/*
- * I/O functions for libusb
- * Copyright (C) 2007-2008 Daniel Drake <dsd@gentoo.org>
- * Copyright (c) 2001 Johannes Erdfelt <johannes@erdfelt.com>
+ * I/O functions for libusbx
+ * Copyright © 2007-2009 Daniel Drake <dsd@gentoo.org>
+ * Copyright © 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
#include <config.h>
#include <errno.h>
-#include <poll.h>
-#include <pthread.h>
#include <signal.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
-#include <sys/time.h>
#include <time.h>
-#include <unistd.h>
+
+#ifdef HAVE_SYS_TIME_H
+#include <sys/time.h>
+#endif
+
+#ifdef USBI_TIMERFD_AVAILABLE
+#include <sys/timerfd.h>
+#endif
#include "libusbi.h"
*
* \section intro Introduction
*
- * If you're using libusb in your application, you're probably wanting to
+ * If you're using libusbx in your application, you're probably wanting to
* perform I/O with devices - you want to perform USB data transfers.
*
- * libusb offers two separate interfaces for device I/O. This page aims to
+ * libusbx offers two separate interfaces for device I/O. This page aims to
* introduce the two in order to help you decide which one is more suitable
* for your application. You can also choose to use both interfaces in your
* application by considering each transfer on a case-by-case basis.
* Data will arrive when the button is pressed by the user, which is
* potentially hours later.
*
- * libusb offers both a synchronous and an asynchronous interface to performing
+ * libusbx offers both a synchronous and an asynchronous interface to performing
* USB transfers. The main difference is that the synchronous interface
* combines both steps indicated above into a single function call, whereas
* the asynchronous interface separates them.
* in the following style:
\code
unsigned char data[4];
-int actual_length,
-int r = libusb_bulk_transfer(handle, EP_IN, data, sizeof(data), &actual_length, 0);
+int actual_length;
+int r = libusb_bulk_transfer(handle, LIBUSB_ENDPOINT_IN, data, sizeof(data), &actual_length, 0);
if (r == 0 && actual_length == sizeof(data)) {
// results of the transaction can now be found in the data buffer
// parse them here and report button press
*
* For details on how to use the synchronous API, see the
* \ref syncio "synchronous I/O API documentation" pages.
- *
+ *
* \section async The asynchronous interface
*
* Asynchronous I/O is the most significant new feature in libusb-1.0.
* above.
*
* Instead of providing which functions that block until the I/O has complete,
- * libusb's asynchronous interface presents non-blocking functions which
+ * libusbx's asynchronous interface presents non-blocking functions which
* begin a transfer and then return immediately. Your application passes a
- * callback function pointer to this non-blocking function, which libusb will
+ * callback function pointer to this non-blocking function, which libusbx will
* call with the results of the transaction when it has completed.
*
* Transfers which have been submitted through the non-blocking functions
* to use threads.
*
* This added flexibility does come with some complications though:
- * - In the interest of being a lightweight library, libusb does not create
+ * - In the interest of being a lightweight library, libusbx does not create
* threads and can only operate when your application is calling into it. Your
- * application must call into libusb from it's main loop when events are ready
- * to be handled, or you must use some other scheme to allow libusb to
+ * application must call into libusbx from it's main loop when events are ready
+ * to be handled, or you must use some other scheme to allow libusbx to
* undertake whatever work needs to be done.
- * - libusb also needs to be called into at certain fixed points in time in
+ * - libusbx also needs to be called into at certain fixed points in time in
* order to accurately handle transfer timeouts.
* - Memory handling becomes more complex. You cannot use stack memory unless
* the function with that stack is guaranteed not to return until the transfer
* results are handled. This becomes particularly obvious when you want to
* submit a second transfer based on the results of an earlier transfer.
*
- * Internally, libusb's synchronous interface is expressed in terms of function
+ * Internally, libusbx's synchronous interface is expressed in terms of function
* calls to the asynchronous interface.
*
* For details on how to use the asynchronous API, see the
* constraints on packet size defined by endpoint descriptors. The host must
* not send data payloads larger than the endpoint's maximum packet size.
*
- * libusb and the underlying OS abstract out the packet concept, allowing you
+ * libusbx and the underlying OS abstract out the packet concept, allowing you
* to request transfers of any size. Internally, the request will be divided
* up into correctly-sized packets. You do not have to be concerned with
* packet sizes, but there is one exception when considering overflows.
*
* \section overflow Bulk/interrupt transfer overflows
*
- * When requesting data on a bulk endpoint, libusb requires you to supply a
- * buffer and the maximum number of bytes of data that libusb can put in that
+ * When requesting data on a bulk endpoint, libusbx requires you to supply a
+ * buffer and the maximum number of bytes of data that libusbx can put in that
* buffer. However, the size of the buffer is not communicated to the device -
* the device is just asked to send any amount of data.
*
* There is no problem if the device sends an amount of data that is less than
- * or equal to the buffer size. libusb reports this condition to you through
+ * or equal to the buffer size. libusbx reports this condition to you through
* the \ref libusb_transfer::actual_length "libusb_transfer.actual_length"
* field.
*
* Problems may occur if the device attempts to send more data than can fit in
- * the buffer. libusb reports LIBUSB_TRANSFER_OVERFLOW for this condition but
+ * the buffer. libusbx reports LIBUSB_TRANSFER_OVERFLOW for this condition but
* other behaviour is largely undefined: actual_length may or may not be
* accurate, the chunk of data that can fit in the buffer (before overflow)
* may or may not have been transferred.
/**
* @defgroup asyncio Asynchronous device I/O
*
- * This page details libusb's asynchronous (non-blocking) API for USB device
+ * This page details libusbx's asynchronous (non-blocking) API for USB device
* I/O. This interface is very powerful but is also quite complex - you will
* need to read this page carefully to understand the necessary considerations
* and issues surrounding use of this interface. Simplistic applications
*
* \section asyncabstraction Transfer abstraction
*
- * For the asynchronous I/O, libusb implements the concept of a generic
+ * For the asynchronous I/O, libusbx implements the concept of a generic
* transfer entity for all types of I/O (control, bulk, interrupt,
* isochronous). The generic transfer object must be treated slightly
* differently depending on which type of I/O you are performing with it.
* -# <b>Allocation</b>: allocate a libusb_transfer
* -# <b>Filling</b>: populate the libusb_transfer instance with information
* about the transfer you wish to perform
- * -# <b>Submission</b>: ask libusb to submit the transfer
+ * -# <b>Submission</b>: ask libusbx to submit the transfer
* -# <b>Completion handling</b>: examine transfer results in the
* libusb_transfer structure
* -# <b>Deallocation</b>: clean up resources
- *
+ *
*
* \subsection asyncalloc Allocation
*
*
* The user-specified callback is passed a pointer to the libusb_transfer
* structure which was used to setup and submit the transfer. At completion
- * time, libusb has populated this structure with results of the transfer:
+ * time, libusbx has populated this structure with results of the transfer:
* success or failure reason, number of bytes of data transferred, etc. See
* the libusb_transfer structure documentation for more information.
*
* Freeing the transfer after it has been cancelled but before cancellation
* has completed will result in undefined behaviour.
*
+ * When a transfer is cancelled, some of the data may have been transferred.
+ * libusbx will communicate this to you in the transfer callback. Do not assume
+ * that no data was transferred.
+ *
* \section bulk_overflows Overflows on device-to-host bulk/interrupt endpoints
*
* If your device does not have predictable transfer sizes (or it misbehaves),
* request was not supported.
*
* \section asyncintr Considerations for interrupt transfers
- *
+ *
* All interrupt transfers are performed using the polling interval presented
* by the bInterval value of the endpoint descriptor.
*
* Next, populate the length field for the first num_iso_packets entries in
* the \ref libusb_transfer::iso_packet_desc "iso_packet_desc" array. Section
* 5.6.3 of the USB2 specifications describe how the maximum isochronous
- * packet length is determined by wMaxPacketSize field in the endpoint
- * descriptor. Two functions can help you here:
- *
- * - libusb_get_max_packet_size() is an easy way to determine the max
- * packet size for an endpoint.
+ * packet length is determined by the wMaxPacketSize field in the endpoint
+ * descriptor.
+ * Two functions can help you here:
+ *
+ * - libusb_get_max_iso_packet_size() is an easy way to determine the max
+ * packet size for an isochronous endpoint. Note that the maximum packet
+ * size is actually the maximum number of bytes that can be transmitted in
+ * a single microframe, therefore this function multiplies the maximum number
+ * of bytes per transaction by the number of transaction opportunities per
+ * microframe.
* - libusb_set_iso_packet_lengths() assigns the same length to all packets
* within a transfer, which is usually what you want.
*
*
* In most circumstances, it is not safe to use stack memory for transfer
* buffers. This is because the function that fired off the asynchronous
- * transfer may return before libusb has finished using the buffer, and when
+ * transfer may return before libusbx has finished using the buffer, and when
* the function returns it's stack gets destroyed. This is true for both
* host-to-device and device-to-host transfers.
*
* \ref libusb_transfer_status::LIBUSB_TRANSFER_ERROR "LIBUSB_TRANSFER_ERROR"
* (they would normally be regarded as COMPLETED)
* - \ref libusb_transfer_flags::LIBUSB_TRANSFER_FREE_BUFFER
- * "LIBUSB_TRANSFER_FREE_BUFFER" allows you to ask libusb to free the transfer
+ * "LIBUSB_TRANSFER_FREE_BUFFER" allows you to ask libusbx to free the transfer
* buffer when freeing the transfer.
* - \ref libusb_transfer_flags::LIBUSB_TRANSFER_FREE_TRANSFER
- * "LIBUSB_TRANSFER_FREE_TRANSFER" causes libusb to automatically free the
+ * "LIBUSB_TRANSFER_FREE_TRANSFER" causes libusbx to automatically free the
* transfer after the transfer callback returns.
*
* \section asyncevent Event handling
*
- * In accordance of the aim of being a lightweight library, libusb does not
- * create threads internally. This means that libusb code does not execute
- * at any time other than when your application is calling a libusb function.
- * However, an asynchronous model requires that libusb perform work at various
+ * In accordance of the aim of being a lightweight library, libusbx does not
+ * create threads internally. This means that libusbx code does not execute
+ * at any time other than when your application is calling a libusbx function.
+ * However, an asynchronous model requires that libusbx perform work at various
* points in time - namely processing the results of previously-submitted
* transfers and invoking the user-supplied callback function.
*
* This gives rise to the libusb_handle_events() function which your
- * application must call into when libusb has work do to. This gives libusb
+ * application must call into when libusbx has work do to. This gives libusbx
* the opportunity to reap pending transfers, invoke callbacks, etc.
*
* The first issue to discuss here is how your application can figure out
- * when libusb has work to do. In fact, there are two naive options which
+ * when libusbx has work to do. In fact, there are two naive options which
* do not actually require your application to know this:
* -# Periodically call libusb_handle_events() in non-blocking mode at fixed
* short intervals from your main loop
* -# Repeatedly call libusb_handle_events() in blocking mode from a dedicated
* thread.
*
- * The first option is plainly not very nice, and will cause unnecessary
+ * The first option is plainly not very nice, and will cause unnecessary
* CPU wakeups leading to increased power usage and decreased battery life.
* The second option is not very nice either, but may be the nicest option
* available to you if the "proper" approach can not be applied to your
* application (read on...).
- *
- * The recommended option is to integrate libusb with your application main
- * event loop. libusb exposes a set of file descriptors which allow you to do
+ *
+ * The recommended option is to integrate libusbx with your application main
+ * event loop. libusbx exposes a set of file descriptors which allow you to do
* this. Your main loop is probably already calling poll() or select() or a
* variant on a set of file descriptors for other event sources (e.g. keyboard
* button presses, mouse movements, network sockets, etc). You then add
- * libusb's file descriptors to your poll()/select() calls, and when activity
+ * libusbx's file descriptors to your poll()/select() calls, and when activity
* is detected on such descriptors you know it is time to call
* libusb_handle_events().
*
- * There is one final event handling complication. libusb supports
+ * There is one final event handling complication. libusbx supports
* asynchronous transfers which time out after a specified time period, and
- * this requires that libusb is called into at or after the timeout so that
- * the timeout can be handled. So, in addition to considering libusb's file
- * descriptors in your main event loop, you must also consider that libusb
+ * this requires that libusbx is called into at or after the timeout so that
+ * the timeout can be handled. So, in addition to considering libusbx's file
+ * descriptors in your main event loop, you must also consider that libusbx
* sometimes needs to be called into at fixed points in time even when there
* is no file descriptor activity.
*
/**
* @defgroup poll Polling and timing
*
- * This page documents libusb's functions for polling events and timing.
+ * This page documents libusbx's functions for polling events and timing.
* These functions are only necessary for users of the
* \ref asyncio "asynchronous API". If you are only using the simpler
* \ref syncio "synchronous API" then you do not need to ever call these
*
* The justification for the functionality described here has already been
* discussed in the \ref asyncevent "event handling" section of the
- * asynchronous API documentation. In summary, libusb does not create internal
+ * asynchronous API documentation. In summary, libusbx does not create internal
* threads for event processing and hence relies on your application calling
- * into libusb at certain points in time so that pending events can be handled.
- * In order to know precisely when libusb needs to be called into, libusb
+ * into libusbx at certain points in time so that pending events can be handled.
+ * In order to know precisely when libusbx needs to be called into, libusbx
* offers you a set of pollable file descriptors and information about when
* the next timeout expires.
*
*
* \section pollsimple The simple option
*
- * If your application revolves solely around libusb and does not need to
+ * If your application revolves solely around libusbx and does not need to
* handle other event sources, you can have a program structure as follows:
\code
-// initialize libusb
+// initialize libusbx
// find and open device
// maybe fire off some initial async I/O
*
* \section pollmain The more advanced option
*
+ * \note This functionality is currently only available on Unix-like platforms.
+ * On Windows, libusb_get_pollfds() simply returns NULL. Exposing event sources
+ * on Windows will require some further thought and design.
+ *
* In more advanced applications, you will already have a main loop which
* is monitoring other event sources: network sockets, X11 events, mouse
- * movements, etc. Through exposing a set of file descriptors, libusb is
+ * movements, etc. Through exposing a set of file descriptors, libusbx is
* designed to cleanly integrate into such main loops.
*
* In addition to polling file descriptors for the other event sources, you
- * take a set of file descriptors from libusb and monitor those too. When you
- * detect activity on libusb's file descriptors, you call
+ * take a set of file descriptors from libusbx and monitor those too. When you
+ * detect activity on libusbx's file descriptors, you call
* libusb_handle_events_timeout() in non-blocking mode.
*
- * You must also consider the fact that libusb sometimes has to handle events
- * at certain known times which do not generate activity on file descriptors.
- * Your main loop must also consider these times, modify it's poll()/select()
- * timeout accordingly, and track time so that libusb_handle_events_timeout()
- * is called in non-blocking mode when timeouts expire.
+ * What's more, libusbx may also need to handle events at specific moments in
+ * time. No file descriptor activity is generated at these times, so your
+ * own application needs to be continually aware of when the next one of these
+ * moments occurs (through calling libusb_get_next_timeout()), and then it
+ * needs to call libusb_handle_events_timeout() in non-blocking mode when
+ * these moments occur. This means that you need to adjust your
+ * poll()/select() timeout accordingly.
+ *
+ * libusbx provides you with a set of file descriptors to poll and expects you
+ * to poll all of them, treating them as a single entity. The meaning of each
+ * file descriptor in the set is an internal implementation detail,
+ * platform-dependent and may vary from release to release. Don't try and
+ * interpret the meaning of the file descriptors, just do as libusbx indicates,
+ * polling all of them at once.
*
* In pseudo-code, you want something that looks like:
\code
-// initialise libusb
+// initialise libusbx
libusb_get_pollfds(ctx)
while (user has not requested application exit) {
libusb_get_next_timeout(ctx);
- select(on libusb file descriptors plus any other event sources of interest,
- using a timeout no larger than the value libusb just suggested)
- if (select() indicated activity on libusb file descriptors)
- libusb_handle_events_timeout(ctx, 0);
- if (time has elapsed to or beyond the libusb timeout)
- libusb_handle_events_timeout(ctx, 0);
+ poll(on libusbx file descriptors plus any other event sources of interest,
+ using a timeout no larger than the value libusbx just suggested)
+ if (poll() indicated activity on libusbx file descriptors)
+ libusb_handle_events_timeout(ctx, &zero_tv);
+ if (time has elapsed to or beyond the libusbx timeout)
+ libusb_handle_events_timeout(ctx, &zero_tv);
+ // handle events from other sources here
}
// clean up and exit
\endcode
*
- * The set of file descriptors that libusb uses as event sources may change
+ * \subsection polltime Notes on time-based events
+ *
+ * The above complication with having to track time and call into libusbx at
+ * specific moments is a bit of a headache. For maximum compatibility, you do
+ * need to write your main loop as above, but you may decide that you can
+ * restrict the supported platforms of your application and get away with
+ * a more simplistic scheme.
+ *
+ * These time-based event complications are \b not required on the following
+ * platforms:
+ * - Darwin
+ * - Linux, provided that the following version requirements are satisfied:
+ * - Linux v2.6.27 or newer, compiled with timerfd support
+ * - glibc v2.9 or newer
+ * - libusbx v1.0.5 or newer
+ *
+ * Under these configurations, libusb_get_next_timeout() will \em always return
+ * 0, so your main loop can be simplified to:
+\code
+// initialise libusbx
+
+libusb_get_pollfds(ctx)
+while (user has not requested application exit) {
+ poll(on libusbx file descriptors plus any other event sources of interest,
+ using any timeout that you like)
+ if (poll() indicated activity on libusbx file descriptors)
+ libusb_handle_events_timeout(ctx, &zero_tv);
+ // handle events from other sources here
+}
+
+// clean up and exit
+\endcode
+ *
+ * Do remember that if you simplify your main loop to the above, you will
+ * lose compatibility with some platforms (including legacy Linux platforms,
+ * and <em>any future platforms supported by libusbx which may have time-based
+ * event requirements</em>). The resultant problems will likely appear as
+ * strange bugs in your application.
+ *
+ * You can use the libusb_pollfds_handle_timeouts() function to do a runtime
+ * check to see if it is safe to ignore the time-based event complications.
+ * If your application has taken the shortcut of ignoring libusbx's next timeout
+ * in your main loop, then you are advised to check the return value of
+ * libusb_pollfds_handle_timeouts() during application startup, and to abort
+ * if the platform does suffer from these timing complications.
+ *
+ * \subsection fdsetchange Changes in the file descriptor set
+ *
+ * The set of file descriptors that libusbx uses as event sources may change
* during the life of your application. Rather than having to repeatedly
* call libusb_get_pollfds(), you can set up notification functions for when
* the file descriptor set changes using libusb_set_pollfd_notifiers().
*
- * \section mtissues Multi-threaded considerations
+ * \subsection mtissues Multi-threaded considerations
*
* Unfortunately, the situation is complicated further when multiple threads
* come into play. If two threads are monitoring the same file descriptors,
/** \page mtasync Multi-threaded applications and asynchronous I/O
*
- * libusb is a thread-safe library, but extra considerations must be applied
- * to applications which interact with libusb from multiple threads.
+ * libusbx is a thread-safe library, but extra considerations must be applied
+ * to applications which interact with libusbx from multiple threads.
*
- * The underlying issue that must be addressed is that all libusb I/O
+ * The underlying issue that must be addressed is that all libusbx I/O
* revolves around monitoring file descriptors through the poll()/select()
* system calls. This is directly exposed at the
* \ref asyncio "asynchronous interface" but it is important to note that the
* asynchonrous interface, therefore the same considerations apply.
*
* The issue is that if two or more threads are concurrently calling poll()
- * or select() on libusb's file descriptors then only one of those threads
+ * or select() on libusbx's file descriptors then only one of those threads
* will be woken up when an event arrives. The others will be completely
* oblivious that anything has happened.
*
* Consider the following pseudo-code, which submits an asynchronous transfer
* then waits for its completion. This style is one way you could implement a
- * synchronous interface on top of the asynchronous interface (and libusb
+ * synchronous interface on top of the asynchronous interface (and libusbx
* does something similar, albeit more advanced due to the complications
* explained on this page).
*
libusb_submit_transfer(transfer);
while (!completed) {
- poll(libusb file descriptors, 120*1000);
+ poll(libusbx file descriptors, 120*1000);
if (poll indicates activity)
- libusb_handle_events_timeout(ctx, 0);
+ libusb_handle_events_timeout(ctx, &zero_tv);
}
printf("completed!");
// other code here
* The poll() loop has a long timeout to minimize CPU usage during situations
* when nothing is happening (it could reasonably be unlimited).
*
- * If this is the only thread that is polling libusb's file descriptors, there
+ * If this is the only thread that is polling libusbx's file descriptors, there
* is no problem: there is no danger that another thread will swallow up the
* event that we are interested in. On the other hand, if there is another
* thread polling the same descriptors, there is a chance that it will receive
* the loop, <em>up to 120 seconds later.</em> Clearly a two-minute delay is
* undesirable, and don't even think about using short timeouts to circumvent
* this issue!
- *
+ *
* The solution here is to ensure that no two threads are ever polling the
* file descriptors at the same time. A naive implementation of this would
- * impact the capabilities of the library, so libusb offers the scheme
+ * impact the capabilities of the library, so libusbx offers the scheme
* documented below to ensure no loss of functionality.
*
* Before we go any further, it is worth mentioning that all libusb-wrapped
* event handling procedures fully adhere to the scheme documented below.
- * This includes libusb_handle_events() and all the synchronous I/O functions -
- * libusb hides this headache from you. You do not need to worry about any
- * of these issues if you stick to that level.
+ * This includes libusb_handle_events() and its variants, and all the
+ * synchronous I/O functions - libusbx hides this headache from you.
+ *
+ * \section Using libusb_handle_events() from multiple threads
+ *
+ * Even when only using libusb_handle_events() and synchronous I/O functions,
+ * you can still have a race condition. You might be tempted to solve the
+ * above with libusb_handle_events() like so:
*
- * The problem is when we consider the fact that libusb exposes file
+\code
+ libusb_submit_transfer(transfer);
+
+ while (!completed) {
+ libusb_handle_events(ctx);
+ }
+ printf("completed!");
+\endcode
+ *
+ * This however has a race between the checking of completed and
+ * libusb_handle_events() acquiring the events lock, so another thread
+ * could have completed the transfer, resulting in this thread hanging
+ * until either a timeout or another event occurs. See also commit
+ * 6696512aade99bb15d6792af90ae329af270eba6 which fixes this in the
+ * synchronous API implementation of libusb.
+ *
+ * Fixing this race requires checking the variable completed only after
+ * taking the event lock, which defeats the concept of just calling
+ * libusb_handle_events() without worrying about locking. This is why
+ * libusb-1.0.9 introduces the new libusb_handle_events_timeout_completed()
+ * and libusb_handle_events_completed() functions, which handles doing the
+ * completion check for you after they have acquired the lock:
+ *
+\code
+ libusb_submit_transfer(transfer);
+
+ while (!completed) {
+ libusb_handle_events_completed(ctx, &completed);
+ }
+ printf("completed!");
+\endcode
+ *
+ * This nicely fixes the race in our example. Note that if all you want to
+ * do is submit a single transfer and wait for its completion, then using
+ * one of the synchronous I/O functions is much easier.
+ *
+ * \section eventlock The events lock
+ *
+ * The problem is when we consider the fact that libusbx exposes file
* descriptors to allow for you to integrate asynchronous USB I/O into
* existing main loops, effectively allowing you to do some work behind
- * libusb's back. If you do take libusb's file descriptors and pass them to
+ * libusbx's back. If you do take libusbx's file descriptors and pass them to
* poll()/select() yourself, you need to be aware of the associated issues.
*
- * \section eventlock The events lock
- *
* The first concept to be introduced is the events lock. The events lock
* is used to serialize threads that want to handle events, such that only
* one thread is handling events at any one time.
*
- * You must take the events lock before polling libusb file descriptors,
+ * You must take the events lock before polling libusbx file descriptors,
* using libusb_lock_events(). You must release the lock as soon as you have
* aborted your poll()/select() loop, using libusb_unlock_events().
*
\code
libusb_lock_events(ctx);
while (!completed) {
- poll(libusb file descriptors, 120*1000);
+ poll(libusbx file descriptors, 120*1000);
if (poll indicates activity)
- libusb_handle_events_timeout(ctx, 0);
+ libusb_handle_events_timeout(ctx, &zero_tv);
}
libusb_unlock_events(ctx);
\endcode
* status of its transfer until the code above has finished (30 seconds later)
* due to contention on the lock.
*
- * To solve this, libusb offers you a mechanism to determine when another
+ * To solve this, libusbx offers you a mechanism to determine when another
* thread is handling events. It also offers a mechanism to block your thread
* until the event handling thread has completed an event (and this mechanism
* does not involve polling of file descriptors).
libusb_unlock_events(ctx);
goto retry;
}
- poll(libusb file descriptors, 120*1000);
+ poll(libusbx file descriptors, 120*1000);
if (poll indicates activity)
libusb_handle_events_locked(ctx, 0);
}
libusb_unlock_event_waiters(ctx);
goto retry;
}
-
- libusb_wait_for_event(ctx);
+
+ libusb_wait_for_event(ctx, NULL);
}
libusb_unlock_event_waiters(ctx);
}
* should be apparent from the code shown above.
* -# libusb_try_lock_events() is a non-blocking function which attempts
* to acquire the events lock but returns a failure code if it is contended.
- * -# libusb_event_handling_ok() checks that libusb is still happy for your
- * thread to be performing event handling. Sometimes, libusb needs to
+ * -# libusb_event_handling_ok() checks that libusbx is still happy for your
+ * thread to be performing event handling. Sometimes, libusbx needs to
* interrupt the event handler, and this is how you can check if you have
* been interrupted. If this function returns 0, the correct behaviour is
* for you to give up the event handling lock, and then to repeat the cycle.
* libusb_handle_events_timeout() that you can call while holding the
* events lock. libusb_handle_events_timeout() itself implements similar
* logic to the above, so be sure not to call it when you are
- * "working behind libusb's back", as is the case here.
+ * "working behind libusbx's back", as is the case here.
* -# libusb_event_handler_active() determines if someone is currently
* holding the events lock
*
* You might be wondering why there is no function to wake up all threads
- * blocked on libusb_wait_for_event(). This is because libusb can do this
+ * blocked on libusb_wait_for_event(). This is because libusbx can do this
* internally: it will wake up all such threads when someone calls
* libusb_unlock_events() or when a transfer completes (at the point after its
* callback has returned).
*
* The above explanation should be enough to get you going, but if you're
* really thinking through the issues then you may be left with some more
- * questions regarding libusb's internals. If you're curious, read on, and if
+ * questions regarding libusbx's internals. If you're curious, read on, and if
* not, skip to the next section to avoid confusing yourself!
*
* The immediate question that may spring to mind is: what if one thread
* are all kinds of race conditions that could arise here, so it is
* important that nobody is doing event handling at this time.
*
- * libusb handles these issues internally, so application developers do not
+ * libusbx handles these issues internally, so application developers do not
* have to stop their event handlers while opening/closing devices. Here's how
* it works, focusing on the libusb_close() situation first:
*
- * -# During initialization, libusb opens an internal pipe, and it adds the read
+ * -# During initialization, libusbx opens an internal pipe, and it adds the read
* end of this pipe to the set of file descriptors to be polled.
- * -# During libusb_close(), libusb writes some dummy data on this control pipe.
- * This immediately interrupts the event handler. libusb also records
+ * -# During libusb_close(), libusbx writes some dummy data on this control pipe.
+ * This immediately interrupts the event handler. libusbx also records
* internally that it is trying to interrupt event handlers for this
* high-priority event.
* -# At this point, some of the functions described above start behaving
* giving up the events lock very quickly, giving the high-priority
* libusb_close() operation a "free ride" to acquire the events lock. All
* threads that are competing to do event handling become event waiters.
- * -# With the events lock held inside libusb_close(), libusb can safely remove
+ * -# With the events lock held inside libusb_close(), libusbx can safely remove
* a file descriptor from the poll set, in the safety of knowledge that
* nobody is polling those descriptors or trying to access the poll set.
* -# After obtaining the events lock, the close operation completes very
* call to libusb_open():
*
* -# The device is opened and a file descriptor is added to the poll set.
- * -# libusb sends some dummy data on the control pipe, and records that it
+ * -# libusbx sends some dummy data on the control pipe, and records that it
* is trying to modify the poll descriptor set.
* -# The event handler is interrupted, and the same behaviour change as for
* libusb_close() takes effect, causing all event handling threads to become
*
* The above may seem a little complicated, but hopefully I have made it clear
* why such complications are necessary. Also, do not forget that this only
- * applies to applications that take libusb's file descriptors and integrate
+ * applies to applications that take libusbx's file descriptors and integrate
* them into their own polling loops.
*
* You may decide that it is OK for your multi-threaded application to ignore
{
int r;
- pthread_mutex_init(&ctx->flying_transfers_lock, NULL);
- pthread_mutex_init(&ctx->pollfds_lock, NULL);
- pthread_mutex_init(&ctx->pollfd_modify_lock, NULL);
- pthread_mutex_init(&ctx->events_lock, NULL);
- pthread_mutex_init(&ctx->event_waiters_lock, NULL);
- pthread_cond_init(&ctx->event_waiters_cond, NULL);
+ usbi_mutex_init(&ctx->flying_transfers_lock, NULL);
+ usbi_mutex_init(&ctx->pollfds_lock, NULL);
+ usbi_mutex_init(&ctx->pollfd_modify_lock, NULL);
+ usbi_mutex_init_recursive(&ctx->events_lock, NULL);
+ usbi_mutex_init(&ctx->event_waiters_lock, NULL);
+ usbi_cond_init(&ctx->event_waiters_cond, NULL);
list_init(&ctx->flying_transfers);
list_init(&ctx->pollfds);
/* FIXME should use an eventfd on kernels that support it */
- r = pipe(ctx->ctrl_pipe);
- if (r < 0)
- return LIBUSB_ERROR_OTHER;
+ r = usbi_pipe(ctx->ctrl_pipe);
+ if (r < 0) {
+ r = LIBUSB_ERROR_OTHER;
+ goto err;
+ }
r = usbi_add_pollfd(ctx, ctx->ctrl_pipe[0], POLLIN);
if (r < 0)
- return r;
+ goto err_close_pipe;
+
+#ifdef USBI_TIMERFD_AVAILABLE
+ ctx->timerfd = timerfd_create(usbi_backend->get_timerfd_clockid(),
+ TFD_NONBLOCK);
+ if (ctx->timerfd >= 0) {
+ usbi_dbg("using timerfd for timeouts");
+ r = usbi_add_pollfd(ctx, ctx->timerfd, POLLIN);
+ if (r < 0) {
+ usbi_remove_pollfd(ctx, ctx->ctrl_pipe[0]);
+ close(ctx->timerfd);
+ goto err_close_pipe;
+ }
+ } else {
+ usbi_dbg("timerfd not available (code %d error %d)", ctx->timerfd, errno);
+ ctx->timerfd = -1;
+ }
+#endif
return 0;
+
+err_close_pipe:
+ usbi_close(ctx->ctrl_pipe[0]);
+ usbi_close(ctx->ctrl_pipe[1]);
+err:
+ usbi_mutex_destroy(&ctx->flying_transfers_lock);
+ usbi_mutex_destroy(&ctx->pollfds_lock);
+ usbi_mutex_destroy(&ctx->pollfd_modify_lock);
+ usbi_mutex_destroy(&ctx->events_lock);
+ usbi_mutex_destroy(&ctx->event_waiters_lock);
+ usbi_cond_destroy(&ctx->event_waiters_cond);
+ return r;
}
void usbi_io_exit(struct libusb_context *ctx)
{
usbi_remove_pollfd(ctx, ctx->ctrl_pipe[0]);
- close(ctx->ctrl_pipe[0]);
- close(ctx->ctrl_pipe[1]);
+ usbi_close(ctx->ctrl_pipe[0]);
+ usbi_close(ctx->ctrl_pipe[1]);
+#ifdef USBI_TIMERFD_AVAILABLE
+ if (usbi_using_timerfd(ctx)) {
+ usbi_remove_pollfd(ctx, ctx->timerfd);
+ close(ctx->timerfd);
+ }
+#endif
+ usbi_mutex_destroy(&ctx->flying_transfers_lock);
+ usbi_mutex_destroy(&ctx->pollfds_lock);
+ usbi_mutex_destroy(&ctx->pollfd_modify_lock);
+ usbi_mutex_destroy(&ctx->events_lock);
+ usbi_mutex_destroy(&ctx->event_waiters_lock);
+ usbi_cond_destroy(&ctx->event_waiters_cond);
}
static int calculate_timeout(struct usbi_transfer *transfer)
int r;
struct timespec current_time;
unsigned int timeout =
- __USBI_TRANSFER_TO_LIBUSB_TRANSFER(transfer)->timeout;
+ USBI_TRANSFER_TO_LIBUSB_TRANSFER(transfer)->timeout;
if (!timeout)
return 0;
- r = clock_gettime(CLOCK_MONOTONIC, ¤t_time);
+ r = usbi_backend->clock_gettime(USBI_CLOCK_MONOTONIC, ¤t_time);
if (r < 0) {
usbi_err(ITRANSFER_CTX(transfer),
"failed to read monotonic clock, errno=%d", errno);
return 0;
}
-static void add_to_flying_list(struct usbi_transfer *transfer)
+/* add a transfer to the (timeout-sorted) active transfers list.
+ * returns 1 if the transfer has a timeout and it is the timeout next to
+ * expire */
+static int add_to_flying_list(struct usbi_transfer *transfer)
{
struct usbi_transfer *cur;
struct timeval *timeout = &transfer->timeout;
struct libusb_context *ctx = ITRANSFER_CTX(transfer);
-
- pthread_mutex_lock(&ctx->flying_transfers_lock);
+ int r = 0;
+ int first = 1;
+
+ usbi_mutex_lock(&ctx->flying_transfers_lock);
/* if we have no other flying transfers, start the list with this one */
if (list_empty(&ctx->flying_transfers)) {
/* if we have infinite timeout, append to end of list */
if (!timerisset(timeout)) {
list_add_tail(&transfer->list, &ctx->flying_transfers);
+ /* first is irrelevant in this case */
goto out;
}
/* otherwise, find appropriate place in list */
- list_for_each_entry(cur, &ctx->flying_transfers, list) {
+ list_for_each_entry(cur, &ctx->flying_transfers, list, struct usbi_transfer) {
/* find first timeout that occurs after the transfer in question */
struct timeval *cur_tv = &cur->timeout;
list_add_tail(&transfer->list, &cur->list);
goto out;
}
+ first = 0;
}
+ /* first is 0 at this stage (list not empty) */
/* otherwise we need to be inserted at the end */
list_add_tail(&transfer->list, &ctx->flying_transfers);
out:
- pthread_mutex_unlock(&ctx->flying_transfers_lock);
+#ifdef USBI_TIMERFD_AVAILABLE
+ if (first && usbi_using_timerfd(ctx) && timerisset(timeout)) {
+ /* if this transfer has the lowest timeout of all active transfers,
+ * rearm the timerfd with this transfer's timeout */
+ const struct itimerspec it = { {0, 0},
+ { transfer->timeout.tv_sec, transfer->timeout.tv_usec * 1000 } };
+ usbi_dbg("arm timerfd for timeout in %dms (first in line)",
+ USBI_TRANSFER_TO_LIBUSB_TRANSFER(transfer)->timeout);
+ r = timerfd_settime(ctx->timerfd, TFD_TIMER_ABSTIME, &it, NULL);
+ if (r < 0) {
+ usbi_warn(ctx, "failed to arm first timerfd (error %d)", r);
+ r = LIBUSB_ERROR_OTHER;
+ }
+ }
+#else
+ UNUSED(first);
+#endif
+
+ usbi_mutex_unlock(&ctx->flying_transfers_lock);
+ return r;
}
/** \ingroup asyncio
- * Allocate a libusb transfer with a specified number of isochronous packet
+ * Allocate a libusbx transfer with a specified number of isochronous packet
* descriptors. The returned transfer is pre-initialized for you. When the new
* transfer is no longer needed, it should be freed with
* libusb_free_transfer().
* \param iso_packets number of isochronous packet descriptors to allocate
* \returns a newly allocated transfer, or NULL on error
*/
-API_EXPORTED struct libusb_transfer *libusb_alloc_transfer(int iso_packets)
+DEFAULT_VISIBILITY
+struct libusb_transfer * LIBUSB_CALL libusb_alloc_transfer(
+ int iso_packets)
{
size_t os_alloc_size = usbi_backend->transfer_priv_size
+ (usbi_backend->add_iso_packet_size * iso_packets);
- int alloc_size = sizeof(struct usbi_transfer)
+ size_t alloc_size = sizeof(struct usbi_transfer)
+ sizeof(struct libusb_transfer)
+ (sizeof(struct libusb_iso_packet_descriptor) * iso_packets)
+ os_alloc_size;
- struct usbi_transfer *itransfer = malloc(alloc_size);
+ struct usbi_transfer *itransfer = calloc(1, alloc_size);
if (!itransfer)
return NULL;
- memset(itransfer, 0, alloc_size);
itransfer->num_iso_packets = iso_packets;
- return __USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
+ usbi_mutex_init(&itransfer->lock, NULL);
+ return USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
}
/** \ingroup asyncio
* It is legal to call this function with a NULL transfer. In this case,
* the function will simply return safely.
*
+ * It is not legal to free an active transfer (one which has been submitted
+ * and has not yet completed).
+ *
* \param transfer the transfer to free
*/
-API_EXPORTED void libusb_free_transfer(struct libusb_transfer *transfer)
+void API_EXPORTED libusb_free_transfer(struct libusb_transfer *transfer)
{
struct usbi_transfer *itransfer;
if (!transfer)
if (transfer->flags & LIBUSB_TRANSFER_FREE_BUFFER && transfer->buffer)
free(transfer->buffer);
- itransfer = __LIBUSB_TRANSFER_TO_USBI_TRANSFER(transfer);
+ itransfer = LIBUSB_TRANSFER_TO_USBI_TRANSFER(transfer);
+ usbi_mutex_destroy(&itransfer->lock);
free(itransfer);
}
+#ifdef USBI_TIMERFD_AVAILABLE
+static int disarm_timerfd(struct libusb_context *ctx)
+{
+ const struct itimerspec disarm_timer = { { 0, 0 }, { 0, 0 } };
+ int r;
+
+ usbi_dbg("");
+ r = timerfd_settime(ctx->timerfd, 0, &disarm_timer, NULL);
+ if (r < 0)
+ return LIBUSB_ERROR_OTHER;
+ else
+ return 0;
+}
+
+/* iterates through the flying transfers, and rearms the timerfd based on the
+ * next upcoming timeout.
+ * must be called with flying_list locked.
+ * returns 0 if there was no timeout to arm, 1 if the next timeout was armed,
+ * or a LIBUSB_ERROR code on failure.
+ */
+static int arm_timerfd_for_next_timeout(struct libusb_context *ctx)
+{
+ struct usbi_transfer *transfer;
+
+ list_for_each_entry(transfer, &ctx->flying_transfers, list, struct usbi_transfer) {
+ struct timeval *cur_tv = &transfer->timeout;
+
+ /* if we've reached transfers of infinite timeout, then we have no
+ * arming to do */
+ if (!timerisset(cur_tv))
+ goto disarm;
+
+ /* act on first transfer that is not already cancelled */
+ if (!(transfer->flags & USBI_TRANSFER_TIMED_OUT)) {
+ int r;
+ const struct itimerspec it = { {0, 0},
+ { cur_tv->tv_sec, cur_tv->tv_usec * 1000 } };
+ usbi_dbg("next timeout originally %dms", USBI_TRANSFER_TO_LIBUSB_TRANSFER(transfer)->timeout);
+ r = timerfd_settime(ctx->timerfd, TFD_TIMER_ABSTIME, &it, NULL);
+ if (r < 0)
+ return LIBUSB_ERROR_OTHER;
+ return 1;
+ }
+ }
+
+disarm:
+ return disarm_timerfd(ctx);
+}
+#else
+static int arm_timerfd_for_next_timeout(struct libusb_context *ctx)
+{
+ (void)ctx;
+ return 0;
+}
+#endif
+
/** \ingroup asyncio
* Submit a transfer. This function will fire off the USB transfer and then
* return immediately.
* \returns 0 on success
* \returns LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
* \returns LIBUSB_ERROR_BUSY if the transfer has already been submitted.
+ * \returns LIBUSB_ERROR_NOT_SUPPORTED if the transfer flags are not supported
+ * by the operating system.
* \returns another LIBUSB_ERROR code on other failure
*/
-API_EXPORTED int libusb_submit_transfer(struct libusb_transfer *transfer)
+int API_EXPORTED libusb_submit_transfer(struct libusb_transfer *transfer)
{
+ struct libusb_context *ctx = TRANSFER_CTX(transfer);
struct usbi_transfer *itransfer =
- __LIBUSB_TRANSFER_TO_USBI_TRANSFER(transfer);
+ LIBUSB_TRANSFER_TO_USBI_TRANSFER(transfer);
int r;
+ int updated_fds;
+ usbi_mutex_lock(&itransfer->lock);
itransfer->transferred = 0;
itransfer->flags = 0;
r = calculate_timeout(itransfer);
- if (r < 0)
- return LIBUSB_ERROR_OTHER;
+ if (r < 0) {
+ r = LIBUSB_ERROR_OTHER;
+ goto out;
+ }
- add_to_flying_list(itransfer);
+ r = add_to_flying_list(itransfer);
+ if (r)
+ goto out;
r = usbi_backend->submit_transfer(itransfer);
if (r) {
- pthread_mutex_lock(&TRANSFER_CTX(transfer)->flying_transfers_lock);
+ usbi_mutex_lock(&ctx->flying_transfers_lock);
list_del(&itransfer->list);
- pthread_mutex_unlock(&TRANSFER_CTX(transfer)->flying_transfers_lock);
+ arm_timerfd_for_next_timeout(ctx);
+ usbi_mutex_unlock(&ctx->flying_transfers_lock);
}
+out:
+ updated_fds = (itransfer->flags & USBI_TRANSFER_UPDATED_FDS);
+ usbi_mutex_unlock(&itransfer->lock);
+ if (updated_fds)
+ usbi_fd_notification(ctx);
return r;
}
* cancelled.
* \returns a LIBUSB_ERROR code on failure
*/
-API_EXPORTED int libusb_cancel_transfer(struct libusb_transfer *transfer)
+int API_EXPORTED libusb_cancel_transfer(struct libusb_transfer *transfer)
{
struct usbi_transfer *itransfer =
- __LIBUSB_TRANSFER_TO_USBI_TRANSFER(transfer);
+ LIBUSB_TRANSFER_TO_USBI_TRANSFER(transfer);
int r;
usbi_dbg("");
+ usbi_mutex_lock(&itransfer->lock);
r = usbi_backend->cancel_transfer(itransfer);
- if (r < 0)
- usbi_err(TRANSFER_CTX(transfer),
- "cancel transfer failed error %d", r);
+ if (r < 0) {
+ if (r != LIBUSB_ERROR_NOT_FOUND)
+ usbi_err(TRANSFER_CTX(transfer),
+ "cancel transfer failed error %d", r);
+ else
+ usbi_dbg("cancel transfer failed error %d", r);
+
+ if (r == LIBUSB_ERROR_NO_DEVICE)
+ itransfer->flags |= USBI_TRANSFER_DEVICE_DISAPPEARED;
+ }
+
+ itransfer->flags |= USBI_TRANSFER_CANCELLING;
+
+ usbi_mutex_unlock(&itransfer->lock);
return r;
}
* This will invoke the user-supplied callback function, which may end up
* freeing the transfer. Therefore you cannot use the transfer structure
* after calling this function, and you should free all backend-specific
- * data before calling it. */
-void usbi_handle_transfer_completion(struct usbi_transfer *itransfer,
+ * data before calling it.
+ * Do not call this function with the usbi_transfer lock held. User-specified
+ * callback functions may attempt to directly resubmit the transfer, which
+ * will attempt to take the lock. */
+int usbi_handle_transfer_completion(struct usbi_transfer *itransfer,
enum libusb_transfer_status status)
{
struct libusb_transfer *transfer =
- __USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
+ USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
struct libusb_context *ctx = TRANSFER_CTX(transfer);
uint8_t flags;
+ int r = 0;
+
+ /* FIXME: could be more intelligent with the timerfd here. we don't need
+ * to disarm the timerfd if there was no timer running, and we only need
+ * to rearm the timerfd if the transfer that expired was the one with
+ * the shortest timeout. */
- pthread_mutex_lock(&ctx->flying_transfers_lock);
+ usbi_mutex_lock(&ctx->flying_transfers_lock);
list_del(&itransfer->list);
- pthread_mutex_unlock(&ctx->flying_transfers_lock);
+ if (usbi_using_timerfd(ctx))
+ r = arm_timerfd_for_next_timeout(ctx);
+ usbi_mutex_unlock(&ctx->flying_transfers_lock);
+ if (usbi_using_timerfd(ctx) && (r < 0))
+ return r;
if (status == LIBUSB_TRANSFER_COMPLETED
&& transfer->flags & LIBUSB_TRANSFER_SHORT_NOT_OK) {
flags = transfer->flags;
transfer->status = status;
transfer->actual_length = itransfer->transferred;
+ usbi_dbg("transfer %p has callback %p", transfer, transfer->callback);
if (transfer->callback)
transfer->callback(transfer);
/* transfer might have been freed by the above call, do not use from
* this point. */
if (flags & LIBUSB_TRANSFER_FREE_TRANSFER)
libusb_free_transfer(transfer);
- pthread_mutex_lock(&ctx->event_waiters_lock);
- pthread_cond_broadcast(&ctx->event_waiters_cond);
- pthread_mutex_unlock(&ctx->event_waiters_lock);
+ usbi_mutex_lock(&ctx->event_waiters_lock);
+ usbi_cond_broadcast(&ctx->event_waiters_cond);
+ usbi_mutex_unlock(&ctx->event_waiters_lock);
+ return 0;
}
/* Similar to usbi_handle_transfer_completion() but exclusively for transfers
* that were asynchronously cancelled. The same concerns w.r.t. freeing of
* transfers exist here.
- */
-void usbi_handle_transfer_cancellation(struct usbi_transfer *transfer)
+ * Do not call this function with the usbi_transfer lock held. User-specified
+ * callback functions may attempt to directly resubmit the transfer, which
+ * will attempt to take the lock. */
+int usbi_handle_transfer_cancellation(struct usbi_transfer *transfer)
{
/* if the URB was cancelled due to timeout, report timeout to the user */
if (transfer->flags & USBI_TRANSFER_TIMED_OUT) {
usbi_dbg("detected timeout cancellation");
- usbi_handle_transfer_completion(transfer, LIBUSB_TRANSFER_TIMED_OUT);
- return;
+ return usbi_handle_transfer_completion(transfer, LIBUSB_TRANSFER_TIMED_OUT);
}
/* otherwise its a normal async cancel */
- usbi_handle_transfer_completion(transfer, LIBUSB_TRANSFER_CANCELLED);
+ return usbi_handle_transfer_completion(transfer, LIBUSB_TRANSFER_CANCELLED);
}
/** \ingroup poll
* Attempt to acquire the event handling lock. This lock is used to ensure that
- * only one thread is monitoring libusb event sources at any one time.
+ * only one thread is monitoring libusbx event sources at any one time.
*
* You only need to use this lock if you are developing an application
- * which calls poll() or select() on libusb's file descriptors directly.
- * If you stick to libusb's event handling loop functions (e.g.
+ * which calls poll() or select() on libusbx's file descriptors directly.
+ * If you stick to libusbx's event handling loop functions (e.g.
* libusb_handle_events()) then you do not need to be concerned with this
* locking.
*
* \returns 1 if the lock was not obtained (i.e. another thread holds the lock)
* \see \ref mtasync
*/
-API_EXPORTED int libusb_try_lock_events(libusb_context *ctx)
+int API_EXPORTED libusb_try_lock_events(libusb_context *ctx)
{
int r;
USBI_GET_CONTEXT(ctx);
/* is someone else waiting to modify poll fds? if so, don't let this thread
* start event handling */
- pthread_mutex_lock(&ctx->pollfd_modify_lock);
+ usbi_mutex_lock(&ctx->pollfd_modify_lock);
r = ctx->pollfd_modify;
- pthread_mutex_unlock(&ctx->pollfd_modify_lock);
+ usbi_mutex_unlock(&ctx->pollfd_modify_lock);
if (r) {
usbi_dbg("someone else is modifying poll fds");
return 1;
}
- r = pthread_mutex_trylock(&ctx->events_lock);
+ r = usbi_mutex_trylock(&ctx->events_lock);
if (r)
return 1;
- ctx->event_handler_active = 1;
+ ctx->event_handler_active = 1;
return 0;
}
/** \ingroup poll
* Acquire the event handling lock, blocking until successful acquisition if
* it is contended. This lock is used to ensure that only one thread is
- * monitoring libusb event sources at any one time.
+ * monitoring libusbx event sources at any one time.
*
* You only need to use this lock if you are developing an application
- * which calls poll() or select() on libusb's file descriptors directly.
- * If you stick to libusb's event handling loop functions (e.g.
+ * which calls poll() or select() on libusbx's file descriptors directly.
+ * If you stick to libusbx's event handling loop functions (e.g.
* libusb_handle_events()) then you do not need to be concerned with this
* locking.
*
* \param ctx the context to operate on, or NULL for the default context
* \see \ref mtasync
*/
-API_EXPORTED void libusb_lock_events(libusb_context *ctx)
+void API_EXPORTED libusb_lock_events(libusb_context *ctx)
{
USBI_GET_CONTEXT(ctx);
- pthread_mutex_lock(&ctx->events_lock);
+ usbi_mutex_lock(&ctx->events_lock);
ctx->event_handler_active = 1;
}
* \param ctx the context to operate on, or NULL for the default context
* \see \ref mtasync
*/
-API_EXPORTED void libusb_unlock_events(libusb_context *ctx)
+void API_EXPORTED libusb_unlock_events(libusb_context *ctx)
{
USBI_GET_CONTEXT(ctx);
ctx->event_handler_active = 0;
- pthread_mutex_unlock(&ctx->events_lock);
+ usbi_mutex_unlock(&ctx->events_lock);
/* FIXME: perhaps we should be a bit more efficient by not broadcasting
* the availability of the events lock when we are modifying pollfds
* (check ctx->pollfd_modify)? */
- pthread_mutex_lock(&ctx->event_waiters_lock);
- pthread_cond_broadcast(&ctx->event_waiters_cond);
- pthread_mutex_unlock(&ctx->event_waiters_lock);
+ usbi_mutex_lock(&ctx->event_waiters_lock);
+ usbi_cond_broadcast(&ctx->event_waiters_cond);
+ usbi_mutex_unlock(&ctx->event_waiters_lock);
}
/** \ingroup poll
* Determine if it is still OK for this thread to be doing event handling.
*
- * Sometimes, libusb needs to temporarily pause all event handlers, and this
+ * Sometimes, libusbx needs to temporarily pause all event handlers, and this
* is the function you should use before polling file descriptors to see if
* this is the case.
*
* \returns 0 if this thread must give up the events lock
* \see \ref fullstory "Multi-threaded I/O: the full story"
*/
-API_EXPORTED int libusb_event_handling_ok(libusb_context *ctx)
+int API_EXPORTED libusb_event_handling_ok(libusb_context *ctx)
{
int r;
USBI_GET_CONTEXT(ctx);
/* is someone else waiting to modify poll fds? if so, don't let this thread
* continue event handling */
- pthread_mutex_lock(&ctx->pollfd_modify_lock);
+ usbi_mutex_lock(&ctx->pollfd_modify_lock);
r = ctx->pollfd_modify;
- pthread_mutex_unlock(&ctx->pollfd_modify_lock);
+ usbi_mutex_unlock(&ctx->pollfd_modify_lock);
if (r) {
usbi_dbg("someone else is modifying poll fds");
return 0;
* \returns 0 if there are no threads currently handling events
* \see \ref mtasync
*/
-API_EXPORTED int libusb_event_handler_active(libusb_context *ctx)
+int API_EXPORTED libusb_event_handler_active(libusb_context *ctx)
{
int r;
USBI_GET_CONTEXT(ctx);
/* is someone else waiting to modify poll fds? if so, don't let this thread
* start event handling -- indicate that event handling is happening */
- pthread_mutex_lock(&ctx->pollfd_modify_lock);
+ usbi_mutex_lock(&ctx->pollfd_modify_lock);
r = ctx->pollfd_modify;
- pthread_mutex_unlock(&ctx->pollfd_modify_lock);
+ usbi_mutex_unlock(&ctx->pollfd_modify_lock);
if (r) {
usbi_dbg("someone else is modifying poll fds");
return 1;
* events, then call libusb_wait_for_event().
*
* You only need to use this lock if you are developing an application
- * which calls poll() or select() on libusb's file descriptors directly,
+ * which calls poll() or select() on libusbx's file descriptors directly,
* <b>and</b> may potentially be handling events from 2 threads simultaenously.
- * If you stick to libusb's event handling loop functions (e.g.
+ * If you stick to libusbx's event handling loop functions (e.g.
* libusb_handle_events()) then you do not need to be concerned with this
* locking.
*
* \param ctx the context to operate on, or NULL for the default context
* \see \ref mtasync
*/
-API_EXPORTED void libusb_lock_event_waiters(libusb_context *ctx)
+void API_EXPORTED libusb_lock_event_waiters(libusb_context *ctx)
{
USBI_GET_CONTEXT(ctx);
- pthread_mutex_lock(&ctx->event_waiters_lock);
+ usbi_mutex_lock(&ctx->event_waiters_lock);
}
/** \ingroup poll
* \param ctx the context to operate on, or NULL for the default context
* \see \ref mtasync
*/
-API_EXPORTED void libusb_unlock_event_waiters(libusb_context *ctx)
+void API_EXPORTED libusb_unlock_event_waiters(libusb_context *ctx)
{
USBI_GET_CONTEXT(ctx);
- pthread_mutex_unlock(&ctx->event_waiters_lock);
+ usbi_mutex_unlock(&ctx->event_waiters_lock);
}
/** \ingroup poll
* \returns 1 if the timeout expired
* \see \ref mtasync
*/
-API_EXPORTED int libusb_wait_for_event(libusb_context *ctx, struct timeval *tv)
+int API_EXPORTED libusb_wait_for_event(libusb_context *ctx, struct timeval *tv)
{
struct timespec timeout;
int r;
USBI_GET_CONTEXT(ctx);
if (tv == NULL) {
- pthread_cond_wait(&ctx->event_waiters_cond, &ctx->event_waiters_lock);
+ usbi_cond_wait(&ctx->event_waiters_cond, &ctx->event_waiters_lock);
return 0;
}
- r = clock_gettime(CLOCK_REALTIME, &timeout);
+ r = usbi_backend->clock_gettime(USBI_CLOCK_REALTIME, &timeout);
if (r < 0) {
usbi_err(ctx, "failed to read realtime clock, error %d", errno);
return LIBUSB_ERROR_OTHER;
timeout.tv_sec++;
}
- r = pthread_cond_timedwait(&ctx->event_waiters_cond,
+ r = usbi_cond_timedwait(&ctx->event_waiters_cond,
&ctx->event_waiters_lock, &timeout);
return (r == ETIMEDOUT);
}
static void handle_timeout(struct usbi_transfer *itransfer)
{
struct libusb_transfer *transfer =
- __USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
+ USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
int r;
itransfer->flags |= USBI_TRANSFER_TIMED_OUT;
"async cancel failed %d errno=%d", r, errno);
}
-static int handle_timeouts(struct libusb_context *ctx)
+static int handle_timeouts_locked(struct libusb_context *ctx)
{
+ int r;
struct timespec systime_ts;
struct timeval systime;
struct usbi_transfer *transfer;
- int r = 0;
- USBI_GET_CONTEXT(ctx);
- pthread_mutex_lock(&ctx->flying_transfers_lock);
if (list_empty(&ctx->flying_transfers))
- goto out;
+ return 0;
/* get current time */
- r = clock_gettime(CLOCK_MONOTONIC, &systime_ts);
+ r = usbi_backend->clock_gettime(USBI_CLOCK_MONOTONIC, &systime_ts);
if (r < 0)
- goto out;
+ return r;
TIMESPEC_TO_TIMEVAL(&systime, &systime_ts);
/* iterate through flying transfers list, finding all transfers that
* have expired timeouts */
- list_for_each_entry(transfer, &ctx->flying_transfers, list) {
+ list_for_each_entry(transfer, &ctx->flying_transfers, list, struct usbi_transfer) {
struct timeval *cur_tv = &transfer->timeout;
/* if we've reached transfers of infinite timeout, we're all done */
if (!timerisset(cur_tv))
- goto out;
+ return 0;
/* ignore timeouts we've already handled */
- if (transfer->flags & USBI_TRANSFER_TIMED_OUT)
+ if (transfer->flags & (USBI_TRANSFER_TIMED_OUT | USBI_TRANSFER_OS_HANDLES_TIMEOUT))
continue;
/* if transfer has non-expired timeout, nothing more to do */
if ((cur_tv->tv_sec > systime.tv_sec) ||
(cur_tv->tv_sec == systime.tv_sec &&
cur_tv->tv_usec > systime.tv_usec))
- goto out;
-
+ return 0;
+
/* otherwise, we've got an expired timeout to handle */
handle_timeout(transfer);
}
+ return 0;
+}
+
+static int handle_timeouts(struct libusb_context *ctx)
+{
+ int r;
+ USBI_GET_CONTEXT(ctx);
+ usbi_mutex_lock(&ctx->flying_transfers_lock);
+ r = handle_timeouts_locked(ctx);
+ usbi_mutex_unlock(&ctx->flying_transfers_lock);
+ return r;
+}
+
+#ifdef USBI_TIMERFD_AVAILABLE
+static int handle_timerfd_trigger(struct libusb_context *ctx)
+{
+ int r;
+
+ usbi_mutex_lock(&ctx->flying_transfers_lock);
+
+ /* process the timeout that just happened */
+ r = handle_timeouts_locked(ctx);
+ if (r < 0)
+ goto out;
+
+ /* arm for next timeout*/
+ r = arm_timerfd_for_next_timeout(ctx);
out:
- pthread_mutex_unlock(&ctx->flying_transfers_lock);
+ usbi_mutex_unlock(&ctx->flying_transfers_lock);
return r;
}
+#endif
/* do the actual event handling. assumes that no other thread is concurrently
* doing the same thing. */
{
int r;
struct usbi_pollfd *ipollfd;
- nfds_t nfds = 0;
- struct pollfd *fds;
+ POLL_NFDS_TYPE nfds = 0;
+ struct pollfd *fds = NULL;
int i = -1;
int timeout_ms;
- pthread_mutex_lock(&ctx->pollfds_lock);
- list_for_each_entry(ipollfd, &ctx->pollfds, list)
+ usbi_mutex_lock(&ctx->pollfds_lock);
+ list_for_each_entry(ipollfd, &ctx->pollfds, list, struct usbi_pollfd)
nfds++;
/* TODO: malloc when number of fd's changes, not on every poll */
- fds = malloc(sizeof(*fds) * nfds);
- if (!fds)
+ if (nfds != 0)
+ fds = malloc(sizeof(*fds) * nfds);
+ if (!fds) {
+ usbi_mutex_unlock(&ctx->pollfds_lock);
return LIBUSB_ERROR_NO_MEM;
+ }
- list_for_each_entry(ipollfd, &ctx->pollfds, list) {
+ list_for_each_entry(ipollfd, &ctx->pollfds, list, struct usbi_pollfd) {
struct libusb_pollfd *pollfd = &ipollfd->pollfd;
int fd = pollfd->fd;
i++;
fds[i].events = pollfd->events;
fds[i].revents = 0;
}
- pthread_mutex_unlock(&ctx->pollfds_lock);
+ usbi_mutex_unlock(&ctx->pollfds_lock);
timeout_ms = (tv->tv_sec * 1000) + (tv->tv_usec / 1000);
timeout_ms++;
usbi_dbg("poll() %d fds with timeout in %dms", nfds, timeout_ms);
- r = poll(fds, nfds, timeout_ms);
+ r = usbi_poll(fds, nfds, timeout_ms);
usbi_dbg("poll() returned %d", r);
if (r == 0) {
free(fds);
}
}
+#ifdef USBI_TIMERFD_AVAILABLE
+ /* on timerfd configurations, fds[1] is the timerfd */
+ if (usbi_using_timerfd(ctx) && fds[1].revents) {
+ /* timerfd indicates that a timeout has expired */
+ int ret;
+ usbi_dbg("timerfd triggered");
+
+ ret = handle_timerfd_trigger(ctx);
+ if (ret < 0) {
+ /* return error code */
+ r = ret;
+ goto handled;
+ } else if (r == 1) {
+ /* no more active file descriptors, nothing more to do */
+ r = 0;
+ goto handled;
+ } else {
+ /* more events pending...
+ * prevent OS backend from trying to handle events on timerfd */
+ fds[1].revents = 0;
+ r--;
+ }
+ }
+#endif
+
r = usbi_backend->handle_events(ctx, fds, nfds, r);
if (r)
usbi_err(ctx, "backend handle_events failed with error %d", r);
/** \ingroup poll
* Handle any pending events.
*
- * libusb determines "pending events" by checking if any timeouts have expired
+ * libusbx determines "pending events" by checking if any timeouts have expired
* and by checking the set of file descriptors for activity.
*
* If a zero timeval is passed, this function will handle any already-pending
* timeout. If an event arrives or a signal is raised, this function will
* return early.
*
+ * If the parameter completed is not NULL then <em>after obtaining the event
+ * handling lock</em> this function will return immediately if the integer
+ * pointed to is not 0. This allows for race free waiting for the completion
+ * of a specific transfer.
+ *
* \param ctx the context to operate on, or NULL for the default context
- * \param tv the maximum time to block waiting for events, or zero for
- * non-blocking mode
+ * \param tv the maximum time to block waiting for events, or an all zero
+ * timeval struct for non-blocking mode
+ * \param completed pointer to completion integer to check, or NULL
* \returns 0 on success, or a LIBUSB_ERROR code on failure
+ * \see \ref mtasync
*/
-API_EXPORTED int libusb_handle_events_timeout(libusb_context *ctx,
- struct timeval *tv)
+int API_EXPORTED libusb_handle_events_timeout_completed(libusb_context *ctx,
+ struct timeval *tv, int *completed)
{
int r;
struct timeval poll_timeout;
retry:
if (libusb_try_lock_events(ctx) == 0) {
- /* we obtained the event lock: do our own event handling */
- r = handle_events(ctx, &poll_timeout);
+ if (completed == NULL || !*completed) {
+ /* we obtained the event lock: do our own event handling */
+ usbi_dbg("doing our own event handling");
+ r = handle_events(ctx, &poll_timeout);
+ }
libusb_unlock_events(ctx);
return r;
}
- /* another thread is doing event handling. wait for pthread events that
+ /* another thread is doing event handling. wait for thread events that
* notify event completion. */
libusb_lock_event_waiters(ctx);
+ if (completed && *completed)
+ goto already_done;
+
if (!libusb_event_handler_active(ctx)) {
/* we hit a race: whoever was event handling earlier finished in the
* time it took us to reach this point. try the cycle again. */
usbi_dbg("another thread is doing event handling");
r = libusb_wait_for_event(ctx, &poll_timeout);
+
+already_done:
libusb_unlock_event_waiters(ctx);
if (r < 0)
}
/** \ingroup poll
- * Handle any pending events in blocking mode with a sensible timeout. This
- * timeout is currently hardcoded at 2 seconds but we may change this if we
- * decide other values are more sensible. For finer control over whether this
- * function is blocking or non-blocking, or the maximum timeout, use
- * libusb_handle_events_timeout() instead.
+ * Handle any pending events
+ *
+ * Like libusb_handle_events_timeout_completed(), but without the completed
+ * parameter, calling this function is equivalent to calling
+ * libusb_handle_events_timeout_completed() with a NULL completed parameter.
+ *
+ * This function is kept primarily for backwards compatibility.
+ * All new code should call libusb_handle_events_completed() or
+ * libusb_handle_events_timeout_completed() to avoid race conditions.
+ *
+ * \param ctx the context to operate on, or NULL for the default context
+ * \param tv the maximum time to block waiting for events, or an all zero
+ * timeval struct for non-blocking mode
+ * \returns 0 on success, or a LIBUSB_ERROR code on failure
+ */
+int API_EXPORTED libusb_handle_events_timeout(libusb_context *ctx,
+ struct timeval *tv)
+{
+ return libusb_handle_events_timeout_completed(ctx, tv, NULL);
+}
+
+/** \ingroup poll
+ * Handle any pending events in blocking mode. There is currently a timeout
+ * hardcoded at 60 seconds but we plan to make it unlimited in future. For
+ * finer control over whether this function is blocking or non-blocking, or
+ * for control over the timeout, use libusb_handle_events_timeout_completed()
+ * instead.
+ *
+ * This function is kept primarily for backwards compatibility.
+ * All new code should call libusb_handle_events_completed() or
+ * libusb_handle_events_timeout_completed() to avoid race conditions.
+ *
+ * \param ctx the context to operate on, or NULL for the default context
+ * \returns 0 on success, or a LIBUSB_ERROR code on failure
+ */
+int API_EXPORTED libusb_handle_events(libusb_context *ctx)
+{
+ struct timeval tv;
+ tv.tv_sec = 60;
+ tv.tv_usec = 0;
+ return libusb_handle_events_timeout_completed(ctx, &tv, NULL);
+}
+
+/** \ingroup poll
+ * Handle any pending events in blocking mode.
+ *
+ * Like libusb_handle_events(), with the addition of a completed parameter
+ * to allow for race free waiting for the completion of a specific transfer.
+ *
+ * See libusb_handle_events_timeout_completed() for details on the completed
+ * parameter.
*
* \param ctx the context to operate on, or NULL for the default context
+ * \param completed pointer to completion integer to check, or NULL
* \returns 0 on success, or a LIBUSB_ERROR code on failure
+ * \see \ref mtasync
*/
-API_EXPORTED int libusb_handle_events(libusb_context *ctx)
+int API_EXPORTED libusb_handle_events_completed(libusb_context *ctx,
+ int *completed)
{
struct timeval tv;
- tv.tv_sec = 2;
+ tv.tv_sec = 60;
tv.tv_usec = 0;
- return libusb_handle_events_timeout(ctx, &tv);
+ return libusb_handle_events_timeout_completed(ctx, &tv, completed);
}
/** \ingroup poll
* held, see libusb_lock_events().
*
* This function is designed to be called under the situation where you have
- * taken the event lock and are calling poll()/select() directly on libusb's
+ * taken the event lock and are calling poll()/select() directly on libusbx's
* file descriptors (as opposed to using libusb_handle_events() or similar).
- * You detect events on libusb's descriptors, so you then call this function
+ * You detect events on libusbx's descriptors, so you then call this function
* with a zero timeout value (while still holding the event lock).
*
* \param ctx the context to operate on, or NULL for the default context
* \returns 0 on success, or a LIBUSB_ERROR code on failure
* \see \ref mtasync
*/
-API_EXPORTED int libusb_handle_events_locked(libusb_context *ctx,
+int API_EXPORTED libusb_handle_events_locked(libusb_context *ctx,
struct timeval *tv)
{
int r;
}
/** \ingroup poll
- * Determine the next internal timeout that libusb needs to handle. You only
+ * Determines whether your application must apply special timing considerations
+ * when monitoring libusbx's file descriptors.
+ *
+ * This function is only useful for applications which retrieve and poll
+ * libusbx's file descriptors in their own main loop (\ref pollmain).
+ *
+ * Ordinarily, libusbx's event handler needs to be called into at specific
+ * moments in time (in addition to times when there is activity on the file
+ * descriptor set). The usual approach is to use libusb_get_next_timeout()
+ * to learn about when the next timeout occurs, and to adjust your
+ * poll()/select() timeout accordingly so that you can make a call into the
+ * library at that time.
+ *
+ * Some platforms supported by libusbx do not come with this baggage - any
+ * events relevant to timing will be represented by activity on the file
+ * descriptor set, and libusb_get_next_timeout() will always return 0.
+ * This function allows you to detect whether you are running on such a
+ * platform.
+ *
+ * Since v1.0.5.
+ *
+ * \param ctx the context to operate on, or NULL for the default context
+ * \returns 0 if you must call into libusbx at times determined by
+ * libusb_get_next_timeout(), or 1 if all timeout events are handled internally
+ * or through regular activity on the file descriptors.
+ * \see \ref pollmain "Polling libusbx file descriptors for event handling"
+ */
+int API_EXPORTED libusb_pollfds_handle_timeouts(libusb_context *ctx)
+{
+#if defined(USBI_TIMERFD_AVAILABLE)
+ USBI_GET_CONTEXT(ctx);
+ return usbi_using_timerfd(ctx);
+#else
+ (void)ctx;
+ return 0;
+#endif
+}
+
+/** \ingroup poll
+ * Determine the next internal timeout that libusbx needs to handle. You only
* need to use this function if you are calling poll() or select() or similar
- * on libusb's file descriptors yourself - you do not need to use it if you
+ * on libusbx's file descriptors yourself - you do not need to use it if you
* are calling libusb_handle_events() or a variant directly.
- *
+ *
* You should call this function in your main loop in order to determine how
- * long to wait for select() or poll() to return results. libusb needs to be
+ * long to wait for select() or poll() to return results. libusbx needs to be
* called into at this timeout, so you should use it as an upper bound on
* your select() or poll() call.
*
* When the timeout has expired, call into libusb_handle_events_timeout()
- * (perhaps in non-blocking mode) so that libusb can handle the timeout.
+ * (perhaps in non-blocking mode) so that libusbx can handle the timeout.
*
* This function may return 1 (success) and an all-zero timeval. If this is
- * the case, it indicates that libusb has a timeout that has already expired
+ * the case, it indicates that libusbx has a timeout that has already expired
* so you should call libusb_handle_events_timeout() or similar immediately.
* A return code of 0 indicates that there are no pending timeouts.
*
+ * On some platforms, this function will always returns 0 (no pending
+ * timeouts). See \ref polltime.
+ *
* \param ctx the context to operate on, or NULL for the default context
* \param tv output location for a relative time against the current
- * clock in which libusb must be called into in order to process timeout events
+ * clock in which libusbx must be called into in order to process timeout events
* \returns 0 if there are no pending timeouts, 1 if a timeout was returned,
* or LIBUSB_ERROR_OTHER on failure
*/
-API_EXPORTED int libusb_get_next_timeout(libusb_context *ctx,
+int API_EXPORTED libusb_get_next_timeout(libusb_context *ctx,
struct timeval *tv)
{
struct usbi_transfer *transfer;
int found = 0;
USBI_GET_CONTEXT(ctx);
- pthread_mutex_lock(&ctx->flying_transfers_lock);
+ if (usbi_using_timerfd(ctx))
+ return 0;
+
+ usbi_mutex_lock(&ctx->flying_transfers_lock);
if (list_empty(&ctx->flying_transfers)) {
- pthread_mutex_unlock(&ctx->flying_transfers_lock);
+ usbi_mutex_unlock(&ctx->flying_transfers_lock);
usbi_dbg("no URBs, no timeout!");
return 0;
}
/* find next transfer which hasn't already been processed as timed out */
- list_for_each_entry(transfer, &ctx->flying_transfers, list) {
- if (!(transfer->flags & USBI_TRANSFER_TIMED_OUT)) {
- found = 1;
- break;
- }
+ list_for_each_entry(transfer, &ctx->flying_transfers, list, struct usbi_transfer) {
+ if (transfer->flags & (USBI_TRANSFER_TIMED_OUT | USBI_TRANSFER_OS_HANDLES_TIMEOUT))
+ continue;
+
+ /* no timeout for this transfer? */
+ if (!timerisset(&transfer->timeout))
+ continue;
+
+ found = 1;
+ break;
}
- pthread_mutex_unlock(&ctx->flying_transfers_lock);
+ usbi_mutex_unlock(&ctx->flying_transfers_lock);
if (!found) {
- usbi_dbg("all URBs have already been processed for timeouts");
+ usbi_dbg("no URB with timeout or all handled by OS; no timeout!");
return 0;
}
next_timeout = &transfer->timeout;
- /* no timeout for next transfer */
- if (!timerisset(next_timeout)) {
- usbi_dbg("no URBs with timeouts, no timeout!");
- return 0;
- }
-
- r = clock_gettime(CLOCK_MONOTONIC, &cur_ts);
+ r = usbi_backend->clock_gettime(USBI_CLOCK_MONOTONIC, &cur_ts);
if (r < 0) {
usbi_err(ctx, "failed to read monotonic clock, errno=%d", errno);
- return LIBUSB_ERROR_OTHER;
+ return 0;
}
TIMESPEC_TO_TIMEVAL(&cur_tv, &cur_ts);
- if (timercmp(&cur_tv, next_timeout, >=)) {
+ if (!timercmp(&cur_tv, next_timeout, <)) {
usbi_dbg("first timeout already expired");
timerclear(tv);
} else {
/** \ingroup poll
* Register notification functions for file descriptor additions/removals.
* These functions will be invoked for every new or removed file descriptor
- * that libusb uses as an event source.
+ * that libusbx uses as an event source.
*
* To remove notifiers, pass NULL values for the function pointers.
*
* \param user_data User data to be passed back to callbacks (useful for
* passing context information)
*/
-API_EXPORTED void libusb_set_pollfd_notifiers(libusb_context *ctx,
+void API_EXPORTED libusb_set_pollfd_notifiers(libusb_context *ctx,
libusb_pollfd_added_cb added_cb, libusb_pollfd_removed_cb removed_cb,
void *user_data)
{
usbi_dbg("add fd %d events %d", fd, events);
ipollfd->pollfd.fd = fd;
ipollfd->pollfd.events = events;
- pthread_mutex_lock(&ctx->pollfds_lock);
+ usbi_mutex_lock(&ctx->pollfds_lock);
list_add_tail(&ipollfd->list, &ctx->pollfds);
- pthread_mutex_unlock(&ctx->pollfds_lock);
+ usbi_mutex_unlock(&ctx->pollfds_lock);
if (ctx->fd_added_cb)
ctx->fd_added_cb(fd, events, ctx->fd_cb_user_data);
int found = 0;
usbi_dbg("remove fd %d", fd);
- pthread_mutex_lock(&ctx->pollfds_lock);
- list_for_each_entry(ipollfd, &ctx->pollfds, list)
+ usbi_mutex_lock(&ctx->pollfds_lock);
+ list_for_each_entry(ipollfd, &ctx->pollfds, list, struct usbi_pollfd)
if (ipollfd->pollfd.fd == fd) {
found = 1;
break;
if (!found) {
usbi_dbg("couldn't find fd %d to remove", fd);
- pthread_mutex_unlock(&ctx->pollfds_lock);
+ usbi_mutex_unlock(&ctx->pollfds_lock);
return;
}
list_del(&ipollfd->list);
- pthread_mutex_unlock(&ctx->pollfds_lock);
+ usbi_mutex_unlock(&ctx->pollfds_lock);
free(ipollfd);
if (ctx->fd_removed_cb)
ctx->fd_removed_cb(fd, ctx->fd_cb_user_data);
/** \ingroup poll
* Retrieve a list of file descriptors that should be polled by your main loop
- * as libusb event sources.
+ * as libusbx event sources.
*
* The returned list is NULL-terminated and should be freed with free() when
* done. The actual list contents must not be touched.
*
+ * As file descriptors are a Unix-specific concept, this function is not
+ * available on Windows and will always return NULL.
+ *
* \param ctx the context to operate on, or NULL for the default context
- * \returns a NULL-terminated list of libusb_pollfd structures, or NULL on
- * error
+ * \returns a NULL-terminated list of libusb_pollfd structures
+ * \returns NULL on error
+ * \returns NULL on platforms where the functionality is not available
*/
-API_EXPORTED const struct libusb_pollfd **libusb_get_pollfds(
+DEFAULT_VISIBILITY
+const struct libusb_pollfd ** LIBUSB_CALL libusb_get_pollfds(
libusb_context *ctx)
{
+#ifndef OS_WINDOWS
struct libusb_pollfd **ret = NULL;
struct usbi_pollfd *ipollfd;
size_t i = 0;
size_t cnt = 0;
USBI_GET_CONTEXT(ctx);
- pthread_mutex_lock(&ctx->pollfds_lock);
- list_for_each_entry(ipollfd, &ctx->pollfds, list)
+ usbi_mutex_lock(&ctx->pollfds_lock);
+ list_for_each_entry(ipollfd, &ctx->pollfds, list, struct usbi_pollfd)
cnt++;
ret = calloc(cnt + 1, sizeof(struct libusb_pollfd *));
if (!ret)
goto out;
- list_for_each_entry(ipollfd, &ctx->pollfds, list)
+ list_for_each_entry(ipollfd, &ctx->pollfds, list, struct usbi_pollfd)
ret[i++] = (struct libusb_pollfd *) ipollfd;
ret[cnt] = NULL;
out:
- pthread_mutex_unlock(&ctx->pollfds_lock);
+ usbi_mutex_unlock(&ctx->pollfds_lock);
return (const struct libusb_pollfd **) ret;
+#else
+ usbi_err(ctx, "external polling of libusbx's internal descriptors "\
+ "is not yet supported on Windows platforms");
+ return NULL;
+#endif
}
/* Backends call this from handle_events to report disconnection of a device.
/* terminate all pending transfers with the LIBUSB_TRANSFER_NO_DEVICE
* status code.
- *
+ *
* this is a bit tricky because:
* 1. we can't do transfer completion while holding flying_transfers_lock
* 2. the transfers list can change underneath us - if we were to build a
*/
while (1) {
- pthread_mutex_lock(&HANDLE_CTX(handle)->flying_transfers_lock);
+ usbi_mutex_lock(&HANDLE_CTX(handle)->flying_transfers_lock);
to_cancel = NULL;
- list_for_each_entry(cur, &HANDLE_CTX(handle)->flying_transfers, list)
- if (__USBI_TRANSFER_TO_LIBUSB_TRANSFER(cur)->dev_handle == handle) {
+ list_for_each_entry(cur, &HANDLE_CTX(handle)->flying_transfers, list, struct usbi_transfer)
+ if (USBI_TRANSFER_TO_LIBUSB_TRANSFER(cur)->dev_handle == handle) {
to_cancel = cur;
break;
}
- pthread_mutex_unlock(&HANDLE_CTX(handle)->flying_transfers_lock);
+ usbi_mutex_unlock(&HANDLE_CTX(handle)->flying_transfers_lock);
if (!to_cancel)
break;
}
}
-
projects / platform / upstream / libusb.git / blobdiff