Contributors: 42
| Author |
Tokens |
Token Proportion |
Commits |
Commit Proportion |
| Tejun Heo |
1286 |
40.86% |
43 |
36.75% |
| Christian Brauner |
311 |
9.88% |
3 |
2.56% |
| Patrick Mochel |
222 |
7.05% |
9 |
7.69% |
| Neil Brown |
209 |
6.64% |
7 |
5.98% |
| Joe Perches |
164 |
5.21% |
1 |
0.85% |
| Alan Stern |
124 |
3.94% |
2 |
1.71% |
| Christoph Hellwig |
112 |
3.56% |
4 |
3.42% |
| Andi Kleen |
112 |
3.56% |
1 |
0.85% |
| Dmitry Torokhov |
97 |
3.08% |
3 |
2.56% |
| Kay Sievers |
91 |
2.89% |
1 |
0.85% |
| Andrew Morton |
68 |
2.16% |
5 |
4.27% |
| Bart Van Assche |
60 |
1.91% |
1 |
0.85% |
| Lukas Wunner |
43 |
1.37% |
1 |
0.85% |
| Valentine Sinitsyn |
42 |
1.33% |
1 |
0.85% |
| Greg Kroah-Hartman |
32 |
1.02% |
4 |
3.42% |
| Maneesh Soni |
32 |
1.02% |
1 |
0.85% |
| Konstantin Khlebnikov |
30 |
0.95% |
1 |
0.85% |
| James Bottomley |
28 |
0.89% |
2 |
1.71% |
| Daniel Vetter |
26 |
0.83% |
1 |
0.85% |
| Ming Lei |
6 |
0.19% |
1 |
0.85% |
| Jack Wang |
5 |
0.16% |
1 |
0.85% |
| Eric W. Biedermann |
4 |
0.13% |
1 |
0.85% |
| Rusty Russell |
4 |
0.13% |
1 |
0.85% |
| Randy Dunlap |
4 |
0.13% |
1 |
0.85% |
| Oliver Neukum |
3 |
0.10% |
1 |
0.85% |
| Al Viro |
3 |
0.10% |
2 |
1.71% |
| Krzysztof Wilczynski |
3 |
0.10% |
2 |
1.71% |
| Vladimir Zapolskiy |
3 |
0.10% |
2 |
1.71% |
| Robert P. J. Day |
3 |
0.10% |
1 |
0.85% |
| Emese Revfy |
2 |
0.06% |
1 |
0.85% |
| Jani Nikula |
2 |
0.06% |
1 |
0.85% |
| Sergey Senozhatsky |
2 |
0.06% |
1 |
0.85% |
| Jun'ichi Nomura |
2 |
0.06% |
1 |
0.85% |
| Miao Xie |
2 |
0.06% |
1 |
0.85% |
| Trent Piepho |
2 |
0.06% |
1 |
0.85% |
| Linus Torvalds |
2 |
0.06% |
1 |
0.85% |
| Miklos Szeredi |
1 |
0.03% |
1 |
0.85% |
| Mauro Carvalho Chehab |
1 |
0.03% |
1 |
0.85% |
| Tyler Hicks |
1 |
0.03% |
1 |
0.85% |
| Benjamin Herrenschmidt |
1 |
0.03% |
1 |
0.85% |
| Yang Ruirui |
1 |
0.03% |
1 |
0.85% |
| Jean Delvare |
1 |
0.03% |
1 |
0.85% |
| Total |
3147 |
|
117 |
|
// SPDX-License-Identifier: GPL-2.0
/*
* 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>
*
* Please see Documentation/filesystems/sysfs.rst for more information.
*/
#include <linux/module.h>
#include <linux/kobject.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/seq_file.h>
#include <linux/mm.h>
#include "sysfs.h"
/*
* Determine ktype->sysfs_ops for the given kernfs_node. This function
* must be called while holding an active reference.
*/
static const struct sysfs_ops *sysfs_file_ops(struct kernfs_node *kn)
{
struct kobject *kobj = kn->parent->priv;
if (kn->flags & KERNFS_LOCKDEP)
lockdep_assert_held(kn);
return kobj->ktype ? kobj->ktype->sysfs_ops : NULL;
}
/*
* Reads on sysfs are handled through seq_file, which takes care of hairy
* details like buffering and seeking. The following function pipes
* sysfs_ops->show() result through seq_file.
*/
static int sysfs_kf_seq_show(struct seq_file *sf, void *v)
{
struct kernfs_open_file *of = sf->private;
struct kobject *kobj = of->kn->parent->priv;
const struct sysfs_ops *ops = sysfs_file_ops(of->kn);
ssize_t count;
char *buf;
if (WARN_ON_ONCE(!ops->show))
return -EINVAL;
/* acquire buffer and ensure that it's >= PAGE_SIZE and clear */
count = seq_get_buf(sf, &buf);
if (count < PAGE_SIZE) {
seq_commit(sf, -1);
return 0;
}
memset(buf, 0, PAGE_SIZE);
count = ops->show(kobj, of->kn->priv, buf);
if (count < 0)
return count;
/*
* 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) {
printk("fill_read_buffer: %pS returned bad count\n",
ops->show);
/* Try to struggle along */
count = PAGE_SIZE - 1;
}
seq_commit(sf, count);
return 0;
}
static ssize_t sysfs_kf_bin_read(struct kernfs_open_file *of, char *buf,
size_t count, loff_t pos)
{
struct bin_attribute *battr = of->kn->priv;
struct kobject *kobj = of->kn->parent->priv;
loff_t size = file_inode(of->file)->i_size;
if (!count)
return 0;
if (size) {
if (pos >= size)
return 0;
if (pos + count > size)
count = size - pos;
}
if (!battr->read)
return -EIO;
return battr->read(of->file, kobj, battr, buf, pos, count);
}
/* kernfs read callback for regular sysfs files with pre-alloc */
static ssize_t sysfs_kf_read(struct kernfs_open_file *of, char *buf,
size_t count, loff_t pos)
{
const struct sysfs_ops *ops = sysfs_file_ops(of->kn);
struct kobject *kobj = of->kn->parent->priv;
ssize_t len;
/*
* If buf != of->prealloc_buf, we don't know how
* large it is, so cannot safely pass it to ->show
*/
if (WARN_ON_ONCE(buf != of->prealloc_buf))
return 0;
len = ops->show(kobj, of->kn->priv, buf);
if (len < 0)
return len;
if (pos) {
if (len <= pos)
return 0;
len -= pos;
memmove(buf, buf + pos, len);
}
return min_t(ssize_t, count, len);
}
/* kernfs write callback for regular sysfs files */
static ssize_t sysfs_kf_write(struct kernfs_open_file *of, char *buf,
size_t count, loff_t pos)
{
const struct sysfs_ops *ops = sysfs_file_ops(of->kn);
struct kobject *kobj = of->kn->parent->priv;
if (!count)
return 0;
return ops->store(kobj, of->kn->priv, buf, count);
}
/* kernfs write callback for bin sysfs files */
static ssize_t sysfs_kf_bin_write(struct kernfs_open_file *of, char *buf,
size_t count, loff_t pos)
{
struct bin_attribute *battr = of->kn->priv;
struct kobject *kobj = of->kn->parent->priv;
loff_t size = file_inode(of->file)->i_size;
if (size) {
if (size <= pos)
return -EFBIG;
count = min_t(ssize_t, count, size - pos);
}
if (!count)
return 0;
if (!battr->write)
return -EIO;
return battr->write(of->file, kobj, battr, buf, pos, count);
}
static int sysfs_kf_bin_mmap(struct kernfs_open_file *of,
struct vm_area_struct *vma)
{
struct bin_attribute *battr = of->kn->priv;
struct kobject *kobj = of->kn->parent->priv;
return battr->mmap(of->file, kobj, battr, vma);
}
static loff_t sysfs_kf_bin_llseek(struct kernfs_open_file *of, loff_t offset,
int whence)
{
struct bin_attribute *battr = of->kn->priv;
struct kobject *kobj = of->kn->parent->priv;
if (battr->llseek)
return battr->llseek(of->file, kobj, battr, offset, whence);
else
return generic_file_llseek(of->file, offset, whence);
}
static int sysfs_kf_bin_open(struct kernfs_open_file *of)
{
struct bin_attribute *battr = of->kn->priv;
if (battr->f_mapping)
of->file->f_mapping = battr->f_mapping();
return 0;
}
void sysfs_notify(struct kobject *kobj, const char *dir, const char *attr)
{
struct kernfs_node *kn = kobj->sd, *tmp;
if (kn && dir)
kn = kernfs_find_and_get(kn, dir);
else
kernfs_get(kn);
if (kn && attr) {
tmp = kernfs_find_and_get(kn, attr);
kernfs_put(kn);
kn = tmp;
}
if (kn) {
kernfs_notify(kn);
kernfs_put(kn);
}
}
EXPORT_SYMBOL_GPL(sysfs_notify);
static const struct kernfs_ops sysfs_file_kfops_empty = {
};
static const struct kernfs_ops sysfs_file_kfops_ro = {
.seq_show = sysfs_kf_seq_show,
};
static const struct kernfs_ops sysfs_file_kfops_wo = {
.write = sysfs_kf_write,
};
static const struct kernfs_ops sysfs_file_kfops_rw = {
.seq_show = sysfs_kf_seq_show,
.write = sysfs_kf_write,
};
static const struct kernfs_ops sysfs_prealloc_kfops_ro = {
.read = sysfs_kf_read,
.prealloc = true,
};
static const struct kernfs_ops sysfs_prealloc_kfops_wo = {
.write = sysfs_kf_write,
.prealloc = true,
};
static const struct kernfs_ops sysfs_prealloc_kfops_rw = {
.read = sysfs_kf_read,
.write = sysfs_kf_write,
.prealloc = true,
};
static const struct kernfs_ops sysfs_bin_kfops_ro = {
.read = sysfs_kf_bin_read,
};
static const struct kernfs_ops sysfs_bin_kfops_wo = {
.write = sysfs_kf_bin_write,
};
static const struct kernfs_ops sysfs_bin_kfops_rw = {
.read = sysfs_kf_bin_read,
.write = sysfs_kf_bin_write,
};
static const struct kernfs_ops sysfs_bin_kfops_mmap = {
.read = sysfs_kf_bin_read,
.write = sysfs_kf_bin_write,
.mmap = sysfs_kf_bin_mmap,
.open = sysfs_kf_bin_open,
.llseek = sysfs_kf_bin_llseek,
};
int sysfs_add_file_mode_ns(struct kernfs_node *parent,
const struct attribute *attr, umode_t mode, kuid_t uid,
kgid_t gid, const void *ns)
{
struct kobject *kobj = parent->priv;
const struct sysfs_ops *sysfs_ops = kobj->ktype->sysfs_ops;
struct lock_class_key *key = NULL;
const struct kernfs_ops *ops = NULL;
struct kernfs_node *kn;
/* every kobject with an attribute needs a ktype assigned */
if (WARN(!sysfs_ops, KERN_ERR
"missing sysfs attribute operations for kobject: %s\n",
kobject_name(kobj)))
return -EINVAL;
if (mode & SYSFS_PREALLOC) {
if (sysfs_ops->show && sysfs_ops->store)
ops = &sysfs_prealloc_kfops_rw;
else if (sysfs_ops->show)
ops = &sysfs_prealloc_kfops_ro;
else if (sysfs_ops->store)
ops = &sysfs_prealloc_kfops_wo;
} else {
if (sysfs_ops->show && sysfs_ops->store)
ops = &sysfs_file_kfops_rw;
else if (sysfs_ops->show)
ops = &sysfs_file_kfops_ro;
else if (sysfs_ops->store)
ops = &sysfs_file_kfops_wo;
}
if (!ops)
ops = &sysfs_file_kfops_empty;
#ifdef CONFIG_DEBUG_LOCK_ALLOC
if (!attr->ignore_lockdep)
key = attr->key ?: (struct lock_class_key *)&attr->skey;
#endif
kn = __kernfs_create_file(parent, attr->name, mode & 0777, uid, gid,
PAGE_SIZE, ops, (void *)attr, ns, key);
if (IS_ERR(kn)) {
if (PTR_ERR(kn) == -EEXIST)
sysfs_warn_dup(parent, attr->name);
return PTR_ERR(kn);
}
return 0;
}
int sysfs_add_bin_file_mode_ns(struct kernfs_node *parent,
const struct bin_attribute *battr, umode_t mode,
kuid_t uid, kgid_t gid, const void *ns)
{
const struct attribute *attr = &battr->attr;
struct lock_class_key *key = NULL;
const struct kernfs_ops *ops;
struct kernfs_node *kn;
if (battr->mmap)
ops = &sysfs_bin_kfops_mmap;
else if (battr->read && battr->write)
ops = &sysfs_bin_kfops_rw;
else if (battr->read)
ops = &sysfs_bin_kfops_ro;
else if (battr->write)
ops = &sysfs_bin_kfops_wo;
else
ops = &sysfs_file_kfops_empty;
#ifdef CONFIG_DEBUG_LOCK_ALLOC
if (!attr->ignore_lockdep)
key = attr->key ?: (struct lock_class_key *)&attr->skey;
#endif
kn = __kernfs_create_file(parent, attr->name, mode & 0777, uid, gid,
battr->size, ops, (void *)attr, ns, key);
if (IS_ERR(kn)) {
if (PTR_ERR(kn) == -EEXIST)
sysfs_warn_dup(parent, attr->name);
return PTR_ERR(kn);
}
return 0;
}
/**
* sysfs_create_file_ns - create an attribute file for an object with custom ns
* @kobj: object we're creating for
* @attr: attribute descriptor
* @ns: namespace the new file should belong to
*/
int sysfs_create_file_ns(struct kobject *kobj, const struct attribute *attr,
const void *ns)
{
kuid_t uid;
kgid_t gid;
if (WARN_ON(!kobj || !kobj->sd || !attr))
return -EINVAL;
kobject_get_ownership(kobj, &uid, &gid);
return sysfs_add_file_mode_ns(kobj->sd, attr, attr->mode, uid, gid, ns);
}
EXPORT_SYMBOL_GPL(sysfs_create_file_ns);
int sysfs_create_files(struct kobject *kobj, const struct attribute * const *ptr)
{
int err = 0;
int i;
for (i = 0; ptr[i] && !err; i++)
err = sysfs_create_file(kobj, ptr[i]);
if (err)
while (--i >= 0)
sysfs_remove_file(kobj, ptr[i]);
return err;
}
EXPORT_SYMBOL_GPL(sysfs_create_files);
/**
* sysfs_add_file_to_group - add an attribute file to a pre-existing group.
* @kobj: object we're acting for.
* @attr: attribute descriptor.
* @group: group name.
*/
int sysfs_add_file_to_group(struct kobject *kobj,
const struct attribute *attr, const char *group)
{
struct kernfs_node *parent;
kuid_t uid;
kgid_t gid;
int error;
if (group) {
parent = kernfs_find_and_get(kobj->sd, group);
} else {
parent = kobj->sd;
kernfs_get(parent);
}
if (!parent)
return -ENOENT;
kobject_get_ownership(kobj, &uid, &gid);
error = sysfs_add_file_mode_ns(parent, attr, attr->mode, uid, gid,
NULL);
kernfs_put(parent);
return error;
}
EXPORT_SYMBOL_GPL(sysfs_add_file_to_group);
/**
* 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, const struct attribute *attr,
umode_t mode)
{
struct kernfs_node *kn;
struct iattr newattrs;
int rc;
kn = kernfs_find_and_get(kobj->sd, attr->name);
if (!kn)
return -ENOENT;
newattrs.ia_mode = (mode & S_IALLUGO) | (kn->mode & ~S_IALLUGO);
newattrs.ia_valid = ATTR_MODE;
rc = kernfs_setattr(kn, &newattrs);
kernfs_put(kn);
return rc;
}
EXPORT_SYMBOL_GPL(sysfs_chmod_file);
/**
* sysfs_break_active_protection - break "active" protection
* @kobj: The kernel object @attr is associated with.
* @attr: The attribute to break the "active" protection for.
*
* With sysfs, just like kernfs, deletion of an attribute is postponed until
* all active .show() and .store() callbacks have finished unless this function
* is called. Hence this function is useful in methods that implement self
* deletion.
*/
struct kernfs_node *sysfs_break_active_protection(struct kobject *kobj,
const struct attribute *attr)
{
struct kernfs_node *kn;
kobject_get(kobj);
kn = kernfs_find_and_get(kobj->sd, attr->name);
if (kn)
kernfs_break_active_protection(kn);
else
kobject_put(kobj);
return kn;
}
EXPORT_SYMBOL_GPL(sysfs_break_active_protection);
/**
* sysfs_unbreak_active_protection - restore "active" protection
* @kn: Pointer returned by sysfs_break_active_protection().
*
* Undo the effects of sysfs_break_active_protection(). Since this function
* calls kernfs_put() on the kernfs node that corresponds to the 'attr'
* argument passed to sysfs_break_active_protection() that attribute may have
* been removed between the sysfs_break_active_protection() and
* sysfs_unbreak_active_protection() calls, it is not safe to access @kn after
* this function has returned.
*/
void sysfs_unbreak_active_protection(struct kernfs_node *kn)
{
struct kobject *kobj = kn->parent->priv;
kernfs_unbreak_active_protection(kn);
kernfs_put(kn);
kobject_put(kobj);
}
EXPORT_SYMBOL_GPL(sysfs_unbreak_active_protection);
/**
* sysfs_remove_file_ns - remove an object attribute with a custom ns tag
* @kobj: object we're acting for
* @attr: attribute descriptor
* @ns: namespace tag of the file to remove
*
* Hash the attribute name and namespace tag and kill the victim.
*/
void sysfs_remove_file_ns(struct kobject *kobj, const struct attribute *attr,
const void *ns)
{
struct kernfs_node *parent = kobj->sd;
kernfs_remove_by_name_ns(parent, attr->name, ns);
}
EXPORT_SYMBOL_GPL(sysfs_remove_file_ns);
/**
* sysfs_remove_file_self - remove an object attribute from its own method
* @kobj: object we're acting for
* @attr: attribute descriptor
*
* See kernfs_remove_self() for details.
*/
bool sysfs_remove_file_self(struct kobject *kobj, const struct attribute *attr)
{
struct kernfs_node *parent = kobj->sd;
struct kernfs_node *kn;
bool ret;
kn = kernfs_find_and_get(parent, attr->name);
if (WARN_ON_ONCE(!kn))
return false;
ret = kernfs_remove_self(kn);
kernfs_put(kn);
return ret;
}
EXPORT_SYMBOL_GPL(sysfs_remove_file_self);
void sysfs_remove_files(struct kobject *kobj, const struct attribute * const *ptr)
{
int i;
for (i = 0; ptr[i]; i++)
sysfs_remove_file(kobj, ptr[i]);
}
EXPORT_SYMBOL_GPL(sysfs_remove_files);
/**
* sysfs_remove_file_from_group - remove an attribute file from a group.
* @kobj: object we're acting for.
* @attr: attribute descriptor.
* @group: group name.
*/
void sysfs_remove_file_from_group(struct kobject *kobj,
const struct attribute *attr, const char *group)
{
struct kernfs_node *parent;
if (group) {
parent = kernfs_find_and_get(kobj->sd, group);
} else {
parent = kobj->sd;
kernfs_get(parent);
}
if (parent) {
kernfs_remove_by_name(parent, attr->name);
kernfs_put(parent);
}
}
EXPORT_SYMBOL_GPL(sysfs_remove_file_from_group);
/**
* sysfs_create_bin_file - create binary file for object.
* @kobj: object.
* @attr: attribute descriptor.
*/
int sysfs_create_bin_file(struct kobject *kobj,
const struct bin_attribute *attr)
{
kuid_t uid;
kgid_t gid;
if (WARN_ON(!kobj || !kobj->sd || !attr))
return -EINVAL;
kobject_get_ownership(kobj, &uid, &gid);
return sysfs_add_bin_file_mode_ns(kobj->sd, attr, attr->attr.mode, uid,
gid, NULL);
}
EXPORT_SYMBOL_GPL(sysfs_create_bin_file);
/**
* sysfs_remove_bin_file - remove binary file for object.
* @kobj: object.
* @attr: attribute descriptor.
*/
void sysfs_remove_bin_file(struct kobject *kobj,
const struct bin_attribute *attr)
{
kernfs_remove_by_name(kobj->sd, attr->attr.name);
}
EXPORT_SYMBOL_GPL(sysfs_remove_bin_file);
static int internal_change_owner(struct kernfs_node *kn, kuid_t kuid,
kgid_t kgid)
{
struct iattr newattrs = {
.ia_valid = ATTR_UID | ATTR_GID,
.ia_uid = kuid,
.ia_gid = kgid,
};
return kernfs_setattr(kn, &newattrs);
}
/**
* sysfs_link_change_owner - change owner of a sysfs file.
* @kobj: object of the kernfs_node the symlink is located in.
* @targ: object of the kernfs_node the symlink points to.
* @name: name of the link.
* @kuid: new owner's kuid
* @kgid: new owner's kgid
*
* This function looks up the sysfs symlink entry @name under @kobj and changes
* the ownership to @kuid/@kgid. The symlink is looked up in the namespace of
* @targ.
*
* Returns 0 on success or error code on failure.
*/
int sysfs_link_change_owner(struct kobject *kobj, struct kobject *targ,
const char *name, kuid_t kuid, kgid_t kgid)
{
struct kernfs_node *kn = NULL;
int error;
if (!name || !kobj->state_in_sysfs || !targ->state_in_sysfs)
return -EINVAL;
error = -ENOENT;
kn = kernfs_find_and_get_ns(kobj->sd, name, targ->sd->ns);
if (!kn)
goto out;
error = -EINVAL;
if (kernfs_type(kn) != KERNFS_LINK)
goto out;
if (kn->symlink.target_kn->priv != targ)
goto out;
error = internal_change_owner(kn, kuid, kgid);
out:
kernfs_put(kn);
return error;
}
/**
* sysfs_file_change_owner - change owner of a sysfs file.
* @kobj: object.
* @name: name of the file to change.
* @kuid: new owner's kuid
* @kgid: new owner's kgid
*
* This function looks up the sysfs entry @name under @kobj and changes the
* ownership to @kuid/@kgid.
*
* Returns 0 on success or error code on failure.
*/
int sysfs_file_change_owner(struct kobject *kobj, const char *name, kuid_t kuid,
kgid_t kgid)
{
struct kernfs_node *kn;
int error;
if (!name)
return -EINVAL;
if (!kobj->state_in_sysfs)
return -EINVAL;
kn = kernfs_find_and_get(kobj->sd, name);
if (!kn)
return -ENOENT;
error = internal_change_owner(kn, kuid, kgid);
kernfs_put(kn);
return error;
}
EXPORT_SYMBOL_GPL(sysfs_file_change_owner);
/**
* sysfs_change_owner - change owner of the given object.
* @kobj: object.
* @kuid: new owner's kuid
* @kgid: new owner's kgid
*
* Change the owner of the default directory, files, groups, and attributes of
* @kobj to @kuid/@kgid. Note that sysfs_change_owner mirrors how the sysfs
* entries for a kobject are added by driver core. In summary,
* sysfs_change_owner() takes care of the default directory entry for @kobj,
* the default attributes associated with the ktype of @kobj and the default
* attributes associated with the ktype of @kobj.
* Additional properties not added by driver core have to be changed by the
* driver or subsystem which created them. This is similar to how
* driver/subsystem specific entries are removed.
*
* Returns 0 on success or error code on failure.
*/
int sysfs_change_owner(struct kobject *kobj, kuid_t kuid, kgid_t kgid)
{
int error;
const struct kobj_type *ktype;
if (!kobj->state_in_sysfs)
return -EINVAL;
/* Change the owner of the kobject itself. */
error = internal_change_owner(kobj->sd, kuid, kgid);
if (error)
return error;
ktype = get_ktype(kobj);
if (ktype) {
/*
* Change owner of the default groups associated with the
* ktype of @kobj.
*/
error = sysfs_groups_change_owner(kobj, ktype->default_groups,
kuid, kgid);
if (error)
return error;
}
return 0;
}
EXPORT_SYMBOL_GPL(sysfs_change_owner);
/**
* sysfs_emit - scnprintf equivalent, aware of PAGE_SIZE buffer.
* @buf: start of PAGE_SIZE buffer.
* @fmt: format
* @...: optional arguments to @format
*
*
* Returns number of characters written to @buf.
*/
int sysfs_emit(char *buf, const char *fmt, ...)
{
va_list args;
int len;
if (WARN(!buf || offset_in_page(buf),
"invalid sysfs_emit: buf:%p\n", buf))
return 0;
va_start(args, fmt);
len = vscnprintf(buf, PAGE_SIZE, fmt, args);
va_end(args);
return len;
}
EXPORT_SYMBOL_GPL(sysfs_emit);
/**
* sysfs_emit_at - scnprintf equivalent, aware of PAGE_SIZE buffer.
* @buf: start of PAGE_SIZE buffer.
* @at: offset in @buf to start write in bytes
* @at must be >= 0 && < PAGE_SIZE
* @fmt: format
* @...: optional arguments to @fmt
*
*
* Returns number of characters written starting at &@buf[@at].
*/
int sysfs_emit_at(char *buf, int at, const char *fmt, ...)
{
va_list args;
int len;
if (WARN(!buf || offset_in_page(buf) || at < 0 || at >= PAGE_SIZE,
"invalid sysfs_emit_at: buf:%p at:%d\n", buf, at))
return 0;
va_start(args, fmt);
len = vscnprintf(buf + at, PAGE_SIZE - at, fmt, args);
va_end(args);
return len;
}
EXPORT_SYMBOL_GPL(sysfs_emit_at);
/**
* sysfs_bin_attr_simple_read - read callback to simply copy from memory.
* @file: attribute file which is being read.
* @kobj: object to which the attribute belongs.
* @attr: attribute descriptor.
* @buf: destination buffer.
* @off: offset in bytes from which to read.
* @count: maximum number of bytes to read.
*
* Simple ->read() callback for bin_attributes backed by a buffer in memory.
* The @private and @size members in struct bin_attribute must be set to the
* buffer's location and size before the bin_attribute is created in sysfs.
*
* Bounds check for @off and @count is done in sysfs_kf_bin_read().
* Negative value check for @off is done in vfs_setpos() and default_llseek().
*
* Returns number of bytes written to @buf.
*/
ssize_t sysfs_bin_attr_simple_read(struct file *file, struct kobject *kobj,
struct bin_attribute *attr, char *buf,
loff_t off, size_t count)
{
memcpy(buf, attr->private + off, count);
return count;
}
EXPORT_SYMBOL_GPL(sysfs_bin_attr_simple_read);