*/
#include <linux/module.h>
-#include <linux/dnotify.h>
+#include <linux/fsnotify.h>
#include <linux/kobject.h>
+#include <linux/namei.h>
+#include <linux/poll.h>
+#include <linux/limits.h>
#include <asm/uaccess.h>
+#include <asm/semaphore.h>
#include "sysfs.h"
-static struct file_operations sysfs_file_operations;
-
-static int init_file(struct inode * inode)
-{
- inode->i_size = PAGE_SIZE;
- inode->i_fop = &sysfs_file_operations;
- return 0;
-}
-
#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.
{
struct subsystem * s = to_subsys(kobj);
struct subsys_attribute * sattr = to_sattr(attr);
- ssize_t ret = 0;
+ ssize_t ret = -EIO;
if (sattr->show)
ret = sattr->show(s,page);
{
struct subsystem * s = to_subsys(kobj);
struct subsys_attribute * sattr = to_sattr(attr);
- ssize_t ret = 0;
+ ssize_t ret = -EIO;
if (sattr->store)
ret = sattr->store(s,page,count);
loff_t pos;
char * page;
struct sysfs_ops * ops;
+ struct semaphore sem;
+ int needs_read_fill;
+ int event;
};
/**
* fill_read_buffer - allocate and fill buffer from object.
- * @file: file pointer.
+ * @dentry: dentry pointer.
* @buffer: data buffer for file.
*
* Allocate @buffer->page, if it hasn't been already, then call the
* data.
* This is called only once, on the file's first read.
*/
-static int fill_read_buffer(struct file * file, struct sysfs_buffer * buffer)
+static int fill_read_buffer(struct dentry * dentry, struct sysfs_buffer * buffer)
{
- struct attribute * attr = file->f_dentry->d_fsdata;
- struct kobject * kobj = file->f_dentry->d_parent->d_fsdata;
+ struct sysfs_dirent * sd = dentry->d_fsdata;
+ struct attribute * attr = to_attr(dentry);
+ struct kobject * kobj = to_kobj(dentry->d_parent);
struct sysfs_ops * ops = buffer->ops;
int ret = 0;
ssize_t count;
if (!buffer->page)
return -ENOMEM;
+ buffer->event = atomic_read(&sd->s_event);
count = ops->show(kobj,attr,buffer->page);
+ buffer->needs_read_fill = 0;
+ BUG_ON(count > (ssize_t)PAGE_SIZE);
if (count >= 0)
buffer->count = count;
else
/**
* flush_read_buffer - push buffer to userspace.
* @buffer: data buffer for file.
- * @userbuf: user-passed buffer.
+ * @buf: user-passed buffer.
* @count: number of bytes requested.
* @ppos: file position.
*
{
int error;
+ if (*ppos > buffer->count)
+ return 0;
+
if (count > (buffer->count - *ppos))
count = buffer->count - *ppos;
struct sysfs_buffer * buffer = file->private_data;
ssize_t retval = 0;
- if (!*ppos) {
- if ((retval = fill_read_buffer(file,buffer)))
- return retval;
+ down(&buffer->sem);
+ if (buffer->needs_read_fill) {
+ if ((retval = fill_read_buffer(file->f_path.dentry,buffer)))
+ goto out;
}
- pr_debug("%s: count = %d, ppos = %lld, buf = %s\n",
- __FUNCTION__,count,*ppos,buffer->page);
- return flush_read_buffer(buffer,buf,count,ppos);
+ pr_debug("%s: count = %zd, ppos = %lld, buf = %s\n",
+ __FUNCTION__, count, *ppos, buffer->page);
+ retval = flush_read_buffer(buffer,buf,count,ppos);
+out:
+ up(&buffer->sem);
+ return retval;
}
/**
* 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
if (count >= PAGE_SIZE)
count = PAGE_SIZE - 1;
error = copy_from_user(buffer->page,buf,count);
+ buffer->needs_read_fill = 1;
+ /* if buf is assumed to contain a string, terminate it by \0,
+ so e.g. sscanf() can scan the string easily */
+ buffer->page[count] = 0;
return error ? -EFAULT : count;
}
/**
* flush_write_buffer - push buffer to kobject.
- * @file: file pointer.
+ * @dentry: dentry to the attribute
* @buffer: data buffer for file.
+ * @count: number of bytes
*
* Get the correct pointers for the kobject and the attribute we're
* dealing with, then call the store() method for the attribute,
*/
static int
-flush_write_buffer(struct file * file, struct sysfs_buffer * buffer, size_t count)
+flush_write_buffer(struct dentry * dentry, 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 attribute * attr = to_attr(dentry);
+ struct kobject * kobj = to_kobj(dentry->d_parent);
struct sysfs_ops * ops = buffer->ops;
return ops->store(kobj,attr,buffer->page,count);
sysfs_write_file(struct file *file, const char __user *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;
+ ssize_t len;
+
+ down(&buffer->sem);
+ len = fill_write_buffer(buffer, buf, count);
+ if (len > 0)
+ len = flush_write_buffer(file->f_path.dentry, buffer, len);
+ if (len > 0)
+ *ppos += len;
+ up(&buffer->sem);
+ return len;
}
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 kobject *kobj = sysfs_get_kobject(file->f_path.dentry->d_parent);
+ struct attribute * attr = to_attr(file->f_path.dentry);
struct sysfs_buffer * buffer;
struct sysfs_ops * ops = NULL;
int error = 0;
/* 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);
+ buffer = kzalloc(sizeof(struct sysfs_buffer), GFP_KERNEL);
if (buffer) {
- memset(buffer,0,sizeof(struct sysfs_buffer));
+ init_MUTEX(&buffer->sem);
+ buffer->needs_read_fill = 1;
buffer->ops = ops;
file->private_data = buffer;
} else
return error;
}
+char last_sysfs_file[PATH_MAX];
+
static int sysfs_open_file(struct inode * inode, struct file * filp)
{
+ char *p = d_path(filp->f_dentry, sysfs_mount, last_sysfs_file,
+ sizeof(last_sysfs_file));
+ if (p)
+ memmove(last_sysfs_file, p, strlen(p) + 1);
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 attribute * attr = filp->f_dentry->d_fsdata;
+ struct kobject * kobj = to_kobj(filp->f_path.dentry->d_parent);
+ struct attribute * attr = to_attr(filp->f_path.dentry);
+ struct module * owner = attr->owner;
struct sysfs_buffer * buffer = filp->private_data;
if (kobj)
kobject_put(kobj);
- module_put(attr->owner);
+ /* After this point, attr should not be accessed. */
+ module_put(owner);
if (buffer) {
if (buffer->page)
return 0;
}
-static struct file_operations sysfs_file_operations = {
+/* Sysfs attribute files are pollable. The idea is that you read
+ * the content and then you use 'poll' or 'select' to wait for
+ * the content to change. When the content changes (assuming the
+ * manager for the kobject supports notification), poll will
+ * return POLLERR|POLLPRI, and select will return the fd whether
+ * it is waiting for read, write, or exceptions.
+ * Once poll/select indicates that the value has changed, you
+ * need to close and re-open the file, as simply seeking and reading
+ * again will not get new data, or reset the state of 'poll'.
+ * Reminder: this only works for attributes which actively support
+ * it, and it is not possible to test an attribute from userspace
+ * to see if it supports poll (Nether 'poll' or 'select' return
+ * an appropriate error code). When in doubt, set a suitable timeout value.
+ */
+static unsigned int sysfs_poll(struct file *filp, poll_table *wait)
+{
+ struct sysfs_buffer * buffer = filp->private_data;
+ struct kobject * kobj = to_kobj(filp->f_path.dentry->d_parent);
+ struct sysfs_dirent * sd = filp->f_path.dentry->d_fsdata;
+ int res = 0;
+
+ poll_wait(filp, &kobj->poll, wait);
+
+ if (buffer->event != atomic_read(&sd->s_event)) {
+ res = POLLERR|POLLPRI;
+ buffer->needs_read_fill = 1;
+ }
+
+ return res;
+}
+
+
+static struct dentry *step_down(struct dentry *dir, const char * name)
+{
+ struct dentry * de;
+
+ if (dir == NULL || dir->d_inode == NULL)
+ return NULL;
+
+ mutex_lock(&dir->d_inode->i_mutex);
+ de = lookup_one_len(name, dir, strlen(name));
+ mutex_unlock(&dir->d_inode->i_mutex);
+ dput(dir);
+ if (IS_ERR(de))
+ return NULL;
+ if (de->d_inode == NULL) {
+ dput(de);
+ return NULL;
+ }
+ return de;
+}
+
+void sysfs_notify(struct kobject * k, char *dir, char *attr)
+{
+ struct dentry *de = k->dentry;
+ if (de)
+ dget(de);
+ if (de && dir)
+ de = step_down(de, dir);
+ if (de && attr)
+ de = step_down(de, attr);
+ if (de) {
+ struct sysfs_dirent * sd = de->d_fsdata;
+ if (sd)
+ atomic_inc(&sd->s_event);
+ wake_up_interruptible(&k->poll);
+ dput(de);
+ }
+}
+EXPORT_SYMBOL_GPL(sysfs_notify);
+
+const 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,
+ .poll = sysfs_poll,
};
-int sysfs_add_file(struct dentry * dir, const struct attribute * attr)
+int sysfs_add_file(struct dentry * dir, const struct attribute * attr, int type)
{
- struct dentry * dentry;
- int error;
+ struct sysfs_dirent * parent_sd = dir->d_fsdata;
+ umode_t mode = (attr->mode & S_IALLUGO) | S_IFREG;
+ int error = -EEXIST;
+
+ mutex_lock(&dir->d_inode->i_mutex);
+ if (!sysfs_dirent_exist(parent_sd, attr->name))
+ error = sysfs_make_dirent(parent_sd, NULL, (void *)attr,
+ mode, type);
+ mutex_unlock(&dir->d_inode->i_mutex);
- down(&dir->d_inode->i_sem);
- dentry = sysfs_get_dentry(dir,attr->name);
- if (!IS_ERR(dentry)) {
- error = sysfs_create(dentry,
- (attr->mode & S_IALLUGO) | S_IFREG,
- init_file);
- if (!error)
- dentry->d_fsdata = (void *)attr;
- dput(dentry);
- } else
- error = PTR_ERR(dentry);
- up(&dir->d_inode->i_sem);
return error;
}
int sysfs_create_file(struct kobject * kobj, const struct attribute * attr)
{
- if (kobj && attr)
- return sysfs_add_file(kobj->dentry,attr);
- return -EINVAL;
+ BUG_ON(!kobj || !kobj->dentry || !attr);
+
+ return sysfs_add_file(kobj->dentry, attr, SYSFS_KOBJ_ATTR);
+
}
* 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, const struct attribute * attr)
{
struct dentry * victim;
int res = -ENOENT;
- down(&dir->d_inode->i_sem);
- victim = sysfs_get_dentry(dir, attr->name);
+ mutex_lock(&dir->d_inode->i_mutex);
+ victim = lookup_one_len(attr->name, dir, strlen(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);
+ fsnotify_modify(victim);
res = 0;
- }
+ } else
+ d_drop(victim);
/**
- * Drop the reference acquired from sysfs_get_dentry() above.
+ * Drop the reference acquired from lookup_one_len() above.
*/
dput(victim);
}
- up(&dir->d_inode->i_sem);
+ mutex_unlock(&dir->d_inode->i_mutex);
return res;
}
+/**
+ * sysfs_chmod_file - update the modified mode value on an object attribute.
+ * @kobj: object we're acting for.
+ * @attr: attribute descriptor.
+ * @mode: file permissions.
+ *
+ */
+int sysfs_chmod_file(struct kobject *kobj, struct attribute *attr, mode_t mode)
+{
+ struct dentry *dir = kobj->dentry;
+ struct dentry *victim;
+ struct inode * inode;
+ struct iattr newattrs;
+ int res = -ENOENT;
+
+ mutex_lock(&dir->d_inode->i_mutex);
+ victim = lookup_one_len(attr->name, dir, strlen(attr->name));
+ if (!IS_ERR(victim)) {
+ if (victim->d_inode &&
+ (victim->d_parent->d_inode == dir->d_inode)) {
+ inode = victim->d_inode;
+ mutex_lock(&inode->i_mutex);
+ newattrs.ia_mode = (mode & S_IALLUGO) |
+ (inode->i_mode & ~S_IALLUGO);
+ newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
+ res = notify_change(victim, &newattrs);
+ mutex_unlock(&inode->i_mutex);
+ }
+ dput(victim);
+ }
+ mutex_unlock(&dir->d_inode->i_mutex);
+
+ return res;
+}
+EXPORT_SYMBOL_GPL(sysfs_chmod_file);
+
+
/**
* sysfs_remove_file - remove an object attribute.
* @kobj: object we're acting for.
}
-EXPORT_SYMBOL(sysfs_create_file);
-EXPORT_SYMBOL(sysfs_remove_file);
-EXPORT_SYMBOL(sysfs_update_file);
-
+EXPORT_SYMBOL_GPL(sysfs_create_file);
+EXPORT_SYMBOL_GPL(sysfs_remove_file);
+EXPORT_SYMBOL_GPL(sysfs_update_file);
git://git.onelab.eu / linux-2.6.git / blobdiff