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/*
* Copyright 2004 Peter M. Jones <pjones@redhat.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* 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 Licens
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-
*
*/
#include <linux/list.h>
#include <linux/genhd.h>
#include <linux/spinlock.h>
#include <linux/parser.h>
#include <linux/capability.h>
#include <linux/bitops.h>
#include <scsi/scsi.h>
#include <linux/cdrom.h>
int blk_verify_command(struct blk_cmd_filter *filter,
unsigned char *cmd, int has_write_perm)
{
/* root can do any command. */
if (capable(CAP_SYS_RAWIO))
return 0;
/* if there's no filter set, assume we're filtering everything out */
if (!filter)
return -EPERM;
/* Anybody who can open the device can do a read-safe command */
if (test_bit(cmd[0], filter->read_ok))
return 0;
/* Write-safe commands require a writable open */
if (test_bit(cmd[0], filter->write_ok) && has_write_perm)
return 0;
return -EPERM;
}
EXPORT_SYMBOL(blk_verify_command);
/* and now, the sysfs stuff */
static ssize_t rcf_cmds_show(struct blk_cmd_filter *filter, char *page,
int rw)
{
char *npage = page;
unsigned long *okbits;
int i;
if (rw == READ)
okbits = filter->read_ok;
else
okbits = filter->write_ok;
for (i = 0; i < BLK_SCSI_MAX_CMDS; i++) {
if (test_bit(i, okbits)) {
sprintf(npage, "%02x", i);
npage += 2;
if (i < BLK_SCSI_MAX_CMDS - 1)
sprintf(npage++, " ");
}
}
if (npage != page)
npage += sprintf(npage, "\n");
return npage - page;
}
static ssize_t rcf_readcmds_show(struct blk_cmd_filter *filter, char *page)
{
return rcf_cmds_show(filter, page, READ);
}
static ssize_t rcf_writecmds_show(struct blk_cmd_filter *filter,
char *page)
{
return rcf_cmds_show(filter, page, WRITE);
}
static ssize_t rcf_cmds_store(struct blk_cmd_filter *filter,
const char *page, size_t count, int rw)
{
ssize_t ret = 0;
unsigned long okbits[BLK_SCSI_CMD_PER_LONG], *target_okbits;
int cmd, status, len;
substring_t ss;
memset(&okbits, 0, sizeof(okbits));
for (len = strlen(page); len > 0; len -= 3) {
if (len < 2)
break;
ss.from = (char *) page + ret;
ss.to = (char *) page + ret + 2;
ret += 3;
status = match_hex(&ss, &cmd);
/* either of these cases means invalid input, so do nothing. */
if (status || cmd >= BLK_SCSI_MAX_CMDS)
return -EINVAL;
__set_bit(cmd, okbits);
}
if (rw == READ)
target_okbits = filter->read_ok;
else
target_okbits = filter->write_ok;
memmove(target_okbits, okbits, sizeof(okbits));
return count;
}
static ssize_t rcf_readcmds_store(struct blk_cmd_filter *filter,
const char *page, size_t count)
{
return rcf_cmds_store(filter, page, count, READ);
}
static ssize_t rcf_writecmds_store(struct blk_cmd_filter *filter,
const char *page, size_t count)
{
return rcf_cmds_store(filter, page, count, WRITE);
}
struct rcf_sysfs_entry {
struct attribute attr;
ssize_t (*show)(struct blk_cmd_filter *, char *);
ssize_t (*store)(struct blk_cmd_filter *, const char *, size_t);
};
static struct rcf_sysfs_entry rcf_readcmds_entry = {
.attr = { .name = "read_table", .mode = S_IRUGO | S_IWUSR },
.show = rcf_readcmds_show,
.store = rcf_readcmds_store,
};
static struct rcf_sysfs_entry rcf_writecmds_entry = {
.attr = {.name = "write_table", .mode = S_IRUGO | S_IWUSR },
.show = rcf_writecmds_show,
.store = rcf_writecmds_store,
};
static struct attribute *default_attrs[] = {
&rcf_readcmds_entry.attr,
&rcf_writecmds_entry.attr,
NULL,
};
#define to_rcf(atr) container_of((atr), struct rcf_sysfs_entry, attr)
static ssize_t
rcf_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
{
struct rcf_sysfs_entry *entry = to_rcf(attr);
struct blk_cmd_filter *filter;
filter = container_of(kobj, struct blk_cmd_filter, kobj);
if (entry->show)
return entry->show(filter, page);
return 0;
}
static ssize_t
rcf_attr_store(struct kobject *kobj, struct attribute *attr,
const char *page, size_t length)
{
struct rcf_sysfs_entry *entry = to_rcf(attr);
struct blk_cmd_filter *filter;
if (!capable(CAP_SYS_RAWIO))
return -EPERM;
if (!entry->store)
return -EINVAL;
filter = container_of(kobj, struct blk_cmd_filter, kobj);
return entry->store(filter, page, length);
}
static struct sysfs_ops rcf_sysfs_ops = {
.show = rcf_attr_show,
.store = rcf_attr_store,
};
static struct kobj_type rcf_ktype = {
.sysfs_ops = &rcf_sysfs_ops,
.default_attrs = default_attrs,
};
int blk_register_filter(struct gendisk *disk)
{
int ret;
struct blk_cmd_filter *filter = &disk->queue->cmd_filter;
struct kobject *parent = kobject_get(disk->holder_dir->parent);
if (!parent)
return -ENODEV;
ret = kobject_init_and_add(&filter->kobj, &rcf_ktype, parent,
"%s", "cmd_filter");
if (ret < 0)
return ret;
return 0;
}
void blk_unregister_filter(struct gendisk *disk)
{
struct blk_cmd_filter *filter = &disk->queue->cmd_filter;
kobject_put(&filter->kobj);
kobject_put(disk->holder_dir->parent);
}
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