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fb506e31b3
The normal bin_attrs field can now handle const pointers. This makes the _new variant unnecessary. Switch all users back. Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> Link: https://lore.kernel.org/r/20250530-sysfs-const-bin_attr-final-v3-4-724bfcf05b99@weissschuh.net Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
440 lines
9.8 KiB
C
440 lines
9.8 KiB
C
// 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 <corbet@lwn.net>
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*/
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#ifdef CONFIG_KALLSYMS
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struct module_sect_attrs {
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struct attribute_group grp;
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struct bin_attribute 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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const struct bin_attribute *battr,
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char *buf, loff_t pos, size_t count)
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{
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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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? battr->private : 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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const struct bin_attribute *const *bin_attr;
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for (bin_attr = sect_attrs->grp.bin_attrs; *bin_attr; bin_attr++)
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kfree((*bin_attr)->attr.name);
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kfree(sect_attrs->grp.bin_attrs);
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kfree(sect_attrs);
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}
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static int add_sect_attrs(struct module *mod, const struct load_info *info)
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{
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struct module_sect_attrs *sect_attrs;
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const struct bin_attribute **gattr;
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struct bin_attribute *sattr;
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unsigned int nloaded = 0, i;
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int ret;
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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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sect_attrs = kzalloc(struct_size(sect_attrs, attrs, nloaded), GFP_KERNEL);
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if (!sect_attrs)
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return -ENOMEM;
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gattr = kcalloc(nloaded + 1, sizeof(*gattr), GFP_KERNEL);
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if (!gattr) {
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kfree(sect_attrs);
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return -ENOMEM;
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}
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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 = gattr;
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sattr = §_attrs->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);
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sattr->attr.name =
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kstrdup(info->secstrings + sec->sh_name, GFP_KERNEL);
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if (!sattr->attr.name) {
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ret = -ENOMEM;
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goto out;
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}
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sattr->read = module_sect_read;
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sattr->private = (void *)sec->sh_addr;
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sattr->size = MODULE_SECT_READ_SIZE;
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sattr->attr.mode = 0400;
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*(gattr++) = sattr++;
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}
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ret = sysfs_create_group(&mod->mkobj.kobj, §_attrs->grp);
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if (ret)
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goto out;
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mod->sect_attrs = sect_attrs;
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return 0;
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out:
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free_sect_attrs(sect_attrs);
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return ret;
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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 attribute_group grp;
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struct bin_attribute attrs[];
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};
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static void free_notes_attrs(struct module_notes_attrs *notes_attrs)
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{
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kfree(notes_attrs->grp.bin_attrs);
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kfree(notes_attrs);
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}
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static int 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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const struct bin_attribute **gattr;
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struct bin_attribute *nattr;
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int ret;
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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 0;
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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 -ENOMEM;
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gattr = kcalloc(notes + 1, sizeof(*gattr), GFP_KERNEL);
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if (!gattr) {
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kfree(notes_attrs);
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return -ENOMEM;
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}
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notes_attrs->grp.name = "notes";
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notes_attrs->grp.bin_attrs = gattr;
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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].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 = sysfs_bin_attr_simple_read;
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*(gattr++) = nattr++;
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}
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++loaded;
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}
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ret = sysfs_create_group(&mod->mkobj.kobj, ¬es_attrs->grp);
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if (ret)
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goto out;
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mod->notes_attrs = notes_attrs;
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return 0;
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out:
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free_notes_attrs(notes_attrs);
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return ret;
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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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sysfs_remove_group(&mod->mkobj.kobj,
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&mod->notes_attrs->grp);
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/*
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* We are positive that no one is using any notes attrs
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* at this point. Deallocate immediately.
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*/
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free_notes_attrs(mod->notes_attrs);
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mod->notes_attrs = NULL;
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}
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}
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#else /* !CONFIG_KALLSYMS */
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static inline int add_sect_attrs(struct module *mod, const struct load_info *info)
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{
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return 0;
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}
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static inline void remove_sect_attrs(struct module *mod) { }
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static inline int add_notes_attrs(struct module *mod, const struct load_info *info)
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{
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return 0;
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}
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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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const 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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const 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_kset) {
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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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err = add_sect_attrs(mod, info);
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if (err)
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goto out_del_usage_links;
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err = add_notes_attrs(mod, info);
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if (err)
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goto out_unreg_sect_attrs;
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return 0;
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out_unreg_sect_attrs:
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remove_sect_attrs(mod);
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out_del_usage_links:
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del_usage_links(mod);
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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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