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configfs: Add permission and ownership to configfs objects.
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configfs always made item and attribute ownership root.root and
permissions based on a umask of 022.  Add ->setattr() to allow
chown(2)/chmod(2), and persist the changes for the lifetime of the
items and attributes.

Signed-off-by: Joel Becker <[email protected]>
Signed-off-by: Mark Fasheh <[email protected]>
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Joel Becker authored and Mark Fasheh committed Feb 3, 2006
1 parent 62ca3d2 commit 3d0f89b
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Showing 8 changed files with 179 additions and 37 deletions.
2 changes: 2 additions & 0 deletions Documentation/filesystems/configfs/configfs_example.c
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Original file line number Diff line number Diff line change
Expand Up @@ -320,6 +320,7 @@ static struct config_item_type simple_children_type = {
.ct_item_ops = &simple_children_item_ops,
.ct_group_ops = &simple_children_group_ops,
.ct_attrs = simple_children_attrs,
.ct_owner = THIS_MODULE,
};

static struct configfs_subsystem simple_children_subsys = {
Expand Down Expand Up @@ -403,6 +404,7 @@ static struct config_item_type group_children_type = {
.ct_item_ops = &group_children_item_ops,
.ct_group_ops = &group_children_group_ops,
.ct_attrs = group_children_attrs,
.ct_owner = THIS_MODULE,
};

static struct configfs_subsystem group_children_subsys = {
Expand Down
11 changes: 8 additions & 3 deletions fs/configfs/configfs_internal.h
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Original file line number Diff line number Diff line change
Expand Up @@ -36,6 +36,7 @@ struct configfs_dirent {
int s_type;
umode_t s_mode;
struct dentry * s_dentry;
struct iattr * s_iattr;
};

#define CONFIGFS_ROOT 0x0001
Expand All @@ -48,10 +49,11 @@ struct configfs_dirent {
#define CONFIGFS_NOT_PINNED (CONFIGFS_ITEM_ATTR)

extern struct vfsmount * configfs_mount;
extern kmem_cache_t *configfs_dir_cachep;

extern int configfs_is_root(struct config_item *item);

extern struct inode * configfs_new_inode(mode_t mode);
extern struct inode * configfs_new_inode(mode_t mode, struct configfs_dirent *);
extern int configfs_create(struct dentry *, int mode, int (*init)(struct inode *));

extern int configfs_create_file(struct config_item *, const struct configfs_attribute *);
Expand All @@ -63,6 +65,7 @@ extern void configfs_hash_and_remove(struct dentry * dir, const char * name);

extern const unsigned char * configfs_get_name(struct configfs_dirent *sd);
extern void configfs_drop_dentry(struct configfs_dirent *sd, struct dentry *parent);
extern int configfs_setattr(struct dentry *dentry, struct iattr *iattr);

extern int configfs_pin_fs(void);
extern void configfs_release_fs(void);
Expand Down Expand Up @@ -120,8 +123,10 @@ static inline struct config_item *configfs_get_config_item(struct dentry *dentry

static inline void release_configfs_dirent(struct configfs_dirent * sd)
{
if (!(sd->s_type & CONFIGFS_ROOT))
kfree(sd);
if (!(sd->s_type & CONFIGFS_ROOT)) {
kfree(sd->s_iattr);
kmem_cache_free(configfs_dir_cachep, sd);
}
}

static inline struct configfs_dirent * configfs_get(struct configfs_dirent * sd)
Expand Down
36 changes: 26 additions & 10 deletions fs/configfs/dir.c
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Original file line number Diff line number Diff line change
Expand Up @@ -72,7 +72,7 @@ static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent * pare
{
struct configfs_dirent * sd;

sd = kmalloc(sizeof(*sd), GFP_KERNEL);
sd = kmem_cache_alloc(configfs_dir_cachep, GFP_KERNEL);
if (!sd)
return NULL;

Expand Down Expand Up @@ -136,13 +136,19 @@ static int create_dir(struct config_item * k, struct dentry * p,
int error;
umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;

error = configfs_create(d, mode, init_dir);
error = configfs_make_dirent(p->d_fsdata, d, k, mode,
CONFIGFS_DIR);
if (!error) {
error = configfs_make_dirent(p->d_fsdata, d, k, mode,
CONFIGFS_DIR);
error = configfs_create(d, mode, init_dir);
if (!error) {
p->d_inode->i_nlink++;
(d)->d_op = &configfs_dentry_ops;
} else {
struct configfs_dirent *sd = d->d_fsdata;
if (sd) {
list_del_init(&sd->s_sibling);
configfs_put(sd);
}
}
}
return error;
Expand Down Expand Up @@ -182,12 +188,19 @@ int configfs_create_link(struct configfs_symlink *sl,
int err = 0;
umode_t mode = S_IFLNK | S_IRWXUGO;

err = configfs_create(dentry, mode, init_symlink);
err = configfs_make_dirent(parent->d_fsdata, dentry, sl, mode,
CONFIGFS_ITEM_LINK);
if (!err) {
err = configfs_make_dirent(parent->d_fsdata, dentry, sl,
mode, CONFIGFS_ITEM_LINK);
err = configfs_create(dentry, mode, init_symlink);
if (!err)
dentry->d_op = &configfs_dentry_ops;
else {
struct configfs_dirent *sd = dentry->d_fsdata;
if (sd) {
list_del_init(&sd->s_sibling);
configfs_put(sd);
}
}
}
return err;
}
Expand Down Expand Up @@ -241,13 +254,15 @@ static int configfs_attach_attr(struct configfs_dirent * sd, struct dentry * den
struct configfs_attribute * attr = sd->s_element;
int error;

dentry->d_fsdata = configfs_get(sd);
sd->s_dentry = dentry;
error = configfs_create(dentry, (attr->ca_mode & S_IALLUGO) | S_IFREG, init_file);
if (error)
if (error) {
configfs_put(sd);
return error;
}

dentry->d_op = &configfs_dentry_ops;
dentry->d_fsdata = configfs_get(sd);
sd->s_dentry = dentry;
d_rehash(dentry);

return 0;
Expand Down Expand Up @@ -839,6 +854,7 @@ struct inode_operations configfs_dir_inode_operations = {
.symlink = configfs_symlink,
.unlink = configfs_unlink,
.lookup = configfs_lookup,
.setattr = configfs_setattr,
};

#if 0
Expand Down
19 changes: 10 additions & 9 deletions fs/configfs/file.c
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Original file line number Diff line number Diff line change
Expand Up @@ -26,7 +26,6 @@

#include <linux/fs.h>
#include <linux/module.h>
#include <linux/dnotify.h>
#include <linux/slab.h>
#include <asm/uaccess.h>
#include <asm/semaphore.h>
Expand Down Expand Up @@ -150,7 +149,7 @@ configfs_read_file(struct file *file, char __user *buf, size_t count, loff_t *pp
/**
* fill_write_buffer - copy buffer from userspace.
* @buffer: data buffer for file.
* @userbuf: data from user.
* @buf: data from user.
* @count: number of bytes in @userbuf.
*
* Allocate @buffer->page if it hasn't been already, then
Expand All @@ -177,8 +176,9 @@ fill_write_buffer(struct configfs_buffer * buffer, const char __user * buf, size

/**
* flush_write_buffer - push buffer to config_item.
* @file: file pointer.
* @dentry: dentry to the attribute
* @buffer: data buffer for file.
* @count: number of bytes
*
* Get the correct pointers for the config_item and the attribute we're
* dealing with, then call the store() method for the attribute,
Expand Down Expand Up @@ -217,15 +217,16 @@ static ssize_t
configfs_write_file(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
{
struct configfs_buffer * buffer = file->private_data;
ssize_t len;

down(&buffer->sem);
count = fill_write_buffer(buffer,buf,count);
if (count > 0)
count = flush_write_buffer(file->f_dentry,buffer,count);
if (count > 0)
*ppos += count;
len = fill_write_buffer(buffer, buf, count);
if (len > 0)
len = flush_write_buffer(file->f_dentry, buffer, count);
if (len > 0)
*ppos += len;
up(&buffer->sem);
return count;
return len;
}

static int check_perm(struct inode * inode, struct file * file)
Expand Down
117 changes: 108 additions & 9 deletions fs/configfs/inode.c
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Original file line number Diff line number Diff line change
Expand Up @@ -31,6 +31,7 @@
#include <linux/pagemap.h>
#include <linux/namei.h>
#include <linux/backing-dev.h>
#include <linux/capability.h>

#include <linux/configfs.h>
#include "configfs_internal.h"
Expand All @@ -48,18 +49,107 @@ static struct backing_dev_info configfs_backing_dev_info = {
.capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
};

struct inode * configfs_new_inode(mode_t mode)
static struct inode_operations configfs_inode_operations ={
.setattr = configfs_setattr,
};

int configfs_setattr(struct dentry * dentry, struct iattr * iattr)
{
struct inode * inode = dentry->d_inode;
struct configfs_dirent * sd = dentry->d_fsdata;
struct iattr * sd_iattr;
unsigned int ia_valid = iattr->ia_valid;
int error;

if (!sd)
return -EINVAL;

sd_iattr = sd->s_iattr;

error = inode_change_ok(inode, iattr);
if (error)
return error;

error = inode_setattr(inode, iattr);
if (error)
return error;

if (!sd_iattr) {
/* setting attributes for the first time, allocate now */
sd_iattr = kmalloc(sizeof(struct iattr), GFP_KERNEL);
if (!sd_iattr)
return -ENOMEM;
/* assign default attributes */
memset(sd_iattr, 0, sizeof(struct iattr));
sd_iattr->ia_mode = sd->s_mode;
sd_iattr->ia_uid = 0;
sd_iattr->ia_gid = 0;
sd_iattr->ia_atime = sd_iattr->ia_mtime = sd_iattr->ia_ctime = CURRENT_TIME;
sd->s_iattr = sd_iattr;
}

/* attributes were changed atleast once in past */

if (ia_valid & ATTR_UID)
sd_iattr->ia_uid = iattr->ia_uid;
if (ia_valid & ATTR_GID)
sd_iattr->ia_gid = iattr->ia_gid;
if (ia_valid & ATTR_ATIME)
sd_iattr->ia_atime = timespec_trunc(iattr->ia_atime,
inode->i_sb->s_time_gran);
if (ia_valid & ATTR_MTIME)
sd_iattr->ia_mtime = timespec_trunc(iattr->ia_mtime,
inode->i_sb->s_time_gran);
if (ia_valid & ATTR_CTIME)
sd_iattr->ia_ctime = timespec_trunc(iattr->ia_ctime,
inode->i_sb->s_time_gran);
if (ia_valid & ATTR_MODE) {
umode_t mode = iattr->ia_mode;

if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
mode &= ~S_ISGID;
sd_iattr->ia_mode = sd->s_mode = mode;
}

return error;
}

static inline void set_default_inode_attr(struct inode * inode, mode_t mode)
{
inode->i_mode = mode;
inode->i_uid = 0;
inode->i_gid = 0;
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
}

static inline void set_inode_attr(struct inode * inode, struct iattr * iattr)
{
inode->i_mode = iattr->ia_mode;
inode->i_uid = iattr->ia_uid;
inode->i_gid = iattr->ia_gid;
inode->i_atime = iattr->ia_atime;
inode->i_mtime = iattr->ia_mtime;
inode->i_ctime = iattr->ia_ctime;
}

struct inode * configfs_new_inode(mode_t mode, struct configfs_dirent * sd)
{
struct inode * inode = new_inode(configfs_sb);
if (inode) {
inode->i_mode = mode;
inode->i_uid = 0;
inode->i_gid = 0;
inode->i_blksize = PAGE_CACHE_SIZE;
inode->i_blocks = 0;
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
inode->i_mapping->a_ops = &configfs_aops;
inode->i_mapping->backing_dev_info = &configfs_backing_dev_info;
inode->i_op = &configfs_inode_operations;

if (sd->s_iattr) {
/* sysfs_dirent has non-default attributes
* get them for the new inode from persistent copy
* in sysfs_dirent
*/
set_inode_attr(inode, sd->s_iattr);
} else
set_default_inode_attr(inode, mode);
}
return inode;
}
Expand All @@ -70,7 +160,8 @@ int configfs_create(struct dentry * dentry, int mode, int (*init)(struct inode *
struct inode * inode = NULL;
if (dentry) {
if (!dentry->d_inode) {
if ((inode = configfs_new_inode(mode))) {
struct configfs_dirent *sd = dentry->d_fsdata;
if ((inode = configfs_new_inode(mode, sd))) {
if (dentry->d_parent && dentry->d_parent->d_inode) {
struct inode *p_inode = dentry->d_parent->d_inode;
p_inode->i_mtime = p_inode->i_ctime = CURRENT_TIME;
Expand Down Expand Up @@ -103,7 +194,7 @@ int configfs_create(struct dentry * dentry, int mode, int (*init)(struct inode *
*/
const unsigned char * configfs_get_name(struct configfs_dirent *sd)
{
struct attribute * attr;
struct configfs_attribute *attr;

if (!sd || !sd->s_element)
BUG();
Expand All @@ -114,7 +205,7 @@ const unsigned char * configfs_get_name(struct configfs_dirent *sd)

if (sd->s_type & CONFIGFS_ITEM_ATTR) {
attr = sd->s_element;
return attr->name;
return attr->ca_name;
}
return NULL;
}
Expand All @@ -130,13 +221,17 @@ void configfs_drop_dentry(struct configfs_dirent * sd, struct dentry * parent)

if (dentry) {
spin_lock(&dcache_lock);
spin_lock(&dentry->d_lock);
if (!(d_unhashed(dentry) && dentry->d_inode)) {
dget_locked(dentry);
__d_drop(dentry);
spin_unlock(&dentry->d_lock);
spin_unlock(&dcache_lock);
simple_unlink(parent->d_inode, dentry);
} else
} else {
spin_unlock(&dentry->d_lock);
spin_unlock(&dcache_lock);
}
}
}

Expand All @@ -145,6 +240,10 @@ void configfs_hash_and_remove(struct dentry * dir, const char * name)
struct configfs_dirent * sd;
struct configfs_dirent * parent_sd = dir->d_fsdata;

if (dir->d_inode == NULL)
/* no inode means this hasn't been made visible yet */
return;

mutex_lock(&dir->d_inode->i_mutex);
list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
if (!sd->s_element)
Expand Down
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