module.c

Linux2.4.20针对三星公司的s3c2410开发板的内核改造。

#include <linux/config.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <asm/module.h>
#include <asm/uaccess.h>
#include <linux/vmalloc.h>
#include <linux/smp_lock.h>
#include <asm/pgalloc.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/kmod.h>
#include <linux/seq_file.h>

/*
 * Originally by Anonymous (as far as I know...)
 * Linux version by Bas Laarhoven <[e-mail]>
 * 0.99.14 version by Jon Tombs <[e-mail]>,
 * Heavily modified by Bjorn Ekwall <[e-mail]> May 1994 (C)
 * Rewritten by Richard Henderson <[e-mail]> Dec 1996
 * Add MOD_INITIALIZING Keith Owens <[e-mail]> Nov 1999
 * Add kallsyms support, Keith Owens <[e-mail]> Apr 2000
 * Add asm/module support, IA64 has special requirements.  Keith Owens <[e-mail]> Sep 2000
 * Fix assorted bugs in module verification.  Keith Owens <[e-mail]> Sep 2000
 * Fix sys_init_module race, Andrew Morton <[e-mail]> Oct 2000
 *     http://www.uwsg.iu.edu/hypermail/linux/kernel/0008.3/0379.html
 * Replace xxx_module_symbol with inter_module_xxx.  Keith Owens <[e-mail]> Oct 2000
 * Add a module list lock for kernel fault race fixing. Alan Cox <[e-mail]>
 *
 * This source is covered by the GNU GPL, the same as all kernel sources.
 */

#if defined(CONFIG_MODULES) || defined(CONFIG_KALLSYMS)

extern struct module_symbol __start___ksymtab[];
extern struct module_symbol __stop___ksymtab[];

extern const struct exception_table_entry __start___ex_table[];
extern const struct exception_table_entry __stop___ex_table[];

extern const char __start___kallsyms[] __attribute__ ((weak));
extern const char __stop___kallsyms[] __attribute__ ((weak));

struct module kernel_module =
{
	size_of_struct:		sizeof(struct module),
	name: 			"",
	uc:	 		{ATOMIC_INIT(1)},
	flags:			MOD_RUNNING,
	syms:			__start___ksymtab,
	ex_table_start:		__start___ex_table,
	ex_table_end:		__stop___ex_table,
	kallsyms_start:		__start___kallsyms,
	kallsyms_end:		__stop___kallsyms,
};

struct module *module_list = &kernel_module;

#endif	/* defined(CONFIG_MODULES) || defined(CONFIG_KALLSYMS) */

/* inter_module functions are always available, even when the kernel is
 * compiled without modules.  Consumers of inter_module_xxx routines
 * will always work, even when both are built into the kernel, this
 * approach removes lots of #ifdefs in mainline code.
 */

static struct list_head ime_list = LIST_HEAD_INIT(ime_list);
static spinlock_t ime_lock = SPIN_LOCK_UNLOCKED;
static int kmalloc_failed;

/*
 *	This lock prevents modifications that might race the kernel fault
 *	fixups. It does not prevent reader walks that the modules code
 *	does. The kernel lock does that.
 *
 *	Since vmalloc fault fixups occur in any context this lock is taken
 *	irqsave at all times.
 */
 
spinlock_t modlist_lock = SPIN_LOCK_UNLOCKED;

/**
 * inter_module_register - register a new set of inter module data.
 * @im_name: an arbitrary string to identify the data, must be unique
 * @owner: module that is registering the data, always use THIS_MODULE
 * @userdata: pointer to arbitrary userdata to be registered
 *
 * Description: Check that the im_name has not already been registered,
 * complain if it has.  For new data, add it to the inter_module_entry
 * list.
 */
void inter_module_register(const char *im_name, struct module *owner, const void *userdata)
{
	struct list_head *tmp;
	struct inter_module_entry *ime, *ime_new;

	if (!(ime_new = kmalloc(sizeof(*ime), GFP_KERNEL))) {
		/* Overloaded kernel, not fatal */
		printk(KERN_ERR
			"Aiee, inter_module_register: cannot kmalloc entry for '%s'\n",
			im_name);
		kmalloc_failed = 1;
		return;
	}
	memset(ime_new, 0, sizeof(*ime_new));
	ime_new->im_name = im_name;
	ime_new->owner = owner;
	ime_new->userdata = userdata;

	spin_lock(&ime_lock);
	list_for_each(tmp, &ime_list) {
		ime = list_entry(tmp, struct inter_module_entry, list);
		if (strcmp(ime->im_name, im_name) == 0) {
			spin_unlock(&ime_lock);
			kfree(ime_new);
			/* Program logic error, fatal */
			printk(KERN_ERR "inter_module_register: duplicate im_name '%s'", im_name);
			BUG();
		}
	}
	list_add(&(ime_new->list), &ime_list);
	spin_unlock(&ime_lock);
}

/**
 * inter_module_unregister - unregister a set of inter module data.
 * @im_name: an arbitrary string to identify the data, must be unique
 *
 * Description: Check that the im_name has been registered, complain if
 * it has not.  For existing data, remove it from the
 * inter_module_entry list.
 */
void inter_module_unregister(const char *im_name)
{
	struct list_head *tmp;
	struct inter_module_entry *ime;

	spin_lock(&ime_lock);
	list_for_each(tmp, &ime_list) {
		ime = list_entry(tmp, struct inter_module_entry, list);
		if (strcmp(ime->im_name, im_name) == 0) {
			list_del(&(ime->list));
			spin_unlock(&ime_lock);
			kfree(ime);
			return;
		}
	}
	spin_unlock(&ime_lock);
	if (kmalloc_failed) {
		printk(KERN_ERR
			"inter_module_unregister: no entry for '%s', "
			"probably caused by previous kmalloc failure\n",
			im_name);
		return;
	}
	else {
		/* Program logic error, fatal */
		printk(KERN_ERR "inter_module_unregister: no entry for '%s'", im_name);
		BUG();
	}
}

/**
 * inter_module_get - return arbitrary userdata from another module.
 * @im_name: an arbitrary string to identify the data, must be unique
 *
 * Description: If the im_name has not been registered, return NULL.
 * Try to increment the use count on the owning module, if that fails
 * then return NULL.  Otherwise return the userdata.
 */
const void *inter_module_get(const char *im_name)
{
	struct list_head *tmp;
	struct inter_module_entry *ime;
	const void *result = NULL;

	spin_lock(&ime_lock);
	list_for_each(tmp, &ime_list) {
		ime = list_entry(tmp, struct inter_module_entry, list);
		if (strcmp(ime->im_name, im_name) == 0) {
			if (try_inc_mod_count(ime->owner))
				result = ime->userdata;
			break;
		}
	}
	spin_unlock(&ime_lock);
	return(result);
}

/**
 * inter_module_get_request - im get with automatic request_module.
 * @im_name: an arbitrary string to identify the data, must be unique
 * @modname: module that is expected to register im_name
 *
 * Description: If inter_module_get fails, do request_module then retry.
 */
const void *inter_module_get_request(const char *im_name, const char *modname)
{
	const void *result = inter_module_get(im_name);
	if (!result) {
		request_module(modname);
		result = inter_module_get(im_name);
	}
	return(result);
}

/**
 * inter_module_put - release use of data from another module.
 * @im_name: an arbitrary string to identify the data, must be unique
 *
 * Description: If the im_name has not been registered, complain,
 * otherwise decrement the use count on the owning module.
 */
void inter_module_put(const char *im_name)
{
	struct list_head *tmp;
	struct inter_module_entry *ime;

	spin_lock(&ime_lock);
	list_for_each(tmp, &ime_list) {
		ime = list_entry(tmp, struct inter_module_entry, list);
		if (strcmp(ime->im_name, im_name) == 0) {
			if (ime->owner)
				__MOD_DEC_USE_COUNT(ime->owner);
			spin_unlock(&ime_lock);
			return;
		}
	}
	spin_unlock(&ime_lock);
	printk(KERN_ERR "inter_module_put: no entry for '%s'", im_name);
	BUG();
}


#if defined(CONFIG_MODULES)	/* The rest of the source */

static long get_mod_name(const char *user_name, char **buf);
static void put_mod_name(char *buf);
struct module *find_module(const char *name);
void free_module(struct module *, int tag_freed);


/*
 * Called at boot time
 */

void __init init_modules(void)
{
	kernel_module.nsyms = __stop___ksymtab - __start___ksymtab;

	arch_init_modules(&kernel_module);
}

/*
 * Copy the name of a module from user space.
 */

static inline long
get_mod_name(const char *user_name, char **buf)
{
	unsigned long page;
	long retval;

	page = __get_free_page(GFP_KERNEL);
	if (!page)
		return -ENOMEM;

	retval = strncpy_from_user((char *)page, user_name, PAGE_SIZE);
	if (retval > 0) {
		if (retval < PAGE_SIZE) {
			*buf = (char *)page;
			return retval;
		}
		retval = -ENAMETOOLONG;
	} else if (!retval)
		retval = -EINVAL;

	free_page(page);
	return retval;
}

static inline void
put_mod_name(char *buf)
{
	free_page((unsigned long)buf);
}

/*
 * Allocate space for a module.
 */

asmlinkage unsigned long
sys_create_module(const char *name_user, size_t size)
{
	char *name;
	long namelen, error;
	struct module *mod;
	unsigned long flags;

	if (!capable(CAP_SYS_MODULE))
		return -EPERM;
	lock_kernel();
	if ((namelen = get_mod_name(name_user, &name)) < 0) {
		error = namelen;
		goto err0;
	}
	if (size < sizeof(struct module)+namelen) {
		error = -EINVAL;
		goto err1;
	}
	if (find_module(name) != NULL) {
		error = -EEXIST;
		goto err1;
	}
	if ((mod = (struct module *)module_map(size)) == NULL) {
		error = -ENOMEM;
		goto err1;
	}

	memset(mod, 0, sizeof(*mod));
	mod->size_of_struct = sizeof(*mod);
	mod->name = (char *)(mod + 1);
	mod->size = size;
	memcpy((char*)(mod+1), name, namelen+1);

	put_mod_name(name);

	spin_lock_irqsave(&modlist_lock, flags);
	mod->next = module_list;
	module_list = mod;	/* link it in */
	spin_unlock_irqrestore(&modlist_lock, flags);

	error = (long) mod;
	goto err0;
err1:
	put_mod_name(name);
err0:
	unlock_kernel();
	return error;
}

/*
 * Initialize a module.
 */

asmlinkage long
sys_init_module(const char *name_user, struct module *mod_user)
{
	struct module mod_tmp, *mod;
	char *name, *n_name, *name_tmp = NULL;
	long namelen, n_namelen, i, error;
	unsigned long mod_user_size;
	struct module_ref *dep;

	if (!capable(CAP_SYS_MODULE))
		return -EPERM;
	lock_kernel();
	if ((namelen = get_mod_name(name_user, &name)) < 0) {
		error = namelen;
		goto err0;
	}
	if ((mod = find_module(name)) == NULL) {
		error = -ENOENT;
		goto err1;
	}

	/* Check module header size.  We allow a bit of slop over the
	   size we are familiar with to cope with a version of insmod
	   for a newer kernel.  But don't over do it. */
	if ((error = get_user(mod_user_size, &mod_user->size_of_struct)) != 0)
		goto err1;
	if (mod_user_size < (unsigned long)&((struct module *)0L)->persist_start
	    || mod_user_size > sizeof(struct module) + 16*sizeof(void*)) {
		printk(KERN_ERR "init_module: Invalid module header size.\n"
		       KERN_ERR "A new version of the modutils is likely "
				"needed.\n");
		error = -EINVAL;
		goto err1;
	}

	/* Hold the current contents while we play with the user's idea
	   of righteousness.  */
	mod_tmp = *mod;
	name_tmp = kmalloc(strlen(mod->name) + 1, GFP_KERNEL);	/* Where's kstrdup()? */
	if (name_tmp == NULL) {
		error = -ENOMEM;
		goto err1;
	}
	strcpy(name_tmp, mod->name);

	error = copy_from_user(mod, mod_user, mod_user_size);
	if (error) {
		error = -EFAULT;
		goto err2;
	}

	/* Sanity check the size of the module.  */
	error = -EINVAL;

	if (mod->size > mod_tmp.size) {
		printk(KERN_ERR "init_module: Size of initialized module "
				"exceeds size of created module.\n");
		goto err2;
	}

	/* Make sure all interesting pointers are sane.  */

	if (!mod_bound(mod->name, namelen, mod)) {
		printk(KERN_ERR "init_module: mod->name out of bounds.\n");
		goto err2;
	}
	if (mod->nsyms && !mod_bound(mod->syms, mod->nsyms, mod)) {
		printk(KERN_ERR "init_module: mod->syms out of bounds.\n");
		goto err2;
	}
	if (mod->ndeps && !mod_bound(mod->deps, mod->ndeps, mod)) {
		printk(KERN_ERR "init_module: mod->deps out of bounds.\n");
		goto err2;
	}
	if (mod->init && !mod_bound(mod->init, 0, mod)) {
		printk(KERN_ERR "init_module: mod->init out of bounds.\n");
		goto err2;
	}
	if (mod->cleanup && !mod_bound(mod->cleanup, 0, mod)) {
		printk(KERN_ERR "init_module: mod->cleanup out of bounds.\n");
		goto err2;
	}
	if (mod->ex_table_start > mod->ex_table_end
	    || (mod->ex_table_start &&
		!((unsigned long)mod->ex_table_start >= ((unsigned long)mod + mod->size_of_struct)
		  && ((unsigned long)mod->ex_table_end
		      < (unsigned long)mod + mod->size)))
	    || (((unsigned long)mod->ex_table_start
		 - (unsigned long)mod->ex_table_end)
		% sizeof(struct exception_table_entry))) {
		printk(KERN_ERR "init_module: mod->ex_table_* invalid.\n");
		goto err2;
	}
	if (mod->flags & ~MOD_AUTOCLEAN) {
		printk(KERN_ERR "init_module: mod->flags invalid.\n");
		goto err2;
	}
	if (mod_member_present(mod, can_unload)
	    && mod->can_unload && !mod_bound(mod->can_unload, 0, mod)) {
		printk(KERN_ERR "init_module: mod->can_unload out of bounds.\n");
		goto err2;
	}
	if (mod_member_present(mod, kallsyms_end)) {
	    if (mod->kallsyms_end &&
		(!mod_bound(mod->kallsyms_start, 0, mod) ||
		 !mod_bound(mod->kallsyms_end, 0, mod))) {
		printk(KERN_ERR "init_module: mod->kallsyms out of bounds.\n");
		goto err2;
	    }
	    if (mod->kallsyms_start > mod->kallsyms_end) {
		printk(KERN_ERR "init_module: mod->kallsyms invalid.\n");
		goto err2;
	    }
	}
	if (mod_member_present(mod, archdata_end)) {
	    if (mod->archdata_end &&
		(!mod_bound(mod->archdata_start, 0, mod) ||
		 !mod_bound(mod->archdata_end, 0, mod))) {
		printk(KERN_ERR "init_module: mod->archdata out of bounds.\n");
		goto err2;
	    }
	    if (mod->archdata_start > mod->archdata_end) {
		printk(KERN_ERR "init_module: mod->archdata invalid.\n");
		goto err2;
	    }
	}
	if (mod_member_present(mod, kernel_data) && mod->kernel_data) {
	    printk(KERN_ERR "init_module: mod->kernel_data must be zero.\n");
	    goto err2;
	}

	/* Check that the user isn't doing something silly with the name.  */

	if ((n_namelen = get_mod_name(mod->name - (unsigned long)mod
				      + (unsigned long)mod_user,
				      &n_name)) < 0) {
		printk(KERN_ERR "init_module: get_mod_name failure.\n");
		error = n_namelen;
		goto err2;
	}
	if (namelen != n_namelen || strcmp(n_name, mod_tmp.name) != 0) {
		printk(KERN_ERR "init_module: changed module name to "
				"`%s' from `%s'\n",
		       n_name, mod_tmp.name);
		goto err3;
	}

	/* Ok, that's about all the sanity we can stomach; copy the rest.  */

	if (copy_from_user((char *)mod+mod_user_size,
			   (char *)mod_user+mod_user_size,
			   mod->size-mod_user_size)) {
		error = -EFAULT;
		goto err3;
	}

	if (module_arch_init(mod))
		goto err3;

	/* On some machines it is necessary to do something here
	   to make the I and D caches consistent.  */
	flush_icache_range((unsigned long)mod, (unsigned long)mod + mod->size);

	mod->next = mod_tmp.next;
	mod->refs = NULL;

	/* Sanity check the module's dependents */
	for (i = 0, dep = mod->deps; i < mod->ndeps; ++i, ++dep) {
		struct module *o, *d = dep->dep;

		/* Make sure the indicated dependencies are really modules.  */
		if (d == mod) {
			printk(KERN_ERR "init_module: self-referential "
					"dependency in mod->deps.\n");
			goto err3;
		}

		/* Scan the current modules for this dependency */
		for (o = module_list; o != &kernel_module && o != d; o = o->next)
			;

		if (o != d) {
			printk(KERN_ERR "init_module: found dependency that is "
				"(no longer?) a module.\n");
			goto err3;
		}
	}

	/* Update module references.  */
	for (i = 0, dep = mod->deps; i < mod->ndeps; ++i, ++dep) {
		struct module *d = dep->dep;

		dep->ref = mod;
		dep->next_ref = d->refs;
		d->refs = dep;
		/* Being referenced by a dependent module counts as a
		   use as far as kmod is concerned.  */
		d->flags |= MOD_USED_ONCE;
	}

	/* Free our temporary memory.  */
	put_mod_name(n_name);
	put_mod_name(name);

	/* Initialize the module.  */
	atomic_set(&mod->uc.usecount,1);
	mod->flags |= MOD_INITIALIZING;
	if (mod->init && (error = mod->init()) != 0) {
		atomic_set(&mod->uc.usecount,0);
		mod->flags &= ~MOD_INITIALIZING;
		if (error > 0)	/* Buggy module */
			error = -EBUSY;
		goto err0;
	}
	atomic_dec(&mod->uc.usecount);

	/* And set it running.  */
	mod->flags = (mod->flags | MOD_RUNNING) & ~MOD_INITIALIZING;
	error = 0;
	goto err0;

err3:
	put_mod_name(n_name);
err2:
	*mod = mod_tmp;
	strcpy((char *)mod->name, name_tmp);	/* We know there is room for this */
err1:
	put_mod_name(name);
err0:
	unlock_kernel();
	kfree(name_tmp);
	return error;
}

static spinlock_t unload_lock = SPIN_LOCK_UNLOCKED;
int try_inc_mod_count(struct module *mod)
{
	int res = 1;
	if (mod) {
		spin_lock(&unload_lock);
		if (mod->flags & MOD_DELETED)
			res = 0;
		else
			__MOD_INC_USE_COUNT(mod);
		spin_unlock(&unload_lock);
	}
	return res;
}

asmlinkage long
sys_delete_module(const char *name_user)
{
	struct module *mod, *next;
	char *name;
	long error;
	int something_changed;

	if (!capable(CAP_SYS_MODULE))
		return -EPERM;

	lock_kernel();
	if (name_user) {
		if ((error = get_mod_name(name_user, &name)) < 0)
			goto out;
		error = -ENOENT;
		if ((mod = find_module(name)) == NULL) {
			put_mod_name(name);
			goto out;
		}
		put_mod_name(name);
		error = -EBUSY;
		if (mod->refs != NULL)
			goto out;

		spin_lock(&unload_lock);
		if (!__MOD_IN_USE(mod)) {
			mod->flags |= MOD_DELETED;
			spin_unlock(&unload_lock);
			free_module(mod, 0);
			error = 0;
		} else {
			spin_unlock(&unload_lock);
		}
		goto out;
	}

	/* Do automatic reaping */
restart:
	something_changed = 0;
	
	for (mod = module_list; mod != &kernel_module; mod = next) {
		next = mod->next;
		spin_lock(&unload_lock);
		if (mod->refs == NULL
		    && (mod->flags & MOD_AUTOCLEAN)
		    && (mod->flags & MOD_RUNNING)
		    && !(mod->flags & MOD_DELETED)
		    && (mod->flags & MOD_USED_ONCE)