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#include <linux/scatterlist.h>
 10
 11#include "usbip_common.h"
 12#include "stub.h"
 13
 14#define DRIVER_AUTHOR "Takahiro Hirofuchi"
 15#define DRIVER_DESC "USB/IP Host Driver"
 16
 17struct kmem_cache *stub_priv_cache;
 18
 19/*
 20 * busid_tables defines matching busids that usbip can grab. A user can change
 21 * dynamically what device is locally used and what device is exported to a
 22 * remote host.
 23 */
 24#define MAX_BUSID 16
 25static struct bus_id_priv busid_table[MAX_BUSID];
 26static DEFINE_SPINLOCK(busid_table_lock);
 27
 28static void init_busid_table(void)
 29{
 30	int i;
 31
 32	/*
 33	 * This also sets the bus_table[i].status to
 34	 * STUB_BUSID_OTHER, which is 0.
 35	 */
 36	memset(busid_table, 0, sizeof(busid_table));
 37
 38	for (i = 0; i < MAX_BUSID; i++)
 39		spin_lock_init(&busid_table[i].busid_lock);
 40}
 41
 42/*
 43 * Find the index of the busid by name.
 44 * Must be called with busid_table_lock held.
 45 */
 46static int get_busid_idx(const char *busid)
 47{
 48	int i;
 49	int idx = -1;
 50
 51	for (i = 0; i < MAX_BUSID; i++) {
 52		spin_lock(&busid_table[i].busid_lock);
 53		if (busid_table[i].name[0])
 54			if (!strncmp(busid_table[i].name, busid, BUSID_SIZE)) {
 55				idx = i;
 56				spin_unlock(&busid_table[i].busid_lock);
 57				break;
 58			}
 59		spin_unlock(&busid_table[i].busid_lock);
 60	}
 61	return idx;
 62}
 63
 64/* Returns holding busid_lock. Should call put_busid_priv() to unlock */
 65struct bus_id_priv *get_busid_priv(const char *busid)
 66{
 67	int idx;
 68	struct bus_id_priv *bid = NULL;
 69
 70	spin_lock(&busid_table_lock);
 71	idx = get_busid_idx(busid);
 72	if (idx >= 0) {
 73		bid = &(busid_table[idx]);
 74		/* get busid_lock before returning */
 75		spin_lock(&bid->busid_lock);
 76	}
 77	spin_unlock(&busid_table_lock);
 78
 79	return bid;
 80}
 81
 82void put_busid_priv(struct bus_id_priv *bid)
 83{
 84	if (bid)
 85		spin_unlock(&bid->busid_lock);
 86}
 87
 88static int add_match_busid(char *busid)
 89{
 90	int i;
 91	int ret = -1;
 92
 93	spin_lock(&busid_table_lock);
 94	/* already registered? */
 95	if (get_busid_idx(busid) >= 0) {
 96		ret = 0;
 97		goto out;
 98	}
 99
100	for (i = 0; i < MAX_BUSID; i++) {
101		spin_lock(&busid_table[i].busid_lock);
102		if (!busid_table[i].name[0]) {
103			strlcpy(busid_table[i].name, busid, BUSID_SIZE);
104			if ((busid_table[i].status != STUB_BUSID_ALLOC) &&
105			    (busid_table[i].status != STUB_BUSID_REMOV))
106				busid_table[i].status = STUB_BUSID_ADDED;
107			ret = 0;
108			spin_unlock(&busid_table[i].busid_lock);
109			break;
110		}
111		spin_unlock(&busid_table[i].busid_lock);
112	}
113
114out:
115	spin_unlock(&busid_table_lock);
116
117	return ret;
118}
119
120int del_match_busid(char *busid)
121{
122	int idx;
123	int ret = -1;
124
125	spin_lock(&busid_table_lock);
126	idx = get_busid_idx(busid);
127	if (idx < 0)
128		goto out;
129
130	/* found */
131	ret = 0;
132
133	spin_lock(&busid_table[idx].busid_lock);
134
135	if (busid_table[idx].status == STUB_BUSID_OTHER)
136		memset(busid_table[idx].name, 0, BUSID_SIZE);
137
138	if ((busid_table[idx].status != STUB_BUSID_OTHER) &&
139	    (busid_table[idx].status != STUB_BUSID_ADDED))
140		busid_table[idx].status = STUB_BUSID_REMOV;
141
142	spin_unlock(&busid_table[idx].busid_lock);
143out:
144	spin_unlock(&busid_table_lock);
145
146	return ret;
147}
148
149static ssize_t match_busid_show(struct device_driver *drv, char *buf)
150{
151	int i;
152	char *out = buf;
153
154	spin_lock(&busid_table_lock);
155	for (i = 0; i < MAX_BUSID; i++) {
156		spin_lock(&busid_table[i].busid_lock);
157		if (busid_table[i].name[0])
158			out += sprintf(out, "%s ", busid_table[i].name);
159		spin_unlock(&busid_table[i].busid_lock);
160	}
161	spin_unlock(&busid_table_lock);
162	out += sprintf(out, "\n");
163
164	return out - buf;
165}
166
167static ssize_t match_busid_store(struct device_driver *dev, const char *buf,
168				 size_t count)
169{
170	int len;
171	char busid[BUSID_SIZE];
172
173	if (count < 5)
174		return -EINVAL;
175
176	/* busid needs to include \0 termination */
177	len = strlcpy(busid, buf + 4, BUSID_SIZE);
178	if (sizeof(busid) <= len)
179		return -EINVAL;
180
181	if (!strncmp(buf, "add ", 4)) {
182		if (add_match_busid(busid) < 0)
183			return -ENOMEM;
184
185		pr_debug("add busid %s\n", busid);
186		return count;
187	}
188
189	if (!strncmp(buf, "del ", 4)) {
190		if (del_match_busid(busid) < 0)
191			return -ENODEV;
192
193		pr_debug("del busid %s\n", busid);
194		return count;
195	}
196
197	return -EINVAL;
198}
199static DRIVER_ATTR_RW(match_busid);
200
201static int do_rebind(char *busid, struct bus_id_priv *busid_priv)
202{
203	int ret = 0;
204
205	/* device_attach() callers should hold parent lock for USB */
206	if (busid_priv->udev->dev.parent)
207		device_lock(busid_priv->udev->dev.parent);
208	ret = device_attach(&busid_priv->udev->dev);
209	if (busid_priv->udev->dev.parent)
210		device_unlock(busid_priv->udev->dev.parent);
211	if (ret < 0)
212		dev_err(&busid_priv->udev->dev, "rebind failed\n");
213	return ret;
214}
215
216static void stub_device_rebind(void)
217{
218#if IS_MODULE(CONFIG_USBIP_HOST)
219	struct bus_id_priv *busid_priv;
220	int i;
221
222	/* update status to STUB_BUSID_OTHER so probe ignores the device */
223	spin_lock(&busid_table_lock);
224	for (i = 0; i < MAX_BUSID; i++) {
225		if (busid_table[i].name[0] &&
226		    busid_table[i].shutdown_busid) {
227			busid_priv = &(busid_table[i]);
228			busid_priv->status = STUB_BUSID_OTHER;
229		}
230	}
231	spin_unlock(&busid_table_lock);
232
233	/* now run rebind - no need to hold locks. driver files are removed */
234	for (i = 0; i < MAX_BUSID; i++) {
235		if (busid_table[i].name[0] &&
236		    busid_table[i].shutdown_busid) {
237			busid_priv = &(busid_table[i]);
238			do_rebind(busid_table[i].name, busid_priv);
239		}
240	}
241#endif
242}
243
244static ssize_t rebind_store(struct device_driver *dev, const char *buf,
245				 size_t count)
246{
247	int ret;
248	int len;
249	struct bus_id_priv *bid;
250
251	/* buf length should be less that BUSID_SIZE */
252	len = strnlen(buf, BUSID_SIZE);
253
254	if (!(len < BUSID_SIZE))
255		return -EINVAL;
256
257	bid = get_busid_priv(buf);
258	if (!bid)
259		return -ENODEV;
260
261	/* mark the device for deletion so probe ignores it during rescan */
262	bid->status = STUB_BUSID_OTHER;
263	/* release the busid lock */
264	put_busid_priv(bid);
265
266	ret = do_rebind((char *) buf, bid);
267	if (ret < 0)
268		return ret;
269
270	/* delete device from busid_table */
271	del_match_busid((char *) buf);
272
273	return count;
274}
275
276static DRIVER_ATTR_WO(rebind);
277
278static struct stub_priv *stub_priv_pop_from_listhead(struct list_head *listhead)
279{
280	struct stub_priv *priv, *tmp;
281
282	list_for_each_entry_safe(priv, tmp, listhead, list) {
283		list_del_init(&priv->list);
284		return priv;
285	}
286
287	return NULL;
288}
289
290void stub_free_priv_and_urb(struct stub_priv *priv)
291{
292	struct urb *urb;
293	int i;
294
295	for (i = 0; i < priv->num_urbs; i++) {
296		urb = priv->urbs[i];
297
298		if (!urb)
299			return;
300
301		kfree(urb->setup_packet);
302		urb->setup_packet = NULL;
303
304
305		if (urb->transfer_buffer && !priv->sgl) {
306			kfree(urb->transfer_buffer);
307			urb->transfer_buffer = NULL;
308		}
309
310		if (urb->num_sgs) {
311			sgl_free(urb->sg);
312			urb->sg = NULL;
313			urb->num_sgs = 0;
314		}
315
316		usb_free_urb(urb);
317	}
318	if (!list_empty(&priv->list))
319		list_del(&priv->list);
320	if (priv->sgl)
321		sgl_free(priv->sgl);
322	kfree(priv->urbs);
323	kmem_cache_free(stub_priv_cache, priv);
324}
325
326static struct stub_priv *stub_priv_pop(struct stub_device *sdev)
327{
328	unsigned long flags;
329	struct stub_priv *priv;
330
331	spin_lock_irqsave(&sdev->priv_lock, flags);
332
333	priv = stub_priv_pop_from_listhead(&sdev->priv_init);
334	if (priv)
335		goto done;
336
337	priv = stub_priv_pop_from_listhead(&sdev->priv_tx);
338	if (priv)
339		goto done;
340
341	priv = stub_priv_pop_from_listhead(&sdev->priv_free);
342
343done:
344	spin_unlock_irqrestore(&sdev->priv_lock, flags);
345
346	return priv;
347}
348
349void stub_device_cleanup_urbs(struct stub_device *sdev)
350{
351	struct stub_priv *priv;
352	int i;
353
354	dev_dbg(&sdev->udev->dev, "Stub device cleaning up urbs\n");
355
356	while ((priv = stub_priv_pop(sdev))) {
357		for (i = 0; i < priv->num_urbs; i++)
358			usb_kill_urb(priv->urbs[i]);
359
360		stub_free_priv_and_urb(priv);
361	}
362}
363
364static int __init usbip_host_init(void)
365{
366	int ret;
367
368	init_busid_table();
369
370	stub_priv_cache = KMEM_CACHE(stub_priv, SLAB_HWCACHE_ALIGN);
371	if (!stub_priv_cache) {
372		pr_err("kmem_cache_create failed\n");
373		return -ENOMEM;
374	}
375
376	ret = usb_register_device_driver(&stub_driver, THIS_MODULE);
377	if (ret) {
378		pr_err("usb_register failed %d\n", ret);
379		goto err_usb_register;
380	}
381
382	ret = driver_create_file(&stub_driver.drvwrap.driver,
383				 &driver_attr_match_busid);
384	if (ret) {
385		pr_err("driver_create_file failed\n");
386		goto err_create_file;
387	}
388
389	ret = driver_create_file(&stub_driver.drvwrap.driver,
390				 &driver_attr_rebind);
391	if (ret) {
392		pr_err("driver_create_file failed\n");
393		goto err_create_file;
394	}
395
396	return ret;
397
398err_create_file:
399	usb_deregister_device_driver(&stub_driver);
400err_usb_register:
401	kmem_cache_destroy(stub_priv_cache);
402	return ret;
403}
404
405static void __exit usbip_host_exit(void)
406{
407	driver_remove_file(&stub_driver.drvwrap.driver,
408			   &driver_attr_match_busid);
409
410	driver_remove_file(&stub_driver.drvwrap.driver,
411			   &driver_attr_rebind);
412
413	/*
414	 * deregister() calls stub_disconnect() for all devices. Device
415	 * specific data is cleared in stub_disconnect().
416	 */
417	usb_deregister_device_driver(&stub_driver);
418
419	/* initiate scan to attach devices */
420	stub_device_rebind();
421
422	kmem_cache_destroy(stub_priv_cache);
423}
424
425module_init(usbip_host_init);
426module_exit(usbip_host_exit);
427
428MODULE_AUTHOR(DRIVER_AUTHOR);
429MODULE_DESCRIPTION(DRIVER_DESC);
430MODULE_LICENSE("GPL");