bin: compile lttng-sessiond as C++

[lttng-tools.git] / src / bin / lttng-sessiond / thread-utils.cpp

diff --git a/src/bin/lttng-sessiond/thread-utils.cpp b/src/bin/lttng-sessiond/thread-utils.cpp
new file mode 100644 (file)
index 0000000..1eb25ea
--- /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);
+}