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/* Get the mach device underlying a file
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 <errno.h>
#include <sys/fcntl.h>
#include <device/device.h>
#include "priv.h"
typedef int run_elem_t;
/* 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)
{
error_t err;
int class, flags;
char *misc = 0;
off_t *runs = 0;
mach_msg_type_number_t misc_len = 0, runs_len = 0;
string_t dev_name_buf;
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, &class, &runs, &runs_len, block_size,
dev_name_buf, port, &misc, &misc_len, &flags);
if (err)
goto done;
if (class != STORAGE_DEVICE)
{
err = ENODEV;
goto done;
}
if (dev_name)
{
*dev_name = malloc (strlen (dev_name_buf) + 1);
if (*dev_name)
strcpy (*dev_name, dev_name_buf);
else
err = ENOMEM;
}
if (start || size)
if (runs_len > 2)
/* We can't handle anything but a contiguous set of blocks. */
err = ENODEV; /* XXX */
else
{
if (start)
*start = runs[0];
if (size)
*size = runs[1];
}
/* Note that we don't deallocate NODE, which should prevent the information
returned by file_get_storage_info from changing. */
done:
if (err)
{
mach_port_deallocate (mach_task_self (), node);
if (*port)
mach_port_deallocate (mach_task_self (), *port);
}
if (misc_len > 0)
vm_deallocate (mach_task_self (), (vm_address_t)misc, misc_len);
if (runs_len > 0)
vm_deallocate (mach_task_self (),
(vm_address_t)runs, runs_len * sizeof (*runs));
return err;
}
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