X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fbin%2Flttng-sessiond%2Fthread-utils.c;fp=src%2Fbin%2Flttng-sessiond%2Fthread-utils.c;h=99b8298983fa6a7a8f489bcb7222a198b6d217dc;hp=0000000000000000000000000000000000000000;hb=a7333da73c2083281c5ec833d041b7acf0d10d0b;hpb=c6db3843828a8fbf08444a2bc4191291a4807936

diff --git a/src/bin/lttng-sessiond/thread-utils.c b/src/bin/lttng-sessiond/thread-utils.c
new file mode 100644
index 000000000..99b829898
--- /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);
+}