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/*
Copyright (C) 1995 Free Software Foundation, Inc.
Written by Michael I. Bushnell, p/BSG.
This file is part of the GNU Hurd.
The GNU Hurd 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.
The GNU Hurd 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., 59 Temple Place - Suite 330, Boston, MA 02111, USA. */
#include "netfs.h"
#include "io_S.h"
error_t
netfs_S_io_read (struct protid *user,
char **data,
mach_msg_type_number_t *datalen,
off_t offset,
mach_msg_type_number_t amount)
{
error_t err;
int alloced = 0;
if (!user)
return EOPNOTSUPP;
if (amount > *datalen)
{
alloced = 1;
vm_allocate (mach_task_self (), (vm_address_t *) data, amount, 1);
}
*datalen = amount;
mutex_lock (&user->po->np->lock);
err = netfs_attempt_read (user->credential, user->po->np,
offset == -1 ? user->po->filepointer : offset,
datalen, *data);
if (offset == -1 && !err)
user->po->filepointer += *datalen;
mutex_unlock (&user->po->np->lock);
if (err && alloced)
vm_deallocate (mach_task_self (), (vm_address_t) *data, amount);
if (!err && alloced && (round_page (*datalen) < round_page (amount)))
vm_deallocate (mach_task_self (),
(vm_address_t) *data + round_page (*datalen),
round_page (amount) - round_page (*datalen));
return err;
}
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