| // 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_KALLSYMS |
| struct 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 void 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; |
| |
| /* 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; |
| |
| /* Setup section attributes. */ |
| sect_attrs->grp.name = "sections"; |
| sect_attrs->grp.bin_attrs = (void *)sect_attrs + size[0]; |
| |
| sect_attrs->nsections = 0; |
| sattr = §_attrs->attrs[0]; |
| gattr = §_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) |
| 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; |
| |
| if (sysfs_create_group(&mod->mkobj.kobj, §_attrs->grp)) |
| goto out; |
| |
| mod->sect_attrs = sect_attrs; |
| return; |
| out: |
| free_sect_attrs(sect_attrs); |
| } |
| |
| 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, |
| ¬es_attrs->attrs[i]); |
| kobject_put(notes_attrs->dir); |
| } |
| kfree(notes_attrs); |
| } |
| |
| static void 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; |
| |
| /* failed to create section attributes, so can't create notes */ |
| if (!mod->sect_attrs) |
| return; |
| |
| /* 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; |
| |
| notes_attrs = kzalloc(struct_size(notes_attrs, attrs, notes), |
| GFP_KERNEL); |
| if (!notes_attrs) |
| return; |
| |
| notes_attrs->notes = notes; |
| nattr = ¬es_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) |
| goto out; |
| |
| for (i = 0; i < notes; ++i) |
| if (sysfs_create_bin_file(notes_attrs->dir, |
| ¬es_attrs->attrs[i])) |
| goto out; |
| |
| mod->notes_attrs = notes_attrs; |
| return; |
| |
| out: |
| free_notes_attrs(notes_attrs, i); |
| } |
| |
| 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 void add_sect_attrs(struct module *mod, const struct load_info *info) { } |
| static inline void remove_sect_attrs(struct module *mod) { } |
| static inline void add_notes_attrs(struct module *mod, const struct load_info *info) { } |
| 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; |
| |
| add_sect_attrs(mod, info); |
| add_notes_attrs(mod, info); |
| |
| return 0; |
| |
| 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); |
| } |