2 * The USB Monitor, inspired by Dave Harding's USBMon.
4 * This is a text format reader.
7 #include <linux/kernel.h>
8 #include <linux/list.h>
10 #include <linux/slab.h>
11 #include <linux/time.h>
12 #include <linux/export.h>
13 #include <linux/mutex.h>
14 #include <linux/debugfs.h>
15 #include <linux/scatterlist.h>
16 #include <asm/uaccess.h>
21 * No, we do not want arbitrarily long data strings.
22 * Use the binary interface if you want to capture bulk data!
27 * Defined by USB 2.0 clause 9.3, table 9.2.
32 * This limit exists to prevent OOMs when the user process stops reading.
33 * If usbmon were available to unprivileged processes, it might be open
34 * to a local DoS. But we have to keep to root in order to prevent
35 * password sniffing from HID devices.
37 #define EVENT_MAX (4*PAGE_SIZE / sizeof(struct mon_event_text))
40 * Potentially unlimited number; we limit it for similar allocations.
41 * The usbfs limits this to 128, but we're not quite as generous.
45 #define PRINTF_DFL 250 /* with 5 ISOs segs */
50 unsigned int length; /* Unsigned here, signed in URB. Historic. */
53 struct mon_event_text {
54 struct list_head e_link;
55 int type; /* submit, complete, etc. */
56 unsigned long id; /* From pointer, most of the time */
63 int length; /* Depends on type: xfer length or act length */
70 int numdesc; /* Full number */
71 struct mon_iso_desc isodesc[ISODESC_MAX];
72 unsigned char setup[SETUP_MAX];
73 unsigned char data[DATA_MAX];
76 #define SLAB_NAME_SZ 30
77 struct mon_reader_text {
78 struct kmem_cache *e_slab;
80 struct list_head e_list;
81 struct mon_reader r; /* In C, parent class can be placed anywhere */
83 wait_queue_head_t wait;
86 struct mutex printf_lock;
88 char slab_name[SLAB_NAME_SZ];
91 static struct dentry *mon_dir; /* Usually /sys/kernel/debug/usbmon */
93 static void mon_text_ctor(void *);
100 static struct mon_event_text *
101 mon_text_read_wait(struct mon_reader_text *rp, struct file *file);
102 static void mon_text_read_head_t(struct mon_reader_text *rp,
103 struct mon_text_ptr *p, const struct mon_event_text *ep);
104 static void mon_text_read_head_u(struct mon_reader_text *rp,
105 struct mon_text_ptr *p, const struct mon_event_text *ep);
106 static void mon_text_read_statset(struct mon_reader_text *rp,
107 struct mon_text_ptr *p, const struct mon_event_text *ep);
108 static void mon_text_read_intstat(struct mon_reader_text *rp,
109 struct mon_text_ptr *p, const struct mon_event_text *ep);
110 static void mon_text_read_isostat(struct mon_reader_text *rp,
111 struct mon_text_ptr *p, const struct mon_event_text *ep);
112 static void mon_text_read_isodesc(struct mon_reader_text *rp,
113 struct mon_text_ptr *p, const struct mon_event_text *ep);
114 static void mon_text_read_data(struct mon_reader_text *rp,
115 struct mon_text_ptr *p, const struct mon_event_text *ep);
121 * May be called from an interrupt.
123 * This is called with the whole mon_bus locked, so no additional lock.
126 static inline char mon_text_get_setup(struct mon_event_text *ep,
127 struct urb *urb, char ev_type, struct mon_bus *mbus)
130 if (ep->xfertype != USB_ENDPOINT_XFER_CONTROL || ev_type != 'S')
133 if (urb->setup_packet == NULL)
134 return 'Z'; /* '0' would be not as pretty. */
136 memcpy(ep->setup, urb->setup_packet, SETUP_MAX);
140 static inline char mon_text_get_data(struct mon_event_text *ep, struct urb *urb,
141 int len, char ev_type, struct mon_bus *mbus)
158 if (urb->num_sgs == 0) {
159 src = urb->transfer_buffer;
161 return 'Z'; /* '0' would be not as pretty. */
163 struct scatterlist *sg = urb->sg;
165 if (PageHighMem(sg_page(sg)))
168 /* For the text interface we copy only the first sg buffer */
169 len = min_t(int, sg->length, len);
173 memcpy(ep->data, src, len);
177 static inline unsigned int mon_get_timestamp(void)
182 do_gettimeofday(&tval);
183 stamp = tval.tv_sec & 0xFFF; /* 2^32 = 4294967296. Limit to 4096s. */
184 stamp = stamp * 1000000 + tval.tv_usec;
188 static void mon_text_event(struct mon_reader_text *rp, struct urb *urb,
189 char ev_type, int status)
191 struct mon_event_text *ep;
193 struct usb_iso_packet_descriptor *fp;
194 struct mon_iso_desc *dp;
197 stamp = mon_get_timestamp();
199 if (rp->nevents >= EVENT_MAX ||
200 (ep = kmem_cache_alloc(rp->e_slab, GFP_ATOMIC)) == NULL) {
201 rp->r.m_bus->cnt_text_lost++;
206 ep->id = (unsigned long) urb;
207 ep->busnum = urb->dev->bus->busnum;
208 ep->devnum = urb->dev->devnum;
209 ep->epnum = usb_endpoint_num(&urb->ep->desc);
210 ep->xfertype = usb_endpoint_type(&urb->ep->desc);
211 ep->is_in = usb_urb_dir_in(urb);
213 ep->length = (ev_type == 'S') ?
214 urb->transfer_buffer_length : urb->actual_length;
215 /* Collecting status makes debugging sense for submits, too */
218 if (ep->xfertype == USB_ENDPOINT_XFER_INT) {
219 ep->interval = urb->interval;
220 } else if (ep->xfertype == USB_ENDPOINT_XFER_ISOC) {
221 ep->interval = urb->interval;
222 ep->start_frame = urb->start_frame;
223 ep->error_count = urb->error_count;
225 ep->numdesc = urb->number_of_packets;
226 if (ep->xfertype == USB_ENDPOINT_XFER_ISOC &&
227 urb->number_of_packets > 0) {
228 if ((ndesc = urb->number_of_packets) > ISODESC_MAX)
230 fp = urb->iso_frame_desc;
232 for (i = 0; i < ndesc; i++) {
233 dp->status = fp->status;
234 dp->offset = fp->offset;
235 dp->length = (ev_type == 'S') ?
236 fp->length : fp->actual_length;
240 /* Wasteful, but simple to understand: ISO 'C' is sparse. */
242 ep->length = urb->transfer_buffer_length;
245 ep->setup_flag = mon_text_get_setup(ep, urb, ev_type, rp->r.m_bus);
246 ep->data_flag = mon_text_get_data(ep, urb, ep->length, ev_type,
250 list_add_tail(&ep->e_link, &rp->e_list);
254 static void mon_text_submit(void *data, struct urb *urb)
256 struct mon_reader_text *rp = data;
257 mon_text_event(rp, urb, 'S', -EINPROGRESS);
260 static void mon_text_complete(void *data, struct urb *urb, int status)
262 struct mon_reader_text *rp = data;
263 mon_text_event(rp, urb, 'C', status);
266 static void mon_text_error(void *data, struct urb *urb, int error)
268 struct mon_reader_text *rp = data;
269 struct mon_event_text *ep;
271 if (rp->nevents >= EVENT_MAX ||
272 (ep = kmem_cache_alloc(rp->e_slab, GFP_ATOMIC)) == NULL) {
273 rp->r.m_bus->cnt_text_lost++;
278 ep->id = (unsigned long) urb;
279 ep->busnum = urb->dev->bus->busnum;
280 ep->devnum = urb->dev->devnum;
281 ep->epnum = usb_endpoint_num(&urb->ep->desc);
282 ep->xfertype = usb_endpoint_type(&urb->ep->desc);
283 ep->is_in = usb_urb_dir_in(urb);
284 ep->tstamp = mon_get_timestamp();
288 ep->setup_flag = '-';
292 list_add_tail(&ep->e_link, &rp->e_list);
297 * Fetch next event from the circular buffer.
299 static struct mon_event_text *mon_text_fetch(struct mon_reader_text *rp,
300 struct mon_bus *mbus)
305 spin_lock_irqsave(&mbus->lock, flags);
306 if (list_empty(&rp->e_list)) {
307 spin_unlock_irqrestore(&mbus->lock, flags);
313 spin_unlock_irqrestore(&mbus->lock, flags);
314 return list_entry(p, struct mon_event_text, e_link);
319 static int mon_text_open(struct inode *inode, struct file *file)
321 struct mon_bus *mbus;
322 struct mon_reader_text *rp;
325 mutex_lock(&mon_lock);
326 mbus = inode->i_private;
328 rp = kzalloc(sizeof(struct mon_reader_text), GFP_KERNEL);
333 INIT_LIST_HEAD(&rp->e_list);
334 init_waitqueue_head(&rp->wait);
335 mutex_init(&rp->printf_lock);
337 rp->printf_size = PRINTF_DFL;
338 rp->printf_buf = kmalloc(rp->printf_size, GFP_KERNEL);
339 if (rp->printf_buf == NULL) {
346 rp->r.rnf_submit = mon_text_submit;
347 rp->r.rnf_error = mon_text_error;
348 rp->r.rnf_complete = mon_text_complete;
350 snprintf(rp->slab_name, SLAB_NAME_SZ, "mon_text_%p", rp);
351 rp->e_slab = kmem_cache_create(rp->slab_name,
352 sizeof(struct mon_event_text), sizeof(long), 0,
354 if (rp->e_slab == NULL) {
359 mon_reader_add(mbus, &rp->r);
361 file->private_data = rp;
362 mutex_unlock(&mon_lock);
366 // kmem_cache_destroy(rp->e_slab);
368 kfree(rp->printf_buf);
372 mutex_unlock(&mon_lock);
377 * For simplicity, we read one record in one system call and throw out
378 * what does not fit. This means that the following does not work:
379 * dd if=/dbg/usbmon/0t bs=10
380 * Also, we do not allow seeks and do not bother advancing the offset.
382 static ssize_t mon_text_read_t(struct file *file, char __user *buf,
383 size_t nbytes, loff_t *ppos)
385 struct mon_reader_text *rp = file->private_data;
386 struct mon_event_text *ep;
387 struct mon_text_ptr ptr;
389 ep = mon_text_read_wait(rp, file);
392 mutex_lock(&rp->printf_lock);
394 ptr.pbuf = rp->printf_buf;
395 ptr.limit = rp->printf_size;
397 mon_text_read_head_t(rp, &ptr, ep);
398 mon_text_read_statset(rp, &ptr, ep);
399 ptr.cnt += snprintf(ptr.pbuf + ptr.cnt, ptr.limit - ptr.cnt,
401 mon_text_read_data(rp, &ptr, ep);
403 if (copy_to_user(buf, rp->printf_buf, ptr.cnt))
405 mutex_unlock(&rp->printf_lock);
406 kmem_cache_free(rp->e_slab, ep);
410 static ssize_t mon_text_read_u(struct file *file, char __user *buf,
411 size_t nbytes, loff_t *ppos)
413 struct mon_reader_text *rp = file->private_data;
414 struct mon_event_text *ep;
415 struct mon_text_ptr ptr;
417 ep = mon_text_read_wait(rp, file);
420 mutex_lock(&rp->printf_lock);
422 ptr.pbuf = rp->printf_buf;
423 ptr.limit = rp->printf_size;
425 mon_text_read_head_u(rp, &ptr, ep);
426 if (ep->type == 'E') {
427 mon_text_read_statset(rp, &ptr, ep);
428 } else if (ep->xfertype == USB_ENDPOINT_XFER_ISOC) {
429 mon_text_read_isostat(rp, &ptr, ep);
430 mon_text_read_isodesc(rp, &ptr, ep);
431 } else if (ep->xfertype == USB_ENDPOINT_XFER_INT) {
432 mon_text_read_intstat(rp, &ptr, ep);
434 mon_text_read_statset(rp, &ptr, ep);
436 ptr.cnt += snprintf(ptr.pbuf + ptr.cnt, ptr.limit - ptr.cnt,
438 mon_text_read_data(rp, &ptr, ep);
440 if (copy_to_user(buf, rp->printf_buf, ptr.cnt))
442 mutex_unlock(&rp->printf_lock);
443 kmem_cache_free(rp->e_slab, ep);
447 static struct mon_event_text *mon_text_read_wait(struct mon_reader_text *rp,
450 struct mon_bus *mbus = rp->r.m_bus;
451 DECLARE_WAITQUEUE(waita, current);
452 struct mon_event_text *ep;
454 add_wait_queue(&rp->wait, &waita);
455 set_current_state(TASK_INTERRUPTIBLE);
456 while ((ep = mon_text_fetch(rp, mbus)) == NULL) {
457 if (file->f_flags & O_NONBLOCK) {
458 set_current_state(TASK_RUNNING);
459 remove_wait_queue(&rp->wait, &waita);
460 return ERR_PTR(-EWOULDBLOCK);
463 * We do not count nwaiters, because ->release is supposed
464 * to be called when all openers are gone only.
467 if (signal_pending(current)) {
468 remove_wait_queue(&rp->wait, &waita);
469 return ERR_PTR(-EINTR);
471 set_current_state(TASK_INTERRUPTIBLE);
473 set_current_state(TASK_RUNNING);
474 remove_wait_queue(&rp->wait, &waita);
478 static void mon_text_read_head_t(struct mon_reader_text *rp,
479 struct mon_text_ptr *p, const struct mon_event_text *ep)
483 udir = (ep->is_in ? 'i' : 'o');
484 switch (ep->xfertype) {
485 case USB_ENDPOINT_XFER_ISOC: utype = 'Z'; break;
486 case USB_ENDPOINT_XFER_INT: utype = 'I'; break;
487 case USB_ENDPOINT_XFER_CONTROL: utype = 'C'; break;
488 default: /* PIPE_BULK */ utype = 'B';
490 p->cnt += snprintf(p->pbuf + p->cnt, p->limit - p->cnt,
491 "%lx %u %c %c%c:%03u:%02u",
492 ep->id, ep->tstamp, ep->type,
493 utype, udir, ep->devnum, ep->epnum);
496 static void mon_text_read_head_u(struct mon_reader_text *rp,
497 struct mon_text_ptr *p, const struct mon_event_text *ep)
501 udir = (ep->is_in ? 'i' : 'o');
502 switch (ep->xfertype) {
503 case USB_ENDPOINT_XFER_ISOC: utype = 'Z'; break;
504 case USB_ENDPOINT_XFER_INT: utype = 'I'; break;
505 case USB_ENDPOINT_XFER_CONTROL: utype = 'C'; break;
506 default: /* PIPE_BULK */ utype = 'B';
508 p->cnt += snprintf(p->pbuf + p->cnt, p->limit - p->cnt,
509 "%lx %u %c %c%c:%d:%03u:%u",
510 ep->id, ep->tstamp, ep->type,
511 utype, udir, ep->busnum, ep->devnum, ep->epnum);
514 static void mon_text_read_statset(struct mon_reader_text *rp,
515 struct mon_text_ptr *p, const struct mon_event_text *ep)
518 if (ep->setup_flag == 0) { /* Setup packet is present and captured */
519 p->cnt += snprintf(p->pbuf + p->cnt, p->limit - p->cnt,
520 " s %02x %02x %04x %04x %04x",
523 (ep->setup[3] << 8) | ep->setup[2],
524 (ep->setup[5] << 8) | ep->setup[4],
525 (ep->setup[7] << 8) | ep->setup[6]);
526 } else if (ep->setup_flag != '-') { /* Unable to capture setup packet */
527 p->cnt += snprintf(p->pbuf + p->cnt, p->limit - p->cnt,
528 " %c __ __ ____ ____ ____", ep->setup_flag);
529 } else { /* No setup for this kind of URB */
530 p->cnt += snprintf(p->pbuf + p->cnt, p->limit - p->cnt,
535 static void mon_text_read_intstat(struct mon_reader_text *rp,
536 struct mon_text_ptr *p, const struct mon_event_text *ep)
538 p->cnt += snprintf(p->pbuf + p->cnt, p->limit - p->cnt,
539 " %d:%d", ep->status, ep->interval);
542 static void mon_text_read_isostat(struct mon_reader_text *rp,
543 struct mon_text_ptr *p, const struct mon_event_text *ep)
545 if (ep->type == 'S') {
546 p->cnt += snprintf(p->pbuf + p->cnt, p->limit - p->cnt,
547 " %d:%d:%d", ep->status, ep->interval, ep->start_frame);
549 p->cnt += snprintf(p->pbuf + p->cnt, p->limit - p->cnt,
551 ep->status, ep->interval, ep->start_frame, ep->error_count);
555 static void mon_text_read_isodesc(struct mon_reader_text *rp,
556 struct mon_text_ptr *p, const struct mon_event_text *ep)
558 int ndesc; /* Display this many */
560 const struct mon_iso_desc *dp;
562 p->cnt += snprintf(p->pbuf + p->cnt, p->limit - p->cnt,
565 if (ndesc > ISODESC_MAX)
570 for (i = 0; i < ndesc; i++) {
571 p->cnt += snprintf(p->pbuf + p->cnt, p->limit - p->cnt,
572 " %d:%u:%u", dp->status, dp->offset, dp->length);
577 static void mon_text_read_data(struct mon_reader_text *rp,
578 struct mon_text_ptr *p, const struct mon_event_text *ep)
582 if ((data_len = ep->length) > 0) {
583 if (ep->data_flag == 0) {
584 p->cnt += snprintf(p->pbuf + p->cnt, p->limit - p->cnt,
586 if (data_len >= DATA_MAX)
588 for (i = 0; i < data_len; i++) {
590 p->cnt += snprintf(p->pbuf + p->cnt,
594 p->cnt += snprintf(p->pbuf + p->cnt,
596 "%02x", ep->data[i]);
598 p->cnt += snprintf(p->pbuf + p->cnt, p->limit - p->cnt,
601 p->cnt += snprintf(p->pbuf + p->cnt, p->limit - p->cnt,
602 " %c\n", ep->data_flag);
605 p->cnt += snprintf(p->pbuf + p->cnt, p->limit - p->cnt, "\n");
609 static int mon_text_release(struct inode *inode, struct file *file)
611 struct mon_reader_text *rp = file->private_data;
612 struct mon_bus *mbus;
613 /* unsigned long flags; */
615 struct mon_event_text *ep;
617 mutex_lock(&mon_lock);
618 mbus = inode->i_private;
620 if (mbus->nreaders <= 0) {
621 printk(KERN_ERR TAG ": consistency error on close\n");
622 mutex_unlock(&mon_lock);
625 mon_reader_del(mbus, &rp->r);
628 * In theory, e_list is protected by mbus->lock. However,
629 * after mon_reader_del has finished, the following is the case:
630 * - we are not on reader list anymore, so new events won't be added;
631 * - whole mbus may be dropped if it was orphaned.
632 * So, we better not touch mbus.
634 /* spin_lock_irqsave(&mbus->lock, flags); */
635 while (!list_empty(&rp->e_list)) {
637 ep = list_entry(p, struct mon_event_text, e_link);
640 kmem_cache_free(rp->e_slab, ep);
642 /* spin_unlock_irqrestore(&mbus->lock, flags); */
644 kmem_cache_destroy(rp->e_slab);
645 kfree(rp->printf_buf);
648 mutex_unlock(&mon_lock);
652 static const struct file_operations mon_fops_text_t = {
653 .owner = THIS_MODULE,
654 .open = mon_text_open,
656 .read = mon_text_read_t,
657 .release = mon_text_release,
660 static const struct file_operations mon_fops_text_u = {
661 .owner = THIS_MODULE,
662 .open = mon_text_open,
664 .read = mon_text_read_u,
665 .release = mon_text_release,
668 int mon_text_add(struct mon_bus *mbus, const struct usb_bus *ubus)
671 enum { NAMESZ = 10 };
673 int busnum = ubus? ubus->busnum: 0;
680 rc = snprintf(name, NAMESZ, "%dt", busnum);
681 if (rc <= 0 || rc >= NAMESZ)
683 d = debugfs_create_file(name, 0600, mon_dir, mbus,
690 rc = snprintf(name, NAMESZ, "%du", busnum);
691 if (rc <= 0 || rc >= NAMESZ)
693 d = debugfs_create_file(name, 0600, mon_dir, mbus, &mon_fops_text_u);
698 rc = snprintf(name, NAMESZ, "%ds", busnum);
699 if (rc <= 0 || rc >= NAMESZ)
701 d = debugfs_create_file(name, 0600, mon_dir, mbus, &mon_fops_stat);
710 debugfs_remove(mbus->dent_u);
715 debugfs_remove(mbus->dent_t);
723 void mon_text_del(struct mon_bus *mbus)
725 debugfs_remove(mbus->dent_u);
726 if (mbus->dent_t != NULL)
727 debugfs_remove(mbus->dent_t);
728 debugfs_remove(mbus->dent_s);
732 * Slab interface: constructor.
734 static void mon_text_ctor(void *mem)
737 * Nothing to initialize. No, really!
738 * So, we fill it with garbage to emulate a reused object.
740 memset(mem, 0xe5, sizeof(struct mon_event_text));
743 int __init mon_text_init(void)
745 struct dentry *mondir;
747 mondir = debugfs_create_dir("usbmon", usb_debug_root);
748 if (IS_ERR(mondir)) {
749 /* debugfs not available, but we can use usbmon without it */
752 if (mondir == NULL) {
753 printk(KERN_NOTICE TAG ": unable to create usbmon directory\n");
760 void mon_text_exit(void)
762 debugfs_remove(mon_dir);