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/* Get the mach device underlying a file
Copyright (C) 1995, 1996 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 <errno.h>
#include <sys/fcntl.h>
#include <device/device.h>
#include "priv.h"
/* Returns the name and a send right for the mach device on which the file
NAME is stored, and returns it in DEV_NAME (which is malloced) and PORT.
Other values returned are START, the first valid offset, SIZE, the the
number of blocks after START, and BLOCK_SIZE, the units in which the
device is addressed.
The device is opened for reading, and if the diskfs global variable
DISKFS_READONLY is false, writing. */
error_t
diskfs_get_file_device (char *name,
char **dev_name, mach_port_t *port,
off_t *start, off_t *size, size_t *block_size)
{
int i;
error_t err;
mach_msg_type_number_t data_len = 100;
mach_msg_type_number_t num_ints = 10, num_ports = 10, num_offsets = 10;
int _ints[num_ints], *ints = _ints;
mach_port_t _ports[num_ports], *ports = _ports;
off_t _offsets[num_offsets], *offsets = _offsets;
char _data[data_len], *data = _data;
file_t node =
file_name_lookup (name, diskfs_readonly ? O_RDONLY : O_RDWR, 0);
if (node == MACH_PORT_NULL)
return errno;
*port = MACH_PORT_NULL;
err = file_get_storage_info (node, &ports, &num_ports, &ints, &num_ints,
&offsets, &num_offsets, &data, &data_len);
if (err)
return err;
/* See <hurd/store.h> for an explanation of what's in the vectors returned
by file_get_storage_info. */
if (num_ints < 6)
err = EGRATUITOUS;
else if (ints[0] != STORAGE_DEVICE)
err = ENODEV;
if (!err && block_size)
*block_size = ints[2];
if (!err && (start || size))
/* Extract the device block addresses. */
{
size_t num_runs = ints[3];
if (num_runs != 1)
/* We can't handle anything but a contiguous set of blocks. */
err = ENODEV; /* XXX */
else
{
if (start)
*start = offsets[0];
if (size)
*size = offsets[1];
}
}
if (!err && dev_name)
/* Extract the device name into DEV_NAME. */
{
size_t name_len = ints[4];
if (data && name_len > 0)
if (data_len < name_len)
err = EGRATUITOUS;
else
{
*dev_name = malloc (name_len);
if (*dev_name)
strcpy (*dev_name, data);
else
err = ENOMEM;
}
}
if (!err && port)
/* Extract the device port. */
if (num_ports != 1)
err = EGRATUITOUS;
else
*port = ports[0];
/* Deallocate things we don't care about or that we've made copies of. */
for (i = (err || !port) ? 0 : 1; i < num_ports; i++)
if (MACH_PORT_VALID (ports[i]))
mach_port_deallocate (mach_task_self (), ports[i]);
#define DISCARD_MEM(v, vl, b) \
if (v != b) \
vm_deallocate (mach_task_self (), (vm_address_t)v, vl * sizeof *v);
DISCARD_MEM (ports, num_ports, _ports);
DISCARD_MEM (ints, num_ints, _ints);
DISCARD_MEM (offsets, num_offsets, _offsets);
DISCARD_MEM (data, data_len, _data);
/* Note that we don't deallocate NODE unless we're returning an error,
which should prevent the information returned by file_get_storage_info
from changing. */
if (err)
/* We got an error, deallocate everything. */
mach_port_deallocate (mach_task_self (), node);
return err;
}
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