[lxc-devel] [lxc/master] utils: handle > 2^31 in lxc_unstack_mountpoint()

[brauner on Github]

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From 640bfdfed1ef117f01dedb100afca9281c4467df Mon Sep 17 00:00:00 2001
From: Christian Brauner <christian.brauner at ubuntu.com>
Date: Wed, 10 May 2017 16:56:37 +0200
Subject: [PATCH] utils: handle > 2^31 in lxc_unstack_mountpoint()

I mean.. really? But better safe than sorry.

Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>
---
 src/lxc/utils.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/src/lxc/utils.c b/src/lxc/utils.c
index ae23d40..a14e1ea 100644
--- a/src/lxc/utils.c
+++ b/src/lxc/utils.c
@@ -2208,7 +2208,7 @@ int lxc_prepare_loop_dev(const char *source, char *loop_dev, int flags)
 int lxc_unstack_mountpoint(const char *path, bool lazy)
 {
 	int ret;
-	int umounts = 0;
+	long int umounts = 0;
 
 pop_stack:
 	ret = umount2(path, lazy ? MNT_DETACH : 0);
@@ -2221,12 +2221,17 @@ int lxc_unstack_mountpoint(const char *path, bool lazy)
 		if (errno != EINVAL)
 			return -errno;
 	} else {
+		/* Just stop counting when this happens. That'd just be so
+		 * stupid that we won't even bother trying to report back the
+		 * correct value anymore.
+		 */
+		if ((long) (int) umounts == umounts)
+			umounts++;
 		/* We succeeded in umounting. Make sure that there's no other
 		 * mountpoint stacked underneath.
 		 */
-		umounts++;
 		goto pop_stack;
 	}
 
-	return umounts;
+	return (int)umounts;
 }