+/* -*- Mode: C; indent-tabs-mode:t ; c-basic-offset:8 -*- */
/*
* I/O functions for libusb
- * Copyright (C) 2007-2009 Daniel Drake <dsd@gentoo.org>
- * Copyright (c) 2001 Johannes Erdfelt <johannes@erdfelt.com>
+ * 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 <assert.h>
#include <errno.h>
-#include <signal.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
-
+#ifdef HAVE_SIGNAL_H
+#include <signal.h>
+#endif
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
-
#ifdef USBI_TIMERFD_AVAILABLE
#include <sys/timerfd.h>
#endif
#include "libusbi.h"
+#include "hotplug.h"
/**
* \page io Synchronous and asynchronous device I/O
*
- * \section intro Introduction
+ * \section io_intro Introduction
*
* If you're using libusb in your application, you're probably wanting to
* perform I/O with devices - you want to perform USB data transfers.
* 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
* libusb_get_iso_packet_buffer() and libusb_get_iso_packet_buffer_simple()
* functions may help you here.
*
+ * <b>Note</b>: Some operating systems (e.g. Linux) may impose limits on the
+ * length of individual isochronous packets and/or the total length of the
+ * isochronous transfer. Such limits can be difficult for libusb to detect,
+ * so the library will simply try and submit the transfer as set up by you.
+ * If the transfer fails to submit because it is too large,
+ * libusb_submit_transfer() will return
+ * \ref libusb_error::LIBUSB_ERROR_INVALID_PARAM "LIBUSB_ERROR_INVALID_PARAM".
+ *
* \section asyncmem Memory caveats
*
* In most circumstances, it is not safe to use stack memory for transfer
*
* \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
+ * An asynchronous model requires that libusb perform work at various
* points in time - namely processing the results of previously-submitted
* transfers and invoking the user-supplied callback function.
*
* application must call into when libusb has work do to. This gives libusb
* 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
- * 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
+ * There are 2 different approaches to dealing with libusb_handle_events:
+ *
* -# Repeatedly call libusb_handle_events() in blocking mode from a dedicated
* thread.
+ * -# Integrate libusb with your application's main event loop. libusb
+ * exposes a set of file descriptors which allow you to do this.
*
- * 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 first approach has the big advantage that it will also work on Windows
+ * were libusb' poll API for select / poll integration is not available. So
+ * if you want to support Windows and use the async API, you must use this
+ * approach, see the \ref eventthread "Using an event handling thread" section
+ * below for details.
*
- * 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
- * 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
- * is detected on such descriptors you know it is time to call
- * libusb_handle_events().
+ * If you prefer a single threaded approach with a single central event loop,
+ * see the \ref poll "polling and timing" section for how to integrate libusb
+ * into your application's main event loop.
*
- * There is one final event handling complication. libusb 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
- * sometimes needs to be called into at fixed points in time even when there
- * is no file descriptor activity.
+ * \section eventthread Using an event handling thread
+ *
+ * Lets begin with stating the obvious: If you're going to use a separate
+ * thread for libusb event handling, your callback functions MUST be
+ * threadsafe.
+ *
+ * Other then that doing event handling from a separate thread, is mostly
+ * simple. You can use an event thread function as follows:
+\code
+void *event_thread_func(void *ctx)
+{
+ while (event_thread_run)
+ libusb_handle_events(ctx);
+
+ return NULL;
+}
+\endcode
*
- * For the details on retrieving the set of file descriptors and determining
- * the next timeout, see the \ref poll "polling and timing" API documentation.
+ * There is one caveat though, stopping this thread requires setting the
+ * event_thread_run variable to 0, and after that libusb_handle_events() needs
+ * to return control to event_thread_func. But unless some event happens,
+ * libusb_handle_events() will not return.
+ *
+ * There are 2 different ways of dealing with this, depending on if your
+ * application uses libusb' \ref hotplug "hotplug" support or not.
+ *
+ * Applications which do not use hotplug support, should not start the event
+ * thread until after their first call to libusb_open(), and should stop the
+ * thread when closing the last open device as follows:
+\code
+void my_close_handle(libusb_device_handle *handle)
+{
+ if (open_devs == 1)
+ event_thread_run = 0;
+
+ libusb_close(handle); // This wakes up libusb_handle_events()
+
+ if (open_devs == 1)
+ pthread_join(event_thread);
+
+ open_devs--;
+}
+\endcode
+ *
+ * Applications using hotplug support should start the thread at program init,
+ * after having successfully called libusb_hotplug_register_callback(), and
+ * should stop the thread at program exit as follows:
+\code
+void my_libusb_exit(void)
+{
+ event_thread_run = 0;
+ libusb_hotplug_deregister_callback(ctx, hotplug_cb_handle); // This wakes up libusb_handle_events()
+ pthread_join(event_thread);
+ libusb_exit(ctx);
+}
+\endcode
*/
/**
* asynchronous API documentation. In summary, libusb 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.
+ *
+ * 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
+ * is detected on such descriptors you know it is time to call
+ * libusb_handle_events().
+ *
+ * There is one final event handling complication. libusb supports
+ * asynchronous transfers which time out after a specified time period.
+ *
+ * On some platforms a timerfd is used, so the timeout handling is just another
+ * fd, on other platforms this requires that libusb is called into at or after
+ * the timeout to handle it. So, in addition to considering libusb's file
+ * descriptors in your main event loop, you must also consider that libusb
+ * sometimes needs to be called into at fixed points in time even when there
+ * is no file descriptor activity, see \ref polltime details.
+ *
* In order to know precisely when libusb needs to be called into, libusb
* offers you a set of pollable file descriptors and information about when
* the next timeout expires.
*
* \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. Applications which
+ * want to support Windows are advised to use an \ref eventthread
+ * "event handling thread" instead.
+ *
* 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
poll(on libusb file descriptors plus any other event sources of interest,
using a timeout no larger than the value libusb just suggested)
if (poll() indicated activity on libusb file descriptors)
- libusb_handle_events_timeout(ctx, 0);
+ libusb_handle_events_timeout(ctx, &zero_tv);
if (time has elapsed to or beyond the libusb timeout)
- libusb_handle_events_timeout(ctx, 0);
+ libusb_handle_events_timeout(ctx, &zero_tv);
// handle events from other sources here
}
poll(on libusb file descriptors plus any other event sources of interest,
using any timeout that you like)
if (poll() indicated activity on libusb file descriptors)
- libusb_handle_events_timeout(ctx, 0);
+ libusb_handle_events_timeout(ctx, &zero_tv);
// handle events from other sources here
}
void myfunc() {
struct libusb_transfer *transfer;
- unsigned char buffer[LIBUSB_CONTROL_SETUP_SIZE];
+ unsigned char buffer[LIBUSB_CONTROL_SETUP_SIZE] __attribute__ ((aligned (2)));
int completed = 0;
transfer = libusb_alloc_transfer(0);
while (!completed) {
poll(libusb 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
*
* 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 - libusb 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:
+ *
+\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 libusb exposes file
* descriptors to allow for you to integrate asynchronous USB I/O into
* libusb's back. If you do take libusb'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.
while (!completed) {
poll(libusb 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
goto retry;
}
- libusb_wait_for_event(ctx);
+ libusb_wait_for_event(ctx, NULL);
}
libusb_unlock_event_waiters(ctx);
}
*
* -# During initialization, libusb 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.
+ * -# During libusb_close(), libusb writes some dummy data on this event pipe.
* This immediately interrupts the event handler. libusb also records
* internally that it is trying to interrupt event handlers for this
* high-priority event.
* 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
+ * -# libusb sends some dummy data on the event 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
int r;
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(&ctx->events_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);
+ usbi_mutex_init(&ctx->event_data_lock, NULL);
list_init(&ctx->flying_transfers);
- list_init(&ctx->pollfds);
+ list_init(&ctx->ipollfds);
+ list_init(&ctx->hotplug_msgs);
+ list_init(&ctx->completed_transfers);
/* FIXME should use an eventfd on kernels that support it */
- r = usbi_pipe(ctx->ctrl_pipe);
+ r = usbi_pipe(ctx->event_pipe);
if (r < 0) {
r = LIBUSB_ERROR_OTHER;
goto err;
}
- r = usbi_add_pollfd(ctx, ctx->ctrl_pipe[0], POLLIN);
+ r = usbi_add_pollfd(ctx, ctx->event_pipe[0], POLLIN);
if (r < 0)
goto err_close_pipe;
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;
- }
+ if (r < 0)
+ goto err_close_timerfd;
} else {
usbi_dbg("timerfd not available (code %d error %d)", ctx->timerfd, errno);
ctx->timerfd = -1;
return 0;
+#ifdef USBI_TIMERFD_AVAILABLE
+err_close_timerfd:
+ close(ctx->timerfd);
+ usbi_remove_pollfd(ctx, ctx->event_pipe[0]);
+#endif
err_close_pipe:
- usbi_close(ctx->ctrl_pipe[0]);
- usbi_close(ctx->ctrl_pipe[1]);
+ usbi_close(ctx->event_pipe[0]);
+ usbi_close(ctx->event_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);
+ usbi_mutex_destroy(&ctx->event_data_lock);
return r;
}
void usbi_io_exit(struct libusb_context *ctx)
{
- usbi_remove_pollfd(ctx, ctx->ctrl_pipe[0]);
- usbi_close(ctx->ctrl_pipe[0]);
- usbi_close(ctx->ctrl_pipe[1]);
+ usbi_remove_pollfd(ctx, ctx->event_pipe[0]);
+ usbi_close(ctx->event_pipe[0]);
+ usbi_close(ctx->event_pipe[1]);
#ifdef USBI_TIMERFD_AVAILABLE
if (usbi_using_timerfd(ctx)) {
usbi_remove_pollfd(ctx, 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);
+ usbi_mutex_destroy(&ctx->event_data_lock);
+ if (ctx->pollfds)
+ free(ctx->pollfds);
}
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;
current_time.tv_sec += timeout / 1000;
current_time.tv_nsec += (timeout % 1000) * 1000000;
- if (current_time.tv_nsec > 1000000000) {
+ while (current_time.tv_nsec >= 1000000000) {
current_time.tv_nsec -= 1000000000;
current_time.tv_sec++;
}
return 0;
}
-/* 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);
- 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)) {
- list_add(&transfer->list, &ctx->flying_transfers);
- if (timerisset(timeout))
- r = 1;
- goto out;
- }
-
- /* if we have infinite timeout, append to end of list */
- if (!timerisset(timeout)) {
- list_add_tail(&transfer->list, &ctx->flying_transfers);
- goto out;
- }
-
- /* otherwise, find appropriate place in 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;
-
- if (!timerisset(cur_tv) || (cur_tv->tv_sec > timeout->tv_sec) ||
- (cur_tv->tv_sec == timeout->tv_sec &&
- cur_tv->tv_usec > timeout->tv_usec)) {
- list_add_tail(&transfer->list, &cur->list);
- r = first;
- goto out;
- }
- first = 0;
- }
-
- /* otherwise we need to be inserted at the end */
- list_add_tail(&transfer->list, &ctx->flying_transfers);
-out:
- usbi_mutex_unlock(&ctx->flying_transfers_lock);
- return r;
-}
-
/** \ingroup asyncio
* Allocate a libusb transfer with a specified number of isochronous packet
* descriptors. The returned transfer is pre-initialized for you. When the new
* \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);
+ struct libusb_transfer *transfer;
+ size_t os_alloc_size = usbi_backend->transfer_priv_size;
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;
usbi_mutex_init(&itransfer->lock, NULL);
- return __USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
+ usbi_mutex_init(&itransfer->flags_lock, NULL);
+ transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
+ usbi_dbg("transfer %p", transfer);
+ return transfer;
}
/** \ingroup asyncio
*
* \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)
return;
+ usbi_dbg("transfer %p", 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);
+ usbi_mutex_destroy(&itransfer->flags_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 on success 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_TIMEOUT_HANDLED)) {
+ 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 0;
+ }
+ }
+
+disarm:
+ return disarm_timerfd(ctx);
+}
+#else
+static int arm_timerfd_for_next_timeout(struct libusb_context *ctx)
+{
+ (void)ctx;
+ return 0;
+}
+#endif
+
+/* add a transfer to the (timeout-sorted) active transfers list.
+ * This function will return non 0 if fails to update the timer,
+ * in which case the transfer is *not* on the flying_transfers list. */
+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);
+ 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)) {
+ list_add(&transfer->list, &ctx->flying_transfers);
+ goto out;
+ }
+
+ /* 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, struct usbi_transfer) {
+ /* find first timeout that occurs after the transfer in question */
+ struct timeval *cur_tv = &cur->timeout;
+
+ if (!timerisset(cur_tv) || (cur_tv->tv_sec > timeout->tv_sec) ||
+ (cur_tv->tv_sec == timeout->tv_sec &&
+ cur_tv->tv_usec > timeout->tv_usec)) {
+ 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:
+#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},
+ { timeout->tv_sec, 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 (errno %d)", errno);
+ r = LIBUSB_ERROR_OTHER;
+ }
+ }
+#else
+ UNUSED(first);
+#endif
+
+ if (r)
+ list_del(&transfer->list);
+
+ usbi_mutex_unlock(&ctx->flying_transfers_lock);
+ return r;
+}
+
+/* remove a transfer from the active transfers list.
+ * This function will *always* remove the transfer from the
+ * flying_transfers list. It will return a LIBUSB_ERROR code
+ * if it fails to update the timer for the next timeout. */
+static int remove_from_flying_list(struct usbi_transfer *transfer)
+{
+ struct libusb_context *ctx = ITRANSFER_CTX(transfer);
+ int rearm_timerfd;
+ int r = 0;
+
+ usbi_mutex_lock(&ctx->flying_transfers_lock);
+ rearm_timerfd = (timerisset(&transfer->timeout) &&
+ list_first_entry(&ctx->flying_transfers, struct usbi_transfer, list) == transfer);
+ list_del(&transfer->list);
+ if (usbi_using_timerfd(ctx) && rearm_timerfd)
+ r = arm_timerfd_for_next_timeout(ctx);
+ usbi_mutex_unlock(&ctx->flying_transfers_lock);
+
+ return r;
+}
+
/** \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 remove = 0;
int r;
- int first;
+ usbi_dbg("transfer %p", transfer);
usbi_mutex_lock(&itransfer->lock);
+ usbi_mutex_lock(&itransfer->flags_lock);
+ if (itransfer->flags & USBI_TRANSFER_IN_FLIGHT) {
+ r = LIBUSB_ERROR_BUSY;
+ goto out;
+ }
itransfer->transferred = 0;
itransfer->flags = 0;
r = calculate_timeout(itransfer);
r = LIBUSB_ERROR_OTHER;
goto out;
}
+ itransfer->flags |= USBI_TRANSFER_SUBMITTING;
+ usbi_mutex_unlock(&itransfer->flags_lock);
- first = add_to_flying_list(itransfer);
- r = usbi_backend->submit_transfer(itransfer);
+ r = add_to_flying_list(itransfer);
if (r) {
- usbi_mutex_lock(&ctx->flying_transfers_lock);
- list_del(&itransfer->list);
- usbi_mutex_unlock(&ctx->flying_transfers_lock);
- }
-#ifdef USBI_TIMERFD_AVAILABLE
- else if (first && usbi_using_timerfd(ctx)) {
- /* 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},
- { itransfer->timeout.tv_sec, itransfer->timeout.tv_usec * 1000 } };
- usbi_dbg("arm timerfd for timeout in %dms (first in line)", transfer->timeout);
- r = timerfd_settime(ctx->timerfd, TFD_TIMER_ABSTIME, &it, NULL);
- if (r < 0)
- r = LIBUSB_ERROR_OTHER;
+ usbi_mutex_lock(&itransfer->flags_lock);
+ itransfer->flags = 0;
+ goto out;
}
-#endif
+ /* keep a reference to this device */
+ libusb_ref_device(transfer->dev_handle->dev);
+ r = usbi_backend->submit_transfer(itransfer);
+
+ usbi_mutex_lock(&itransfer->flags_lock);
+ itransfer->flags &= ~USBI_TRANSFER_SUBMITTING;
+ if (r == LIBUSB_SUCCESS) {
+ /* check for two possible special conditions:
+ * 1) device disconnect occurred immediately after submission
+ * 2) transfer completed before we got here to update the flags
+ */
+ if (itransfer->flags & USBI_TRANSFER_DEVICE_DISAPPEARED) {
+ usbi_backend->clear_transfer_priv(itransfer);
+ remove = 1;
+ r = LIBUSB_ERROR_NO_DEVICE;
+ }
+ else if (!(itransfer->flags & USBI_TRANSFER_COMPLETED)) {
+ itransfer->flags |= USBI_TRANSFER_IN_FLIGHT;
+ }
+ } else {
+ remove = 1;
+ }
out:
+ usbi_mutex_unlock(&itransfer->flags_lock);
+ if (remove) {
+ libusb_unref_device(transfer->dev_handle->dev);
+ remove_from_flying_list(itransfer);
+ }
usbi_mutex_unlock(&itransfer->lock);
return r;
}
*
* \param transfer the transfer to cancel
* \returns 0 on success
- * \returns LIBUSB_ERROR_NOT_FOUND if the transfer is already complete or
- * cancelled.
+ * \returns LIBUSB_ERROR_NOT_FOUND if the transfer is not in progress,
+ * already complete, or already 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_dbg("transfer %p", transfer );
usbi_mutex_lock(&itransfer->lock);
+ usbi_mutex_lock(&itransfer->flags_lock);
+ if (!(itransfer->flags & USBI_TRANSFER_IN_FLIGHT)
+ || (itransfer->flags & USBI_TRANSFER_CANCELLING)) {
+ r = LIBUSB_ERROR_NOT_FOUND;
+ goto out;
+ }
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 &&
+ r != LIBUSB_ERROR_NO_DEVICE)
+ 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;
+
+out:
+ usbi_mutex_unlock(&itransfer->flags_lock);
usbi_mutex_unlock(&itransfer->lock);
return r;
}
-#ifdef USBI_TIMERFD_AVAILABLE
-static int disarm_timerfd(struct libusb_context *ctx)
+/** \ingroup asyncio
+ * Set a transfers bulk stream id. Note users are advised to use
+ * libusb_fill_bulk_stream_transfer() instead of calling this function
+ * directly.
+ *
+ * Since version 1.0.19, \ref LIBUSB_API_VERSION >= 0x01000103
+ *
+ * \param transfer the transfer to set the stream id for
+ * \param stream_id the stream id to set
+ * \see libusb_alloc_streams()
+ */
+void API_EXPORTED libusb_transfer_set_stream_id(
+ struct libusb_transfer *transfer, uint32_t stream_id)
{
- const struct itimerspec disarm_timer = { { 0, 0 }, { 0, 0 } };
- int r;
+ struct usbi_transfer *itransfer =
+ LIBUSB_TRANSFER_TO_USBI_TRANSFER(transfer);
- usbi_dbg("");
- r = timerfd_settime(ctx->timerfd, 0, &disarm_timer, NULL);
- if (r < 0)
- return LIBUSB_ERROR_OTHER;
- else
- return 0;
+ itransfer->stream_id = stream_id;
}
-/* 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.
+/** \ingroup asyncio
+ * Get a transfers bulk stream id.
+ *
+ * Since version 1.0.19, \ref LIBUSB_API_VERSION >= 0x01000103
+ *
+ * \param transfer the transfer to get the stream id for
+ * \returns the stream id for the transfer
*/
-static int arm_timerfd_for_next_timeout(struct libusb_context *ctx)
+uint32_t API_EXPORTED libusb_transfer_get_stream_id(
+ struct libusb_transfer *transfer)
{
- 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))
- return 0;
-
- /* 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;
- }
- }
+ struct usbi_transfer *itransfer =
+ LIBUSB_TRANSFER_TO_USBI_TRANSFER(transfer);
- return 0;
+ return itransfer->stream_id;
}
-#else
-static int disarm_timerfd(struct libusb_context *ctx)
-{
- return 0;
-}
-static int arm_timerfd_for_next_timeout(struct libusb_context *ctx)
-{
- return 0;
-}
-#endif
/* Handle completion of a transfer (completion might be an error condition).
* This will invoke the user-supplied callback function, which may end up
enum libusb_transfer_status status)
{
struct libusb_transfer *transfer =
- __USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
- struct libusb_context *ctx = TRANSFER_CTX(transfer);
+ USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
+ struct libusb_device_handle *handle = transfer->dev_handle;
uint8_t flags;
int r;
- /* 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. */
+ r = remove_from_flying_list(itransfer);
+ if (r < 0)
+ usbi_err(ITRANSFER_CTX(itransfer), "failed to set timer for next timeout, errno=%d", errno);
- usbi_mutex_lock(&ctx->flying_transfers_lock);
- list_del(&itransfer->list);
- r = arm_timerfd_for_next_timeout(ctx);
- usbi_mutex_unlock(&ctx->flying_transfers_lock);
-
- if (r < 0) {
- return r;
- } else if (r == 0) {
- r = disarm_timerfd(ctx);
- if (r < 0)
- return r;
- }
+ usbi_mutex_lock(&itransfer->flags_lock);
+ itransfer->flags &= ~USBI_TRANSFER_IN_FLIGHT;
+ itransfer->flags |= USBI_TRANSFER_COMPLETED;
+ usbi_mutex_unlock(&itransfer->flags_lock);
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);
- usbi_mutex_lock(&ctx->event_waiters_lock);
- usbi_cond_broadcast(&ctx->event_waiters_cond);
- usbi_mutex_unlock(&ctx->event_waiters_lock);
- return 0;
+ libusb_unref_device(handle->dev);
+ return r;
}
/* Similar to usbi_handle_transfer_completion() but exclusively for transfers
return usbi_handle_transfer_completion(transfer, LIBUSB_TRANSFER_CANCELLED);
}
+/* Add a completed transfer to the completed_transfers list of the
+ * context and signal the event. The backend's handle_transfer_completion()
+ * function will be called the next time an event handler runs. */
+void usbi_signal_transfer_completion(struct usbi_transfer *transfer)
+{
+ struct libusb_context *ctx = ITRANSFER_CTX(transfer);
+ int pending_events;
+
+ usbi_mutex_lock(&ctx->event_data_lock);
+ pending_events = usbi_pending_events(ctx);
+ list_add_tail(&transfer->completed_list, &ctx->completed_transfers);
+ if (!pending_events)
+ usbi_signal_event(ctx);
+ usbi_mutex_unlock(&ctx->event_data_lock);
+}
+
/** \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.
* \param ctx the context to operate on, or NULL for the default context
* \returns 0 if the lock was obtained successfully
* \returns 1 if the lock was not obtained (i.e. another thread holds the lock)
- * \see \ref mtasync
+ * \ref mtasync
*/
-API_EXPORTED int libusb_try_lock_events(libusb_context *ctx)
+int API_EXPORTED libusb_try_lock_events(libusb_context *ctx)
{
int r;
+ unsigned int ru;
USBI_GET_CONTEXT(ctx);
- /* is someone else waiting to modify poll fds? if so, don't let this thread
+ /* is someone else waiting to close a device? if so, don't let this thread
* start event handling */
- usbi_mutex_lock(&ctx->pollfd_modify_lock);
- r = ctx->pollfd_modify;
- usbi_mutex_unlock(&ctx->pollfd_modify_lock);
- if (r) {
- usbi_dbg("someone else is modifying poll fds");
+ usbi_mutex_lock(&ctx->event_data_lock);
+ ru = ctx->device_close;
+ usbi_mutex_unlock(&ctx->event_data_lock);
+ if (ru) {
+ usbi_dbg("someone else is closing a device");
return 1;
}
* as soon as possible.
*
* \param ctx the context to operate on, or NULL for the default context
- * \see \ref mtasync
+ * \ref mtasync
*/
-API_EXPORTED void libusb_lock_events(libusb_context *ctx)
+void API_EXPORTED libusb_lock_events(libusb_context *ctx)
{
USBI_GET_CONTEXT(ctx);
usbi_mutex_lock(&ctx->events_lock);
* on libusb_wait_for_event().
*
* \param ctx the context to operate on, or NULL for the default context
- * \see \ref mtasync
+ * \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;
/* 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)? */
+ * (check ctx->device_close)? */
usbi_mutex_lock(&ctx->event_waiters_lock);
usbi_cond_broadcast(&ctx->event_waiters_cond);
usbi_mutex_unlock(&ctx->event_waiters_lock);
* \param ctx the context to operate on, or NULL for the default context
* \returns 1 if event handling can start or continue
* \returns 0 if this thread must give up the events lock
- * \see \ref fullstory "Multi-threaded I/O: the full story"
+ * \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;
+ unsigned int r;
USBI_GET_CONTEXT(ctx);
- /* is someone else waiting to modify poll fds? if so, don't let this thread
+ /* is someone else waiting to close a device? if so, don't let this thread
* continue event handling */
- usbi_mutex_lock(&ctx->pollfd_modify_lock);
- r = ctx->pollfd_modify;
- usbi_mutex_unlock(&ctx->pollfd_modify_lock);
+ usbi_mutex_lock(&ctx->event_data_lock);
+ r = ctx->device_close;
+ usbi_mutex_unlock(&ctx->event_data_lock);
if (r) {
- usbi_dbg("someone else is modifying poll fds");
+ usbi_dbg("someone else is closing a device");
return 0;
}
* \param ctx the context to operate on, or NULL for the default context
* \returns 1 if a thread is handling events
* \returns 0 if there are no threads currently handling events
- * \see \ref mtasync
+ * \ref mtasync
*/
-API_EXPORTED int libusb_event_handler_active(libusb_context *ctx)
+int API_EXPORTED libusb_event_handler_active(libusb_context *ctx)
{
- int r;
+ unsigned int r;
USBI_GET_CONTEXT(ctx);
- /* is someone else waiting to modify poll fds? if so, don't let this thread
+ /* is someone else waiting to close a device? if so, don't let this thread
* start event handling -- indicate that event handling is happening */
- usbi_mutex_lock(&ctx->pollfd_modify_lock);
- r = ctx->pollfd_modify;
- usbi_mutex_unlock(&ctx->pollfd_modify_lock);
+ usbi_mutex_lock(&ctx->event_data_lock);
+ r = ctx->device_close;
+ usbi_mutex_unlock(&ctx->event_data_lock);
if (r) {
- usbi_dbg("someone else is modifying poll fds");
+ usbi_dbg("someone else is closing a device");
return 1;
}
* locking.
*
* \param ctx the context to operate on, or NULL for the default context
- * \see \ref mtasync
+ * \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);
usbi_mutex_lock(&ctx->event_waiters_lock);
/** \ingroup poll
* Release the event waiters lock.
* \param ctx the context to operate on, or NULL for the default context
- * \see \ref mtasync
+ * \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);
usbi_mutex_unlock(&ctx->event_waiters_lock);
* indicates unlimited timeout.
* \returns 0 after a transfer completes or another thread stops event handling
* \returns 1 if the timeout expired
- * \see \ref mtasync
+ * \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;
timeout.tv_sec += tv->tv_sec;
timeout.tv_nsec += tv->tv_usec * 1000;
- if (timeout.tv_nsec > 1000000000) {
+ while (timeout.tv_nsec >= 1000000000) {
timeout.tv_nsec -= 1000000000;
timeout.tv_sec++;
}
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;
+ itransfer->flags |= USBI_TRANSFER_TIMEOUT_HANDLED;
r = libusb_cancel_transfer(transfer);
- if (r < 0)
+ if (r == 0)
+ itransfer->flags |= USBI_TRANSFER_TIMED_OUT;
+ else
usbi_warn(TRANSFER_CTX(transfer),
"async cancel failed %d errno=%d", r, errno);
}
-#ifdef USBI_OS_HANDLES_TIMEOUT
-static int handle_timeouts_locked(struct libusb_context *ctx)
-{
- return 0;
-}
-static int handle_timeouts(struct libusb_context *ctx)
-{
- return 0;
-}
-#else
static int handle_timeouts_locked(struct libusb_context *ctx)
{
int r;
return 0;
/* ignore timeouts we've already handled */
- if (transfer->flags & USBI_TRANSFER_TIMED_OUT)
+ if (transfer->flags & (USBI_TRANSFER_TIMEOUT_HANDLED | USBI_TRANSFER_OS_HANDLES_TIMEOUT))
continue;
/* if transfer has non-expired timeout, nothing more to do */
usbi_mutex_unlock(&ctx->flying_transfers_lock);
return r;
}
-#endif
#ifdef USBI_TIMERFD_AVAILABLE
static int handle_timerfd_trigger(struct libusb_context *ctx)
{
int r;
- r = disarm_timerfd(ctx);
- if (r < 0)
- return r;
-
usbi_mutex_lock(&ctx->flying_transfers_lock);
/* process the timeout that just happened */
{
int r;
struct usbi_pollfd *ipollfd;
- nfds_t nfds = 0;
- struct pollfd *fds;
+ POLL_NFDS_TYPE nfds = 0;
+ POLL_NFDS_TYPE internal_nfds;
+ struct pollfd *fds = NULL;
int i = -1;
int timeout_ms;
+ int special_event;
- usbi_mutex_lock(&ctx->pollfds_lock);
- list_for_each_entry(ipollfd, &ctx->pollfds, list, struct usbi_pollfd)
- nfds++;
+ /* there are certain fds that libusb uses internally, currently:
+ *
+ * 1) event pipe
+ * 2) timerfd
+ *
+ * the backend will never need to attempt to handle events on these fds, so
+ * we determine how many fds are in use internally for this context and when
+ * handle_events() is called in the backend, the pollfd list and count will
+ * be adjusted to skip over these internal fds */
+ if (usbi_using_timerfd(ctx))
+ internal_nfds = 2;
+ else
+ internal_nfds = 1;
- /* TODO: malloc when number of fd's changes, not on every poll */
- fds = malloc(sizeof(*fds) * nfds);
- if (!fds) {
- usbi_mutex_unlock(&ctx->pollfds_lock);
- return LIBUSB_ERROR_NO_MEM;
- }
+ /* only reallocate the poll fds when the list of poll fds has been modified
+ * since the last poll, otherwise reuse them to save the additional overhead */
+ usbi_mutex_lock(&ctx->event_data_lock);
+ if (ctx->pollfds_modified) {
+ usbi_dbg("poll fds modified, reallocating");
+
+ if (ctx->pollfds) {
+ free(ctx->pollfds);
+ ctx->pollfds = NULL;
+ }
- list_for_each_entry(ipollfd, &ctx->pollfds, list, struct usbi_pollfd) {
- struct libusb_pollfd *pollfd = &ipollfd->pollfd;
- int fd = pollfd->fd;
- i++;
- fds[i].fd = fd;
- fds[i].events = pollfd->events;
- fds[i].revents = 0;
+ /* sanity check - it is invalid for a context to have fewer than the
+ * required internal fds (memory corruption?) */
+ assert(ctx->pollfds_cnt >= internal_nfds);
+
+ ctx->pollfds = calloc(ctx->pollfds_cnt, sizeof(*ctx->pollfds));
+ if (!ctx->pollfds) {
+ usbi_mutex_unlock(&ctx->event_data_lock);
+ return LIBUSB_ERROR_NO_MEM;
+ }
+
+ list_for_each_entry(ipollfd, &ctx->ipollfds, list, struct usbi_pollfd) {
+ struct libusb_pollfd *pollfd = &ipollfd->pollfd;
+ i++;
+ ctx->pollfds[i].fd = pollfd->fd;
+ ctx->pollfds[i].events = pollfd->events;
+ }
+
+ /* reset the flag now that we have the updated list */
+ ctx->pollfds_modified = 0;
+
+ /* if no further pending events, clear the event pipe so that we do
+ * not immediately return from poll */
+ if (!usbi_pending_events(ctx))
+ usbi_clear_event(ctx);
}
- usbi_mutex_unlock(&ctx->pollfds_lock);
+ fds = ctx->pollfds;
+ nfds = ctx->pollfds_cnt;
+ usbi_mutex_unlock(&ctx->event_data_lock);
- timeout_ms = (tv->tv_sec * 1000) + (tv->tv_usec / 1000);
+ timeout_ms = (int)(tv->tv_sec * 1000) + (tv->tv_usec / 1000);
/* round up to next millisecond */
if (tv->tv_usec % 1000)
timeout_ms++;
+redo_poll:
usbi_dbg("poll() %d fds with timeout in %dms", nfds, timeout_ms);
r = usbi_poll(fds, nfds, timeout_ms);
usbi_dbg("poll() returned %d", r);
- if (r == 0) {
- free(fds);
+ if (r == 0)
return handle_timeouts(ctx);
- } else if (r == -1 && errno == EINTR) {
- free(fds);
+ else if (r == -1 && errno == EINTR)
return LIBUSB_ERROR_INTERRUPTED;
- } else if (r < 0) {
- free(fds);
- usbi_err(ctx, "poll failed %d err=%d\n", r, errno);
+ else if (r < 0) {
+ usbi_err(ctx, "poll failed %d err=%d", r, errno);
return LIBUSB_ERROR_IO;
}
- /* fd[0] is always the ctrl pipe */
+ special_event = 0;
+
+ /* fds[0] is always the event pipe */
if (fds[0].revents) {
- /* another thread wanted to interrupt event handling, and it succeeded!
- * handle any other events that cropped up at the same time, and
- * simply return */
- usbi_dbg("caught a fish on the control pipe");
+ libusb_hotplug_message *message = NULL;
+ struct usbi_transfer *itransfer;
+ int ret = 0;
+
+ usbi_dbg("caught a fish on the event pipe");
+
+ /* take the the event data lock while processing events */
+ usbi_mutex_lock(&ctx->event_data_lock);
+
+ /* check if someone added a new poll fd */
+ if (ctx->pollfds_modified)
+ usbi_dbg("someone updated the poll fds");
+
+ /* check if someone is closing a device */
+ if (ctx->device_close)
+ usbi_dbg("someone is closing a device");
+
+ /* check for any pending hotplug messages */
+ if (!list_empty(&ctx->hotplug_msgs)) {
+ usbi_dbg("hotplug message received");
+ special_event = 1;
+ message = list_first_entry(&ctx->hotplug_msgs, libusb_hotplug_message, list);
+ list_del(&message->list);
+ }
+
+ /* complete any pending transfers */
+ while (ret == 0 && !list_empty(&ctx->completed_transfers)) {
+ itransfer = list_first_entry(&ctx->completed_transfers, struct usbi_transfer, completed_list);
+ list_del(&itransfer->completed_list);
+ usbi_mutex_unlock(&ctx->event_data_lock);
+ ret = usbi_backend->handle_transfer_completion(itransfer);
+ if (ret)
+ usbi_err(ctx, "backend handle_transfer_completion failed with error %d", ret);
+ usbi_mutex_lock(&ctx->event_data_lock);
+ }
- if (r == 1) {
- r = 0;
+ /* if no further pending events, clear the event pipe */
+ if (!usbi_pending_events(ctx))
+ usbi_clear_event(ctx);
+
+ usbi_mutex_unlock(&ctx->event_data_lock);
+
+ /* process the hotplug message, if any */
+ if (message) {
+ usbi_hotplug_match(ctx, message->device, message->event);
+
+ /* the device left, dereference the device */
+ if (LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT == message->event)
+ libusb_unref_device(message->device);
+
+ free(message);
+ }
+
+ if (ret) {
+ /* return error code */
+ r = ret;
goto handled;
- } else {
- /* prevent OS backend from trying to handle events on ctrl pipe */
- fds[0].revents = 0;
- r--;
}
+
+ if (0 == --r)
+ goto handled;
}
#ifdef USBI_TIMERFD_AVAILABLE
/* timerfd indicates that a timeout has expired */
int ret;
usbi_dbg("timerfd triggered");
+ special_event = 1;
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--;
}
+
+ if (0 == --r)
+ goto handled;
}
#endif
- r = usbi_backend->handle_events(ctx, fds, nfds, r);
+ r = usbi_backend->handle_events(ctx, fds + internal_nfds, nfds - internal_nfds, r);
if (r)
usbi_err(ctx, "backend handle_events failed with error %d", r);
handled:
- free(fds);
+ if (r == 0 && special_event) {
+ timeout_ms = 0;
+ goto redo_poll;
+ }
+
return r;
}
* 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
+ * \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
+ *
+ * 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() instead.
+ * 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
+ * \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 = 60;
tv.tv_usec = 0;
- return libusb_handle_events_timeout(ctx, &tv);
+ return libusb_handle_events_timeout_completed(ctx, &tv, completed);
}
/** \ingroup poll
* \param tv the maximum time to block waiting for events, or zero for
* non-blocking mode
* \returns 0 on success, or a LIBUSB_ERROR code on failure
- * \see \ref mtasync
+ * \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;
* \returns 0 if you must call into libusb 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 libusb file descriptors for event handling"
+ * \ref pollmain "Polling libusb file descriptors for event handling"
*/
-API_EXPORTED int libusb_pollfds_handle_timeouts(libusb_context *ctx)
+int API_EXPORTED libusb_pollfds_handle_timeouts(libusb_context *ctx)
{
-#if defined(USBI_OS_HANDLES_TIMEOUT)
- return 1;
-#elif defined(USBI_TIMERFD_AVAILABLE)
+#if defined(USBI_TIMERFD_AVAILABLE)
USBI_GET_CONTEXT(ctx);
return usbi_using_timerfd(ctx);
#else
+ (void)ctx;
return 0;
#endif
}
* \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)
{
-#ifndef USBI_OS_HANDLES_TIMEOUT
struct usbi_transfer *transfer;
struct timespec cur_ts;
struct timeval cur_tv;
- struct timeval *next_timeout;
+ struct timeval next_timeout = { 0, 0 };
int r;
- int found = 0;
USBI_GET_CONTEXT(ctx);
if (usbi_using_timerfd(ctx))
/* find next transfer which hasn't already been processed as timed out */
list_for_each_entry(transfer, &ctx->flying_transfers, list, struct usbi_transfer) {
- if (!(transfer->flags & USBI_TRANSFER_TIMED_OUT)) {
- found = 1;
+ if (transfer->flags & (USBI_TRANSFER_TIMEOUT_HANDLED | USBI_TRANSFER_OS_HANDLES_TIMEOUT))
+ continue;
+
+ /* if we've reached transfers of infinte timeout, we're done looking */
+ if (!timerisset(&transfer->timeout))
break;
- }
- }
- usbi_mutex_unlock(&ctx->flying_transfers_lock);
- if (!found) {
- usbi_dbg("all URBs have already been processed for timeouts");
- return 0;
+ next_timeout = transfer->timeout;
+ break;
}
+ usbi_mutex_unlock(&ctx->flying_transfers_lock);
- next_timeout = &transfer->timeout;
-
- /* no timeout for next transfer */
- if (!timerisset(next_timeout)) {
- usbi_dbg("no URBs with timeouts, no timeout!");
+ if (!timerisset(&next_timeout)) {
+ usbi_dbg("no URB with timeout or all handled by OS; no timeout!");
return 0;
}
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 {
- timersub(next_timeout, &cur_tv, tv);
+ timersub(&next_timeout, &cur_tv, tv);
usbi_dbg("next timeout in %d.%06ds", tv->tv_sec, tv->tv_usec);
}
return 1;
-#else
- return 0;
-#endif
}
/** \ingroup poll
* \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)
{
ctx->fd_cb_user_data = user_data;
}
+/*
+ * Interrupt the iteration of the event handling thread, so that it picks
+ * up the fd change. Callers of this function must hold the event_data_lock.
+ */
+static void usbi_fd_notification(struct libusb_context *ctx)
+{
+ int pending_events;
+
+ /* Record that there is a new poll fd.
+ * Only signal an event if there are no prior pending events. */
+ pending_events = usbi_pending_events(ctx);
+ ctx->pollfds_modified = 1;
+ if (!pending_events)
+ usbi_signal_event(ctx);
+}
+
/* Add a file descriptor to the list of file descriptors to be monitored.
* events should be specified as a bitmask of events passed to poll(), e.g.
* POLLIN and/or POLLOUT. */
usbi_dbg("add fd %d events %d", fd, events);
ipollfd->pollfd.fd = fd;
ipollfd->pollfd.events = events;
- usbi_mutex_lock(&ctx->pollfds_lock);
- list_add_tail(&ipollfd->list, &ctx->pollfds);
- usbi_mutex_unlock(&ctx->pollfds_lock);
+ usbi_mutex_lock(&ctx->event_data_lock);
+ list_add_tail(&ipollfd->list, &ctx->ipollfds);
+ ctx->pollfds_cnt++;
+ usbi_fd_notification(ctx);
+ usbi_mutex_unlock(&ctx->event_data_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);
- usbi_mutex_lock(&ctx->pollfds_lock);
- list_for_each_entry(ipollfd, &ctx->pollfds, list, struct usbi_pollfd)
+ usbi_mutex_lock(&ctx->event_data_lock);
+ list_for_each_entry(ipollfd, &ctx->ipollfds, list, struct usbi_pollfd)
if (ipollfd->pollfd.fd == fd) {
found = 1;
break;
if (!found) {
usbi_dbg("couldn't find fd %d to remove", fd);
- usbi_mutex_unlock(&ctx->pollfds_lock);
+ usbi_mutex_unlock(&ctx->event_data_lock);
return;
}
list_del(&ipollfd->list);
- usbi_mutex_unlock(&ctx->pollfds_lock);
+ ctx->pollfds_cnt--;
+ usbi_fd_notification(ctx);
+ usbi_mutex_unlock(&ctx->event_data_lock);
free(ipollfd);
if (ctx->fd_removed_cb)
ctx->fd_removed_cb(fd, ctx->fd_cb_user_data);
* Retrieve a list of file descriptors that should be polled by your main loop
* as libusb event sources.
*
- * The returned list is NULL-terminated and should be freed with free() when
- * done. The actual list contents must not be touched.
+ * The returned list is NULL-terminated and should be freed with libusb_free_pollfds()
+ * 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);
- usbi_mutex_lock(&ctx->pollfds_lock);
- list_for_each_entry(ipollfd, &ctx->pollfds, list, struct usbi_pollfd)
- cnt++;
+ usbi_mutex_lock(&ctx->event_data_lock);
- ret = calloc(cnt + 1, sizeof(struct libusb_pollfd *));
+ ret = calloc(ctx->pollfds_cnt + 1, sizeof(struct libusb_pollfd *));
if (!ret)
goto out;
- list_for_each_entry(ipollfd, &ctx->pollfds, list, struct usbi_pollfd)
+ list_for_each_entry(ipollfd, &ctx->ipollfds, list, struct usbi_pollfd)
ret[i++] = (struct libusb_pollfd *) ipollfd;
- ret[cnt] = NULL;
+ ret[ctx->pollfds_cnt] = NULL;
out:
- usbi_mutex_unlock(&ctx->pollfds_lock);
+ usbi_mutex_unlock(&ctx->event_data_lock);
return (const struct libusb_pollfd **) ret;
+#else
+ usbi_err(ctx, "external polling of libusb'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.
- * The transfers get cancelled appropriately.
+/** \ingroup poll
+ * Free a list of libusb_pollfd structures. This should be called for all
+ * pollfd lists allocated with libusb_get_pollfds().
+ *
+ * Since version 1.0.20, \ref LIBUSB_API_VERSION >= 0x01000104
+ *
+ * It is legal to call this function with a NULL pollfd list. In this case,
+ * the function will simply return safely.
+ *
+ * \param pollfds the list of libusb_pollfd structures to free
+ */
+void API_EXPORTED libusb_free_pollfds(const struct libusb_pollfd **pollfds)
+{
+ if (!pollfds)
+ return;
+
+ free((void *)pollfds);
+}
+
+/* Backends may call this from handle_events to report disconnection of a
+ * device. This function ensures transfers get cancelled appropriately.
+ * Callers of this function must hold the events_lock.
*/
void usbi_handle_disconnect(struct libusb_device_handle *handle)
{
/* 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
- * list of transfers to complete (while holding look), the situation
- * might be different by the time we come to free them
- *
- * so we resort to a loop-based approach as below
- * FIXME: is this still potentially racy?
+ * when we find a transfer for this device on the list, there are two
+ * possible scenarios:
+ * 1. the transfer is currently in-flight, in which case we terminate the
+ * transfer here
+ * 2. the transfer is not in-flight (or is but hasn't been marked as such),
+ * in which case we record that the device disappeared and this will be
+ * handled by libusb_submit_transfer()
*/
while (1) {
- usbi_mutex_lock(&HANDLE_CTX(handle)->flying_transfers_lock);
to_cancel = NULL;
+ usbi_mutex_lock(&HANDLE_CTX(handle)->flying_transfers_lock);
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;
+ if (USBI_TRANSFER_TO_LIBUSB_TRANSFER(cur)->dev_handle == handle) {
+ usbi_mutex_lock(&cur->flags_lock);
+ if (cur->flags & USBI_TRANSFER_IN_FLIGHT)
+ to_cancel = cur;
+ else
+ cur->flags |= USBI_TRANSFER_DEVICE_DISAPPEARED;
+ usbi_mutex_unlock(&cur->flags_lock);
+
+ if (to_cancel)
+ break;
}
usbi_mutex_unlock(&HANDLE_CTX(handle)->flying_transfers_lock);
if (!to_cancel)
break;
+ usbi_dbg("cancelling transfer %p from disconnect",
+ USBI_TRANSFER_TO_LIBUSB_TRANSFER(to_cancel));
+
+ usbi_mutex_lock(&to_cancel->lock);
usbi_backend->clear_transfer_priv(to_cancel);
+ usbi_mutex_unlock(&to_cancel->lock);
usbi_handle_transfer_completion(to_cancel, LIBUSB_TRANSFER_NO_DEVICE);
}
}
-
projects / platform / upstream / libusb.git / blobdiff