+/*
+ * Copyright (C) 2022 EfficiOS Inc.
+ *
+ * SPDX-License-Identifier: GPL-2.0-only
+ *
+ */
+
+#include "lttng-relayd.hpp"
+
+#include <common/compat/poll.hpp>
+#include <common/error.hpp>
+#include <common/fd-tracker/utils.hpp>
+#include <common/readwrite.hpp>
+#include <common/utils.hpp>
+
+/*
+ * Quit pipe for all threads. This permits a single cancellation point
+ * for all threads when receiving an event on the pipe.
+ */
+static int thread_quit_pipe[2] = { -1, -1 };
+
+/*
+ * Write to writable pipe used to notify a thread.
+ */
+static int notify_thread_pipe(int wpipe)
+{
+ const auto ret = lttng_write(wpipe, "!", 1);
+
+ if (ret < 1) {
+ PERROR("Failed to write to thread pipe");
+ return -1;
+ }
+
+ return 0;
+}
+
+/*
+ * Initialize the thread quit pipe.
+ *
+ * Return -1 on error or 0 if all pipes are created.
+ */
+int relayd_init_thread_quit_pipe(void)
+{
+ return fd_tracker_util_pipe_open_cloexec(
+ the_fd_tracker, "Thread quit pipe", thread_quit_pipe);
+}
+
+/*
+ * Notify the threads to initiate shutdown.
+ *
+ * Return 0 on success or -1 on error.
+ */
+int relayd_notify_thread_quit_pipe(void)
+{
+ return notify_thread_pipe(thread_quit_pipe[1]);
+}
+
+/*
+ * Close the thread quit pipe.
+ */
+void relayd_close_thread_quit_pipe(void)
+{
+ if (thread_quit_pipe[0] != -1) {
+ (void) fd_tracker_util_pipe_close(
+ the_fd_tracker, thread_quit_pipe);
+ }
+}
+
+/*
+ * Return 1 if 'fd' is the thread quit pipe read fd.
+ */
+bool relayd_is_thread_quit_pipe(const int fd)
+{
+ return (fd == thread_quit_pipe[0]);
+}
+
+/*
+ * Create a poll set with O_CLOEXEC and add the thread quit pipe to the set.
+ */
+int create_named_thread_poll_set(struct lttng_poll_event *events,
+ int size, const char *name)
+{
+ if (events == NULL || size == 0) {
+ return -1;
+ }
+
+ const auto create_ret = fd_tracker_util_poll_create(the_fd_tracker,
+ name, events, 1, LTTNG_CLOEXEC);
+ if (create_ret) {
+ PERROR("Failed to create \"%s\" poll file descriptor", name);
+ return -1;
+ }
+
+ /* Add thread quit pipe to monitored events. */
+ const auto poll_add_ret = lttng_poll_add(events, thread_quit_pipe[0], LPOLLIN | LPOLLERR);
+ if (poll_add_ret < 0) {
+ return -1;
+ }
+
+ return 0;
+}