TetherController.cpp: add O_CLOEXEC

Don't leak open file descriptors across execs to netd's children. This
can occur in the unlikely but theoretically possible event that one
thread is in writeToFile() and another thread happens to call exec().

Test: device boots with no obvious problems.
Change-Id: Iabd8eee46bf94d70894ca46e58484ccb8241513a

1 files changed, 1 insertions, 1 deletions

diff --git a/server/TetherController.cpp b/server/TetherController.cpp
index 6617c6a5..7bf4a925 100644
--- a/server/TetherController.cpp
+++ b/server/TetherController.cpp
@@ -46,7 +46,7 @@ const char IPV6_FORWARDING_PROC_FILE[] = "/proc/sys/net/ipv6/conf/all/forwarding
 const char SEPARATOR[] = "|";
 
 bool writeToFile(const char* filename, const char* value) {
-    int fd = open(filename, O_WRONLY);
+    int fd = open(filename, O_WRONLY | O_CLOEXEC);
     if (fd < 0) {
         ALOGE("Failed to open %s: %s", filename, strerror(errno));
         return false;