// SPDX-License-Identifier: GPL-2.0-or-later/* * Module sysfs support * * Copyright (C) 2008 Rusty Russell */ #include <linux/module.h>#include <linux/kernel.h>#include <linux/fs.h>#include <linux/sysfs.h>#include <linux/slab.h>#include <linux/kallsyms.h>#include <linux/mutex.h>#include "internal.h" /* * /sys/module/foo/sections stuff * J. Corbet <corbet@lwn.net> */#ifdef CONFIG_KALLSYMSstruct module_sect_attr {	struct bin_attribute battr;	unsigned long address;}; struct module_sect_attrs {	struct attribute_group grp;	unsigned int nsections;	struct module_sect_attr attrs[];}; #define MODULE_SECT_READ_SIZE (3 /* "0x", "\n" */ + (BITS_PER_LONG / 4))static ssize_t module_sect_read(struct file *file, struct kobject *kobj,				struct bin_attribute *battr,				char *buf, loff_t pos, size_t count){	struct module_sect_attr *sattr =		container_of(battr, struct module_sect_attr, battr);	char bounce[MODULE_SECT_READ_SIZE + 1];	size_t wrote; 	if (pos != 0)		return -EINVAL; 	/*	 * Since we're a binary read handler, we must account for the	 * trailing NUL byte that sprintf will write: if "buf" is	 * too small to hold the NUL, or the NUL is exactly the last	 * byte, the read will look like it got truncated by one byte.	 * Since there is no way to ask sprintf nicely to not write	 * the NUL, we have to use a bounce buffer.	 */	wrote = scnprintf(bounce, sizeof(bounce), "0x%px\n",			  kallsyms_show_value(file->f_cred)				? (void *)sattr->address : NULL);	count = min(count, wrote);	memcpy(buf, bounce, count); 	return count;} static void free_sect_attrs(struct module_sect_attrs *sect_attrs){	unsigned int section; 	for (section = 0; section < sect_attrs->nsections; section++)		kfree(sect_attrs->attrs[section].battr.attr.name);	kfree(sect_attrs);} static int add_sect_attrs(struct module *mod, const struct load_info *info){	unsigned int nloaded = 0, i, size[2];	struct module_sect_attrs *sect_attrs;	struct module_sect_attr *sattr;	struct bin_attribute **gattr;	int ret; 	/* Count loaded sections and allocate structures */	for (i = 0; i < info->hdr->e_shnum; i++)		if (!sect_empty(&info->sechdrs[i]))			nloaded++;	size[0] = ALIGN(struct_size(sect_attrs, attrs, nloaded),			sizeof(sect_attrs->grp.bin_attrs[0]));	size[1] = (nloaded + 1) * sizeof(sect_attrs->grp.bin_attrs[0]);	sect_attrs = kzalloc(size[0] + size[1], GFP_KERNEL);	if (!sect_attrs)		return -ENOMEM; 	/* Setup section attributes. */	sect_attrs->grp.name = "sections";	sect_attrs->grp.bin_attrs = (void *)sect_attrs + size[0]; 	sect_attrs->nsections = 0;	sattr = &sect_attrs->attrs[0];	gattr = &sect_attrs->grp.bin_attrs[0];	for (i = 0; i < info->hdr->e_shnum; i++) {		Elf_Shdr *sec = &info->sechdrs[i]; 		if (sect_empty(sec))			continue;		sysfs_bin_attr_init(&sattr->battr);		sattr->address = sec->sh_addr;		sattr->battr.attr.name =			kstrdup(info->secstrings + sec->sh_name, GFP_KERNEL);		if (!sattr->battr.attr.name) {			ret = -ENOMEM;			goto out;		}		sect_attrs->nsections++;		sattr->battr.read = module_sect_read;		sattr->battr.size = MODULE_SECT_READ_SIZE;		sattr->battr.attr.mode = 0400;		*(gattr++) = &(sattr++)->battr;	}	*gattr = NULL; 	ret = sysfs_create_group(&mod->mkobj.kobj, &sect_attrs->grp);	if (ret)		goto out; 	mod->sect_attrs = sect_attrs;	return 0;out:	free_sect_attrs(sect_attrs);	return ret;} static void remove_sect_attrs(struct module *mod){	if (mod->sect_attrs) {		sysfs_remove_group(&mod->mkobj.kobj,				   &mod->sect_attrs->grp);		/*		 * We are positive that no one is using any sect attrs		 * at this point.  Deallocate immediately.		 */		free_sect_attrs(mod->sect_attrs);		mod->sect_attrs = NULL;	}} /* * /sys/module/foo/notes/.section.name gives contents of SHT_NOTE sections. */ struct module_notes_attrs {	struct kobject *dir;	unsigned int notes;	struct bin_attribute attrs[] __counted_by(notes);}; static void free_notes_attrs(struct module_notes_attrs *notes_attrs,			     unsigned int i){	if (notes_attrs->dir) {		while (i-- > 0)			sysfs_remove_bin_file(notes_attrs->dir,					      &notes_attrs->attrs[i]);		kobject_put(notes_attrs->dir);	}	kfree(notes_attrs);} static int add_notes_attrs(struct module *mod, const struct load_info *info){	unsigned int notes, loaded, i;	struct module_notes_attrs *notes_attrs;	struct bin_attribute *nattr;	int ret; 	/* Count notes sections and allocate structures.  */	notes = 0;	for (i = 0; i < info->hdr->e_shnum; i++)		if (!sect_empty(&info->sechdrs[i]) &&		    info->sechdrs[i].sh_type == SHT_NOTE)			++notes; 	if (notes == 0)		return 0; 	notes_attrs = kzalloc(struct_size(notes_attrs, attrs, notes),			      GFP_KERNEL);	if (!notes_attrs)		return -ENOMEM; 	notes_attrs->notes = notes;	nattr = &notes_attrs->attrs[0];	for (loaded = i = 0; i < info->hdr->e_shnum; ++i) {		if (sect_empty(&info->sechdrs[i]))			continue;		if (info->sechdrs[i].sh_type == SHT_NOTE) {			sysfs_bin_attr_init(nattr);			nattr->attr.name = mod->sect_attrs->attrs[loaded].battr.attr.name;			nattr->attr.mode = 0444;			nattr->size = info->sechdrs[i].sh_size;			nattr->private = (void *)info->sechdrs[i].sh_addr;			nattr->read = sysfs_bin_attr_simple_read;			++nattr;		}		++loaded;	} 	notes_attrs->dir = kobject_create_and_add("notes", &mod->mkobj.kobj);	if (!notes_attrs->dir) {		ret = -ENOMEM;		goto out;	} 	for (i = 0; i < notes; ++i) {		ret = sysfs_create_bin_file(notes_attrs->dir, &notes_attrs->attrs[i]);		if (ret)			goto out;	} 	mod->notes_attrs = notes_attrs;	return 0; out:	free_notes_attrs(notes_attrs, i);	return ret;} static void remove_notes_attrs(struct module *mod){	if (mod->notes_attrs)		free_notes_attrs(mod->notes_attrs, mod->notes_attrs->notes);} #else /* !CONFIG_KALLSYMS */static inline int add_sect_attrs(struct module *mod, const struct load_info *info){	return 0;}static inline void remove_sect_attrs(struct module *mod) { }static inline int add_notes_attrs(struct module *mod, const struct load_info *info){	return 0;}static inline void remove_notes_attrs(struct module *mod) { }#endif /* CONFIG_KALLSYMS */ static void del_usage_links(struct module *mod){#ifdef CONFIG_MODULE_UNLOAD	struct module_use *use; 	mutex_lock(&module_mutex);	list_for_each_entry(use, &mod->target_list, target_list)		sysfs_remove_link(use->target->holders_dir, mod->name);	mutex_unlock(&module_mutex);#endif} static int add_usage_links(struct module *mod){	int ret = 0;#ifdef CONFIG_MODULE_UNLOAD	struct module_use *use; 	mutex_lock(&module_mutex);	list_for_each_entry(use, &mod->target_list, target_list) {		ret = sysfs_create_link(use->target->holders_dir,					&mod->mkobj.kobj, mod->name);		if (ret)			break;	}	mutex_unlock(&module_mutex);	if (ret)		del_usage_links(mod);#endif	return ret;} static void module_remove_modinfo_attrs(struct module *mod, int end){	struct module_attribute *attr;	int i; 	for (i = 0; (attr = &mod->modinfo_attrs[i]); i++) {		if (end >= 0 && i > end)			break;		/* pick a field to test for end of list */		if (!attr->attr.name)			break;		sysfs_remove_file(&mod->mkobj.kobj, &attr->attr);		if (attr->free)			attr->free(mod);	}	kfree(mod->modinfo_attrs);} static int module_add_modinfo_attrs(struct module *mod){	struct module_attribute *attr;	struct module_attribute *temp_attr;	int error = 0;	int i; 	mod->modinfo_attrs = kzalloc((sizeof(struct module_attribute) *					(modinfo_attrs_count + 1)),					GFP_KERNEL);	if (!mod->modinfo_attrs)		return -ENOMEM; 	temp_attr = mod->modinfo_attrs;	for (i = 0; (attr = modinfo_attrs[i]); i++) {		if (!attr->test || attr->test(mod)) {			memcpy(temp_attr, attr, sizeof(*temp_attr));			sysfs_attr_init(&temp_attr->attr);			error = sysfs_create_file(&mod->mkobj.kobj,						  &temp_attr->attr);			if (error)				goto error_out;			++temp_attr;		}	} 	return 0; error_out:	if (i > 0)		module_remove_modinfo_attrs(mod, --i);	else		kfree(mod->modinfo_attrs);	return error;} static void mod_kobject_put(struct module *mod){	DECLARE_COMPLETION_ONSTACK(c); 	mod->mkobj.kobj_completion = &c;	kobject_put(&mod->mkobj.kobj);	wait_for_completion(&c);} static int mod_sysfs_init(struct module *mod){	int err;	struct kobject *kobj; 	if (!module_kset) {		pr_err("%s: module sysfs not initialized\n", mod->name);		err = -EINVAL;		goto out;	} 	kobj = kset_find_obj(module_kset, mod->name);	if (kobj) {		pr_err("%s: module is already loaded\n", mod->name);		kobject_put(kobj);		err = -EINVAL;		goto out;	} 	mod->mkobj.mod = mod; 	memset(&mod->mkobj.kobj, 0, sizeof(mod->mkobj.kobj));	mod->mkobj.kobj.kset = module_kset;	err = kobject_init_and_add(&mod->mkobj.kobj, &module_ktype, NULL,				   "%s", mod->name);	if (err)		mod_kobject_put(mod); out:	return err;} int mod_sysfs_setup(struct module *mod,		    const struct load_info *info,			   struct kernel_param *kparam,			   unsigned int num_params){	int err; 	err = mod_sysfs_init(mod);	if (err)		goto out; 	mod->holders_dir = kobject_create_and_add("holders", &mod->mkobj.kobj);	if (!mod->holders_dir) {		err = -ENOMEM;		goto out_unreg;	} 	err = module_param_sysfs_setup(mod, kparam, num_params);	if (err)		goto out_unreg_holders; 	err = module_add_modinfo_attrs(mod);	if (err)		goto out_unreg_param; 	err = add_usage_links(mod);	if (err)		goto out_unreg_modinfo_attrs; 	err = add_sect_attrs(mod, info);	if (err)		goto out_del_usage_links; 	err = add_notes_attrs(mod, info);	if (err)		goto out_unreg_sect_attrs; 	return 0; out_unreg_sect_attrs:	remove_sect_attrs(mod);out_del_usage_links:	del_usage_links(mod);out_unreg_modinfo_attrs:	module_remove_modinfo_attrs(mod, -1);out_unreg_param:	module_param_sysfs_remove(mod);out_unreg_holders:	kobject_put(mod->holders_dir);out_unreg:	mod_kobject_put(mod);out:	return err;} static void mod_sysfs_fini(struct module *mod){	remove_notes_attrs(mod);	remove_sect_attrs(mod);	mod_kobject_put(mod);} void mod_sysfs_teardown(struct module *mod){	del_usage_links(mod);	module_remove_modinfo_attrs(mod, -1);	module_param_sysfs_remove(mod);	kobject_put(mod->mkobj.drivers_dir);	kobject_put(mod->holders_dir);	mod_sysfs_fini(mod);} void init_param_lock(struct module *mod){	mutex_init(&mod->param_lock);}