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