xref: /linux/drivers/usb/usbip/stub_main.c (revision 06d07429858317ded2db7986113a9e0129cd599b)
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 
17 struct 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
25 static struct bus_id_priv busid_table[MAX_BUSID];
26 static DEFINE_SPINLOCK(busid_table_lock);
27 
init_busid_table(void)28 static 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  */
get_busid_idx(const char * busid)46 static 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 */
get_busid_priv(const char * busid)65 struct 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 
put_busid_priv(struct bus_id_priv * bid)82 void put_busid_priv(struct bus_id_priv *bid)
83 {
84 	if (bid)
85 		spin_unlock(&bid->busid_lock);
86 }
87 
add_match_busid(char * busid)88 static 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 			strscpy(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 
114 out:
115 	spin_unlock(&busid_table_lock);
116 
117 	return ret;
118 }
119 
del_match_busid(char * busid)120 int 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);
143 out:
144 	spin_unlock(&busid_table_lock);
145 
146 	return ret;
147 }
148 
match_busid_show(struct device_driver * drv,char * buf)149 static 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 
match_busid_store(struct device_driver * dev,const char * buf,size_t count)167 static ssize_t match_busid_store(struct device_driver *dev, const char *buf,
168 				 size_t count)
169 {
170 	char busid[BUSID_SIZE];
171 
172 	if (count < 5)
173 		return -EINVAL;
174 
175 	/* busid needs to include \0 termination */
176 	if (strscpy(busid, buf + 4, BUSID_SIZE) < 0)
177 		return -EINVAL;
178 
179 	if (!strncmp(buf, "add ", 4)) {
180 		if (add_match_busid(busid) < 0)
181 			return -ENOMEM;
182 
183 		pr_debug("add busid %s\n", busid);
184 		return count;
185 	}
186 
187 	if (!strncmp(buf, "del ", 4)) {
188 		if (del_match_busid(busid) < 0)
189 			return -ENODEV;
190 
191 		pr_debug("del busid %s\n", busid);
192 		return count;
193 	}
194 
195 	return -EINVAL;
196 }
197 static DRIVER_ATTR_RW(match_busid);
198 
do_rebind(char * busid,struct bus_id_priv * busid_priv)199 static int do_rebind(char *busid, struct bus_id_priv *busid_priv)
200 {
201 	int ret = 0;
202 
203 	/* device_attach() callers should hold parent lock for USB */
204 	if (busid_priv->udev->dev.parent)
205 		device_lock(busid_priv->udev->dev.parent);
206 	ret = device_attach(&busid_priv->udev->dev);
207 	if (busid_priv->udev->dev.parent)
208 		device_unlock(busid_priv->udev->dev.parent);
209 	if (ret < 0)
210 		dev_err(&busid_priv->udev->dev, "rebind failed\n");
211 	return ret;
212 }
213 
stub_device_rebind(void)214 static void stub_device_rebind(void)
215 {
216 #if IS_MODULE(CONFIG_USBIP_HOST)
217 	struct bus_id_priv *busid_priv;
218 	int i;
219 
220 	/* update status to STUB_BUSID_OTHER so probe ignores the device */
221 	spin_lock(&busid_table_lock);
222 	for (i = 0; i < MAX_BUSID; i++) {
223 		if (busid_table[i].name[0] &&
224 		    busid_table[i].shutdown_busid) {
225 			busid_priv = &(busid_table[i]);
226 			busid_priv->status = STUB_BUSID_OTHER;
227 		}
228 	}
229 	spin_unlock(&busid_table_lock);
230 
231 	/* now run rebind - no need to hold locks. driver files are removed */
232 	for (i = 0; i < MAX_BUSID; i++) {
233 		if (busid_table[i].name[0] &&
234 		    busid_table[i].shutdown_busid) {
235 			busid_priv = &(busid_table[i]);
236 			do_rebind(busid_table[i].name, busid_priv);
237 		}
238 	}
239 #endif
240 }
241 
rebind_store(struct device_driver * dev,const char * buf,size_t count)242 static ssize_t rebind_store(struct device_driver *dev, const char *buf,
243 				 size_t count)
244 {
245 	int ret;
246 	int len;
247 	struct bus_id_priv *bid;
248 
249 	/* buf length should be less that BUSID_SIZE */
250 	len = strnlen(buf, BUSID_SIZE);
251 
252 	if (!(len < BUSID_SIZE))
253 		return -EINVAL;
254 
255 	bid = get_busid_priv(buf);
256 	if (!bid)
257 		return -ENODEV;
258 
259 	/* mark the device for deletion so probe ignores it during rescan */
260 	bid->status = STUB_BUSID_OTHER;
261 	/* release the busid lock */
262 	put_busid_priv(bid);
263 
264 	ret = do_rebind((char *) buf, bid);
265 	if (ret < 0)
266 		return ret;
267 
268 	/* delete device from busid_table */
269 	del_match_busid((char *) buf);
270 
271 	return count;
272 }
273 
274 static DRIVER_ATTR_WO(rebind);
275 
stub_priv_pop_from_listhead(struct list_head * listhead)276 static struct stub_priv *stub_priv_pop_from_listhead(struct list_head *listhead)
277 {
278 	struct stub_priv *priv, *tmp;
279 
280 	list_for_each_entry_safe(priv, tmp, listhead, list) {
281 		list_del_init(&priv->list);
282 		return priv;
283 	}
284 
285 	return NULL;
286 }
287 
stub_free_priv_and_urb(struct stub_priv * priv)288 void stub_free_priv_and_urb(struct stub_priv *priv)
289 {
290 	struct urb *urb;
291 	int i;
292 
293 	for (i = 0; i < priv->num_urbs; i++) {
294 		urb = priv->urbs[i];
295 
296 		if (!urb)
297 			return;
298 
299 		kfree(urb->setup_packet);
300 		urb->setup_packet = NULL;
301 
302 
303 		if (urb->transfer_buffer && !priv->sgl) {
304 			kfree(urb->transfer_buffer);
305 			urb->transfer_buffer = NULL;
306 		}
307 
308 		if (urb->num_sgs) {
309 			sgl_free(urb->sg);
310 			urb->sg = NULL;
311 			urb->num_sgs = 0;
312 		}
313 
314 		usb_free_urb(urb);
315 	}
316 	if (!list_empty(&priv->list))
317 		list_del(&priv->list);
318 	if (priv->sgl)
319 		sgl_free(priv->sgl);
320 	kfree(priv->urbs);
321 	kmem_cache_free(stub_priv_cache, priv);
322 }
323 
stub_priv_pop(struct stub_device * sdev)324 static struct stub_priv *stub_priv_pop(struct stub_device *sdev)
325 {
326 	unsigned long flags;
327 	struct stub_priv *priv;
328 
329 	spin_lock_irqsave(&sdev->priv_lock, flags);
330 
331 	priv = stub_priv_pop_from_listhead(&sdev->priv_init);
332 	if (priv)
333 		goto done;
334 
335 	priv = stub_priv_pop_from_listhead(&sdev->priv_tx);
336 	if (priv)
337 		goto done;
338 
339 	priv = stub_priv_pop_from_listhead(&sdev->priv_free);
340 
341 done:
342 	spin_unlock_irqrestore(&sdev->priv_lock, flags);
343 
344 	return priv;
345 }
346 
stub_device_cleanup_urbs(struct stub_device * sdev)347 void stub_device_cleanup_urbs(struct stub_device *sdev)
348 {
349 	struct stub_priv *priv;
350 	int i;
351 
352 	dev_dbg(&sdev->udev->dev, "Stub device cleaning up urbs\n");
353 
354 	while ((priv = stub_priv_pop(sdev))) {
355 		for (i = 0; i < priv->num_urbs; i++)
356 			usb_kill_urb(priv->urbs[i]);
357 
358 		stub_free_priv_and_urb(priv);
359 	}
360 }
361 
usbip_host_init(void)362 static int __init usbip_host_init(void)
363 {
364 	int ret;
365 
366 	init_busid_table();
367 
368 	stub_priv_cache = KMEM_CACHE(stub_priv, SLAB_HWCACHE_ALIGN);
369 	if (!stub_priv_cache) {
370 		pr_err("kmem_cache_create failed\n");
371 		return -ENOMEM;
372 	}
373 
374 	ret = usb_register_device_driver(&stub_driver, THIS_MODULE);
375 	if (ret) {
376 		pr_err("usb_register failed %d\n", ret);
377 		goto err_usb_register;
378 	}
379 
380 	ret = driver_create_file(&stub_driver.driver,
381 				 &driver_attr_match_busid);
382 	if (ret) {
383 		pr_err("driver_create_file failed\n");
384 		goto err_create_file;
385 	}
386 
387 	ret = driver_create_file(&stub_driver.driver,
388 				 &driver_attr_rebind);
389 	if (ret) {
390 		pr_err("driver_create_file failed\n");
391 		goto err_create_file;
392 	}
393 
394 	return ret;
395 
396 err_create_file:
397 	usb_deregister_device_driver(&stub_driver);
398 err_usb_register:
399 	kmem_cache_destroy(stub_priv_cache);
400 	return ret;
401 }
402 
usbip_host_exit(void)403 static void __exit usbip_host_exit(void)
404 {
405 	driver_remove_file(&stub_driver.driver,
406 			   &driver_attr_match_busid);
407 
408 	driver_remove_file(&stub_driver.driver,
409 			   &driver_attr_rebind);
410 
411 	/*
412 	 * deregister() calls stub_disconnect() for all devices. Device
413 	 * specific data is cleared in stub_disconnect().
414 	 */
415 	usb_deregister_device_driver(&stub_driver);
416 
417 	/* initiate scan to attach devices */
418 	stub_device_rebind();
419 
420 	kmem_cache_destroy(stub_priv_cache);
421 }
422 
423 module_init(usbip_host_init);
424 module_exit(usbip_host_exit);
425 
426 MODULE_AUTHOR(DRIVER_AUTHOR);
427 MODULE_DESCRIPTION(DRIVER_DESC);
428 MODULE_LICENSE("GPL");
429