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Diffstat (limited to 'libusb-1.0/libusb/core.c')
| -rw-r--r-- | libusb-1.0/libusb/core.c | 1738 |
1 files changed, 1738 insertions, 0 deletions
diff --git a/libusb-1.0/libusb/core.c b/libusb-1.0/libusb/core.c new file mode 100644 index 0000000..46c2b9c --- /dev/null +++ b/libusb-1.0/libusb/core.c @@ -0,0 +1,1738 @@ +/* + * 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> + +#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_WINDOWS) +const struct usbi_os_backend * const usbi_backend = &windows_backend; +#else +#error "Unsupported OS" +#endif + +struct libusb_context *usbi_default_context = NULL; +const struct libusb_version libusb_version_internal = { LIBUSB_VERSION_MAJOR, +LIBUSB_VERSION_MINOR, LIBUSB_VERSION_MICRO, LIBUSB_VERSION_NANO}; +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. + */ + +/** + * \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 = malloc(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; + 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 (num_configurations < 1) { + usbi_dbg("no configurations?"); + return LIBUSB_ERROR_IO; + } + + 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 LIBUSB_ERROR_NO_MEM + * on memory allocation failure. + */ +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; +} + +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) { + 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) +{ + 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 >= sizeof(dev->claimed_interfaces) * 8) + 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 >= sizeof(dev->claimed_interfaces) * 8) + 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 >= sizeof(dev->claimed_interfaces) * 8) + 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; + + usbi_mutex_static_lock(&default_context_lock); + if (!context && usbi_default_context) { + r = 0; + 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; + } + + // default context should be initialized before any call to usbi_dbg + if (!usbi_default_context) { + usbi_default_context = ctx; + usbi_dbg("created default context"); + } + + usbi_dbg(""); + + 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: + if (usbi_default_context == ctx) + usbi_default_context = NULL; + 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_GET_CONTEXT(ctx); + usbi_dbg(""); + + /* 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); +} + +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; + +#ifndef ENABLE_DEBUG_LOGGING + USBI_GET_CONTEXT(ctx); + if (ctx == NULL) + return; + if (!ctx->debug) + return; + if (level == LOG_LEVEL_WARNING && ctx->debug < 2) + return; + if (level == LOG_LEVEL_INFO && ctx->debug < 3) + return; + if (level == LOG_LEVEL_DEBUG && ctx->debug < 4) + return; +#endif + + 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:%s [%s] ", 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 an English short description + * of the given error code. The caller should never free() the returned pointer + * since it points to a constant string. + * The returned string is encoded in ASCII form and always starts with a + * capital letter and ends without any punctuation. + * Future versions of libusb may return NULL if the library is compiled without + * these messages included (e.g. for embedded systems). + * This function is intended to be used for debugging purposes only. + * + * \param errcode the error code whose description is desired + * \returns a short description of the error code in English, or NULL if the + * error descriptions are unavailable + */ +DEFAULT_VISIBILITY +const char * LIBUSB_CALL libusb_strerror(enum libusb_error error_code) +{ + switch (error_code) { + case LIBUSB_SUCCESS: + return "Success"; + case LIBUSB_ERROR_IO: + return "Input/output error"; + case LIBUSB_ERROR_INVALID_PARAM: + return "Invalid parameter"; + case LIBUSB_ERROR_ACCESS: + return "Access denied (insufficient permissions)"; + case LIBUSB_ERROR_NO_DEVICE: + return "No such device (it may have been disconnected)"; + case LIBUSB_ERROR_NOT_FOUND: + return "Entity not found"; + case LIBUSB_ERROR_BUSY: + return "Resource busy"; + case LIBUSB_ERROR_TIMEOUT: + return "Operation timed out"; + case LIBUSB_ERROR_OVERFLOW: + return "Overflow"; + case LIBUSB_ERROR_PIPE: + return "Pipe error"; + case LIBUSB_ERROR_INTERRUPTED: + return "System call interrupted (perhaps due to signal)"; + case LIBUSB_ERROR_NO_MEM: + return "Insufficient memory"; + case LIBUSB_ERROR_NOT_SUPPORTED: + return "Operation not supported or unimplemented on this platform"; + case LIBUSB_ERROR_OTHER: + return "Other error"; + } + return "Unknown error"; +} + +/** \ingroup misc + * Fills a libusb_version struct with the full version (major, minor, + * micro, nano) of this library + */ +DEFAULT_VISIBILITY +const struct libusb_version * LIBUSB_CALL libusb_getversion(void) +{ + return &libusb_version_internal; +} |