// SPDX-License-Identifier: GPL-2.0
#include <linux/of.h>
#include <linux/slab.h>

#include "of_private.h"

/* true when node is initialized */
static int of_node_is_initialized(const struct device_node *node)
{
        return node && node->kobj.state_initialized;
}

/* true when node is attached (i.e. present on sysfs) */
int of_node_is_attached(const struct device_node *node)
{
        return node && node->kobj.state_in_sysfs;
}


#ifndef CONFIG_OF_DYNAMIC
static void of_node_release(struct kobject *kobj)
{
        /* Without CONFIG_OF_DYNAMIC, no nodes gets freed */
}
#endif /* CONFIG_OF_DYNAMIC */

const struct kobj_type of_node_ktype = {
        .release = of_node_release,
};

static ssize_t of_node_property_read(struct file *filp, struct kobject *kobj,
                                const struct bin_attribute *bin_attr, char *buf,
                                loff_t offset, size_t count)
{
        struct property *pp = container_of(bin_attr, struct property, attr);
        return memory_read_from_buffer(buf, count, &offset, pp->value, pp->length);
}

/* always return newly allocated name, caller must free after use */
static const char *safe_name(const struct kobject *kobj, const char *orig_name)
{
        const char *name = orig_name;
        struct kernfs_node *kn;
        int i = 0;

        /* don't be a hero. After 16 tries give up */
        while (i < 16 && (kn = sysfs_get_dirent(kobj->sd, name))) {
                sysfs_put(kn);
                if (name != orig_name)
                        kfree(name);
                name = kasprintf(GFP_KERNEL, "%s#%i", orig_name, ++i);
        }

        if (name == orig_name) {
                name = kstrdup(orig_name, GFP_KERNEL);
        } else {
                pr_warn("Duplicate name in %s, renamed to \"%s\"\n",
                        kobject_name(kobj), name);
        }
        return name;
}

int __of_add_property_sysfs(struct device_node *np, struct property *pp)
{
        int rc;

        /* Important: Don't leak passwords */
        bool secure = strncmp(pp->name, "security-", 9) == 0;

        if (!IS_ENABLED(CONFIG_SYSFS))
                return 0;

        if (!of_kset || !of_node_is_attached(np))
                return 0;

        sysfs_bin_attr_init(&pp->attr);
        pp->attr.attr.name = safe_name(&np->kobj, pp->name);
        pp->attr.attr.mode = secure ? 0400 : 0444;
        pp->attr.size = secure ? 0 : pp->length;
        pp->attr.read = of_node_property_read;

        rc = sysfs_create_bin_file(&np->kobj, &pp->attr);
        WARN(rc, "error adding attribute %s to node %pOF\n", pp->name, np);
        return rc;
}

void __of_sysfs_remove_bin_file(struct device_node *np, const struct property *prop)
{
        if (!IS_ENABLED(CONFIG_SYSFS))
                return;

        sysfs_remove_bin_file(&np->kobj, &prop->attr);
        kfree(prop->attr.attr.name);
}

void __of_remove_property_sysfs(struct device_node *np, const struct property *prop)
{
        /* at early boot, bail here and defer setup to of_init() */
        if (of_kset && of_node_is_attached(np))
                __of_sysfs_remove_bin_file(np, prop);
}

void __of_update_property_sysfs(struct device_node *np, struct property *newprop,
                const struct property *oldprop)
{
        /* At early boot, bail out and defer setup to of_init() */
        if (!of_kset)
                return;

        if (oldprop)
                __of_sysfs_remove_bin_file(np, oldprop);
        __of_add_property_sysfs(np, newprop);
}

int __of_attach_node_sysfs(struct device_node *np)
{
        const char *name;
        struct kobject *parent;
        struct property *pp;
        int rc;

        if (!IS_ENABLED(CONFIG_SYSFS) || !of_kset)
                return 0;

        np->kobj.kset = of_kset;
        if (!np->parent) {
                /* Nodes without parents are new top level trees */
                name = safe_name(&of_kset->kobj, "base");
                parent = NULL;
        } else {
                name = safe_name(&np->parent->kobj, kbasename(np->full_name));
                parent = &np->parent->kobj;
        }
        if (!name)
                return -ENOMEM;

        rc = kobject_add(&np->kobj, parent, "%s", name);
        kfree(name);
        if (rc)
                return rc;

        for_each_property_of_node(np, pp)
                __of_add_property_sysfs(np, pp);

        of_node_get(np);
        return 0;
}

void __of_detach_node_sysfs(struct device_node *np)
{
        struct property *pp;

        BUG_ON(!of_node_is_initialized(np));
        if (!of_kset)
                return;

        /* only remove properties if on sysfs */
        if (of_node_is_attached(np)) {
                for_each_property_of_node(np, pp)
                        __of_sysfs_remove_bin_file(np, pp);
                kobject_del(&np->kobj);
        }

        of_node_put(np);
}