* I/O functions for libusb
* Copyright © 2007-2009 Daniel Drake <dsd@gentoo.org>
* Copyright © 2001 Johannes Erdfelt <johannes@erdfelt.com>
+ * Copyright © 2019 Nathan Hjelm <hjelmn@cs.umm.edu>
+ * Copyright © 2019 Google LLC. All rights reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
-#include <config.h>
-
-#include <assert.h>
-#include <errno.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
+ * \page libusb_io Synchronous and asynchronous device I/O
*
* \section io_intro Introduction
*
*
* Once you have read through the following discussion, you should consult the
* detailed API documentation pages for the details:
- * - \ref syncio
- * - \ref asyncio
+ * - \ref libusb_syncio
+ * - \ref libusb_asyncio
*
* \section theory Transfers at a logical level
*
* a single function call. When the function call returns, the transfer has
* completed and you can parse the results.
*
- * If you have used the libusb-0.1 before, this I/O style will seem familar to
+ * If you have used the libusb-0.1 before, this I/O style will seem familiar to
* you. libusb-0.1 only offered a synchronous interface.
*
* In our input device example, to read button presses you might write code
\code
unsigned char data[4];
int actual_length;
-int r = libusb_bulk_transfer(handle, LIBUSB_ENDPOINT_IN, data, sizeof(data), &actual_length, 0);
+int r = libusb_bulk_transfer(dev_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
* sleeping for that long. Execution will be tied up inside the library -
* the entire thread will be useless for that duration.
*
- * Another issue is that by tieing up the thread with that single transaction
+ * Another issue is that by tying up the thread with that single transaction
* there is no possibility of performing I/O with multiple endpoints and/or
* multiple devices simultaneously, unless you resort to creating one thread
* per transaction.
* request has been submitted.
*
* For details on how to use the synchronous API, see the
- * \ref syncio "synchronous I/O API documentation" pages.
+ * \ref libusb_syncio "synchronous I/O API documentation" pages.
*
* \section async The asynchronous interface
*
* calls to the asynchronous interface.
*
* For details on how to use the asynchronous API, see the
- * \ref asyncio "asynchronous I/O API" documentation pages.
+ * \ref libusb_asyncio "asynchronous I/O API" documentation pages.
*/
/**
- * \page packetoverflow Packets and overflows
+ * \page libusb_packetoverflow Packets and overflows
*
* \section packets Packet abstraction
*
*/
/**
- * @defgroup asyncio Asynchronous device I/O
+ * @defgroup libusb_asyncio Asynchronous device I/O
*
* This page details libusb'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
- * may wish to consider the \ref syncio "synchronous I/O API" instead.
+ * may wish to consider the \ref libusb_syncio "synchronous I/O API" instead.
*
* The asynchronous interface is built around the idea of separating transfer
* submission and handling of transfer completion (the synchronous model
* success or failure reason, number of bytes of data transferred, etc. See
* the libusb_transfer structure documentation for more information.
*
+ * <b>Important Note</b>: The user-specified callback is called from an event
+ * handling context. It is therefore important that no calls are made into
+ * libusb that will attempt to perform any event handling. Examples of such
+ * functions are any listed in the \ref libusb_syncio "synchronous API" and any of
+ * the blocking functions that retrieve \ref libusb_desc "USB descriptors".
+ *
* \subsection Deallocation
*
* When a transfer has completed (i.e. the callback function has been invoked),
* Freeing the transfer after it has been cancelled but before cancellation
* has completed will result in undefined behaviour.
*
+ * \attention
* When a transfer is cancelled, some of the data may have been transferred.
- * libusb will communicate this to you in the transfer callback. Do not assume
- * that no data was transferred.
+ * libusb will communicate this to you in the transfer callback.
+ * <b>Do not assume that no data was transferred.</b>
+ *
+ * \section asyncpartial Partial data transfer resulting from cancellation
+ *
+ * As noted above, some of the data may have been transferred at the time a
+ * transfer is cancelled. It is helpful to see how this is possible if you
+ * consider a bulk transfer to an endpoint with a packet size of 64 bytes.
+ * Supposing you submit a 512-byte transfer to this endpoint, the operating
+ * system will divide this transfer up into 8 separate 64-byte frames that the
+ * host controller will schedule for the device to transfer data. If this
+ * transfer is cancelled while the device is transferring data, a subset of
+ * these frames may be descheduled from the host controller before the device
+ * has the opportunity to finish transferring data to the host.
+ *
+ * What your application should do with a partial data transfer is a policy
+ * decision; there is no single answer that satisfies the needs of every
+ * application. The data that was successfully transferred should be
+ * considered entirely valid, but your application must decide what to do with
+ * the remaining data that was not transferred. Some possible actions to take
+ * are:
+ * - Resubmit another transfer for the remaining data, possibly with a shorter
+ * timeout
+ * - Discard the partially transferred data and report an error
+ *
+ * \section asynctimeout Timeouts
+ *
+ * When a transfer times out, libusb internally notes this and attempts to
+ * cancel the transfer. As noted in \ref asyncpartial "above", it is possible
+ * that some of the data may actually have been transferred. Your application
+ * should <b>always</b> check how much data was actually transferred once the
+ * transfer completes and act accordingly.
*
* \section bulk_overflows Overflows on device-to-host bulk/interrupt endpoints
*
* your application may submit a request for data on an IN endpoint which is
* smaller than the data that the device wishes to send. In some circumstances
* this will cause an overflow, which is a nasty condition to deal with. See
- * the \ref packetoverflow page for discussion.
+ * the \ref libusb_packetoverflow page for discussion.
*
* \section asyncctrl Considerations for control transfers
*
* wLength of the setup packet, rather than the size of the data buffer. So,
* if your wLength was 4, your transfer's <tt>length</tt> was 12, then you
* should expect an <tt>actual_length</tt> of 4 to indicate that the data was
- * transferred in entirity.
+ * transferred in entirety.
*
* To simplify parsing of setup packets and obtaining the data from the
* correct offset, you may wish to use the libusb_control_transfer_get_data()
* 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,
+ * \section asynclimits Transfer length limitations
+ *
+ * Some operating systems may impose limits on the length of the transfer data
+ * buffer or, in the case of isochronous transfers, the length of individual
+ * isochronous packets. Such limits can be difficult for libusb to detect, so
+ * in most cases 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".
*
+ * The following are known limits for control transfer lengths. Note that this
+ * length includes the 8-byte setup packet.
+ * - Linux (4,096 bytes)
+ * - Windows (4,096 bytes)
+ *
* \section asyncmem Memory caveats
*
* In most circumstances, it is not safe to use stack memory for transfer
* application must call into when libusb has work do to. This gives libusb
* the opportunity to reap pending transfers, invoke callbacks, etc.
*
- * There are 2 different approaches to dealing with libusb_handle_events:
+ * \note
+ * All event handling is performed by whichever thread calls the
+ * libusb_handle_events() function. libusb does not invoke any callbacks
+ * outside of this context. Consequently, any callbacks will be run on the
+ * thread that calls the libusb_handle_events() function.
+ *
+ * When to call the libusb_handle_events() function depends on which model
+ * your application decides to use. The 2 different approaches:
*
* -# Repeatedly call libusb_handle_events() in blocking mode from a dedicated
* thread.
* below for details.
*
* 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
+ * see the \ref libusb_poll "polling and timing" section for how to integrate libusb
* into your application's main event loop.
*
* \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.
+ * thread-safe.
*
* Other then that doing event handling from a separate thread, is mostly
* simple. You can use an event thread function as follows:
* 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.
+ * application uses libusb' \ref libusb_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)
+void my_close_handle(libusb_device_handle *dev_handle)
{
if (open_devs == 1)
event_thread_run = 0;
- libusb_close(handle); // This wakes up libusb_handle_events()
+ libusb_close(dev_handle); // This wakes up libusb_handle_events()
if (open_devs == 1)
pthread_join(event_thread);
* 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);
*/
/**
- * @defgroup poll Polling and timing
+ * @defgroup libusb_poll Polling and timing
*
* This page documents libusb'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
+ * \ref libusb_asyncio "asynchronous API". If you are only using the simpler
+ * \ref libusb_syncio "synchronous API" then you do not need to ever call these
* functions.
*
* The justification for the functionality described here has already been
* 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.
* sets of file descriptors or handling timeouts. libusb_handle_events() will
* handle those details internally.
*
- * \section pollmain The more advanced option
+ * \section libusb_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
* entities are added to solve these problems. You do not need to be concerned
* with these entities otherwise.
*
- * See the extra documentation: \ref mtasync
+ * See the extra documentation: \ref libusb_mtasync
*/
-/** \page mtasync Multi-threaded applications and asynchronous I/O
+/** \page libusb_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.
* The underlying issue that must be addressed is that all libusb 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
- * \ref syncio "synchronous interface" is implemented on top of the
- * asynchonrous interface, therefore the same considerations apply.
+ * \ref libusb_asyncio "asynchronous interface" but it is important to note that the
+ * \ref libusb_syncio "synchronous interface" is implemented on top of the
+ * asynchronous 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
* do is submit a single transfer and wait for its completion, then using
* one of the synchronous I/O functions is much easier.
*
+ * \note
+ * The `completed` variable must be modified while holding the event lock,
+ * otherwise a race condition can still exist. It is simplest to do so from
+ * within the transfer callback as shown above.
+ *
* \section eventlock The events lock
*
* The problem is when we consider the fact that libusb exposes file
* event handling), because the event waiter seems to have taken the event
* waiters lock while waiting for an event. However, the system does support
* multiple event waiters, because libusb_wait_for_event() actually drops
- * the lock while waiting, and reaquires it before continuing.
+ * the lock while waiting, and reacquires it before continuing.
*
* We have now implemented code which can dynamically handle situations where
* nobody is handling events (so we should do it ourselves), and it can also
* (without implementing the rules and locking semantics documented above)
* and another trying to send a synchronous USB transfer, you will end up with
* two threads monitoring the same descriptors, and the above-described
- * undesirable behaviour occuring. The solution is for your polling thread to
+ * undesirable behaviour occurring. The solution is for your polling thread to
* play by the rules; the synchronous I/O functions do so, and this will result
* in them getting along in perfect harmony.
*
{
int r;
- usbi_mutex_init(&ctx->flying_transfers_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);
+ usbi_mutex_init(&ctx->flying_transfers_lock);
+ usbi_mutex_init(&ctx->events_lock);
+ usbi_mutex_init(&ctx->event_waiters_lock);
+ usbi_cond_init(&ctx->event_waiters_cond);
+ usbi_mutex_init(&ctx->event_data_lock);
+ usbi_tls_key_create(&ctx->event_handling_key);
list_init(&ctx->flying_transfers);
- list_init(&ctx->ipollfds);
+ list_init(&ctx->event_sources);
+ list_init(&ctx->removed_event_sources);
list_init(&ctx->hotplug_msgs);
list_init(&ctx->completed_transfers);
- /* FIXME should use an eventfd on kernels that support it */
- r = usbi_pipe(ctx->event_pipe);
- if (r < 0) {
- r = LIBUSB_ERROR_OTHER;
+ r = usbi_create_event(&ctx->event);
+ if (r < 0)
goto err;
- }
- r = usbi_add_pollfd(ctx, ctx->event_pipe[0], POLLIN);
+ r = usbi_add_event_source(ctx, USBI_EVENT_OS_HANDLE(&ctx->event), USBI_EVENT_POLL_EVENTS);
if (r < 0)
- 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);
+ goto err_destroy_event;
+
+#ifdef HAVE_OS_TIMER
+ r = usbi_create_timer(&ctx->timer);
+ if (r == 0) {
+ usbi_dbg(ctx, "using timer for timeouts");
+ r = usbi_add_event_source(ctx, USBI_TIMER_OS_HANDLE(&ctx->timer), USBI_TIMER_POLL_EVENTS);
if (r < 0)
- goto err_close_timerfd;
+ goto err_destroy_timer;
} else {
- usbi_dbg("timerfd not available (code %d error %d)", ctx->timerfd, errno);
- ctx->timerfd = -1;
+ usbi_dbg(ctx, "timer not available for timeouts");
}
#endif
return 0;
-#ifdef USBI_TIMERFD_AVAILABLE
-err_close_timerfd:
- close(ctx->timerfd);
- usbi_remove_pollfd(ctx, ctx->event_pipe[0]);
+#ifdef HAVE_OS_TIMER
+err_destroy_timer:
+ usbi_destroy_timer(&ctx->timer);
+ usbi_remove_event_source(ctx, USBI_EVENT_OS_HANDLE(&ctx->event));
#endif
-err_close_pipe:
- usbi_close(ctx->event_pipe[0]);
- usbi_close(ctx->event_pipe[1]);
+err_destroy_event:
+ usbi_destroy_event(&ctx->event);
err:
usbi_mutex_destroy(&ctx->flying_transfers_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);
+ usbi_tls_key_delete(ctx->event_handling_key);
return r;
}
+static void cleanup_removed_event_sources(struct libusb_context *ctx)
+{
+ struct usbi_event_source *ievent_source, *tmp;
+
+ for_each_removed_event_source_safe(ctx, ievent_source, tmp) {
+ list_del(&ievent_source->list);
+ free(ievent_source);
+ }
+}
+
void usbi_io_exit(struct libusb_context *ctx)
{
- 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);
- close(ctx->timerfd);
+#ifdef HAVE_OS_TIMER
+ if (usbi_using_timer(ctx)) {
+ usbi_remove_event_source(ctx, USBI_TIMER_OS_HANDLE(&ctx->timer));
+ usbi_destroy_timer(&ctx->timer);
}
#endif
+ usbi_remove_event_source(ctx, USBI_EVENT_OS_HANDLE(&ctx->event));
+ usbi_destroy_event(&ctx->event);
usbi_mutex_destroy(&ctx->flying_transfers_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);
+ usbi_tls_key_delete(ctx->event_handling_key);
+ cleanup_removed_event_sources(ctx);
+ free(ctx->event_data);
}
-static int calculate_timeout(struct usbi_transfer *transfer)
+static void calculate_timeout(struct usbi_transfer *itransfer)
{
- int r;
- struct timespec current_time;
unsigned int timeout =
- USBI_TRANSFER_TO_LIBUSB_TRANSFER(transfer)->timeout;
+ USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer)->timeout;
- if (!timeout)
- return 0;
-
- 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 r;
- }
-
- current_time.tv_sec += timeout / 1000;
- current_time.tv_nsec += (timeout % 1000) * 1000000;
-
- while (current_time.tv_nsec >= 1000000000) {
- current_time.tv_nsec -= 1000000000;
- current_time.tv_sec++;
- }
-
- TIMESPEC_TO_TIMEVAL(&transfer->timeout, ¤t_time);
- return 0;
-}
-
-/* add a transfer to the (timeout-sorted) active transfers list.
- * Callers of this function must hold the flying_transfers_lock.
- * This function *always* adds the transfer to the flying_transfers list,
- * it will return non 0 if it fails to update the timer, but even then the
- * transfer is added to 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;
-
- /* 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 (!timeout) {
+ TIMESPEC_CLEAR(&itransfer->timeout);
+ return;
}
- /* 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;
- }
+ usbi_get_monotonic_time(&itransfer->timeout);
- /* 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;
+ itransfer->timeout.tv_sec += timeout / 1000U;
+ itransfer->timeout.tv_nsec += (timeout % 1000U) * 1000000L;
+ if (itransfer->timeout.tv_nsec >= NSEC_PER_SEC) {
+ ++itransfer->timeout.tv_sec;
+ itransfer->timeout.tv_nsec -= NSEC_PER_SEC;
}
- /* 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
-
- return r;
}
-/** \ingroup asyncio
+/** \ingroup libusb_asyncio
* Allocate a libusb 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
* use it on a non-isochronous endpoint. If you do this, ensure that at time
* of submission, num_iso_packets is 0 and that type is set appropriately.
*
- * \param iso_packets number of isochronous packet descriptors to allocate
+ * \param iso_packets number of isochronous packet descriptors to allocate. Must be non-negative.
* \returns a newly allocated transfer, or NULL on error
*/
DEFAULT_VISIBILITY
struct libusb_transfer * LIBUSB_CALL libusb_alloc_transfer(
int iso_packets)
{
+ size_t priv_size;
+ size_t alloc_size;
+ unsigned char *ptr;
+ struct usbi_transfer *itransfer;
struct libusb_transfer *transfer;
- size_t os_alloc_size = usbi_backend->transfer_priv_size
- + (usbi_backend->add_iso_packet_size * iso_packets);
- size_t alloc_size = sizeof(struct usbi_transfer)
+
+ assert(iso_packets >= 0);
+ if (iso_packets < 0)
+ return NULL;
+
+ priv_size = PTR_ALIGN(usbi_backend.transfer_priv_size);
+ alloc_size = priv_size
+ + sizeof(struct usbi_transfer)
+ sizeof(struct libusb_transfer)
- + (sizeof(struct libusb_iso_packet_descriptor) * iso_packets)
- + os_alloc_size;
- struct usbi_transfer *itransfer = calloc(1, alloc_size);
- if (!itransfer)
+ + (sizeof(struct libusb_iso_packet_descriptor) * (size_t)iso_packets);
+ ptr = calloc(1, alloc_size);
+ if (!ptr)
return NULL;
+ itransfer = (struct usbi_transfer *)(ptr + priv_size);
itransfer->num_iso_packets = iso_packets;
- usbi_mutex_init(&itransfer->lock, NULL);
+ itransfer->priv = ptr;
+ usbi_mutex_init(&itransfer->lock);
transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
- usbi_dbg("transfer %p", transfer);
return transfer;
}
-/** \ingroup asyncio
+/** \ingroup libusb_asyncio
* Free a transfer structure. This should be called for all transfers
* allocated with libusb_alloc_transfer().
*
void API_EXPORTED libusb_free_transfer(struct libusb_transfer *transfer)
{
struct usbi_transfer *itransfer;
+ size_t priv_size;
+ unsigned char *ptr;
+
if (!transfer)
return;
- usbi_dbg("transfer %p", transfer);
- if (transfer->flags & LIBUSB_TRANSFER_FREE_BUFFER && transfer->buffer)
+ usbi_dbg(TRANSFER_CTX(transfer), "transfer %p", transfer);
+ if (transfer->flags & LIBUSB_TRANSFER_FREE_BUFFER)
free(transfer->buffer);
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;
+ priv_size = PTR_ALIGN(usbi_backend.transfer_priv_size);
+ ptr = (unsigned char *)itransfer - priv_size;
+ assert(ptr == itransfer->priv);
+ free(ptr);
}
-/* iterates through the flying transfers, and rearms the timerfd based on the
+/* iterates through the flying transfers, and rearms the timer 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.
+ * returns 0 on success or a LIBUSB_ERROR code on failure.
*/
-static int arm_timerfd_for_next_timeout(struct libusb_context *ctx)
+#ifdef HAVE_OS_TIMER
+static int arm_timer_for_next_timeout(struct libusb_context *ctx)
{
- struct usbi_transfer *transfer;
+ struct usbi_transfer *itransfer;
+
+ if (!usbi_using_timer(ctx))
+ return 0;
- list_for_each_entry(transfer, &ctx->flying_transfers, list, struct usbi_transfer) {
- struct timeval *cur_tv = &transfer->timeout;
+ for_each_transfer(ctx, itransfer) {
+ struct timespec *cur_ts = &itransfer->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;
+ if (!TIMESPEC_IS_SET(cur_ts))
+ break;
+
+ /* act on first transfer that has not already been handled */
+ if (!(itransfer->timeout_flags & (USBI_TRANSFER_TIMEOUT_HANDLED | USBI_TRANSFER_OS_HANDLES_TIMEOUT))) {
+ usbi_dbg(ctx, "next timeout originally %ums", USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer)->timeout);
+ return usbi_arm_timer(&ctx->timer, cur_ts);
}
}
-disarm:
- return disarm_timerfd(ctx);
+ usbi_dbg(ctx, "no timeouts, disarming timer");
+ return usbi_disarm_timer(&ctx->timer);
}
#else
-static int arm_timerfd_for_next_timeout(struct libusb_context *ctx)
+static inline int arm_timer_for_next_timeout(struct libusb_context *ctx)
{
- (void)ctx;
+ UNUSED(ctx);
return 0;
}
#endif
-/** \ingroup asyncio
+/* 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 *itransfer)
+{
+ struct usbi_transfer *cur;
+ struct timespec *timeout = &itransfer->timeout;
+ struct libusb_context *ctx = ITRANSFER_CTX(itransfer);
+ int r = 0;
+ int first = 1;
+
+ calculate_timeout(itransfer);
+
+ /* if we have no other flying transfers, start the list with this one */
+ if (list_empty(&ctx->flying_transfers)) {
+ list_add(&itransfer->list, &ctx->flying_transfers);
+ goto out;
+ }
+
+ /* if we have infinite timeout, append to end of list */
+ if (!TIMESPEC_IS_SET(timeout)) {
+ list_add_tail(&itransfer->list, &ctx->flying_transfers);
+ /* first is irrelevant in this case */
+ goto out;
+ }
+
+ /* otherwise, find appropriate place in list */
+ for_each_transfer(ctx, cur) {
+ /* find first timeout that occurs after the transfer in question */
+ struct timespec *cur_ts = &cur->timeout;
+
+ if (!TIMESPEC_IS_SET(cur_ts) || TIMESPEC_CMP(cur_ts, timeout, >)) {
+ list_add_tail(&itransfer->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(&itransfer->list, &ctx->flying_transfers);
+out:
+#ifdef HAVE_OS_TIMER
+ if (first && usbi_using_timer(ctx) && TIMESPEC_IS_SET(timeout)) {
+ /* if this transfer has the lowest timeout of all active transfers,
+ * rearm the timer with this transfer's timeout */
+ usbi_dbg(ctx, "arm timer for timeout in %ums (first in line)",
+ USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer)->timeout);
+ r = usbi_arm_timer(&ctx->timer, timeout);
+ }
+#else
+ UNUSED(first);
+#endif
+
+ if (r)
+ list_del(&itransfer->list);
+
+ 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 *itransfer)
+{
+ struct libusb_context *ctx = ITRANSFER_CTX(itransfer);
+ int rearm_timer;
+ int r = 0;
+
+ usbi_mutex_lock(&ctx->flying_transfers_lock);
+ rearm_timer = (TIMESPEC_IS_SET(&itransfer->timeout) &&
+ list_first_entry(&ctx->flying_transfers, struct usbi_transfer, list) == itransfer);
+ list_del(&itransfer->list);
+ if (rearm_timer)
+ r = arm_timer_for_next_timeout(ctx);
+ usbi_mutex_unlock(&ctx->flying_transfers_lock);
+
+ return r;
+}
+
+/** \ingroup libusb_asyncio
* Submit a transfer. This function will fire off the USB transfer and then
* return immediately.
*
* \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 LIBUSB_ERROR_INVALID_PARAM if the transfer size is larger than
+ * the operating system and/or hardware can support (see \ref asynclimits)
* \returns another LIBUSB_ERROR code on other failure
*/
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);
+ struct libusb_context *ctx = TRANSFER_CTX(transfer);
int r;
- usbi_dbg("transfer %p", transfer);
+ usbi_dbg(ctx, "transfer %p", transfer);
+
+ /*
+ * Important note on locking, this function takes / releases locks
+ * in the following order:
+ * take flying_transfers_lock
+ * take itransfer->lock
+ * clear transfer
+ * add to flying_transfers list
+ * release flying_transfers_lock
+ * submit transfer
+ * release itransfer->lock
+ * if submit failed:
+ * take flying_transfers_lock
+ * remove from flying_transfers list
+ * release flying_transfers_lock
+ *
+ * Note that it takes locks in the order a-b and then releases them
+ * in the same order a-b. This is somewhat unusual but not wrong,
+ * release order is not important as long as *all* locks are released
+ * before re-acquiring any locks.
+ *
+ * This means that the ordering of first releasing itransfer->lock
+ * and then re-acquiring the flying_transfers_list on error is
+ * important and must not be changed!
+ *
+ * This is done this way because when we take both locks we must always
+ * take flying_transfers_lock first to avoid ab-ba style deadlocks with
+ * the timeout handling and usbi_handle_disconnect paths.
+ *
+ * And we cannot release itransfer->lock before the submission is
+ * complete otherwise timeout handling for transfers with short
+ * timeouts may run before submission.
+ */
usbi_mutex_lock(&ctx->flying_transfers_lock);
usbi_mutex_lock(&itransfer->lock);
- if (itransfer->flags & USBI_TRANSFER_IN_FLIGHT) {
- r = LIBUSB_ERROR_BUSY;
- goto out;
+ if (itransfer->state_flags & USBI_TRANSFER_IN_FLIGHT) {
+ usbi_mutex_unlock(&ctx->flying_transfers_lock);
+ usbi_mutex_unlock(&itransfer->lock);
+ return LIBUSB_ERROR_BUSY;
}
itransfer->transferred = 0;
- itransfer->flags = 0;
- r = calculate_timeout(itransfer);
- if (r < 0) {
- r = LIBUSB_ERROR_OTHER;
- goto out;
+ itransfer->state_flags = 0;
+ itransfer->timeout_flags = 0;
+ r = add_to_flying_list(itransfer);
+ if (r) {
+ usbi_mutex_unlock(&ctx->flying_transfers_lock);
+ usbi_mutex_unlock(&itransfer->lock);
+ return r;
}
+ /*
+ * We must release the flying transfers lock here, because with
+ * some backends the submit_transfer method is synchroneous.
+ */
+ usbi_mutex_unlock(&ctx->flying_transfers_lock);
- r = add_to_flying_list(itransfer);
+ r = usbi_backend.submit_transfer(itransfer);
if (r == LIBUSB_SUCCESS) {
- r = usbi_backend->submit_transfer(itransfer);
- }
- if (r != LIBUSB_SUCCESS) {
- list_del(&itransfer->list);
- arm_timerfd_for_next_timeout(ctx);
- } else {
- itransfer->flags |= USBI_TRANSFER_IN_FLIGHT;
+ itransfer->state_flags |= USBI_TRANSFER_IN_FLIGHT;
/* keep a reference to this device */
libusb_ref_device(transfer->dev_handle->dev);
}
-out:
usbi_mutex_unlock(&itransfer->lock);
- usbi_mutex_unlock(&ctx->flying_transfers_lock);
+
+ if (r != LIBUSB_SUCCESS)
+ remove_from_flying_list(itransfer);
+
return r;
}
-/** \ingroup asyncio
+/** \ingroup libusb_asyncio
* Asynchronously cancel a previously submitted transfer.
* This function returns immediately, but this does not indicate cancellation
* is complete. Your callback function will be invoked at some later time
{
struct usbi_transfer *itransfer =
LIBUSB_TRANSFER_TO_USBI_TRANSFER(transfer);
+ struct libusb_context *ctx = ITRANSFER_CTX(itransfer);
int r;
- usbi_dbg("transfer %p", transfer );
+ usbi_dbg(ctx, "transfer %p", transfer );
usbi_mutex_lock(&itransfer->lock);
- if (!(itransfer->flags & USBI_TRANSFER_IN_FLIGHT)
- || (itransfer->flags & USBI_TRANSFER_CANCELLING)) {
+ if (!(itransfer->state_flags & USBI_TRANSFER_IN_FLIGHT)
+ || (itransfer->state_flags & USBI_TRANSFER_CANCELLING)) {
r = LIBUSB_ERROR_NOT_FOUND;
goto out;
}
- r = usbi_backend->cancel_transfer(itransfer);
+ r = usbi_backend.cancel_transfer(itransfer);
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);
+ usbi_err(ctx, "cancel transfer failed error %d", r);
else
- usbi_dbg("cancel transfer failed error %d", r);
+ usbi_dbg(ctx, "cancel transfer failed error %d", r);
if (r == LIBUSB_ERROR_NO_DEVICE)
- itransfer->flags |= USBI_TRANSFER_DEVICE_DISAPPEARED;
+ itransfer->state_flags |= USBI_TRANSFER_DEVICE_DISAPPEARED;
}
- itransfer->flags |= USBI_TRANSFER_CANCELLING;
+ itransfer->state_flags |= USBI_TRANSFER_CANCELLING;
out:
usbi_mutex_unlock(&itransfer->lock);
return r;
}
-/** \ingroup asyncio
+/** \ingroup libusb_asyncio
* Set a transfers bulk stream id. Note users are advised to use
* libusb_fill_bulk_stream_transfer() instead of calling this function
* directly.
itransfer->stream_id = stream_id;
}
-/** \ingroup asyncio
+/** \ingroup libusb_asyncio
* Get a transfers bulk stream id.
*
* Since version 1.0.19, \ref LIBUSB_API_VERSION >= 0x01000103
{
struct libusb_transfer *transfer =
USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
- struct libusb_context *ctx = TRANSFER_CTX(transfer);
- struct libusb_device_handle *handle = transfer->dev_handle;
+ struct libusb_device_handle *dev_handle = transfer->dev_handle;
+ struct libusb_context *ctx = ITRANSFER_CTX(itransfer);
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. */
+ int r;
- usbi_mutex_lock(&ctx->flying_transfers_lock);
- list_del(&itransfer->list);
- 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;
+ r = remove_from_flying_list(itransfer);
+ if (r < 0)
+ usbi_err(ctx, "failed to set timer for next timeout");
usbi_mutex_lock(&itransfer->lock);
- itransfer->flags &= ~USBI_TRANSFER_IN_FLIGHT;
+ itransfer->state_flags &= ~USBI_TRANSFER_IN_FLIGHT;
usbi_mutex_unlock(&itransfer->lock);
if (status == LIBUSB_TRANSFER_COMPLETED
if (transfer->type == LIBUSB_TRANSFER_TYPE_CONTROL)
rqlen -= LIBUSB_CONTROL_SETUP_SIZE;
if (rqlen != itransfer->transferred) {
- usbi_dbg("interpreting short transfer as error");
+ usbi_dbg(ctx, "interpreting short transfer as error");
status = LIBUSB_TRANSFER_ERROR;
}
}
flags = transfer->flags;
transfer->status = status;
transfer->actual_length = itransfer->transferred;
- usbi_dbg("transfer %p has callback %p", transfer, transfer->callback);
+ usbi_dbg(ctx, "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);
- libusb_unref_device(handle->dev);
- return 0;
+ libusb_unref_device(dev_handle->dev);
+ return r;
}
/* Similar to usbi_handle_transfer_completion() but exclusively for transfers
* 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)
+int usbi_handle_transfer_cancellation(struct usbi_transfer *itransfer)
{
+ struct libusb_context *ctx = ITRANSFER_CTX(itransfer);
+ uint8_t timed_out;
+
+ usbi_mutex_lock(&ctx->flying_transfers_lock);
+ timed_out = itransfer->timeout_flags & USBI_TRANSFER_TIMED_OUT;
+ usbi_mutex_unlock(&ctx->flying_transfers_lock);
+
/* 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");
- return usbi_handle_transfer_completion(transfer, LIBUSB_TRANSFER_TIMED_OUT);
+ if (timed_out) {
+ usbi_dbg(ctx, "detected timeout cancellation");
+ return usbi_handle_transfer_completion(itransfer, LIBUSB_TRANSFER_TIMED_OUT);
}
/* otherwise its a normal async cancel */
- return usbi_handle_transfer_completion(transfer, LIBUSB_TRANSFER_CANCELLED);
+ return usbi_handle_transfer_completion(itransfer, 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)
+void usbi_signal_transfer_completion(struct usbi_transfer *itransfer)
{
- struct libusb_context *ctx = ITRANSFER_CTX(transfer);
- int pending_events;
+ libusb_device_handle *dev_handle = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer)->dev_handle;
- 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);
+ if (dev_handle) {
+ struct libusb_context *ctx = HANDLE_CTX(dev_handle);
+ unsigned int event_flags;
+
+ usbi_mutex_lock(&ctx->event_data_lock);
+ event_flags = ctx->event_flags;
+ ctx->event_flags |= USBI_EVENT_TRANSFER_COMPLETED;
+ list_add_tail(&itransfer->completed_list, &ctx->completed_transfers);
+ if (!event_flags)
+ usbi_signal_event(&ctx->event);
+ usbi_mutex_unlock(&ctx->event_data_lock);
+ }
}
-/** \ingroup poll
+/** \ingroup libusb_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)
- * \ref mtasync
+ * \ref libusb_mtasync
*/
int API_EXPORTED libusb_try_lock_events(libusb_context *ctx)
{
int r;
unsigned int ru;
- USBI_GET_CONTEXT(ctx);
+
+ ctx = usbi_get_context(ctx);
/* is someone else waiting to close a device? if so, don't let this thread
* start event handling */
ru = ctx->device_close;
usbi_mutex_unlock(&ctx->event_data_lock);
if (ru) {
- usbi_dbg("someone else is closing a device");
+ usbi_dbg(ctx, "someone else is closing a device");
return 1;
}
r = usbi_mutex_trylock(&ctx->events_lock);
- if (r)
+ if (!r)
return 1;
ctx->event_handler_active = 1;
return 0;
}
-/** \ingroup poll
+/** \ingroup libusb_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.
* as soon as possible.
*
* \param ctx the context to operate on, or NULL for the default context
- * \ref mtasync
+ * \ref libusb_mtasync
*/
void API_EXPORTED libusb_lock_events(libusb_context *ctx)
{
- USBI_GET_CONTEXT(ctx);
+ ctx = usbi_get_context(ctx);
usbi_mutex_lock(&ctx->events_lock);
ctx->event_handler_active = 1;
}
-/** \ingroup poll
+/** \ingroup libusb_poll
* Release the lock previously acquired with libusb_try_lock_events() or
* libusb_lock_events(). Releasing this lock will wake up any threads blocked
* on libusb_wait_for_event().
*
* \param ctx the context to operate on, or NULL for the default context
- * \ref mtasync
+ * \ref libusb_mtasync
*/
void API_EXPORTED libusb_unlock_events(libusb_context *ctx)
{
- USBI_GET_CONTEXT(ctx);
+ ctx = usbi_get_context(ctx);
ctx->event_handler_active = 0;
usbi_mutex_unlock(&ctx->events_lock);
usbi_mutex_unlock(&ctx->event_waiters_lock);
}
-/** \ingroup poll
+/** \ingroup libusb_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
* this is the case.
*
* If this function instructs your thread to give up the events lock, you
- * should just continue the usual logic that is documented in \ref mtasync.
+ * should just continue the usual logic that is documented in \ref libusb_mtasync.
* On the next iteration, your thread will fail to obtain the events lock,
* and will hence become an event waiter.
*
int API_EXPORTED libusb_event_handling_ok(libusb_context *ctx)
{
unsigned int r;
- USBI_GET_CONTEXT(ctx);
+
+ ctx = usbi_get_context(ctx);
/* is someone else waiting to close a device? if so, don't let this thread
* continue event handling */
r = ctx->device_close;
usbi_mutex_unlock(&ctx->event_data_lock);
if (r) {
- usbi_dbg("someone else is closing a device");
+ usbi_dbg(ctx, "someone else is closing a device");
return 0;
}
}
-/** \ingroup poll
+/** \ingroup libusb_poll
* Determine if an active thread is handling events (i.e. if anyone is holding
* the event handling lock).
*
* \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
- * \ref mtasync
+ * \ref libusb_mtasync
*/
int API_EXPORTED libusb_event_handler_active(libusb_context *ctx)
{
unsigned int r;
- USBI_GET_CONTEXT(ctx);
+
+ ctx = usbi_get_context(ctx);
/* is someone else waiting to close a device? if so, don't let this thread
* start event handling -- indicate that event handling is happening */
r = ctx->device_close;
usbi_mutex_unlock(&ctx->event_data_lock);
if (r) {
- usbi_dbg("someone else is closing a device");
+ usbi_dbg(ctx, "someone else is closing a device");
return 1;
}
return ctx->event_handler_active;
}
-/** \ingroup poll
+/** \ingroup libusb_poll
+ * Interrupt any active thread that is handling events. This is mainly useful
+ * for interrupting a dedicated event handling thread when an application
+ * wishes to call libusb_exit().
+ *
+ * Since version 1.0.21, \ref LIBUSB_API_VERSION >= 0x01000105
+ *
+ * \param ctx the context to operate on, or NULL for the default context
+ * \ref libusb_mtasync
+ */
+void API_EXPORTED libusb_interrupt_event_handler(libusb_context *ctx)
+{
+ unsigned int event_flags;
+
+ usbi_dbg(ctx, " ");
+
+ ctx = usbi_get_context(ctx);
+ usbi_mutex_lock(&ctx->event_data_lock);
+
+ event_flags = ctx->event_flags;
+ ctx->event_flags |= USBI_EVENT_USER_INTERRUPT;
+ if (!event_flags)
+ usbi_signal_event(&ctx->event);
+
+ usbi_mutex_unlock(&ctx->event_data_lock);
+}
+
+/** \ingroup libusb_poll
* Acquire the event waiters lock. This lock is designed to be obtained under
* the situation where you want to be aware when events are completed, but
* some other thread is event handling so calling libusb_handle_events() is not
*
* You only need to use this lock if you are developing an application
* which calls poll() or select() on libusb's file descriptors directly,
- * <b>and</b> may potentially be handling events from 2 threads simultaenously.
+ * <b>and</b> may potentially be handling events from 2 threads simultaneously.
* If you stick to libusb'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
- * \ref mtasync
+ * \ref libusb_mtasync
*/
void API_EXPORTED libusb_lock_event_waiters(libusb_context *ctx)
{
- USBI_GET_CONTEXT(ctx);
+ ctx = usbi_get_context(ctx);
usbi_mutex_lock(&ctx->event_waiters_lock);
}
-/** \ingroup poll
+/** \ingroup libusb_poll
* Release the event waiters lock.
* \param ctx the context to operate on, or NULL for the default context
- * \ref mtasync
+ * \ref libusb_mtasync
*/
void API_EXPORTED libusb_unlock_event_waiters(libusb_context *ctx)
{
- USBI_GET_CONTEXT(ctx);
+ ctx = usbi_get_context(ctx);
usbi_mutex_unlock(&ctx->event_waiters_lock);
}
-/** \ingroup poll
+/** \ingroup libusb_poll
* Wait for another thread to signal completion of an event. Must be called
* with the event waiters lock held, see libusb_lock_event_waiters().
*
* indicates unlimited timeout.
* \returns 0 after a transfer completes or another thread stops event handling
* \returns 1 if the timeout expired
- * \ref mtasync
+ * \returns LIBUSB_ERROR_INVALID_PARAM if timeval is invalid
+ * \ref libusb_mtasync
*/
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) {
+ ctx = usbi_get_context(ctx);
+ if (!tv) {
usbi_cond_wait(&ctx->event_waiters_cond, &ctx->event_waiters_lock);
return 0;
}
- 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 += tv->tv_sec;
- timeout.tv_nsec += tv->tv_usec * 1000;
- while (timeout.tv_nsec >= 1000000000) {
- timeout.tv_nsec -= 1000000000;
- timeout.tv_sec++;
- }
+ if (!TIMEVAL_IS_VALID(tv))
+ return LIBUSB_ERROR_INVALID_PARAM;
r = usbi_cond_timedwait(&ctx->event_waiters_cond,
- &ctx->event_waiters_lock, &timeout);
- return (r == ETIMEDOUT);
+ &ctx->event_waiters_lock, tv);
+ if (r < 0)
+ return r == LIBUSB_ERROR_TIMEOUT;
+
+ return 0;
}
static void handle_timeout(struct usbi_transfer *itransfer)
USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
int r;
- itransfer->flags |= USBI_TRANSFER_TIMED_OUT;
+ itransfer->timeout_flags |= USBI_TRANSFER_TIMEOUT_HANDLED;
r = libusb_cancel_transfer(transfer);
- if (r < 0)
+ if (r == LIBUSB_SUCCESS)
+ itransfer->timeout_flags |= USBI_TRANSFER_TIMED_OUT;
+ else
usbi_warn(TRANSFER_CTX(transfer),
- "async cancel failed %d errno=%d", r, errno);
+ "async cancel failed %d", r);
}
-static int handle_timeouts_locked(struct libusb_context *ctx)
+static void handle_timeouts_locked(struct libusb_context *ctx)
{
- int r;
- struct timespec systime_ts;
- struct timeval systime;
- struct usbi_transfer *transfer;
+ struct timespec systime;
+ struct usbi_transfer *itransfer;
if (list_empty(&ctx->flying_transfers))
- return 0;
+ return;
/* get current time */
- r = usbi_backend->clock_gettime(USBI_CLOCK_MONOTONIC, &systime_ts);
- if (r < 0)
- return r;
-
- TIMESPEC_TO_TIMEVAL(&systime, &systime_ts);
+ usbi_get_monotonic_time(&systime);
/* iterate through flying transfers list, finding all transfers that
* have expired timeouts */
- list_for_each_entry(transfer, &ctx->flying_transfers, list, struct usbi_transfer) {
- struct timeval *cur_tv = &transfer->timeout;
+ for_each_transfer(ctx, itransfer) {
+ struct timespec *cur_ts = &itransfer->timeout;
/* if we've reached transfers of infinite timeout, we're all done */
- if (!timerisset(cur_tv))
- return 0;
+ if (!TIMESPEC_IS_SET(cur_ts))
+ return;
/* ignore timeouts we've already handled */
- if (transfer->flags & (USBI_TRANSFER_TIMED_OUT | USBI_TRANSFER_OS_HANDLES_TIMEOUT))
+ if (itransfer->timeout_flags & (USBI_TRANSFER_TIMEOUT_HANDLED | 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))
- return 0;
+ if (TIMESPEC_CMP(cur_ts, &systime, >))
+ return;
/* otherwise, we've got an expired timeout to handle */
- handle_timeout(transfer);
+ handle_timeout(itransfer);
}
- return 0;
}
-static int handle_timeouts(struct libusb_context *ctx)
+static void handle_timeouts(struct libusb_context *ctx)
{
- int r;
- USBI_GET_CONTEXT(ctx);
+ ctx = usbi_get_context(ctx);
usbi_mutex_lock(&ctx->flying_transfers_lock);
- r = handle_timeouts_locked(ctx);
+ handle_timeouts_locked(ctx);
usbi_mutex_unlock(&ctx->flying_transfers_lock);
+}
+
+static int handle_event_trigger(struct libusb_context *ctx)
+{
+ struct list_head hotplug_msgs;
+ int hotplug_event = 0;
+ int r = 0;
+
+ usbi_dbg(ctx, "event triggered");
+
+ list_init(&hotplug_msgs);
+
+ /* take the the event data lock while processing events */
+ usbi_mutex_lock(&ctx->event_data_lock);
+
+ /* check if someone modified the event sources */
+ if (ctx->event_flags & USBI_EVENT_EVENT_SOURCES_MODIFIED)
+ usbi_dbg(ctx, "someone updated the event sources");
+
+ if (ctx->event_flags & USBI_EVENT_USER_INTERRUPT) {
+ usbi_dbg(ctx, "someone purposefully interrupted");
+ ctx->event_flags &= ~USBI_EVENT_USER_INTERRUPT;
+ }
+
+ if (ctx->event_flags & USBI_EVENT_HOTPLUG_CB_DEREGISTERED) {
+ usbi_dbg(ctx, "someone unregistered a hotplug cb");
+ ctx->event_flags &= ~USBI_EVENT_HOTPLUG_CB_DEREGISTERED;
+ hotplug_event = 1;
+ }
+
+ /* check if someone is closing a device */
+ if (ctx->event_flags & USBI_EVENT_DEVICE_CLOSE)
+ usbi_dbg(ctx, "someone is closing a device");
+
+ /* check for any pending hotplug messages */
+ if (ctx->event_flags & USBI_EVENT_HOTPLUG_MSG_PENDING) {
+ usbi_dbg(ctx, "hotplug message received");
+ ctx->event_flags &= ~USBI_EVENT_HOTPLUG_MSG_PENDING;
+ hotplug_event = 1;
+ assert(!list_empty(&ctx->hotplug_msgs));
+ list_cut(&hotplug_msgs, &ctx->hotplug_msgs);
+ }
+
+ /* complete any pending transfers */
+ if (ctx->event_flags & USBI_EVENT_TRANSFER_COMPLETED) {
+ struct usbi_transfer *itransfer, *tmp;
+ struct list_head completed_transfers;
+
+ assert(!list_empty(&ctx->completed_transfers));
+ list_cut(&completed_transfers, &ctx->completed_transfers);
+ usbi_mutex_unlock(&ctx->event_data_lock);
+
+ __for_each_completed_transfer_safe(&completed_transfers, itransfer, tmp) {
+ list_del(&itransfer->completed_list);
+ r = usbi_backend.handle_transfer_completion(itransfer);
+ if (r) {
+ usbi_err(ctx, "backend handle_transfer_completion failed with error %d", r);
+ break;
+ }
+ }
+
+ usbi_mutex_lock(&ctx->event_data_lock);
+ if (!list_empty(&completed_transfers)) {
+ /* an error occurred, put the remaining transfers back on the list */
+ list_splice_front(&completed_transfers, &ctx->completed_transfers);
+ } else if (list_empty(&ctx->completed_transfers)) {
+ ctx->event_flags &= ~USBI_EVENT_TRANSFER_COMPLETED;
+ }
+ }
+
+ /* if no further pending events, clear the event */
+ if (!ctx->event_flags)
+ usbi_clear_event(&ctx->event);
+
+ usbi_mutex_unlock(&ctx->event_data_lock);
+
+ /* process the hotplug events, if any */
+ if (hotplug_event)
+ usbi_hotplug_process(ctx, &hotplug_msgs);
+
return r;
}
-#ifdef USBI_TIMERFD_AVAILABLE
-static int handle_timerfd_trigger(struct libusb_context *ctx)
+#ifdef HAVE_OS_TIMER
+static int handle_timer_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;
+ handle_timeouts_locked(ctx);
- /* arm for next timeout*/
- r = arm_timerfd_for_next_timeout(ctx);
+ /* arm for next timeout */
+ r = arm_timer_for_next_timeout(ctx);
-out:
usbi_mutex_unlock(&ctx->flying_transfers_lock);
+
return r;
}
#endif
* doing the same thing. */
static int handle_events(struct libusb_context *ctx, struct timeval *tv)
{
- int r;
- struct usbi_pollfd *ipollfd;
- POLL_NFDS_TYPE nfds = 0;
- POLL_NFDS_TYPE internal_nfds;
- struct pollfd *fds = NULL;
- int i = -1;
- int timeout_ms;
- int special_event;
-
- /* 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;
+ struct usbi_reported_events reported_events;
+ int r, timeout_ms;
- /* 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");
+ /* prevent attempts to recursively handle events (e.g. calling into
+ * libusb_handle_events() from within a hotplug or transfer callback) */
+ if (usbi_handling_events(ctx))
+ return LIBUSB_ERROR_BUSY;
- if (ctx->pollfds) {
- free(ctx->pollfds);
- ctx->pollfds = NULL;
- }
+ /* only reallocate the event source data when the list of event sources has
+ * been modified since the last handle_events(), otherwise reuse them to
+ * save the additional overhead */
+ usbi_mutex_lock(&ctx->event_data_lock);
+ if (ctx->event_flags & USBI_EVENT_EVENT_SOURCES_MODIFIED) {
+ usbi_dbg(ctx, "event sources modified, reallocating event data");
- /* sanity check - it is invalid for a context to have fewer than the
- * required internal fds (memory corruption?) */
- assert(ctx->pollfds_cnt >= internal_nfds);
+ /* free anything removed since we last ran */
+ cleanup_removed_event_sources(ctx);
- ctx->pollfds = calloc(ctx->pollfds_cnt, sizeof(*ctx->pollfds));
- if (!ctx->pollfds) {
+ r = usbi_alloc_event_data(ctx);
+ if (r) {
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;
+ return r;
}
/* reset the flag now that we have the updated list */
- ctx->pollfds_modified = 0;
+ ctx->event_flags &= ~USBI_EVENT_EVENT_SOURCES_MODIFIED;
- /* 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);
+ /* if no further pending events, clear the event so that we do
+ * not immediately return from the wait function */
+ if (!ctx->event_flags)
+ usbi_clear_event(&ctx->event);
}
- fds = ctx->pollfds;
- nfds = ctx->pollfds_cnt;
usbi_mutex_unlock(&ctx->event_data_lock);
timeout_ms = (int)(tv->tv_sec * 1000) + (tv->tv_usec / 1000);
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)
- return handle_timeouts(ctx);
- else if (r == -1 && errno == EINTR)
- return LIBUSB_ERROR_INTERRUPTED;
- else if (r < 0) {
- usbi_err(ctx, "poll failed %d err=%d\n", r, errno);
- return LIBUSB_ERROR_IO;
- }
-
- special_event = 0;
-
- /* fds[0] is always the event pipe */
- if (fds[0].revents) {
- 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");
+ reported_events.event_bits = 0;
- /* 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 no further pending events, clear the event pipe */
- if (!usbi_pending_events(ctx))
- usbi_clear_event(ctx);
-
- usbi_mutex_unlock(&ctx->event_data_lock);
+ usbi_start_event_handling(ctx);
- /* 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);
+ r = usbi_wait_for_events(ctx, &reported_events, timeout_ms);
+ if (r != LIBUSB_SUCCESS) {
+ if (r == LIBUSB_ERROR_TIMEOUT) {
+ handle_timeouts(ctx);
+ r = LIBUSB_SUCCESS;
}
+ goto done;
+ }
- if (ret) {
+ if (reported_events.event_triggered) {
+ r = handle_event_trigger(ctx);
+ if (r) {
/* return error code */
- r = ret;
- goto handled;
+ goto done;
}
-
- if (0 == --r)
- goto handled;
}
-#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");
- special_event = 1;
-
- ret = handle_timerfd_trigger(ctx);
- if (ret < 0) {
+#ifdef HAVE_OS_TIMER
+ if (reported_events.timer_triggered) {
+ r = handle_timer_trigger(ctx);
+ if (r) {
/* return error code */
- r = ret;
- goto handled;
+ goto done;
}
-
- if (0 == --r)
- goto handled;
}
#endif
- r = usbi_backend->handle_events(ctx, fds + internal_nfds, nfds - internal_nfds, r);
+ if (!reported_events.num_ready)
+ goto done;
+
+ r = usbi_backend.handle_events(ctx, reported_events.event_data,
+ reported_events.event_data_count, reported_events.num_ready);
if (r)
usbi_err(ctx, "backend handle_events failed with error %d", r);
-handled:
- if (r == 0 && special_event) {
- timeout_ms = 0;
- goto redo_poll;
- }
-
+done:
+ usbi_end_event_handling(ctx);
return r;
}
return 0;
}
-/** \ingroup poll
+/** \ingroup libusb_poll
* Handle any pending events.
*
* libusb determines "pending events" by checking if any timeouts have expired
* \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
+ * \returns 0 on success
+ * \returns LIBUSB_ERROR_INVALID_PARAM if timeval is invalid
+ * \returns another LIBUSB_ERROR code on other failure
+ * \ref libusb_mtasync
*/
int API_EXPORTED libusb_handle_events_timeout_completed(libusb_context *ctx,
struct timeval *tv, int *completed)
int r;
struct timeval poll_timeout;
- USBI_GET_CONTEXT(ctx);
+ if (!TIMEVAL_IS_VALID(tv))
+ return LIBUSB_ERROR_INVALID_PARAM;
+
+ ctx = usbi_get_context(ctx);
r = get_next_timeout(ctx, tv, &poll_timeout);
if (r) {
/* timeout already expired */
- return handle_timeouts(ctx);
+ handle_timeouts(ctx);
+ return 0;
}
retry:
if (libusb_try_lock_events(ctx) == 0) {
if (completed == NULL || !*completed) {
/* we obtained the event lock: do our own event handling */
- usbi_dbg("doing our own event handling");
+ usbi_dbg(ctx, "doing our own event handling");
r = handle_events(ctx, &poll_timeout);
}
libusb_unlock_events(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. */
libusb_unlock_event_waiters(ctx);
- usbi_dbg("event handler was active but went away, retrying");
+ usbi_dbg(ctx, "event handler was active but went away, retrying");
goto retry;
}
- usbi_dbg("another thread is doing event handling");
+ usbi_dbg(ctx, "another thread is doing event handling");
r = libusb_wait_for_event(ctx, &poll_timeout);
already_done:
if (r < 0)
return r;
else if (r == 1)
- return handle_timeouts(ctx);
- else
- return 0;
+ handle_timeouts(ctx);
+ return 0;
}
-/** \ingroup poll
+/** \ingroup libusb_poll
* Handle any pending events
*
* Like libusb_handle_events_timeout_completed(), but without the completed
return libusb_handle_events_timeout_completed(ctx, tv, NULL);
}
-/** \ingroup poll
+/** \ingroup libusb_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
+ * hard-coded 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.
return libusb_handle_events_timeout_completed(ctx, &tv, NULL);
}
-/** \ingroup poll
+/** \ingroup libusb_poll
* Handle any pending events in blocking mode.
*
* Like libusb_handle_events(), with the addition of a 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
+ * \ref libusb_mtasync
*/
int API_EXPORTED libusb_handle_events_completed(libusb_context *ctx,
int *completed)
return libusb_handle_events_timeout_completed(ctx, &tv, completed);
}
-/** \ingroup poll
+/** \ingroup libusb_poll
* Handle any pending events by polling file descriptors, without checking if
* any other threads are already doing so. Must be called with the event lock
* held, see libusb_lock_events().
* \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
- * \returns 0 on success, or a LIBUSB_ERROR code on failure
- * \ref mtasync
+ * \returns 0 on success
+ * \returns LIBUSB_ERROR_INVALID_PARAM if timeval is invalid
+ * \returns another LIBUSB_ERROR code on other failure
+ * \ref libusb_mtasync
*/
int API_EXPORTED libusb_handle_events_locked(libusb_context *ctx,
struct timeval *tv)
int r;
struct timeval poll_timeout;
- USBI_GET_CONTEXT(ctx);
+ if (!TIMEVAL_IS_VALID(tv))
+ return LIBUSB_ERROR_INVALID_PARAM;
+
+ ctx = usbi_get_context(ctx);
r = get_next_timeout(ctx, tv, &poll_timeout);
if (r) {
/* timeout already expired */
- return handle_timeouts(ctx);
+ handle_timeouts(ctx);
+ return 0;
}
return handle_events(ctx, &poll_timeout);
}
-/** \ingroup poll
+/** \ingroup libusb_poll
* Determines whether your application must apply special timing considerations
* when monitoring libusb's file descriptors.
*
* This function is only useful for applications which retrieve and poll
- * libusb's file descriptors in their own main loop (\ref pollmain).
+ * libusb's file descriptors in their own main loop (\ref libusb_pollmain).
*
* Ordinarily, libusb's event handler needs to be called into at specific
* moments in time (in addition to times when there is activity on the file
* \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.
- * \ref pollmain "Polling libusb file descriptors for event handling"
+ * \ref libusb_pollmain "Polling libusb 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
+ ctx = usbi_get_context(ctx);
+ return usbi_using_timer(ctx);
}
-/** \ingroup poll
+/** \ingroup libusb_poll
* Determine the next internal timeout that libusb 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
int API_EXPORTED libusb_get_next_timeout(libusb_context *ctx,
struct timeval *tv)
{
- struct usbi_transfer *transfer;
- struct timespec cur_ts;
- struct timeval cur_tv;
- struct timeval *next_timeout;
- int r;
- int found = 0;
+ struct usbi_transfer *itransfer;
+ struct timespec systime;
+ struct timespec next_timeout = { 0, 0 };
- USBI_GET_CONTEXT(ctx);
- if (usbi_using_timerfd(ctx))
+ ctx = usbi_get_context(ctx);
+ if (usbi_using_timer(ctx))
return 0;
usbi_mutex_lock(&ctx->flying_transfers_lock);
if (list_empty(&ctx->flying_transfers)) {
usbi_mutex_unlock(&ctx->flying_transfers_lock);
- usbi_dbg("no URBs, no timeout!");
+ usbi_dbg(ctx, "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, struct usbi_transfer) {
- if (transfer->flags & (USBI_TRANSFER_TIMED_OUT | USBI_TRANSFER_OS_HANDLES_TIMEOUT))
+ for_each_transfer(ctx, itransfer) {
+ if (itransfer->timeout_flags & (USBI_TRANSFER_TIMEOUT_HANDLED | USBI_TRANSFER_OS_HANDLES_TIMEOUT))
continue;
- /* no timeout for this transfer? */
- if (!timerisset(&transfer->timeout))
- continue;
+ /* if we've reached transfers of infinite timeout, we're done looking */
+ if (!TIMESPEC_IS_SET(&itransfer->timeout))
+ break;
- found = 1;
+ next_timeout = itransfer->timeout;
break;
}
usbi_mutex_unlock(&ctx->flying_transfers_lock);
- if (!found) {
- usbi_dbg("no URB with timeout or all handled by OS; no timeout!");
+ if (!TIMESPEC_IS_SET(&next_timeout)) {
+ usbi_dbg(ctx, "no URB with timeout or all handled by OS; no timeout!");
return 0;
}
- next_timeout = &transfer->timeout;
+ usbi_get_monotonic_time(&systime);
- 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 0;
- }
- TIMESPEC_TO_TIMEVAL(&cur_tv, &cur_ts);
-
- if (!timercmp(&cur_tv, next_timeout, <)) {
- usbi_dbg("first timeout already expired");
+ if (!TIMESPEC_CMP(&systime, &next_timeout, <)) {
+ usbi_dbg(ctx, "first timeout already expired");
timerclear(tv);
} else {
- timersub(next_timeout, &cur_tv, tv);
- usbi_dbg("next timeout in %d.%06ds", tv->tv_sec, tv->tv_usec);
+ TIMESPEC_SUB(&next_timeout, &systime, &next_timeout);
+ TIMESPEC_TO_TIMEVAL(tv, &next_timeout);
+ usbi_dbg(ctx, "next timeout in %ld.%06lds", (long)tv->tv_sec, (long)tv->tv_usec);
}
return 1;
}
-/** \ingroup poll
+/** \ingroup libusb_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.
libusb_pollfd_added_cb added_cb, libusb_pollfd_removed_cb removed_cb,
void *user_data)
{
- USBI_GET_CONTEXT(ctx);
+#if !defined(PLATFORM_WINDOWS)
+ ctx = usbi_get_context(ctx);
ctx->fd_added_cb = added_cb;
ctx->fd_removed_cb = removed_cb;
ctx->fd_cb_user_data = user_data;
+#else
+ usbi_err(ctx, "external polling of libusb's internal event sources " \
+ "is not yet supported on Windows");
+ UNUSED(added_cb);
+ UNUSED(removed_cb);
+ UNUSED(user_data);
+#endif
}
/*
* 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.
+ * up the event source change. Callers of this function must hold the event_data_lock.
*/
-static void usbi_fd_notification(struct libusb_context *ctx)
+static void usbi_event_source_notification(struct libusb_context *ctx)
{
- int pending_events;
+ unsigned int event_flags;
/* 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);
+ event_flags = ctx->event_flags;
+ ctx->event_flags |= USBI_EVENT_EVENT_SOURCES_MODIFIED;
+ if (!event_flags)
+ usbi_signal_event(&ctx->event);
}
-/* 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.
+/* Add an event source to the list of event sources to be monitored.
+ * poll_events should be specified as a bitmask of events passed to poll(), e.g.
* POLLIN and/or POLLOUT. */
-int usbi_add_pollfd(struct libusb_context *ctx, int fd, short events)
+int usbi_add_event_source(struct libusb_context *ctx, usbi_os_handle_t os_handle, short poll_events)
{
- struct usbi_pollfd *ipollfd = malloc(sizeof(*ipollfd));
- if (!ipollfd)
+ struct usbi_event_source *ievent_source = malloc(sizeof(*ievent_source));
+
+ if (!ievent_source)
return LIBUSB_ERROR_NO_MEM;
- usbi_dbg("add fd %d events %d", fd, events);
- ipollfd->pollfd.fd = fd;
- ipollfd->pollfd.events = events;
+ usbi_dbg(ctx, "add " USBI_OS_HANDLE_FORMAT_STRING " events %d", os_handle, poll_events);
+ ievent_source->data.os_handle = os_handle;
+ ievent_source->data.poll_events = poll_events;
usbi_mutex_lock(&ctx->event_data_lock);
- list_add_tail(&ipollfd->list, &ctx->ipollfds);
- ctx->pollfds_cnt++;
- usbi_fd_notification(ctx);
+ list_add_tail(&ievent_source->list, &ctx->event_sources);
+ usbi_event_source_notification(ctx);
usbi_mutex_unlock(&ctx->event_data_lock);
+#if !defined(PLATFORM_WINDOWS)
if (ctx->fd_added_cb)
- ctx->fd_added_cb(fd, events, ctx->fd_cb_user_data);
+ ctx->fd_added_cb(os_handle, poll_events, ctx->fd_cb_user_data);
+#endif
+
return 0;
}
-/* Remove a file descriptor from the list of file descriptors to be polled. */
-void usbi_remove_pollfd(struct libusb_context *ctx, int fd)
+/* Remove an event source from the list of event sources to be monitored. */
+void usbi_remove_event_source(struct libusb_context *ctx, usbi_os_handle_t os_handle)
{
- struct usbi_pollfd *ipollfd;
+ struct usbi_event_source *ievent_source;
int found = 0;
- usbi_dbg("remove fd %d", fd);
+ usbi_dbg(ctx, "remove " USBI_OS_HANDLE_FORMAT_STRING, os_handle);
usbi_mutex_lock(&ctx->event_data_lock);
- list_for_each_entry(ipollfd, &ctx->ipollfds, list, struct usbi_pollfd)
- if (ipollfd->pollfd.fd == fd) {
+ for_each_event_source(ctx, ievent_source) {
+ if (ievent_source->data.os_handle == os_handle) {
found = 1;
break;
}
+ }
if (!found) {
- usbi_dbg("couldn't find fd %d to remove", fd);
+ usbi_dbg(ctx, "couldn't find " USBI_OS_HANDLE_FORMAT_STRING " to remove", os_handle);
usbi_mutex_unlock(&ctx->event_data_lock);
return;
}
- list_del(&ipollfd->list);
- ctx->pollfds_cnt--;
- usbi_fd_notification(ctx);
+ list_del(&ievent_source->list);
+ list_add_tail(&ievent_source->list, &ctx->removed_event_sources);
+ usbi_event_source_notification(ctx);
usbi_mutex_unlock(&ctx->event_data_lock);
- free(ipollfd);
+
+#if !defined(PLATFORM_WINDOWS)
if (ctx->fd_removed_cb)
- ctx->fd_removed_cb(fd, ctx->fd_cb_user_data);
+ ctx->fd_removed_cb(os_handle, ctx->fd_cb_user_data);
+#endif
}
-/** \ingroup poll
+/** \ingroup libusb_poll
* 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.
const struct libusb_pollfd ** LIBUSB_CALL libusb_get_pollfds(
libusb_context *ctx)
{
-#ifndef OS_WINDOWS
+#if !defined(PLATFORM_WINDOWS)
struct libusb_pollfd **ret = NULL;
- struct usbi_pollfd *ipollfd;
- size_t i = 0;
- USBI_GET_CONTEXT(ctx);
+ struct usbi_event_source *ievent_source;
+ size_t i;
+
+ static_assert(sizeof(struct usbi_event_source_data) == sizeof(struct libusb_pollfd),
+ "mismatch between usbi_event_source_data and libusb_pollfd sizes");
+
+ ctx = usbi_get_context(ctx);
usbi_mutex_lock(&ctx->event_data_lock);
- ret = calloc(ctx->pollfds_cnt + 1, sizeof(struct libusb_pollfd *));
+ i = 0;
+ for_each_event_source(ctx, ievent_source)
+ i++;
+
+ ret = calloc(i + 1, sizeof(struct libusb_pollfd *));
if (!ret)
goto out;
- list_for_each_entry(ipollfd, &ctx->ipollfds, list, struct usbi_pollfd)
- ret[i++] = (struct libusb_pollfd *) ipollfd;
- ret[ctx->pollfds_cnt] = NULL;
+ i = 0;
+ for_each_event_source(ctx, ievent_source)
+ ret[i++] = (struct libusb_pollfd *)ievent_source;
out:
usbi_mutex_unlock(&ctx->event_data_lock);
- return (const struct libusb_pollfd **) ret;
+ return (const struct libusb_pollfd **)ret;
#else
- usbi_err(ctx, "external polling of libusb's internal descriptors "\
- "is not yet supported on Windows platforms");
+ usbi_err(ctx, "external polling of libusb's internal event sources " \
+ "is not yet supported on Windows");
return NULL;
#endif
}
+/** \ingroup libusb_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 do nothing.
+ *
+ * \param pollfds the list of libusb_pollfd structures to free
+ */
+void API_EXPORTED libusb_free_pollfds(const struct libusb_pollfd **pollfds)
+{
+#if !defined(PLATFORM_WINDOWS)
+ free((void *)pollfds);
+#else
+ UNUSED(pollfds);
+#endif
+}
+
/* 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)
+void usbi_handle_disconnect(struct libusb_device_handle *dev_handle)
{
+ struct libusb_context *ctx = HANDLE_CTX(dev_handle);
struct usbi_transfer *cur;
struct usbi_transfer *to_cancel;
- usbi_dbg("device %d.%d",
- handle->dev->bus_number, handle->dev->device_address);
+ usbi_dbg(ctx, "device %d.%d",
+ dev_handle->dev->bus_number, dev_handle->dev->device_address);
/* 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
- * because the completion handler may try to re-submit the transfer
- * 2. the transfers list can change underneath us - if we were to build a
- * list of transfers to complete (while holding lock), the situation
- * might be different by the time we come to free them
- *
- * so we resort to a loop-based approach as below
- *
- * This is safe because transfers are only removed from the
- * flying_transfer list by usbi_handle_transfer_completion and
- * libusb_close, both of which hold the events_lock while doing so,
- * so usbi_handle_disconnect cannot be running at the same time.
- *
- * Note that libusb_submit_transfer also removes the transfer from
- * the flying_transfer list on submission failure, but it keeps the
- * flying_transfer list locked between addition and removal, so
- * usbi_handle_disconnect never sees such transfers.
+ * 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 has been added to the flying transfer list by
+ * libusb_submit_transfer, has failed to submit and
+ * libusb_submit_transfer is waiting for us to release the
+ * flying_transfers_lock to remove it, so we ignore it
*/
while (1) {
- usbi_mutex_lock(&HANDLE_CTX(handle)->flying_transfers_lock);
to_cancel = NULL;
- 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;
+ usbi_mutex_lock(&ctx->flying_transfers_lock);
+ for_each_transfer(ctx, cur) {
+ if (USBI_TRANSFER_TO_LIBUSB_TRANSFER(cur)->dev_handle == dev_handle) {
+ usbi_mutex_lock(&cur->lock);
+ if (cur->state_flags & USBI_TRANSFER_IN_FLIGHT)
+ to_cancel = cur;
+ usbi_mutex_unlock(&cur->lock);
+
+ if (to_cancel)
+ break;
}
- usbi_mutex_unlock(&HANDLE_CTX(handle)->flying_transfers_lock);
+ }
+ usbi_mutex_unlock(&ctx->flying_transfers_lock);
if (!to_cancel)
break;
- usbi_dbg("cancelling transfer %p from disconnect",
+ usbi_dbg(ctx, "cancelling transfer %p from disconnect",
USBI_TRANSFER_TO_LIBUSB_TRANSFER(to_cancel));
- usbi_backend->clear_transfer_priv(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