1// SPDX-License-Identifier: GPL-2.0+
  2/*
  3 * Copyright (C) 2003-2008 Takahiro Hirofuchi
  4 */
  5
  6#include <linux/string.h>
  7#include <linux/module.h>
  8#include <linux/device.h>
  9
 10#include "usbip_common.h"
 11#include "stub.h"
 12
 13#define DRIVER_AUTHOR "Takahiro Hirofuchi"
 14#define DRIVER_DESC "USB/IP Host Driver"
 15
 16struct kmem_cache *stub_priv_cache;
 17
 18/*
 19 * busid_tables defines matching busids that usbip can grab. A user can change
 20 * dynamically what device is locally used and what device is exported to a
 21 * remote host.
 22 */
 23#define MAX_BUSID 16
 24static struct bus_id_priv busid_table[MAX_BUSID];
 25static spinlock_t busid_table_lock;
 26
 27static void init_busid_table(void)
 28{
 29	int i;
 30
 31	/*
 32	 * This also sets the bus_table[i].status to
 33	 * STUB_BUSID_OTHER, which is 0.
 34	 */
 35	memset(busid_table, 0, sizeof(busid_table));
 36
 37	spin_lock_init(&busid_table_lock);
 38
 39	for (i = 0; i < MAX_BUSID; i++)
 40		spin_lock_init(&busid_table[i].busid_lock);
 41}
 42
 43/*
 44 * Find the index of the busid by name.
 45 * Must be called with busid_table_lock held.
 46 */
 47static int get_busid_idx(const char *busid)
 48{
 49	int i;
 50	int idx = -1;
 51
 52	for (i = 0; i < MAX_BUSID; i++) {
 53		spin_lock(&busid_table[i].busid_lock);
 54		if (busid_table[i].name[0])
 55			if (!strncmp(busid_table[i].name, busid, BUSID_SIZE)) {
 56				idx = i;
 57				spin_unlock(&busid_table[i].busid_lock);
 58				break;
 59			}
 60		spin_unlock(&busid_table[i].busid_lock);
 61	}
 62	return idx;
 63}
 64
 65/* Returns holding busid_lock. Should call put_busid_priv() to unlock */
 66struct bus_id_priv *get_busid_priv(const char *busid)
 67{
 68	int idx;
 69	struct bus_id_priv *bid = NULL;
 70
 71	spin_lock(&busid_table_lock);
 72	idx = get_busid_idx(busid);
 73	if (idx >= 0) {
 74		bid = &(busid_table[idx]);
 75		/* get busid_lock before returning */
 76		spin_lock(&bid->busid_lock);
 77	}
 78	spin_unlock(&busid_table_lock);
 79
 80	return bid;
 81}
 82
 83void put_busid_priv(struct bus_id_priv *bid)
 84{
 85	if (bid)
 86		spin_unlock(&bid->busid_lock);
 87}
 88
 89static int add_match_busid(char *busid)
 90{
 91	int i;
 92	int ret = -1;
 93
 94	spin_lock(&busid_table_lock);
 95	/* already registered? */
 96	if (get_busid_idx(busid) >= 0) {
 97		ret = 0;
 98		goto out;
 99	}
100
101	for (i = 0; i < MAX_BUSID; i++) {
102		spin_lock(&busid_table[i].busid_lock);
103		if (!busid_table[i].name[0]) {
104			strlcpy(busid_table[i].name, busid, BUSID_SIZE);
105			if ((busid_table[i].status != STUB_BUSID_ALLOC) &&
106			    (busid_table[i].status != STUB_BUSID_REMOV))
107				busid_table[i].status = STUB_BUSID_ADDED;
108			ret = 0;
109			spin_unlock(&busid_table[i].busid_lock);
110			break;
111		}
112		spin_unlock(&busid_table[i].busid_lock);
113	}
114
115out:
116	spin_unlock(&busid_table_lock);
117
118	return ret;
119}
120
121int del_match_busid(char *busid)
122{
123	int idx;
124	int ret = -1;
125
126	spin_lock(&busid_table_lock);
127	idx = get_busid_idx(busid);
128	if (idx < 0)
129		goto out;
130
131	/* found */
132	ret = 0;
133
134	spin_lock(&busid_table[idx].busid_lock);
135
136	if (busid_table[idx].status == STUB_BUSID_OTHER)
137		memset(busid_table[idx].name, 0, BUSID_SIZE);
138
139	if ((busid_table[idx].status != STUB_BUSID_OTHER) &&
140	    (busid_table[idx].status != STUB_BUSID_ADDED))
141		busid_table[idx].status = STUB_BUSID_REMOV;
142
143	spin_unlock(&busid_table[idx].busid_lock);
144out:
145	spin_unlock(&busid_table_lock);
146
147	return ret;
148}
149
150static ssize_t match_busid_show(struct device_driver *drv, char *buf)
151{
152	int i;
153	char *out = buf;
154
155	spin_lock(&busid_table_lock);
156	for (i = 0; i < MAX_BUSID; i++) {
157		spin_lock(&busid_table[i].busid_lock);
158		if (busid_table[i].name[0])
159			out += sprintf(out, "%s ", busid_table[i].name);
160		spin_unlock(&busid_table[i].busid_lock);
161	}
162	spin_unlock(&busid_table_lock);
163	out += sprintf(out, "\n");
164
165	return out - buf;
166}
167
168static ssize_t match_busid_store(struct device_driver *dev, const char *buf,
169				 size_t count)
170{
171	int len;
172	char busid[BUSID_SIZE];
173
174	if (count < 5)
175		return -EINVAL;
176
177	/* busid needs to include \0 termination */
178	len = strlcpy(busid, buf + 4, BUSID_SIZE);
179	if (sizeof(busid) <= len)
180		return -EINVAL;
181
182	if (!strncmp(buf, "add ", 4)) {
183		if (add_match_busid(busid) < 0)
184			return -ENOMEM;
185
186		pr_debug("add busid %s\n", busid);
187		return count;
188	}
189
190	if (!strncmp(buf, "del ", 4)) {
191		if (del_match_busid(busid) < 0)
192			return -ENODEV;
193
194		pr_debug("del busid %s\n", busid);
195		return count;
196	}
197
198	return -EINVAL;
199}
200static DRIVER_ATTR_RW(match_busid);
201
202static int do_rebind(char *busid, struct bus_id_priv *busid_priv)
203{
204	int ret;
205
206	/* device_attach() callers should hold parent lock for USB */
207	if (busid_priv->udev->dev.parent)
208		device_lock(busid_priv->udev->dev.parent);
209	ret = device_attach(&busid_priv->udev->dev);
210	if (busid_priv->udev->dev.parent)
211		device_unlock(busid_priv->udev->dev.parent);
212	if (ret < 0) {
213		dev_err(&busid_priv->udev->dev, "rebind failed\n");
214		return ret;
215	}
216	return 0;
217}
218
219static void stub_device_rebind(void)
220{
221#if IS_MODULE(CONFIG_USBIP_HOST)
222	struct bus_id_priv *busid_priv;
223	int i;
224
225	/* update status to STUB_BUSID_OTHER so probe ignores the device */
226	spin_lock(&busid_table_lock);
227	for (i = 0; i < MAX_BUSID; i++) {
228		if (busid_table[i].name[0] &&
229		    busid_table[i].shutdown_busid) {
230			busid_priv = &(busid_table[i]);
231			busid_priv->status = STUB_BUSID_OTHER;
232		}
233	}
234	spin_unlock(&busid_table_lock);
235
236	/* now run rebind - no need to hold locks. driver files are removed */
237	for (i = 0; i < MAX_BUSID; i++) {
238		if (busid_table[i].name[0] &&
239		    busid_table[i].shutdown_busid) {
240			busid_priv = &(busid_table[i]);
241			do_rebind(busid_table[i].name, busid_priv);
242		}
243	}
244#endif
245}
246
247static ssize_t rebind_store(struct device_driver *dev, const char *buf,
248				 size_t count)
249{
250	int ret;
251	int len;
252	struct bus_id_priv *bid;
253
254	/* buf length should be less that BUSID_SIZE */
255	len = strnlen(buf, BUSID_SIZE);
256
257	if (!(len < BUSID_SIZE))
258		return -EINVAL;
259
260	bid = get_busid_priv(buf);
261	if (!bid)
262		return -ENODEV;
263
264	/* mark the device for deletion so probe ignores it during rescan */
265	bid->status = STUB_BUSID_OTHER;
266	/* release the busid lock */
267	put_busid_priv(bid);
268
269	ret = do_rebind((char *) buf, bid);
270	if (ret < 0)
271		return ret;
272
273	/* delete device from busid_table */
274	del_match_busid((char *) buf);
275
276	return count;
277}
278
279static DRIVER_ATTR_WO(rebind);
280
281static struct stub_priv *stub_priv_pop_from_listhead(struct list_head *listhead)
282{
283	struct stub_priv *priv, *tmp;
284
285	list_for_each_entry_safe(priv, tmp, listhead, list) {
286		list_del(&priv->list);
287		return priv;
288	}
289
290	return NULL;
291}
292
293static struct stub_priv *stub_priv_pop(struct stub_device *sdev)
294{
295	unsigned long flags;
296	struct stub_priv *priv;
297
298	spin_lock_irqsave(&sdev->priv_lock, flags);
299
300	priv = stub_priv_pop_from_listhead(&sdev->priv_init);
301	if (priv)
302		goto done;
303
304	priv = stub_priv_pop_from_listhead(&sdev->priv_tx);
305	if (priv)
306		goto done;
307
308	priv = stub_priv_pop_from_listhead(&sdev->priv_free);
309
310done:
311	spin_unlock_irqrestore(&sdev->priv_lock, flags);
312
313	return priv;
314}
315
316void stub_device_cleanup_urbs(struct stub_device *sdev)
317{
318	struct stub_priv *priv;
319	struct urb *urb;
320
321	dev_dbg(&sdev->udev->dev, "Stub device cleaning up urbs\n");
322
323	while ((priv = stub_priv_pop(sdev))) {
324		urb = priv->urb;
325		dev_dbg(&sdev->udev->dev, "free urb seqnum %lu\n",
326			priv->seqnum);
327		usb_kill_urb(urb);
328
329		kmem_cache_free(stub_priv_cache, priv);
330
331		kfree(urb->transfer_buffer);
332		urb->transfer_buffer = NULL;
333
334		kfree(urb->setup_packet);
335		urb->setup_packet = NULL;
336
337		usb_free_urb(urb);
338	}
339}
340
341static int __init usbip_host_init(void)
342{
343	int ret;
344
345	init_busid_table();
346
347	stub_priv_cache = KMEM_CACHE(stub_priv, SLAB_HWCACHE_ALIGN);
348	if (!stub_priv_cache) {
349		pr_err("kmem_cache_create failed\n");
350		return -ENOMEM;
351	}
352
353	ret = usb_register_device_driver(&stub_driver, THIS_MODULE);
354	if (ret) {
355		pr_err("usb_register failed %d\n", ret);
356		goto err_usb_register;
357	}
358
359	ret = driver_create_file(&stub_driver.drvwrap.driver,
360				 &driver_attr_match_busid);
361	if (ret) {
362		pr_err("driver_create_file failed\n");
363		goto err_create_file;
364	}
365
366	ret = driver_create_file(&stub_driver.drvwrap.driver,
367				 &driver_attr_rebind);
368	if (ret) {
369		pr_err("driver_create_file failed\n");
370		goto err_create_file;
371	}
372
373	return ret;
374
375err_create_file:
376	usb_deregister_device_driver(&stub_driver);
377err_usb_register:
378	kmem_cache_destroy(stub_priv_cache);
379	return ret;
380}
381
382static void __exit usbip_host_exit(void)
383{
384	driver_remove_file(&stub_driver.drvwrap.driver,
385			   &driver_attr_match_busid);
386
387	driver_remove_file(&stub_driver.drvwrap.driver,
388			   &driver_attr_rebind);
389
390	/*
391	 * deregister() calls stub_disconnect() for all devices. Device
392	 * specific data is cleared in stub_disconnect().
393	 */
394	usb_deregister_device_driver(&stub_driver);
395
396	/* initiate scan to attach devices */
397	stub_device_rebind();
398
399	kmem_cache_destroy(stub_priv_cache);
400}
401
402module_init(usbip_host_init);
403module_exit(usbip_host_exit);
404
405MODULE_AUTHOR(DRIVER_AUTHOR);
406MODULE_DESCRIPTION(DRIVER_DESC);
407MODULE_LICENSE("GPL");