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/* Some random handy ops for dealing with rpcs that return memory.
Copyright (C) 1995 Free Software Foundation, Inc.
Written by Miles Bader <miles@gnu.ai.mit.edu>
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, 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 <hurd.h>
#include <string.h>
/* ---------------------------------------------------------------- */
/* Makes sure that BUF, points to a buffer with AMOUNT bytes available.
*BUF_LEN should be the current length of *BUF, and if this isn't enough to
hold AMOUNT bytes, then more is allocated and the new buffer is returned
in *BUF and *BUF_LEN. If a memory allocation error occurs, the error code
is returned, otherwise 0. */
error_t
allocate(vm_address_t *buf, vm_size_t *buf_len, vm_size_t amount)
{
if (*buf_len < amount)
{
error_t err = vm_allocate(mach_task_self(), buf, amount, 1);
if (err)
return err;
}
*buf_len = amount;
return 0;
}
/* Deallocates any pages entirely within the last EXCESS bytes of the BUF_LEN
long buffer, BUF. */
error_t
deallocate_excess(vm_address_t buf, vm_size_t buf_len, vm_size_t excess)
{
vm_size_t excess_pages = buf_len - round_page(buf_len - excess);
if (excess_pages > 0)
return
vm_deallocate(mach_task_self(),
round_page(buf + buf_len - excess), excess_pages);
else
return 0;
}
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