155 lines
3.8 KiB
C
155 lines
3.8 KiB
C
/*
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* fs/sysfs/group.c - Operations for adding/removing multiple files at once.
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*
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* Copyright (c) 2003 Patrick Mochel
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* Copyright (c) 2003 Open Source Development Lab
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*
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* This file is released undert the GPL v2.
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*
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*/
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#include <linux/kobject.h>
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#include <linux/module.h>
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#include <linux/dcache.h>
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#include <linux/namei.h>
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#include <linux/err.h>
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#include "sysfs.h"
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static void remove_files(struct sysfs_dirent *dir_sd, struct kobject *kobj,
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const struct attribute_group *grp)
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{
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struct attribute *const* attr;
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int i;
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for (i = 0, attr = grp->attrs; *attr; i++, attr++)
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sysfs_hash_and_remove(dir_sd, (*attr)->name);
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}
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static int create_files(struct sysfs_dirent *dir_sd, struct kobject *kobj,
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const struct attribute_group *grp, int update)
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{
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struct attribute *const* attr;
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int error = 0, i;
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for (i = 0, attr = grp->attrs; *attr && !error; i++, attr++) {
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mode_t mode = 0;
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/* in update mode, we're changing the permissions or
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* visibility. Do this by first removing then
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* re-adding (if required) the file */
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if (update)
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sysfs_hash_and_remove(dir_sd, (*attr)->name);
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if (grp->is_visible) {
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mode = grp->is_visible(kobj, *attr, i);
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if (!mode)
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continue;
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}
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error = sysfs_add_file_mode(dir_sd, *attr, SYSFS_KOBJ_ATTR,
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(*attr)->mode | mode);
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if (unlikely(error))
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break;
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}
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if (error)
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remove_files(dir_sd, kobj, grp);
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return error;
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}
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static int internal_create_group(struct kobject *kobj, int update,
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const struct attribute_group *grp)
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{
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struct sysfs_dirent *sd;
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int error;
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BUG_ON(!kobj || (!update && !kobj->sd));
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/* Updates may happen before the object has been instantiated */
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if (unlikely(update && !kobj->sd))
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return -EINVAL;
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if (grp->name) {
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error = sysfs_create_subdir(kobj, grp->name, &sd);
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if (error)
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return error;
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} else
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sd = kobj->sd;
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sysfs_get(sd);
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error = create_files(sd, kobj, grp, update);
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if (error) {
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if (grp->name)
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sysfs_remove_subdir(sd);
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}
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sysfs_put(sd);
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return error;
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}
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/**
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* sysfs_create_group - given a directory kobject, create an attribute group
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* @kobj: The kobject to create the group on
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* @grp: The attribute group to create
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*
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* This function creates a group for the first time. It will explicitly
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* warn and error if any of the attribute files being created already exist.
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*
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* Returns 0 on success or error.
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*/
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int sysfs_create_group(struct kobject *kobj,
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const struct attribute_group *grp)
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{
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return internal_create_group(kobj, 0, grp);
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}
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/**
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* sysfs_update_group - given a directory kobject, create an attribute group
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* @kobj: The kobject to create the group on
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* @grp: The attribute group to create
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*
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* This function updates an attribute group. Unlike
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* sysfs_create_group(), it will explicitly not warn or error if any
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* of the attribute files being created already exist. Furthermore,
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* if the visibility of the files has changed through the is_visible()
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* callback, it will update the permissions and add or remove the
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* relevant files.
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*
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* The primary use for this function is to call it after making a change
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* that affects group visibility.
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*
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* Returns 0 on success or error.
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*/
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int sysfs_update_group(struct kobject *kobj,
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const struct attribute_group *grp)
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{
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return internal_create_group(kobj, 1, grp);
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}
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void sysfs_remove_group(struct kobject * kobj,
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const struct attribute_group * grp)
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{
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struct sysfs_dirent *dir_sd = kobj->sd;
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struct sysfs_dirent *sd;
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if (grp->name) {
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sd = sysfs_get_dirent(dir_sd, grp->name);
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if (!sd) {
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WARN(!sd, KERN_WARNING "sysfs group %p not found for "
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"kobject '%s'\n", grp, kobject_name(kobj));
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return;
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}
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} else
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sd = sysfs_get(dir_sd);
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remove_files(sd, kobj, grp);
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if (grp->name)
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sysfs_remove_subdir(sd);
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sysfs_put(sd);
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}
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EXPORT_SYMBOL_GPL(sysfs_create_group);
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EXPORT_SYMBOL_GPL(sysfs_update_group);
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EXPORT_SYMBOL_GPL(sysfs_remove_group);
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