1// SPDX-License-Identifier: GPL-2.0
2/*
3 * The USB Monitor, inspired by Dave Harding's USBMon.
4 *
5 * This is a text format reader.
6 */
7
8#include <linux/kernel.h>
9#include <linux/list.h>
10#include <linux/usb.h>
11#include <linux/slab.h>
12#include <linux/sched/signal.h>
13#include <linux/time.h>
14#include <linux/ktime.h>
15#include <linux/export.h>
16#include <linux/mutex.h>
17#include <linux/debugfs.h>
18#include <linux/scatterlist.h>
19#include <linux/uaccess.h>
20
21#include "usb_mon.h"
22
23/*
24 * No, we do not want arbitrarily long data strings.
25 * Use the binary interface if you want to capture bulk data!
26 */
27#define DATA_MAX 32
28
29/*
30 * Defined by USB 2.0 clause 9.3, table 9.2.
31 */
32#define SETUP_MAX 8
33
34/*
35 * This limit exists to prevent OOMs when the user process stops reading.
36 * If usbmon were available to unprivileged processes, it might be open
37 * to a local DoS. But we have to keep to root in order to prevent
38 * password sniffing from HID devices.
39 */
40#define EVENT_MAX (4*PAGE_SIZE / sizeof(struct mon_event_text))
41
42/*
43 * Potentially unlimited number; we limit it for similar allocations.
44 * The usbfs limits this to 128, but we're not quite as generous.
45 */
46#define ISODESC_MAX 5
47
48#define PRINTF_DFL 250 /* with 5 ISOs segs */
49
50struct mon_iso_desc {
51 int status;
52 unsigned int offset;
53 unsigned int length; /* Unsigned here, signed in URB. Historic. */
54};
55
56struct mon_event_text {
57 struct list_head e_link;
58 int type; /* submit, complete, etc. */
59 unsigned long id; /* From pointer, most of the time */
60 unsigned int tstamp;
61 int busnum;
62 char devnum;
63 char epnum;
64 char is_in;
65 char xfertype;
66 int length; /* Depends on type: xfer length or act length */
67 int status;
68 int interval;
69 int start_frame;
70 int error_count;
71 char setup_flag;
72 char data_flag;
73 int numdesc; /* Full number */
74 struct mon_iso_desc isodesc[ISODESC_MAX];
75 unsigned char setup[SETUP_MAX];
76 unsigned char data[DATA_MAX];
77};
78
79#define SLAB_NAME_SZ 30
80struct mon_reader_text {
81 struct kmem_cache *e_slab;
82 int nevents;
83 struct list_head e_list;
84 struct mon_reader r; /* In C, parent class can be placed anywhere */
85
86 wait_queue_head_t wait;
87 int printf_size;
88 size_t printf_offset;
89 size_t printf_togo;
90 char *printf_buf;
91 struct mutex printf_lock;
92
93 char slab_name[SLAB_NAME_SZ];
94};
95
96static struct dentry *mon_dir; /* Usually /sys/kernel/debug/usbmon */
97
98static void mon_text_ctor(void *);
99
100struct mon_text_ptr {
101 int cnt, limit;
102 char *pbuf;
103};
104
105static struct mon_event_text *
106 mon_text_read_wait(struct mon_reader_text *rp, struct file *file);
107static void mon_text_read_head_t(struct mon_reader_text *rp,
108 struct mon_text_ptr *p, const struct mon_event_text *ep);
109static void mon_text_read_head_u(struct mon_reader_text *rp,
110 struct mon_text_ptr *p, const struct mon_event_text *ep);
111static void mon_text_read_statset(struct mon_reader_text *rp,
112 struct mon_text_ptr *p, const struct mon_event_text *ep);
113static void mon_text_read_intstat(struct mon_reader_text *rp,
114 struct mon_text_ptr *p, const struct mon_event_text *ep);
115static void mon_text_read_isostat(struct mon_reader_text *rp,
116 struct mon_text_ptr *p, const struct mon_event_text *ep);
117static void mon_text_read_isodesc(struct mon_reader_text *rp,
118 struct mon_text_ptr *p, const struct mon_event_text *ep);
119static void mon_text_read_data(struct mon_reader_text *rp,
120 struct mon_text_ptr *p, const struct mon_event_text *ep);
121
122/*
123 * mon_text_submit
124 * mon_text_complete
125 *
126 * May be called from an interrupt.
127 *
128 * This is called with the whole mon_bus locked, so no additional lock.
129 */
130
131static inline char mon_text_get_setup(struct mon_event_text *ep,
132 struct urb *urb, char ev_type, struct mon_bus *mbus)
133{
134
135 if (ep->xfertype != USB_ENDPOINT_XFER_CONTROL || ev_type != 'S')
136 return '-';
137
138 if (urb->setup_packet == NULL)
139 return 'Z'; /* '0' would be not as pretty. */
140
141 memcpy(to: ep->setup, from: urb->setup_packet, SETUP_MAX);
142 return 0;
143}
144
145static inline char mon_text_get_data(struct mon_event_text *ep, struct urb *urb,
146 int len, char ev_type, struct mon_bus *mbus)
147{
148 void *src;
149
150 if (len <= 0)
151 return 'L';
152 if (len >= DATA_MAX)
153 len = DATA_MAX;
154
155 if (ep->is_in) {
156 if (ev_type != 'C')
157 return '<';
158 } else {
159 if (ev_type != 'S')
160 return '>';
161 }
162
163 if (urb->num_sgs == 0) {
164 src = urb->transfer_buffer;
165 if (src == NULL)
166 return 'Z'; /* '0' would be not as pretty. */
167 } else {
168 struct scatterlist *sg = urb->sg;
169
170 if (PageHighMem(page: sg_page(sg)))
171 return 'D';
172
173 /* For the text interface we copy only the first sg buffer */
174 len = min_t(int, sg->length, len);
175 src = sg_virt(sg);
176 }
177
178 memcpy(to: ep->data, from: src, len);
179 return 0;
180}
181
182static inline unsigned int mon_get_timestamp(void)
183{
184 struct timespec64 now;
185 unsigned int stamp;
186
187 ktime_get_ts64(ts: &now);
188 stamp = now.tv_sec & 0xFFF; /* 2^32 = 4294967296. Limit to 4096s. */
189 stamp = stamp * USEC_PER_SEC + now.tv_nsec / NSEC_PER_USEC;
190 return stamp;
191}
192
193static void mon_text_event(struct mon_reader_text *rp, struct urb *urb,
194 char ev_type, int status)
195{
196 struct mon_event_text *ep;
197 unsigned int stamp;
198 struct usb_iso_packet_descriptor *fp;
199 struct mon_iso_desc *dp;
200 int i, ndesc;
201
202 stamp = mon_get_timestamp();
203
204 if (rp->nevents >= EVENT_MAX ||
205 (ep = kmem_cache_alloc(rp->e_slab, GFP_ATOMIC)) == NULL) {
206 rp->r.m_bus->cnt_text_lost++;
207 return;
208 }
209
210 ep->type = ev_type;
211 ep->id = (unsigned long) urb;
212 ep->busnum = urb->dev->bus->busnum;
213 ep->devnum = urb->dev->devnum;
214 ep->epnum = usb_endpoint_num(epd: &urb->ep->desc);
215 ep->xfertype = usb_endpoint_type(epd: &urb->ep->desc);
216 ep->is_in = usb_urb_dir_in(urb);
217 ep->tstamp = stamp;
218 ep->length = (ev_type == 'S') ?
219 urb->transfer_buffer_length : urb->actual_length;
220 /* Collecting status makes debugging sense for submits, too */
221 ep->status = status;
222
223 if (ep->xfertype == USB_ENDPOINT_XFER_INT) {
224 ep->interval = urb->interval;
225 } else if (ep->xfertype == USB_ENDPOINT_XFER_ISOC) {
226 ep->interval = urb->interval;
227 ep->start_frame = urb->start_frame;
228 ep->error_count = urb->error_count;
229 }
230 ep->numdesc = urb->number_of_packets;
231 if (ep->xfertype == USB_ENDPOINT_XFER_ISOC &&
232 urb->number_of_packets > 0) {
233 if ((ndesc = urb->number_of_packets) > ISODESC_MAX)
234 ndesc = ISODESC_MAX;
235 fp = urb->iso_frame_desc;
236 dp = ep->isodesc;
237 for (i = 0; i < ndesc; i++) {
238 dp->status = fp->status;
239 dp->offset = fp->offset;
240 dp->length = (ev_type == 'S') ?
241 fp->length : fp->actual_length;
242 fp++;
243 dp++;
244 }
245 /* Wasteful, but simple to understand: ISO 'C' is sparse. */
246 if (ev_type == 'C')
247 ep->length = urb->transfer_buffer_length;
248 }
249
250 ep->setup_flag = mon_text_get_setup(ep, urb, ev_type, mbus: rp->r.m_bus);
251 ep->data_flag = mon_text_get_data(ep, urb, len: ep->length, ev_type,
252 mbus: rp->r.m_bus);
253
254 rp->nevents++;
255 list_add_tail(new: &ep->e_link, head: &rp->e_list);
256 wake_up(&rp->wait);
257}
258
259static void mon_text_submit(void *data, struct urb *urb)
260{
261 struct mon_reader_text *rp = data;
262 mon_text_event(rp, urb, ev_type: 'S', status: -EINPROGRESS);
263}
264
265static void mon_text_complete(void *data, struct urb *urb, int status)
266{
267 struct mon_reader_text *rp = data;
268 mon_text_event(rp, urb, ev_type: 'C', status);
269}
270
271static void mon_text_error(void *data, struct urb *urb, int error)
272{
273 struct mon_reader_text *rp = data;
274 struct mon_event_text *ep;
275
276 if (rp->nevents >= EVENT_MAX ||
277 (ep = kmem_cache_alloc(rp->e_slab, GFP_ATOMIC)) == NULL) {
278 rp->r.m_bus->cnt_text_lost++;
279 return;
280 }
281
282 ep->type = 'E';
283 ep->id = (unsigned long) urb;
284 ep->busnum = urb->dev->bus->busnum;
285 ep->devnum = urb->dev->devnum;
286 ep->epnum = usb_endpoint_num(epd: &urb->ep->desc);
287 ep->xfertype = usb_endpoint_type(epd: &urb->ep->desc);
288 ep->is_in = usb_urb_dir_in(urb);
289 ep->tstamp = mon_get_timestamp();
290 ep->length = 0;
291 ep->status = error;
292
293 ep->setup_flag = '-';
294 ep->data_flag = 'E';
295
296 rp->nevents++;
297 list_add_tail(new: &ep->e_link, head: &rp->e_list);
298 wake_up(&rp->wait);
299}
300
301/*
302 * Fetch next event from the circular buffer.
303 */
304static struct mon_event_text *mon_text_fetch(struct mon_reader_text *rp,
305 struct mon_bus *mbus)
306{
307 struct list_head *p;
308 unsigned long flags;
309
310 spin_lock_irqsave(&mbus->lock, flags);
311 if (list_empty(head: &rp->e_list)) {
312 spin_unlock_irqrestore(lock: &mbus->lock, flags);
313 return NULL;
314 }
315 p = rp->e_list.next;
316 list_del(entry: p);
317 --rp->nevents;
318 spin_unlock_irqrestore(lock: &mbus->lock, flags);
319 return list_entry(p, struct mon_event_text, e_link);
320}
321
322/*
323 */
324static int mon_text_open(struct inode *inode, struct file *file)
325{
326 struct mon_bus *mbus;
327 struct mon_reader_text *rp;
328 int rc;
329
330 mutex_lock(lock: &mon_lock);
331 mbus = inode->i_private;
332
333 rp = kzalloc(sizeof(struct mon_reader_text), GFP_KERNEL);
334 if (rp == NULL) {
335 rc = -ENOMEM;
336 goto err_alloc;
337 }
338 INIT_LIST_HEAD(list: &rp->e_list);
339 init_waitqueue_head(&rp->wait);
340 mutex_init(&rp->printf_lock);
341
342 rp->printf_size = PRINTF_DFL;
343 rp->printf_buf = kmalloc(rp->printf_size, GFP_KERNEL);
344 if (rp->printf_buf == NULL) {
345 rc = -ENOMEM;
346 goto err_alloc_pr;
347 }
348
349 rp->r.m_bus = mbus;
350 rp->r.r_data = rp;
351 rp->r.rnf_submit = mon_text_submit;
352 rp->r.rnf_error = mon_text_error;
353 rp->r.rnf_complete = mon_text_complete;
354
355 scnprintf(buf: rp->slab_name, SLAB_NAME_SZ, fmt: "mon_text_%p", rp);
356 rp->e_slab = kmem_cache_create(rp->slab_name,
357 sizeof(struct mon_event_text), sizeof(long), 0,
358 mon_text_ctor);
359 if (rp->e_slab == NULL) {
360 rc = -ENOMEM;
361 goto err_slab;
362 }
363
364 mon_reader_add(mbus, r: &rp->r);
365
366 file->private_data = rp;
367 mutex_unlock(lock: &mon_lock);
368 return 0;
369
370// err_busy:
371// kmem_cache_destroy(rp->e_slab);
372err_slab:
373 kfree(objp: rp->printf_buf);
374err_alloc_pr:
375 kfree(objp: rp);
376err_alloc:
377 mutex_unlock(lock: &mon_lock);
378 return rc;
379}
380
381static ssize_t mon_text_copy_to_user(struct mon_reader_text *rp,
382 char __user * const buf, const size_t nbytes)
383{
384 const size_t togo = min(nbytes, rp->printf_togo);
385
386 if (copy_to_user(to: buf, from: &rp->printf_buf[rp->printf_offset], n: togo))
387 return -EFAULT;
388 rp->printf_togo -= togo;
389 rp->printf_offset += togo;
390 return togo;
391}
392
393/* ppos is not advanced since the llseek operation is not permitted. */
394static ssize_t mon_text_read_t(struct file *file, char __user *buf,
395 size_t nbytes, loff_t *ppos)
396{
397 struct mon_reader_text *rp = file->private_data;
398 struct mon_event_text *ep;
399 struct mon_text_ptr ptr;
400 ssize_t ret;
401
402 mutex_lock(lock: &rp->printf_lock);
403
404 if (rp->printf_togo == 0) {
405
406 ep = mon_text_read_wait(rp, file);
407 if (IS_ERR(ptr: ep)) {
408 mutex_unlock(lock: &rp->printf_lock);
409 return PTR_ERR(ptr: ep);
410 }
411 ptr.cnt = 0;
412 ptr.pbuf = rp->printf_buf;
413 ptr.limit = rp->printf_size;
414
415 mon_text_read_head_t(rp, p: &ptr, ep);
416 mon_text_read_statset(rp, p: &ptr, ep);
417 ptr.cnt += scnprintf(buf: ptr.pbuf + ptr.cnt, size: ptr.limit - ptr.cnt,
418 fmt: " %d", ep->length);
419 mon_text_read_data(rp, p: &ptr, ep);
420
421 rp->printf_togo = ptr.cnt;
422 rp->printf_offset = 0;
423
424 kmem_cache_free(s: rp->e_slab, objp: ep);
425 }
426
427 ret = mon_text_copy_to_user(rp, buf, nbytes);
428 mutex_unlock(lock: &rp->printf_lock);
429 return ret;
430}
431
432/* ppos is not advanced since the llseek operation is not permitted. */
433static ssize_t mon_text_read_u(struct file *file, char __user *buf,
434 size_t nbytes, loff_t *ppos)
435{
436 struct mon_reader_text *rp = file->private_data;
437 struct mon_event_text *ep;
438 struct mon_text_ptr ptr;
439 ssize_t ret;
440
441 mutex_lock(lock: &rp->printf_lock);
442
443 if (rp->printf_togo == 0) {
444
445 ep = mon_text_read_wait(rp, file);
446 if (IS_ERR(ptr: ep)) {
447 mutex_unlock(lock: &rp->printf_lock);
448 return PTR_ERR(ptr: ep);
449 }
450 ptr.cnt = 0;
451 ptr.pbuf = rp->printf_buf;
452 ptr.limit = rp->printf_size;
453
454 mon_text_read_head_u(rp, p: &ptr, ep);
455 if (ep->type == 'E') {
456 mon_text_read_statset(rp, p: &ptr, ep);
457 } else if (ep->xfertype == USB_ENDPOINT_XFER_ISOC) {
458 mon_text_read_isostat(rp, p: &ptr, ep);
459 mon_text_read_isodesc(rp, p: &ptr, ep);
460 } else if (ep->xfertype == USB_ENDPOINT_XFER_INT) {
461 mon_text_read_intstat(rp, p: &ptr, ep);
462 } else {
463 mon_text_read_statset(rp, p: &ptr, ep);
464 }
465 ptr.cnt += scnprintf(buf: ptr.pbuf + ptr.cnt, size: ptr.limit - ptr.cnt,
466 fmt: " %d", ep->length);
467 mon_text_read_data(rp, p: &ptr, ep);
468
469 rp->printf_togo = ptr.cnt;
470 rp->printf_offset = 0;
471
472 kmem_cache_free(s: rp->e_slab, objp: ep);
473 }
474
475 ret = mon_text_copy_to_user(rp, buf, nbytes);
476 mutex_unlock(lock: &rp->printf_lock);
477 return ret;
478}
479
480static struct mon_event_text *mon_text_read_wait(struct mon_reader_text *rp,
481 struct file *file)
482{
483 struct mon_bus *mbus = rp->r.m_bus;
484 DECLARE_WAITQUEUE(waita, current);
485 struct mon_event_text *ep;
486
487 add_wait_queue(wq_head: &rp->wait, wq_entry: &waita);
488 set_current_state(TASK_INTERRUPTIBLE);
489 while ((ep = mon_text_fetch(rp, mbus)) == NULL) {
490 if (file->f_flags & O_NONBLOCK) {
491 set_current_state(TASK_RUNNING);
492 remove_wait_queue(wq_head: &rp->wait, wq_entry: &waita);
493 return ERR_PTR(error: -EWOULDBLOCK);
494 }
495 /*
496 * We do not count nwaiters, because ->release is supposed
497 * to be called when all openers are gone only.
498 */
499 schedule();
500 if (signal_pending(current)) {
501 remove_wait_queue(wq_head: &rp->wait, wq_entry: &waita);
502 return ERR_PTR(error: -EINTR);
503 }
504 set_current_state(TASK_INTERRUPTIBLE);
505 }
506 set_current_state(TASK_RUNNING);
507 remove_wait_queue(wq_head: &rp->wait, wq_entry: &waita);
508 return ep;
509}
510
511static void mon_text_read_head_t(struct mon_reader_text *rp,
512 struct mon_text_ptr *p, const struct mon_event_text *ep)
513{
514 char udir, utype;
515
516 udir = (ep->is_in ? 'i' : 'o');
517 switch (ep->xfertype) {
518 case USB_ENDPOINT_XFER_ISOC: utype = 'Z'; break;
519 case USB_ENDPOINT_XFER_INT: utype = 'I'; break;
520 case USB_ENDPOINT_XFER_CONTROL: utype = 'C'; break;
521 default: /* PIPE_BULK */ utype = 'B';
522 }
523 p->cnt += scnprintf(buf: p->pbuf + p->cnt, size: p->limit - p->cnt,
524 fmt: "%lx %u %c %c%c:%03u:%02u",
525 ep->id, ep->tstamp, ep->type,
526 utype, udir, ep->devnum, ep->epnum);
527}
528
529static void mon_text_read_head_u(struct mon_reader_text *rp,
530 struct mon_text_ptr *p, const struct mon_event_text *ep)
531{
532 char udir, utype;
533
534 udir = (ep->is_in ? 'i' : 'o');
535 switch (ep->xfertype) {
536 case USB_ENDPOINT_XFER_ISOC: utype = 'Z'; break;
537 case USB_ENDPOINT_XFER_INT: utype = 'I'; break;
538 case USB_ENDPOINT_XFER_CONTROL: utype = 'C'; break;
539 default: /* PIPE_BULK */ utype = 'B';
540 }
541 p->cnt += scnprintf(buf: p->pbuf + p->cnt, size: p->limit - p->cnt,
542 fmt: "%lx %u %c %c%c:%d:%03u:%u",
543 ep->id, ep->tstamp, ep->type,
544 utype, udir, ep->busnum, ep->devnum, ep->epnum);
545}
546
547static void mon_text_read_statset(struct mon_reader_text *rp,
548 struct mon_text_ptr *p, const struct mon_event_text *ep)
549{
550
551 if (ep->setup_flag == 0) { /* Setup packet is present and captured */
552 p->cnt += scnprintf(buf: p->pbuf + p->cnt, size: p->limit - p->cnt,
553 fmt: " s %02x %02x %04x %04x %04x",
554 ep->setup[0],
555 ep->setup[1],
556 (ep->setup[3] << 8) | ep->setup[2],
557 (ep->setup[5] << 8) | ep->setup[4],
558 (ep->setup[7] << 8) | ep->setup[6]);
559 } else if (ep->setup_flag != '-') { /* Unable to capture setup packet */
560 p->cnt += scnprintf(buf: p->pbuf + p->cnt, size: p->limit - p->cnt,
561 fmt: " %c __ __ ____ ____ ____", ep->setup_flag);
562 } else { /* No setup for this kind of URB */
563 p->cnt += scnprintf(buf: p->pbuf + p->cnt, size: p->limit - p->cnt,
564 fmt: " %d", ep->status);
565 }
566}
567
568static void mon_text_read_intstat(struct mon_reader_text *rp,
569 struct mon_text_ptr *p, const struct mon_event_text *ep)
570{
571 p->cnt += scnprintf(buf: p->pbuf + p->cnt, size: p->limit - p->cnt,
572 fmt: " %d:%d", ep->status, ep->interval);
573}
574
575static void mon_text_read_isostat(struct mon_reader_text *rp,
576 struct mon_text_ptr *p, const struct mon_event_text *ep)
577{
578 if (ep->type == 'S') {
579 p->cnt += scnprintf(buf: p->pbuf + p->cnt, size: p->limit - p->cnt,
580 fmt: " %d:%d:%d", ep->status, ep->interval, ep->start_frame);
581 } else {
582 p->cnt += scnprintf(buf: p->pbuf + p->cnt, size: p->limit - p->cnt,
583 fmt: " %d:%d:%d:%d",
584 ep->status, ep->interval, ep->start_frame, ep->error_count);
585 }
586}
587
588static void mon_text_read_isodesc(struct mon_reader_text *rp,
589 struct mon_text_ptr *p, const struct mon_event_text *ep)
590{
591 int ndesc; /* Display this many */
592 int i;
593 const struct mon_iso_desc *dp;
594
595 p->cnt += scnprintf(buf: p->pbuf + p->cnt, size: p->limit - p->cnt,
596 fmt: " %d", ep->numdesc);
597 ndesc = ep->numdesc;
598 if (ndesc > ISODESC_MAX)
599 ndesc = ISODESC_MAX;
600 if (ndesc < 0)
601 ndesc = 0;
602 dp = ep->isodesc;
603 for (i = 0; i < ndesc; i++) {
604 p->cnt += scnprintf(buf: p->pbuf + p->cnt, size: p->limit - p->cnt,
605 fmt: " %d:%u:%u", dp->status, dp->offset, dp->length);
606 dp++;
607 }
608}
609
610static void mon_text_read_data(struct mon_reader_text *rp,
611 struct mon_text_ptr *p, const struct mon_event_text *ep)
612{
613 int data_len, i;
614
615 if ((data_len = ep->length) > 0) {
616 if (ep->data_flag == 0) {
617 p->cnt += scnprintf(buf: p->pbuf + p->cnt, size: p->limit - p->cnt,
618 fmt: " =");
619 if (data_len >= DATA_MAX)
620 data_len = DATA_MAX;
621 for (i = 0; i < data_len; i++) {
622 if (i % 4 == 0) {
623 p->cnt += scnprintf(buf: p->pbuf + p->cnt,
624 size: p->limit - p->cnt,
625 fmt: " ");
626 }
627 p->cnt += scnprintf(buf: p->pbuf + p->cnt,
628 size: p->limit - p->cnt,
629 fmt: "%02x", ep->data[i]);
630 }
631 p->cnt += scnprintf(buf: p->pbuf + p->cnt, size: p->limit - p->cnt,
632 fmt: "\n");
633 } else {
634 p->cnt += scnprintf(buf: p->pbuf + p->cnt, size: p->limit - p->cnt,
635 fmt: " %c\n", ep->data_flag);
636 }
637 } else {
638 p->cnt += scnprintf(buf: p->pbuf + p->cnt, size: p->limit - p->cnt, fmt: "\n");
639 }
640}
641
642static int mon_text_release(struct inode *inode, struct file *file)
643{
644 struct mon_reader_text *rp = file->private_data;
645 struct mon_bus *mbus;
646 /* unsigned long flags; */
647 struct list_head *p;
648 struct mon_event_text *ep;
649
650 mutex_lock(lock: &mon_lock);
651 mbus = inode->i_private;
652
653 if (mbus->nreaders <= 0) {
654 printk(KERN_ERR TAG ": consistency error on close\n");
655 mutex_unlock(lock: &mon_lock);
656 return 0;
657 }
658 mon_reader_del(mbus, r: &rp->r);
659
660 /*
661 * In theory, e_list is protected by mbus->lock. However,
662 * after mon_reader_del has finished, the following is the case:
663 * - we are not on reader list anymore, so new events won't be added;
664 * - whole mbus may be dropped if it was orphaned.
665 * So, we better not touch mbus.
666 */
667 /* spin_lock_irqsave(&mbus->lock, flags); */
668 while (!list_empty(head: &rp->e_list)) {
669 p = rp->e_list.next;
670 ep = list_entry(p, struct mon_event_text, e_link);
671 list_del(entry: p);
672 --rp->nevents;
673 kmem_cache_free(s: rp->e_slab, objp: ep);
674 }
675 /* spin_unlock_irqrestore(&mbus->lock, flags); */
676
677 kmem_cache_destroy(s: rp->e_slab);
678 kfree(objp: rp->printf_buf);
679 kfree(objp: rp);
680
681 mutex_unlock(lock: &mon_lock);
682 return 0;
683}
684
685static const struct file_operations mon_fops_text_t = {
686 .owner = THIS_MODULE,
687 .open = mon_text_open,
688 .read = mon_text_read_t,
689 .release = mon_text_release,
690};
691
692static const struct file_operations mon_fops_text_u = {
693 .owner = THIS_MODULE,
694 .open = mon_text_open,
695 .read = mon_text_read_u,
696 .release = mon_text_release,
697};
698
699int mon_text_add(struct mon_bus *mbus, const struct usb_bus *ubus)
700{
701 enum { NAMESZ = 12 };
702 char name[NAMESZ];
703 int busnum = ubus? ubus->busnum: 0;
704
705 if (mon_dir == NULL)
706 return 0;
707
708 if (ubus != NULL) {
709 scnprintf(buf: name, size: NAMESZ, fmt: "%dt", busnum);
710 mbus->dent_t = debugfs_create_file(name, 0600, mon_dir, mbus,
711 &mon_fops_text_t);
712 }
713
714 scnprintf(buf: name, size: NAMESZ, fmt: "%du", busnum);
715 mbus->dent_u = debugfs_create_file(name, 0600, mon_dir, mbus,
716 &mon_fops_text_u);
717
718 scnprintf(buf: name, size: NAMESZ, fmt: "%ds", busnum);
719 mbus->dent_s = debugfs_create_file(name, 0600, mon_dir, mbus,
720 &mon_fops_stat);
721
722 return 1;
723}
724
725void mon_text_del(struct mon_bus *mbus)
726{
727 debugfs_remove(dentry: mbus->dent_u);
728 debugfs_remove(dentry: mbus->dent_t);
729 debugfs_remove(dentry: mbus->dent_s);
730}
731
732/*
733 * Slab interface: constructor.
734 */
735static void mon_text_ctor(void *mem)
736{
737 /*
738 * Nothing to initialize. No, really!
739 * So, we fill it with garbage to emulate a reused object.
740 */
741 memset(s: mem, c: 0xe5, n: sizeof(struct mon_event_text));
742}
743
744int __init mon_text_init(void)
745{
746 mon_dir = debugfs_create_dir(name: "usbmon", parent: usb_debug_root);
747 return 0;
748}
749
750void mon_text_exit(void)
751{
752 debugfs_remove(dentry: mon_dir);
753}
754