/* * Core functions for libusb * Copyright (C) 2007-2008 Daniel Drake <dsd@gentoo.org> * Copyright (c) 2001 Johannes Erdfelt <johannes@erdfelt.com> * * 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 <stdarg.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/types.h> #ifdef HAVE_SYS_TIME_H #include <sys/time.h> #endif #include "libusbi.h" #if defined(OS_LINUX) const struct usbi_os_backend * const usbi_backend = &linux_usbfs_backend; #elif defined(OS_DARWIN) const struct usbi_os_backend * const usbi_backend = &darwin_backend; #elif defined(OS_OPENBSD) const struct usbi_os_backend * const usbi_backend = &openbsd_backend; #elif defined(OS_WINDOWS) const struct usbi_os_backend * const usbi_backend = &windows_backend; #else #error "Unsupported OS" #endif const struct libusb_version libusb_version_internal = { LIBUSB_MAJOR, LIBUSB_MINOR, LIBUSB_MICRO, LIBUSB_NANO, LIBUSB_RC, LIBUSB_DESCRIBE }; struct libusb_context *usbi_default_context = NULL; static int default_context_refcnt = 0; static usbi_mutex_static_t default_context_lock = USBI_MUTEX_INITIALIZER; /** * \mainpage libusb-1.0 API Reference * * \section intro Introduction * * libusb is an open source library that allows you to communicate with USB * devices from userspace. For more info, see the * <a href="http://libusb.sourceforge.net">libusb homepage</a>. * * This documentation is aimed at application developers wishing to * communicate with USB peripherals from their own software. After reviewing * this documentation, feedback and questions can be sent to the * <a href="http://sourceforge.net/mail/?group_id=1674">libusb-devel mailing * list</a>. * * This documentation assumes knowledge of how to operate USB devices from * a software standpoint (descriptors, configurations, interfaces, endpoints, * control/bulk/interrupt/isochronous transfers, etc). Full information * can be found in the <a href="http://www.usb.org/developers/docs/">USB 2.0 * Specification</a> which is available for free download. You can probably * find less verbose introductions by searching the web. * * \section features Library features * * - All transfer types supported (control/bulk/interrupt/isochronous) * - 2 transfer interfaces: * -# Synchronous (simple) * -# Asynchronous (more complicated, but more powerful) * - Thread safe (although the asynchronous interface means that you * usually won't need to thread) * - Lightweight with lean API * - Compatible with libusb-0.1 through the libusb-compat-0.1 translation layer * * \section gettingstarted Getting Started * * To begin reading the API documentation, start with the Modules page which * links to the different categories of libusb's functionality. * * One decision you will have to make is whether to use the synchronous * or the asynchronous data transfer interface. The \ref io documentation * provides some insight into this topic. * * Some example programs can be found in the libusb source distribution under * the "examples" subdirectory. The libusb homepage includes a list of * real-life project examples which use libusb. * * \section errorhandling Error handling * * libusb functions typically return 0 on success or a negative error code * on failure. These negative error codes relate to LIBUSB_ERROR constants * which are listed on the \ref misc "miscellaneous" documentation page. * * \section msglog Debug message logging * * libusb does not log any messages by default. Your application is therefore * free to close stdout/stderr and those descriptors may be reused without * worry. * * The libusb_set_debug() function can be used to enable stdout/stderr logging * of certain messages. Under standard configuration, libusb doesn't really * log much at all, so you are advised to use this function to enable all * error/warning/informational messages. It will help you debug problems with * your software. * * The logged messages are unstructured. There is no one-to-one correspondence * between messages being logged and success or failure return codes from * libusb functions. There is no format to the messages, so you should not * try to capture or parse them. They are not and will not be localized. * These messages are not suitable for being passed to your application user; * instead, you should interpret the error codes returned from libusb functions * and provide appropriate notification to the user. The messages are simply * there to aid you as a programmer, and if you're confused because you're * getting a strange error code from a libusb function, enabling message * logging may give you a suitable explanation. * * The LIBUSB_DEBUG environment variable can be used to enable message logging * at run-time. This environment variable should be set to a number, which is * interpreted the same as the libusb_set_debug() parameter. When this * environment variable is set, the message logging verbosity level is fixed * and libusb_set_debug() effectively does nothing. * * libusb can be compiled without any logging functions, useful for embedded * systems. In this case, libusb_set_debug() and the LIBUSB_DEBUG environment * variable have no effects. * * libusb can also be compiled with verbose debugging messages. When the * library is compiled in this way, all messages of all verbosities are always * logged. libusb_set_debug() and the LIBUSB_DEBUG environment variable have * no effects. * * \section remarks Other remarks * * libusb does have imperfections. The \ref caveats "caveats" page attempts * to document these. */ /** * \page caveats Caveats * * \section devresets Device resets * * The libusb_reset_device() function allows you to reset a device. If your * program has to call such a function, it should obviously be aware that * the reset will cause device state to change (e.g. register values may be * reset). * * The problem is that any other program could reset the device your program * is working with, at any time. libusb does not offer a mechanism to inform * you when this has happened, so if someone else resets your device it will * not be clear to your own program why the device state has changed. * * Ultimately, this is a limitation of writing drivers in userspace. * Separation from the USB stack in the underlying kernel makes it difficult * for the operating system to deliver such notifications to your program. * The Linux kernel USB stack allows such reset notifications to be delivered * to in-kernel USB drivers, but it is not clear how such notifications could * be delivered to second-class drivers that live in userspace. * * \section blockonly Blocking-only functionality * * The functionality listed below is only available through synchronous, * blocking functions. There are no asynchronous/non-blocking alternatives, * and no clear ways of implementing these. * * - Configuration activation (libusb_set_configuration()) * - Interface/alternate setting activation (libusb_set_interface_alt_setting()) * - Releasing of interfaces (libusb_release_interface()) * - Clearing of halt/stall condition (libusb_clear_halt()) * - Device resets (libusb_reset_device()) * * \section nohotplug No hotplugging * * libusb-1.0 lacks functionality for providing notifications of when devices * are added or removed. This functionality is planned to be implemented * for libusb-1.1. * * That said, there is basic disconnection handling for open device handles: * - If there are ongoing transfers, libusb's handle_events loop will detect * disconnections and complete ongoing transfers with the * LIBUSB_TRANSFER_NO_DEVICE status code. * - Many functions such as libusb_set_configuration() return the special * LIBUSB_ERROR_NO_DEVICE error code when the device has been disconnected. * * \section configsel Configuration selection and handling * * When libusb presents a device handle to an application, there is a chance * that the corresponding device may be in unconfigured state. For devices * with multiple configurations, there is also a chance that the configuration * currently selected is not the one that the application wants to use. * * The obvious solution is to add a call to libusb_set_configuration() early * on during your device initialization routines, but there are caveats to * be aware of: * -# If the device is already in the desired configuration, calling * libusb_set_configuration() using the same configuration value will cause * a lightweight device reset. This may not be desirable behaviour. * -# libusb will be unable to change configuration if the device is in * another configuration and other programs or drivers have claimed * interfaces under that configuration. * -# In the case where the desired configuration is already active, libusb * may not even be able to perform a lightweight device reset. For example, * take my USB keyboard with fingerprint reader: I'm interested in driving * the fingerprint reader interface through libusb, but the kernel's * USB-HID driver will almost always have claimed the keyboard interface. * Because the kernel has claimed an interface, it is not even possible to * perform the lightweight device reset, so libusb_set_configuration() will * fail. (Luckily the device in question only has a single configuration.) * * One solution to some of the above problems is to consider the currently * active configuration. If the configuration we want is already active, then * we don't have to select any configuration: \code cfg = libusb_get_configuration(dev); if (cfg != desired) libusb_set_configuration(dev, desired); \endcode * * This is probably suitable for most scenarios, but is inherently racy: * another application or driver may change the selected configuration * <em>after</em> the libusb_get_configuration() call. * * Even in cases where libusb_set_configuration() succeeds, consider that other * applications or drivers may change configuration after your application * calls libusb_set_configuration(). * * One possible way to lock your device into a specific configuration is as * follows: * -# Set the desired configuration (or use the logic above to realise that * it is already in the desired configuration) * -# Claim the interface that you wish to use * -# Check that the currently active configuration is the one that you want * to use. * * The above method works because once an interface is claimed, no application * or driver is able to select another configuration. * * \section earlycomp Early transfer completion * * NOTE: This section is currently Linux-centric. I am not sure if any of these * considerations apply to Darwin or other platforms. * * When a transfer completes early (i.e. when less data is received/sent in * any one packet than the transfer buffer allows for) then libusb is designed * to terminate the transfer immediately, not transferring or receiving any * more data unless other transfers have been queued by the user. * * On legacy platforms, libusb is unable to do this in all situations. After * the incomplete packet occurs, "surplus" data may be transferred. Prior to * libusb v1.0.2, this information was lost (and for device-to-host transfers, * the corresponding data was discarded). As of libusb v1.0.3, this information * is kept (the data length of the transfer is updated) and, for device-to-host * transfers, any surplus data was added to the buffer. Still, this is not * a nice solution because it loses the information about the end of the short * packet, and the user probably wanted that surplus data to arrive in the next * logical transfer. * * A previous workaround was to only ever submit transfers of size 16kb or * less. * * As of libusb v1.0.4 and Linux v2.6.32, this is fixed. A technical * explanation of this issue follows. * * When you ask libusb to submit a bulk transfer larger than 16kb in size, * libusb breaks it up into a number of smaller subtransfers. This is because * the usbfs kernel interface only accepts transfers of up to 16kb in size. * The subtransfers are submitted all at once so that the kernel can queue * them at the hardware level, therefore maximizing bus throughput. * * On legacy platforms, this caused problems when transfers completed early. * Upon this event, the kernel would terminate all further packets in that * subtransfer (but not any following ones). libusb would note this event and * immediately cancel any following subtransfers that had been queued, * but often libusb was not fast enough, and the following subtransfers had * started before libusb got around to cancelling them. * * Thanks to an API extension to usbfs, this is fixed with recent kernel and * libusb releases. The solution was to allow libusb to communicate to the * kernel where boundaries occur between logical libusb-level transfers. When * a short transfer (or other error) occurs, the kernel will cancel all the * subtransfers until the boundary without allowing those transfers to start. * * \section zlp Zero length packets * * - libusb is able to send a packet of zero length to an endpoint simply by * submitting a transfer of zero length. On Linux, this did not work with * libusb versions prior to 1.0.3 and kernel versions prior to 2.6.31. * - The \ref libusb_transfer_flags::LIBUSB_TRANSFER_ADD_ZERO_PACKET * "LIBUSB_TRANSFER_ADD_ZERO_PACKET" flag is currently only supported on Linux. */ /** * \page contexts Contexts * * It is possible that libusb may be used simultaneously from two independent * libraries linked into the same executable. For example, if your application * has a plugin-like system which allows the user to dynamically load a range * of modules into your program, it is feasible that two independently * developed modules may both use libusb. * * libusb is written to allow for these multiple user scenarios. The two * "instances" of libusb will not interfere: libusb_set_debug() calls * from one user will not affect the same settings for other users, other * users can continue using libusb after one of them calls libusb_exit(), etc. * * This is made possible through libusb's <em>context</em> concept. When you * call libusb_init(), you are (optionally) given a context. You can then pass * this context pointer back into future libusb functions. * * In order to keep things simple for more simplistic applications, it is * legal to pass NULL to all functions requiring a context pointer (as long as * you're sure no other code will attempt to use libusb from the same process). * When you pass NULL, the default context will be used. The default context * is created the first time a process calls libusb_init() when no other * context is alive. Contexts are destroyed during libusb_exit(). * * The default context is reference-counted and can be shared. That means that * if libusb_init(NULL) is called twice within the same process, the two * users end up sharing the same context. The deinitialization and freeing of * the default context will only happen when the last user calls libusb_exit(). * In other words, the default context is created and initialized when its * reference count goes from 0 to 1, and is deinitialized and destroyed when * its reference count goes from 1 to 0. * * You may be wondering why only a subset of libusb functions require a * context pointer in their function definition. Internally, libusb stores * context pointers in other objects (e.g. libusb_device instances) and hence * can infer the context from those objects. */ /** * @defgroup lib Library initialization/deinitialization * This page details how to initialize and deinitialize libusb. Initialization * must be performed before using any libusb functionality, and similarly you * must not call any libusb functions after deinitialization. */ /** * @defgroup dev Device handling and enumeration * The functionality documented below is designed to help with the following * operations: * - Enumerating the USB devices currently attached to the system * - Choosing a device to operate from your software * - Opening and closing the chosen device * * \section nutshell In a nutshell... * * The description below really makes things sound more complicated than they * actually are. The following sequence of function calls will be suitable * for almost all scenarios and does not require you to have such a deep * understanding of the resource management issues: * \code // discover devices libusb_device **list; libusb_device *found = NULL; ssize_t cnt = libusb_get_device_list(NULL, &list); ssize_t i = 0; int err = 0; if (cnt < 0) error(); for (i = 0; i < cnt; i++) { libusb_device *device = list[i]; if (is_interesting(device)) { found = device; break; } } if (found) { libusb_device_handle *handle; err = libusb_open(found, &handle); if (err) error(); // etc } libusb_free_device_list(list, 1); \endcode * * The two important points: * - You asked libusb_free_device_list() to unreference the devices (2nd * parameter) * - You opened the device before freeing the list and unreferencing the * devices * * If you ended up with a handle, you can now proceed to perform I/O on the * device. * * \section devshandles Devices and device handles * libusb has a concept of a USB device, represented by the * \ref libusb_device opaque type. A device represents a USB device that * is currently or was previously connected to the system. Using a reference * to a device, you can determine certain information about the device (e.g. * you can read the descriptor data). * * The libusb_get_device_list() function can be used to obtain a list of * devices currently connected to the system. This is known as device * discovery. * * Just because you have a reference to a device does not mean it is * necessarily usable. The device may have been unplugged, you may not have * permission to operate such device, or another program or driver may be * using the device. * * When you've found a device that you'd like to operate, you must ask * libusb to open the device using the libusb_open() function. Assuming * success, libusb then returns you a <em>device handle</em> * (a \ref libusb_device_handle pointer). All "real" I/O operations then * operate on the handle rather than the original device pointer. * * \section devref Device discovery and reference counting * * Device discovery (i.e. calling libusb_get_device_list()) returns a * freshly-allocated list of devices. The list itself must be freed when * you are done with it. libusb also needs to know when it is OK to free * the contents of the list - the devices themselves. * * To handle these issues, libusb provides you with two separate items: * - A function to free the list itself * - A reference counting system for the devices inside * * New devices presented by the libusb_get_device_list() function all have a * reference count of 1. You can increase and decrease reference count using * libusb_ref_device() and libusb_unref_device(). A device is destroyed when * its reference count reaches 0. * * With the above information in mind, the process of opening a device can * be viewed as follows: * -# Discover devices using libusb_get_device_list(). * -# Choose the device that you want to operate, and call libusb_open(). * -# Unref all devices in the discovered device list. * -# Free the discovered device list. * * The order is important - you must not unreference the device before * attempting to open it, because unreferencing it may destroy the device. * * For convenience, the libusb_free_device_list() function includes a * parameter to optionally unreference all the devices in the list before * freeing the list itself. This combines steps 3 and 4 above. * * As an implementation detail, libusb_open() actually adds a reference to * the device in question. This is because the device remains available * through the handle via libusb_get_device(). The reference is deleted during * libusb_close(). */ /** @defgroup misc Miscellaneous */ /* we traverse usbfs without knowing how many devices we are going to find. * so we create this discovered_devs model which is similar to a linked-list * which grows when required. it can be freed once discovery has completed, * eliminating the need for a list node in the libusb_device structure * itself. */ #define DISCOVERED_DEVICES_SIZE_STEP 8 static struct discovered_devs *discovered_devs_alloc(void) { struct discovered_devs *ret = malloc(sizeof(*ret) + (sizeof(void *) * DISCOVERED_DEVICES_SIZE_STEP)); if (ret) { ret->len = 0; ret->capacity = DISCOVERED_DEVICES_SIZE_STEP; } return ret; } /* append a device to the discovered devices collection. may realloc itself, * returning new discdevs. returns NULL on realloc failure. */ struct discovered_devs *discovered_devs_append( struct discovered_devs *discdevs, struct libusb_device *dev) { size_t len = discdevs->len; size_t capacity; /* if there is space, just append the device */ if (len < discdevs->capacity) { discdevs->devices[len] = libusb_ref_device(dev); discdevs->len++; return discdevs; } /* exceeded capacity, need to grow */ usbi_dbg("need to increase capacity"); capacity = discdevs->capacity + DISCOVERED_DEVICES_SIZE_STEP; discdevs = realloc(discdevs, sizeof(*discdevs) + (sizeof(void *) * capacity)); if (discdevs) { discdevs->capacity = capacity; discdevs->devices[len] = libusb_ref_device(dev); discdevs->len++; } return discdevs; } static void discovered_devs_free(struct discovered_devs *discdevs) { size_t i; for (i = 0; i < discdevs->len; i++) libusb_unref_device(discdevs->devices[i]); free(discdevs); } /* Allocate a new device with a specific session ID. The returned device has * a reference count of 1. */ struct libusb_device *usbi_alloc_device(struct libusb_context *ctx, unsigned long session_id) { size_t priv_size = usbi_backend->device_priv_size; struct libusb_device *dev = calloc(1, sizeof(*dev) + priv_size); int r; if (!dev) return NULL; r = usbi_mutex_init(&dev->lock, NULL); if (r) { free(dev); return NULL; } dev->ctx = ctx; dev->refcnt = 1; dev->session_data = session_id; dev->speed = LIBUSB_SPEED_UNKNOWN; memset(&dev->os_priv, 0, priv_size); usbi_mutex_lock(&ctx->usb_devs_lock); list_add(&dev->list, &ctx->usb_devs); usbi_mutex_unlock(&ctx->usb_devs_lock); return dev; } /* Perform some final sanity checks on a newly discovered device. If this * function fails (negative return code), the device should not be added * to the discovered device list. */ int usbi_sanitize_device(struct libusb_device *dev) { int r; unsigned char raw_desc[DEVICE_DESC_LENGTH]; uint8_t num_configurations; int host_endian; r = usbi_backend->get_device_descriptor(dev, raw_desc, &host_endian); if (r < 0) return r; num_configurations = raw_desc[DEVICE_DESC_LENGTH - 1]; if (num_configurations > USB_MAXCONFIG) { usbi_err(DEVICE_CTX(dev), "too many configurations"); return LIBUSB_ERROR_IO; } else if (0 == num_configurations) usbi_dbg("zero configurations, maybe an unauthorized device"); dev->num_configurations = num_configurations; return 0; } /* Examine libusb's internal list of known devices, looking for one with * a specific session ID. Returns the matching device if it was found, and * NULL otherwise. */ struct libusb_device *usbi_get_device_by_session_id(struct libusb_context *ctx, unsigned long session_id) { struct libusb_device *dev; struct libusb_device *ret = NULL; usbi_mutex_lock(&ctx->usb_devs_lock); list_for_each_entry(dev, &ctx->usb_devs, list, struct libusb_device) if (dev->session_data == session_id) { ret = dev; break; } usbi_mutex_unlock(&ctx->usb_devs_lock); return ret; } /** @ingroup dev * Returns a list of USB devices currently attached to the system. This is * your entry point into finding a USB device to operate. * * You are expected to unreference all the devices when you are done with * them, and then free the list with libusb_free_device_list(). Note that * libusb_free_device_list() can unref all the devices for you. Be careful * not to unreference a device you are about to open until after you have * opened it. * * This return value of this function indicates the number of devices in * the resultant list. The list is actually one element larger, as it is * NULL-terminated. * * \param ctx the context to operate on, or NULL for the default context * \param list output location for a list of devices. Must be later freed with * libusb_free_device_list(). * \returns The number of devices in the outputted list, or any * \ref libusb_error according to errors encountered by the backend. */ ssize_t API_EXPORTED libusb_get_device_list(libusb_context *ctx, libusb_device ***list) { struct discovered_devs *discdevs = discovered_devs_alloc(); struct libusb_device **ret; int r = 0; ssize_t i, len; USBI_GET_CONTEXT(ctx); usbi_dbg(""); if (!discdevs) return LIBUSB_ERROR_NO_MEM; r = usbi_backend->get_device_list(ctx, &discdevs); if (r < 0) { len = r; goto out; } /* convert discovered_devs into a list */ len = discdevs->len; ret = malloc(sizeof(void *) * (len + 1)); if (!ret) { len = LIBUSB_ERROR_NO_MEM; goto out; } ret[len] = NULL; for (i = 0; i < len; i++) { struct libusb_device *dev = discdevs->devices[i]; ret[i] = libusb_ref_device(dev); } *list = ret; out: discovered_devs_free(discdevs); return len; } /** \ingroup dev * Frees a list of devices previously discovered using * libusb_get_device_list(). If the unref_devices parameter is set, the * reference count of each device in the list is decremented by 1. * \param list the list to free * \param unref_devices whether to unref the devices in the list */ void API_EXPORTED libusb_free_device_list(libusb_device **list, int unref_devices) { if (!list) return; if (unref_devices) { int i = 0; struct libusb_device *dev; while ((dev = list[i++]) != NULL) libusb_unref_device(dev); } free(list); } /** \ingroup dev * Get the number of the bus that a device is connected to. * \param dev a device * \returns the bus number */ uint8_t API_EXPORTED libusb_get_bus_number(libusb_device *dev) { return dev->bus_number; } /** \ingroup dev * Get the address of the device on the bus it is connected to. * \param dev a device * \returns the device address */ uint8_t API_EXPORTED libusb_get_device_address(libusb_device *dev) { return dev->device_address; } /** \ingroup dev * Get the negotiated connection speed for a device. * \param dev a device * \returns a \ref libusb_speed code, where LIBUSB_SPEED_UNKNOWN means that * the OS doesn't know or doesn't support returning the negotiated speed. */ int API_EXPORTED libusb_get_device_speed(libusb_device *dev) { return dev->speed; } static const struct libusb_endpoint_descriptor *find_endpoint( struct libusb_config_descriptor *config, unsigned char endpoint) { int iface_idx; for (iface_idx = 0; iface_idx < config->bNumInterfaces; iface_idx++) { const struct libusb_interface *iface = &config->interface[iface_idx]; int altsetting_idx; for (altsetting_idx = 0; altsetting_idx < iface->num_altsetting; altsetting_idx++) { const struct libusb_interface_descriptor *altsetting = &iface->altsetting[altsetting_idx]; int ep_idx; for (ep_idx = 0; ep_idx < altsetting->bNumEndpoints; ep_idx++) { const struct libusb_endpoint_descriptor *ep = &altsetting->endpoint[ep_idx]; if (ep->bEndpointAddress == endpoint) return ep; } } } return NULL; } /** \ingroup dev * Convenience function to retrieve the wMaxPacketSize value for a particular * endpoint in the active device configuration. * * This function was originally intended to be of assistance when setting up * isochronous transfers, but a design mistake resulted in this function * instead. It simply returns the wMaxPacketSize value without considering * its contents. If you're dealing with isochronous transfers, you probably * want libusb_get_max_iso_packet_size() instead. * * \param dev a device * \param endpoint address of the endpoint in question * \returns the wMaxPacketSize value * \returns LIBUSB_ERROR_NOT_FOUND if the endpoint does not exist * \returns LIBUSB_ERROR_OTHER on other failure */ int API_EXPORTED libusb_get_max_packet_size(libusb_device *dev, unsigned char endpoint) { struct libusb_config_descriptor *config; const struct libusb_endpoint_descriptor *ep; int r; r = libusb_get_active_config_descriptor(dev, &config); if (r < 0) { usbi_err(DEVICE_CTX(dev), "could not retrieve active config descriptor"); return LIBUSB_ERROR_OTHER; } ep = find_endpoint(config, endpoint); if (!ep) return LIBUSB_ERROR_NOT_FOUND; r = ep->wMaxPacketSize; libusb_free_config_descriptor(config); return r; } /** \ingroup dev * Calculate the maximum packet size which a specific endpoint is capable is * sending or receiving in the duration of 1 microframe * * Only the active configution is examined. The calculation is based on the * wMaxPacketSize field in the endpoint descriptor as described in section * 9.6.6 in the USB 2.0 specifications. * * If acting on an isochronous or interrupt endpoint, this function will * multiply the value found in bits 0:10 by the number of transactions per * microframe (determined by bits 11:12). Otherwise, this function just * returns the numeric value found in bits 0:10. * * This function is useful for setting up isochronous transfers, for example * you might pass the return value from this function to * libusb_set_iso_packet_lengths() in order to set the length field of every * isochronous packet in a transfer. * * Since v1.0.3. * * \param dev a device * \param endpoint address of the endpoint in question * \returns the maximum packet size which can be sent/received on this endpoint * \returns LIBUSB_ERROR_NOT_FOUND if the endpoint does not exist * \returns LIBUSB_ERROR_OTHER on other failure */ int API_EXPORTED libusb_get_max_iso_packet_size(libusb_device *dev, unsigned char endpoint) { struct libusb_config_descriptor *config; const struct libusb_endpoint_descriptor *ep; enum libusb_transfer_type ep_type; uint16_t val; int r; r = libusb_get_active_config_descriptor(dev, &config); if (r < 0) { usbi_err(DEVICE_CTX(dev), "could not retrieve active config descriptor"); return LIBUSB_ERROR_OTHER; } ep = find_endpoint(config, endpoint); if (!ep) return LIBUSB_ERROR_NOT_FOUND; val = ep->wMaxPacketSize; ep_type = ep->bmAttributes & 0x3; libusb_free_config_descriptor(config); r = val & 0x07ff; if (ep_type == LIBUSB_TRANSFER_TYPE_ISOCHRONOUS || ep_type == LIBUSB_TRANSFER_TYPE_INTERRUPT) r *= (1 + ((val >> 11) & 3)); return r; } /** \ingroup dev * Increment the reference count of a device. * \param dev the device to reference * \returns the same device */ DEFAULT_VISIBILITY libusb_device * LIBUSB_CALL libusb_ref_device(libusb_device *dev) { usbi_mutex_lock(&dev->lock); dev->refcnt++; usbi_mutex_unlock(&dev->lock); return dev; } /** \ingroup dev * Decrement the reference count of a device. If the decrement operation * causes the reference count to reach zero, the device shall be destroyed. * \param dev the device to unreference */ void API_EXPORTED libusb_unref_device(libusb_device *dev) { int refcnt; if (!dev) return; usbi_mutex_lock(&dev->lock); refcnt = --dev->refcnt; usbi_mutex_unlock(&dev->lock); if (refcnt == 0) { usbi_dbg("destroy device %d.%d", dev->bus_number, dev->device_address); if (usbi_backend->destroy_device) usbi_backend->destroy_device(dev); usbi_mutex_lock(&dev->ctx->usb_devs_lock); list_del(&dev->list); usbi_mutex_unlock(&dev->ctx->usb_devs_lock); usbi_mutex_destroy(&dev->lock); free(dev); } } /* * Interrupt the iteration of the event handling thread, so that it picks * up the new fd. */ void usbi_fd_notification(struct libusb_context *ctx) { unsigned char dummy = 1; ssize_t r; if (ctx == NULL) return; /* record that we are messing with poll fds */ usbi_mutex_lock(&ctx->pollfd_modify_lock); ctx->pollfd_modify++; usbi_mutex_unlock(&ctx->pollfd_modify_lock); /* write some data on control pipe to interrupt event handlers */ r = usbi_write(ctx->ctrl_pipe[1], &dummy, sizeof(dummy)); if (r <= 0) { usbi_warn(ctx, "internal signalling write failed"); usbi_mutex_lock(&ctx->pollfd_modify_lock); ctx->pollfd_modify--; usbi_mutex_unlock(&ctx->pollfd_modify_lock); return; } /* take event handling lock */ libusb_lock_events(ctx); /* read the dummy data */ r = usbi_read(ctx->ctrl_pipe[0], &dummy, sizeof(dummy)); if (r <= 0) usbi_warn(ctx, "internal signalling read failed"); /* we're done with modifying poll fds */ usbi_mutex_lock(&ctx->pollfd_modify_lock); ctx->pollfd_modify--; usbi_mutex_unlock(&ctx->pollfd_modify_lock); /* Release event handling lock and wake up event waiters */ libusb_unlock_events(ctx); } /** \ingroup dev * Open a device and obtain a device handle. A handle allows you to perform * I/O on the device in question. * * Internally, this function adds a reference to the device and makes it * available to you through libusb_get_device(). This reference is removed * during libusb_close(). * * This is a non-blocking function; no requests are sent over the bus. * * \param dev the device to open * \param handle output location for the returned device handle pointer. Only * populated when the return code is 0. * \returns 0 on success * \returns LIBUSB_ERROR_NO_MEM on memory allocation failure * \returns LIBUSB_ERROR_ACCESS if the user has insufficient permissions * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected * \returns another LIBUSB_ERROR code on other failure */ int API_EXPORTED libusb_open(libusb_device *dev, libusb_device_handle **handle) { struct libusb_context *ctx = DEVICE_CTX(dev); struct libusb_device_handle *_handle; size_t priv_size = usbi_backend->device_handle_priv_size; int r; usbi_dbg("open %d.%d", dev->bus_number, dev->device_address); _handle = malloc(sizeof(*_handle) + priv_size); if (!_handle) return LIBUSB_ERROR_NO_MEM; r = usbi_mutex_init(&_handle->lock, NULL); if (r) { free(_handle); return LIBUSB_ERROR_OTHER; } _handle->dev = libusb_ref_device(dev); _handle->claimed_interfaces = 0; memset(&_handle->os_priv, 0, priv_size); r = usbi_backend->open(_handle); if (r < 0) { usbi_dbg("open %d.%d returns %d", dev->bus_number, dev->device_address, r); libusb_unref_device(dev); usbi_mutex_destroy(&_handle->lock); free(_handle); return r; } usbi_mutex_lock(&ctx->open_devs_lock); list_add(&_handle->list, &ctx->open_devs); usbi_mutex_unlock(&ctx->open_devs_lock); *handle = _handle; /* At this point, we want to interrupt any existing event handlers so * that they realise the addition of the new device's poll fd. One * example when this is desirable is if the user is running a separate * dedicated libusb events handling thread, which is running with a long * or infinite timeout. We want to interrupt that iteration of the loop, * so that it picks up the new fd, and then continues. */ usbi_fd_notification(ctx); return 0; } /** \ingroup dev * Convenience function for finding a device with a particular * <tt>idVendor</tt>/<tt>idProduct</tt> combination. This function is intended * for those scenarios where you are using libusb to knock up a quick test * application - it allows you to avoid calling libusb_get_device_list() and * worrying about traversing/freeing the list. * * This function has limitations and is hence not intended for use in real * applications: if multiple devices have the same IDs it will only * give you the first one, etc. * * \param ctx the context to operate on, or NULL for the default context * \param vendor_id the idVendor value to search for * \param product_id the idProduct value to search for * \returns a handle for the first found device, or NULL on error or if the * device could not be found. */ DEFAULT_VISIBILITY libusb_device_handle * LIBUSB_CALL libusb_open_device_with_vid_pid( libusb_context *ctx, uint16_t vendor_id, uint16_t product_id) { struct libusb_device **devs; struct libusb_device *found = NULL; struct libusb_device *dev; struct libusb_device_handle *handle = NULL; size_t i = 0; int r; if (libusb_get_device_list(ctx, &devs) < 0) return NULL; while ((dev = devs[i++]) != NULL) { struct libusb_device_descriptor desc; r = libusb_get_device_descriptor(dev, &desc); if (r < 0) goto out; if (desc.idVendor == vendor_id && desc.idProduct == product_id) { found = dev; break; } } if (found) { r = libusb_open(found, &handle); if (r < 0) handle = NULL; } out: libusb_free_device_list(devs, 1); return handle; } static void do_close(struct libusb_context *ctx, struct libusb_device_handle *dev_handle) { struct usbi_transfer *itransfer; struct usbi_transfer *tmp; libusb_lock_events(ctx); /* remove any transfers in flight that are for this device */ usbi_mutex_lock(&ctx->flying_transfers_lock); /* safe iteration because transfers may be being deleted */ list_for_each_entry_safe(itransfer, tmp, &ctx->flying_transfers, list, struct usbi_transfer) { struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer); if (transfer->dev_handle != dev_handle) continue; if (!(itransfer->flags & USBI_TRANSFER_DEVICE_DISAPPEARED)) { usbi_err(ctx, "Device handle closed while transfer was still being processed, but the device is still connected as far as we know"); if (itransfer->flags & USBI_TRANSFER_CANCELLING) usbi_warn(ctx, "A cancellation for an in-flight transfer hasn't completed but closing the device handle"); else usbi_err(ctx, "A cancellation hasn't even been scheduled on the transfer for which the device is closing"); } /* remove from the list of in-flight transfers and make sure * we don't accidentally use the device handle in the future * (or that such accesses will be easily caught and identified as a crash) */ usbi_mutex_lock(&itransfer->lock); list_del(&itransfer->list); transfer->dev_handle = NULL; usbi_mutex_unlock(&itransfer->lock); /* it is up to the user to free up the actual transfer struct. this is * just making sure that we don't attempt to process the transfer after * the device handle is invalid */ usbi_dbg("Removed transfer %p from the in-flight list because device handle %p closed", transfer, dev_handle); } usbi_mutex_unlock(&ctx->flying_transfers_lock); libusb_unlock_events(ctx); usbi_mutex_lock(&ctx->open_devs_lock); list_del(&dev_handle->list); usbi_mutex_unlock(&ctx->open_devs_lock); usbi_backend->close(dev_handle); libusb_unref_device(dev_handle->dev); usbi_mutex_destroy(&dev_handle->lock); free(dev_handle); } /** \ingroup dev * Close a device handle. Should be called on all open handles before your * application exits. * * Internally, this function destroys the reference that was added by * libusb_open() on the given device. * * This is a non-blocking function; no requests are sent over the bus. * * \param dev_handle the handle to close */ void API_EXPORTED libusb_close(libusb_device_handle *dev_handle) { struct libusb_context *ctx; unsigned char dummy = 1; ssize_t r; if (!dev_handle) return; usbi_dbg(""); ctx = HANDLE_CTX(dev_handle); /* Similarly to libusb_open(), we want to interrupt all event handlers * at this point. More importantly, we want to perform the actual close of * the device while holding the event handling lock (preventing any other * thread from doing event handling) because we will be removing a file * descriptor from the polling loop. */ /* record that we are messing with poll fds */ usbi_mutex_lock(&ctx->pollfd_modify_lock); ctx->pollfd_modify++; usbi_mutex_unlock(&ctx->pollfd_modify_lock); /* write some data on control pipe to interrupt event handlers */ r = usbi_write(ctx->ctrl_pipe[1], &dummy, sizeof(dummy)); if (r <= 0) { usbi_warn(ctx, "internal signalling write failed, closing anyway"); do_close(ctx, dev_handle); usbi_mutex_lock(&ctx->pollfd_modify_lock); ctx->pollfd_modify--; usbi_mutex_unlock(&ctx->pollfd_modify_lock); return; } /* take event handling lock */ libusb_lock_events(ctx); /* read the dummy data */ r = usbi_read(ctx->ctrl_pipe[0], &dummy, sizeof(dummy)); if (r <= 0) usbi_warn(ctx, "internal signalling read failed, closing anyway"); /* Close the device */ do_close(ctx, dev_handle); /* we're done with modifying poll fds */ usbi_mutex_lock(&ctx->pollfd_modify_lock); ctx->pollfd_modify--; usbi_mutex_unlock(&ctx->pollfd_modify_lock); /* Release event handling lock and wake up event waiters */ libusb_unlock_events(ctx); } /** \ingroup dev * Get the underlying device for a handle. This function does not modify * the reference count of the returned device, so do not feel compelled to * unreference it when you are done. * \param dev_handle a device handle * \returns the underlying device */ DEFAULT_VISIBILITY libusb_device * LIBUSB_CALL libusb_get_device(libusb_device_handle *dev_handle) { return dev_handle->dev; } /** \ingroup dev * Determine the bConfigurationValue of the currently active configuration. * * You could formulate your own control request to obtain this information, * but this function has the advantage that it may be able to retrieve the * information from operating system caches (no I/O involved). * * If the OS does not cache this information, then this function will block * while a control transfer is submitted to retrieve the information. * * This function will return a value of 0 in the <tt>config</tt> output * parameter if the device is in unconfigured state. * * \param dev a device handle * \param config output location for the bConfigurationValue of the active * configuration (only valid for return code 0) * \returns 0 on success * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected * \returns another LIBUSB_ERROR code on other failure */ int API_EXPORTED libusb_get_configuration(libusb_device_handle *dev, int *config) { int r = LIBUSB_ERROR_NOT_SUPPORTED; usbi_dbg(""); if (usbi_backend->get_configuration) r = usbi_backend->get_configuration(dev, config); if (r == LIBUSB_ERROR_NOT_SUPPORTED) { uint8_t tmp = 0; usbi_dbg("falling back to control message"); r = libusb_control_transfer(dev, LIBUSB_ENDPOINT_IN, LIBUSB_REQUEST_GET_CONFIGURATION, 0, 0, &tmp, 1, 1000); if (r == 0) { usbi_err(HANDLE_CTX(dev), "zero bytes returned in ctrl transfer?"); r = LIBUSB_ERROR_IO; } else if (r == 1) { r = 0; *config = tmp; } else { usbi_dbg("control failed, error %d", r); } } if (r == 0) usbi_dbg("active config %d", *config); return r; } /** \ingroup dev * Set the active configuration for a device. * * The operating system may or may not have already set an active * configuration on the device. It is up to your application to ensure the * correct configuration is selected before you attempt to claim interfaces * and perform other operations. * * If you call this function on a device already configured with the selected * configuration, then this function will act as a lightweight device reset: * it will issue a SET_CONFIGURATION request using the current configuration, * causing most USB-related device state to be reset (altsetting reset to zero, * endpoint halts cleared, toggles reset). * * You cannot change/reset configuration if your application has claimed * interfaces - you should free them with libusb_release_interface() first. * You cannot change/reset configuration if other applications or drivers have * claimed interfaces. * * A configuration value of -1 will put the device in unconfigured state. * The USB specifications state that a configuration value of 0 does this, * however buggy devices exist which actually have a configuration 0. * * You should always use this function rather than formulating your own * SET_CONFIGURATION control request. This is because the underlying operating * system needs to know when such changes happen. * * This is a blocking function. * * \param dev a device handle * \param configuration the bConfigurationValue of the configuration you * wish to activate, or -1 if you wish to put the device in unconfigured state * \returns 0 on success * \returns LIBUSB_ERROR_NOT_FOUND if the requested configuration does not exist * \returns LIBUSB_ERROR_BUSY if interfaces are currently claimed * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected * \returns another LIBUSB_ERROR code on other failure */ int API_EXPORTED libusb_set_configuration(libusb_device_handle *dev, int configuration) { usbi_dbg("configuration %d", configuration); return usbi_backend->set_configuration(dev, configuration); } /** \ingroup dev * Claim an interface on a given device handle. You must claim the interface * you wish to use before you can perform I/O on any of its endpoints. * * It is legal to attempt to claim an already-claimed interface, in which * case libusb just returns 0 without doing anything. * * Claiming of interfaces is a purely logical operation; it does not cause * any requests to be sent over the bus. Interface claiming is used to * instruct the underlying operating system that your application wishes * to take ownership of the interface. * * This is a non-blocking function. * * \param dev a device handle * \param interface_number the <tt>bInterfaceNumber</tt> of the interface you * wish to claim * \returns 0 on success * \returns LIBUSB_ERROR_NOT_FOUND if the requested interface does not exist * \returns LIBUSB_ERROR_BUSY if another program or driver has claimed the * interface * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected * \returns a LIBUSB_ERROR code on other failure */ int API_EXPORTED libusb_claim_interface(libusb_device_handle *dev, int interface_number) { int r = 0; usbi_dbg("interface %d", interface_number); if (interface_number >= USB_MAXINTERFACES) return LIBUSB_ERROR_INVALID_PARAM; usbi_mutex_lock(&dev->lock); if (dev->claimed_interfaces & (1 << interface_number)) goto out; r = usbi_backend->claim_interface(dev, interface_number); if (r == 0) dev->claimed_interfaces |= 1 << interface_number; out: usbi_mutex_unlock(&dev->lock); return r; } /** \ingroup dev * Release an interface previously claimed with libusb_claim_interface(). You * should release all claimed interfaces before closing a device handle. * * This is a blocking function. A SET_INTERFACE control request will be sent * to the device, resetting interface state to the first alternate setting. * * \param dev a device handle * \param interface_number the <tt>bInterfaceNumber</tt> of the * previously-claimed interface * \returns 0 on success * \returns LIBUSB_ERROR_NOT_FOUND if the interface was not claimed * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected * \returns another LIBUSB_ERROR code on other failure */ int API_EXPORTED libusb_release_interface(libusb_device_handle *dev, int interface_number) { int r; usbi_dbg("interface %d", interface_number); if (interface_number >= USB_MAXINTERFACES) return LIBUSB_ERROR_INVALID_PARAM; usbi_mutex_lock(&dev->lock); if (!(dev->claimed_interfaces & (1 << interface_number))) { r = LIBUSB_ERROR_NOT_FOUND; goto out; } r = usbi_backend->release_interface(dev, interface_number); if (r == 0) dev->claimed_interfaces &= ~(1 << interface_number); out: usbi_mutex_unlock(&dev->lock); return r; } /** \ingroup dev * Activate an alternate setting for an interface. The interface must have * been previously claimed with libusb_claim_interface(). * * You should always use this function rather than formulating your own * SET_INTERFACE control request. This is because the underlying operating * system needs to know when such changes happen. * * This is a blocking function. * * \param dev a device handle * \param interface_number the <tt>bInterfaceNumber</tt> of the * previously-claimed interface * \param alternate_setting the <tt>bAlternateSetting</tt> of the alternate * setting to activate * \returns 0 on success * \returns LIBUSB_ERROR_NOT_FOUND if the interface was not claimed, or the * requested alternate setting does not exist * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected * \returns another LIBUSB_ERROR code on other failure */ int API_EXPORTED libusb_set_interface_alt_setting(libusb_device_handle *dev, int interface_number, int alternate_setting) { usbi_dbg("interface %d altsetting %d", interface_number, alternate_setting); if (interface_number >= USB_MAXINTERFACES) return LIBUSB_ERROR_INVALID_PARAM; usbi_mutex_lock(&dev->lock); if (!(dev->claimed_interfaces & (1 << interface_number))) { usbi_mutex_unlock(&dev->lock); return LIBUSB_ERROR_NOT_FOUND; } usbi_mutex_unlock(&dev->lock); return usbi_backend->set_interface_altsetting(dev, interface_number, alternate_setting); } /** \ingroup dev * Clear the halt/stall condition for an endpoint. Endpoints with halt status * are unable to receive or transmit data until the halt condition is stalled. * * You should cancel all pending transfers before attempting to clear the halt * condition. * * This is a blocking function. * * \param dev a device handle * \param endpoint the endpoint to clear halt status * \returns 0 on success * \returns LIBUSB_ERROR_NOT_FOUND if the endpoint does not exist * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected * \returns another LIBUSB_ERROR code on other failure */ int API_EXPORTED libusb_clear_halt(libusb_device_handle *dev, unsigned char endpoint) { usbi_dbg("endpoint %x", endpoint); return usbi_backend->clear_halt(dev, endpoint); } /** \ingroup dev * Perform a USB port reset to reinitialize a device. The system will attempt * to restore the previous configuration and alternate settings after the * reset has completed. * * If the reset fails, the descriptors change, or the previous state cannot be * restored, the device will appear to be disconnected and reconnected. This * means that the device handle is no longer valid (you should close it) and * rediscover the device. A return code of LIBUSB_ERROR_NOT_FOUND indicates * when this is the case. * * This is a blocking function which usually incurs a noticeable delay. * * \param dev a handle of the device to reset * \returns 0 on success * \returns LIBUSB_ERROR_NOT_FOUND if re-enumeration is required, or if the * device has been disconnected * \returns another LIBUSB_ERROR code on other failure */ int API_EXPORTED libusb_reset_device(libusb_device_handle *dev) { usbi_dbg(""); return usbi_backend->reset_device(dev); } /** \ingroup dev * Determine if a kernel driver is active on an interface. If a kernel driver * is active, you cannot claim the interface, and libusb will be unable to * perform I/O. * * This functionality is not available on Windows. * * \param dev a device handle * \param interface_number the interface to check * \returns 0 if no kernel driver is active * \returns 1 if a kernel driver is active * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected * \returns LIBUSB_ERROR_NOT_SUPPORTED on platforms where the functionality * is not available * \returns another LIBUSB_ERROR code on other failure * \see libusb_detach_kernel_driver() */ int API_EXPORTED libusb_kernel_driver_active(libusb_device_handle *dev, int interface_number) { usbi_dbg("interface %d", interface_number); if (usbi_backend->kernel_driver_active) return usbi_backend->kernel_driver_active(dev, interface_number); else return LIBUSB_ERROR_NOT_SUPPORTED; } /** \ingroup dev * Detach a kernel driver from an interface. If successful, you will then be * able to claim the interface and perform I/O. * * This functionality is not available on Darwin or Windows. * * \param dev a device handle * \param interface_number the interface to detach the driver from * \returns 0 on success * \returns LIBUSB_ERROR_NOT_FOUND if no kernel driver was active * \returns LIBUSB_ERROR_INVALID_PARAM if the interface does not exist * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected * \returns LIBUSB_ERROR_NOT_SUPPORTED on platforms where the functionality * is not available * \returns another LIBUSB_ERROR code on other failure * \see libusb_kernel_driver_active() */ int API_EXPORTED libusb_detach_kernel_driver(libusb_device_handle *dev, int interface_number) { usbi_dbg("interface %d", interface_number); if (usbi_backend->detach_kernel_driver) return usbi_backend->detach_kernel_driver(dev, interface_number); else return LIBUSB_ERROR_NOT_SUPPORTED; } /** \ingroup dev * Re-attach an interface's kernel driver, which was previously detached * using libusb_detach_kernel_driver(). This call is only effective on * Linux and returns LIBUSB_ERROR_NOT_SUPPORTED on all other platforms. * * This functionality is not available on Darwin or Windows. * * \param dev a device handle * \param interface_number the interface to attach the driver from * \returns 0 on success * \returns LIBUSB_ERROR_NOT_FOUND if no kernel driver was active * \returns LIBUSB_ERROR_INVALID_PARAM if the interface does not exist * \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected * \returns LIBUSB_ERROR_NOT_SUPPORTED on platforms where the functionality * is not available * \returns LIBUSB_ERROR_BUSY if the driver cannot be attached because the * interface is claimed by a program or driver * \returns another LIBUSB_ERROR code on other failure * \see libusb_kernel_driver_active() */ int API_EXPORTED libusb_attach_kernel_driver(libusb_device_handle *dev, int interface_number) { usbi_dbg("interface %d", interface_number); if (usbi_backend->attach_kernel_driver) return usbi_backend->attach_kernel_driver(dev, interface_number); else return LIBUSB_ERROR_NOT_SUPPORTED; } /** \ingroup lib * Set message verbosity. * - Level 0: no messages ever printed by the library (default) * - Level 1: error messages are printed to stderr * - Level 2: warning and error messages are printed to stderr * - Level 3: informational messages are printed to stdout, warning and error * messages are printed to stderr * * The default level is 0, which means no messages are ever printed. If you * choose to increase the message verbosity level, ensure that your * application does not close the stdout/stderr file descriptors. * * You are advised to set level 3. libusb is conservative with its message * logging and most of the time, will only log messages that explain error * conditions and other oddities. This will help you debug your software. * * If the LIBUSB_DEBUG environment variable was set when libusb was * initialized, this function does nothing: the message verbosity is fixed * to the value in the environment variable. * * If libusb was compiled without any message logging, this function does * nothing: you'll never get any messages. * * If libusb was compiled with verbose debug message logging, this function * does nothing: you'll always get messages from all levels. * * \param ctx the context to operate on, or NULL for the default context * \param level debug level to set */ void API_EXPORTED libusb_set_debug(libusb_context *ctx, int level) { USBI_GET_CONTEXT(ctx); if (!ctx->debug_fixed) ctx->debug = level; } /** \ingroup lib * Initialize libusb. This function must be called before calling any other * libusb function. * * If you do not provide an output location for a context pointer, a default * context will be created. If there was already a default context, it will * be reused (and nothing will be initialized/reinitialized). * * \param context Optional output location for context pointer. * Only valid on return code 0. * \returns 0 on success, or a LIBUSB_ERROR code on failure * \see contexts */ int API_EXPORTED libusb_init(libusb_context **context) { char *dbg = getenv("LIBUSB_DEBUG"); struct libusb_context *ctx; int r = 0; usbi_mutex_static_lock(&default_context_lock); if (!context && usbi_default_context) { usbi_dbg("reusing default context"); default_context_refcnt++; usbi_mutex_static_unlock(&default_context_lock); return 0; } ctx = malloc(sizeof(*ctx)); if (!ctx) { r = LIBUSB_ERROR_NO_MEM; goto err_unlock; } memset(ctx, 0, sizeof(*ctx)); if (dbg) { ctx->debug = atoi(dbg); if (ctx->debug) ctx->debug_fixed = 1; } usbi_dbg("libusb-%d.%d.%d%s%s%s", libusb_version_internal.major, libusb_version_internal.minor, libusb_version_internal.micro, libusb_version_internal.rc, libusb_version_internal.describe[0] ? " git:" : "", libusb_version_internal.describe); if (usbi_backend->init) { r = usbi_backend->init(ctx); if (r) goto err_free_ctx; } usbi_mutex_init(&ctx->usb_devs_lock, NULL); usbi_mutex_init(&ctx->open_devs_lock, NULL); list_init(&ctx->usb_devs); list_init(&ctx->open_devs); r = usbi_io_init(ctx); if (r < 0) { if (usbi_backend->exit) usbi_backend->exit(); goto err_destroy_mutex; } if (context) { *context = ctx; } else if (!usbi_default_context) { usbi_dbg("created default context"); usbi_default_context = ctx; default_context_refcnt++; } usbi_mutex_static_unlock(&default_context_lock); return 0; err_destroy_mutex: usbi_mutex_destroy(&ctx->open_devs_lock); usbi_mutex_destroy(&ctx->usb_devs_lock); err_free_ctx: free(ctx); err_unlock: usbi_mutex_static_unlock(&default_context_lock); return r; } /** \ingroup lib * Deinitialize libusb. Should be called after closing all open devices and * before your application terminates. * \param ctx the context to deinitialize, or NULL for the default context */ void API_EXPORTED libusb_exit(struct libusb_context *ctx) { usbi_dbg(""); USBI_GET_CONTEXT(ctx); /* if working with default context, only actually do the deinitialization * if we're the last user */ if (ctx == usbi_default_context) { usbi_mutex_static_lock(&default_context_lock); if (--default_context_refcnt > 0) { usbi_dbg("not destroying default context"); usbi_mutex_static_unlock(&default_context_lock); return; } usbi_dbg("destroying default context"); usbi_default_context = NULL; usbi_mutex_static_unlock(&default_context_lock); } /* a little sanity check. doesn't bother with open_devs locking because * unless there is an application bug, nobody will be accessing this. */ if (!list_empty(&ctx->open_devs)) usbi_warn(ctx, "application left some devices open"); usbi_io_exit(ctx); if (usbi_backend->exit) usbi_backend->exit(); usbi_mutex_destroy(&ctx->open_devs_lock); usbi_mutex_destroy(&ctx->usb_devs_lock); free(ctx); } /** \ingroup misc * Check at runtime if the loaded library has a given capability. * * \param capability the \ref libusb_capability to check for * \returns 1 if the running library has the capability, 0 otherwise */ int API_EXPORTED libusb_has_capability(uint32_t capability) { enum libusb_capability cap = capability; switch (cap) { case LIBUSB_CAP_HAS_CAPABILITY: return 1; } return 0; } /* this is defined in libusbi.h if needed */ #ifdef LIBUSB_GETTIMEOFDAY_WIN32 /* * gettimeofday * Implementation according to: * The Open Group Base Specifications Issue 6 * IEEE Std 1003.1, 2004 Edition */ /* * THIS SOFTWARE IS NOT COPYRIGHTED * * This source code is offered for use in the public domain. You may * use, modify or distribute it freely. * * This code is distributed in the hope that it will be useful but * WITHOUT ANY WARRANTY. ALL WARRANTIES, EXPRESS OR IMPLIED ARE HEREBY * DISCLAIMED. This includes but is not limited to warranties of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. * * Contributed by: * Danny Smith <dannysmith@users.sourceforge.net> */ /* Offset between 1/1/1601 and 1/1/1970 in 100 nanosec units */ #define _W32_FT_OFFSET (116444736000000000) int usbi_gettimeofday(struct timeval *tp, void *tzp) { union { unsigned __int64 ns100; /*time since 1 Jan 1601 in 100ns units */ FILETIME ft; } _now; if(tp) { GetSystemTimeAsFileTime (&_now.ft); tp->tv_usec=(long)((_now.ns100 / 10) % 1000000 ); tp->tv_sec= (long)((_now.ns100 - _W32_FT_OFFSET) / 10000000); } /* Always return 0 as per Open Group Base Specifications Issue 6. Do not set errno on error. */ return 0; } #endif void usbi_log_v(struct libusb_context *ctx, enum usbi_log_level level, const char *function, const char *format, va_list args) { FILE *stream = stdout; const char *prefix; struct timeval now; static struct timeval first = { 0, 0 }; #ifndef ENABLE_DEBUG_LOGGING USBI_GET_CONTEXT(ctx); if (!ctx->debug) return; if (level == LOG_LEVEL_WARNING && ctx->debug < 2) return; if (level == LOG_LEVEL_INFO && ctx->debug < 3) return; #endif usbi_gettimeofday(&now, NULL); if (!first.tv_sec) { first.tv_sec = now.tv_sec; first.tv_usec = now.tv_usec; } if (now.tv_usec < first.tv_usec) { now.tv_sec--; now.tv_usec += 1000000; } now.tv_sec -= first.tv_sec; now.tv_usec -= first.tv_usec; switch (level) { case LOG_LEVEL_INFO: prefix = "info"; break; case LOG_LEVEL_WARNING: stream = stderr; prefix = "warning"; break; case LOG_LEVEL_ERROR: stream = stderr; prefix = "error"; break; case LOG_LEVEL_DEBUG: stream = stderr; prefix = "debug"; break; default: stream = stderr; prefix = "unknown"; break; } fprintf(stream, "libusb: %d.%06d %s [%s] ", (int)now.tv_sec, (int)now.tv_usec, prefix, function); vfprintf(stream, format, args); fprintf(stream, "\n"); } void usbi_log(struct libusb_context *ctx, enum usbi_log_level level, const char *function, const char *format, ...) { va_list args; va_start (args, format); usbi_log_v(ctx, level, function, format, args); va_end (args); } /** \ingroup misc * Returns a constant NULL-terminated string with the ASCII name of a libusb * error code. The caller must not free() the returned string. * * \param error_code The \ref libusb_error code to return the name of. * \returns The error name, or the string **UNKNOWN** if the value of * error_code is not a known error code. */ DEFAULT_VISIBILITY const char * LIBUSB_CALL libusb_error_name(int error_code) { enum libusb_error error = error_code; switch (error) { case LIBUSB_SUCCESS: return "LIBUSB_SUCCESS"; case LIBUSB_ERROR_IO: return "LIBUSB_ERROR_IO"; case LIBUSB_ERROR_INVALID_PARAM: return "LIBUSB_ERROR_INVALID_PARAM"; case LIBUSB_ERROR_ACCESS: return "LIBUSB_ERROR_ACCESS"; case LIBUSB_ERROR_NO_DEVICE: return "LIBUSB_ERROR_NO_DEVICE"; case LIBUSB_ERROR_NOT_FOUND: return "LIBUSB_ERROR_NOT_FOUND"; case LIBUSB_ERROR_BUSY: return "LIBUSB_ERROR_BUSY"; case LIBUSB_ERROR_TIMEOUT: return "LIBUSB_ERROR_TIMEOUT"; case LIBUSB_ERROR_OVERFLOW: return "LIBUSB_ERROR_OVERFLOW"; case LIBUSB_ERROR_PIPE: return "LIBUSB_ERROR_PIPE"; case LIBUSB_ERROR_INTERRUPTED: return "LIBUSB_ERROR_INTERRUPTED"; case LIBUSB_ERROR_NO_MEM: return "LIBUSB_ERROR_NO_MEM"; case LIBUSB_ERROR_NOT_SUPPORTED: return "LIBUSB_ERROR_NOT_SUPPORTED"; case LIBUSB_ERROR_OTHER: return "LIBUSB_ERROR_OTHER"; } return "**UNKNOWN**"; } /** \ingroup misc * Returns a pointer to const struct libusb_version with the version * (major, minor, micro, rc, and nano) of the running library. */ DEFAULT_VISIBILITY const struct libusb_version * LIBUSB_CALL libusb_get_version(void) { return &libusb_version_internal; }