#undef DEBUG
- #include <linux/list.h>
- #include <linux/init.h>
#include <linux/pagemap.h>
- #include <linux/stat.h>
- #include <linux/fs.h>
- #include <linux/dcache.h>
#include <linux/namei.h>
- #include <linux/module.h>
- #include <linux/slab.h>
#include <linux/backing-dev.h>
- #include <linux/kobject.h>
- #include <linux/mount.h>
- #include <linux/dnotify.h>
- #include <asm/uaccess.h>
-
+ extern struct super_block * sysfs_sb;
- /* Random magic number */
- #define SYSFS_MAGIC 0x62656572
-
- 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 address_space_operations sysfs_aops = {
+ .readpage = simple_readpage,
+ .prepare_write = simple_prepare_write,
+ .commit_write = simple_commit_write
+ };
static struct backing_dev_info sysfs_backing_dev_info = {
.ra_pages = 0, /* No readahead */
return inode;
}
- static int sysfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
+ int sysfs_create(struct dentry * dentry, int mode, int (*init)(struct inode *))
{
- struct inode *inode;
int error = 0;
-
+ struct inode * inode = NULL;
- } else
+ if (dentry) {
+ if (!dentry->d_inode) {
+ if ((inode = sysfs_new_inode(mode)))
+ goto Proceed;
+ else
+ error = -ENOMEM;
+ error = -EEXIST;
+ } else
+ error = -ENOENT;
+ goto Done;
- if (!dentry->d_inode) {
- inode = sysfs_get_inode(dir->i_sb, mode, dev);
- if (inode)
- d_instantiate(dentry, inode);
- else
- error = -ENOSPC;
- } else
- error = -EEXIST;
- return error;
- }
-
- 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;
- }
-
- 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;
- ssize_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);
+ Proceed:
+ if (init)
+ error = init(inode);
- if (!error) {
+ 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;
+ d_instantiate(dentry, inode);
- dget(dentry);
- } else
+ 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;
+ iput(inode);
Done:
- if (error && kobj)
- kobject_put(kobj);
return error;
}
pr_debug("sysfs: Removing %s (%d)\n", victim->d_name.name,
atomic_read(&victim->d_count));
- }
-
- /**
- * Drop the reference acquired from get_dentry() above.
- */
- dput(victim);
- }
- 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().
+ * Drop reference from initial sysfs_get_dentry().
*/
dput(victim);
- res = 0;
}
/**
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;
- 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);
-
- spin_lock(&dcache_lock);
- node = dentry->d_subdirs.next;
- while (node != &dentry->d_subdirs) {
- struct dentry * d = list_entry(node,struct dentry,d_child);
- list_del_init(node);
-
- pr_debug(" o %s (%d): ",d->d_name.name,atomic_read(&d->d_count));
- if (d->d_inode) {
- d = dget_locked(d);
- pr_debug("removing");
-
- /**
- * Unlink and unhash.
- */
- spin_unlock(&dcache_lock);
- d_delete(d);
- simple_unlink(dentry->d_inode,d);
- dput(d);
- spin_lock(&dcache_lock);
- }
- pr_debug(" done\n");
-
- node = dentry->d_subdirs.next;
- }
- spin_unlock(&dcache_lock);
-
- 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_update_file);
- EXPORT_SYMBOL(sysfs_remove_file);
- EXPORT_SYMBOL(sysfs_create_link);
- EXPORT_SYMBOL(sysfs_remove_link);
- EXPORT_SYMBOL(sysfs_create_dir);
- EXPORT_SYMBOL(sysfs_remove_dir);
+
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