--- /dev/null
+/* -*- Mode: C; indent-tabs-mode:t ; c-basic-offset:8 -*- */
+/*
+ * Hotplug functions for libusb
+ * Copyright © 2012-2013 Nathan Hjelm <hjelmn@mac.com>
+ * Copyright © 2012-2013 Peter Stuge <peter@stuge.se>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <config.h>
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#ifdef HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+#include <assert.h>
+
+#include "libusbi.h"
+#include "hotplug.h"
+
+/**
+ * @defgroup libusb_hotplug Device hotplug event notification
+ * This page details how to use the libusb hotplug interface, where available.
+ *
+ * Be mindful that not all platforms currently implement hotplug notification and
+ * that you should first call on \ref libusb_has_capability() with parameter
+ * \ref LIBUSB_CAP_HAS_HOTPLUG to confirm that hotplug support is available.
+ *
+ * \page libusb_hotplug Device hotplug event notification
+ *
+ * \section hotplug_intro Introduction
+ *
+ * Version 1.0.16, \ref LIBUSB_API_VERSION >= 0x01000102, has added support
+ * for hotplug events on <b>some</b> platforms (you should test if your platform
+ * supports hotplug notification by calling \ref libusb_has_capability() with
+ * parameter \ref LIBUSB_CAP_HAS_HOTPLUG).
+ *
+ * This interface allows you to request notification for the arrival and departure
+ * of matching USB devices.
+ *
+ * To receive hotplug notification you register a callback by calling
+ * \ref libusb_hotplug_register_callback(). This function will optionally return
+ * a callback handle that can be passed to \ref libusb_hotplug_deregister_callback().
+ *
+ * A callback function must return an int (0 or 1) indicating whether the callback is
+ * expecting additional events. Returning 0 will rearm the callback and 1 will cause
+ * the callback to be deregistered. Note that when callbacks are called from
+ * libusb_hotplug_register_callback() because of the \ref LIBUSB_HOTPLUG_ENUMERATE
+ * flag, the callback return value is ignored, iow you cannot cause a callback
+ * to be deregistered by returning 1 when it is called from
+ * libusb_hotplug_register_callback().
+ *
+ * Callbacks for a particular context are automatically deregistered by libusb_exit().
+ *
+ * As of 1.0.16 there are two supported hotplug events:
+ * - LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED: A device has arrived and is ready to use
+ * - LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT: A device has left and is no longer available
+ *
+ * A hotplug event can listen for either or both of these events.
+ *
+ * Note: If you receive notification that a device has left and you have any
+ * a libusb_device_handles for the device it is up to you to call libusb_close()
+ * on each device handle to free up any remaining resources associated with the device.
+ * Once a device has left any libusb_device_handle associated with the device
+ * are invalid and will remain so even if the device comes back.
+ *
+ * When handling a LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED event it is considered
+ * safe to call any libusb function that takes a libusb_device. It also safe to
+ * open a device and submit asynchronous transfers. However, most other functions
+ * that take a libusb_device_handle are <b>not</b> safe to call. Examples of such
+ * functions are any of the \ref libusb_syncio "synchronous API" functions or the blocking
+ * functions that retrieve various \ref libusb_desc "USB descriptors". These functions must
+ * be used outside of the context of the hotplug callback.
+ *
+ * When handling a LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT event the only safe function
+ * is libusb_get_device_descriptor().
+ *
+ * The following code provides an example of the usage of the hotplug interface:
+\code
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <libusb.h>
+
+static int count = 0;
+
+int hotplug_callback(struct libusb_context *ctx, struct libusb_device *dev,
+ libusb_hotplug_event event, void *user_data) {
+ static libusb_device_handle *dev_handle = NULL;
+ struct libusb_device_descriptor desc;
+ int rc;
+
+ (void)libusb_get_device_descriptor(dev, &desc);
+
+ if (LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED == event) {
+ rc = libusb_open(dev, &dev_handle);
+ if (LIBUSB_SUCCESS != rc) {
+ printf("Could not open USB device\n");
+ }
+ } else if (LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT == event) {
+ if (dev_handle) {
+ libusb_close(dev_handle);
+ dev_handle = NULL;
+ }
+ } else {
+ printf("Unhandled event %d\n", event);
+ }
+ count++;
+
+ return 0;
+}
+
+int main (void) {
+ libusb_hotplug_callback_handle callback_handle;
+ int rc;
+
+ libusb_init(NULL);
+
+ rc = libusb_hotplug_register_callback(NULL, LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED |
+ LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT, 0, 0x045a, 0x5005,
+ LIBUSB_HOTPLUG_MATCH_ANY, hotplug_callback, NULL,
+ &callback_handle);
+ if (LIBUSB_SUCCESS != rc) {
+ printf("Error creating a hotplug callback\n");
+ libusb_exit(NULL);
+ return EXIT_FAILURE;
+ }
+
+ while (count < 2) {
+ libusb_handle_events_completed(NULL, NULL);
+ nanosleep(&(struct timespec){0, 10000000UL}, NULL);
+ }
+
+ libusb_hotplug_deregister_callback(NULL, callback_handle);
+ libusb_exit(NULL);
+
+ return 0;
+}
+\endcode
+ */
+
+static int usbi_hotplug_match_cb(struct libusb_context *ctx,
+ struct libusb_device *dev, libusb_hotplug_event event,
+ struct libusb_hotplug_callback *hotplug_cb)
+{
+ if (!(hotplug_cb->flags & event)) {
+ return 0;
+ }
+
+ if ((hotplug_cb->flags & USBI_HOTPLUG_VENDOR_ID_VALID) &&
+ hotplug_cb->vendor_id != dev->device_descriptor.idVendor) {
+ return 0;
+ }
+
+ if ((hotplug_cb->flags & USBI_HOTPLUG_PRODUCT_ID_VALID) &&
+ hotplug_cb->product_id != dev->device_descriptor.idProduct) {
+ return 0;
+ }
+
+ if ((hotplug_cb->flags & USBI_HOTPLUG_DEV_CLASS_VALID) &&
+ hotplug_cb->dev_class != dev->device_descriptor.bDeviceClass) {
+ return 0;
+ }
+
+ return hotplug_cb->cb(ctx, dev, event, hotplug_cb->user_data);
+}
+
+void usbi_hotplug_match(struct libusb_context *ctx, struct libusb_device *dev,
+ libusb_hotplug_event event)
+{
+ struct libusb_hotplug_callback *hotplug_cb, *next;
+ int ret;
+
+ usbi_mutex_lock(&ctx->hotplug_cbs_lock);
+
+ list_for_each_entry_safe(hotplug_cb, next, &ctx->hotplug_cbs, list, struct libusb_hotplug_callback) {
+ if (hotplug_cb->flags & USBI_HOTPLUG_NEEDS_FREE) {
+ /* process deregistration in usbi_hotplug_deregister() */
+ continue;
+ }
+
+ usbi_mutex_unlock(&ctx->hotplug_cbs_lock);
+ ret = usbi_hotplug_match_cb(ctx, dev, event, hotplug_cb);
+ usbi_mutex_lock(&ctx->hotplug_cbs_lock);
+
+ if (ret) {
+ list_del(&hotplug_cb->list);
+ free(hotplug_cb);
+ }
+ }
+
+ usbi_mutex_unlock(&ctx->hotplug_cbs_lock);
+}
+
+void usbi_hotplug_notification(struct libusb_context *ctx, struct libusb_device *dev,
+ libusb_hotplug_event event)
+{
+ int pending_events;
+ struct libusb_hotplug_message *message = calloc(1, sizeof(*message));
+
+ if (!message) {
+ usbi_err(ctx, "error allocating hotplug message");
+ return;
+ }
+
+ message->event = event;
+ message->device = dev;
+
+ /* Take the event data lock and add this message to the list.
+ * Only signal an event if there are no prior pending events. */
+ usbi_mutex_lock(&ctx->event_data_lock);
+ pending_events = usbi_pending_events(ctx);
+ list_add_tail(&message->list, &ctx->hotplug_msgs);
+ if (!pending_events)
+ usbi_signal_event(ctx);
+ usbi_mutex_unlock(&ctx->event_data_lock);
+}
+
+int API_EXPORTED libusb_hotplug_register_callback(libusb_context *ctx,
+ libusb_hotplug_event events, libusb_hotplug_flag flags,
+ int vendor_id, int product_id, int dev_class,
+ libusb_hotplug_callback_fn cb_fn, void *user_data,
+ libusb_hotplug_callback_handle *callback_handle)
+{
+ struct libusb_hotplug_callback *new_callback;
+
+ /* check for sane values */
+ if ((!events || (~(LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED | LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT) & events)) ||
+ (flags && (~LIBUSB_HOTPLUG_ENUMERATE & flags)) ||
+ (LIBUSB_HOTPLUG_MATCH_ANY != vendor_id && (~0xffff & vendor_id)) ||
+ (LIBUSB_HOTPLUG_MATCH_ANY != product_id && (~0xffff & product_id)) ||
+ (LIBUSB_HOTPLUG_MATCH_ANY != dev_class && (~0xff & dev_class)) ||
+ !cb_fn) {
+ return LIBUSB_ERROR_INVALID_PARAM;
+ }
+
+ /* check for hotplug support */
+ if (!libusb_has_capability(LIBUSB_CAP_HAS_HOTPLUG)) {
+ return LIBUSB_ERROR_NOT_SUPPORTED;
+ }
+
+ USBI_GET_CONTEXT(ctx);
+
+ new_callback = calloc(1, sizeof(*new_callback));
+ if (!new_callback) {
+ return LIBUSB_ERROR_NO_MEM;
+ }
+
+ new_callback->flags = (uint8_t)events;
+ if (LIBUSB_HOTPLUG_MATCH_ANY != vendor_id) {
+ new_callback->flags |= USBI_HOTPLUG_VENDOR_ID_VALID;
+ new_callback->vendor_id = (uint16_t)vendor_id;
+ }
+ if (LIBUSB_HOTPLUG_MATCH_ANY != product_id) {
+ new_callback->flags |= USBI_HOTPLUG_PRODUCT_ID_VALID;
+ new_callback->product_id = (uint16_t)product_id;
+ }
+ if (LIBUSB_HOTPLUG_MATCH_ANY != dev_class) {
+ new_callback->flags |= USBI_HOTPLUG_DEV_CLASS_VALID;
+ new_callback->dev_class = (uint8_t)dev_class;
+ }
+ new_callback->cb = cb_fn;
+ new_callback->user_data = user_data;
+
+ usbi_mutex_lock(&ctx->hotplug_cbs_lock);
+
+ /* protect the handle by the context hotplug lock */
+ new_callback->handle = ctx->next_hotplug_cb_handle++;
+
+ /* handle the unlikely case of overflow */
+ if (ctx->next_hotplug_cb_handle < 0)
+ ctx->next_hotplug_cb_handle = 1;
+
+ list_add(&new_callback->list, &ctx->hotplug_cbs);
+
+ usbi_mutex_unlock(&ctx->hotplug_cbs_lock);
+
+ usbi_dbg("new hotplug cb %p with handle %d", new_callback, new_callback->handle);
+
+ if ((flags & LIBUSB_HOTPLUG_ENUMERATE) && (events & LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED)) {
+ ssize_t i, len;
+ struct libusb_device **devs;
+
+ len = libusb_get_device_list(ctx, &devs);
+ if (len < 0) {
+ libusb_hotplug_deregister_callback(ctx,
+ new_callback->handle);
+ return (int)len;
+ }
+
+ for (i = 0; i < len; i++) {
+ usbi_hotplug_match_cb(ctx, devs[i],
+ LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED,
+ new_callback);
+ }
+
+ libusb_free_device_list(devs, 1);
+ }
+
+
+ if (callback_handle)
+ *callback_handle = new_callback->handle;
+
+ return LIBUSB_SUCCESS;
+}
+
+void API_EXPORTED libusb_hotplug_deregister_callback(struct libusb_context *ctx,
+ libusb_hotplug_callback_handle callback_handle)
+{
+ struct libusb_hotplug_callback *hotplug_cb;
+ int deregistered = 0;
+
+ /* check for hotplug support */
+ if (!libusb_has_capability(LIBUSB_CAP_HAS_HOTPLUG)) {
+ return;
+ }
+
+ USBI_GET_CONTEXT(ctx);
+
+ usbi_dbg("deregister hotplug cb %d", callback_handle);
+
+ usbi_mutex_lock(&ctx->hotplug_cbs_lock);
+ list_for_each_entry(hotplug_cb, &ctx->hotplug_cbs, list, struct libusb_hotplug_callback) {
+ if (callback_handle == hotplug_cb->handle) {
+ /* Mark this callback for deregistration */
+ hotplug_cb->flags |= USBI_HOTPLUG_NEEDS_FREE;
+ deregistered = 1;
+ }
+ }
+ usbi_mutex_unlock(&ctx->hotplug_cbs_lock);
+
+ if (deregistered) {
+ int pending_events;
+
+ usbi_mutex_lock(&ctx->event_data_lock);
+ pending_events = usbi_pending_events(ctx);
+ ctx->event_flags |= USBI_EVENT_HOTPLUG_CB_DEREGISTERED;
+ if (!pending_events)
+ usbi_signal_event(ctx);
+ usbi_mutex_unlock(&ctx->event_data_lock);
+ }
+}
+
+void usbi_hotplug_deregister(struct libusb_context *ctx, int forced)
+{
+ struct libusb_hotplug_callback *hotplug_cb, *next;
+
+ usbi_mutex_lock(&ctx->hotplug_cbs_lock);
+ list_for_each_entry_safe(hotplug_cb, next, &ctx->hotplug_cbs, list, struct libusb_hotplug_callback) {
+ if (forced || (hotplug_cb->flags & USBI_HOTPLUG_NEEDS_FREE)) {
+ usbi_dbg("freeing hotplug cb %p with handle %d", hotplug_cb,
+ hotplug_cb->handle);
+ list_del(&hotplug_cb->list);
+ free(hotplug_cb);
+ }
+ }
+ usbi_mutex_unlock(&ctx->hotplug_cbs_lock);
+}
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