module.c

linux 2.6.19 kernel source code before patching

	mod = load_module(umod, len, uargs);
	if (IS_ERR(mod)) {
		mutex_unlock(&module_mutex);
		return PTR_ERR(mod);
	}

	/* Now sew it into the lists.  They won't access us, since
           strong_try_module_get() will fail. */
	stop_machine_run(__link_module, mod, NR_CPUS);

	/* Drop lock so they can recurse */
	mutex_unlock(&module_mutex);

	blocking_notifier_call_chain(&module_notify_list,
			MODULE_STATE_COMING, mod);

	/* Start the module */
	if (mod->init != NULL)
		ret = mod->init();
	if (ret < 0) {
		/* Init routine failed: abort.  Try to protect us from
                   buggy refcounters. */
		mod->state = MODULE_STATE_GOING;
		synchronize_sched();
		if (mod->unsafe)
			printk(KERN_ERR "%s: module is now stuck!\n",
			       mod->name);
		else {
			module_put(mod);
			mutex_lock(&module_mutex);
			free_module(mod);
			mutex_unlock(&module_mutex);
		}
		return ret;
	}

	/* Now it's a first class citizen! */
	mutex_lock(&module_mutex);
	mod->state = MODULE_STATE_LIVE;
	/* Drop initial reference. */
	module_put(mod);
	unwind_remove_table(mod->unwind_info, 1);
	module_free(mod, mod->module_init);
	mod->module_init = NULL;
	mod->init_size = 0;
	mod->init_text_size = 0;
	mutex_unlock(&module_mutex);

	return 0;
}

static inline int within(unsigned long addr, void *start, unsigned long size)
{
	return ((void *)addr >= start && (void *)addr < start + size);
}

#ifdef CONFIG_KALLSYMS
/*
 * This ignores the intensely annoying "mapping symbols" found
 * in ARM ELF files: $a, $t and $d.
 */
static inline int is_arm_mapping_symbol(const char *str)
{
	return str[0] == '$' && strchr("atd", str[1]) 
	       && (str[2] == '\0' || str[2] == '.');
}

static const char *get_ksymbol(struct module *mod,
			       unsigned long addr,
			       unsigned long *size,
			       unsigned long *offset)
{
	unsigned int i, best = 0;
	unsigned long nextval;

	/* At worse, next value is at end of module */
	if (within(addr, mod->module_init, mod->init_size))
		nextval = (unsigned long)mod->module_init+mod->init_text_size;
	else 
		nextval = (unsigned long)mod->module_core+mod->core_text_size;

	/* Scan for closest preceeding symbol, and next symbol. (ELF
           starts real symbols at 1). */
	for (i = 1; i < mod->num_symtab; i++) {
		if (mod->symtab[i].st_shndx == SHN_UNDEF)
			continue;

		/* We ignore unnamed symbols: they're uninformative
		 * and inserted at a whim. */
		if (mod->symtab[i].st_value <= addr
		    && mod->symtab[i].st_value > mod->symtab[best].st_value
		    && *(mod->strtab + mod->symtab[i].st_name) != '\0'
		    && !is_arm_mapping_symbol(mod->strtab + mod->symtab[i].st_name))
			best = i;
		if (mod->symtab[i].st_value > addr
		    && mod->symtab[i].st_value < nextval
		    && *(mod->strtab + mod->symtab[i].st_name) != '\0'
		    && !is_arm_mapping_symbol(mod->strtab + mod->symtab[i].st_name))
			nextval = mod->symtab[i].st_value;
	}

	if (!best)
		return NULL;

	if (size)
		*size = nextval - mod->symtab[best].st_value;
	if (offset)
		*offset = addr - mod->symtab[best].st_value;
	return mod->strtab + mod->symtab[best].st_name;
}

/* For kallsyms to ask for address resolution.  NULL means not found.
   We don't lock, as this is used for oops resolution and races are a
   lesser concern. */
const char *module_address_lookup(unsigned long addr,
				  unsigned long *size,
				  unsigned long *offset,
				  char **modname)
{
	struct module *mod;

	list_for_each_entry(mod, &modules, list) {
		if (within(addr, mod->module_init, mod->init_size)
		    || within(addr, mod->module_core, mod->core_size)) {
			if (modname)
				*modname = mod->name;
			return get_ksymbol(mod, addr, size, offset);
		}
	}
	return NULL;
}

int lookup_module_symbol_name(unsigned long addr, char *symname)
{
	struct module *mod;

	mutex_lock(&module_mutex);
	list_for_each_entry(mod, &modules, list) {
		if (within(addr, mod->module_init, mod->init_size) ||
		    within(addr, mod->module_core, mod->core_size)) {
			const char *sym;

			sym = get_ksymbol(mod, addr, NULL, NULL);
			if (!sym)
				goto out;
			strlcpy(symname, sym, KSYM_NAME_LEN + 1);
			mutex_unlock(&module_mutex);
			return 0;
		}
	}
out:
	mutex_unlock(&module_mutex);
	return -ERANGE;
}

int lookup_module_symbol_attrs(unsigned long addr, unsigned long *size,
			unsigned long *offset, char *modname, char *name)
{
	struct module *mod;

	mutex_lock(&module_mutex);
	list_for_each_entry(mod, &modules, list) {
		if (within(addr, mod->module_init, mod->init_size) ||
		    within(addr, mod->module_core, mod->core_size)) {
			const char *sym;

			sym = get_ksymbol(mod, addr, size, offset);
			if (!sym)
				goto out;
			if (modname)
				strlcpy(modname, mod->name, MODULE_NAME_LEN + 1);
			if (name)
				strlcpy(name, sym, KSYM_NAME_LEN + 1);
			mutex_unlock(&module_mutex);
			return 0;
		}
	}
out:
	mutex_unlock(&module_mutex);
	return -ERANGE;
}

int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
			char *name, char *module_name, int *exported)
{
	struct module *mod;

	mutex_lock(&module_mutex);
	list_for_each_entry(mod, &modules, list) {
		if (symnum < mod->num_symtab) {
			*value = mod->symtab[symnum].st_value;
			*type = mod->symtab[symnum].st_info;
			strlcpy(name, mod->strtab + mod->symtab[symnum].st_name,
				KSYM_NAME_LEN + 1);
			strlcpy(module_name, mod->name, MODULE_NAME_LEN + 1);
			*exported = is_exported(name, mod);
			mutex_unlock(&module_mutex);
			return 0;
		}
		symnum -= mod->num_symtab;
	}
	mutex_unlock(&module_mutex);
	return -ERANGE;
}

static unsigned long mod_find_symname(struct module *mod, const char *name)
{
	unsigned int i;

	for (i = 0; i < mod->num_symtab; i++)
		if (strcmp(name, mod->strtab+mod->symtab[i].st_name) == 0 &&
		    mod->symtab[i].st_info != 'U')
			return mod->symtab[i].st_value;
	return 0;
}

/* Look for this name: can be of form module:name. */
unsigned long module_kallsyms_lookup_name(const char *name)
{
	struct module *mod;
	char *colon;
	unsigned long ret = 0;

	/* Don't lock: we're in enough trouble already. */
	if ((colon = strchr(name, ':')) != NULL) {
		*colon = '\0';
		if ((mod = find_module(name)) != NULL)
			ret = mod_find_symname(mod, colon+1);
		*colon = ':';
	} else {
		list_for_each_entry(mod, &modules, list)
			if ((ret = mod_find_symname(mod, name)) != 0)
				break;
	}
	return ret;
}
#endif /* CONFIG_KALLSYMS */

/* Called by the /proc file system to return a list of modules. */
static void *m_start(struct seq_file *m, loff_t *pos)
{
	struct list_head *i;
	loff_t n = 0;

	mutex_lock(&module_mutex);
	list_for_each(i, &modules) {
		if (n++ == *pos)
			break;
	}
	if (i == &modules)
		return NULL;
	return i;
}

static void *m_next(struct seq_file *m, void *p, loff_t *pos)
{
	struct list_head *i = p;
	(*pos)++;
	if (i->next == &modules)
		return NULL;
	return i->next;
}

static void m_stop(struct seq_file *m, void *p)
{
	mutex_unlock(&module_mutex);
}

static char *taint_flags(unsigned int taints, char *buf)
{
	int bx = 0;

	if (taints) {
		buf[bx++] = '(';
		if (taints & TAINT_PROPRIETARY_MODULE)
			buf[bx++] = 'P';
		if (taints & TAINT_FORCED_MODULE)
			buf[bx++] = 'F';
		/*
		 * TAINT_FORCED_RMMOD: could be added.
		 * TAINT_UNSAFE_SMP, TAINT_MACHINE_CHECK, TAINT_BAD_PAGE don't
		 * apply to modules.
		 */
		buf[bx++] = ')';
	}
	buf[bx] = '\0';

	return buf;
}

static int m_show(struct seq_file *m, void *p)
{
	struct module *mod = list_entry(p, struct module, list);
	char buf[8];

	seq_printf(m, "%s %lu",
		   mod->name, mod->init_size + mod->core_size);
	print_unload_info(m, mod);

	/* Informative for users. */
	seq_printf(m, " %s",
		   mod->state == MODULE_STATE_GOING ? "Unloading":
		   mod->state == MODULE_STATE_COMING ? "Loading":
		   "Live");
	/* Used by oprofile and other similar tools. */
	seq_printf(m, " 0x%p", mod->module_core);

	/* Taints info */
	if (mod->taints)
		seq_printf(m, " %s", taint_flags(mod->taints, buf));

	seq_printf(m, "\n");
	return 0;
}

/* Format: modulename size refcount deps address

   Where refcount is a number or -, and deps is a comma-separated list
   of depends or -.
*/
const struct seq_operations modules_op = {
	.start	= m_start,
	.next	= m_next,
	.stop	= m_stop,
	.show	= m_show
};

/* Given an address, look for it in the module exception tables. */
const struct exception_table_entry *search_module_extables(unsigned long addr)
{
	unsigned long flags;
	const struct exception_table_entry *e = NULL;
	struct module *mod;

	spin_lock_irqsave(&modlist_lock, flags);
	list_for_each_entry(mod, &modules, list) {
		if (mod->num_exentries == 0)
			continue;
				
		e = search_extable(mod->extable,
				   mod->extable + mod->num_exentries - 1,
				   addr);
		if (e)
			break;
	}
	spin_unlock_irqrestore(&modlist_lock, flags);

	/* Now, if we found one, we are running inside it now, hence
           we cannot unload the module, hence no refcnt needed. */
	return e;
}

/*
 * Is this a valid module address?
 */
int is_module_address(unsigned long addr)
{
	unsigned long flags;
	struct module *mod;

	spin_lock_irqsave(&modlist_lock, flags);

	list_for_each_entry(mod, &modules, list) {
		if (within(addr, mod->module_core, mod->core_size)) {
			spin_unlock_irqrestore(&modlist_lock, flags);
			return 1;
		}
	}

	spin_unlock_irqrestore(&modlist_lock, flags);

	return 0;
}


/* Is this a valid kernel address?  We don't grab the lock: we are oopsing. */
struct module *__module_text_address(unsigned long addr)
{
	struct module *mod;

	list_for_each_entry(mod, &modules, list)
		if (within(addr, mod->module_init, mod->init_text_size)
		    || within(addr, mod->module_core, mod->core_text_size))
			return mod;
	return NULL;
}

struct module *module_text_address(unsigned long addr)
{
	struct module *mod;
	unsigned long flags;

	spin_lock_irqsave(&modlist_lock, flags);
	mod = __module_text_address(addr);
	spin_unlock_irqrestore(&modlist_lock, flags);

	return mod;
}

/* Don't grab lock, we're oopsing. */
void print_modules(void)
{
	struct module *mod;
	char buf[8];

	printk("Modules linked in:");
	list_for_each_entry(mod, &modules, list)
		printk(" %s%s", mod->name, taint_flags(mod->taints, buf));
	printk("\n");
}

#ifdef CONFIG_SYSFS
static char *make_driver_name(struct device_driver *drv)
{
	char *driver_name;

	driver_name = kmalloc(strlen(drv->name) + strlen(drv->bus->name) + 2,
			      GFP_KERNEL);
	if (!driver_name)
		return NULL;

	sprintf(driver_name, "%s:%s", drv->bus->name, drv->name);
	return driver_name;
}

static void module_create_drivers_dir(struct module_kobject *mk)
{
	if (!mk || mk->drivers_dir)
		return;

	mk->drivers_dir = kobject_add_dir(&mk->kobj, "drivers");
}

void module_add_driver(struct module *mod, struct device_driver *drv)
{
	char *driver_name;
	int no_warn;
	struct module_kobject *mk = NULL;

	if (!drv)
		return;

	if (mod)
		mk = &mod->mkobj;
	else if (drv->mod_name) {
		struct kobject *mkobj;

		/* Lookup built-in module entry in /sys/modules */
		mkobj = kset_find_obj(&module_subsys, drv->mod_name);
		if (mkobj) {
			mk = container_of(mkobj, struct module_kobject, kobj);
			/* remember our module structure */
			drv->mkobj = mk;
			/* kset_find_obj took a reference */
			kobject_put(mkobj);
		}
	}

	if (!mk)
		return;

	/* Don't check return codes; these calls are idempotent */
	no_warn = sysfs_create_link(&drv->kobj, &mk->kobj, "module");
	driver_name = make_driver_name(drv);
	if (driver_name) {
		module_create_drivers_dir(mk);
		no_warn = sysfs_create_link(mk->drivers_dir, &drv->kobj,
					    driver_name);
		kfree(driver_name);
	}
}
EXPORT_SYMBOL(module_add_driver);

void module_remove_driver(struct device_driver *drv)
{
	struct module_kobject *mk = NULL;
	char *driver_name;

	if (!drv)
		return;

	sysfs_remove_link(&drv->kobj, "module");

	if (drv->owner)
		mk = &drv->owner->mkobj;
	else if (drv->mkobj)
		mk = drv->mkobj;
	if (mk && mk->drivers_dir) {
		driver_name = make_driver_name(drv);
		if (driver_name) {
			sysfs_remove_link(mk->drivers_dir, driver_name);
			kfree(driver_name);
		}
	}
}
EXPORT_SYMBOL(module_r