/* Finish access to a mmap'd malloc managed region. Copyright 1992 Free Software Foundation, Inc. Contributed by Fred Fish at Cygnus Support. fnf@cygnus.com This program 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 2 of the License, or (at your option) any later version. This program 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 this program; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include <fcntl.h> #include "mmalloc.h" /* Terminate access to a mmalloc managed region by unmapping all memory pages associated with the region, and closing the file descriptor if it is one that we opened. Returns NULL on success. Returns the malloc descriptor on failure, which can subsequently be used for further action, such as obtaining more information about the nature of the failure by examining the preserved errno value. Note that the malloc descriptor that we are using is currently located in region we are about to unmap, so we first make a local copy of it on the stack and use the copy. */ PTR mmalloc_detach (md) void *md; { struct mdesc mtemp; if (md != NULL) { mtemp = *(struct mdesc *) md; /* Now unmap all the pages associated with this region by asking for a negative increment equal to the current size of the region. */ if ((mtemp.morecore (&mtemp, mtemp.base - mtemp.top)) == NULL) { /* Update the original malloc descriptor with any changes */ *(struct mdesc *) md = mtemp; } else { if (mtemp.flags & MMALLOC_DEVZERO) { (void) close (mtemp.fd); } md = NULL; } } return (md); }