Clean-up: move global sessiond symbols out of main.o

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

diff --git a/src/bin/lttng-sessiond/thread-utils.c b/src/bin/lttng-sessiond/thread-utils.c
new file mode 100644 (file)
index 0000000..99b8298
--- /dev/null
+++ b/src/bin/lttng-sessiond/thread-utils.c
@@ -0,0 +1,151 @@
+/*
+ * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
+ *                      Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *               2013 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2 only,
+ * as published by the Free Software Foundation.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "lttng-sessiond.h"
+#include "utils.h"
+#include <common/utils.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).
+ *
+ * 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(unsigned int timeout_us)
+{
+       int ret;
+       fd_set read_fds;
+       struct timeval timeout;
+
+       FD_ZERO(&read_fds);
+       FD_SET(thread_quit_pipe[0], &read_fds);
+       memset(&timeout, 0, sizeof(timeout));
+       timeout.tv_usec = timeout_us;
+
+       while (true) {
+               ret = select(thread_quit_pipe[0] + 1, &read_fds, NULL, NULL,
+                               &timeout);
+               if (ret < 0 && errno == EINTR) {
+                       /* Retry on interrupt. */
+                       continue;
+               } else {
+                       break;
+               }
+       }
+
+       if (ret > 0) {
+               /* Should quit. */
+               ret = 1;
+       } else if (ret < 0 && errno != EINTR) {
+               /* Unknown error. */
+               PERROR("Failed to select() thread quit pipe");
+               ret = -1;
+       } else {
+               /* Timeout reached. */
+               ret = 0;
+       }
+
+       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;
+
+       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);
+}