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Commit f7a5d012 authored by Patrick Mochel's avatar Patrick Mochel
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sysfs: split up inode.c into different files for different purposes. 

- new files file.c, dir.c, symlink.c, mount.c.

- Purely cosmetic (for now). Should make it easier to add new filetypes.
parent f5fa274f
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Showing with 788 additions and 760 deletions
fs/sysfs/Makefile
View file @ f7a5d012
...@@ -2,6 +2,6 @@ ...@@ -2,6 +2,6 @@
# Makefile for the sysfs virtual filesystem # Makefile for the sysfs virtual filesystem
# #
export-objs := inode.o export-objs := file.o dir.o symlink.o
obj-y := inode.o obj-y := inode.o file.o dir.o symlink.o mount.o
fs/sysfs/dir.c 0 → 100644
View file @ f7a5d012
/*
* 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"
static int sysfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
{
int res;
mode = (mode & (S_IRWXUGO|S_ISVTX)) | S_IFDIR;
res = sysfs_mknod(dir, dentry, mode, 0);
if (!res)
dir->i_nlink++;
return res;
}
/**
* 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;
if (!kobj)
return -EINVAL;
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;
down(&parent->d_inode->i_sem);
dentry = sysfs_get_dentry(parent,kobj->name);
if (!IS_ERR(dentry)) {
dentry->d_fsdata = (void *)kobj;
kobj->dentry = dentry;
error = sysfs_mkdir(parent->d_inode,dentry,
(S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO));
} else
error = PTR_ERR(dentry);
up(&parent->d_inode->i_sem);
return error;
}
/**
* 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 list_head * node, * next;
struct dentry * dentry = dget(kobj->dentry);
struct dentry * parent;
if (!dentry)
return;
pr_debug("sysfs %s: removing dir\n",dentry->d_name.name);
parent = dget(dentry->d_parent);
down(&parent->d_inode->i_sem);
down(&dentry->d_inode->i_sem);
list_for_each_safe(node,next,&dentry->d_subdirs) {
struct dentry * d = dget(list_entry(node,struct dentry,d_child));
/**
* Make sure dentry is still there
*/
pr_debug(" o %s: ",d->d_name.name);
if (d->d_inode) {
pr_debug("removing");
/**
* Unlink and unhash.
*/
simple_unlink(dentry->d_inode,d);
d_delete(d);
/**
* Drop reference from initial sysfs_get_dentry().
*/
dput(d);
}
pr_debug(" done (%d)\n",atomic_read(&d->d_count));
/**
* drop reference from dget() above.
*/
dput(d);
}
up(&dentry->d_inode->i_sem);
d_invalidate(dentry);
simple_rmdir(parent->d_inode,dentry);
d_delete(dentry);
pr_debug(" o %s removing done (%d)\n",dentry->d_name.name,
atomic_read(&dentry->d_count));
/**
* Drop reference from initial sysfs_get_dentry().
*/
dput(dentry);
/**
* Drop reference from dget() on entrance.
*/
dput(dentry);
up(&parent->d_inode->i_sem);
dput(parent);
}
EXPORT_SYMBOL(sysfs_create_dir);
EXPORT_SYMBOL(sysfs_remove_dir);
fs/sysfs/file.c 0 → 100644
View file @ f7a5d012
/*
* file.c - operations for regular (text) files.
*/
#include <linux/module.h>
#include <linux/dnotify.h>
#include <linux/kobject.h>
#include "sysfs.h"
static int sysfs_create(struct inode *dir, struct dentry *dentry, int mode)
{
int res;
mode = (mode & S_IALLUGO) | S_IFREG;
res = sysfs_mknod(dir, dentry, mode, 0);
return res;
}
#define to_subsys(k) container_of(k,struct subsystem,kset.kobj)
#define to_sattr(a) container_of(a,struct subsys_attribute,attr)
/**
* Subsystem file operations.
* These operations allow subsystems to have files that can be
* read/written.
*/
static ssize_t
subsys_attr_show(struct kobject * kobj, struct attribute * attr, char * page)
{
struct subsystem * s = to_subsys(kobj);
struct subsys_attribute * sattr = to_sattr(attr);
ssize_t ret = 0;
if (sattr->show)
ret = sattr->show(s,page);
return ret;
}
static ssize_t
subsys_attr_store(struct kobject * kobj, struct attribute * attr,
const char * page, size_t count)
{
struct subsystem * s = to_subsys(kobj);
struct subsys_attribute * sattr = to_sattr(attr);
ssize_t ret = 0;
if (sattr->store)
ret = sattr->store(s,page,count);
return ret;
}
static struct sysfs_ops subsys_sysfs_ops = {
.show = subsys_attr_show,
.store = subsys_attr_store,
};
struct sysfs_buffer {
size_t count;
loff_t pos;
char * page;
struct sysfs_ops * ops;
};
/**
* fill_read_buffer - allocate and fill buffer from object.
* @file: file pointer.
* @buffer: data buffer for file.
*
* Allocate @buffer->page, if it hasn't been already, then call the
* kobject's show() method to fill the buffer with this attribute's
* data.
* This is called only once, on the file's first read.
*/
static int fill_read_buffer(struct file * file, struct sysfs_buffer * buffer)
{
struct attribute * attr = file->f_dentry->d_fsdata;
struct kobject * kobj = file->f_dentry->d_parent->d_fsdata;
struct sysfs_ops * ops = buffer->ops;
int ret = 0;
size_t count;
if (!buffer->page)
buffer->page = (char *) __get_free_page(GFP_KERNEL);
if (!buffer->page)
return -ENOMEM;
count = ops->show(kobj,attr,buffer->page);
if (count >= 0)
buffer->count = count;
else
ret = count;
return ret;
}
/**
* flush_read_buffer - push buffer to userspace.
* @buffer: data buffer for file.
* @userbuf: user-passed buffer.
* @count: number of bytes requested.
* @ppos: file position.
*
* Copy the buffer we filled in fill_read_buffer() to userspace.
* This is done at the reader's leisure, copying and advancing
* the amount they specify each time.
* This may be called continuously until the buffer is empty.
*/
static int flush_read_buffer(struct sysfs_buffer * buffer, char * buf,
size_t count, loff_t * ppos)
{
int error;
if (count > (buffer->count - *ppos))
count = buffer->count - *ppos;
error = copy_to_user(buf,buffer->page + *ppos,count);
if (!error)
*ppos += count;
return error ? -EFAULT : count;
}
/**
* sysfs_read_file - read an attribute.
* @file: file pointer.
* @buf: buffer to fill.
* @count: number of bytes to read.
* @ppos: starting offset in file.
*
* Userspace wants to read an attribute file. The attribute descriptor
* is in the file's ->d_fsdata. The target object is in the directory's
* ->d_fsdata.
*
* We call fill_read_buffer() to allocate and fill the buffer from the
* object's show() method exactly once (if the read is happening from
* the beginning of the file). That should fill the entire buffer with
* all the data the object has to offer for that attribute.
* We then call flush_read_buffer() to copy the buffer to userspace
* in the increments specified.
*/
static ssize_t
sysfs_read_file(struct file *file, char *buf, size_t count, loff_t *ppos)
{
struct sysfs_buffer * buffer = file->private_data;
ssize_t retval = 0;
if (!*ppos) {
if ((retval = fill_read_buffer(file,buffer)))
return retval;
}
pr_debug("%s: count = %d, ppos = %lld, buf = %s\n",
__FUNCTION__,count,*ppos,buffer->page);
return flush_read_buffer(buffer,buf,count,ppos);
}
/**
* fill_write_buffer - copy buffer from userspace.
* @buffer: data buffer for file.
* @userbuf: data from user.
* @count: number of bytes in @userbuf.
*
* Allocate @buffer->page if it hasn't been already, then
* copy the user-supplied buffer into it.
*/
static int
fill_write_buffer(struct sysfs_buffer * buffer, const char * buf, size_t count)
{
int error;
if (!buffer->page)
buffer->page = (char *)__get_free_page(GFP_KERNEL);
if (!buffer->page)
return -ENOMEM;
if (count >= PAGE_SIZE)
count = PAGE_SIZE - 1;
error = copy_from_user(buffer->page,buf,count);
return error ? -EFAULT : count;
}
/**
* flush_write_buffer - push buffer to kobject.
* @file: file pointer.
* @buffer: data buffer for file.
*
* Get the correct pointers for the kobject and the attribute we're
* dealing with, then call the store() method for the attribute,
* passing the buffer that we acquired in fill_write_buffer().
*/
static int
flush_write_buffer(struct file * file, struct sysfs_buffer * buffer, size_t count)
{
struct attribute * attr = file->f_dentry->d_fsdata;
struct kobject * kobj = file->f_dentry->d_parent->d_fsdata;
struct sysfs_ops * ops = buffer->ops;
return ops->store(kobj,attr,buffer->page,count);
}
/**
* sysfs_write_file - write an attribute.
* @file: file pointer
* @buf: data to write
* @count: number of bytes
* @ppos: starting offset
*
* Similar to sysfs_read_file(), though working in the opposite direction.
* We allocate and fill the data from the user in fill_write_buffer(),
* then push it to the kobject in flush_write_buffer().
* There is no easy way for us to know if userspace is only doing a partial
* write, so we don't support them. We expect the entire buffer to come
* on the first write.
* Hint: if you're writing a value, first read the file, modify only the
* the value you're changing, then write entire buffer back.
*/
static ssize_t
sysfs_write_file(struct file *file, const char *buf, size_t count, loff_t *ppos)
{
struct sysfs_buffer * buffer = file->private_data;
count = fill_write_buffer(buffer,buf,count);
if (count > 0)
count = flush_write_buffer(file,buffer,count);
if (count > 0)
*ppos += count;
return count;
}
static int check_perm(struct inode * inode, struct file * file)
{
struct kobject * kobj = kobject_get(file->f_dentry->d_parent->d_fsdata);
struct attribute * attr = file->f_dentry->d_fsdata;
struct sysfs_buffer * buffer;
struct sysfs_ops * ops = NULL;
int error = 0;
if (!kobj || !attr)
goto Einval;
/* if the kobject has no ktype, then we assume that it is a subsystem
* itself, and use ops for it.
*/
if (kobj->kset && kobj->kset->ktype)
ops = kobj->kset->ktype->sysfs_ops;
else if (kobj->ktype)
ops = kobj->ktype->sysfs_ops;
else
ops = &subsys_sysfs_ops;
/* No sysfs operations, either from having no subsystem,
* or the subsystem have no operations.
*/
if (!ops)
goto Eaccess;
/* File needs write support.
* The inode's perms must say it's ok,
* and we must have a store method.
*/
if (file->f_mode & FMODE_WRITE) {
if (!(inode->i_mode & S_IWUGO) || !ops->store)
goto Eaccess;
}
/* File needs read support.
* The inode's perms must say it's ok, and we there
* must be a show method for it.
*/
if (file->f_mode & FMODE_READ) {
if (!(inode->i_mode & S_IRUGO) || !ops->show)
goto Eaccess;
}
/* No error? Great, allocate a buffer for the file, and store it
* it in file->private_data for easy access.
*/
buffer = kmalloc(sizeof(struct sysfs_buffer),GFP_KERNEL);
if (buffer) {
memset(buffer,0,sizeof(struct sysfs_buffer));
buffer->ops = ops;
file->private_data = buffer;
} else
error = -ENOMEM;
goto Done;
Einval:
error = -EINVAL;
goto Done;
Eaccess:
error = -EACCES;
Done:
if (error && kobj)
kobject_put(kobj);
return error;
}
static int sysfs_open_file(struct inode * inode, struct file * filp)
{
return check_perm(inode,filp);
}
static int sysfs_release(struct inode * inode, struct file * filp)
{
struct kobject * kobj = filp->f_dentry->d_parent->d_fsdata;
struct sysfs_buffer * buffer = filp->private_data;
if (kobj)
kobject_put(kobj);
if (buffer) {
if (buffer->page)
free_page((unsigned long)buffer->page);
kfree(buffer);
}
return 0;
}
struct file_operations sysfs_file_operations = {
.read = sysfs_read_file,
.write = sysfs_write_file,
.llseek = generic_file_llseek,
.open = sysfs_open_file,
.release = sysfs_release,
};
/**
* sysfs_create_file - create an attribute file for an object.
* @kobj: object we're creating for.
* @attr: atrribute descriptor.
*/
int sysfs_create_file(struct kobject * kobj, struct attribute * attr)
{
struct dentry * dentry;
struct dentry * parent;
int error = 0;
if (!kobj || !attr)
return -EINVAL;
parent = kobj->dentry;
down(&parent->d_inode->i_sem);
dentry = sysfs_get_dentry(parent,attr->name);
if (!IS_ERR(dentry)) {
dentry->d_fsdata = (void *)attr;
error = sysfs_create(parent->d_inode,dentry,attr->mode);
} else
error = PTR_ERR(dentry);
up(&parent->d_inode->i_sem);
return error;
}
/**
* sysfs_update_file - update the modified timestamp on an object attribute.
* @kobj: object we're acting for.
* @attr: attribute descriptor.
*
* Also call dnotify for the dentry, which lots of userspace programs
* use.
*/
int sysfs_update_file(struct kobject * kobj, struct attribute * attr)
{
struct dentry * dir = kobj->dentry;
struct dentry * victim;
int res = -ENOENT;
down(&dir->d_inode->i_sem);
victim = sysfs_get_dentry(dir, attr->name);
if (!IS_ERR(victim)) {
/* make sure dentry is really there */
if (victim->d_inode &&
(victim->d_parent->d_inode == dir->d_inode)) {
victim->d_inode->i_mtime = CURRENT_TIME;
dnotify_parent(victim, DN_MODIFY);
/**
* Drop reference from initial sysfs_get_dentry().
*/
dput(victim);
res = 0;
}
/**
* Drop the reference acquired from sysfs_get_dentry() above.
*/
dput(victim);
}
up(&dir->d_inode->i_sem);
return res;
}
/**
* sysfs_remove_file - remove an object attribute.
* @kobj: object we're acting for.
* @attr: attribute descriptor.
*
* Hash the attribute name and kill the victim.
*/
void sysfs_remove_file(struct kobject * kobj, struct attribute * attr)
{
sysfs_hash_and_remove(kobj->dentry,attr->name);
}
EXPORT_SYMBOL(sysfs_create_file);
EXPORT_SYMBOL(sysfs_remove_file);
EXPORT_SYMBOL(sysfs_update_file);
fs/sysfs/inode.c
View file @ f7a5d012
/* /*
* sysfs.c - The filesystem to export kernel objects. * inode.c - basic inode and dentry operations.
* *
* Copyright (c) 2001, 2002 Patrick Mochel * sysfs is Copyright (c) 2001-3 Patrick Mochel
*
* This program 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, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* This is a simple, ramfs-based filesystem, designed to export kernel
* objects, their attributes, and the linkgaes between each other.
* *
* Please see Documentation/filesystems/sysfs.txt for more information. * Please see Documentation/filesystems/sysfs.txt for more information.
*/ */
#undef DEBUG #undef DEBUG
#include <linux/list.h>
#include <linux/init.h>
#include <linux/pagemap.h> #include <linux/pagemap.h>
#include <linux/stat.h>
#include <linux/fs.h>
#include <linux/dcache.h>
#include <linux/namei.h> #include <linux/namei.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/backing-dev.h> #include <linux/backing-dev.h>
#include <linux/kobject.h>
#include <linux/mount.h>
#include <linux/dnotify.h>
#include <asm/uaccess.h>
/* Random magic number */ extern struct file_operations sysfs_file_operations;
#define SYSFS_MAGIC 0x62656572
static struct address_space_operations sysfs_aops = {
.readpage = simple_readpage,
.prepare_write = simple_prepare_write,
.commit_write = simple_commit_write
};
static struct super_operations sysfs_ops;
static struct file_operations sysfs_file_operations;
static struct address_space_operations sysfs_aops;
static struct vfsmount *sysfs_mount;
static struct backing_dev_info sysfs_backing_dev_info = { static struct backing_dev_info sysfs_backing_dev_info = {
.ra_pages = 0, /* No readahead */ .ra_pages = 0, /* No readahead */
.memory_backed = 1, /* Does not contribute to dirty memory */ .memory_backed = 1, /* Does not contribute to dirty memory */
}; };
static struct inode *sysfs_get_inode(struct super_block *sb, int mode, int dev) struct inode *sysfs_get_inode(struct super_block *sb, int mode, int dev)
{ {
struct inode *inode = new_inode(sb); struct inode *inode = new_inode(sb);
...@@ -91,7 +64,7 @@ static struct inode *sysfs_get_inode(struct super_block *sb, int mode, int dev) ...@@ -91,7 +64,7 @@ static struct inode *sysfs_get_inode(struct super_block *sb, int mode, int dev)
return inode; return inode;
} }
static int sysfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) int sysfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
{ {
struct inode *inode; struct inode *inode;
int error = 0; int error = 0;
...@@ -108,432 +81,7 @@ static int sysfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t ...@@ -108,432 +81,7 @@ static int sysfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t
return error; return error;
} }
static int sysfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) struct dentry * sysfs_get_dentry(struct dentry * parent, const char * name)
{
int res;
mode = (mode & (S_IRWXUGO|S_ISVTX)) | S_IFDIR;
res = sysfs_mknod(dir, dentry, mode, 0);
if (!res)
dir->i_nlink++;
return res;
}
static int sysfs_create(struct inode *dir, struct dentry *dentry, int mode)
{
int res;
mode = (mode & S_IALLUGO) | S_IFREG;
res = sysfs_mknod(dir, dentry, mode, 0);
return res;
}
static int sysfs_symlink(struct inode * dir, struct dentry *dentry, const char * symname)
{
struct inode *inode;
int error = -ENOSPC;
if (dentry->d_inode)
return -EEXIST;
inode = sysfs_get_inode(dir->i_sb, S_IFLNK|S_IRWXUGO, 0);
if (inode) {
int l = strlen(symname)+1;
error = page_symlink(inode, symname, l);
if (!error) {
d_instantiate(dentry, inode);
dget(dentry);
} else
iput(inode);
}
return error;
}
#define to_subsys(k) container_of(k,struct subsystem,kset.kobj)
#define to_sattr(a) container_of(a,struct subsys_attribute,attr)
/**
* Subsystem file operations.
* These operations allow subsystems to have files that can be
* read/written.
*/
static ssize_t
subsys_attr_show(struct kobject * kobj, struct attribute * attr, char * page)
{
struct subsystem * s = to_subsys(kobj);
struct subsys_attribute * sattr = to_sattr(attr);
ssize_t ret = 0;
if (sattr->show)
ret = sattr->show(s,page);
return ret;
}
static ssize_t
subsys_attr_store(struct kobject * kobj, struct attribute * attr,
const char * page, size_t count)
{
struct subsystem * s = to_subsys(kobj);
struct subsys_attribute * sattr = to_sattr(attr);
ssize_t ret = 0;
if (sattr->store)
ret = sattr->store(s,page,count);
return ret;
}
static struct sysfs_ops subsys_sysfs_ops = {
.show = subsys_attr_show,
.store = subsys_attr_store,
};
struct sysfs_buffer {
size_t count;
loff_t pos;
char * page;
struct sysfs_ops * ops;
};
/**
* fill_read_buffer - allocate and fill buffer from object.
* @file: file pointer.
* @buffer: data buffer for file.
*
* Allocate @buffer->page, if it hasn't been already, then call the
* kobject's show() method to fill the buffer with this attribute's
* data.
* This is called only once, on the file's first read.
*/
static int fill_read_buffer(struct file * file, struct sysfs_buffer * buffer)
{
struct attribute * attr = file->f_dentry->d_fsdata;
struct kobject * kobj = file->f_dentry->d_parent->d_fsdata;
struct sysfs_ops * ops = buffer->ops;
int ret = 0;
size_t count;
if (!buffer->page)
buffer->page = (char *) __get_free_page(GFP_KERNEL);
if (!buffer->page)
return -ENOMEM;
count = ops->show(kobj,attr,buffer->page);
if (count >= 0)
buffer->count = count;
else
ret = count;
return ret;
}
/**
* flush_read_buffer - push buffer to userspace.
* @buffer: data buffer for file.
* @userbuf: user-passed buffer.
* @count: number of bytes requested.
* @ppos: file position.
*
* Copy the buffer we filled in fill_read_buffer() to userspace.
* This is done at the reader's leisure, copying and advancing
* the amount they specify each time.
* This may be called continuously until the buffer is empty.
*/
static int flush_read_buffer(struct sysfs_buffer * buffer, char * buf,
size_t count, loff_t * ppos)
{
int error;
if (count > (buffer->count - *ppos))
count = buffer->count - *ppos;
error = copy_to_user(buf,buffer->page + *ppos,count);
if (!error)
*ppos += count;
return error ? -EFAULT : count;
}
/**
* sysfs_read_file - read an attribute.
* @file: file pointer.
* @buf: buffer to fill.
* @count: number of bytes to read.
* @ppos: starting offset in file.
*
* Userspace wants to read an attribute file. The attribute descriptor
* is in the file's ->d_fsdata. The target object is in the directory's
* ->d_fsdata.
*
* We call fill_read_buffer() to allocate and fill the buffer from the
* object's show() method exactly once (if the read is happening from
* the beginning of the file). That should fill the entire buffer with
* all the data the object has to offer for that attribute.
* We then call flush_read_buffer() to copy the buffer to userspace
* in the increments specified.
*/
static ssize_t
sysfs_read_file(struct file *file, char *buf, size_t count, loff_t *ppos)
{
struct sysfs_buffer * buffer = file->private_data;
ssize_t retval = 0;
if (!*ppos) {
if ((retval = fill_read_buffer(file,buffer)))
return retval;
}
pr_debug("%s: count = %d, ppos = %lld, buf = %s\n",
__FUNCTION__,count,*ppos,buffer->page);
return flush_read_buffer(buffer,buf,count,ppos);
}
/**
* fill_write_buffer - copy buffer from userspace.
* @buffer: data buffer for file.
* @userbuf: data from user.
* @count: number of bytes in @userbuf.
*
* Allocate @buffer->page if it hasn't been already, then
* copy the user-supplied buffer into it.
*/
static int
fill_write_buffer(struct sysfs_buffer * buffer, const char * buf, size_t count)
{
int error;
if (!buffer->page)
buffer->page = (char *)__get_free_page(GFP_KERNEL);
if (!buffer->page)
return -ENOMEM;
if (count >= PAGE_SIZE)
count = PAGE_SIZE - 1;
error = copy_from_user(buffer->page,buf,count);
return error ? -EFAULT : count;
}
/**
* flush_write_buffer - push buffer to kobject.
* @file: file pointer.
* @buffer: data buffer for file.
*
* Get the correct pointers for the kobject and the attribute we're
* dealing with, then call the store() method for the attribute,
* passing the buffer that we acquired in fill_write_buffer().
*/
static int
flush_write_buffer(struct file * file, struct sysfs_buffer * buffer, size_t count)
{
struct attribute * attr = file->f_dentry->d_fsdata;
struct kobject * kobj = file->f_dentry->d_parent->d_fsdata;
struct sysfs_ops * ops = buffer->ops;
return ops->store(kobj,attr,buffer->page,count);
}
/**
* sysfs_write_file - write an attribute.
* @file: file pointer
* @buf: data to write
* @count: number of bytes
* @ppos: starting offset
*
* Similar to sysfs_read_file(), though working in the opposite direction.
* We allocate and fill the data from the user in fill_write_buffer(),
* then push it to the kobject in flush_write_buffer().
* There is no easy way for us to know if userspace is only doing a partial
* write, so we don't support them. We expect the entire buffer to come
* on the first write.
* Hint: if you're writing a value, first read the file, modify only the
* the value you're changing, then write entire buffer back.
*/
static ssize_t
sysfs_write_file(struct file *file, const char *buf, size_t count, loff_t *ppos)
{
struct sysfs_buffer * buffer = file->private_data;
count = fill_write_buffer(buffer,buf,count);
if (count > 0)
count = flush_write_buffer(file,buffer,count);
if (count > 0)
*ppos += count;
return count;
}
static int check_perm(struct inode * inode, struct file * file)
{
struct kobject * kobj = kobject_get(file->f_dentry->d_parent->d_fsdata);
struct attribute * attr = file->f_dentry->d_fsdata;
struct sysfs_buffer * buffer;
struct sysfs_ops * ops = NULL;
int error = 0;
if (!kobj || !attr)
goto Einval;
/* if the kobject has no ktype, then we assume that it is a subsystem
* itself, and use ops for it.
*/
if (kobj->kset && kobj->kset->ktype)
ops = kobj->kset->ktype->sysfs_ops;
else if (kobj->ktype)
ops = kobj->ktype->sysfs_ops;
else
ops = &subsys_sysfs_ops;
/* No sysfs operations, either from having no subsystem,
* or the subsystem have no operations.
*/
if (!ops)
goto Eaccess;
/* File needs write support.
* The inode's perms must say it's ok,
* and we must have a store method.
*/
if (file->f_mode & FMODE_WRITE) {
if (!(inode->i_mode & S_IWUGO) || !ops->store)
goto Eaccess;
}
/* File needs read support.
* The inode's perms must say it's ok, and we there
* must be a show method for it.
*/
if (file->f_mode & FMODE_READ) {
if (!(inode->i_mode & S_IRUGO) || !ops->show)
goto Eaccess;
}
/* No error? Great, allocate a buffer for the file, and store it
* it in file->private_data for easy access.
*/
buffer = kmalloc(sizeof(struct sysfs_buffer),GFP_KERNEL);
if (buffer) {
memset(buffer,0,sizeof(struct sysfs_buffer));
buffer->ops = ops;
file->private_data = buffer;
} else
error = -ENOMEM;
goto Done;
Einval:
error = -EINVAL;
goto Done;
Eaccess:
error = -EACCES;
Done:
if (error && kobj)
kobject_put(kobj);
return error;
}
static int sysfs_open_file(struct inode * inode, struct file * filp)
{
return check_perm(inode,filp);
}
static int sysfs_release(struct inode * inode, struct file * filp)
{
struct kobject * kobj = filp->f_dentry->d_parent->d_fsdata;
struct sysfs_buffer * buffer = filp->private_data;
if (kobj)
kobject_put(kobj);
if (buffer) {
if (buffer->page)
free_page((unsigned long)buffer->page);
kfree(buffer);
}
return 0;
}
static struct file_operations sysfs_file_operations = {
.read = sysfs_read_file,
.write = sysfs_write_file,
.llseek = generic_file_llseek,
.open = sysfs_open_file,
.release = sysfs_release,
};
static struct address_space_operations sysfs_aops = {
.readpage = simple_readpage,
.prepare_write = simple_prepare_write,
.commit_write = simple_commit_write
};
static struct super_operations sysfs_ops = {
.statfs = simple_statfs,
.drop_inode = generic_delete_inode,
};
static int sysfs_fill_super(struct super_block *sb, void *data, int silent)
{
struct inode *inode;
struct dentry *root;
sb->s_blocksize = PAGE_CACHE_SIZE;
sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
sb->s_magic = SYSFS_MAGIC;
sb->s_op = &sysfs_ops;
inode = sysfs_get_inode(sb, S_IFDIR | 0755, 0);
if (!inode) {
pr_debug("%s: could not get inode!\n",__FUNCTION__);
return -ENOMEM;
}
root = d_alloc_root(inode);
if (!root) {
pr_debug("%s: could not get root dentry!\n",__FUNCTION__);
iput(inode);
return -ENOMEM;
}
sb->s_root = root;
return 0;
}
static struct super_block *sysfs_get_sb(struct file_system_type *fs_type,
int flags, char *dev_name, void *data)
{
return get_sb_single(fs_type, flags, data, sysfs_fill_super);
}
static struct file_system_type sysfs_fs_type = {
.owner = THIS_MODULE,
.name = "sysfs",
.get_sb = sysfs_get_sb,
.kill_sb = kill_litter_super,
};
static int __init sysfs_init(void)
{
int err;
err = register_filesystem(&sysfs_fs_type);
if (!err) {
sysfs_mount = kern_mount(&sysfs_fs_type);
if (IS_ERR(sysfs_mount)) {
printk(KERN_ERR "sysfs: could not mount!\n");
err = PTR_ERR(sysfs_mount);
sysfs_mount = NULL;
}
}
return err;
}
core_initcall(sysfs_init);
static struct dentry * get_dentry(struct dentry * parent, const char * name)
{ {
struct qstr qstr; struct qstr qstr;
...@@ -543,157 +91,12 @@ static struct dentry * get_dentry(struct dentry * parent, const char * name) ...@@ -543,157 +91,12 @@ static struct dentry * get_dentry(struct dentry * parent, const char * name)
return lookup_hash(&qstr,parent); return lookup_hash(&qstr,parent);
} }
void sysfs_hash_and_remove(struct dentry * dir, const char * name)
/**
* 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;
if (!kobj)
return -EINVAL;
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;
down(&parent->d_inode->i_sem);
dentry = get_dentry(parent,kobj->name);
if (!IS_ERR(dentry)) {
dentry->d_fsdata = (void *)kobj;
kobj->dentry = dentry;
error = sysfs_mkdir(parent->d_inode,dentry,
(S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO));
} else
error = PTR_ERR(dentry);
up(&parent->d_inode->i_sem);
return error;
}
/**
* sysfs_create_file - create an attribute file for an object.
* @kobj: object we're creating for.
* @attr: atrribute descriptor.
*/
int sysfs_create_file(struct kobject * kobj, struct attribute * attr)
{
struct dentry * dentry;
struct dentry * parent;
int error = 0;
if (!kobj || !attr)
return -EINVAL;
parent = kobj->dentry;
down(&parent->d_inode->i_sem);
dentry = get_dentry(parent,attr->name);
if (!IS_ERR(dentry)) {
dentry->d_fsdata = (void *)attr;
error = sysfs_create(parent->d_inode,dentry,attr->mode);
} else
error = PTR_ERR(dentry);
up(&parent->d_inode->i_sem);
return error;
}
static int object_depth(struct kobject * kobj)
{
struct kobject * p = kobj;
int depth = 0;
do { depth++; } while ((p = p->parent));
return depth;
}
static int object_path_length(struct kobject * kobj)
{
struct kobject * p = kobj;
int length = 1;
do {
length += strlen(p->name) + 1;
p = p->parent;
} while (p);
return length;
}
static void fill_object_path(struct kobject * kobj, char * buffer, int length)
{
struct kobject * p;
--length;
for (p = kobj; p; p = p->parent) {
int cur = strlen(p->name);
/* back up enough to print this bus id with '/' */
length -= cur;
strncpy(buffer + length,p->name,cur);
*(buffer + --length) = '/';
}
}
/**
* sysfs_create_link - create symlink between two objects.
* @kobj: object whose directory we're creating the link in.
* @target: object we're pointing to.
* @name: name of the symlink.
*/
int sysfs_create_link(struct kobject * kobj, struct kobject * target, char * name)
{
struct dentry * dentry = kobj->dentry;
struct dentry * d;
int error = 0;
int size;
int depth;
char * path;
char * s;
depth = object_depth(kobj);
size = object_path_length(target) + depth * 3 - 1;
if (size > PATH_MAX)
return -ENAMETOOLONG;
pr_debug("%s: depth = %d, size = %d\n",__FUNCTION__,depth,size);
path = kmalloc(size,GFP_KERNEL);
if (!path)
return -ENOMEM;
memset(path,0,size);
for (s = path; depth--; s += 3)
strcpy(s,"../");
fill_object_path(target,path,size);
pr_debug("%s: path = '%s'\n",__FUNCTION__,path);
down(&dentry->d_inode->i_sem);
d = get_dentry(dentry,name);
if (!IS_ERR(d))
error = sysfs_symlink(dentry->d_inode,d,path);
else
error = PTR_ERR(d);
up(&dentry->d_inode->i_sem);
kfree(path);
return error;
}
static void hash_and_remove(struct dentry * dir, const char * name)
{ {
struct dentry * victim; struct dentry * victim;
down(&dir->d_inode->i_sem); down(&dir->d_inode->i_sem);
victim = get_dentry(dir,name); victim = sysfs_get_dentry(dir,name);
if (!IS_ERR(victim)) { if (!IS_ERR(victim)) {
/* make sure dentry is really there */ /* make sure dentry is really there */
if (victim->d_inode && if (victim->d_inode &&
...@@ -704,161 +107,16 @@ static void hash_and_remove(struct dentry * dir, const char * name) ...@@ -704,161 +107,16 @@ static void hash_and_remove(struct dentry * dir, const char * name)
pr_debug("sysfs: Removing %s (%d)\n", victim->d_name.name, pr_debug("sysfs: Removing %s (%d)\n", victim->d_name.name,
atomic_read(&victim->d_count)); atomic_read(&victim->d_count));
/** /**
* Drop reference from initial get_dentry(). * Drop reference from initial sysfs_get_dentry().
*/ */
dput(victim); dput(victim);
} }
/** /**
* Drop the reference acquired from get_dentry() above. * Drop the reference acquired from sysfs_get_dentry() above.
*/ */
dput(victim); dput(victim);
} }
up(&dir->d_inode->i_sem); up(&dir->d_inode->i_sem);
} }
/**
* sysfs_update_file - update the modified timestamp on an object attribute.
* @kobj: object we're acting for.
* @attr: attribute descriptor.
*
* Also call dnotify for the dentry, which lots of userspace programs
* use.
*/
int sysfs_update_file(struct kobject * kobj, struct attribute * attr)
{
struct dentry * dir = kobj->dentry;
struct dentry * victim;
int res = -ENOENT;
down(&dir->d_inode->i_sem);
victim = get_dentry(dir, attr->name);
if (!IS_ERR(victim)) {
/* make sure dentry is really there */
if (victim->d_inode &&
(victim->d_parent->d_inode == dir->d_inode)) {
victim->d_inode->i_mtime = CURRENT_TIME;
dnotify_parent(victim, DN_MODIFY);
/**
* Drop reference from initial get_dentry().
*/
dput(victim);
res = 0;
}
/**
* Drop the reference acquired from get_dentry() above.
*/
dput(victim);
}
up(&dir->d_inode->i_sem);
return res;
}
/**
* sysfs_remove_file - remove an object attribute.
* @kobj: object we're acting for.
* @attr: attribute descriptor.
*
* Hash the attribute name and kill the victim.
*/
void sysfs_remove_file(struct kobject * kobj, struct attribute * attr)
{
hash_and_remove(kobj->dentry,attr->name);
}
/**
* sysfs_remove_link - remove symlink in object's directory.
* @kobj: object we're acting for.
* @name: name of the symlink to remove.
*/
void sysfs_remove_link(struct kobject * kobj, char * name)
{
hash_and_remove(kobj->dentry,name);
}
/**
* 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 list_head * node, * next;
struct dentry * dentry = dget(kobj->dentry);
struct dentry * parent;
if (!dentry)
return;
pr_debug("sysfs %s: removing dir\n",dentry->d_name.name);
parent = dget(dentry->d_parent);
down(&parent->d_inode->i_sem);
down(&dentry->d_inode->i_sem);
list_for_each_safe(node,next,&dentry->d_subdirs) {
struct dentry * d = dget(list_entry(node,struct dentry,d_child));
/**
* Make sure dentry is still there
*/
pr_debug(" o %s: ",d->d_name.name);
if (d->d_inode) {
pr_debug("removing");
/**
* Unlink and unhash.
*/
simple_unlink(dentry->d_inode,d);
d_delete(d);
/**
* Drop reference from initial get_dentry().
*/
dput(d);
}
pr_debug(" done (%d)\n",atomic_read(&d->d_count));
/**
* drop reference from dget() above.
*/
dput(d);
}
up(&dentry->d_inode->i_sem);
d_invalidate(dentry);
simple_rmdir(parent->d_inode,dentry);
d_delete(dentry);
pr_debug(" o %s removing done (%d)\n",dentry->d_name.name,
atomic_read(&dentry->d_count));
/**
* Drop reference from initial get_dentry().
*/
dput(dentry);
/**
* Drop reference from dget() on entrance.
*/
dput(dentry);
up(&parent->d_inode->i_sem);
dput(parent);
}
EXPORT_SYMBOL(sysfs_create_file);
EXPORT_SYMBOL(sysfs_remove_file);
EXPORT_SYMBOL(sysfs_update_file);
EXPORT_SYMBOL(sysfs_create_link);
EXPORT_SYMBOL(sysfs_remove_link);
EXPORT_SYMBOL(sysfs_create_dir);
EXPORT_SYMBOL(sysfs_remove_dir);
fs/sysfs/mount.c 0 → 100644
View file @ f7a5d012
/*
* mount.c - operations for initializing and mounting sysfs.
*/
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/pagemap.h>
#include "sysfs.h"
/* Random magic number */
#define SYSFS_MAGIC 0x62656572
struct vfsmount *sysfs_mount;
static struct super_operations sysfs_ops = {
.statfs = simple_statfs,
.drop_inode = generic_delete_inode,
};
static int sysfs_fill_super(struct super_block *sb, void *data, int silent)
{
struct inode *inode;
struct dentry *root;
sb->s_blocksize = PAGE_CACHE_SIZE;
sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
sb->s_magic = SYSFS_MAGIC;
sb->s_op = &sysfs_ops;
inode = sysfs_get_inode(sb, S_IFDIR | 0755, 0);
if (!inode) {
pr_debug("%s: could not get inode!\n",__FUNCTION__);
return -ENOMEM;
}
root = d_alloc_root(inode);
if (!root) {
pr_debug("%s: could not get root dentry!\n",__FUNCTION__);
iput(inode);
return -ENOMEM;
}
sb->s_root = root;
return 0;
}
static struct super_block *sysfs_get_sb(struct file_system_type *fs_type,
int flags, char *dev_name, void *data)
{
return get_sb_single(fs_type, flags, data, sysfs_fill_super);
}
static struct file_system_type sysfs_fs_type = {
.name = "sysfs",
.get_sb = sysfs_get_sb,
.kill_sb = kill_litter_super,
};
static int __init sysfs_init(void)
{
int err;
err = register_filesystem(&sysfs_fs_type);
if (!err) {
sysfs_mount = kern_mount(&sysfs_fs_type);
if (IS_ERR(sysfs_mount)) {
printk(KERN_ERR "sysfs: could not mount!\n");
err = PTR_ERR(sysfs_mount);
sysfs_mount = NULL;
}
}
return err;
}
core_initcall(sysfs_init);
fs/sysfs/symlink.c 0 → 100644
View file @ f7a5d012
/*
* symlink.c - operations for sysfs symlinks.
*/
#include <linux/fs.h>
#include <linux/module.h>
#include <linux/kobject.h>
#include "sysfs.h"
static int sysfs_symlink(struct inode * dir, struct dentry *dentry, const char * symname)
{
struct inode *inode;
int error = -ENOSPC;
if (dentry->d_inode)
return -EEXIST;
inode = sysfs_get_inode(dir->i_sb, S_IFLNK|S_IRWXUGO, 0);
if (inode) {
int l = strlen(symname)+1;
error = page_symlink(inode, symname, l);
if (!error) {
d_instantiate(dentry, inode);
dget(dentry);
} else
iput(inode);
}
return error;
}
static int object_depth(struct kobject * kobj)
{
struct kobject * p = kobj;
int depth = 0;
do { depth++; } while ((p = p->parent));
return depth;
}
static int object_path_length(struct kobject * kobj)
{
struct kobject * p = kobj;
int length = 1;
do {
length += strlen(p->name) + 1;
p = p->parent;
} while (p);
return length;
}
static void fill_object_path(struct kobject * kobj, char * buffer, int length)
{
struct kobject * p;
--length;
for (p = kobj; p; p = p->parent) {
int cur = strlen(p->name);
/* back up enough to print this bus id with '/' */
length -= cur;
strncpy(buffer + length,p->name,cur);
*(buffer + --length) = '/';
}
}
/**
* sysfs_create_link - create symlink between two objects.
* @kobj: object whose directory we're creating the link in.
* @target: object we're pointing to.
* @name: name of the symlink.
*/
int sysfs_create_link(struct kobject * kobj, struct kobject * target, char * name)
{
struct dentry * dentry = kobj->dentry;
struct dentry * d;
int error = 0;
int size;
int depth;
char * path;
char * s;
depth = object_depth(kobj);
size = object_path_length(target) + depth * 3 - 1;
if (size > PATH_MAX)
return -ENAMETOOLONG;
pr_debug("%s: depth = %d, size = %d\n",__FUNCTION__,depth,size);
path = kmalloc(size,GFP_KERNEL);
if (!path)
return -ENOMEM;
memset(path,0,size);
for (s = path; depth--; s += 3)
strcpy(s,"../");
fill_object_path(target,path,size);
pr_debug("%s: path = '%s'\n",__FUNCTION__,path);
down(&dentry->d_inode->i_sem);
d = sysfs_get_dentry(dentry,name);
if (!IS_ERR(d))
error = sysfs_symlink(dentry->d_inode,d,path);
else
error = PTR_ERR(d);
up(&dentry->d_inode->i_sem);
kfree(path);
return error;
}
/**
* sysfs_remove_link - remove symlink in object's directory.
* @kobj: object we're acting for.
* @name: name of the symlink to remove.
*/
void sysfs_remove_link(struct kobject * kobj, char * name)
{
sysfs_hash_and_remove(kobj->dentry,name);
}
EXPORT_SYMBOL(sysfs_create_link);
EXPORT_SYMBOL(sysfs_remove_link);
fs/sysfs/sysfs.h 0 → 100644
View file @ f7a5d012
extern struct vfsmount * sysfs_mount;
extern struct inode *sysfs_get_inode(struct super_block *sb, int mode, int dev);
extern int sysfs_mknod(struct inode *, struct dentry *, int, dev_t);
extern struct dentry * sysfs_get_dentry(struct dentry *, char *);
extern void sysfs_hash_and_remove(struct dentry * dir, const char * name);
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