[linux-2.6-block.git] / drivers / usb / mon / mon_main.c

/*
 * The USB Monitor, inspired by Dave Harding's USBMon.
 *
 * mon_main.c: Main file, module initiation and exit, registrations, etc.
 *
 * Copyright (C) 2005 Pete Zaitcev (zaitcev@redhat.com)
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/usb.h>
#include <linux/debugfs.h>
#include <linux/smp_lock.h>
#include <linux/notifier.h>

#include "usb_mon.h"
#include "../core/hcd.h"

static void mon_submit(struct usb_bus *ubus, struct urb *urb);
static void mon_complete(struct usb_bus *ubus, struct urb *urb);
static void mon_stop(struct mon_bus *mbus);
static void mon_dissolve(struct mon_bus *mbus, struct usb_bus *ubus);
static void mon_bus_drop(struct kref *r);
static void mon_bus_init(struct dentry *mondir, struct usb_bus *ubus);

DECLARE_MUTEX(mon_lock);

static struct dentry *mon_dir;		/* /dbg/usbmon */
static LIST_HEAD(mon_buses);		/* All buses we know: struct mon_bus */

/*
 * Link a reader into the bus.
 *
 * This must be called with mon_lock taken because of mbus->ref.
 */
void mon_reader_add(struct mon_bus *mbus, struct mon_reader *r)
{
	unsigned long flags;
	struct usb_bus *ubus;

	spin_lock_irqsave(&mbus->lock, flags);
	if (mbus->nreaders == 0) {
		ubus = mbus->u_bus;
		if (ubus->monitored) {
			/*
			 * Something is really broken, refuse to go on and
			 * possibly corrupt ops pointers or worse.
			 */
			printk(KERN_ERR TAG ": bus %d is already monitored\n",
			    ubus->busnum);
			spin_unlock_irqrestore(&mbus->lock, flags);
			return;
		}
		ubus->monitored = 1;
	}
	mbus->nreaders++;
	list_add_tail(&r->r_link, &mbus->r_list);
	spin_unlock_irqrestore(&mbus->lock, flags);

	kref_get(&mbus->ref);
}

/*
 * Unlink reader from the bus.
 *
 * This is called with mon_lock taken, so we can decrement mbus->ref.
 */
void mon_reader_del(struct mon_bus *mbus, struct mon_reader *r)
{
	unsigned long flags;

	spin_lock_irqsave(&mbus->lock, flags);
	list_del(&r->r_link);
	--mbus->nreaders;
	if (mbus->nreaders == 0)
		mon_stop(mbus);
	spin_unlock_irqrestore(&mbus->lock, flags);

	kref_put(&mbus->ref, mon_bus_drop);
}

/*
 */
static void mon_submit(struct usb_bus *ubus, struct urb *urb)
{
	struct mon_bus *mbus;
	unsigned long flags;
	struct list_head *pos;
	struct mon_reader *r;

	mbus = ubus->mon_bus;
	if (mbus == NULL)
		goto out_unlocked;

	spin_lock_irqsave(&mbus->lock, flags);
	if (mbus->nreaders == 0)
		goto out_locked;

	list_for_each (pos, &mbus->r_list) {
		r = list_entry(pos, struct mon_reader, r_link);
		r->rnf_submit(r->r_data, urb);
	}

	spin_unlock_irqrestore(&mbus->lock, flags);
	return;

out_locked:
	spin_unlock_irqrestore(&mbus->lock, flags);
out_unlocked:
	return;
}

/*
 */
static void mon_submit_error(struct usb_bus *ubus, struct urb *urb, int err)
{
	struct mon_bus *mbus;

	mbus = ubus->mon_bus;
	if (mbus == NULL)
		goto out_unlocked;

	/*
	 * XXX Capture the error code and the 'E' event.
	 */

	return;

out_unlocked:
	return;
}

/*
 */
static void mon_complete(struct usb_bus *ubus, struct urb *urb)
{
	struct mon_bus *mbus;
	unsigned long flags;
	struct list_head *pos;
	struct mon_reader *r;

	mbus = ubus->mon_bus;
	if (mbus == NULL) {
		/*
		 * This should not happen.
		 * At this point we do not even know the bus number...
		 */
		printk(KERN_ERR TAG ": Null mon bus in URB, pipe 0x%x\n",
		    urb->pipe);
		return;
	}

	spin_lock_irqsave(&mbus->lock, flags);
	list_for_each (pos, &mbus->r_list) {
		r = list_entry(pos, struct mon_reader, r_link);
		r->rnf_complete(r->r_data, urb);
	}
	spin_unlock_irqrestore(&mbus->lock, flags);
}

/* int (*unlink_urb) (struct urb *urb, int status); */

/*
 * Stop monitoring.
 * Obviously this must be well locked, so no need to play with mb's.
 */
static void mon_stop(struct mon_bus *mbus)
{
	struct usb_bus *ubus = mbus->u_bus;

	/*
	 * A stop can be called for a dissolved mon_bus in case of
	 * a reader staying across an rmmod foo_hcd.
	 */
	if (ubus != NULL) {
		ubus->monitored = 0;
		mb();
	}
}

/*
 * Add a USB bus (usually by a modprobe foo-hcd)
 *
 * This does not return an error code because the core cannot care less
 * if monitoring is not established.
 */
static void mon_bus_add(struct usb_bus *ubus)
{
	mon_bus_init(mon_dir, ubus);
}

/*
 * Remove a USB bus (either from rmmod foo-hcd or from a hot-remove event).
 */
static void mon_bus_remove(struct usb_bus *ubus)
{
	struct mon_bus *mbus = ubus->mon_bus;

	down(&mon_lock);
	list_del(&mbus->bus_link);
	debugfs_remove(mbus->dent_t);
	debugfs_remove(mbus->dent_s);

	mon_dissolve(mbus, ubus);
	kref_put(&mbus->ref, mon_bus_drop);
	up(&mon_lock);
}

static int mon_notify(struct notifier_block *self, unsigned long action,
		      void *dev)
{
	switch (action) {
	case USB_BUS_ADD:
		mon_bus_add(dev);
		break;
	case USB_BUS_REMOVE:
		mon_bus_remove(dev);
	}
	return NOTIFY_OK;
}

static struct notifier_block mon_nb = {
	.notifier_call = 	mon_notify,
};

/*
 * Ops
 */
static struct usb_mon_operations mon_ops_0 = {
	.urb_submit =	mon_submit,
	.urb_submit_error = mon_submit_error,
	.urb_complete =	mon_complete,
};

/*
 * Tear usb_bus and mon_bus apart.
 */
static void mon_dissolve(struct mon_bus *mbus, struct usb_bus *ubus)
{

	/*
	 * Never happens, but...
	 */
	if (ubus->monitored) {
		printk(KERN_ERR TAG ": bus %d is dissolved while monitored\n",
		    ubus->busnum);
		ubus->monitored = 0;
		mb();
	}

	ubus->mon_bus = NULL;
	mbus->u_bus = NULL;
	mb();
	// usb_bus_put(ubus);
}

/*
 */
static void mon_bus_drop(struct kref *r)
{
	struct mon_bus *mbus = container_of(r, struct mon_bus, ref);
	kfree(mbus);
}

/*
 * Initialize a bus for us:
 *  - allocate mon_bus
 *  - refcount USB bus struct
 *  - link
 */
static void mon_bus_init(struct dentry *mondir, struct usb_bus *ubus)
{
	struct dentry *d;
	struct mon_bus *mbus;
	enum { NAMESZ = 10 };
	char name[NAMESZ];
	int rc;

	if ((mbus = kmalloc(sizeof(struct mon_bus), GFP_KERNEL)) == NULL)
		goto err_alloc;
	memset(mbus, 0, sizeof(struct mon_bus));
	kref_init(&mbus->ref);
	spin_lock_init(&mbus->lock);
	INIT_LIST_HEAD(&mbus->r_list);

	/*
	 * This usb_bus_get here is superfluous, because we receive
	 * a notification if usb_bus is about to be removed.
	 */
	// usb_bus_get(ubus);
	mbus->u_bus = ubus;
	ubus->mon_bus = mbus;

	rc = snprintf(name, NAMESZ, "%dt", ubus->busnum);
	if (rc <= 0 || rc >= NAMESZ)
		goto err_print_t;
	d = debugfs_create_file(name, 0600, mondir, mbus, &mon_fops_text);
	if (d == NULL)
		goto err_create_t;
	mbus->dent_t = d;

	rc = snprintf(name, NAMESZ, "%ds", ubus->busnum);
	if (rc <= 0 || rc >= NAMESZ)
		goto err_print_s;
	d = debugfs_create_file(name, 0600, mondir, mbus, &mon_fops_stat);
	if (d == NULL)
		goto err_create_s;
	mbus->dent_s = d;

	down(&mon_lock);
	list_add_tail(&mbus->bus_link, &mon_buses);
	up(&mon_lock);
	return;

err_create_s:
err_print_s:
	debugfs_remove(mbus->dent_t);
err_create_t:
err_print_t:
	kfree(mbus);
err_alloc:
	return;
}

static int __init mon_init(void)
{
	struct usb_bus *ubus;
	struct dentry *mondir;

	mondir = debugfs_create_dir("usbmon", NULL);
	if (IS_ERR(mondir)) {
		printk(KERN_NOTICE TAG ": debugfs is not available\n");
		return -ENODEV;
	}
	if (mondir == NULL) {
		printk(KERN_NOTICE TAG ": unable to create usbmon directory\n");
		return -ENODEV;
	}
	mon_dir = mondir;

	if (usb_mon_register(&mon_ops_0) != 0) {
		printk(KERN_NOTICE TAG ": unable to register with the core\n");
		debugfs_remove(mondir);
		return -ENODEV;
	}
	// MOD_INC_USE_COUNT(which_module?);

	usb_register_notify(&mon_nb);

	down(&usb_bus_list_lock);
	list_for_each_entry (ubus, &usb_bus_list, bus_list) {
		mon_bus_init(mondir, ubus);
	}
	up(&usb_bus_list_lock);
	return 0;
}

static void __exit mon_exit(void)
{
	struct mon_bus *mbus;
	struct list_head *p;

	usb_unregister_notify(&mon_nb);
	usb_mon_deregister();

	down(&mon_lock);
	while (!list_empty(&mon_buses)) {
		p = mon_buses.next;
		mbus = list_entry(p, struct mon_bus, bus_link);
		list_del(p);

		debugfs_remove(mbus->dent_t);
		debugfs_remove(mbus->dent_s);

		/*
		 * This never happens, because the open/close paths in
		 * file level maintain module use counters and so rmmod fails
		 * before reaching here. However, better be safe...
		 */
		if (mbus->nreaders) {
			printk(KERN_ERR TAG
			    ": Outstanding opens (%d) on usb%d, leaking...\n",
			    mbus->nreaders, mbus->u_bus->busnum);
			atomic_set(&mbus->ref.refcount, 2);	/* Force leak */
		}

		mon_dissolve(mbus, mbus->u_bus);
		kref_put(&mbus->ref, mon_bus_drop);
	}
	up(&mon_lock);

	debugfs_remove(mon_dir);
}

module_init(mon_init);
module_exit(mon_exit);

MODULE_LICENSE("GPL");
Commit	Line	Data
1da177e4 LT	1	/*
	2	* The USB Monitor, inspired by Dave Harding's USBMon.
	3	*
	4	* mon_main.c: Main file, module initiation and exit, registrations, etc.
da5ca008 PZ	5	*
da5ca008 PZ	6	* Copyright (C) 2005 Pete Zaitcev (zaitcev@redhat.com)
1da177e4 LT	7	*/
	8
	9	#include <linux/kernel.h>
	10	#include <linux/module.h>
	11	#include <linux/usb.h>
	12	#include <linux/debugfs.h>
	13	#include <linux/smp_lock.h>
72adaa96	14	#include <linux/notifier.h>
1da177e4 LT	15
	16	#include "usb_mon.h"
	17	#include "../core/hcd.h"
	18
	19	static void mon_submit(struct usb_bus ubus, struct urb urb);
	20	static void mon_complete(struct usb_bus ubus, struct urb urb);
	21	static void mon_stop(struct mon_bus *mbus);
	22	static void mon_dissolve(struct mon_bus mbus, struct usb_bus ubus);
	23	static void mon_bus_drop(struct kref *r);
	24	static void mon_bus_init(struct dentry mondir, struct usb_bus ubus);
	25
	26	DECLARE_MUTEX(mon_lock);
	27
	28	static struct dentry mon_dir; / /dbg/usbmon */
	29	static LIST_HEAD(mon_buses); /* All buses we know: struct mon_bus */
	30
	31	/*
	32	* Link a reader into the bus.
	33	*
	34	* This must be called with mon_lock taken because of mbus->ref.
	35	*/
	36	void mon_reader_add(struct mon_bus mbus, struct mon_reader r)
	37	{
	38	unsigned long flags;
	39	struct usb_bus *ubus;
	40
	41	spin_lock_irqsave(&mbus->lock, flags);
	42	if (mbus->nreaders == 0) {
	43	ubus = mbus->u_bus;
	44	if (ubus->monitored) {
	45	/*
	46	* Something is really broken, refuse to go on and
	47	* possibly corrupt ops pointers or worse.
	48	*/
	49	printk(KERN_ERR TAG ": bus %d is already monitored\n",
	50	ubus->busnum);
	51	spin_unlock_irqrestore(&mbus->lock, flags);
	52	return;
	53	}
	54	ubus->monitored = 1;
	55	}
	56	mbus->nreaders++;
	57	list_add_tail(&r->r_link, &mbus->r_list);
	58	spin_unlock_irqrestore(&mbus->lock, flags);
	59
	60	kref_get(&mbus->ref);
	61	}
	62
	63	/*
	64	* Unlink reader from the bus.
	65	*
	66	* This is called with mon_lock taken, so we can decrement mbus->ref.
	67	*/
	68	void mon_reader_del(struct mon_bus mbus, struct mon_reader r)
	69	{
	70	unsigned long flags;
	71
	72	spin_lock_irqsave(&mbus->lock, flags);
	73	list_del(&r->r_link);
	74	--mbus->nreaders;
	75	if (mbus->nreaders == 0)
	76	mon_stop(mbus);
	77	spin_unlock_irqrestore(&mbus->lock, flags);
	78
79	kref_put(&mbus->ref, mon_bus_drop);
80	}
81
82	/*
83	*/
84	static void mon_submit(struct usb_bus ubus, struct urb urb)
85	{
86	struct mon_bus *mbus;
87	unsigned long flags;
88	struct list_head *pos;
89	struct mon_reader *r;
90
91	mbus = ubus->mon_bus;
92	if (mbus == NULL)
93	goto out_unlocked;
94
95	spin_lock_irqsave(&mbus->lock, flags);
96	if (mbus->nreaders == 0)
97	goto out_locked;
98
99	list_for_each (pos, &mbus->r_list) {
100	r = list_entry(pos, struct mon_reader, r_link);
101	r->rnf_submit(r->r_data, urb);
102	}
103
104	spin_unlock_irqrestore(&mbus->lock, flags);
105	return;
106
107	out_locked:
108	spin_unlock_irqrestore(&mbus->lock, flags);
109	out_unlocked:
110	return;
111	}
112
113	/*
114	*/
115	static void mon_submit_error(struct usb_bus ubus, struct urb urb, int err)
116	{
117	struct mon_bus *mbus;
118
119	mbus = ubus->mon_bus;
120	if (mbus == NULL)
121	goto out_unlocked;
122
123	/*
124	* XXX Capture the error code and the 'E' event.
125	*/
126
127	return;
128
129	out_unlocked:
130	return;
131	}
132
133	/*
134	*/
135	static void mon_complete(struct usb_bus ubus, struct urb urb)
136	{
137	struct mon_bus *mbus;
138	unsigned long flags;
139	struct list_head *pos;
140	struct mon_reader *r;
141
142	mbus = ubus->mon_bus;
143	if (mbus == NULL) {
144	/*
145	* This should not happen.
146	* At this point we do not even know the bus number...
147	*/
148	printk(KERN_ERR TAG ": Null mon bus in URB, pipe 0x%x\n",
149	urb->pipe);
150	return;
151	}
152
153	spin_lock_irqsave(&mbus->lock, flags);
154	list_for_each (pos, &mbus->r_list) {
155	r = list_entry(pos, struct mon_reader, r_link);
156	r->rnf_complete(r->r_data, urb);
157	}
158	spin_unlock_irqrestore(&mbus->lock, flags);
159	}
160
161	/* int (unlink_urb) (struct urb urb, int status); */
162
163	/*
164	* Stop monitoring.
165	* Obviously this must be well locked, so no need to play with mb's.
166	*/
167	static void mon_stop(struct mon_bus *mbus)
168	{
169	struct usb_bus *ubus = mbus->u_bus;
170
171	/*
172	* A stop can be called for a dissolved mon_bus in case of
173	* a reader staying across an rmmod foo_hcd.
174	*/
175	if (ubus != NULL) {
176	ubus->monitored = 0;
177	mb();
178	}
179	}
180
181	/*
182	* Add a USB bus (usually by a modprobe foo-hcd)
183	*
184	* This does not return an error code because the core cannot care less
185	* if monitoring is not established.
186	*/
187	static void mon_bus_add(struct usb_bus *ubus)
188	{
189	mon_bus_init(mon_dir, ubus);
190	}
191
192	/*
193	* Remove a USB bus (either from rmmod foo-hcd or from a hot-remove event).
194	*/
195	static void mon_bus_remove(struct usb_bus *ubus)
196	{
197	struct mon_bus *mbus = ubus->mon_bus;
198
199	down(&mon_lock);
200	list_del(&mbus->bus_link);
201	debugfs_remove(mbus->dent_t);
202	debugfs_remove(mbus->dent_s);
203
204	mon_dissolve(mbus, ubus);
205	kref_put(&mbus->ref, mon_bus_drop);
206	up(&mon_lock);
207	}
208
72adaa96 GKH	209	static int mon_notify(struct notifier_block *self, unsigned long action,
	210	void *dev)
	211	{
	212	switch (action) {
	213	case USB_BUS_ADD:
	214	mon_bus_add(dev);
	215	break;
	216	case USB_BUS_REMOVE:
	217	mon_bus_remove(dev);
	218	}
	219	return NOTIFY_OK;
	220	}
	221
	222	static struct notifier_block mon_nb = {
	223	.notifier_call = mon_notify,
	224	};
	225
1da177e4 LT	226	/*
	227	* Ops
	228	*/
	229	static struct usb_mon_operations mon_ops_0 = {
	230	.urb_submit = mon_submit,
	231	.urb_submit_error = mon_submit_error,
	232	.urb_complete = mon_complete,
1da177e4 LT	233	};
	234
	235	/*
	236	* Tear usb_bus and mon_bus apart.
	237	*/
	238	static void mon_dissolve(struct mon_bus mbus, struct usb_bus ubus)
	239	{
	240
	241	/*
	242	* Never happens, but...
	243	*/
	244	if (ubus->monitored) {
	245	printk(KERN_ERR TAG ": bus %d is dissolved while monitored\n",
	246	ubus->busnum);
	247	ubus->monitored = 0;
	248	mb();
	249	}
	250
	251	ubus->mon_bus = NULL;
	252	mbus->u_bus = NULL;
	253	mb();
	254	// usb_bus_put(ubus);
	255	}
	256
	257	/*
	258	*/
	259	static void mon_bus_drop(struct kref *r)
	260	{
	261	struct mon_bus *mbus = container_of(r, struct mon_bus, ref);
	262	kfree(mbus);
	263	}
	264
	265	/*
	266	* Initialize a bus for us:
	267	* - allocate mon_bus
	268	* - refcount USB bus struct
	269	* - link
	270	*/
	271	static void mon_bus_init(struct dentry mondir, struct usb_bus ubus)
	272	{
	273	struct dentry *d;
	274	struct mon_bus *mbus;
	275	enum { NAMESZ = 10 };
	276	char name[NAMESZ];
	277	int rc;
	278
	279	if ((mbus = kmalloc(sizeof(struct mon_bus), GFP_KERNEL)) == NULL)
	280	goto err_alloc;
	281	memset(mbus, 0, sizeof(struct mon_bus));
	282	kref_init(&mbus->ref);
	283	spin_lock_init(&mbus->lock);
	284	INIT_LIST_HEAD(&mbus->r_list);
	285
	286	/*
	287	* This usb_bus_get here is superfluous, because we receive
	288	* a notification if usb_bus is about to be removed.
	289	*/
	290	// usb_bus_get(ubus);
	291	mbus->u_bus = ubus;
	292	ubus->mon_bus = mbus;
	293
	294	rc = snprintf(name, NAMESZ, "%dt", ubus->busnum);
	295	if (rc <= 0 \|\| rc >= NAMESZ)
	296	goto err_print_t;
297	d = debugfs_create_file(name, 0600, mondir, mbus, &mon_fops_text);
298	if (d == NULL)
299	goto err_create_t;
300	mbus->dent_t = d;
301
302	rc = snprintf(name, NAMESZ, "%ds", ubus->busnum);
303	if (rc <= 0 \|\| rc >= NAMESZ)
304	goto err_print_s;
305	d = debugfs_create_file(name, 0600, mondir, mbus, &mon_fops_stat);
306	if (d == NULL)
307	goto err_create_s;
308	mbus->dent_s = d;
309
310	down(&mon_lock);
311	list_add_tail(&mbus->bus_link, &mon_buses);
312	up(&mon_lock);
313	return;
314
315	err_create_s:
316	err_print_s:
317	debugfs_remove(mbus->dent_t);
318	err_create_t:
319	err_print_t:
320	kfree(mbus);
321	err_alloc:
322	return;
323	}
324
325	static int __init mon_init(void)
326	{
327	struct usb_bus *ubus;
328	struct dentry *mondir;
329
330	mondir = debugfs_create_dir("usbmon", NULL);
331	if (IS_ERR(mondir)) {
da5ca008	332	printk(KERN_NOTICE TAG ": debugfs is not available\n");
1da177e4 LT	333	return -ENODEV;
	334	}
	335	if (mondir == NULL) {
	336	printk(KERN_NOTICE TAG ": unable to create usbmon directory\n");
	337	return -ENODEV;
	338	}
	339	mon_dir = mondir;
	340
	341	if (usb_mon_register(&mon_ops_0) != 0) {
	342	printk(KERN_NOTICE TAG ": unable to register with the core\n");
	343	debugfs_remove(mondir);
	344	return -ENODEV;
	345	}
	346	// MOD_INC_USE_COUNT(which_module?);
	347
72adaa96 GKH	348	usb_register_notify(&mon_nb);
72adaa96 GKH	349
1da177e4 LT	350	down(&usb_bus_list_lock);
	351	list_for_each_entry (ubus, &usb_bus_list, bus_list) {
	352	mon_bus_init(mondir, ubus);
	353	}
	354	up(&usb_bus_list_lock);
	355	return 0;
	356	}
	357
	358	static void __exit mon_exit(void)
	359	{
	360	struct mon_bus *mbus;
	361	struct list_head *p;
	362
72adaa96	363	usb_unregister_notify(&mon_nb);
1da177e4 LT	364	usb_mon_deregister();
	365
	366	down(&mon_lock);
	367	while (!list_empty(&mon_buses)) {
	368	p = mon_buses.next;
	369	mbus = list_entry(p, struct mon_bus, bus_link);
	370	list_del(p);
	371
	372	debugfs_remove(mbus->dent_t);
	373	debugfs_remove(mbus->dent_s);
	374
	375	/*
	376	* This never happens, because the open/close paths in
	377	* file level maintain module use counters and so rmmod fails
	378	* before reaching here. However, better be safe...
	379	*/
	380	if (mbus->nreaders) {
	381	printk(KERN_ERR TAG
	382	": Outstanding opens (%d) on usb%d, leaking...\n",
	383	mbus->nreaders, mbus->u_bus->busnum);
	384	atomic_set(&mbus->ref.refcount, 2); /* Force leak */
	385	}
	386
	387	mon_dissolve(mbus, mbus->u_bus);
	388	kref_put(&mbus->ref, mon_bus_drop);
	389	}
	390	up(&mon_lock);
	391
	392	debugfs_remove(mon_dir);
	393	}
	394
	395	module_init(mon_init);
	396	module_exit(mon_exit);
	397
	398	MODULE_LICENSE("GPL");