1 files changed, 436 insertions, 0 deletions

diff --git a/kernel/module/sysfs.c b/kernel/module/sysfs.c
new file mode 100644
index 0000000000..c921bf0440
--- /dev/null
+++ b/kernel/module/sysfs.c
@@ -0,0 +1,436 @@
+// 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 = &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)
+			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, &sect_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[];
+};
+
+static ssize_t module_notes_read(struct file *filp, struct kobject *kobj,
+				 struct bin_attribute *bin_attr,
+				 char *buf, loff_t pos, size_t count)
+{
+	/*
+	 * The caller checked the pos and count against our size.
+	 */
+	memcpy(buf, bin_attr->private + pos, count);
+	return count;
+}
+
+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 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 = &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 = module_notes_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,
+					  &notes_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);
+}