/*
- * file.c - operations for regular (text) files.
+ * fs/sysfs/file.c - sysfs regular (text) file implementation
+ *
+ * Copyright (c) 2001-3 Patrick Mochel
+ * Copyright (c) 2007 SUSE Linux Products GmbH
+ * Copyright (c) 2007 Tejun Heo <teheo@suse.de>
+ *
+ * This file is released under the GPLv2.
+ *
+ * Please see Documentation/filesystems/sysfs.txt for more information.
*/
#include <linux/module.h>
#include <linux/kobject.h>
+#include <linux/kallsyms.h>
+#include <linux/slab.h>
+#include <linux/fsnotify.h>
#include <linux/namei.h>
#include <linux/poll.h>
#include <linux/list.h>
#include <linux/mutex.h>
+#include <linux/limits.h>
#include <asm/uaccess.h>
#include "sysfs.h"
-#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)
+/* used in crash dumps to help with debugging */
+static char last_sysfs_file[PATH_MAX];
+void sysfs_printk_last_file(void)
{
- struct kset *kset = to_kset(kobj);
- struct subsys_attribute * sattr = to_sattr(attr);
- ssize_t ret = -EIO;
-
- if (sattr->show)
- ret = sattr->show(kset, page);
- return ret;
-}
-
-static ssize_t
-subsys_attr_store(struct kobject * kobj, struct attribute * attr,
- const char * page, size_t count)
-{
- struct kset *kset = to_kset(kobj);
- struct subsys_attribute * sattr = to_sattr(attr);
- ssize_t ret = -EIO;
-
- if (sattr->store)
- ret = sattr->store(kset, page, count);
- return ret;
+ printk(KERN_EMERG "last sysfs file: %s\n", last_sysfs_file);
}
-static struct sysfs_ops subsys_sysfs_ops = {
- .show = subsys_attr_show,
- .store = subsys_attr_store,
-};
-
/*
* There's one sysfs_buffer for each open file and one
* sysfs_open_dirent for each sysfs_dirent with one or more open
* sysfs_dirent->s_attr.open points to sysfs_open_dirent. s_attr.open
* is protected by sysfs_open_dirent_lock.
*/
-static spinlock_t sysfs_open_dirent_lock = SPIN_LOCK_UNLOCKED;
+static DEFINE_SPINLOCK(sysfs_open_dirent_lock);
struct sysfs_open_dirent {
atomic_t refcnt;
+ atomic_t event;
+ wait_queue_head_t poll;
struct list_head buffers; /* goes through sysfs_buffer.list */
};
if (!sysfs_get_active_two(attr_sd))
return -ENODEV;
- buffer->event = atomic_read(&attr_sd->s_event);
+ buffer->event = atomic_read(&attr_sd->s_attr.open->event);
count = ops->show(kobj, attr_sd->s_attr.attr, buffer->page);
sysfs_put_active_two(attr_sd);
- BUG_ON(count > (ssize_t)PAGE_SIZE);
+ /*
+ * The code works fine with PAGE_SIZE return but it's likely to
+ * indicate truncated result or overflow in normal use cases.
+ */
+ if (count >= (ssize_t)PAGE_SIZE) {
+ print_symbol("fill_read_buffer: %s returned bad count\n",
+ (unsigned long)ops->show);
+ /* Try to struggle along */
+ count = PAGE_SIZE - 1;
+ }
if (count >= 0) {
buffer->needs_read_fill = 0;
buffer->count = count;
ssize_t retval = 0;
mutex_lock(&buffer->mutex);
- if (buffer->needs_read_fill) {
+ if (buffer->needs_read_fill || *ppos == 0) {
retval = fill_read_buffer(file->f_path.dentry,buffer);
if (retval)
goto out;
}
pr_debug("%s: count = %zd, ppos = %lld, buf = %s\n",
- __FUNCTION__, count, *ppos, buffer->page);
+ __func__, count, *ppos, buffer->page);
retval = simple_read_from_buffer(buf, count, ppos, buffer->page,
buffer->count);
out:
return -ENOMEM;
atomic_set(&new_od->refcnt, 0);
+ atomic_set(&new_od->event, 1);
+ init_waitqueue_head(&new_od->poll);
INIT_LIST_HEAD(&new_od->buffers);
goto retry;
}
{
struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
- struct sysfs_buffer * buffer;
- struct sysfs_ops * ops = NULL;
- int error;
+ struct sysfs_buffer *buffer;
+ struct sysfs_ops *ops;
+ int error = -EACCES;
+ char *p;
+
+ p = d_path(&file->f_path, last_sysfs_file, sizeof(last_sysfs_file));
+ if (p)
+ memmove(last_sysfs_file, p, strlen(p) + 1);
/* need attr_sd for attr and ops, its parent for kobj */
if (!sysfs_get_active_two(attr_sd))
return -ENODEV;
- /* 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)
+ /* every kobject with an attribute needs a ktype assigned */
+ if (kobj->ktype && kobj->ktype->sysfs_ops)
ops = kobj->ktype->sysfs_ops;
- else
- ops = &subsys_sysfs_ops;
-
- error = -EACCES;
-
- /* No sysfs operations, either from having no subsystem,
- * or the subsystem have no operations.
- */
- if (!ops)
+ else {
+ WARN(1, KERN_ERR "missing sysfs attribute operations for "
+ "kobject: %s\n", kobject_name(kobj));
goto err_out;
+ }
/* File needs write support.
* The inode's perms must say it's ok,
* 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'.
+ * need to close and re-open the file, or seek to 0 and read again.
* 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 (Neither 'poll' nor 'select' return
{
struct sysfs_buffer * buffer = filp->private_data;
struct sysfs_dirent *attr_sd = filp->f_path.dentry->d_fsdata;
- struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
+ struct sysfs_open_dirent *od = attr_sd->s_attr.open;
/* need parent for the kobj, grab both */
if (!sysfs_get_active_two(attr_sd))
goto trigger;
- poll_wait(filp, &kobj->poll, wait);
+ poll_wait(filp, &od->poll, wait);
sysfs_put_active_two(attr_sd);
- if (buffer->event != atomic_read(&attr_sd->s_event))
+ if (buffer->event != atomic_read(&od->event))
goto trigger;
return 0;
return POLLERR|POLLPRI;
}
-void sysfs_notify(struct kobject *k, char *dir, char *attr)
+void sysfs_notify_dirent(struct sysfs_dirent *sd)
+{
+ struct sysfs_open_dirent *od;
+
+ spin_lock(&sysfs_open_dirent_lock);
+
+ od = sd->s_attr.open;
+ if (od) {
+ atomic_inc(&od->event);
+ wake_up_interruptible(&od->poll);
+ }
+
+ spin_unlock(&sysfs_open_dirent_lock);
+}
+EXPORT_SYMBOL_GPL(sysfs_notify_dirent);
+
+void sysfs_notify(struct kobject *k, const char *dir, const char *attr)
{
struct sysfs_dirent *sd = k->sd;
sd = sysfs_find_dirent(sd, dir);
if (sd && attr)
sd = sysfs_find_dirent(sd, attr);
- if (sd) {
- atomic_inc(&sd->s_event);
- wake_up_interruptible(&k->poll);
- }
+ if (sd)
+ sysfs_notify_dirent(sd);
mutex_unlock(&sysfs_mutex);
}
.poll = sysfs_poll,
};
-
-int sysfs_add_file(struct sysfs_dirent *dir_sd, const struct attribute *attr,
- int type)
+int sysfs_add_file_mode(struct sysfs_dirent *dir_sd,
+ const struct attribute *attr, int type, mode_t amode)
{
- umode_t mode = (attr->mode & S_IALLUGO) | S_IFREG;
+ umode_t mode = (amode & S_IALLUGO) | S_IFREG;
struct sysfs_addrm_cxt acxt;
struct sysfs_dirent *sd;
int rc;
}
+int sysfs_add_file(struct sysfs_dirent *dir_sd, const struct attribute *attr,
+ int type)
+{
+ return sysfs_add_file_mode(dir_sd, attr, type, attr->mode);
+}
+
+
/**
* sysfs_create_file - create an attribute file for an object.
* @kobj: object we're creating for.
- * @attr: atrribute descriptor.
+ * @attr: attribute descriptor.
*/
int sysfs_create_file(struct kobject * kobj, const struct attribute * attr)
struct sysfs_dirent *dir_sd;
int error;
- dir_sd = sysfs_get_dirent(kobj->sd, group);
+ if (group)
+ dir_sd = sysfs_get_dirent(kobj->sd, group);
+ else
+ dir_sd = sysfs_get(kobj->sd);
+
if (!dir_sd)
return -ENOENT;
newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
- rc = notify_change(victim, &newattrs);
+ newattrs.ia_ctime = current_fs_time(inode->i_sb);
+ rc = sysfs_setattr(victim, &newattrs);
if (rc == 0) {
+ fsnotify_change(victim, newattrs.ia_valid);
mutex_lock(&sysfs_mutex);
victim_sd->s_mode = newattrs.ia_mode;
mutex_unlock(&sysfs_mutex);
{
struct sysfs_dirent *dir_sd;
- dir_sd = sysfs_get_dirent(kobj->sd, group);
+ if (group)
+ dir_sd = sysfs_get_dirent(kobj->sd, group);
+ else
+ dir_sd = sysfs_get(kobj->sd);
if (dir_sd) {
sysfs_hash_and_remove(dir_sd, attr->name);
sysfs_put(dir_sd);
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff