288 lines
7.2 KiB
C
288 lines
7.2 KiB
C
|
// SPDX-License-Identifier: GPL-2.0-only
|
||
|
|
/*
|
||
|
|
* Copyright (C) 2006-2009 Red Hat, Inc.
|
||
|
|
*
|
||
|
|
* This file is released under the LGPL.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include <linux/kernel.h>
|
||
|
|
#include <linux/module.h>
|
||
|
|
#include <linux/slab.h>
|
||
|
|
#include <net/sock.h>
|
||
|
|
#include <linux/workqueue.h>
|
||
|
|
#include <linux/connector.h>
|
||
|
|
#include <linux/device-mapper.h>
|
||
|
|
#include <linux/dm-log-userspace.h>
|
||
|
|
|
||
|
|
#include "dm-log-userspace-transfer.h"
|
||
|
|
|
||
|
|
static uint32_t dm_ulog_seq;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Netlink/Connector is an unreliable protocol. How long should
|
||
|
|
* we wait for a response before assuming it was lost and retrying?
|
||
|
|
* (If we do receive a response after this time, it will be discarded
|
||
|
|
* and the response to the resent request will be waited for.
|
||
|
|
*/
|
||
|
|
#define DM_ULOG_RETRY_TIMEOUT (15 * HZ)
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Pre-allocated space for speed
|
||
|
|
*/
|
||
|
|
#define DM_ULOG_PREALLOCED_SIZE 512
|
||
|
|
static struct cn_msg *prealloced_cn_msg;
|
||
|
|
static struct dm_ulog_request *prealloced_ulog_tfr;
|
||
|
|
|
||
|
|
static struct cb_id ulog_cn_id = {
|
||
|
|
.idx = CN_IDX_DM,
|
||
|
|
.val = CN_VAL_DM_USERSPACE_LOG
|
||
|
|
};
|
||
|
|
|
||
|
|
static DEFINE_MUTEX(dm_ulog_lock);
|
||
|
|
|
||
|
|
struct receiving_pkg {
|
||
|
|
struct list_head list;
|
||
|
|
struct completion complete;
|
||
|
|
|
||
|
|
uint32_t seq;
|
||
|
|
|
||
|
|
int error;
|
||
|
|
size_t *data_size;
|
||
|
|
char *data;
|
||
|
|
};
|
||
|
|
|
||
|
|
static DEFINE_SPINLOCK(receiving_list_lock);
|
||
|
|
static struct list_head receiving_list;
|
||
|
|
|
||
|
|
static int dm_ulog_sendto_server(struct dm_ulog_request *tfr)
|
||
|
|
{
|
||
|
|
int r;
|
||
|
|
struct cn_msg *msg = prealloced_cn_msg;
|
||
|
|
|
||
|
|
memset(msg, 0, sizeof(struct cn_msg));
|
||
|
|
|
||
|
|
msg->id.idx = ulog_cn_id.idx;
|
||
|
|
msg->id.val = ulog_cn_id.val;
|
||
|
|
msg->ack = 0;
|
||
|
|
msg->seq = tfr->seq;
|
||
|
|
msg->len = sizeof(struct dm_ulog_request) + tfr->data_size;
|
||
|
|
|
||
|
|
r = cn_netlink_send(msg, 0, 0, gfp_any());
|
||
|
|
|
||
|
|
return r;
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Parameters for this function can be either msg or tfr, but not
|
||
|
|
* both. This function fills in the reply for a waiting request.
|
||
|
|
* If just msg is given, then the reply is simply an ACK from userspace
|
||
|
|
* that the request was received.
|
||
|
|
*
|
||
|
|
* Returns: 0 on success, -ENOENT on failure
|
||
|
|
*/
|
||
|
|
static int fill_pkg(struct cn_msg *msg, struct dm_ulog_request *tfr)
|
||
|
|
{
|
||
|
|
uint32_t rtn_seq = (msg) ? msg->seq : (tfr) ? tfr->seq : 0;
|
||
|
|
struct receiving_pkg *pkg;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* The 'receiving_pkg' entries in this list are statically
|
||
|
|
* allocated on the stack in 'dm_consult_userspace'.
|
||
|
|
* Each process that is waiting for a reply from the user
|
||
|
|
* space server will have an entry in this list.
|
||
|
|
*
|
||
|
|
* We are safe to do it this way because the stack space
|
||
|
|
* is unique to each process, but still addressable by
|
||
|
|
* other processes.
|
||
|
|
*/
|
||
|
|
list_for_each_entry(pkg, &receiving_list, list) {
|
||
|
|
if (rtn_seq != pkg->seq)
|
||
|
|
continue;
|
||
|
|
|
||
|
|
if (msg) {
|
||
|
|
pkg->error = -msg->ack;
|
||
|
|
/*
|
||
|
|
* If we are trying again, we will need to know our
|
||
|
|
* storage capacity. Otherwise, along with the
|
||
|
|
* error code, we make explicit that we have no data.
|
||
|
|
*/
|
||
|
|
if (pkg->error != -EAGAIN)
|
||
|
|
*(pkg->data_size) = 0;
|
||
|
|
} else if (tfr->data_size > *(pkg->data_size)) {
|
||
|
|
DMERR("Insufficient space to receive package [%u] (%u vs %zu)",
|
||
|
|
tfr->request_type, tfr->data_size, *(pkg->data_size));
|
||
|
|
|
||
|
|
*(pkg->data_size) = 0;
|
||
|
|
pkg->error = -ENOSPC;
|
||
|
|
} else {
|
||
|
|
pkg->error = tfr->error;
|
||
|
|
memcpy(pkg->data, tfr->data, tfr->data_size);
|
||
|
|
*(pkg->data_size) = tfr->data_size;
|
||
|
|
}
|
||
|
|
complete(&pkg->complete);
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
return -ENOENT;
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* This is the connector callback that delivers data
|
||
|
|
* that was sent from userspace.
|
||
|
|
*/
|
||
|
|
static void cn_ulog_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
|
||
|
|
{
|
||
|
|
struct dm_ulog_request *tfr = (struct dm_ulog_request *)(msg + 1);
|
||
|
|
|
||
|
|
if (!capable(CAP_SYS_ADMIN))
|
||
|
|
return;
|
||
|
|
|
||
|
|
spin_lock(&receiving_list_lock);
|
||
|
|
if (msg->len == 0)
|
||
|
|
fill_pkg(msg, NULL);
|
||
|
|
else if (msg->len < sizeof(*tfr))
|
||
|
|
DMERR("Incomplete message received (expected %u, got %u): [%u]",
|
||
|
|
(unsigned int)sizeof(*tfr), msg->len, msg->seq);
|
||
|
|
else
|
||
|
|
fill_pkg(NULL, tfr);
|
||
|
|
spin_unlock(&receiving_list_lock);
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* dm_consult_userspace
|
||
|
|
* @uuid: log's universal unique identifier (must be DM_UUID_LEN in size)
|
||
|
|
* @luid: log's local unique identifier
|
||
|
|
* @request_type: found in include/linux/dm-log-userspace.h
|
||
|
|
* @data: data to tx to the server
|
||
|
|
* @data_size: size of data in bytes
|
||
|
|
* @rdata: place to put return data from server
|
||
|
|
* @rdata_size: value-result (amount of space given/amount of space used)
|
||
|
|
*
|
||
|
|
* rdata_size is undefined on failure.
|
||
|
|
*
|
||
|
|
* Memory used to communicate with userspace is zero'ed
|
||
|
|
* before populating to ensure that no unwanted bits leak
|
||
|
|
* from kernel space to user-space. All userspace log communications
|
||
|
|
* between kernel and user space go through this function.
|
||
|
|
*
|
||
|
|
* Returns: 0 on success, -EXXX on failure
|
||
|
|
**/
|
||
|
|
int dm_consult_userspace(const char *uuid, uint64_t luid, int request_type,
|
||
|
|
char *data, size_t data_size,
|
||
|
|
char *rdata, size_t *rdata_size)
|
||
|
|
{
|
||
|
|
int r = 0;
|
||
|
|
unsigned long tmo;
|
||
|
|
size_t dummy = 0;
|
||
|
|
int overhead_size = sizeof(struct dm_ulog_request) + sizeof(struct cn_msg);
|
||
|
|
struct dm_ulog_request *tfr = prealloced_ulog_tfr;
|
||
|
|
struct receiving_pkg pkg;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Given the space needed to hold the 'struct cn_msg' and
|
||
|
|
* 'struct dm_ulog_request' - do we have enough payload
|
||
|
|
* space remaining?
|
||
|
|
*/
|
||
|
|
if (data_size > (DM_ULOG_PREALLOCED_SIZE - overhead_size)) {
|
||
|
|
DMINFO("Size of tfr exceeds preallocated size");
|
||
|
|
return -EINVAL;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (!rdata_size)
|
||
|
|
rdata_size = &dummy;
|
||
|
|
resend:
|
||
|
|
/*
|
||
|
|
* We serialize the sending of requests so we can
|
||
|
|
* use the preallocated space.
|
||
|
|
*/
|
||
|
|
mutex_lock(&dm_ulog_lock);
|
||
|
|
|
||
|
|
memset(tfr, 0, DM_ULOG_PREALLOCED_SIZE - sizeof(struct cn_msg));
|
||
|
|
memcpy(tfr->uuid, uuid, DM_UUID_LEN);
|
||
|
|
tfr->version = DM_ULOG_REQUEST_VERSION;
|
||
|
|
tfr->luid = luid;
|
||
|
|
tfr->seq = dm_ulog_seq++;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Must be valid request type (all other bits set to
|
||
|
|
* zero). This reserves other bits for possible future
|
||
|
|
* use.
|
||
|
|
*/
|
||
|
|
tfr->request_type = request_type & DM_ULOG_REQUEST_MASK;
|
||
|
|
|
||
|
|
tfr->data_size = data_size;
|
||
|
|
if (data && data_size)
|
||
|
|
memcpy(tfr->data, data, data_size);
|
||
|
|
|
||
|
|
memset(&pkg, 0, sizeof(pkg));
|
||
|
|
init_completion(&pkg.complete);
|
||
|
|
pkg.seq = tfr->seq;
|
||
|
|
pkg.data_size = rdata_size;
|
||
|
|
pkg.data = rdata;
|
||
|
|
spin_lock(&receiving_list_lock);
|
||
|
|
list_add(&(pkg.list), &receiving_list);
|
||
|
|
spin_unlock(&receiving_list_lock);
|
||
|
|
|
||
|
|
r = dm_ulog_sendto_server(tfr);
|
||
|
|
|
||
|
|
mutex_unlock(&dm_ulog_lock);
|
||
|
|
|
||
|
|
if (r) {
|
||
|
|
DMERR("Unable to send log request [%u] to userspace: %d",
|
||
|
|
request_type, r);
|
||
|
|
spin_lock(&receiving_list_lock);
|
||
|
|
list_del_init(&(pkg.list));
|
||
|
|
spin_unlock(&receiving_list_lock);
|
||
|
|
|
||
|
|
goto out;
|
||
|
|
}
|
||
|
|
|
||
|
|
tmo = wait_for_completion_timeout(&(pkg.complete), DM_ULOG_RETRY_TIMEOUT);
|
||
|
|
spin_lock(&receiving_list_lock);
|
||
|
|
list_del_init(&(pkg.list));
|
||
|
|
spin_unlock(&receiving_list_lock);
|
||
|
|
if (!tmo) {
|
||
|
|
DMWARN("[%s] Request timed out: [%u/%u] - retrying",
|
||
|
|
(strlen(uuid) > 8) ?
|
||
|
|
(uuid + (strlen(uuid) - 8)) : (uuid),
|
||
|
|
request_type, pkg.seq);
|
||
|
|
goto resend;
|
||
|
|
}
|
||
|
|
|
||
|
|
r = pkg.error;
|
||
|
|
if (r == -EAGAIN)
|
||
|
|
goto resend;
|
||
|
|
|
||
|
|
out:
|
||
|
|
return r;
|
||
|
|
}
|
||
|
|
|
||
|
|
int dm_ulog_tfr_init(void)
|
||
|
|
{
|
||
|
|
int r;
|
||
|
|
void *prealloced;
|
||
|
|
|
||
|
|
INIT_LIST_HEAD(&receiving_list);
|
||
|
|
|
||
|
|
prealloced = kmalloc(DM_ULOG_PREALLOCED_SIZE, GFP_KERNEL);
|
||
|
|
if (!prealloced)
|
||
|
|
return -ENOMEM;
|
||
|
|
|
||
|
|
prealloced_cn_msg = prealloced;
|
||
|
|
prealloced_ulog_tfr = prealloced + sizeof(struct cn_msg);
|
||
|
|
|
||
|
|
r = cn_add_callback(&ulog_cn_id, "dmlogusr", cn_ulog_callback);
|
||
|
|
if (r) {
|
||
|
|
kfree(prealloced_cn_msg);
|
||
|
|
return r;
|
||
|
|
}
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
void dm_ulog_tfr_exit(void)
|
||
|
|
{
|
||
|
|
cn_del_callback(&ulog_cn_id);
|
||
|
|
kfree(prealloced_cn_msg);
|
||
|
|
}
|