group.c

Go to the documentation of this file.

/*
 * fs/sysfs/group.c - Operations for adding/removing multiple files at once.
 *
 * Copyright (c) 2003 Patrick Mochel
 * Copyright (c) 2003 Open Source Development Lab
 *
 * This file is released undert the GPL v2. 
 *
 */

#include <linux/kobject.h>
#include <linux/module.h>
#include <linux/dcache.h>
#include <linux/namei.h>
#include <linux/err.h>
#include "sysfs.h"


static void remove_files(struct sysfs_dirent *dir_sd, struct kobject *kobj,
             const struct attribute_group *grp)
{
    struct attribute *const* attr;
    int i;

    for (i = 0, attr = grp->attrs; *attr; i++, attr++)
        sysfs_hash_and_remove(dir_sd, NULL, (*attr)->name);
}

static int create_files(struct sysfs_dirent *dir_sd, struct kobject *kobj,
            const struct attribute_group *grp, int update)
{
    struct attribute *const* attr;
    int error = 0, i;

    for (i = 0, attr = grp->attrs; *attr && !error; i++, attr++) {
        umode_t mode = 0;

        /* in update mode, we're changing the permissions or
         * visibility.  Do this by first removing then
         * re-adding (if required) the file */
        if (update)
            sysfs_hash_and_remove(dir_sd, NULL, (*attr)->name);
        if (grp->is_visible) {
            mode = grp->is_visible(kobj, *attr, i);
            if (!mode)
                continue;
        }
        error = sysfs_add_file_mode(dir_sd, *attr, SYSFS_KOBJ_ATTR,
                        (*attr)->mode | mode);
        if (unlikely(error))
            break;
    }
    if (error)
        remove_files(dir_sd, kobj, grp);
    return error;
}


static int internal_create_group(struct kobject *kobj, int update,
                 const struct attribute_group *grp)
{
    struct sysfs_dirent *sd;
    int error;

    BUG_ON(!kobj || (!update && !kobj->sd));

    /* Updates may happen before the object has been instantiated */
    if (unlikely(update && !kobj->sd))
        return -EINVAL;
    if (!grp->attrs) {
        WARN(1, "sysfs: attrs not set by subsystem for group: %s/%s\n",
            kobj->name, grp->name ? "" : grp->name);
        return -EINVAL;
    }
    if (grp->name) {
        error = sysfs_create_subdir(kobj, grp->name, &sd);
        if (error)
            return error;
    } else
        sd = kobj->sd;
    sysfs_get(sd);
    error = create_files(sd, kobj, grp, update);
    if (error) {
        if (grp->name)
            sysfs_remove_subdir(sd);
    }
    sysfs_put(sd);
    return error;
}

int sysfs_create_group(struct kobject *kobj,
               const struct attribute_group *grp)
{
    return internal_create_group(kobj, 0, grp);
}

int sysfs_update_group(struct kobject *kobj,
               const struct attribute_group *grp)
{
    return internal_create_group(kobj, 1, grp);
}



void sysfs_remove_group(struct kobject * kobj, 
            const struct attribute_group * grp)
{
    struct sysfs_dirent *dir_sd = kobj->sd;
    struct sysfs_dirent *sd;

    if (grp->name) {
        sd = sysfs_get_dirent(dir_sd, NULL, grp->name);
        if (!sd) {
            WARN(!sd, KERN_WARNING "sysfs group %p not found for "
                "kobject '%s'\n", grp, kobject_name(kobj));
            return;
        }
    } else
        sd = sysfs_get(dir_sd);

    remove_files(sd, kobj, grp);
    if (grp->name)
        sysfs_remove_subdir(sd);

    sysfs_put(sd);
}

int sysfs_merge_group(struct kobject *kobj,
               const struct attribute_group *grp)
{
    struct sysfs_dirent *dir_sd;
    int error = 0;
    struct attribute *const *attr;
    int i;

    dir_sd = sysfs_get_dirent(kobj->sd, NULL, grp->name);
    if (!dir_sd)
        return -ENOENT;

    for ((i = 0, attr = grp->attrs); *attr && !error; (++i, ++attr))
        error = sysfs_add_file(dir_sd, *attr, SYSFS_KOBJ_ATTR);
    if (error) {
        while (--i >= 0)
            sysfs_hash_and_remove(dir_sd, NULL, (*--attr)->name);
    }
    sysfs_put(dir_sd);

    return error;
}
EXPORT_SYMBOL_GPL(sysfs_merge_group);

void sysfs_unmerge_group(struct kobject *kobj,
               const struct attribute_group *grp)
{
    struct sysfs_dirent *dir_sd;
    struct attribute *const *attr;

    dir_sd = sysfs_get_dirent(kobj->sd, NULL, grp->name);
    if (dir_sd) {
        for (attr = grp->attrs; *attr; ++attr)
            sysfs_hash_and_remove(dir_sd, NULL, (*attr)->name);
        sysfs_put(dir_sd);
    }
}
EXPORT_SYMBOL_GPL(sysfs_unmerge_group);


EXPORT_SYMBOL_GPL(sysfs_create_group);
EXPORT_SYMBOL_GPL(sysfs_update_group);
EXPORT_SYMBOL_GPL(sysfs_remove_group);