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/*
* Copyright (C) 2011
* Author Roger Pau Monne <roger.pau@entel.upc.edu>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation; version 2.1 only. with the special
* exception on linking described in file LICENSE.
*
* 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 Lesser General Public License for more details.
*/
#include "libxl_osdeps.h" /* must come before any other headers */
#include "libxl_internal.h"
int libxl__try_phy_backend(mode_t st_mode)
{
if (!S_ISBLK(st_mode)) {
return 0;
}
return 1;
}
#define EXT_SHIFT 28
#define EXTENDED (1<<EXT_SHIFT)
#define VDEV_IS_EXTENDED(dev) ((dev)&(EXTENDED))
#define BLKIF_MINOR_EXT(dev) ((dev)&(~EXTENDED))
/* the size of the buffer to store the device name is 32 bytes to match the
* equivalent buffer in the Linux kernel code */
#define BUFFER_SIZE 32
/* Same as in Linux.
* encode_disk_name might end up using up to 29 bytes (BUFFER_SIZE - 3)
* including the trailing \0.
*
* The code is safe because 26 raised to the power of 28 (that is the
* maximum offset that can be stored in the allocated buffer as a
* string) is far greater than UINT_MAX on 64 bits so offset cannot be
* big enough to exhaust the available bytes in ret. */
static char *encode_disk_name(char *ptr, unsigned int n)
{
if (n >= 26)
ptr = encode_disk_name(ptr, n / 26 - 1);
*ptr = 'a' + n % 26;
return ptr + 1;
}
char *libxl__devid_to_localdev(libxl__gc *gc, int devid)
{
unsigned int minor;
int offset;
int nr_parts;
char *ptr = NULL;
char *ret = libxl__zalloc(gc, BUFFER_SIZE);
if (!VDEV_IS_EXTENDED(devid)) {
minor = devid & 0xff;
nr_parts = 16;
} else {
minor = BLKIF_MINOR_EXT(devid);
nr_parts = 256;
}
offset = minor / nr_parts;
strcpy(ret, "xvd");
ptr = encode_disk_name(ret + 3, offset);
if (minor % nr_parts == 0)
*ptr = 0;
else
/* overflow cannot happen, thanks to the upper bound */
snprintf(ptr, ret + 32 - ptr,
"%d", minor & (nr_parts - 1));
return ret;
}
/* Hotplug scripts helpers */
static char **get_hotplug_env(libxl__gc *gc, libxl__device *dev)
{
char *be_path = libxl__device_backend_path(gc, dev);
char *script;
const char *type = libxl__device_kind_to_string(dev->backend_kind);
char **env;
int nr = 0;
script = libxl__xs_read(gc, XBT_NULL,
GCSPRINTF("%s/%s", be_path, "script"));
if (!script) {
LOGEV(ERROR, errno, "unable to read script from %s", be_path);
return NULL;
}
const int arraysize = 9;
GCNEW_ARRAY(env, arraysize);
env[nr++] = "script";
env[nr++] = script;
env[nr++] = "XENBUS_TYPE";
env[nr++] = libxl__strdup(gc, type);
env[nr++] = "XENBUS_PATH";
env[nr++] = GCSPRINTF("backend/%s/%u/%d", type, dev->domid, dev->devid);
env[nr++] = "XENBUS_BASE_PATH";
env[nr++] = "backend";
env[nr++] = NULL;
assert(nr == arraysize);
return env;
}
/* Hotplug scripts caller functions */
static int libxl__hotplug_disk(libxl__gc *gc, libxl__device *dev,
char ***args, char ***env,
libxl__device_action action)
{
char *be_path = libxl__device_backend_path(gc, dev);
char *script;
int nr = 0, rc = 0;
script = libxl__xs_read(gc, XBT_NULL,
GCSPRINTF("%s/%s", be_path, "script"));
if (!script) {
LOGEV(ERROR, errno, "unable to read script from %s", be_path);
rc = ERROR_FAIL;
goto error;
}
*env = get_hotplug_env(gc, dev);
if (!*env) {
rc = ERROR_FAIL;
goto error;
}
const int arraysize = 3;
GCNEW_ARRAY(*args, arraysize);
(*args)[nr++] = script;
(*args)[nr++] = action == DEVICE_CONNECT ? "add" : "remove";
(*args)[nr++] = NULL;
assert(nr == arraysize);
rc = 1;
error:
return rc;
}
int libxl__get_hotplug_script_info(libxl__gc *gc, libxl__device *dev,
char ***args, char ***env,
libxl__device_action action)
{
char *disable_udev = libxl__xs_read(gc, XBT_NULL, DISABLE_UDEV_PATH);
int rc;
/* Check if we have to run hotplug scripts */
if (!disable_udev) {
rc = 0;
goto out;
}
switch (dev->backend_kind) {
case LIBXL__DEVICE_KIND_VBD:
rc = libxl__hotplug_disk(gc, dev, args, env, action);
break;
default:
/* No need to execute any hotplug scripts */
rc = 0;
break;
}
out:
return rc;
}
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