kernel-aes67/fs/sysfs/dir.c

482 lines
10 KiB
C

/*
* dir.c - Operations for sysfs directories.
*/
#undef DEBUG
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/module.h>
#include <linux/kobject.h>
#include "sysfs.h"
DECLARE_RWSEM(sysfs_rename_sem);
static void sysfs_d_iput(struct dentry * dentry, struct inode * inode)
{
struct sysfs_dirent * sd = dentry->d_fsdata;
if (sd) {
BUG_ON(sd->s_dentry != dentry);
sd->s_dentry = NULL;
sysfs_put(sd);
}
iput(inode);
}
static struct dentry_operations sysfs_dentry_ops = {
.d_iput = sysfs_d_iput,
};
/*
* Allocates a new sysfs_dirent and links it to the parent sysfs_dirent
*/
static struct sysfs_dirent * sysfs_new_dirent(struct sysfs_dirent * parent_sd,
void * element)
{
struct sysfs_dirent * sd;
sd = kmem_cache_alloc(sysfs_dir_cachep, GFP_KERNEL);
if (!sd)
return NULL;
memset(sd, 0, sizeof(*sd));
atomic_set(&sd->s_count, 1);
INIT_LIST_HEAD(&sd->s_children);
list_add(&sd->s_sibling, &parent_sd->s_children);
sd->s_element = element;
return sd;
}
int sysfs_make_dirent(struct sysfs_dirent * parent_sd, struct dentry * dentry,
void * element, umode_t mode, int type)
{
struct sysfs_dirent * sd;
sd = sysfs_new_dirent(parent_sd, element);
if (!sd)
return -ENOMEM;
sd->s_mode = mode;
sd->s_type = type;
sd->s_dentry = dentry;
if (dentry) {
dentry->d_fsdata = sysfs_get(sd);
dentry->d_op = &sysfs_dentry_ops;
}
return 0;
}
static int init_dir(struct inode * inode)
{
inode->i_op = &sysfs_dir_inode_operations;
inode->i_fop = &sysfs_dir_operations;
/* directory inodes start off with i_nlink == 2 (for "." entry) */
inode->i_nlink++;
return 0;
}
static int init_file(struct inode * inode)
{
inode->i_size = PAGE_SIZE;
inode->i_fop = &sysfs_file_operations;
return 0;
}
static int init_symlink(struct inode * inode)
{
inode->i_op = &sysfs_symlink_inode_operations;
return 0;
}
static int create_dir(struct kobject * k, struct dentry * p,
const char * n, struct dentry ** d)
{
int error;
umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
down(&p->d_inode->i_sem);
*d = sysfs_get_dentry(p,n);
if (!IS_ERR(*d)) {
error = sysfs_make_dirent(p->d_fsdata, *d, k, mode, SYSFS_DIR);
if (!error) {
error = sysfs_create(*d, mode, init_dir);
if (!error) {
p->d_inode->i_nlink++;
(*d)->d_op = &sysfs_dentry_ops;
d_rehash(*d);
}
}
if (error && (error != -EEXIST)) {
sysfs_put((*d)->d_fsdata);
d_drop(*d);
}
dput(*d);
} else
error = PTR_ERR(*d);
up(&p->d_inode->i_sem);
return error;
}
int sysfs_create_subdir(struct kobject * k, const char * n, struct dentry ** d)
{
return create_dir(k,k->dentry,n,d);
}
/**
* sysfs_create_dir - create a directory for an object.
* @parent: parent parent object.
* @kobj: object we're creating directory for.
*/
int sysfs_create_dir(struct kobject * kobj)
{
struct dentry * dentry = NULL;
struct dentry * parent;
int error = 0;
BUG_ON(!kobj);
if (kobj->parent)
parent = kobj->parent->dentry;
else if (sysfs_mount && sysfs_mount->mnt_sb)
parent = sysfs_mount->mnt_sb->s_root;
else
return -EFAULT;
error = create_dir(kobj,parent,kobject_name(kobj),&dentry);
if (!error)
kobj->dentry = dentry;
return error;
}
/* attaches attribute's sysfs_dirent to the dentry corresponding to the
* attribute file
*/
static int sysfs_attach_attr(struct sysfs_dirent * sd, struct dentry * dentry)
{
struct attribute * attr = NULL;
struct bin_attribute * bin_attr = NULL;
int (* init) (struct inode *) = NULL;
int error = 0;
if (sd->s_type & SYSFS_KOBJ_BIN_ATTR) {
bin_attr = sd->s_element;
attr = &bin_attr->attr;
} else {
attr = sd->s_element;
init = init_file;
}
dentry->d_fsdata = sysfs_get(sd);
sd->s_dentry = dentry;
error = sysfs_create(dentry, (attr->mode & S_IALLUGO) | S_IFREG, init);
if (error) {
sysfs_put(sd);
return error;
}
if (bin_attr) {
dentry->d_inode->i_size = bin_attr->size;
dentry->d_inode->i_fop = &bin_fops;
}
dentry->d_op = &sysfs_dentry_ops;
d_rehash(dentry);
return 0;
}
static int sysfs_attach_link(struct sysfs_dirent * sd, struct dentry * dentry)
{
int err = 0;
dentry->d_fsdata = sysfs_get(sd);
sd->s_dentry = dentry;
err = sysfs_create(dentry, S_IFLNK|S_IRWXUGO, init_symlink);
if (!err) {
dentry->d_op = &sysfs_dentry_ops;
d_rehash(dentry);
} else
sysfs_put(sd);
return err;
}
static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry,
struct nameidata *nd)
{
struct sysfs_dirent * parent_sd = dentry->d_parent->d_fsdata;
struct sysfs_dirent * sd;
int err = 0;
list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
if (sd->s_type & SYSFS_NOT_PINNED) {
const unsigned char * name = sysfs_get_name(sd);
if (strcmp(name, dentry->d_name.name))
continue;
if (sd->s_type & SYSFS_KOBJ_LINK)
err = sysfs_attach_link(sd, dentry);
else
err = sysfs_attach_attr(sd, dentry);
break;
}
}
return ERR_PTR(err);
}
struct inode_operations sysfs_dir_inode_operations = {
.lookup = sysfs_lookup,
.setattr = sysfs_setattr,
};
static void remove_dir(struct dentry * d)
{
struct dentry * parent = dget(d->d_parent);
struct sysfs_dirent * sd;
down(&parent->d_inode->i_sem);
d_delete(d);
sd = d->d_fsdata;
list_del_init(&sd->s_sibling);
sysfs_put(sd);
if (d->d_inode)
simple_rmdir(parent->d_inode,d);
pr_debug(" o %s removing done (%d)\n",d->d_name.name,
atomic_read(&d->d_count));
up(&parent->d_inode->i_sem);
dput(parent);
}
void sysfs_remove_subdir(struct dentry * d)
{
remove_dir(d);
}
/**
* sysfs_remove_dir - remove an object's directory.
* @kobj: object.
*
* The only thing special about this is that we remove any files in
* the directory before we remove the directory, and we've inlined
* what used to be sysfs_rmdir() below, instead of calling separately.
*/
void sysfs_remove_dir(struct kobject * kobj)
{
struct dentry * dentry = dget(kobj->dentry);
struct sysfs_dirent * parent_sd;
struct sysfs_dirent * sd, * tmp;
if (!dentry)
return;
pr_debug("sysfs %s: removing dir\n",dentry->d_name.name);
down(&dentry->d_inode->i_sem);
parent_sd = dentry->d_fsdata;
list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) {
if (!sd->s_element || !(sd->s_type & SYSFS_NOT_PINNED))
continue;
list_del_init(&sd->s_sibling);
sysfs_drop_dentry(sd, dentry);
sysfs_put(sd);
}
up(&dentry->d_inode->i_sem);
remove_dir(dentry);
/**
* Drop reference from dget() on entrance.
*/
dput(dentry);
}
int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
{
int error = 0;
struct dentry * new_dentry, * parent;
if (!strcmp(kobject_name(kobj), new_name))
return -EINVAL;
if (!kobj->parent)
return -EINVAL;
down_write(&sysfs_rename_sem);
parent = kobj->parent->dentry;
down(&parent->d_inode->i_sem);
new_dentry = sysfs_get_dentry(parent, new_name);
if (!IS_ERR(new_dentry)) {
if (!new_dentry->d_inode) {
error = kobject_set_name(kobj, "%s", new_name);
if (!error) {
d_add(new_dentry, NULL);
d_move(kobj->dentry, new_dentry);
}
else
d_drop(new_dentry);
} else
error = -EEXIST;
dput(new_dentry);
}
up(&parent->d_inode->i_sem);
up_write(&sysfs_rename_sem);
return error;
}
static int sysfs_dir_open(struct inode *inode, struct file *file)
{
struct dentry * dentry = file->f_dentry;
struct sysfs_dirent * parent_sd = dentry->d_fsdata;
down(&dentry->d_inode->i_sem);
file->private_data = sysfs_new_dirent(parent_sd, NULL);
up(&dentry->d_inode->i_sem);
return file->private_data ? 0 : -ENOMEM;
}
static int sysfs_dir_close(struct inode *inode, struct file *file)
{
struct dentry * dentry = file->f_dentry;
struct sysfs_dirent * cursor = file->private_data;
down(&dentry->d_inode->i_sem);
list_del_init(&cursor->s_sibling);
up(&dentry->d_inode->i_sem);
release_sysfs_dirent(cursor);
return 0;
}
/* Relationship between s_mode and the DT_xxx types */
static inline unsigned char dt_type(struct sysfs_dirent *sd)
{
return (sd->s_mode >> 12) & 15;
}
static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
{
struct dentry *dentry = filp->f_dentry;
struct sysfs_dirent * parent_sd = dentry->d_fsdata;
struct sysfs_dirent *cursor = filp->private_data;
struct list_head *p, *q = &cursor->s_sibling;
ino_t ino;
int i = filp->f_pos;
switch (i) {
case 0:
ino = dentry->d_inode->i_ino;
if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
break;
filp->f_pos++;
i++;
/* fallthrough */
case 1:
ino = parent_ino(dentry);
if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
break;
filp->f_pos++;
i++;
/* fallthrough */
default:
if (filp->f_pos == 2) {
list_del(q);
list_add(q, &parent_sd->s_children);
}
for (p=q->next; p!= &parent_sd->s_children; p=p->next) {
struct sysfs_dirent *next;
const char * name;
int len;
next = list_entry(p, struct sysfs_dirent,
s_sibling);
if (!next->s_element)
continue;
name = sysfs_get_name(next);
len = strlen(name);
if (next->s_dentry)
ino = next->s_dentry->d_inode->i_ino;
else
ino = iunique(sysfs_sb, 2);
if (filldir(dirent, name, len, filp->f_pos, ino,
dt_type(next)) < 0)
return 0;
list_del(q);
list_add(q, p);
p = q;
filp->f_pos++;
}
}
return 0;
}
static loff_t sysfs_dir_lseek(struct file * file, loff_t offset, int origin)
{
struct dentry * dentry = file->f_dentry;
down(&dentry->d_inode->i_sem);
switch (origin) {
case 1:
offset += file->f_pos;
case 0:
if (offset >= 0)
break;
default:
up(&file->f_dentry->d_inode->i_sem);
return -EINVAL;
}
if (offset != file->f_pos) {
file->f_pos = offset;
if (file->f_pos >= 2) {
struct sysfs_dirent *sd = dentry->d_fsdata;
struct sysfs_dirent *cursor = file->private_data;
struct list_head *p;
loff_t n = file->f_pos - 2;
list_del(&cursor->s_sibling);
p = sd->s_children.next;
while (n && p != &sd->s_children) {
struct sysfs_dirent *next;
next = list_entry(p, struct sysfs_dirent,
s_sibling);
if (next->s_element)
n--;
p = p->next;
}
list_add_tail(&cursor->s_sibling, p);
}
}
up(&dentry->d_inode->i_sem);
return offset;
}
struct file_operations sysfs_dir_operations = {
.open = sysfs_dir_open,
.release = sysfs_dir_close,
.llseek = sysfs_dir_lseek,
.read = generic_read_dir,
.readdir = sysfs_readdir,
};
EXPORT_SYMBOL_GPL(sysfs_create_dir);
EXPORT_SYMBOL_GPL(sysfs_remove_dir);
EXPORT_SYMBOL_GPL(sysfs_rename_dir);