adb/usb_linux.c - platform/system/core - Git at Google

 /*
  * Copyright (C) 2007 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
 #include <string.h>

 #include <sys/ioctl.h>
 #include <sys/types.h>
 #include <dirent.h>
 #include <fcntl.h>
 #include <errno.h>
 #include <ctype.h>

 #include <linux/usbdevice_fs.h>
 #include <linux/version.h>
 #if LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 20)
 #include <linux/usb/ch9.h>
 #else
 #include <linux/usb_ch9.h>
 #endif
 #include <asm/byteorder.h>

 #include "sysdeps.h"

 #define   TRACE_TAG  TRACE_USB
 #include "adb.h"


 /* usb scan debugging is waaaay too verbose */
 #define DBGX(x...)

 static adb_mutex_t usb_lock = ADB_MUTEX_INITIALIZER;

 struct usb_handle
 {
     usb_handle *prev;
     usb_handle *next;

     char fname[64];
     int desc;
     unsigned char ep_in;
     unsigned char ep_out;

     unsigned zero_mask;

     struct usbdevfs_urb urb_in;
     struct usbdevfs_urb urb_out;

     int urb_in_busy;
     int urb_out_busy;
     int dead;

     adb_cond_t notify;
     adb_mutex_t lock;

     // for garbage collecting disconnected devices
     int mark;

     // ID of thread currently in REAPURB
     pthread_t reaper_thread;
 };

 static usb_handle handle_list = {
     .prev = &handle_list,
     .next = &handle_list,
 };

 static int known_device(const char *dev_name)
 {
     usb_handle *usb;

     adb_mutex_lock(&usb_lock);
     for(usb = handle_list.next; usb != &handle_list; usb = usb->next){
         if(!strcmp(usb->fname, dev_name)) {
             // set mark flag to indicate this device is still alive
             usb->mark = 1;
             adb_mutex_unlock(&usb_lock);
             return 1;
         }
     }
     adb_mutex_unlock(&usb_lock);
     return 0;
 }

 static void kick_disconnected_devices()
 {
     usb_handle *usb;

     adb_mutex_lock(&usb_lock);
     // kick any devices in the device list that were not found in the device scan
     for(usb = handle_list.next; usb != &handle_list; usb = usb->next){
         if (usb->mark == 0) {
             usb_kick(usb);
         } else {
             usb->mark = 0;
         }
     }
     adb_mutex_unlock(&usb_lock);

 }

 static void register_device(const char *dev_name, unsigned char ep_in, unsigned char ep_out,
                             int ifc, const char *serial, unsigned zero_mask);

 static inline int badname(const char *name)
 {
     while(*name) {
         if(!isdigit(*name++)) return 1;
     }
     return 0;
 }

 static int find_usb_device(const char *base,
                            void (*register_device_callback) (const char *, unsigned char, unsigned char, int, const char *, unsigned))
 {
     char busname[32], devname[32];
     unsigned char local_ep_in, local_ep_out;
     DIR *busdir , *devdir ;
     struct dirent *de;
     int fd ;
     int found_device = 0;
     char serial[256];

     busdir = opendir(base);
     if(busdir == 0) return 0;

     while((de = readdir(busdir)) != 0) {
         if(badname(de->d_name)) continue;

         snprintf(busname, sizeof busname, "%s/%s", base, de->d_name);
         devdir = opendir(busname);
         if(devdir == 0) continue;

 //        DBGX("[ scanning %s ]\n", busname);
         while((de = readdir(devdir))) {
             unsigned char devdesc[256];
             unsigned char* bufptr = devdesc;
             struct usb_device_descriptor* device;
             struct usb_config_descriptor* config;
             struct usb_interface_descriptor* interface;
             struct usb_endpoint_descriptor *ep1, *ep2;
             unsigned zero_mask = 0;
             unsigned vid, pid;
             int i, interfaces;
             size_t desclength;

             if(badname(de->d_name)) continue;
             snprintf(devname, sizeof devname, "%s/%s", busname, de->d_name);

             if(known_device(devname)) {
                 DBGX("skipping %s\n", devname);
                 continue;
             }

 //            DBGX("[ scanning %s ]\n", devname);
             if((fd = unix_open(devname, O_RDWR)) < 0) {
                 continue;
             }

             desclength = adb_read(fd, devdesc, sizeof(devdesc));

                 // should have device and configuration descriptors, and atleast two endpoints
             if (desclength < USB_DT_DEVICE_SIZE + USB_DT_CONFIG_SIZE) {
                 D("desclength %d is too small\n", desclength);
                 adb_close(fd);
                 continue;
             }

             device = (struct usb_device_descriptor*)bufptr;
             bufptr += USB_DT_DEVICE_SIZE;

             if((device->bLength != USB_DT_DEVICE_SIZE) || (device->bDescriptorType != USB_DT_DEVICE)) {
                 adb_close(fd);
                 continue;
             }

             vid = __le16_to_cpu(device->idVendor);
             pid = __le16_to_cpu(device->idProduct);
             pid = devdesc[10] | (devdesc[11] << 8);
             DBGX("[ %s is V:%04x P:%04x ]\n", devname, vid, pid);

                 // should have config descriptor next
             config = (struct usb_config_descriptor *)bufptr;
             bufptr += USB_DT_CONFIG_SIZE;
             if (config->bLength != USB_DT_CONFIG_SIZE || config->bDescriptorType != USB_DT_CONFIG) {
                 D("usb_config_descriptor not found\n");
                 adb_close(fd);
                 continue;
             }

                 // loop through all the interfaces and look for the ADB interface
             interfaces = config->bNumInterfaces;
             for (i = 0; i < interfaces; i++) {
                 if (bufptr + USB_DT_ENDPOINT_SIZE > devdesc + desclength)
                     break;

                 interface = (struct usb_interface_descriptor *)bufptr;
                 bufptr += USB_DT_INTERFACE_SIZE;
                 if (interface->bLength != USB_DT_INTERFACE_SIZE ||
                     interface->bDescriptorType != USB_DT_INTERFACE) {
                     D("usb_interface_descriptor not found\n");
                     break;
                 }

                 DBGX("bInterfaceClass: %d,  bInterfaceSubClass: %d,"
                      "bInterfaceProtocol: %d, bNumEndpoints: %d\n",
                      interface->bInterfaceClass, interface->bInterfaceSubClass,
                      interface->bInterfaceProtocol, interface->bNumEndpoints);

                 if (interface->bNumEndpoints == 2 &&
                         is_adb_interface(vid, pid, interface->bInterfaceClass,
                         interface->bInterfaceSubClass, interface->bInterfaceProtocol))  {

                     DBGX("looking for bulk endpoints\n");
                         // looks like ADB...
                     ep1 = (struct usb_endpoint_descriptor *)bufptr;
                     bufptr += USB_DT_ENDPOINT_SIZE;
                     ep2 = (struct usb_endpoint_descriptor *)bufptr;
                     bufptr += USB_DT_ENDPOINT_SIZE;

                     if (bufptr > devdesc + desclength ||
                         ep1->bLength != USB_DT_ENDPOINT_SIZE ||
                         ep1->bDescriptorType != USB_DT_ENDPOINT ||
                         ep2->bLength != USB_DT_ENDPOINT_SIZE ||
                         ep2->bDescriptorType != USB_DT_ENDPOINT) {
                         D("endpoints not found\n");
                         break;
                     }

                         // both endpoints should be bulk
                     if (ep1->bmAttributes != USB_ENDPOINT_XFER_BULK ||
                         ep2->bmAttributes != USB_ENDPOINT_XFER_BULK) {
                         D("bulk endpoints not found\n");
                         continue;
                     }

                         /* aproto 01 needs 0 termination */
                     if(interface->bInterfaceProtocol == 0x01) {
                         zero_mask = ep1->wMaxPacketSize - 1;
                     }

                         // we have a match.  now we just need to figure out which is in and which is out.
                     if (ep1->bEndpointAddress & USB_ENDPOINT_DIR_MASK) {
                         local_ep_in = ep1->bEndpointAddress;
                         local_ep_out = ep2->bEndpointAddress;
                     } else {
                         local_ep_in = ep2->bEndpointAddress;
                         local_ep_out = ep1->bEndpointAddress;
                     }

                         // read the device's serial number
                     serial[0] = 0;
                     memset(serial, 0, sizeof(serial));
                     if (device->iSerialNumber) {
                         struct usbdevfs_ctrltransfer  ctrl;
                         __u16 buffer[128];
                         int result;

                         memset(buffer, 0, sizeof(buffer));
                         memset(&ctrl, 0, sizeof(ctrl));

                         ctrl.bRequestType = USB_DIR_IN|USB_TYPE_STANDARD|USB_RECIP_DEVICE;
                         ctrl.bRequest = USB_REQ_GET_DESCRIPTOR;
                         ctrl.wValue = (USB_DT_STRING << 8) | device->iSerialNumber;
                         ctrl.wIndex = 0;
                         ctrl.wLength = sizeof(buffer);
                         ctrl.data = buffer;

                         result = ioctl(fd, USBDEVFS_CONTROL, &ctrl);
                         if (result > 0) {
                             int i;
                                 // skip first word, and copy the rest to the serial string, changing shorts to bytes.
                             result /= 2;
                             for (i = 1; i < result; i++)
                                 serial[i - 1] = buffer[i];
                             serial[i - 1] = 0;
                         }
                     }

                     register_device_callback(devname, local_ep_in, local_ep_out,
                             interface->bInterfaceNumber, serial, zero_mask);

                     found_device = 1;
                     break;
                 } else {
                         // skip to next interface
                     bufptr += (interface->bNumEndpoints * USB_DT_ENDPOINT_SIZE);
                 }
             } // end of for

             adb_close(fd);
         } // end of devdir while
         closedir(devdir);
     } //end of busdir while
     closedir(busdir);

     return found_device;
 }

 void usb_cleanup()
 {
 }

 static int usb_bulk_write(usb_handle *h, const void *data, int len)
 {
     struct usbdevfs_urb *urb = &h->urb_out;
     int res;

     memset(urb, 0, sizeof(*urb));
     urb->type = USBDEVFS_URB_TYPE_BULK;
     urb->endpoint = h->ep_out;
     urb->status = -1;
     urb->buffer = (void*) data;
     urb->buffer_length = len;

     D("++ write ++\n");

     adb_mutex_lock(&h->lock);
     if(h->dead) {
         res = -1;
         goto fail;
     }
     do {
         res = ioctl(h->desc, USBDEVFS_SUBMITURB, urb);
     } while((res < 0) && (errno == EINTR));

     if(res < 0) {
         goto fail;
     }

     res = -1;
     h->urb_out_busy = 1;
     for(;;) {
         adb_cond_wait(&h->notify, &h->lock);
         if(h->dead) {
             break;
         }
         if(h->urb_out_busy == 0) {
             if(urb->status == 0) {
                 res = urb->actual_length;
             }
             break;
         }
     }
 fail:
     adb_mutex_unlock(&h->lock);
     D("-- write --\n");
     return res;
 }

 static int usb_bulk_read(usb_handle *h, void *data, int len)
 {
     struct usbdevfs_urb *urb = &h->urb_in;
     struct usbdevfs_urb *out = NULL;
     int res;

     memset(urb, 0, sizeof(*urb));
     urb->type = USBDEVFS_URB_TYPE_BULK;
     urb->endpoint = h->ep_in;
     urb->status = -1;
     urb->buffer = data;
     urb->buffer_length = len;


     adb_mutex_lock(&h->lock);
     if(h->dead) {
         res = -1;
         goto fail;
     }
     do {
         res = ioctl(h->desc, USBDEVFS_SUBMITURB, urb);
     } while((res < 0) && (errno == EINTR));

     if(res < 0) {
         goto fail;
     }

     h->urb_in_busy = 1;
     for(;;) {
         D("[ reap urb - wait ]\n");
         h->reaper_thread = pthread_self();
         adb_mutex_unlock(&h->lock);
         res = ioctl(h->desc, USBDEVFS_REAPURB, &out);
         adb_mutex_lock(&h->lock);
         h->reaper_thread = 0;
         if(h->dead) {
             res = -1;
             break;
         }
         if(res < 0) {
             if(errno == EINTR) {
                 continue;
             }
             D("[ reap urb - error ]\n");
             break;
         }
         D("[ urb @%p status = %d, actual = %d ]\n",
             out, out->status, out->actual_length);

         if(out == &h->urb_in) {
             D("[ reap urb - IN complete ]\n");
             h->urb_in_busy = 0;
             if(urb->status == 0) {
                 res = urb->actual_length;
             } else {
                 res = -1;
             }
             break;
         }
         if(out == &h->urb_out) {
             D("[ reap urb - OUT compelete ]\n");
             h->urb_out_busy = 0;
             adb_cond_broadcast(&h->notify);
         }
     }
 fail:
     adb_mutex_unlock(&h->lock);
     return res;
 }


 int usb_write(usb_handle *h, const void *_data, int len)
 {
     unsigned char *data = (unsigned char*) _data;
     int n;
     int need_zero = 0;

     if(h->zero_mask) {
             /* if we need 0-markers and our transfer
             ** is an even multiple of the packet size,
             ** we make note of it
             */
         if(!(len & h->zero_mask)) {
             need_zero = 1;
         }
     }

     while(len > 0) {
         int xfer = (len > 4096) ? 4096 : len;

         n = usb_bulk_write(h, data, xfer);
         if(n != xfer) {
             D("ERROR: n = %d, errno = %d (%s)\n",
                 n, errno, strerror(errno));
             return -1;
         }

         len -= xfer;
         data += xfer;
     }

     if(need_zero){
         n = usb_bulk_write(h, _data, 0);
         return n;
     }

     return 0;
 }

 int usb_read(usb_handle *h, void *_data, int len)
 {
     unsigned char *data = (unsigned char*) _data;
     int n;

     D("++ usb_read ++\n");
     while(len > 0) {
         int xfer = (len > 4096) ? 4096 : len;

         D("[ usb read %d fd = %d], fname=%s\n", xfer, h->desc, h->fname);
         n = usb_bulk_read(h, data, xfer);
         D("[ usb read %d ] = %d, fname=%s\n", xfer, n, h->fname);
         if(n != xfer) {
             if((errno == ETIMEDOUT) && (h->desc != -1)) {
                 D("[ timeout ]\n");
                 if(n > 0){
                     data += n;
                     len -= n;
                 }
                 continue;
             }
             D("ERROR: n = %d, errno = %d (%s)\n",
                 n, errno, strerror(errno));
             return -1;
         }

         len -= xfer;
         data += xfer;
     }

     D("-- usb_read --\n");
     return 0;
 }

 void usb_kick(usb_handle *h)
 {
     D("[ kicking %p (fd = %d) ]\n", h, h->desc);
     adb_mutex_lock(&h->lock);
     if(h->dead == 0) {
         h->dead = 1;

         /* HACK ALERT!
         ** Sometimes we get stuck in ioctl(USBDEVFS_REAPURB).
         ** This is a workaround for that problem.
         */
         if (h->reaper_thread) {
             pthread_kill(h->reaper_thread, SIGALRM);
         }

         /* cancel any pending transactions
         ** these will quietly fail if the txns are not active,
         ** but this ensures that a reader blocked on REAPURB
         ** will get unblocked
         */
         ioctl(h->desc, USBDEVFS_DISCARDURB, &h->urb_in);
         ioctl(h->desc, USBDEVFS_DISCARDURB, &h->urb_out);
         h->urb_in.status = -ENODEV;
         h->urb_out.status = -ENODEV;
         h->urb_in_busy = 0;
         h->urb_out_busy = 0;
         adb_cond_broadcast(&h->notify);
     }
     adb_mutex_unlock(&h->lock);
 }

 int usb_close(usb_handle *h)
 {
     D("[ usb close ... ]\n");
     adb_mutex_lock(&usb_lock);
     h->next->prev = h->prev;
     h->prev->next = h->next;
     h->prev = 0;
     h->next = 0;

     adb_close(h->desc);
     D("[ usb closed %p (fd = %d) ]\n", h, h->desc);
     adb_mutex_unlock(&usb_lock);

     free(h);
     return 0;
 }

 static void register_device(const char *dev_name,
                             unsigned char ep_in, unsigned char ep_out,
                             int interface,
                             const char *serial, unsigned zero_mask)
 {
     usb_handle* usb = 0;
     int n = 0;

         /* Since Linux will not reassign the device ID (and dev_name)
         ** as long as the device is open, we can add to the list here
         ** once we open it and remove from the list when we're finally
         ** closed and everything will work out fine.
         **
         ** If we have a usb_handle on the list 'o handles with a matching
         ** name, we have no further work to do.
         */
     adb_mutex_lock(&usb_lock);
     for(usb = handle_list.next; usb != &handle_list; usb = usb->next){
         if(!strcmp(usb->fname, dev_name)) {
             adb_mutex_unlock(&usb_lock);
             return;
         }
     }
     adb_mutex_unlock(&usb_lock);

     D("[ usb located new device %s (%d/%d/%d) ]\n",
         dev_name, ep_in, ep_out, interface);
     usb = calloc(1, sizeof(usb_handle));
     strcpy(usb->fname, dev_name);
     usb->ep_in = ep_in;
     usb->ep_out = ep_out;
     usb->zero_mask = zero_mask;

     adb_cond_init(&usb->notify, 0);
     adb_mutex_init(&usb->lock, 0);
     /* initialize mark to 1 so we don't get garbage collected after the device scan */
     usb->mark = 1;
     usb->reaper_thread = 0;

     usb->desc = unix_open(usb->fname, O_RDWR);
     if(usb->desc < 0) goto fail;
     D("[ usb open %s fd = %d]\n", usb->fname, usb->desc);
     n = ioctl(usb->desc, USBDEVFS_CLAIMINTERFACE, &interface);
     if(n != 0) goto fail;

         /* add to the end of the active handles */
     adb_mutex_lock(&usb_lock);
     usb->next = &handle_list;
     usb->prev = handle_list.prev;
     usb->prev->next = usb;
     usb->next->prev = usb;
     adb_mutex_unlock(&usb_lock);

     register_usb_transport(usb, serial);
     return;

 fail:
     D("[ usb open %s error=%d, err_str = %s]\n",
         usb->fname,  errno, strerror(errno));
     if(usb->desc >= 0) {
         adb_close(usb->desc);
     }
     free(usb);
 }

 void* device_poll_thread(void* unused)
 {
     D("Created device thread\n");
     for(;;) {
             /* XXX use inotify */
         find_usb_device("/dev/bus/usb", register_device);
         kick_disconnected_devices();
         sleep(1);
     }
     return NULL;
 }

 static void sigalrm_handler(int signo)
 {
     // don't need to do anything here
 }

 void usb_init()
 {
     adb_thread_t tid;
     struct sigaction    actions;

     memset(&actions, 0, sizeof(actions));
     sigemptyset(&actions.sa_mask);
     actions.sa_flags = 0;
     actions.sa_handler = sigalrm_handler;
     sigaction(SIGALRM,& actions, NULL);

     if(adb_thread_create(&tid, device_poll_thread, NULL)){
         fatal_errno("cannot create input thread");
     }
 }
	/*
	* Copyright (C) 2007 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#include <stdio.h>
	#include <stdlib.h>
	#include <unistd.h>
	#include <string.h>

	#include <sys/ioctl.h>
	#include <sys/types.h>
	#include <dirent.h>
	#include <fcntl.h>
	#include <errno.h>
	#include <ctype.h>

	#include <linux/usbdevice_fs.h>
	#include <linux/version.h>
	#if LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 20)
	#include <linux/usb/ch9.h>
	#else
	#include <linux/usb_ch9.h>
	#endif
	#include <asm/byteorder.h>

	#include "sysdeps.h"

	#define TRACE_TAG TRACE_USB
	#include "adb.h"


	/* usb scan debugging is waaaay too verbose */
	#define DBGX(x...)

	static adb_mutex_t usb_lock = ADB_MUTEX_INITIALIZER;

	struct usb_handle
	{
	usb_handle *prev;
	usb_handle *next;

	char fname[64];
	int desc;
	unsigned char ep_in;
	unsigned char ep_out;

	unsigned zero_mask;

	struct usbdevfs_urb urb_in;
	struct usbdevfs_urb urb_out;

	int urb_in_busy;
	int urb_out_busy;
	int dead;

	adb_cond_t notify;
	adb_mutex_t lock;

	// for garbage collecting disconnected devices
	int mark;

	// ID of thread currently in REAPURB
	pthread_t reaper_thread;
	};

	static usb_handle handle_list = {
	.prev = &handle_list,
	.next = &handle_list,
	};

	static int known_device(const char *dev_name)
	{
	usb_handle *usb;

	adb_mutex_lock(&usb_lock);
	for(usb = handle_list.next; usb != &handle_list; usb = usb->next){
	if(!strcmp(usb->fname, dev_name)) {
	// set mark flag to indicate this device is still alive
	usb->mark = 1;
	adb_mutex_unlock(&usb_lock);
	return 1;
	}
	}
	adb_mutex_unlock(&usb_lock);
	return 0;
	}

	static void kick_disconnected_devices()
	{
	usb_handle *usb;

	adb_mutex_lock(&usb_lock);
	// kick any devices in the device list that were not found in the device scan
	for(usb = handle_list.next; usb != &handle_list; usb = usb->next){
	if (usb->mark == 0) {
	usb_kick(usb);
	} else {
	usb->mark = 0;
	}
	}
	adb_mutex_unlock(&usb_lock);

	}

	static void register_device(const char *dev_name, unsigned char ep_in, unsigned char ep_out,
	int ifc, const char *serial, unsigned zero_mask);

	static inline int badname(const char *name)
	{
	while(*name) {
	if(!isdigit(*name++)) return 1;
	}
	return 0;
	}

	static int find_usb_device(const char *base,
	void (register_device_callback) (const char , unsigned char, unsigned char, int, const char *, unsigned))
	{
	char busname[32], devname[32];
	unsigned char local_ep_in, local_ep_out;
	DIR busdir , devdir ;
	struct dirent *de;
	int fd ;
	int found_device = 0;
	char serial[256];

	busdir = opendir(base);
	if(busdir == 0) return 0;

	while((de = readdir(busdir)) != 0) {
	if(badname(de->d_name)) continue;

	snprintf(busname, sizeof busname, "%s/%s", base, de->d_name);
	devdir = opendir(busname);
	if(devdir == 0) continue;

	// DBGX("[ scanning %s ]\n", busname);
	while((de = readdir(devdir))) {
	unsigned char devdesc[256];
	unsigned char* bufptr = devdesc;
	struct usb_device_descriptor* device;
	struct usb_config_descriptor* config;
	struct usb_interface_descriptor* interface;
	struct usb_endpoint_descriptor ep1, ep2;
	unsigned zero_mask = 0;
	unsigned vid, pid;
	int i, interfaces;
	size_t desclength;

	if(badname(de->d_name)) continue;
	snprintf(devname, sizeof devname, "%s/%s", busname, de->d_name);

	if(known_device(devname)) {
	DBGX("skipping %s\n", devname);
	continue;
	}

	// DBGX("[ scanning %s ]\n", devname);
	if((fd = unix_open(devname, O_RDWR)) < 0) {
	continue;
	}

	desclength = adb_read(fd, devdesc, sizeof(devdesc));

	// should have device and configuration descriptors, and atleast two endpoints
	if (desclength < USB_DT_DEVICE_SIZE + USB_DT_CONFIG_SIZE) {
	D("desclength %d is too small\n", desclength);
	adb_close(fd);
	continue;
	}

	device = (struct usb_device_descriptor*)bufptr;
	bufptr += USB_DT_DEVICE_SIZE;

	if((device->bLength != USB_DT_DEVICE_SIZE) \|\| (device->bDescriptorType != USB_DT_DEVICE)) {
	adb_close(fd);
	continue;
	}

	vid = __le16_to_cpu(device->idVendor);
	pid = __le16_to_cpu(device->idProduct);
	pid = devdesc[10] \| (devdesc[11] << 8);
	DBGX("[ %s is V:%04x P:%04x ]\n", devname, vid, pid);

	// should have config descriptor next
	config = (struct usb_config_descriptor *)bufptr;
	bufptr += USB_DT_CONFIG_SIZE;
	if (config->bLength != USB_DT_CONFIG_SIZE \|\| config->bDescriptorType != USB_DT_CONFIG) {
	D("usb_config_descriptor not found\n");
	adb_close(fd);
	continue;
	}

	// loop through all the interfaces and look for the ADB interface
	interfaces = config->bNumInterfaces;
	for (i = 0; i < interfaces; i++) {
	if (bufptr + USB_DT_ENDPOINT_SIZE > devdesc + desclength)
	break;

	interface = (struct usb_interface_descriptor *)bufptr;
	bufptr += USB_DT_INTERFACE_SIZE;
	if (interface->bLength != USB_DT_INTERFACE_SIZE \|\|
	interface->bDescriptorType != USB_DT_INTERFACE) {
	D("usb_interface_descriptor not found\n");
	break;
	}

	DBGX("bInterfaceClass: %d, bInterfaceSubClass: %d,"
	"bInterfaceProtocol: %d, bNumEndpoints: %d\n",
	interface->bInterfaceClass, interface->bInterfaceSubClass,
	interface->bInterfaceProtocol, interface->bNumEndpoints);

	if (interface->bNumEndpoints == 2 &&
	is_adb_interface(vid, pid, interface->bInterfaceClass,
	interface->bInterfaceSubClass, interface->bInterfaceProtocol)) {

	DBGX("looking for bulk endpoints\n");
	// looks like ADB...
	ep1 = (struct usb_endpoint_descriptor *)bufptr;
	bufptr += USB_DT_ENDPOINT_SIZE;
	ep2 = (struct usb_endpoint_descriptor *)bufptr;
	bufptr += USB_DT_ENDPOINT_SIZE;

	if (bufptr > devdesc + desclength \|\|
	ep1->bLength != USB_DT_ENDPOINT_SIZE \|\|
	ep1->bDescriptorType != USB_DT_ENDPOINT \|\|
	ep2->bLength != USB_DT_ENDPOINT_SIZE \|\|
	ep2->bDescriptorType != USB_DT_ENDPOINT) {
	D("endpoints not found\n");
	break;
	}

	// both endpoints should be bulk
	if (ep1->bmAttributes != USB_ENDPOINT_XFER_BULK \|\|
	ep2->bmAttributes != USB_ENDPOINT_XFER_BULK) {
	D("bulk endpoints not found\n");
	continue;
	}

	/* aproto 01 needs 0 termination */
	if(interface->bInterfaceProtocol == 0x01) {
	zero_mask = ep1->wMaxPacketSize - 1;
	}

	// we have a match. now we just need to figure out which is in and which is out.
	if (ep1->bEndpointAddress & USB_ENDPOINT_DIR_MASK) {
	local_ep_in = ep1->bEndpointAddress;
	local_ep_out = ep2->bEndpointAddress;
	} else {
	local_ep_in = ep2->bEndpointAddress;
	local_ep_out = ep1->bEndpointAddress;
	}

	// read the device's serial number
	serial[0] = 0;
	memset(serial, 0, sizeof(serial));
	if (device->iSerialNumber) {
	struct usbdevfs_ctrltransfer ctrl;
	__u16 buffer[128];
	int result;

	memset(buffer, 0, sizeof(buffer));
	memset(&ctrl, 0, sizeof(ctrl));

	ctrl.bRequestType = USB_DIR_IN\|USB_TYPE_STANDARD\|USB_RECIP_DEVICE;
	ctrl.bRequest = USB_REQ_GET_DESCRIPTOR;
	ctrl.wValue = (USB_DT_STRING << 8) \| device->iSerialNumber;
	ctrl.wIndex = 0;
	ctrl.wLength = sizeof(buffer);
	ctrl.data = buffer;

	result = ioctl(fd, USBDEVFS_CONTROL, &ctrl);
	if (result > 0) {
	int i;
	// skip first word, and copy the rest to the serial string, changing shorts to bytes.
	result /= 2;
	for (i = 1; i < result; i++)
	serial[i - 1] = buffer[i];
	serial[i - 1] = 0;
	}
	}

	register_device_callback(devname, local_ep_in, local_ep_out,
	interface->bInterfaceNumber, serial, zero_mask);

	found_device = 1;
	break;
	} else {
	// skip to next interface
	bufptr += (interface->bNumEndpoints * USB_DT_ENDPOINT_SIZE);
	}
	} // end of for

	adb_close(fd);
	} // end of devdir while
	closedir(devdir);
	} //end of busdir while
	closedir(busdir);

	return found_device;
	}

	void usb_cleanup()
	{
	}

	static int usb_bulk_write(usb_handle h, const void data, int len)
	{
	struct usbdevfs_urb *urb = &h->urb_out;
	int res;

	memset(urb, 0, sizeof(*urb));
	urb->type = USBDEVFS_URB_TYPE_BULK;
	urb->endpoint = h->ep_out;
	urb->status = -1;
	urb->buffer = (void*) data;
	urb->buffer_length = len;

	D("++ write ++\n");

	adb_mutex_lock(&h->lock);
	if(h->dead) {
	res = -1;
	goto fail;
	}
	do {
	res = ioctl(h->desc, USBDEVFS_SUBMITURB, urb);
	} while((res < 0) && (errno == EINTR));

	if(res < 0) {
	goto fail;
	}

	res = -1;
	h->urb_out_busy = 1;
	for(;;) {
	adb_cond_wait(&h->notify, &h->lock);
	if(h->dead) {
	break;
	}
	if(h->urb_out_busy == 0) {
	if(urb->status == 0) {
	res = urb->actual_length;
	}
	break;
	}
	}
	fail:
	adb_mutex_unlock(&h->lock);
	D("-- write --\n");
	return res;
	}

	static int usb_bulk_read(usb_handle h, void data, int len)
	{
	struct usbdevfs_urb *urb = &h->urb_in;
	struct usbdevfs_urb *out = NULL;
	int res;

	memset(urb, 0, sizeof(*urb));
	urb->type = USBDEVFS_URB_TYPE_BULK;
	urb->endpoint = h->ep_in;
	urb->status = -1;
	urb->buffer = data;
	urb->buffer_length = len;


	adb_mutex_lock(&h->lock);
	if(h->dead) {
	res = -1;
	goto fail;
	}
	do {
	res = ioctl(h->desc, USBDEVFS_SUBMITURB, urb);
	} while((res < 0) && (errno == EINTR));

	if(res < 0) {
	goto fail;
	}

	h->urb_in_busy = 1;
	for(;;) {
	D("[ reap urb - wait ]\n");
	h->reaper_thread = pthread_self();
	adb_mutex_unlock(&h->lock);
	res = ioctl(h->desc, USBDEVFS_REAPURB, &out);
	adb_mutex_lock(&h->lock);
	h->reaper_thread = 0;
	if(h->dead) {
	res = -1;
	break;
	}
	if(res < 0) {
	if(errno == EINTR) {
	continue;
	}
	D("[ reap urb - error ]\n");
	break;
	}
	D("[ urb @%p status = %d, actual = %d ]\n",
	out, out->status, out->actual_length);

	if(out == &h->urb_in) {
	D("[ reap urb - IN complete ]\n");
	h->urb_in_busy = 0;
	if(urb->status == 0) {
	res = urb->actual_length;
	} else {
	res = -1;
	}
	break;
	}
	if(out == &h->urb_out) {
	D("[ reap urb - OUT compelete ]\n");
	h->urb_out_busy = 0;
	adb_cond_broadcast(&h->notify);
	}
	}
	fail:
	adb_mutex_unlock(&h->lock);
	return res;
	}


	int usb_write(usb_handle h, const void _data, int len)
	{
	unsigned char data = (unsigned char) _data;
	int n;
	int need_zero = 0;

	if(h->zero_mask) {
	/* if we need 0-markers and our transfer
	** is an even multiple of the packet size,
	** we make note of it
	*/
	if(!(len & h->zero_mask)) {
	need_zero = 1;
	}
	}

	while(len > 0) {
	int xfer = (len > 4096) ? 4096 : len;

	n = usb_bulk_write(h, data, xfer);
	if(n != xfer) {
	D("ERROR: n = %d, errno = %d (%s)\n",
	n, errno, strerror(errno));
	return -1;
	}

	len -= xfer;
	data += xfer;
	}

	if(need_zero){
	n = usb_bulk_write(h, _data, 0);
	return n;
	}

	return 0;
	}

	int usb_read(usb_handle h, void _data, int len)
	{
	unsigned char data = (unsigned char) _data;
	int n;

	D("++ usb_read ++\n");
	while(len > 0) {
	int xfer = (len > 4096) ? 4096 : len;

	D("[ usb read %d fd = %d], fname=%s\n", xfer, h->desc, h->fname);
	n = usb_bulk_read(h, data, xfer);
	D("[ usb read %d ] = %d, fname=%s\n", xfer, n, h->fname);
	if(n != xfer) {
	if((errno == ETIMEDOUT) && (h->desc != -1)) {
	D("[ timeout ]\n");
	if(n > 0){
	data += n;
	len -= n;
	}
	continue;
	}
	D("ERROR: n = %d, errno = %d (%s)\n",
	n, errno, strerror(errno));
	return -1;
	}

	len -= xfer;
	data += xfer;
	}

	D("-- usb_read --\n");
	return 0;
	}

	void usb_kick(usb_handle *h)
	{
	D("[ kicking %p (fd = %d) ]\n", h, h->desc);
	adb_mutex_lock(&h->lock);
	if(h->dead == 0) {
	h->dead = 1;

	/* HACK ALERT!
	** Sometimes we get stuck in ioctl(USBDEVFS_REAPURB).
	** This is a workaround for that problem.
	*/
	if (h->reaper_thread) {
	pthread_kill(h->reaper_thread, SIGALRM);
	}

	/* cancel any pending transactions
	** these will quietly fail if the txns are not active,
	** but this ensures that a reader blocked on REAPURB
	** will get unblocked
	*/
	ioctl(h->desc, USBDEVFS_DISCARDURB, &h->urb_in);
	ioctl(h->desc, USBDEVFS_DISCARDURB, &h->urb_out);
	h->urb_in.status = -ENODEV;
	h->urb_out.status = -ENODEV;
	h->urb_in_busy = 0;
	h->urb_out_busy = 0;
	adb_cond_broadcast(&h->notify);
	}
	adb_mutex_unlock(&h->lock);
	}

	int usb_close(usb_handle *h)
	{
	D("[ usb close ... ]\n");
	adb_mutex_lock(&usb_lock);
	h->next->prev = h->prev;
	h->prev->next = h->next;
	h->prev = 0;
	h->next = 0;

	adb_close(h->desc);
	D("[ usb closed %p (fd = %d) ]\n", h, h->desc);
	adb_mutex_unlock(&usb_lock);

	free(h);
	return 0;
	}

	static void register_device(const char *dev_name,
	unsigned char ep_in, unsigned char ep_out,
	int interface,
	const char *serial, unsigned zero_mask)
	{
	usb_handle* usb = 0;
	int n = 0;

	/* Since Linux will not reassign the device ID (and dev_name)
	** as long as the device is open, we can add to the list here
	** once we open it and remove from the list when we're finally
	** closed and everything will work out fine.
	**
	** If we have a usb_handle on the list 'o handles with a matching
	** name, we have no further work to do.
	*/
	adb_mutex_lock(&usb_lock);
	for(usb = handle_list.next; usb != &handle_list; usb = usb->next){
	if(!strcmp(usb->fname, dev_name)) {
	adb_mutex_unlock(&usb_lock);
	return;
	}
	}
	adb_mutex_unlock(&usb_lock);

	D("[ usb located new device %s (%d/%d/%d) ]\n",
	dev_name, ep_in, ep_out, interface);
	usb = calloc(1, sizeof(usb_handle));
	strcpy(usb->fname, dev_name);
	usb->ep_in = ep_in;
	usb->ep_out = ep_out;
	usb->zero_mask = zero_mask;

	adb_cond_init(&usb->notify, 0);
	adb_mutex_init(&usb->lock, 0);
	/* initialize mark to 1 so we don't get garbage collected after the device scan */
	usb->mark = 1;
	usb->reaper_thread = 0;

	usb->desc = unix_open(usb->fname, O_RDWR);
	if(usb->desc < 0) goto fail;
	D("[ usb open %s fd = %d]\n", usb->fname, usb->desc);
	n = ioctl(usb->desc, USBDEVFS_CLAIMINTERFACE, &interface);
	if(n != 0) goto fail;

	/* add to the end of the active handles */
	adb_mutex_lock(&usb_lock);
	usb->next = &handle_list;
	usb->prev = handle_list.prev;
	usb->prev->next = usb;
	usb->next->prev = usb;
	adb_mutex_unlock(&usb_lock);

	register_usb_transport(usb, serial);
	return;

	fail:
	D("[ usb open %s error=%d, err_str = %s]\n",
	usb->fname, errno, strerror(errno));
	if(usb->desc >= 0) {
	adb_close(usb->desc);
	}
	free(usb);
	}

	void* device_poll_thread(void* unused)
	{
	D("Created device thread\n");
	for(;;) {
	/* XXX use inotify */
	find_usb_device("/dev/bus/usb", register_device);
	kick_disconnected_devices();
	sleep(1);
	}
	return NULL;
	}

	static void sigalrm_handler(int signo)
	{
	// don't need to do anything here
	}

	void usb_init()
	{
	adb_thread_t tid;
	struct sigaction actions;

	memset(&actions, 0, sizeof(actions));
	sigemptyset(&actions.sa_mask);
	actions.sa_flags = 0;
	actions.sa_handler = sigalrm_handler;
	sigaction(SIGALRM,& actions, NULL);

	if(adb_thread_create(&tid, device_poll_thread, NULL)){
	fatal_errno("cannot create input thread");
	}
	}