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/time.h>
11 #include <linux/mutex.h>
12 #include <asm/uaccess.h>
17 * No, we do not want arbitrarily long data strings.
18 * Use the binary interface if you want to capture bulk data!
23 * Defined by USB 2.0 clause 9.3, table 9.2.
28 * This limit exists to prevent OOMs when the user process stops reading.
32 #define PRINTF_DFL 130
34 struct mon_event_text {
35 struct list_head e_link;
36 int type; /* submit, complete, etc. */
37 unsigned int pipe; /* Pipe */
38 unsigned long id; /* From pointer, most of the time */
40 int length; /* Depends on type: xfer length or act length */
44 unsigned char setup[SETUP_MAX];
45 unsigned char data[DATA_MAX];
48 #define SLAB_NAME_SZ 30
49 struct mon_reader_text {
52 struct list_head e_list;
53 struct mon_reader r; /* In C, parent class can be placed anywhere */
55 wait_queue_head_t wait;
58 struct mutex printf_lock;
60 char slab_name[SLAB_NAME_SZ];
63 static void mon_text_ctor(void *, kmem_cache_t *, unsigned long);
64 static void mon_text_dtor(void *, kmem_cache_t *, unsigned long);
70 * May be called from an interrupt.
72 * This is called with the whole mon_bus locked, so no additional lock.
75 static inline char mon_text_get_setup(struct mon_event_text *ep,
76 struct urb *urb, char ev_type)
79 if (!usb_pipecontrol(urb->pipe) || ev_type != 'S')
82 if (urb->transfer_flags & URB_NO_SETUP_DMA_MAP)
83 return mon_dmapeek(ep->setup, urb->setup_dma, SETUP_MAX);
84 if (urb->setup_packet == NULL)
85 return 'Z'; /* '0' would be not as pretty. */
87 memcpy(ep->setup, urb->setup_packet, SETUP_MAX);
91 static inline char mon_text_get_data(struct mon_event_text *ep, struct urb *urb,
92 int len, char ev_type)
101 if (usb_pipein(pipe)) {
110 * The check to see if it's safe to poke at data has an enormous
111 * number of corner cases, but it seems that the following is
114 * We do not even try to look transfer_buffer, because it can
115 * contain non-NULL garbage in case the upper level promised to
116 * set DMA for the HCD.
118 if (urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)
119 return mon_dmapeek(ep->data, urb->transfer_dma, len);
121 if (urb->transfer_buffer == NULL)
122 return 'Z'; /* '0' would be not as pretty. */
124 memcpy(ep->data, urb->transfer_buffer, len);
128 static inline unsigned int mon_get_timestamp(void)
133 do_gettimeofday(&tval);
134 stamp = tval.tv_sec & 0xFFFF; /* 2^32 = 4294967296. Limit to 4096s. */
135 stamp = stamp * 1000000 + tval.tv_usec;
139 static void mon_text_event(struct mon_reader_text *rp, struct urb *urb,
142 struct mon_event_text *ep;
145 stamp = mon_get_timestamp();
147 if (rp->nevents >= EVENT_MAX ||
148 (ep = kmem_cache_alloc(rp->e_slab, SLAB_ATOMIC)) == NULL) {
149 rp->r.m_bus->cnt_text_lost++;
154 ep->pipe = urb->pipe;
155 ep->id = (unsigned long) urb;
157 ep->length = (ev_type == 'S') ?
158 urb->transfer_buffer_length : urb->actual_length;
159 /* Collecting status makes debugging sense for submits, too */
160 ep->status = urb->status;
162 ep->setup_flag = mon_text_get_setup(ep, urb, ev_type);
163 ep->data_flag = mon_text_get_data(ep, urb, ep->length, ev_type);
166 list_add_tail(&ep->e_link, &rp->e_list);
170 static void mon_text_submit(void *data, struct urb *urb)
172 struct mon_reader_text *rp = data;
173 mon_text_event(rp, urb, 'S');
176 static void mon_text_complete(void *data, struct urb *urb)
178 struct mon_reader_text *rp = data;
179 mon_text_event(rp, urb, 'C');
183 * Fetch next event from the circular buffer.
185 static struct mon_event_text *mon_text_fetch(struct mon_reader_text *rp,
186 struct mon_bus *mbus)
191 spin_lock_irqsave(&mbus->lock, flags);
192 if (list_empty(&rp->e_list)) {
193 spin_unlock_irqrestore(&mbus->lock, flags);
199 spin_unlock_irqrestore(&mbus->lock, flags);
200 return list_entry(p, struct mon_event_text, e_link);
205 static int mon_text_open(struct inode *inode, struct file *file)
207 struct mon_bus *mbus;
208 struct usb_bus *ubus;
209 struct mon_reader_text *rp;
212 mutex_lock(&mon_lock);
213 mbus = inode->u.generic_ip;
216 rp = kmalloc(sizeof(struct mon_reader_text), GFP_KERNEL);
221 memset(rp, 0, sizeof(struct mon_reader_text));
222 INIT_LIST_HEAD(&rp->e_list);
223 init_waitqueue_head(&rp->wait);
224 mutex_init(&rp->printf_lock);
226 rp->printf_size = PRINTF_DFL;
227 rp->printf_buf = kmalloc(rp->printf_size, GFP_KERNEL);
228 if (rp->printf_buf == NULL) {
235 rp->r.rnf_submit = mon_text_submit;
236 rp->r.rnf_complete = mon_text_complete;
238 snprintf(rp->slab_name, SLAB_NAME_SZ, "mon%dt_%lx", ubus->busnum,
240 rp->e_slab = kmem_cache_create(rp->slab_name,
241 sizeof(struct mon_event_text), sizeof(long), 0,
242 mon_text_ctor, mon_text_dtor);
243 if (rp->e_slab == NULL) {
248 mon_reader_add(mbus, &rp->r);
250 file->private_data = rp;
251 mutex_unlock(&mon_lock);
255 // kmem_cache_destroy(rp->e_slab);
257 kfree(rp->printf_buf);
261 mutex_unlock(&mon_lock);
266 * For simplicity, we read one record in one system call and throw out
267 * what does not fit. This means that the following does not work:
268 * dd if=/dbg/usbmon/0t bs=10
269 * Also, we do not allow seeks and do not bother advancing the offset.
271 static ssize_t mon_text_read(struct file *file, char __user *buf,
272 size_t nbytes, loff_t *ppos)
274 struct mon_reader_text *rp = file->private_data;
275 struct mon_bus *mbus = rp->r.m_bus;
276 DECLARE_WAITQUEUE(waita, current);
277 struct mon_event_text *ep;
283 add_wait_queue(&rp->wait, &waita);
284 set_current_state(TASK_INTERRUPTIBLE);
285 while ((ep = mon_text_fetch(rp, mbus)) == NULL) {
286 if (file->f_flags & O_NONBLOCK) {
287 set_current_state(TASK_RUNNING);
288 remove_wait_queue(&rp->wait, &waita);
289 return -EWOULDBLOCK; /* Same as EAGAIN in Linux */
292 * We do not count nwaiters, because ->release is supposed
293 * to be called when all openers are gone only.
296 if (signal_pending(current)) {
297 remove_wait_queue(&rp->wait, &waita);
300 set_current_state(TASK_INTERRUPTIBLE);
302 set_current_state(TASK_RUNNING);
303 remove_wait_queue(&rp->wait, &waita);
305 mutex_lock(&rp->printf_lock);
307 pbuf = rp->printf_buf;
308 limit = rp->printf_size;
310 udir = usb_pipein(ep->pipe) ? 'i' : 'o';
311 switch (usb_pipetype(ep->pipe)) {
312 case PIPE_ISOCHRONOUS: utype = 'Z'; break;
313 case PIPE_INTERRUPT: utype = 'I'; break;
314 case PIPE_CONTROL: utype = 'C'; break;
315 default: /* PIPE_BULK */ utype = 'B';
317 cnt += snprintf(pbuf + cnt, limit - cnt,
318 "%lx %u %c %c%c:%03u:%02u",
319 ep->id, ep->tstamp, ep->type,
320 utype, udir, usb_pipedevice(ep->pipe), usb_pipeendpoint(ep->pipe));
322 if (ep->setup_flag == 0) { /* Setup packet is present and captured */
323 cnt += snprintf(pbuf + cnt, limit - cnt,
324 " s %02x %02x %04x %04x %04x",
327 (ep->setup[3] << 8) | ep->setup[2],
328 (ep->setup[5] << 8) | ep->setup[4],
329 (ep->setup[7] << 8) | ep->setup[6]);
330 } else if (ep->setup_flag != '-') { /* Unable to capture setup packet */
331 cnt += snprintf(pbuf + cnt, limit - cnt,
332 " %c __ __ ____ ____ ____", ep->setup_flag);
333 } else { /* No setup for this kind of URB */
334 cnt += snprintf(pbuf + cnt, limit - cnt, " %d", ep->status);
336 cnt += snprintf(pbuf + cnt, limit - cnt, " %d", ep->length);
338 if ((data_len = ep->length) > 0) {
339 if (ep->data_flag == 0) {
340 cnt += snprintf(pbuf + cnt, limit - cnt, " =");
341 if (data_len >= DATA_MAX)
343 for (i = 0; i < data_len; i++) {
345 cnt += snprintf(pbuf + cnt, limit - cnt,
348 cnt += snprintf(pbuf + cnt, limit - cnt,
349 "%02x", ep->data[i]);
351 cnt += snprintf(pbuf + cnt, limit - cnt, "\n");
353 cnt += snprintf(pbuf + cnt, limit - cnt,
354 " %c\n", ep->data_flag);
357 cnt += snprintf(pbuf + cnt, limit - cnt, "\n");
360 if (copy_to_user(buf, rp->printf_buf, cnt))
362 mutex_unlock(&rp->printf_lock);
363 kmem_cache_free(rp->e_slab, ep);
367 static int mon_text_release(struct inode *inode, struct file *file)
369 struct mon_reader_text *rp = file->private_data;
370 struct mon_bus *mbus;
371 /* unsigned long flags; */
373 struct mon_event_text *ep;
375 mutex_lock(&mon_lock);
376 mbus = inode->u.generic_ip;
378 if (mbus->nreaders <= 0) {
379 printk(KERN_ERR TAG ": consistency error on close\n");
380 mutex_unlock(&mon_lock);
383 mon_reader_del(mbus, &rp->r);
386 * In theory, e_list is protected by mbus->lock. However,
387 * after mon_reader_del has finished, the following is the case:
388 * - we are not on reader list anymore, so new events won't be added;
389 * - whole mbus may be dropped if it was orphaned.
390 * So, we better not touch mbus.
392 /* spin_lock_irqsave(&mbus->lock, flags); */
393 while (!list_empty(&rp->e_list)) {
395 ep = list_entry(p, struct mon_event_text, e_link);
398 kmem_cache_free(rp->e_slab, ep);
400 /* spin_unlock_irqrestore(&mbus->lock, flags); */
402 kmem_cache_destroy(rp->e_slab);
403 kfree(rp->printf_buf);
406 mutex_unlock(&mon_lock);
410 struct file_operations mon_fops_text = {
411 .owner = THIS_MODULE,
412 .open = mon_text_open,
414 .read = mon_text_read,
415 /* .write = mon_text_write, */
416 /* .poll = mon_text_poll, */
417 /* .ioctl = mon_text_ioctl, */
418 .release = mon_text_release,
422 * Slab interface: constructor.
424 static void mon_text_ctor(void *mem, kmem_cache_t *slab, unsigned long sflags)
427 * Nothing to initialize. No, really!
428 * So, we fill it with garbage to emulate a reused object.
430 memset(mem, 0xe5, sizeof(struct mon_event_text));
433 static void mon_text_dtor(void *mem, kmem_cache_t *slab, unsigned long sflags)