From 8075e4f6c9904189ea04a853b5480451ec74e67d Mon Sep 17 00:00:00 2001
From: Christian Brauner <christian.brauner@ubuntu.com>
Date: Sat, 8 May 2021 14:15:41 +0200
Subject: tests/cgroup: move cg_wait_for(), cg_prepare_for_wait()

as they will be used by the tests for cgroup killing.

Link: https://lore.kernel.org/r/20210503143922.3093755-4-brauner@kernel.org
Cc: Tejun Heo <tj@kernel.org>
Cc: cgroups@vger.kernel.org
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
---
 tools/testing/selftests/cgroup/cgroup_util.c | 47 ++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)

(limited to 'tools/testing/selftests/cgroup/cgroup_util.c')

diff --git a/tools/testing/selftests/cgroup/cgroup_util.c b/tools/testing/selftests/cgroup/cgroup_util.c
index f60f7d764690..623cec04ad42 100644
--- a/tools/testing/selftests/cgroup/cgroup_util.c
+++ b/tools/testing/selftests/cgroup/cgroup_util.c
@@ -5,10 +5,12 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <linux/limits.h>
+#include <poll.h>
 #include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <sys/inotify.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <sys/wait.h>
@@ -580,3 +582,48 @@ int clone_into_cgroup_run_wait(const char *cgroup)
 	(void)clone_reap(pid, WEXITED);
 	return 0;
 }
+
+int cg_prepare_for_wait(const char *cgroup)
+{
+	int fd, ret = -1;
+
+	fd = inotify_init1(0);
+	if (fd == -1)
+		return fd;
+
+	ret = inotify_add_watch(fd, cg_control(cgroup, "cgroup.events"),
+				IN_MODIFY);
+	if (ret == -1) {
+		close(fd);
+		fd = -1;
+	}
+
+	return fd;
+}
+
+int cg_wait_for(int fd)
+{
+	int ret = -1;
+	struct pollfd fds = {
+		.fd = fd,
+		.events = POLLIN,
+	};
+
+	while (true) {
+		ret = poll(&fds, 1, 10000);
+
+		if (ret == -1) {
+			if (errno == EINTR)
+				continue;
+
+			break;
+		}
+
+		if (ret > 0 && fds.revents & POLLIN) {
+			ret = 0;
+			break;
+		}
+	}
+
+	return ret;
+}
-- 
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