| /* -*- Mode: C; indent-tabs-mode:t ; c-basic-offset:8 -*- */ |
| /* |
| * Hotplug functions for libusbx |
| * 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 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 hotplug Device hotplug event notification |
| * |
| * \section intro Introduction |
| * |
| * Version 1.0.16, \ref LIBUSBX_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 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. |
| * |
| * 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 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 libusbx function that takes a libusb_device. On the other hand, |
| * 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 |
| 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 *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, &handle); |
| if (LIBUSB_SUCCESS != rc) { |
| printf("Could not open USB device\n"); |
| } |
| } else if (LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT == event) { |
| if (handle) { |
| libusb_close(handle); |
| handle = NULL; |
| } |
| } else { |
| printf("Unhandled event %d\n", event); |
| } |
| count++; |
| |
| return 0; |
| } |
| |
| int main (void) { |
| libusb_hotplug_callback_handle 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, |
| &handle); |
| if (LIBUSB_SUCCESS != rc) { |
| printf("Error creating a hotplug callback\n"); |
| libusb_exit(NULL); |
| return EXIT_FAILURE; |
| } |
| |
| while (count < 2) { |
| usleep(10000); |
| } |
| |
| libusb_hotplug_deregister_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) |
| { |
| /* Handle lazy deregistration of callback */ |
| if (hotplug_cb->needs_free) { |
| /* Free callback */ |
| return 1; |
| } |
| |
| if (!(hotplug_cb->events & event)) { |
| return 0; |
| } |
| |
| if (LIBUSB_HOTPLUG_MATCH_ANY != hotplug_cb->vendor_id && |
| hotplug_cb->vendor_id != dev->device_descriptor.idVendor) { |
| return 0; |
| } |
| |
| if (LIBUSB_HOTPLUG_MATCH_ANY != hotplug_cb->product_id && |
| hotplug_cb->product_id != dev->device_descriptor.idProduct) { |
| return 0; |
| } |
| |
| if (LIBUSB_HOTPLUG_MATCH_ANY != hotplug_cb->dev_class && |
| hotplug_cb->dev_class != dev->device_descriptor.bDeviceClass) { |
| return 0; |
| } |
| |
| return hotplug_cb->cb (ctx == usbi_default_context ? NULL : 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) { |
| 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); |
| |
| /* loop through and disconnect all open handles for this device */ |
| if (LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT == event) { |
| struct libusb_device_handle *handle; |
| |
| usbi_mutex_lock(&ctx->open_devs_lock); |
| list_for_each_entry(handle, &ctx->open_devs, list, struct libusb_device_handle) { |
| if (dev == handle->dev) { |
| usbi_handle_disconnect (handle); |
| } |
| } |
| usbi_mutex_unlock(&ctx->open_devs_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 *handle) |
| { |
| libusb_hotplug_callback *new_callback; |
| static int handle_id = 1; |
| |
| /* check for hotplug support */ |
| if (!libusb_has_capability(LIBUSB_CAP_HAS_HOTPLUG)) { |
| return LIBUSB_ERROR_NOT_SUPPORTED; |
| } |
| |
| /* check for sane values */ |
| if ((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; |
| } |
| |
| USBI_GET_CONTEXT(ctx); |
| |
| new_callback = (libusb_hotplug_callback *)calloc(1, sizeof (*new_callback)); |
| if (!new_callback) { |
| return LIBUSB_ERROR_NO_MEM; |
| } |
| |
| new_callback->ctx = ctx; |
| new_callback->vendor_id = vendor_id; |
| new_callback->product_id = product_id; |
| new_callback->dev_class = dev_class; |
| new_callback->flags = flags; |
| new_callback->events = events; |
| new_callback->cb = cb_fn; |
| new_callback->user_data = user_data; |
| new_callback->needs_free = 0; |
| |
| usbi_mutex_lock(&ctx->hotplug_cbs_lock); |
| |
| /* protect the handle by the context hotplug lock. it doesn't matter if the same handle |
| * is used for different contexts only that the handle is unique for this context */ |
| new_callback->handle = handle_id++; |
| |
| list_add(&new_callback->list, &ctx->hotplug_cbs); |
| |
| if (flags & LIBUSB_HOTPLUG_ENUMERATE) { |
| struct libusb_device *dev; |
| |
| usbi_mutex_lock(&ctx->usb_devs_lock); |
| |
| list_for_each_entry(dev, &ctx->usb_devs, list, struct libusb_device) { |
| (void) usbi_hotplug_match_cb (ctx, dev, LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED, new_callback); |
| } |
| |
| usbi_mutex_unlock(&ctx->usb_devs_lock); |
| } |
| |
| usbi_mutex_unlock(&ctx->hotplug_cbs_lock); |
| |
| if (handle) { |
| *handle = new_callback->handle; |
| } |
| |
| return LIBUSB_SUCCESS; |
| } |
| |
| void API_EXPORTED libusb_hotplug_deregister_callback (struct libusb_context *ctx, |
| libusb_hotplug_callback_handle handle) |
| { |
| struct libusb_hotplug_callback *hotplug_cb; |
| libusb_hotplug_message message; |
| ssize_t ret; |
| |
| /* check for hotplug support */ |
| if (!libusb_has_capability(LIBUSB_CAP_HAS_HOTPLUG)) { |
| return; |
| } |
| |
| USBI_GET_CONTEXT(ctx); |
| |
| usbi_mutex_lock(&ctx->hotplug_cbs_lock); |
| list_for_each_entry(hotplug_cb, &ctx->hotplug_cbs, list, |
| struct libusb_hotplug_callback) { |
| if (handle == hotplug_cb->handle) { |
| /* Mark this callback for deregistration */ |
| hotplug_cb->needs_free = 1; |
| } |
| } |
| usbi_mutex_unlock(&ctx->hotplug_cbs_lock); |
| |
| /* wakeup handle_events to do the actual free */ |
| memset(&message, 0, sizeof(message)); |
| ret = usbi_write(ctx->hotplug_pipe[1], &message, sizeof(message)); |
| if (sizeof(message) != ret) { |
| usbi_err(ctx, "error writing hotplug message"); |
| } |
| } |
| |
| void usbi_hotplug_deregister_all(struct libusb_context *ctx) { |
| 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) { |
| list_del(&hotplug_cb->list); |
| free(hotplug_cb); |
| } |
| |
| usbi_mutex_unlock(&ctx->hotplug_cbs_lock); |
| } |