Release 4.11 fs/sysfs/file.c

/*
 * 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/list.h>
#include <linux/mutex.h>
#include <linux/seq_file.h>

#include "sysfs.h"
#include "../kernfs/kernfs-internal.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;
}

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/*
 * 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;

	/* 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);

	/*
         * Invoke show().  Control may reach here via seq file lseek even
         * if @ops->show() isn't implemented.
         */
	if (ops->show) {
		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) {
		print_symbol("fill_read_buffer: %s returned bad count\n",
			(unsigned long)ops->show);
		/* Try to struggle along */
		count = PAGE_SIZE - 1;
	}
	seq_commit(sf, count);
	return 0;
}

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87
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44
25.43%
1
5.88%
Andrew Morton
30
17.34%
3
17.65%
Neil Brown
5
2.89%
1
5.88%
Rusty Russell
4
2.31%
1
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Miao Xie
2
1.16%
1
5.88%
Emese Revfy
1
0.58%
1
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17
100.00%



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);
}

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124
99.20%
4
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1
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/* 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);
}

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/* 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);
}

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/* 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);
}

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Tejun Heo
118
94.40%
9
81.82%
Patrick Mochel
5
4.00%
1
9.09%
Vladimir Zapolskiy
2
1.60%
1
9.09%
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11
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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);
}

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53.57%
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100.00%



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);
	}
}
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Tejun Heo
40
42.11%
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Trent Piepho
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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,
};



int sysfs_add_file_mode_ns(struct kernfs_node *parent,
			   const struct attribute *attr, bool is_bin,
			   umode_t mode, const void *ns)
{
	struct lock_class_key *key = NULL;
	const struct kernfs_ops *ops;
	struct kernfs_node *kn;
	loff_t size;

	if (!is_bin) {
		struct kobject *kobj = parent->priv;
		const struct sysfs_ops *sysfs_ops = kobj->ktype->sysfs_ops;

		/* 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 (sysfs_ops->show && sysfs_ops->store) {
			if (mode & SYSFS_PREALLOC)
				ops = &sysfs_prealloc_kfops_rw;
			else
				ops = &sysfs_file_kfops_rw;
		} else if (sysfs_ops->show) {
			if (mode & SYSFS_PREALLOC)
				ops = &sysfs_prealloc_kfops_ro;
			else
				ops = &sysfs_file_kfops_ro;
		} else if (sysfs_ops->store) {
			if (mode & SYSFS_PREALLOC)
				ops = &sysfs_prealloc_kfops_wo;
			else
				ops = &sysfs_file_kfops_wo;
		} else
			ops = &sysfs_file_kfops_empty;

		size = PAGE_SIZE;
	} else {
		struct bin_attribute *battr = (void *)attr;

		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;

		size = battr->size;
	}

#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, 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;
}

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301
83.61%
11
61.11%
Neil Brown
44
12.22%
2
11.11%
Patrick Mochel
9
2.50%
2
11.11%
Andrew Morton
4
1.11%
1
5.56%
Al Viro
1
0.28%
1
5.56%
James Bottomley
1
0.28%
1
5.56%
Total
360
100.00%
18
100.00%



int sysfs_add_file(struct kernfs_node *parent, const struct attribute *attr,
		   bool is_bin)
{
	return sysfs_add_file_mode_ns(parent, attr, is_bin, attr->mode, NULL);
}

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/**
 * 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)
{
	BUG_ON(!kobj || !kobj->sd || !attr);

	return sysfs_add_file_mode_ns(kobj->sd, attr, false, attr->mode, ns);

}
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25
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Tejun Heo
16
30.19%
3
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Andrew Morton
12
22.64%
1
16.67%
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53
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6
100.00%


EXPORT_SYMBOL_GPL(sysfs_create_file_ns);



int sysfs_create_files(struct kobject *kobj, const struct attribute **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;
}
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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;
	int error;

	if (group) {
		parent = kernfs_find_and_get(kobj->sd, group);
	} else {
		parent = kobj->sd;
		kernfs_get(parent);
	}

	if (!parent)
		return -ENOENT;

	error = sysfs_add_file(parent, attr, false);
	kernfs_put(parent);

	return error;
}
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Tejun Heo
24
27.27%
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66.67%
James Bottomley
11
12.50%
1
16.67%
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100.00%


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;
}
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43
44.79%
1
9.09%
Maneesh Soni
28
29.17%
1
9.09%
Tejun Heo
21
21.88%
5
45.45%
Al Viro
1
1.04%
1
9.09%
Jean Delvare
1
1.04%
1
9.09%
Miklos Szeredi
1
1.04%
1
9.09%
Christoph Hellwig
1
1.04%
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9.09%
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EXPORT_SYMBOL_GPL(sysfs_chmod_file);

/**
 * 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);
}
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21
51.22%
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Tejun Heo
16
39.02%
5
62.50%
Eric W. Biedermann
4
9.76%
1
12.50%
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8
100.00%


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;
}

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void sysfs_remove_files(struct kobject *kobj, const struct attribute **ptr)
{
	int i;
	for (i = 0; ptr[i]; i++)
		sysfs_remove_file(kobj, ptr[i]);
}
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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);
	}
}
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47
61.04%
1
16.67%
Tejun Heo
19
24.68%
4
66.67%
James Bottomley
11
14.29%
1
16.67%
Total
77
100.00%
6
100.00%


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)
{
	BUG_ON(!kobj || !kobj->sd || !attr);

	return sysfs_add_file(kobj->sd, &attr->attr, true);
}
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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);
}
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EXPORT_SYMBOL_GPL(sysfs_remove_bin_file);
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Tejun Heo
1221
57.76%
37
49.33%
Neil Brown
294
13.91%
7
9.33%
Andi Kleen
122
5.77%
1
1.33%
Alan Stern
112
5.30%
1
1.33%
Patrick Mochel
112
5.30%
3
4.00%
Andrew Morton
49
2.32%
4
5.33%
James Bottomley
49
2.32%
2
2.67%
Kay Sievers
49
2.32%
1
1.33%
Konstantin Khlebnikov
30
1.42%
1
1.33%
Maneesh Soni
28
1.32%
1
1.33%
Greg Kroah-Hartman
18
0.85%
1
1.33%
Rusty Russell
4
0.19%
1
1.33%
Eric W. Biedermann
4
0.19%
1
1.33%
Robert P. J. Day
3
0.14%
1
1.33%
Vladimir Zapolskiy
3
0.14%
2
2.67%
Oliver Neukum
3
0.14%
1
1.33%
Al Viro
2
0.09%
2
2.67%
Linus Torvalds
2
0.09%
1
1.33%
Miao Xie
2
0.09%
1
1.33%
Trent Piepho
2
0.09%
1
1.33%
Christoph Hellwig
1
0.05%
1
1.33%
Emese Revfy
1
0.05%
1
1.33%
Jean Delvare
1
0.05%
1
1.33%
Dave Young
1
0.05%
1
1.33%
Miklos Szeredi
1
0.05%
1
1.33%
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75
100.00%
Directory: fs/sysfs

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