mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-14 15:46:43 +07:00
31998ef193
Device mapper uses sscanf to convert arguments to numbers. The problem is that the way we use it ignores additional unmatched characters in the scanned string. For example, this `if (sscanf(string, "%d", &number) == 1)' will match a number, but also it will match number with some garbage appended, like "123abc". As a result, device mapper accepts garbage after some numbers. For example the command `dmsetup create vg1-new --table "0 16384 linear 254:1bla 34816bla"' will pass without an error. This patch fixes all sscanf uses in device mapper. It appends "%c" with a pointer to a dummy character variable to every sscanf statement. The construct `if (sscanf(string, "%d%c", &number, &dummy) == 1)' succeeds only if string is a null-terminated number (optionally preceded by some whitespace characters). If there is some character appended after the number, sscanf matches "%c", writes the character to the dummy variable and returns 2. We check the return value for 1 and consequently reject numbers with some garbage appended. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Acked-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
220 lines
4.6 KiB
C
220 lines
4.6 KiB
C
/*
|
|
* Copyright (C) 2003 Sistina Software.
|
|
* Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved.
|
|
*
|
|
* Module Author: Heinz Mauelshagen
|
|
*
|
|
* This file is released under the GPL.
|
|
*
|
|
* Round-robin path selector.
|
|
*/
|
|
|
|
#include <linux/device-mapper.h>
|
|
|
|
#include "dm-path-selector.h"
|
|
|
|
#include <linux/slab.h>
|
|
#include <linux/module.h>
|
|
|
|
#define DM_MSG_PREFIX "multipath round-robin"
|
|
|
|
/*-----------------------------------------------------------------
|
|
* Path-handling code, paths are held in lists
|
|
*---------------------------------------------------------------*/
|
|
struct path_info {
|
|
struct list_head list;
|
|
struct dm_path *path;
|
|
unsigned repeat_count;
|
|
};
|
|
|
|
static void free_paths(struct list_head *paths)
|
|
{
|
|
struct path_info *pi, *next;
|
|
|
|
list_for_each_entry_safe(pi, next, paths, list) {
|
|
list_del(&pi->list);
|
|
kfree(pi);
|
|
}
|
|
}
|
|
|
|
/*-----------------------------------------------------------------
|
|
* Round-robin selector
|
|
*---------------------------------------------------------------*/
|
|
|
|
#define RR_MIN_IO 1000
|
|
|
|
struct selector {
|
|
struct list_head valid_paths;
|
|
struct list_head invalid_paths;
|
|
};
|
|
|
|
static struct selector *alloc_selector(void)
|
|
{
|
|
struct selector *s = kmalloc(sizeof(*s), GFP_KERNEL);
|
|
|
|
if (s) {
|
|
INIT_LIST_HEAD(&s->valid_paths);
|
|
INIT_LIST_HEAD(&s->invalid_paths);
|
|
}
|
|
|
|
return s;
|
|
}
|
|
|
|
static int rr_create(struct path_selector *ps, unsigned argc, char **argv)
|
|
{
|
|
struct selector *s;
|
|
|
|
s = alloc_selector();
|
|
if (!s)
|
|
return -ENOMEM;
|
|
|
|
ps->context = s;
|
|
return 0;
|
|
}
|
|
|
|
static void rr_destroy(struct path_selector *ps)
|
|
{
|
|
struct selector *s = (struct selector *) ps->context;
|
|
|
|
free_paths(&s->valid_paths);
|
|
free_paths(&s->invalid_paths);
|
|
kfree(s);
|
|
ps->context = NULL;
|
|
}
|
|
|
|
static int rr_status(struct path_selector *ps, struct dm_path *path,
|
|
status_type_t type, char *result, unsigned int maxlen)
|
|
{
|
|
struct path_info *pi;
|
|
int sz = 0;
|
|
|
|
if (!path)
|
|
DMEMIT("0 ");
|
|
else {
|
|
switch(type) {
|
|
case STATUSTYPE_INFO:
|
|
break;
|
|
case STATUSTYPE_TABLE:
|
|
pi = path->pscontext;
|
|
DMEMIT("%u ", pi->repeat_count);
|
|
break;
|
|
}
|
|
}
|
|
|
|
return sz;
|
|
}
|
|
|
|
/*
|
|
* Called during initialisation to register each path with an
|
|
* optional repeat_count.
|
|
*/
|
|
static int rr_add_path(struct path_selector *ps, struct dm_path *path,
|
|
int argc, char **argv, char **error)
|
|
{
|
|
struct selector *s = (struct selector *) ps->context;
|
|
struct path_info *pi;
|
|
unsigned repeat_count = RR_MIN_IO;
|
|
char dummy;
|
|
|
|
if (argc > 1) {
|
|
*error = "round-robin ps: incorrect number of arguments";
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* First path argument is number of I/Os before switching path */
|
|
if ((argc == 1) && (sscanf(argv[0], "%u%c", &repeat_count, &dummy) != 1)) {
|
|
*error = "round-robin ps: invalid repeat count";
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* allocate the path */
|
|
pi = kmalloc(sizeof(*pi), GFP_KERNEL);
|
|
if (!pi) {
|
|
*error = "round-robin ps: Error allocating path context";
|
|
return -ENOMEM;
|
|
}
|
|
|
|
pi->path = path;
|
|
pi->repeat_count = repeat_count;
|
|
|
|
path->pscontext = pi;
|
|
|
|
list_add_tail(&pi->list, &s->valid_paths);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void rr_fail_path(struct path_selector *ps, struct dm_path *p)
|
|
{
|
|
struct selector *s = (struct selector *) ps->context;
|
|
struct path_info *pi = p->pscontext;
|
|
|
|
list_move(&pi->list, &s->invalid_paths);
|
|
}
|
|
|
|
static int rr_reinstate_path(struct path_selector *ps, struct dm_path *p)
|
|
{
|
|
struct selector *s = (struct selector *) ps->context;
|
|
struct path_info *pi = p->pscontext;
|
|
|
|
list_move(&pi->list, &s->valid_paths);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct dm_path *rr_select_path(struct path_selector *ps,
|
|
unsigned *repeat_count, size_t nr_bytes)
|
|
{
|
|
struct selector *s = (struct selector *) ps->context;
|
|
struct path_info *pi = NULL;
|
|
|
|
if (!list_empty(&s->valid_paths)) {
|
|
pi = list_entry(s->valid_paths.next, struct path_info, list);
|
|
list_move_tail(&pi->list, &s->valid_paths);
|
|
*repeat_count = pi->repeat_count;
|
|
}
|
|
|
|
return pi ? pi->path : NULL;
|
|
}
|
|
|
|
static struct path_selector_type rr_ps = {
|
|
.name = "round-robin",
|
|
.module = THIS_MODULE,
|
|
.table_args = 1,
|
|
.info_args = 0,
|
|
.create = rr_create,
|
|
.destroy = rr_destroy,
|
|
.status = rr_status,
|
|
.add_path = rr_add_path,
|
|
.fail_path = rr_fail_path,
|
|
.reinstate_path = rr_reinstate_path,
|
|
.select_path = rr_select_path,
|
|
};
|
|
|
|
static int __init dm_rr_init(void)
|
|
{
|
|
int r = dm_register_path_selector(&rr_ps);
|
|
|
|
if (r < 0)
|
|
DMERR("register failed %d", r);
|
|
|
|
DMINFO("version 1.0.0 loaded");
|
|
|
|
return r;
|
|
}
|
|
|
|
static void __exit dm_rr_exit(void)
|
|
{
|
|
int r = dm_unregister_path_selector(&rr_ps);
|
|
|
|
if (r < 0)
|
|
DMERR("unregister failed %d", r);
|
|
}
|
|
|
|
module_init(dm_rr_init);
|
|
module_exit(dm_rr_exit);
|
|
|
|
MODULE_DESCRIPTION(DM_NAME " round-robin multipath path selector");
|
|
MODULE_AUTHOR("Sistina Software <dm-devel@redhat.com>");
|
|
MODULE_LICENSE("GPL");
|