auto import from //depot/cupcake/@135843
diff --git a/adb/usb_linux_client.c b/adb/usb_linux_client.c
new file mode 100644
index 0000000..530bd04
--- /dev/null
+++ b/adb/usb_linux_client.c
@@ -0,0 +1,156 @@
+/*
+ * 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 <errno.h>
+
+#include "sysdeps.h"
+
+#define TRACE_TAG TRACE_USB
+#include "adb.h"
+
+
+struct usb_handle
+{
+ int fd;
+ adb_cond_t notify;
+ adb_mutex_t lock;
+};
+
+void usb_cleanup()
+{
+ // nothing to do here
+}
+
+static void *usb_open_thread(void *x)
+{
+ struct usb_handle *usb = (struct usb_handle *)x;
+ int fd;
+
+ while (1) {
+ // wait until the USB device needs opening
+ adb_mutex_lock(&usb->lock);
+ while (usb->fd != -1)
+ adb_cond_wait(&usb->notify, &usb->lock);
+ adb_mutex_unlock(&usb->lock);
+
+ D("[ usb_thread - opening device ]\n");
+ do {
+ /* XXX use inotify? */
+ fd = unix_open("/dev/android_adb", O_RDWR);
+ if (fd < 0) {
+ // to support older kernels
+ fd = unix_open("/dev/android", O_RDWR);
+ }
+ if (fd < 0) {
+ adb_sleep_ms(1000);
+ }
+ } while (fd < 0);
+ D("[ opening device succeeded ]\n");
+
+ close_on_exec(fd);
+ usb->fd = fd;
+
+ D("[ usb_thread - registering device ]\n");
+ register_usb_transport(usb, 0);
+ }
+
+ // never gets here
+ return 0;
+}
+
+int usb_write(usb_handle *h, const void *data, int len)
+{
+ int n;
+
+ D("[ write %d ]\n", len);
+ n = adb_write(h->fd, data, len);
+ if(n != len) {
+ D("ERROR: n = %d, errno = %d (%s)\n",
+ n, errno, strerror(errno));
+ return -1;
+ }
+ D("[ done ]\n");
+ return 0;
+}
+
+int usb_read(usb_handle *h, void *data, int len)
+{
+ int n;
+
+ D("[ read %d ]\n", len);
+ n = adb_read(h->fd, data, len);
+ if(n != len) {
+ D("ERROR: n = %d, errno = %d (%s)\n",
+ n, errno, strerror(errno));
+ return -1;
+ }
+ return 0;
+}
+
+void usb_init()
+{
+ usb_handle *h;
+ adb_thread_t tid;
+ int fd;
+
+ h = calloc(1, sizeof(usb_handle));
+ h->fd = -1;
+ adb_cond_init(&h->notify, 0);
+ adb_mutex_init(&h->lock, 0);
+
+ // Open the file /dev/android_adb_enable to trigger
+ // the enabling of the adb USB function in the kernel.
+ // We never touch this file again - just leave it open
+ // indefinitely so the kernel will know when we are running
+ // and when we are not.
+ fd = unix_open("/dev/android_adb_enable", O_RDWR);
+ if (fd < 0) {
+ D("failed to open /dev/android_adb_enable\n");
+ } else {
+ close_on_exec(fd);
+ }
+
+ D("[ usb_init - starting thread ]\n");
+ if(adb_thread_create(&tid, usb_open_thread, h)){
+ fatal_errno("cannot create usb thread");
+ }
+}
+
+void usb_kick(usb_handle *h)
+{
+ D("usb_kick\n");
+ adb_mutex_lock(&h->lock);
+ adb_close(h->fd);
+ h->fd = -1;
+
+ // notify usb_open_thread that we are disconnected
+ adb_cond_signal(&h->notify);
+ adb_mutex_unlock(&h->lock);
+}
+
+int usb_close(usb_handle *h)
+{
+ // nothing to do here
+ return 0;
+}