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/* libguestfs - the guestfsd daemon
* Copyright (C) 2012 Red Hat Inc.
*
* 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <time.h>
#include "guestfs_protocol.h"
#include "daemon.h"
#include "actions.h"
#define HOT_ADD_TIMEOUT 30 /* seconds */
#define HOT_REMOVE_TIMEOUT HOT_ADD_TIMEOUT
static void
hotplug_error (const char *op, const char *path, const char *verb,
int timeout)
{
reply_with_error ("%s drive: '%s' did not %s after %d seconds: "
"this could mean that virtio-scsi (in qemu or kernel) "
"or udev is not working",
op, path, verb, timeout);
}
/* Wait for /dev/disk/guestfs/<label> to appear. Timeout (and error)
* if it doesn't appear after a reasonable length of time.
*/
int
do_internal_hot_add_drive (const char *label)
{
time_t start_t, now_t;
size_t len = strlen (label);
char path[len+64];
int r;
snprintf (path, len+64, "/dev/disk/guestfs/%s", label);
time (&start_t);
while (time (&now_t) - start_t <= HOT_ADD_TIMEOUT) {
udev_settle ();
r = access (path, F_OK);
if (r == -1 && errno != ENOENT) {
reply_with_perror ("%s", path);
return -1;
}
if (r == 0)
return 0;
sleep (1);
}
hotplug_error ("hot-add", path, "appear", HOT_ADD_TIMEOUT);
return -1;
}
GUESTFSD_EXT_CMD(str_fuser, fuser);
/* This function is called before a drive is hot-unplugged. */
int
do_internal_hot_remove_drive_precheck (const char *label)
{
size_t len = strlen (label);
char path[len+64];
int r;
char *out, *err;
/* Ensure there are no requests in flight (thanks Paolo Bonzini). */
udev_settle ();
sync_disks ();
snprintf (path, len+64, "/dev/disk/guestfs/%s", label);
r = commandr (&out, &err, str_fuser, "-v", "-m", path, NULL);
if (r == -1) {
reply_with_error ("fuser: %s: %s", path, err);
free (out);
free (err);
return -1;
}
free (err);
/* "fuser returns a non-zero return code if none of the specified
* files is accessed or in case of a fatal error. If at least one
* access has been found, fuser returns zero."
*/
if (r == 0) {
reply_with_error ("disk with label '%s' is in use "
"(eg. mounted or belongs to a volume group)", label);
/* Useful for debugging when a drive cannot be unplugged. */
if (verbose)
fprintf (stderr, "%s\n", out);
free (out);
return -1;
}
free (out);
return 0;
}
/* This function is called after a drive is hot-unplugged. It checks
* that it has really gone and udev has finished processing the
* events, in case the user immediately hotplugs a drive with an
* identical label.
*/
int
do_internal_hot_remove_drive (const char *label)
{
time_t start_t, now_t;
size_t len = strlen (label);
char path[len+64];
int r;
snprintf (path, len+64, "/dev/disk/guestfs/%s", label);
time (&start_t);
while (time (&now_t) - start_t <= HOT_REMOVE_TIMEOUT) {
udev_settle ();
r = access (path, F_OK);
if (r == -1) {
if (errno != ENOENT) {
reply_with_perror ("%s", path);
return -1;
}
/* else udev has removed the file, so we can return */
return 0;
}
sleep (1);
}
hotplug_error ("hot-remove", path, "disappear", HOT_REMOVE_TIMEOUT);
return -1;
}
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