
| 18 | You should have received a copy of the GNU Library General Public |
| 19 | License along with the GNU C Library; see the file COPYING.LIB. If |
| 20 | not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
| 21 | Boston, MA 02111-1307, USA. */ |
| 22 | |
| 23 | #include <sys/types.h> |
| 24 | #include "mmprivate.h" |
| 25 | |
| 26 | /* Terminate access to a mmalloc managed region by unmapping all memory pages |
| 27 | associated with the region, and closing the file descriptor if it is one |
| 28 | that we opened. |
| 29 | |
| 30 | Returns NULL on success. |
| 31 | |
| 32 | Returns the malloc descriptor on failure, which can subsequently be used |
| 33 | for further action, such as obtaining more information about the nature of |
| 34 | the failure by examining the preserved errno value. |
| 35 | |
| 36 | Note that the malloc descriptor that we are using is currently located in |
| 37 | region we are about to unmap, so we first make a local copy of it on the |
| 38 | stack and use the copy. */ |
| 39 | |
| 40 | PTR |
| 41 | mmalloc_detach (md) |
| 42 | PTR md; |
| 43 | { |
| 44 | struct mdesc mtemp; |
| 45 | |
| 46 | if (md != NULL) |
| 47 | { |
| 48 | |
| 49 | mtemp = *(struct mdesc *) md; |
| 50 | |
| 51 | /* Now unmap all the pages associated with this region by asking for a |
| 52 | negative increment equal to the current size of the region. */ |
| 53 | |
| 54 | if ((mtemp.morecore (&mtemp, mtemp.base - mtemp.breakval)) == NULL) |
| 55 | { |
| 56 | /* Deallocating failed. Update the original malloc descriptor |
| 57 | with any changes */ |
| 58 | *(struct mdesc *) md = mtemp; |
| 59 | } |
| 60 | else |
| 61 | { |
| 62 | if (mtemp.flags & MMALLOC_DEVZERO) |
| 63 | { |
| 64 | close (mtemp.fd); |
| 65 | } |
| 66 | md = NULL; |
| 67 | } |
| 68 | } |
| 69 | |
| 70 | return (md); |
| 71 | } |