adb: reorganize adbd USB handling code.

Break adbd's USB initialization code into its own static library to
allow it to be used by benchmark code that pretends to be adbd.

Bug: http://b/31289465
Test: adb shell works on bullhead
Change-Id: I0ac7d78a4f7aef59bd6d14fc5cf1ed870e1f3a9d
diff --git a/adb/daemon/usb.cpp b/adb/daemon/usb.cpp
new file mode 100644
index 0000000..a35c210
--- /dev/null
+++ b/adb/daemon/usb.cpp
@@ -0,0 +1,446 @@
+/*
+ * 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.
+ */
+
+#define TRACE_TAG USB
+
+#include "sysdeps.h"
+
+#include <dirent.h>
+#include <errno.h>
+#include <linux/usb/ch9.h>
+#include <linux/usb/functionfs.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <algorithm>
+#include <atomic>
+#include <chrono>
+#include <condition_variable>
+#include <mutex>
+#include <thread>
+
+#include <android-base/logging.h>
+#include <android-base/properties.h>
+
+#include "adb.h"
+#include "daemon/usb.h"
+#include "transport.h"
+
+using namespace std::chrono_literals;
+
+#define MAX_PACKET_SIZE_FS 64
+#define MAX_PACKET_SIZE_HS 512
+#define MAX_PACKET_SIZE_SS 1024
+
+// Writes larger than 16k fail on some devices (seed with 3.10.49-g209ea2f in particular).
+#define USB_FFS_MAX_WRITE 16384
+
+// The kernel allocates a contiguous buffer for reads, which can fail for large ones due to
+// fragmentation. 16k chosen arbitrarily to match the write limit.
+#define USB_FFS_MAX_READ 16384
+
+#define cpu_to_le16(x) htole16(x)
+#define cpu_to_le32(x) htole32(x)
+
+static int dummy_fd = -1;
+
+struct func_desc {
+    struct usb_interface_descriptor intf;
+    struct usb_endpoint_descriptor_no_audio source;
+    struct usb_endpoint_descriptor_no_audio sink;
+} __attribute__((packed));
+
+struct ss_func_desc {
+    struct usb_interface_descriptor intf;
+    struct usb_endpoint_descriptor_no_audio source;
+    struct usb_ss_ep_comp_descriptor source_comp;
+    struct usb_endpoint_descriptor_no_audio sink;
+    struct usb_ss_ep_comp_descriptor sink_comp;
+} __attribute__((packed));
+
+struct desc_v1 {
+    struct usb_functionfs_descs_head_v1 {
+        __le32 magic;
+        __le32 length;
+        __le32 fs_count;
+        __le32 hs_count;
+    } __attribute__((packed)) header;
+    struct func_desc fs_descs, hs_descs;
+} __attribute__((packed));
+
+struct desc_v2 {
+    struct usb_functionfs_descs_head_v2 header;
+    // The rest of the structure depends on the flags in the header.
+    __le32 fs_count;
+    __le32 hs_count;
+    __le32 ss_count;
+    __le32 os_count;
+    struct func_desc fs_descs, hs_descs;
+    struct ss_func_desc ss_descs;
+    struct usb_os_desc_header os_header;
+    struct usb_ext_compat_desc os_desc;
+} __attribute__((packed));
+
+static struct func_desc fs_descriptors = {
+    .intf = {
+        .bLength = sizeof(fs_descriptors.intf),
+        .bDescriptorType = USB_DT_INTERFACE,
+        .bInterfaceNumber = 0,
+        .bNumEndpoints = 2,
+        .bInterfaceClass = ADB_CLASS,
+        .bInterfaceSubClass = ADB_SUBCLASS,
+        .bInterfaceProtocol = ADB_PROTOCOL,
+        .iInterface = 1, /* first string from the provided table */
+    },
+    .source = {
+        .bLength = sizeof(fs_descriptors.source),
+        .bDescriptorType = USB_DT_ENDPOINT,
+        .bEndpointAddress = 1 | USB_DIR_OUT,
+        .bmAttributes = USB_ENDPOINT_XFER_BULK,
+        .wMaxPacketSize = MAX_PACKET_SIZE_FS,
+    },
+    .sink = {
+        .bLength = sizeof(fs_descriptors.sink),
+        .bDescriptorType = USB_DT_ENDPOINT,
+        .bEndpointAddress = 2 | USB_DIR_IN,
+        .bmAttributes = USB_ENDPOINT_XFER_BULK,
+        .wMaxPacketSize = MAX_PACKET_SIZE_FS,
+    },
+};
+
+static struct func_desc hs_descriptors = {
+    .intf = {
+        .bLength = sizeof(hs_descriptors.intf),
+        .bDescriptorType = USB_DT_INTERFACE,
+        .bInterfaceNumber = 0,
+        .bNumEndpoints = 2,
+        .bInterfaceClass = ADB_CLASS,
+        .bInterfaceSubClass = ADB_SUBCLASS,
+        .bInterfaceProtocol = ADB_PROTOCOL,
+        .iInterface = 1, /* first string from the provided table */
+    },
+    .source = {
+        .bLength = sizeof(hs_descriptors.source),
+        .bDescriptorType = USB_DT_ENDPOINT,
+        .bEndpointAddress = 1 | USB_DIR_OUT,
+        .bmAttributes = USB_ENDPOINT_XFER_BULK,
+        .wMaxPacketSize = MAX_PACKET_SIZE_HS,
+    },
+    .sink = {
+        .bLength = sizeof(hs_descriptors.sink),
+        .bDescriptorType = USB_DT_ENDPOINT,
+        .bEndpointAddress = 2 | USB_DIR_IN,
+        .bmAttributes = USB_ENDPOINT_XFER_BULK,
+        .wMaxPacketSize = MAX_PACKET_SIZE_HS,
+    },
+};
+
+static struct ss_func_desc ss_descriptors = {
+    .intf = {
+        .bLength = sizeof(ss_descriptors.intf),
+        .bDescriptorType = USB_DT_INTERFACE,
+        .bInterfaceNumber = 0,
+        .bNumEndpoints = 2,
+        .bInterfaceClass = ADB_CLASS,
+        .bInterfaceSubClass = ADB_SUBCLASS,
+        .bInterfaceProtocol = ADB_PROTOCOL,
+        .iInterface = 1, /* first string from the provided table */
+    },
+    .source = {
+        .bLength = sizeof(ss_descriptors.source),
+        .bDescriptorType = USB_DT_ENDPOINT,
+        .bEndpointAddress = 1 | USB_DIR_OUT,
+        .bmAttributes = USB_ENDPOINT_XFER_BULK,
+        .wMaxPacketSize = MAX_PACKET_SIZE_SS,
+    },
+    .source_comp = {
+        .bLength = sizeof(ss_descriptors.source_comp),
+        .bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
+    },
+    .sink = {
+        .bLength = sizeof(ss_descriptors.sink),
+        .bDescriptorType = USB_DT_ENDPOINT,
+        .bEndpointAddress = 2 | USB_DIR_IN,
+        .bmAttributes = USB_ENDPOINT_XFER_BULK,
+        .wMaxPacketSize = MAX_PACKET_SIZE_SS,
+    },
+    .sink_comp = {
+        .bLength = sizeof(ss_descriptors.sink_comp),
+        .bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
+    },
+};
+
+struct usb_ext_compat_desc os_desc_compat = {
+    .bFirstInterfaceNumber = 0,
+    .Reserved1 = cpu_to_le32(1),
+    .CompatibleID = {0},
+    .SubCompatibleID = {0},
+    .Reserved2 = {0},
+};
+
+static struct usb_os_desc_header os_desc_header = {
+    .interface = cpu_to_le32(1),
+    .dwLength = cpu_to_le32(sizeof(os_desc_header) + sizeof(os_desc_compat)),
+    .bcdVersion = cpu_to_le32(1),
+    .wIndex = cpu_to_le32(4),
+    .bCount = cpu_to_le32(1),
+    .Reserved = cpu_to_le32(0),
+};
+
+#define STR_INTERFACE_ "ADB Interface"
+
+static const struct {
+    struct usb_functionfs_strings_head header;
+    struct {
+        __le16 code;
+        const char str1[sizeof(STR_INTERFACE_)];
+    } __attribute__((packed)) lang0;
+} __attribute__((packed)) strings = {
+    .header = {
+        .magic = cpu_to_le32(FUNCTIONFS_STRINGS_MAGIC),
+        .length = cpu_to_le32(sizeof(strings)),
+        .str_count = cpu_to_le32(1),
+        .lang_count = cpu_to_le32(1),
+    },
+    .lang0 = {
+        cpu_to_le16(0x0409), /* en-us */
+        STR_INTERFACE_,
+    },
+};
+
+bool init_functionfs(struct usb_handle* h) {
+    ssize_t ret;
+    struct desc_v1 v1_descriptor;
+    struct desc_v2 v2_descriptor;
+
+    v2_descriptor.header.magic = cpu_to_le32(FUNCTIONFS_DESCRIPTORS_MAGIC_V2);
+    v2_descriptor.header.length = cpu_to_le32(sizeof(v2_descriptor));
+    v2_descriptor.header.flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC |
+                                 FUNCTIONFS_HAS_SS_DESC | FUNCTIONFS_HAS_MS_OS_DESC;
+    v2_descriptor.fs_count = 3;
+    v2_descriptor.hs_count = 3;
+    v2_descriptor.ss_count = 5;
+    v2_descriptor.os_count = 1;
+    v2_descriptor.fs_descs = fs_descriptors;
+    v2_descriptor.hs_descs = hs_descriptors;
+    v2_descriptor.ss_descs = ss_descriptors;
+    v2_descriptor.os_header = os_desc_header;
+    v2_descriptor.os_desc = os_desc_compat;
+
+    if (h->control < 0) { // might have already done this before
+        D("OPENING %s", USB_FFS_ADB_EP0);
+        h->control = adb_open(USB_FFS_ADB_EP0, O_RDWR);
+        if (h->control < 0) {
+            D("[ %s: cannot open control endpoint: errno=%d]", USB_FFS_ADB_EP0, errno);
+            goto err;
+        }
+
+        ret = adb_write(h->control, &v2_descriptor, sizeof(v2_descriptor));
+        if (ret < 0) {
+            v1_descriptor.header.magic = cpu_to_le32(FUNCTIONFS_DESCRIPTORS_MAGIC);
+            v1_descriptor.header.length = cpu_to_le32(sizeof(v1_descriptor));
+            v1_descriptor.header.fs_count = 3;
+            v1_descriptor.header.hs_count = 3;
+            v1_descriptor.fs_descs = fs_descriptors;
+            v1_descriptor.hs_descs = hs_descriptors;
+            D("[ %s: Switching to V1_descriptor format errno=%d ]", USB_FFS_ADB_EP0, errno);
+            ret = adb_write(h->control, &v1_descriptor, sizeof(v1_descriptor));
+            if (ret < 0) {
+                D("[ %s: write descriptors failed: errno=%d ]", USB_FFS_ADB_EP0, errno);
+                goto err;
+            }
+        }
+
+        ret = adb_write(h->control, &strings, sizeof(strings));
+        if (ret < 0) {
+            D("[ %s: writing strings failed: errno=%d]", USB_FFS_ADB_EP0, errno);
+            goto err;
+        }
+    }
+
+    h->bulk_out = adb_open(USB_FFS_ADB_OUT, O_RDWR);
+    if (h->bulk_out < 0) {
+        D("[ %s: cannot open bulk-out ep: errno=%d ]", USB_FFS_ADB_OUT, errno);
+        goto err;
+    }
+
+    h->bulk_in = adb_open(USB_FFS_ADB_IN, O_RDWR);
+    if (h->bulk_in < 0) {
+        D("[ %s: cannot open bulk-in ep: errno=%d ]", USB_FFS_ADB_IN, errno);
+        goto err;
+    }
+
+    return true;
+
+err:
+    if (h->bulk_in > 0) {
+        adb_close(h->bulk_in);
+        h->bulk_in = -1;
+    }
+    if (h->bulk_out > 0) {
+        adb_close(h->bulk_out);
+        h->bulk_out = -1;
+    }
+    if (h->control > 0) {
+        adb_close(h->control);
+        h->control = -1;
+    }
+    return false;
+}
+
+static void usb_ffs_open_thread(void* x) {
+    struct usb_handle* usb = (struct usb_handle*)x;
+
+    adb_thread_setname("usb ffs open");
+
+    while (true) {
+        // wait until the USB device needs opening
+        std::unique_lock<std::mutex> lock(usb->lock);
+        while (!usb->open_new_connection) {
+            usb->notify.wait(lock);
+        }
+        usb->open_new_connection = false;
+        lock.unlock();
+
+        while (true) {
+            if (init_functionfs(usb)) {
+                break;
+            }
+            std::this_thread::sleep_for(1s);
+        }
+        android::base::SetProperty("sys.usb.ffs.ready", "1");
+
+        D("[ usb_thread - registering device ]");
+        register_usb_transport(usb, 0, 0, 1);
+    }
+
+    // never gets here
+    abort();
+}
+
+static int usb_ffs_write(usb_handle* h, const void* data, int len) {
+    D("about to write (fd=%d, len=%d)", h->bulk_in, len);
+
+    const char* buf = static_cast<const char*>(data);
+    while (len > 0) {
+        int write_len = std::min(USB_FFS_MAX_WRITE, len);
+        int n = adb_write(h->bulk_in, buf, write_len);
+        if (n < 0) {
+            D("ERROR: fd = %d, n = %d: %s", h->bulk_in, n, strerror(errno));
+            return -1;
+        }
+        buf += n;
+        len -= n;
+    }
+
+    D("[ done fd=%d ]", h->bulk_in);
+    return 0;
+}
+
+static int usb_ffs_read(usb_handle* h, void* data, int len) {
+    D("about to read (fd=%d, len=%d)", h->bulk_out, len);
+
+    char* buf = static_cast<char*>(data);
+    while (len > 0) {
+        int read_len = std::min(USB_FFS_MAX_READ, len);
+        int n = adb_read(h->bulk_out, buf, read_len);
+        if (n < 0) {
+            D("ERROR: fd = %d, n = %d: %s", h->bulk_out, n, strerror(errno));
+            return -1;
+        }
+        buf += n;
+        len -= n;
+    }
+
+    D("[ done fd=%d ]", h->bulk_out);
+    return 0;
+}
+
+static void usb_ffs_kick(usb_handle* h) {
+    int err;
+
+    err = ioctl(h->bulk_in, FUNCTIONFS_CLEAR_HALT);
+    if (err < 0) {
+        D("[ kick: source (fd=%d) clear halt failed (%d) ]", h->bulk_in, errno);
+    }
+
+    err = ioctl(h->bulk_out, FUNCTIONFS_CLEAR_HALT);
+    if (err < 0) {
+        D("[ kick: sink (fd=%d) clear halt failed (%d) ]", h->bulk_out, errno);
+    }
+
+    // don't close ep0 here, since we may not need to reinitialize it with
+    // the same descriptors again. if however ep1/ep2 fail to re-open in
+    // init_functionfs, only then would we close and open ep0 again.
+    // Ditto the comment in usb_adb_kick.
+    h->kicked = true;
+    TEMP_FAILURE_RETRY(dup2(dummy_fd, h->bulk_out));
+    TEMP_FAILURE_RETRY(dup2(dummy_fd, h->bulk_in));
+}
+
+static void usb_ffs_close(usb_handle* h) {
+    h->kicked = false;
+    adb_close(h->bulk_out);
+    adb_close(h->bulk_in);
+    // Notify usb_adb_open_thread to open a new connection.
+    h->lock.lock();
+    h->open_new_connection = true;
+    h->lock.unlock();
+    h->notify.notify_one();
+}
+
+static void usb_ffs_init() {
+    D("[ usb_init - using FunctionFS ]");
+
+    usb_handle* h = new usb_handle();
+
+    h->write = usb_ffs_write;
+    h->read = usb_ffs_read;
+    h->kick = usb_ffs_kick;
+    h->close = usb_ffs_close;
+
+    D("[ usb_init - starting thread ]");
+    if (!adb_thread_create(usb_ffs_open_thread, h)) {
+        fatal_errno("[ cannot create usb thread ]\n");
+    }
+}
+
+void usb_init() {
+    dummy_fd = adb_open("/dev/null", O_WRONLY);
+    CHECK_NE(dummy_fd, -1);
+    usb_ffs_init();
+}
+
+int usb_write(usb_handle* h, const void* data, int len) {
+    return h->write(h, data, len);
+}
+
+int usb_read(usb_handle* h, void* data, int len) {
+    return h->read(h, data, len);
+}
+
+int usb_close(usb_handle* h) {
+    h->close(h);
+    return 0;
+}
+
+void usb_kick(usb_handle* h) {
+    h->kick(h);
+}