Initial

1 files changed, 300 insertions, 0 deletions

diff --git a/src/os/events_posix.c b/src/os/events_posix.c
new file mode 100644
index 0000000..715a2d5
--- /dev/null
+++ b/src/os/events_posix.c
@@ -0,0 +1,300 @@
+/*
+ * 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(ctx, "poll() %u fds with timeout in %dms", (unsigned int)nfds, timeout_ms);
+	num_ready = poll(fds, nfds, timeout_ms);
+	usbi_dbg(ctx, "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
+
+	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(ctx, "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;
+}