blob: df37bba02d0822fec85a698809b7aace23095db4 [file] [log] [blame]
/**
* @file gatorfs.c
*
* @remark Copyright 2002 OProfile authors
* @remark Read the file COPYING
*
* @author John Levon
*
* A simple filesystem for configuration and
* access of oprofile.
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/pagemap.h>
#include <linux/uaccess.h>
/* Kernel version 4.6.0 removes page_cache_{get,release} and related defines. Add them back here.
(See https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit?id=1fa64f198b9f8d6ec0f7aec7c18dc94684391140) */
#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 6, 0)
# define PAGE_CACHE_SHIFT PAGE_SHIFT
# define PAGE_CACHE_SIZE PAGE_SIZE
# define PAGE_CACHE_MASK PAGE_MASK
# define PAGE_CACHE_ALIGN(addr) (((addr)+PAGE_CACHE_SIZE-1)&PAGE_CACHE_MASK)
# define page_cache_get(page) get_page(page)
# define page_cache_release(page) put_page(page)
#endif
#define gatorfs_MAGIC 0x24051020
#define TMPBUFSIZE 50
static DEFINE_SPINLOCK(gatorfs_lock);
static struct inode *gatorfs_get_inode(struct super_block *sb, int mode)
{
struct inode *inode = new_inode(sb);
if (inode) {
inode->i_ino = get_next_ino();
inode->i_mode = mode;
#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 12, 0)
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
#else
inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
#endif
}
return inode;
}
static const struct super_operations s_ops = {
.statfs = simple_statfs,
.drop_inode = generic_delete_inode,
};
static ssize_t gatorfs_ulong_to_user(unsigned long val, char __user *buf, size_t count, loff_t *offset)
{
char tmpbuf[TMPBUFSIZE];
size_t maxlen = snprintf(tmpbuf, TMPBUFSIZE, "%lu\n", val);
if (maxlen > TMPBUFSIZE)
maxlen = TMPBUFSIZE;
return simple_read_from_buffer(buf, count, offset, tmpbuf, maxlen);
}
static ssize_t gatorfs_u64_to_user(u64 val, char __user *buf, size_t count, loff_t *offset)
{
char tmpbuf[TMPBUFSIZE];
size_t maxlen = snprintf(tmpbuf, TMPBUFSIZE, "%llu\n", val);
if (maxlen > TMPBUFSIZE)
maxlen = TMPBUFSIZE;
return simple_read_from_buffer(buf, count, offset, tmpbuf, maxlen);
}
static int gatorfs_ulong_from_user(unsigned long *val, char const __user *buf, size_t count)
{
char tmpbuf[TMPBUFSIZE];
unsigned long flags;
if (!count)
return 0;
if (count > TMPBUFSIZE - 1)
return -EINVAL;
memset(tmpbuf, 0x0, TMPBUFSIZE);
if (copy_from_user(tmpbuf, buf, count))
return -EFAULT;
spin_lock_irqsave(&gatorfs_lock, flags);
*val = simple_strtoul(tmpbuf, NULL, 0);
spin_unlock_irqrestore(&gatorfs_lock, flags);
return 0;
}
static int gatorfs_u64_from_user(u64 *val, char const __user *buf, size_t count)
{
char tmpbuf[TMPBUFSIZE];
unsigned long flags;
if (!count)
return 0;
if (count > TMPBUFSIZE - 1)
return -EINVAL;
memset(tmpbuf, 0x0, TMPBUFSIZE);
if (copy_from_user(tmpbuf, buf, count))
return -EFAULT;
spin_lock_irqsave(&gatorfs_lock, flags);
*val = simple_strtoull(tmpbuf, NULL, 0);
spin_unlock_irqrestore(&gatorfs_lock, flags);
return 0;
}
static ssize_t ulong_read_file(struct file *file, char __user *buf, size_t count, loff_t *offset)
{
unsigned long *val = file->private_data;
return gatorfs_ulong_to_user(*val, buf, count, offset);
}
static ssize_t u64_read_file(struct file *file, char __user *buf, size_t count, loff_t *offset)
{
u64 *val = file->private_data;
return gatorfs_u64_to_user(*val, buf, count, offset);
}
static ssize_t ulong_write_file(struct file *file, char const __user *buf, size_t count, loff_t *offset)
{
unsigned long *value = file->private_data;
int retval;
if (*offset)
return -EINVAL;
retval = gatorfs_ulong_from_user(value, buf, count);
if (retval)
return retval;
return count;
}
static ssize_t u64_write_file(struct file *file, char const __user *buf, size_t count, loff_t *offset)
{
u64 *value = file->private_data;
int retval;
if (*offset)
return -EINVAL;
retval = gatorfs_u64_from_user(value, buf, count);
if (retval)
return retval;
return count;
}
static int default_open(struct inode *inode, struct file *filp)
{
if (inode->i_private)
filp->private_data = inode->i_private;
return 0;
}
static const struct file_operations ulong_fops = {
.read = ulong_read_file,
.write = ulong_write_file,
.open = default_open,
};
static const struct file_operations u64_fops = {
.read = u64_read_file,
.write = u64_write_file,
.open = default_open,
};
static const struct file_operations ulong_ro_fops = {
.read = ulong_read_file,
.open = default_open,
};
static const struct file_operations u64_ro_fops = {
.read = u64_read_file,
.open = default_open,
};
static struct dentry *__gatorfs_create_file(struct super_block *sb,
struct dentry *root,
char const *name,
const struct file_operations *fops,
int perm)
{
struct dentry *dentry;
struct inode *inode;
dentry = d_alloc_name(root, name);
if (!dentry)
return NULL;
inode = gatorfs_get_inode(sb, S_IFREG | perm);
if (!inode) {
dput(dentry);
return NULL;
}
inode->i_fop = fops;
d_add(dentry, inode);
return dentry;
}
int gatorfs_create_ulong(struct super_block *sb, struct dentry *root,
char const *name, unsigned long *val)
{
struct dentry *d = __gatorfs_create_file(sb, root, name,
&ulong_fops, 0644);
if (!d)
return -EFAULT;
d->d_inode->i_private = val;
return 0;
}
static int gatorfs_create_u64(struct super_block *sb, struct dentry *root,
char const *name, u64 *val)
{
struct dentry *d = __gatorfs_create_file(sb, root, name,
&u64_fops, 0644);
if (!d)
return -EFAULT;
d->d_inode->i_private = val;
return 0;
}
int gatorfs_create_ro_ulong(struct super_block *sb, struct dentry *root,
char const *name, unsigned long *val)
{
struct dentry *d = __gatorfs_create_file(sb, root, name,
&ulong_ro_fops, 0444);
if (!d)
return -EFAULT;
d->d_inode->i_private = val;
return 0;
}
static int gatorfs_create_ro_u64(struct super_block *sb, struct dentry *root,
char const *name, u64 *val)
{
struct dentry *d =
__gatorfs_create_file(sb, root, name, &u64_ro_fops, 0444);
if (!d)
return -EFAULT;
d->d_inode->i_private = val;
return 0;
}
static ssize_t atomic_read_file(struct file *file, char __user *buf, size_t count, loff_t *offset)
{
atomic_t *val = file->private_data;
return gatorfs_ulong_to_user(atomic_read(val), buf, count, offset);
}
static const struct file_operations atomic_ro_fops = {
.read = atomic_read_file,
.open = default_open,
};
static int gatorfs_create_file_data(struct super_block *sb, struct dentry *root,
char const *name, const struct file_operations *fops,
void * private_data)
{
struct dentry * dentry = __gatorfs_create_file(sb, root, name, fops, 0644);
if (!dentry)
return -EFAULT;
dentry->d_inode->i_private = private_data;
return 0;
}
static int gatorfs_create_file(struct super_block *sb, struct dentry *root,
char const *name, const struct file_operations *fops)
{
return gatorfs_create_file_data(sb, root, name, fops, NULL);
}
static int gatorfs_create_file_perm(struct super_block *sb, struct dentry *root,
char const *name,
const struct file_operations *fops, int perm)
{
if (!__gatorfs_create_file(sb, root, name, fops, perm))
return -EFAULT;
return 0;
}
struct dentry *gatorfs_mkdir(struct super_block *sb,
struct dentry *root, char const *name)
{
struct dentry *dentry;
struct inode *inode;
dentry = d_alloc_name(root, name);
if (!dentry)
return NULL;
inode = gatorfs_get_inode(sb, S_IFDIR | 0755);
if (!inode) {
dput(dentry);
return NULL;
}
inode->i_op = &simple_dir_inode_operations;
inode->i_fop = &simple_dir_operations;
d_add(dentry, inode);
return dentry;
}
static int gatorfs_fill_super(struct super_block *sb, void *data, int silent)
{
struct inode *root_inode;
struct dentry *root_dentry;
sb->s_blocksize = PAGE_CACHE_SIZE;
sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
sb->s_magic = gatorfs_MAGIC;
sb->s_op = &s_ops;
sb->s_time_gran = 1;
root_inode = gatorfs_get_inode(sb, S_IFDIR | 0755);
if (!root_inode)
return -ENOMEM;
root_inode->i_op = &simple_dir_inode_operations;
root_inode->i_fop = &simple_dir_operations;
root_dentry = d_make_root(root_inode);
if (!root_dentry) {
return -ENOMEM;
}
sb->s_root = root_dentry;
gator_op_create_files(sb, root_dentry);
return 0;
}
static struct dentry *gatorfs_mount(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data)
{
return mount_nodev(fs_type, flags, data, gatorfs_fill_super);
}
static struct file_system_type gatorfs_type = {
.owner = THIS_MODULE,
.name = "gatorfs",
.mount = gatorfs_mount,
.kill_sb = kill_litter_super,
};
static int __init gatorfs_register(void)
{
return register_filesystem(&gatorfs_type);
}
static void gatorfs_unregister(void)
{
unregister_filesystem(&gatorfs_type);
}