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1 /*
2  * Copyright (C) 2007 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #define TRACE_TAG USB
18 
19 #include "sysdeps.h"
20 
21 #include <ctype.h>
22 #include <dirent.h>
23 #include <errno.h>
24 #include <fcntl.h>
25 #include <linux/usb/ch9.h>
26 #include <linux/usbdevice_fs.h>
27 #include <linux/version.h>
28 #include <stdio.h>
29 #include <stdlib.h>
30 #include <string.h>
31 #include <sys/ioctl.h>
32 #include <sys/time.h>
33 #include <sys/sysmacros.h>
34 #include <sys/types.h>
35 #include <unistd.h>
36 
37 #include <chrono>
38 #include <condition_variable>
39 #include <list>
40 #include <mutex>
41 #include <string>
42 #include <string_view>
43 #include <thread>
44 
45 #include <android-base/file.h>
46 #include <android-base/stringprintf.h>
47 #include <android-base/strings.h>
48 
49 #include "adb.h"
50 #include "transport.h"
51 #include "usb.h"
52 
53 using namespace std::chrono_literals;
54 using namespace std::literals;
55 
56 /* usb scan debugging is waaaay too verbose */
57 #define DBGX(x...)
58 
59 namespace native {
60 struct usb_handle : public ::usb_handle {
~usb_handlenative::usb_handle61     ~usb_handle() {
62       if (fd != -1) unix_close(fd);
63     }
64 
65     std::string path;
66     int fd = -1;
67     unsigned char ep_in;
68     unsigned char ep_out;
69 
70     size_t max_packet_size;
71     unsigned zero_mask;
72     unsigned writeable = 1;
73 
74     usbdevfs_urb urb_in;
75     usbdevfs_urb urb_out;
76 
77     bool urb_in_busy = false;
78     bool urb_out_busy = false;
79     bool dead = false;
80 
81     std::condition_variable cv;
82     std::mutex mutex;
83 
84     // for garbage collecting disconnected devices
85     bool mark;
86 
87     // ID of thread currently in REAPURB
88     pthread_t reaper_thread = 0;
89 };
90 
91 static auto& g_usb_handles_mutex = *new std::mutex();
92 static auto& g_usb_handles = *new std::list<usb_handle*>();
93 
is_known_device(std::string_view dev_name)94 static int is_known_device(std::string_view dev_name) {
95     std::lock_guard<std::mutex> lock(g_usb_handles_mutex);
96     for (usb_handle* usb : g_usb_handles) {
97         if (usb->path == dev_name) {
98             // set mark flag to indicate this device is still alive
99             usb->mark = true;
100             return 1;
101         }
102     }
103     return 0;
104 }
105 
kick_disconnected_devices()106 static void kick_disconnected_devices() {
107     std::lock_guard<std::mutex> lock(g_usb_handles_mutex);
108     // kick any devices in the device list that were not found in the device scan
109     for (usb_handle* usb : g_usb_handles) {
110         if (!usb->mark) {
111             usb_kick(usb);
112         } else {
113             usb->mark = false;
114         }
115     }
116 }
117 
contains_non_digit(const char * name)118 static inline bool contains_non_digit(const char* name) {
119     while (*name) {
120         if (!isdigit(*name++)) return true;
121     }
122     return false;
123 }
124 
find_usb_device(const std::string & base,void (* register_device_callback)(const char *,const char *,unsigned char,unsigned char,int,int,unsigned,size_t))125 static void find_usb_device(const std::string& base,
126                             void (*register_device_callback)(const char*, const char*,
127                                                              unsigned char, unsigned char, int, int,
128                                                              unsigned, size_t)) {
129     std::unique_ptr<DIR, int(*)(DIR*)> bus_dir(opendir(base.c_str()), closedir);
130     if (!bus_dir) return;
131 
132     dirent* de;
133     while ((de = readdir(bus_dir.get())) != nullptr) {
134         if (contains_non_digit(de->d_name)) continue;
135 
136         std::string bus_name = base + "/" + de->d_name;
137 
138         std::unique_ptr<DIR, int(*)(DIR*)> dev_dir(opendir(bus_name.c_str()), closedir);
139         if (!dev_dir) continue;
140 
141         while ((de = readdir(dev_dir.get()))) {
142             unsigned char devdesc[4096];
143             unsigned char* bufptr = devdesc;
144             unsigned char* bufend;
145             struct usb_device_descriptor* device;
146             struct usb_config_descriptor* config;
147             struct usb_interface_descriptor* interface;
148             struct usb_endpoint_descriptor *ep1, *ep2;
149             unsigned zero_mask = 0;
150             size_t max_packet_size = 0;
151             unsigned vid, pid;
152 
153             if (contains_non_digit(de->d_name)) continue;
154 
155             std::string dev_name = bus_name + "/" + de->d_name;
156             if (is_known_device(dev_name)) {
157                 continue;
158             }
159 
160             int fd = unix_open(dev_name, O_RDONLY | O_CLOEXEC);
161             if (fd == -1) {
162                 continue;
163             }
164 
165             size_t desclength = unix_read(fd, devdesc, sizeof(devdesc));
166             bufend = bufptr + desclength;
167 
168                 // should have device and configuration descriptors, and atleast two endpoints
169             if (desclength < USB_DT_DEVICE_SIZE + USB_DT_CONFIG_SIZE) {
170                 D("desclength %zu is too small", desclength);
171                 unix_close(fd);
172                 continue;
173             }
174 
175             device = (struct usb_device_descriptor*)bufptr;
176             bufptr += USB_DT_DEVICE_SIZE;
177 
178             if((device->bLength != USB_DT_DEVICE_SIZE) || (device->bDescriptorType != USB_DT_DEVICE)) {
179                 unix_close(fd);
180                 continue;
181             }
182 
183             vid = device->idVendor;
184             pid = device->idProduct;
185             DBGX("[ %s is V:%04x P:%04x ]\n", dev_name.c_str(), vid, pid);
186 
187                 // should have config descriptor next
188             config = (struct usb_config_descriptor *)bufptr;
189             bufptr += USB_DT_CONFIG_SIZE;
190             if (config->bLength != USB_DT_CONFIG_SIZE || config->bDescriptorType != USB_DT_CONFIG) {
191                 D("usb_config_descriptor not found");
192                 unix_close(fd);
193                 continue;
194             }
195 
196                 // loop through all the descriptors and look for the ADB interface
197             while (bufptr < bufend) {
198                 unsigned char length = bufptr[0];
199                 unsigned char type = bufptr[1];
200 
201                 if (type == USB_DT_INTERFACE) {
202                     interface = (struct usb_interface_descriptor *)bufptr;
203                     bufptr += length;
204 
205                     if (length != USB_DT_INTERFACE_SIZE) {
206                         D("interface descriptor has wrong size");
207                         break;
208                     }
209 
210                     DBGX("bInterfaceClass: %d,  bInterfaceSubClass: %d,"
211                          "bInterfaceProtocol: %d, bNumEndpoints: %d\n",
212                          interface->bInterfaceClass, interface->bInterfaceSubClass,
213                          interface->bInterfaceProtocol, interface->bNumEndpoints);
214 
215                     if (interface->bNumEndpoints == 2 &&
216                         is_adb_interface(interface->bInterfaceClass, interface->bInterfaceSubClass,
217                                          interface->bInterfaceProtocol)) {
218                         struct stat st;
219                         char pathbuf[128];
220                         char link[256];
221                         char *devpath = nullptr;
222 
223                         DBGX("looking for bulk endpoints\n");
224                             // looks like ADB...
225                         ep1 = (struct usb_endpoint_descriptor *)bufptr;
226                         bufptr += USB_DT_ENDPOINT_SIZE;
227                             // For USB 3.0 SuperSpeed devices, skip potential
228                             // USB 3.0 SuperSpeed Endpoint Companion descriptor
229                         if (bufptr+2 <= devdesc + desclength &&
230                             bufptr[0] == USB_DT_SS_EP_COMP_SIZE &&
231                             bufptr[1] == USB_DT_SS_ENDPOINT_COMP) {
232                             bufptr += USB_DT_SS_EP_COMP_SIZE;
233                         }
234                         ep2 = (struct usb_endpoint_descriptor *)bufptr;
235                         bufptr += USB_DT_ENDPOINT_SIZE;
236                         if (bufptr+2 <= devdesc + desclength &&
237                             bufptr[0] == USB_DT_SS_EP_COMP_SIZE &&
238                             bufptr[1] == USB_DT_SS_ENDPOINT_COMP) {
239                             bufptr += USB_DT_SS_EP_COMP_SIZE;
240                         }
241 
242                         if (bufptr > devdesc + desclength ||
243                             ep1->bLength != USB_DT_ENDPOINT_SIZE ||
244                             ep1->bDescriptorType != USB_DT_ENDPOINT ||
245                             ep2->bLength != USB_DT_ENDPOINT_SIZE ||
246                             ep2->bDescriptorType != USB_DT_ENDPOINT) {
247                             D("endpoints not found");
248                             break;
249                         }
250 
251                             // both endpoints should be bulk
252                         if (ep1->bmAttributes != USB_ENDPOINT_XFER_BULK ||
253                             ep2->bmAttributes != USB_ENDPOINT_XFER_BULK) {
254                             D("bulk endpoints not found");
255                             continue;
256                         }
257                             /* aproto 01 needs 0 termination */
258                         if (interface->bInterfaceProtocol == ADB_PROTOCOL) {
259                             max_packet_size = ep1->wMaxPacketSize;
260                             zero_mask = ep1->wMaxPacketSize - 1;
261                         }
262 
263                             // we have a match.  now we just need to figure out which is in and which is out.
264                         unsigned char local_ep_in, local_ep_out;
265                         if (ep1->bEndpointAddress & USB_ENDPOINT_DIR_MASK) {
266                             local_ep_in = ep1->bEndpointAddress;
267                             local_ep_out = ep2->bEndpointAddress;
268                         } else {
269                             local_ep_in = ep2->bEndpointAddress;
270                             local_ep_out = ep1->bEndpointAddress;
271                         }
272 
273                             // Determine the device path
274                         if (!fstat(fd, &st) && S_ISCHR(st.st_mode)) {
275                             snprintf(pathbuf, sizeof(pathbuf), "/sys/dev/char/%d:%d",
276                                      major(st.st_rdev), minor(st.st_rdev));
277                             ssize_t link_len = readlink(pathbuf, link, sizeof(link) - 1);
278                             if (link_len > 0) {
279                                 link[link_len] = '\0';
280                                 const char* slash = strrchr(link, '/');
281                                 if (slash) {
282                                     snprintf(pathbuf, sizeof(pathbuf),
283                                              "usb:%s", slash + 1);
284                                     devpath = pathbuf;
285                                 }
286                             }
287                         }
288 
289                         register_device_callback(dev_name.c_str(), devpath, local_ep_in,
290                                                  local_ep_out, interface->bInterfaceNumber,
291                                                  device->iSerialNumber, zero_mask, max_packet_size);
292                         break;
293                     }
294                 } else {
295                     bufptr += length;
296                 }
297             } // end of while
298 
299             unix_close(fd);
300         }
301     }
302 }
303 
usb_bulk_write(usb_handle * h,const void * data,int len)304 static int usb_bulk_write(usb_handle* h, const void* data, int len) {
305     std::unique_lock<std::mutex> lock(h->mutex);
306     D("++ usb_bulk_write ++");
307 
308     usbdevfs_urb* urb = &h->urb_out;
309     memset(urb, 0, sizeof(*urb));
310     urb->type = USBDEVFS_URB_TYPE_BULK;
311     urb->endpoint = h->ep_out;
312     urb->status = -1;
313     urb->buffer = const_cast<void*>(data);
314     urb->buffer_length = len;
315 
316     if (h->dead) {
317         errno = EINVAL;
318         return -1;
319     }
320 
321     if (TEMP_FAILURE_RETRY(ioctl(h->fd, USBDEVFS_SUBMITURB, urb)) == -1) {
322         return -1;
323     }
324 
325     h->urb_out_busy = true;
326     while (true) {
327         auto now = std::chrono::system_clock::now();
328         if (h->cv.wait_until(lock, now + 5s) == std::cv_status::timeout || h->dead) {
329             // TODO: call USBDEVFS_DISCARDURB?
330             errno = ETIMEDOUT;
331             return -1;
332         }
333         if (!h->urb_out_busy) {
334             if (urb->status != 0) {
335                 errno = -urb->status;
336                 return -1;
337             }
338             return urb->actual_length;
339         }
340     }
341 }
342 
usb_bulk_read(usb_handle * h,void * data,int len)343 static int usb_bulk_read(usb_handle* h, void* data, int len) {
344     std::unique_lock<std::mutex> lock(h->mutex);
345     D("++ usb_bulk_read ++");
346 
347     usbdevfs_urb* urb = &h->urb_in;
348     memset(urb, 0, sizeof(*urb));
349     urb->type = USBDEVFS_URB_TYPE_BULK;
350     urb->endpoint = h->ep_in;
351     urb->status = -1;
352     urb->buffer = data;
353     urb->buffer_length = len;
354 
355     if (h->dead) {
356         errno = EINVAL;
357         return -1;
358     }
359 
360     if (TEMP_FAILURE_RETRY(ioctl(h->fd, USBDEVFS_SUBMITURB, urb)) == -1) {
361         return -1;
362     }
363 
364     h->urb_in_busy = true;
365     while (true) {
366         D("[ reap urb - wait ]");
367         h->reaper_thread = pthread_self();
368         int fd = h->fd;
369         lock.unlock();
370 
371         // This ioctl must not have TEMP_FAILURE_RETRY because we send SIGALRM to break out.
372         usbdevfs_urb* out = nullptr;
373         int res = ioctl(fd, USBDEVFS_REAPURB, &out);
374         int saved_errno = errno;
375 
376         lock.lock();
377         h->reaper_thread = 0;
378         if (h->dead) {
379             errno = EINVAL;
380             return -1;
381         }
382         if (res < 0) {
383             if (saved_errno == EINTR) {
384                 continue;
385             }
386             D("[ reap urb - error ]");
387             errno = saved_errno;
388             return -1;
389         }
390         D("[ urb @%p status = %d, actual = %d ]", out, out->status, out->actual_length);
391 
392         if (out == &h->urb_in) {
393             D("[ reap urb - IN complete ]");
394             h->urb_in_busy = false;
395             if (urb->status != 0) {
396                 errno = -urb->status;
397                 return -1;
398             }
399             return urb->actual_length;
400         }
401         if (out == &h->urb_out) {
402             D("[ reap urb - OUT compelete ]");
403             h->urb_out_busy = false;
404             h->cv.notify_all();
405         }
406     }
407 }
408 
usb_write(usb_handle * h,const void * _data,int len)409 int usb_write(usb_handle *h, const void *_data, int len)
410 {
411     D("++ usb_write ++");
412 
413     unsigned char *data = (unsigned char*) _data;
414     int n = usb_bulk_write(h, data, len);
415     if (n != len) {
416         D("ERROR: n = %d, errno = %d (%s)", n, errno, strerror(errno));
417         return -1;
418     }
419 
420     if (h->zero_mask && !(len & h->zero_mask)) {
421         // If we need 0-markers and our transfer is an even multiple of the packet size,
422         // then send a zero marker.
423         return usb_bulk_write(h, _data, 0) == 0 ? n : -1;
424     }
425 
426     D("-- usb_write --");
427     return n;
428 }
429 
usb_read(usb_handle * h,void * _data,int len)430 int usb_read(usb_handle *h, void *_data, int len)
431 {
432     unsigned char *data = (unsigned char*) _data;
433     int n;
434 
435     D("++ usb_read ++");
436     int orig_len = len;
437     while (len == orig_len) {
438         int xfer = len;
439 
440         D("[ usb read %d fd = %d], path=%s", xfer, h->fd, h->path.c_str());
441         n = usb_bulk_read(h, data, xfer);
442         D("[ usb read %d ] = %d, path=%s", xfer, n, h->path.c_str());
443         if (n <= 0) {
444             if((errno == ETIMEDOUT) && (h->fd != -1)) {
445                 D("[ timeout ]");
446                 continue;
447             }
448             D("ERROR: n = %d, errno = %d (%s)",
449                 n, errno, strerror(errno));
450             return -1;
451         }
452 
453         len -= n;
454         data += n;
455     }
456 
457     D("-- usb_read --");
458     return orig_len - len;
459 }
460 
usb_reset(usb_handle * h)461 void usb_reset(usb_handle* h) {
462     ioctl(h->fd, USBDEVFS_RESET);
463     usb_kick(h);
464 }
465 
usb_kick(usb_handle * h)466 void usb_kick(usb_handle* h) {
467     std::lock_guard<std::mutex> lock(h->mutex);
468     D("[ kicking %p (fd = %d) ]", h, h->fd);
469     if (!h->dead) {
470         h->dead = true;
471 
472         if (h->writeable) {
473             /* HACK ALERT!
474             ** Sometimes we get stuck in ioctl(USBDEVFS_REAPURB).
475             ** This is a workaround for that problem.
476             */
477             if (h->reaper_thread) {
478                 pthread_kill(h->reaper_thread, SIGALRM);
479             }
480 
481             /* cancel any pending transactions
482             ** these will quietly fail if the txns are not active,
483             ** but this ensures that a reader blocked on REAPURB
484             ** will get unblocked
485             */
486             ioctl(h->fd, USBDEVFS_DISCARDURB, &h->urb_in);
487             ioctl(h->fd, USBDEVFS_DISCARDURB, &h->urb_out);
488             h->urb_in.status = -ENODEV;
489             h->urb_out.status = -ENODEV;
490             h->urb_in_busy = false;
491             h->urb_out_busy = false;
492             h->cv.notify_all();
493         } else {
494             unregister_usb_transport(h);
495         }
496     }
497 }
498 
usb_close(usb_handle * h)499 int usb_close(usb_handle* h) {
500     std::lock_guard<std::mutex> lock(g_usb_handles_mutex);
501     g_usb_handles.remove(h);
502 
503     D("-- usb close %p (fd = %d) --", h, h->fd);
504 
505     delete h;
506 
507     return 0;
508 }
509 
usb_get_max_packet_size(usb_handle * h)510 size_t usb_get_max_packet_size(usb_handle* h) {
511     return h->max_packet_size;
512 }
513 
register_device(const char * dev_name,const char * dev_path,unsigned char ep_in,unsigned char ep_out,int interface,int serial_index,unsigned zero_mask,size_t max_packet_size)514 static void register_device(const char* dev_name, const char* dev_path, unsigned char ep_in,
515                             unsigned char ep_out, int interface, int serial_index,
516                             unsigned zero_mask, size_t max_packet_size) {
517     // Since Linux will not reassign the device ID (and dev_name) as long as the
518     // device is open, we can add to the list here once we open it and remove
519     // from the list when we're finally closed and everything will work out
520     // fine.
521     //
522     // If we have a usb_handle on the list of handles with a matching name, we
523     // have no further work to do.
524     {
525         std::lock_guard<std::mutex> lock(g_usb_handles_mutex);
526         for (usb_handle* usb: g_usb_handles) {
527             if (usb->path == dev_name) {
528                 return;
529             }
530         }
531     }
532 
533     D("[ usb located new device %s (%d/%d/%d) ]", dev_name, ep_in, ep_out, interface);
534     std::unique_ptr<usb_handle> usb(new usb_handle);
535     usb->path = dev_name;
536     usb->ep_in = ep_in;
537     usb->ep_out = ep_out;
538     usb->zero_mask = zero_mask;
539     usb->max_packet_size = max_packet_size;
540 
541     // Initialize mark so we don't get garbage collected after the device scan.
542     usb->mark = true;
543 
544     usb->fd = unix_open(usb->path, O_RDWR | O_CLOEXEC);
545     if (usb->fd == -1) {
546         // Opening RW failed, so see if we have RO access.
547         usb->fd = unix_open(usb->path, O_RDONLY | O_CLOEXEC);
548         if (usb->fd == -1) {
549             D("[ usb open %s failed: %s]", usb->path.c_str(), strerror(errno));
550             return;
551         }
552         usb->writeable = 0;
553     }
554 
555     D("[ usb opened %s%s, fd=%d]",
556       usb->path.c_str(), (usb->writeable ? "" : " (read-only)"), usb->fd);
557 
558     if (usb->writeable) {
559         if (ioctl(usb->fd, USBDEVFS_CLAIMINTERFACE, &interface) != 0) {
560             D("[ usb ioctl(%d, USBDEVFS_CLAIMINTERFACE) failed: %s]", usb->fd, strerror(errno));
561             return;
562         }
563     }
564 
565     // Read the device's serial number.
566     std::string serial_path = android::base::StringPrintf(
567         "/sys/bus/usb/devices/%s/serial", dev_path + 4);
568     std::string serial;
569     if (!android::base::ReadFileToString(serial_path, &serial)) {
570         D("[ usb read %s failed: %s ]", serial_path.c_str(), strerror(errno));
571         // We don't actually want to treat an unknown serial as an error because
572         // devices aren't able to communicate a serial number in early bringup.
573         // http://b/20883914
574         serial = "";
575     }
576     serial = android::base::Trim(serial);
577 
578     // Add to the end of the active handles.
579     usb_handle* done_usb = usb.release();
580     {
581         std::lock_guard<std::mutex> lock(g_usb_handles_mutex);
582         g_usb_handles.push_back(done_usb);
583     }
584     register_usb_transport(done_usb, serial.c_str(), dev_path, done_usb->writeable);
585 }
586 
device_poll_thread()587 static void device_poll_thread() {
588     adb_thread_setname("device poll");
589     D("Created device thread");
590     while (true) {
591         // TODO: Use inotify.
592         find_usb_device("/dev/bus/usb", register_device);
593         kick_disconnected_devices();
594         std::this_thread::sleep_for(1s);
595     }
596 }
597 
usb_init()598 void usb_init() {
599     struct sigaction actions;
600     memset(&actions, 0, sizeof(actions));
601     sigemptyset(&actions.sa_mask);
602     actions.sa_flags = 0;
603     actions.sa_handler = [](int) {};
604     sigaction(SIGALRM, &actions, nullptr);
605 
606     std::thread(device_poll_thread).detach();
607 }
608 
usb_cleanup()609 void usb_cleanup() {}
610 
611 } // namespace native
612