blob: 952ea5f1e019f2287e2efe0124ca71d442245c92 [file] [log] [blame]
/*
* libusb event abstraction on POSIX platforms
*
* Copyright © 2020 Chris Dickens <christopher.a.dickens@gmail.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libusbi.h"
#include <errno.h>
#include <fcntl.h>
#ifdef HAVE_EVENTFD
#include <sys/eventfd.h>
#endif
#ifdef HAVE_TIMERFD
#include <sys/timerfd.h>
#endif
#include <unistd.h>
#ifdef HAVE_EVENTFD
#define EVENT_READ_FD(e) ((e)->eventfd)
#define EVENT_WRITE_FD(e) ((e)->eventfd)
#else
#define EVENT_READ_FD(e) ((e)->pipefd[0])
#define EVENT_WRITE_FD(e) ((e)->pipefd[1])
#endif
#ifdef HAVE_NFDS_T
typedef nfds_t usbi_nfds_t;
#else
typedef unsigned int usbi_nfds_t;
#endif
int usbi_create_event(usbi_event_t *event)
{
#ifdef HAVE_EVENTFD
event->eventfd = eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC);
if (event->eventfd == -1) {
usbi_err(NULL, "failed to create eventfd, errno=%d", errno);
return LIBUSB_ERROR_OTHER;
}
return 0;
#else
#if defined(HAVE_PIPE2)
int ret = pipe2(event->pipefd, O_CLOEXEC);
#else
int ret = pipe(event->pipefd);
#endif
if (ret != 0) {
usbi_err(NULL, "failed to create pipe, errno=%d", errno);
return LIBUSB_ERROR_OTHER;
}
#if !defined(HAVE_PIPE2) && defined(FD_CLOEXEC)
ret = fcntl(event->pipefd[0], F_GETFD);
if (ret == -1) {
usbi_err(NULL, "failed to get pipe fd flags, errno=%d", errno);
goto err_close_pipe;
}
ret = fcntl(event->pipefd[0], F_SETFD, ret | FD_CLOEXEC);
if (ret == -1) {
usbi_err(NULL, "failed to set pipe fd flags, errno=%d", errno);
goto err_close_pipe;
}
ret = fcntl(event->pipefd[1], F_GETFD);
if (ret == -1) {
usbi_err(NULL, "failed to get pipe fd flags, errno=%d", errno);
goto err_close_pipe;
}
ret = fcntl(event->pipefd[1], F_SETFD, ret | FD_CLOEXEC);
if (ret == -1) {
usbi_err(NULL, "failed to set pipe fd flags, errno=%d", errno);
goto err_close_pipe;
}
#endif
ret = fcntl(event->pipefd[1], F_GETFL);
if (ret == -1) {
usbi_err(NULL, "failed to get pipe fd status flags, errno=%d", errno);
goto err_close_pipe;
}
ret = fcntl(event->pipefd[1], F_SETFL, ret | O_NONBLOCK);
if (ret == -1) {
usbi_err(NULL, "failed to set pipe fd status flags, errno=%d", errno);
goto err_close_pipe;
}
return 0;
err_close_pipe:
close(event->pipefd[1]);
close(event->pipefd[0]);
return LIBUSB_ERROR_OTHER;
#endif
}
void usbi_destroy_event(usbi_event_t *event)
{
#ifdef HAVE_EVENTFD
if (close(event->eventfd) == -1)
usbi_warn(NULL, "failed to close eventfd, errno=%d", errno);
#else
if (close(event->pipefd[1]) == -1)
usbi_warn(NULL, "failed to close pipe write end, errno=%d", errno);
if (close(event->pipefd[0]) == -1)
usbi_warn(NULL, "failed to close pipe read end, errno=%d", errno);
#endif
}
void usbi_signal_event(usbi_event_t *event)
{
uint64_t dummy = 1;
ssize_t r;
r = write(EVENT_WRITE_FD(event), &dummy, sizeof(dummy));
if (r != sizeof(dummy))
usbi_warn(NULL, "event write failed");
}
void usbi_clear_event(usbi_event_t *event)
{
uint64_t dummy;
ssize_t r;
r = read(EVENT_READ_FD(event), &dummy, sizeof(dummy));
if (r != sizeof(dummy))
usbi_warn(NULL, "event read failed");
}
#ifdef HAVE_TIMERFD
int usbi_create_timer(usbi_timer_t *timer)
{
timer->timerfd = timerfd_create(CLOCK_MONOTONIC, TFD_NONBLOCK | TFD_CLOEXEC);
if (timer->timerfd == -1) {
usbi_warn(NULL, "failed to create timerfd, errno=%d", errno);
return LIBUSB_ERROR_OTHER;
}
return 0;
}
void usbi_destroy_timer(usbi_timer_t *timer)
{
if (close(timer->timerfd) == -1)
usbi_warn(NULL, "failed to close timerfd, errno=%d", errno);
}
int usbi_arm_timer(usbi_timer_t *timer, const struct timespec *timeout)
{
const struct itimerspec it = { { 0, 0 }, { timeout->tv_sec, timeout->tv_nsec } };
if (timerfd_settime(timer->timerfd, TFD_TIMER_ABSTIME, &it, NULL) == -1) {
usbi_warn(NULL, "failed to arm timerfd, errno=%d", errno);
return LIBUSB_ERROR_OTHER;
}
return 0;
}
int usbi_disarm_timer(usbi_timer_t *timer)
{
const struct itimerspec it = { { 0, 0 }, { 0, 0 } };
if (timerfd_settime(timer->timerfd, 0, &it, NULL) == -1) {
usbi_warn(NULL, "failed to disarm timerfd, errno=%d", errno);
return LIBUSB_ERROR_OTHER;
}
return 0;
}
#endif
int usbi_alloc_event_data(struct libusb_context *ctx)
{
struct usbi_event_source *ievent_source;
struct pollfd *fds;
size_t i = 0;
if (ctx->event_data) {
free(ctx->event_data);
ctx->event_data = NULL;
}
ctx->event_data_cnt = 0;
for_each_event_source(ctx, ievent_source)
ctx->event_data_cnt++;
fds = calloc(ctx->event_data_cnt, sizeof(*fds));
if (!fds)
return LIBUSB_ERROR_NO_MEM;
for_each_event_source(ctx, ievent_source) {
fds[i].fd = ievent_source->data.os_handle;
fds[i].events = ievent_source->data.poll_events;
i++;
}
ctx->event_data = fds;
return 0;
}
int usbi_wait_for_events(struct libusb_context *ctx,
struct usbi_reported_events *reported_events, int timeout_ms)
{
struct pollfd *fds = ctx->event_data;
usbi_nfds_t nfds = (usbi_nfds_t)ctx->event_data_cnt;
int internal_fds, num_ready;
usbi_dbg("poll() %u fds with timeout in %dms", (unsigned int)nfds, timeout_ms);
num_ready = poll(fds, nfds, timeout_ms);
usbi_dbg("poll() returned %d", num_ready);
if (num_ready == 0) {
if (usbi_using_timer(ctx))
goto done;
return LIBUSB_ERROR_TIMEOUT;
} else if (num_ready == -1) {
if (errno == EINTR)
return LIBUSB_ERROR_INTERRUPTED;
usbi_err(ctx, "poll() failed, errno=%d", errno);
return LIBUSB_ERROR_IO;
}
/* fds[0] is always the internal signalling event */
if (fds[0].revents) {
reported_events->event_triggered = 1;
num_ready--;
} else {
reported_events->event_triggered = 0;
}
#ifdef HAVE_OS_TIMER
/* on timer configurations, fds[1] is the timer */
if (usbi_using_timer(ctx) && fds[1].revents) {
reported_events->timer_triggered = 1;
num_ready--;
} else {
reported_events->timer_triggered = 0;
}
#endif
assert(num_ready > 0);
if (!num_ready)
goto done;
/* the backend will never need to attempt to handle events on the
* library's internal file descriptors, so we determine how many are
* in use internally for this context and skip these when passing any
* remaining pollfds to the backend. */
internal_fds = usbi_using_timer(ctx) ? 2 : 1;
fds += internal_fds;
nfds -= internal_fds;
usbi_mutex_lock(&ctx->event_data_lock);
if (ctx->event_flags & USBI_EVENT_EVENT_SOURCES_MODIFIED) {
struct usbi_event_source *ievent_source;
for_each_removed_event_source(ctx, ievent_source) {
usbi_nfds_t n;
for (n = 0; n < nfds; n++) {
if (ievent_source->data.os_handle != fds[n].fd)
continue;
if (!fds[n].revents)
continue;
/* pollfd was removed between the creation of the fds array and
* here. remove triggered revent as it is no longer relevant. */
usbi_dbg("fd %d was removed, ignoring raised events", fds[n].fd);
fds[n].revents = 0;
num_ready--;
break;
}
}
}
usbi_mutex_unlock(&ctx->event_data_lock);
if (num_ready) {
assert(num_ready > 0);
reported_events->event_data = fds;
reported_events->event_data_count = (unsigned int)nfds;
}
done:
reported_events->num_ready = num_ready;
return LIBUSB_SUCCESS;
}