1 /* 2 * The USB Monitor, inspired by Dave Harding's USBMon. 3 * 4 * This is a text format reader. 5 */ 6 7 #include <linux/kernel.h> 8 #include <linux/list.h> 9 #include <linux/usb.h> 10 #include <linux/time.h> 11 #include <asm/uaccess.h> 12 13 #include "usb_mon.h" 14 15 /* 16 * No, we do not want arbitrarily long data strings. 17 * Use the binary interface if you want to capture bulk data! 18 */ 19 #define DATA_MAX 32 20 21 /* 22 * Defined by USB 2.0 clause 9.3, table 9.2. 23 */ 24 #define SETUP_MAX 8 25 26 /* 27 * This limit exists to prevent OOMs when the user process stops reading. 28 */ 29 #define EVENT_MAX 25 30 31 #define PRINTF_DFL 130 32 33 struct mon_event_text { 34 struct list_head e_link; 35 int type; /* submit, complete, etc. */ 36 unsigned int pipe; /* Pipe */ 37 unsigned long id; /* From pointer, most of the time */ 38 unsigned int tstamp; 39 int length; /* Depends on type: xfer length or act length */ 40 int status; 41 char setup_flag; 42 char data_flag; 43 unsigned char setup[SETUP_MAX]; 44 unsigned char data[DATA_MAX]; 45 }; 46 47 #define SLAB_NAME_SZ 30 48 struct mon_reader_text { 49 kmem_cache_t *e_slab; 50 int nevents; 51 struct list_head e_list; 52 struct mon_reader r; /* In C, parent class can be placed anywhere */ 53 54 wait_queue_head_t wait; 55 int printf_size; 56 char *printf_buf; 57 struct semaphore printf_lock; 58 59 char slab_name[SLAB_NAME_SZ]; 60 }; 61 62 static void mon_text_ctor(void *, kmem_cache_t *, unsigned long); 63 static void mon_text_dtor(void *, kmem_cache_t *, unsigned long); 64 65 /* 66 * mon_text_submit 67 * mon_text_complete 68 * 69 * May be called from an interrupt. 70 * 71 * This is called with the whole mon_bus locked, so no additional lock. 72 */ 73 74 static inline char mon_text_get_setup(struct mon_event_text *ep, 75 struct urb *urb, char ev_type) 76 { 77 78 if (!usb_pipecontrol(urb->pipe) || ev_type != 'S') 79 return '-'; 80 81 if (urb->transfer_flags & URB_NO_SETUP_DMA_MAP) 82 return 'D'; 83 if (urb->setup_packet == NULL) 84 return 'Z'; /* '0' would be not as pretty. */ 85 86 memcpy(ep->setup, urb->setup_packet, SETUP_MAX); 87 return 0; 88 } 89 90 static inline char mon_text_get_data(struct mon_event_text *ep, struct urb *urb, 91 int len, char ev_type) 92 { 93 int pipe = urb->pipe; 94 unsigned char *data; 95 96 /* 97 * The check to see if it's safe to poke at data has an enormous 98 * number of corner cases, but it seems that the following is 99 * more or less safe. 100 * 101 * We do not even try to look transfer_buffer, because it can 102 * contain non-NULL garbage in case the upper level promised to 103 * set DMA for the HCD. 104 */ 105 if (urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP) 106 return 'D'; 107 108 if (len <= 0) 109 return 'L'; 110 111 if ((data = urb->transfer_buffer) == NULL) 112 return 'Z'; /* '0' would be not as pretty. */ 113 114 /* 115 * Bulk is easy to shortcut reliably. 116 * XXX Other pipe types need consideration. Currently, we overdo it 117 * and collect garbage for them: better more than less. 118 */ 119 if (usb_pipebulk(pipe) || usb_pipecontrol(pipe)) { 120 if (usb_pipein(pipe)) { 121 if (ev_type == 'S') 122 return '<'; 123 } else { 124 if (ev_type == 'C') 125 return '>'; 126 } 127 } 128 129 if (len >= DATA_MAX) 130 len = DATA_MAX; 131 memcpy(ep->data, urb->transfer_buffer, len); 132 return 0; 133 } 134 135 static inline unsigned int mon_get_timestamp(void) 136 { 137 struct timeval tval; 138 unsigned int stamp; 139 140 do_gettimeofday(&tval); 141 stamp = tval.tv_sec & 0xFFFF; /* 2^32 = 4294967296. Limit to 4096s. */ 142 stamp = stamp * 1000000 + tval.tv_usec; 143 return stamp; 144 } 145 146 static void mon_text_event(struct mon_reader_text *rp, struct urb *urb, 147 char ev_type) 148 { 149 struct mon_event_text *ep; 150 unsigned int stamp; 151 152 stamp = mon_get_timestamp(); 153 154 if (rp->nevents >= EVENT_MAX || 155 (ep = kmem_cache_alloc(rp->e_slab, SLAB_ATOMIC)) == NULL) { 156 rp->r.m_bus->cnt_text_lost++; 157 return; 158 } 159 160 ep->type = ev_type; 161 ep->pipe = urb->pipe; 162 ep->id = (unsigned long) urb; 163 ep->tstamp = stamp; 164 ep->length = (ev_type == 'S') ? 165 urb->transfer_buffer_length : urb->actual_length; 166 /* Collecting status makes debugging sense for submits, too */ 167 ep->status = urb->status; 168 169 ep->setup_flag = mon_text_get_setup(ep, urb, ev_type); 170 ep->data_flag = mon_text_get_data(ep, urb, ep->length, ev_type); 171 172 rp->nevents++; 173 list_add_tail(&ep->e_link, &rp->e_list); 174 wake_up(&rp->wait); 175 } 176 177 static void mon_text_submit(void *data, struct urb *urb) 178 { 179 struct mon_reader_text *rp = data; 180 mon_text_event(rp, urb, 'S'); 181 } 182 183 static void mon_text_complete(void *data, struct urb *urb) 184 { 185 struct mon_reader_text *rp = data; 186 mon_text_event(rp, urb, 'C'); 187 } 188 189 /* 190 * Fetch next event from the circular buffer. 191 */ 192 static struct mon_event_text *mon_text_fetch(struct mon_reader_text *rp, 193 struct mon_bus *mbus) 194 { 195 struct list_head *p; 196 unsigned long flags; 197 198 spin_lock_irqsave(&mbus->lock, flags); 199 if (list_empty(&rp->e_list)) { 200 spin_unlock_irqrestore(&mbus->lock, flags); 201 return NULL; 202 } 203 p = rp->e_list.next; 204 list_del(p); 205 --rp->nevents; 206 spin_unlock_irqrestore(&mbus->lock, flags); 207 return list_entry(p, struct mon_event_text, e_link); 208 } 209 210 /* 211 */ 212 static int mon_text_open(struct inode *inode, struct file *file) 213 { 214 struct mon_bus *mbus; 215 struct usb_bus *ubus; 216 struct mon_reader_text *rp; 217 int rc; 218 219 down(&mon_lock); 220 mbus = inode->u.generic_ip; 221 ubus = mbus->u_bus; 222 223 rp = kmalloc(sizeof(struct mon_reader_text), GFP_KERNEL); 224 if (rp == NULL) { 225 rc = -ENOMEM; 226 goto err_alloc; 227 } 228 memset(rp, 0, sizeof(struct mon_reader_text)); 229 INIT_LIST_HEAD(&rp->e_list); 230 init_waitqueue_head(&rp->wait); 231 init_MUTEX(&rp->printf_lock); 232 233 rp->printf_size = PRINTF_DFL; 234 rp->printf_buf = kmalloc(rp->printf_size, GFP_KERNEL); 235 if (rp->printf_buf == NULL) { 236 rc = -ENOMEM; 237 goto err_alloc_pr; 238 } 239 240 rp->r.m_bus = mbus; 241 rp->r.r_data = rp; 242 rp->r.rnf_submit = mon_text_submit; 243 rp->r.rnf_complete = mon_text_complete; 244 245 snprintf(rp->slab_name, SLAB_NAME_SZ, "mon%dt_%lx", ubus->busnum, 246 (long)rp); 247 rp->e_slab = kmem_cache_create(rp->slab_name, 248 sizeof(struct mon_event_text), sizeof(long), 0, 249 mon_text_ctor, mon_text_dtor); 250 if (rp->e_slab == NULL) { 251 rc = -ENOMEM; 252 goto err_slab; 253 } 254 255 mon_reader_add(mbus, &rp->r); 256 257 file->private_data = rp; 258 up(&mon_lock); 259 return 0; 260 261 // err_busy: 262 // kmem_cache_destroy(rp->e_slab); 263 err_slab: 264 kfree(rp->printf_buf); 265 err_alloc_pr: 266 kfree(rp); 267 err_alloc: 268 up(&mon_lock); 269 return rc; 270 } 271 272 /* 273 * For simplicity, we read one record in one system call and throw out 274 * what does not fit. This means that the following does not work: 275 * dd if=/dbg/usbmon/0t bs=10 276 * Also, we do not allow seeks and do not bother advancing the offset. 277 */ 278 static ssize_t mon_text_read(struct file *file, char __user *buf, 279 size_t nbytes, loff_t *ppos) 280 { 281 struct mon_reader_text *rp = file->private_data; 282 struct mon_bus *mbus = rp->r.m_bus; 283 DECLARE_WAITQUEUE(waita, current); 284 struct mon_event_text *ep; 285 int cnt, limit; 286 char *pbuf; 287 char udir, utype; 288 int data_len, i; 289 290 add_wait_queue(&rp->wait, &waita); 291 set_current_state(TASK_INTERRUPTIBLE); 292 while ((ep = mon_text_fetch(rp, mbus)) == NULL) { 293 if (file->f_flags & O_NONBLOCK) { 294 set_current_state(TASK_RUNNING); 295 remove_wait_queue(&rp->wait, &waita); 296 return -EWOULDBLOCK; /* Same as EAGAIN in Linux */ 297 } 298 /* 299 * We do not count nwaiters, because ->release is supposed 300 * to be called when all openers are gone only. 301 */ 302 schedule(); 303 if (signal_pending(current)) { 304 remove_wait_queue(&rp->wait, &waita); 305 return -EINTR; 306 } 307 set_current_state(TASK_INTERRUPTIBLE); 308 } 309 set_current_state(TASK_RUNNING); 310 remove_wait_queue(&rp->wait, &waita); 311 312 down(&rp->printf_lock); 313 cnt = 0; 314 pbuf = rp->printf_buf; 315 limit = rp->printf_size; 316 317 udir = usb_pipein(ep->pipe) ? 'i' : 'o'; 318 switch (usb_pipetype(ep->pipe)) { 319 case PIPE_ISOCHRONOUS: utype = 'Z'; break; 320 case PIPE_INTERRUPT: utype = 'I'; break; 321 case PIPE_CONTROL: utype = 'C'; break; 322 default: /* PIPE_BULK */ utype = 'B'; 323 } 324 cnt += snprintf(pbuf + cnt, limit - cnt, 325 "%lx %u %c %c%c:%03u:%02u", 326 ep->id, ep->tstamp, ep->type, 327 utype, udir, usb_pipedevice(ep->pipe), usb_pipeendpoint(ep->pipe)); 328 329 if (ep->setup_flag == 0) { /* Setup packet is present and captured */ 330 cnt += snprintf(pbuf + cnt, limit - cnt, 331 " s %02x %02x %04x %04x %04x", 332 ep->setup[0], 333 ep->setup[1], 334 (ep->setup[3] << 8) | ep->setup[2], 335 (ep->setup[5] << 8) | ep->setup[4], 336 (ep->setup[7] << 8) | ep->setup[6]); 337 } else if (ep->setup_flag != '-') { /* Unable to capture setup packet */ 338 cnt += snprintf(pbuf + cnt, limit - cnt, 339 " %c __ __ ____ ____ ____", ep->setup_flag); 340 } else { /* No setup for this kind of URB */ 341 cnt += snprintf(pbuf + cnt, limit - cnt, " %d", ep->status); 342 } 343 cnt += snprintf(pbuf + cnt, limit - cnt, " %d", ep->length); 344 345 if ((data_len = ep->length) > 0) { 346 if (ep->data_flag == 0) { 347 cnt += snprintf(pbuf + cnt, limit - cnt, " ="); 348 if (data_len >= DATA_MAX) 349 data_len = DATA_MAX; 350 for (i = 0; i < data_len; i++) { 351 if (i % 4 == 0) { 352 cnt += snprintf(pbuf + cnt, limit - cnt, 353 " "); 354 } 355 cnt += snprintf(pbuf + cnt, limit - cnt, 356 "%02x", ep->data[i]); 357 } 358 cnt += snprintf(pbuf + cnt, limit - cnt, "\n"); 359 } else { 360 cnt += snprintf(pbuf + cnt, limit - cnt, 361 " %c\n", ep->data_flag); 362 } 363 } else { 364 cnt += snprintf(pbuf + cnt, limit - cnt, "\n"); 365 } 366 367 if (copy_to_user(buf, rp->printf_buf, cnt)) 368 cnt = -EFAULT; 369 up(&rp->printf_lock); 370 kmem_cache_free(rp->e_slab, ep); 371 return cnt; 372 } 373 374 static int mon_text_release(struct inode *inode, struct file *file) 375 { 376 struct mon_reader_text *rp = file->private_data; 377 struct mon_bus *mbus; 378 /* unsigned long flags; */ 379 struct list_head *p; 380 struct mon_event_text *ep; 381 382 down(&mon_lock); 383 mbus = inode->u.generic_ip; 384 385 if (mbus->nreaders <= 0) { 386 printk(KERN_ERR TAG ": consistency error on close\n"); 387 up(&mon_lock); 388 return 0; 389 } 390 mon_reader_del(mbus, &rp->r); 391 392 /* 393 * In theory, e_list is protected by mbus->lock. However, 394 * after mon_reader_del has finished, the following is the case: 395 * - we are not on reader list anymore, so new events won't be added; 396 * - whole mbus may be dropped if it was orphaned. 397 * So, we better not touch mbus. 398 */ 399 /* spin_lock_irqsave(&mbus->lock, flags); */ 400 while (!list_empty(&rp->e_list)) { 401 p = rp->e_list.next; 402 ep = list_entry(p, struct mon_event_text, e_link); 403 list_del(p); 404 --rp->nevents; 405 kmem_cache_free(rp->e_slab, ep); 406 } 407 /* spin_unlock_irqrestore(&mbus->lock, flags); */ 408 409 kmem_cache_destroy(rp->e_slab); 410 kfree(rp->printf_buf); 411 kfree(rp); 412 413 up(&mon_lock); 414 return 0; 415 } 416 417 struct file_operations mon_fops_text = { 418 .owner = THIS_MODULE, 419 .open = mon_text_open, 420 .llseek = no_llseek, 421 .read = mon_text_read, 422 /* .write = mon_text_write, */ 423 /* .poll = mon_text_poll, */ 424 /* .ioctl = mon_text_ioctl, */ 425 .release = mon_text_release, 426 }; 427 428 /* 429 * Slab interface: constructor. 430 */ 431 static void mon_text_ctor(void *mem, kmem_cache_t *slab, unsigned long sflags) 432 { 433 /* 434 * Nothing to initialize. No, really! 435 * So, we fill it with garbage to emulate a reused object. 436 */ 437 memset(mem, 0xe5, sizeof(struct mon_event_text)); 438 } 439 440 static void mon_text_dtor(void *mem, kmem_cache_t *slab, unsigned long sflags) 441 { 442 ; 443 } 444