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-rw-r--r--fs/sysfs/file.c414
1 files changed, 337 insertions, 77 deletions
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index 51398457fe00..3825e780cc58 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -6,7 +6,7 @@
* Copyright (c) 2007 SUSE Linux Products GmbH
* Copyright (c) 2007 Tejun Heo <teheo@suse.de>
*
- * Please see Documentation/filesystems/sysfs.txt for more information.
+ * Please see Documentation/filesystems/sysfs.rst for more information.
*/
#include <linux/module.h>
@@ -15,9 +15,15 @@
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/seq_file.h>
+#include <linux/mm.h>
#include "sysfs.h"
-#include "../kernfs/kernfs-internal.h"
+
+static struct kobject *sysfs_file_kobj(struct kernfs_node *kn)
+{
+ guard(rcu)();
+ return rcu_dereference(kn->__parent)->priv;
+}
/*
* Determine ktype->sysfs_ops for the given kernfs_node. This function
@@ -25,7 +31,7 @@
*/
static const struct sysfs_ops *sysfs_file_ops(struct kernfs_node *kn)
{
- struct kobject *kobj = kn->parent->priv;
+ struct kobject *kobj = sysfs_file_kobj(kn);
if (kn->flags & KERNFS_LOCKDEP)
lockdep_assert_held(kn);
@@ -40,11 +46,14 @@ static const struct sysfs_ops *sysfs_file_ops(struct kernfs_node *kn)
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;
+ struct kobject *kobj = sysfs_file_kobj(of->kn);
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) {
@@ -53,15 +62,9 @@ static int sysfs_kf_seq_show(struct seq_file *sf, void *v)
}
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;
- }
+ 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
@@ -80,8 +83,8 @@ static int sysfs_kf_seq_show(struct seq_file *sf, void *v)
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;
+ const struct bin_attribute *battr = of->kn->priv;
+ struct kobject *kobj = sysfs_file_kobj(of->kn);
loff_t size = file_inode(of->file)->i_size;
if (!count)
@@ -105,7 +108,7 @@ 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;
+ struct kobject *kobj = sysfs_file_kobj(of->kn);
ssize_t len;
/*
@@ -131,7 +134,7 @@ 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;
+ struct kobject *kobj = sysfs_file_kobj(of->kn);
if (!count)
return 0;
@@ -143,8 +146,8 @@ static ssize_t sysfs_kf_write(struct kernfs_open_file *of, char *buf,
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;
+ const struct bin_attribute *battr = of->kn->priv;
+ struct kobject *kobj = sysfs_file_kobj(of->kn);
loff_t size = file_inode(of->file)->i_size;
if (size) {
@@ -164,12 +167,34 @@ static ssize_t sysfs_kf_bin_write(struct kernfs_open_file *of, char *buf,
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;
+ const struct bin_attribute *battr = of->kn->priv;
+ struct kobject *kobj = sysfs_file_kobj(of->kn);
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)
+{
+ const struct bin_attribute *battr = of->kn->priv;
+ struct kobject *kobj = sysfs_file_kobj(of->kn);
+
+ 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)
+{
+ const 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;
@@ -241,62 +266,79 @@ 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, bool is_bin,
- umode_t mode, kuid_t uid, kgid_t gid, const void *ns)
+ 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;
+ const struct kernfs_ops *ops = NULL;
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;
+
+ /* 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 {
- 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;
+ 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, size_t size,
+ 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)
@@ -329,9 +371,7 @@ int sysfs_create_file_ns(struct kobject *kobj, const struct attribute *attr,
return -EINVAL;
kobject_get_ownership(kobj, &uid, &gid);
- return sysfs_add_file_mode_ns(kobj->sd, attr, false, attr->mode,
- uid, gid, ns);
-
+ return sysfs_add_file_mode_ns(kobj->sd, attr, attr->mode, uid, gid, ns);
}
EXPORT_SYMBOL_GPL(sysfs_create_file_ns);
@@ -374,8 +414,8 @@ int sysfs_add_file_to_group(struct kobject *kobj,
return -ENOENT;
kobject_get_ownership(kobj, &uid, &gid);
- error = sysfs_add_file_mode_ns(parent, attr, false,
- attr->mode, uid, gid, NULL);
+ error = sysfs_add_file_mode_ns(parent, attr, attr->mode, uid, gid,
+ NULL);
kernfs_put(parent);
return error;
@@ -429,6 +469,8 @@ struct kernfs_node *sysfs_break_active_protection(struct kobject *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);
@@ -446,7 +488,7 @@ EXPORT_SYMBOL_GPL(sysfs_break_active_protection);
*/
void sysfs_unbreak_active_protection(struct kernfs_node *kn)
{
- struct kobject *kobj = kn->parent->priv;
+ struct kobject *kobj = sysfs_file_kobj(kn);
kernfs_unbreak_active_protection(kn);
kernfs_put(kn);
@@ -493,10 +535,12 @@ bool sysfs_remove_file_self(struct kobject *kobj, const struct attribute *attr)
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]);
}
@@ -542,8 +586,8 @@ int sysfs_create_bin_file(struct kobject *kobj,
return -EINVAL;
kobject_get_ownership(kobj, &uid, &gid);
- return sysfs_add_file_mode_ns(kobj->sd, &attr->attr, true,
- attr->attr.mode, uid, gid, NULL);
+ return sysfs_add_bin_file_mode_ns(kobj->sd, attr, attr->attr.mode,
+ attr->size, uid, gid, NULL);
}
EXPORT_SYMBOL_GPL(sysfs_create_bin_file);
@@ -558,3 +602,219 @@ void sysfs_remove_bin_file(struct kobject *kobj,
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,
+ const 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);
generated by cgit (git 2.34.1) at 2025-12-22 09:10:38 +0000