merge branch 'pr-2018'

Lifubang (1):
  add prompt when rootless users have no read access to runc bin

LGTMs: @AkihiroSuda @cyphar
Closes opencontainers#2018

libcontainer/nsenter/cloned_binary.c

@@ -119,8 +119,10 @@ static int is_self_cloned(void)
 	struct statfs fsbuf = {};
 
 	fd = open("/proc/self/exe", O_RDONLY|O_CLOEXEC);
-	if (fd < 0)
+	if (fd < 0) {
+		fprintf(stderr, "you have no read access to runc binary file\n");
 		return -ENOTRECOVERABLE;
+	}
 
 	/*
 	 * Is the binary a fully-sealed memfd? We don't need CLONED_BINARY_ENV for