X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=src%2Fbin%2Flttng-sessiond%2Fthread-utils.cpp;fp=src%2Fbin%2Flttng-sessiond%2Fthread-utils.cpp;h=1eb25eabe6e09cf753413ad17c9a79e1e2fa9d3b;hb=7966af5763c4aaca39df9bbfa9277ff15715c720;hp=0000000000000000000000000000000000000000;hpb=3a5f70173aa04d11ccb22694d5d31a702cad33ab;p=lttng-tools.git

diff --git a/src/bin/lttng-sessiond/thread-utils.cpp b/src/bin/lttng-sessiond/thread-utils.cpp
new file mode 100644
index 000000000..1eb25eabe
--- /dev/null
+++ b/src/bin/lttng-sessiond/thread-utils.cpp
@@ -0,0 +1,142 @@
+/*
+ * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
+ * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * Copyright (C) 2013 Jérémie Galarneau <jeremie.galarneau@efficios.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-only
+ *
+ */
+
+#include "lttng-sessiond.h"
+#include "utils.h"
+#include <common/utils.h>
+#include <pthread.h>
+
+/*
+ * 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 };
+
+/*
+ * Init thread quit pipe.
+ *
+ * Return -1 on error or 0 if all pipes are created.
+ */
+static int __init_thread_quit_pipe(int *a_pipe)
+{
+	int ret, i;
+
+	ret = pipe(a_pipe);
+	if (ret < 0) {
+		PERROR("thread quit pipe");
+		goto error;
+	}
+
+	for (i = 0; i < 2; i++) {
+		ret = fcntl(a_pipe[i], F_SETFD, FD_CLOEXEC);
+		if (ret < 0) {
+			PERROR("fcntl");
+			goto error;
+		}
+	}
+
+error:
+	return ret;
+}
+
+int sessiond_init_thread_quit_pipe(void)
+{
+	return __init_thread_quit_pipe(thread_quit_pipe);
+}
+
+int sessiond_check_thread_quit_pipe(int fd, uint32_t events)
+{
+	return (fd == thread_quit_pipe[0] && (events & LPOLLIN));
+}
+
+/*
+ * Wait for a notification on the quit pipe (with a timeout).
+ *
+ * A timeout value of -1U means no timeout.
+ *
+ * Returns 1 if the caller should quit, 0 if the timeout was reached, and
+ * -1 if an error was encountered.
+ */
+int sessiond_wait_for_quit_pipe(int timeout_ms)
+{
+	int ret;
+	struct lttng_poll_event events;
+
+	ret = lttng_poll_create(&events, 1, LTTNG_CLOEXEC);
+	if (ret < 0) {
+		PERROR("Failed to initialize poll/epoll set");
+		ret = -1;
+		goto end;
+	}
+	ret = lttng_poll_add(&events, thread_quit_pipe[0], LPOLLIN | LPOLLERR);
+	if (ret < 0) {
+		PERROR("Failed to add file descriptor to poll/epoll set");
+		ret = -1;
+		goto end_clean_poll;
+	}
+	ret = lttng_poll_wait(&events, timeout_ms);
+	if (ret > 0) {
+		/* Should quit. */
+		ret = 1;
+	} else if (ret < 0 && errno != EINTR) {
+		/* Unknown error. */
+		PERROR("Failed to epoll()/poll() thread quit pipe");
+		ret = -1;
+	} else {
+		/* Timeout reached. */
+		ret = 0;
+	}
+end_clean_poll:
+	lttng_poll_clean(&events);
+end:
+	return ret;
+}
+
+int sessiond_notify_quit_pipe(void)
+{
+	return notify_thread_pipe(thread_quit_pipe[1]);
+}
+
+void sessiond_close_quit_pipe(void)
+{
+	utils_close_pipe(thread_quit_pipe);
+}
+
+static
+int __sessiond_set_thread_pollset(struct lttng_poll_event *events, size_t size,
+		int *a_pipe)
+{
+	int ret;
+
+	LTTNG_ASSERT(events);
+
+	ret = lttng_poll_create(events, size, LTTNG_CLOEXEC);
+	if (ret < 0) {
+		goto error;
+	}
+
+	/* Add quit pipe */
+	ret = lttng_poll_add(events, a_pipe[0], LPOLLIN | LPOLLERR);
+	if (ret < 0) {
+		goto error;
+	}
+
+	return 0;
+
+error:
+	return ret;
+}
+
+/*
+ * Create a poll set with O_CLOEXEC and add the thread quit pipe to the set.
+ */
+int sessiond_set_thread_pollset(struct lttng_poll_event *events, size_t size)
+{
+	return __sessiond_set_thread_pollset(events, size, thread_quit_pipe);
+}