// SPDX-License-Identifier: GPL-2.0
/*
 * module.c - module sysfs fun for drivers
 */
#include <linux/device.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/string.h>
#include "base.h"

static char *make_driver_name(const struct device_driver *drv)
{
        char *driver_name;

        driver_name = kasprintf(GFP_KERNEL, "%s:%s", drv->bus->name, drv->name);
        if (!driver_name)
                return NULL;

        return driver_name;
}

static void module_create_drivers_dir(struct module_kobject *mk)
{
        static DEFINE_MUTEX(drivers_dir_mutex);

        mutex_lock(&drivers_dir_mutex);
        if (mk && !mk->drivers_dir)
                mk->drivers_dir = kobject_create_and_add("drivers", &mk->kobj);
        mutex_unlock(&drivers_dir_mutex);
}

int module_add_driver(struct module *mod, const struct device_driver *drv)
{
        char *driver_name;
        struct module_kobject *mk = NULL;
        int ret;

        if (!drv)
                return 0;

        if (mod)
                mk = &mod->mkobj;
        else if (drv->mod_name) {
                /* Lookup or create built-in module entry in /sys/modules */
                mk = lookup_or_create_module_kobject(drv->mod_name);
                if (mk) {
                        /* remember our module structure */
                        drv->p->mkobj = mk;
                        /* lookup_or_create_module_kobject took a reference */
                        kobject_put(&mk->kobj);
                }
        }

        if (!mk)
                return 0;

        ret = sysfs_create_link(&drv->p->kobj, &mk->kobj, "module");
        if (ret)
                return ret;

        driver_name = make_driver_name(drv);
        if (!driver_name) {
                ret = -ENOMEM;
                goto out_remove_kobj;
        }

        module_create_drivers_dir(mk);
        if (!mk->drivers_dir) {
                ret = -EINVAL;
                goto out_free_driver_name;
        }

        ret = sysfs_create_link(mk->drivers_dir, &drv->p->kobj, driver_name);
        if (ret)
                goto out_remove_drivers_dir;

        kfree(driver_name);

        return 0;

out_remove_drivers_dir:
        sysfs_remove_link(mk->drivers_dir, driver_name);

out_free_driver_name:
        kfree(driver_name);

out_remove_kobj:
        sysfs_remove_link(&drv->p->kobj, "module");
        return ret;
}

void module_remove_driver(const struct device_driver *drv)
{
        struct module_kobject *mk = NULL;
        char *driver_name;

        if (!drv)
                return;

        sysfs_remove_link(&drv->p->kobj, "module");

        if (drv->owner)
                mk = &drv->owner->mkobj;
        else if (drv->p->mkobj)
                mk = drv->p->mkobj;
        if (mk && mk->drivers_dir) {
                driver_name = make_driver_name(drv);
                if (driver_name) {
                        sysfs_remove_link(mk->drivers_dir, driver_name);
                        kfree(driver_name);
                }
        }
}