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/*
* Persistent Storage - ramfs parts.
*
* Copyright (C) 2010 Intel Corporation <tony.luck@intel.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 License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/fsnotify.h>
#include <linux/pagemap.h>
#include <linux/highmem.h>
#include <linux/time.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/string.h>
#include <linux/mount.h>
#include <linux/seq_file.h>
#include <linux/ramfs.h>
#include <linux/parser.h>
#include <linux/sched.h>
#include <linux/magic.h>
#include <linux/pstore.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/uaccess.h>
#include <linux/syslog.h>
#include "internal.h"
#define PSTORE_NAMELEN 64
static DEFINE_SPINLOCK(allpstore_lock);
static LIST_HEAD(allpstore);
struct pstore_private {
struct list_head list;
struct pstore_record *record;
size_t total_size;
};
struct pstore_ftrace_seq_data {
const void *ptr;
size_t off;
size_t size;
};
#define REC_SIZE sizeof(struct pstore_ftrace_record)
static void free_pstore_private(struct pstore_private *private)
{
if (!private)
return;
if (private->record) {
kfree(private->record->buf);
kfree(private->record);
}
kfree(private);
}
static void *pstore_ftrace_seq_start(struct seq_file *s, loff_t *pos)
{
struct pstore_private *ps = s->private;
struct pstore_ftrace_seq_data *data;
data = kzalloc(sizeof(*data), GFP_KERNEL);
if (!data)
return NULL;
data->off = ps->total_size % REC_SIZE;
data->off += *pos * REC_SIZE;
if (data->off + REC_SIZE > ps->total_size) {
kfree(data);
return NULL;
}
return data;
}
static void pstore_ftrace_seq_stop(struct seq_file *s, void *v)
{
kfree(v);
}
static void *pstore_ftrace_seq_next(struct seq_file *s, void *v, loff_t *pos)
{
struct pstore_private *ps = s->private;
struct pstore_ftrace_seq_data *data = v;
data->off += REC_SIZE;
if (data->off + REC_SIZE > ps->total_size)
return NULL;
(*pos)++;
return data;
}
static int pstore_ftrace_seq_show(struct seq_file *s, void *v)
{
struct pstore_private *ps = s->private;
struct pstore_ftrace_seq_data *data = v;
struct pstore_ftrace_record *rec;
rec = (struct pstore_ftrace_record *)(ps->record->buf + data->off);
seq_printf(s, "CPU:%d ts:%llu %08lx %08lx %pf <- %pF\n",
pstore_ftrace_decode_cpu(rec),
pstore_ftrace_read_timestamp(rec),
rec->ip, rec->parent_ip, (void *)rec->ip,
(void *)rec->parent_ip);
return 0;
}
static const struct seq_operations pstore_ftrace_seq_ops = {
.start = pstore_ftrace_seq_start,
.next = pstore_ftrace_seq_next,
.stop = pstore_ftrace_seq_stop,
.show = pstore_ftrace_seq_show,
};
static int pstore_check_syslog_permissions(struct pstore_private *ps)
{
switch (ps->record->type) {
case PSTORE_TYPE_DMESG:
case PSTORE_TYPE_CONSOLE:
return check_syslog_permissions(SYSLOG_ACTION_READ_ALL,
SYSLOG_FROM_READER);
default:
return 0;
}
}
static ssize_t pstore_file_read(struct file *file, char __user *userbuf,
size_t count, loff_t *ppos)
{
struct seq_file *sf = file->private_data;
struct pstore_private *ps = sf->private;
if (ps->record->type == PSTORE_TYPE_FTRACE)
return seq_read(file, userbuf, count, ppos);
return simple_read_from_buffer(userbuf, count, ppos,
ps->record->buf, ps->total_size);
}
static int pstore_file_open(struct inode *inode, struct file *file)
{
struct pstore_private *ps = inode->i_private;
struct seq_file *sf;
int err;
const struct seq_operations *sops = NULL;
err = pstore_check_syslog_permissions(ps);
if (err)
return err;
if (ps->record->type == PSTORE_TYPE_FTRACE)
sops = &pstore_ftrace_seq_ops;
err = seq_open(file, sops);
if (err < 0)
return err;
sf = file->private_data;
sf->private = ps;
return 0;
}
static loff_t pstore_file_llseek(struct file *file, loff_t off, int whence)
{
struct seq_file *sf = file->private_data;
if (sf->op)
return seq_lseek(file, off, whence);
return default_llseek(file, off, whence);
}
static const struct file_operations pstore_file_operations = {
.open = pstore_file_open,
.read = pstore_file_read,
.llseek = pstore_file_llseek,
.release = seq_release,
};
/*
* When a file is unlinked from our file system we call the
* platform driver to erase the record from persistent store.
*/
static int pstore_unlink(struct inode *dir, struct dentry *dentry)
{
struct pstore_private *p = d_inode(dentry)->i_private;
struct pstore_record *record = p->record;
int err;
err = pstore_check_syslog_permissions(p);
if (err)
return err;
if (!record->psi->erase)
return -EPERM;
mutex_lock(&record->psi->read_mutex);
record->psi->erase(record);
mutex_unlock(&record->psi->read_mutex);
return simple_unlink(dir, dentry);
}
static void pstore_evict_inode(struct inode *inode)
{
struct pstore_private *p = inode->i_private;
unsigned long flags;
clear_inode(inode);
if (p) {
spin_lock_irqsave(&allpstore_lock, flags);
list_del(&p->list);
spin_unlock_irqrestore(&allpstore_lock, flags);
free_pstore_private(p);
}
}
static const struct inode_operations pstore_dir_inode_operations = {
.lookup = simple_lookup,
.unlink = pstore_unlink,
};
static struct inode *pstore_get_inode(struct super_block *sb)
{
struct inode *inode = new_inode(sb);
if (inode) {
inode->i_ino = get_next_ino();
inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(ino
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