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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2010-2019 Junjiro R. Okajima
*
* This program, aufs 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, see <http://www.gnu.org/licenses/>.
*/
/*
* procfs interfaces
*/
#include <linux/proc_fs.h>
#include "aufs.h"
static int au_procfs_plm_release(struct inode *inode, struct file *file)
{
struct au_sbinfo *sbinfo;
sbinfo = file->private_data;
if (sbinfo) {
au_plink_maint_leave(sbinfo);
kobject_put(&sbinfo->si_kobj);
}
return 0;
}
static void au_procfs_plm_write_clean(struct file *file)
{
struct au_sbinfo *sbinfo;
sbinfo = file->private_data;
if (sbinfo)
au_plink_clean(sbinfo->si_sb, /*verbose*/0);
}
static int au_procfs_plm_write_si(struct file *file, unsigned long id)
{
int err;
struct super_block *sb;
struct au_sbinfo *sbinfo;
struct hlist_bl_node *pos;
err = -EBUSY;
if (unlikely(file->private_data))
goto out;
sb = NULL;
/* don't use au_sbilist_lock() here */
hlist_bl_lock(&au_sbilist);
hlist_bl_for_each_entry(sbinfo, pos, &au_sbilist, si_list)
if (id == sysaufs_si_id(sbinfo)) {
kobject_get(&sbinfo->si_kobj);
sb = sbinfo->si_sb;
break;
}
hlist_bl_unlock(&au_sbilist);
err = -EINVAL;
if (unlikely(!sb))
goto out;
err = au_plink_maint_enter(sb);
if (!err)
/* keep kobject_get() */
file->private_data = sbinfo;
else
kobject_put(&sbinfo->si_kobj);
out:
return err;
}
/*
* Accept a valid "si=xxxx" only.
* Once it is accepted successfully, accept "clean" too.
*/
static ssize_t au_procfs_plm_write(struct file *file, const char __user *ubuf,
size_t count, loff_t *ppos)
{
ssize_t err;
unsigned long id;
/* last newline is allowed */
char buf[3 + sizeof(unsigned long) * 2 + 1];
err = -EACCES;
if (unlikely(!capable(CAP_SYS_ADMIN)))
goto out;
err = -EINVAL;
if (unlikely(count > sizeof(buf)))
goto out;
err = copy_from_user(buf, ubuf, count);
if (unlikely(err)) {
err = -EFAULT;
goto out;
}
buf[count] = 0;
err = -EINVAL;
if (!strcmp("clean", buf)) {
au_procfs_plm_write_clean(file);
goto out_success;
} else if (unlikely(strncmp("si=", buf, 3)))
goto out;
err = kstrtoul(buf + 3, 16, &id);
if (unlikely(err))
goto out;
err = au_procfs_plm_write_si(file, id);
if (unlikely(err))
goto out;
out_success:
err = count; /* success */
out:
return err;
}
static const struct file_operations au_procfs_plm_fop = {
.write = au_procfs_plm_write,
.release = au_procfs_plm_release,
.owner = THIS_MODULE
};
/* ---------------------------------------------------------------------- */
static struct proc_dir_entry *au_procfs_dir;
void au_procfs_fin(void)
{
remove_proc_entry(AUFS_PLINK_MAINT_NAME, au_procfs_dir);
remove_proc_entry(AUFS_PLINK_MAINT_DIR, NULL);
}
int __init au_procfs_init(void)
{
int err;
struct proc_dir_entry *entry;
err = -ENOMEM;
au_procfs_dir = proc_mkdir(AUFS_PLINK_MAINT_DIR, NULL);
if (unlikely(!au_procfs_dir))
goto out;
entry = proc_create(AUFS_PLINK_MAINT_NAME, S_IFREG | 0200,
au_procfs_dir, &au_procfs_plm_fop);
if (unlikely(!entry))
goto out_dir;
err = 0;
goto out; /* success */
out_dir:
remove_proc_entry(AUFS_PLINK_MAINT_DIR, NULL);
out:
return err;
}
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