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