From cb81159ce49380d39c80f803353784633b8f306c Mon Sep 17 00:00:00 2001
From: "S. Fan" <sfanxiang@gmail.com>
Date: Mon, 31 Jul 2017 05:10:10 -0500
Subject: [PATCH] rfkill: fix erroneous behavior when polling the udev monitor
 (#6489)

Comparing udev_device_get_sysname(device) and sysname will always return
true. We need to check the device received from udev monitor instead.

Also, fd_wait_for_event() sometimes never exits. Better set a timeout
here.

(cherry picked from commit 8ec1a07998758f6a85f3ea5bf2ed14d87609398f)
---
 src/rfkill/rfkill.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/rfkill/rfkill.c b/src/rfkill/rfkill.c
index c0f138b4f4..470853d1d2 100644
--- a/src/rfkill/rfkill.c
+++ b/src/rfkill/rfkill.c
@@ -138,17 +138,21 @@ static int wait_for_initialized(
         for (;;) {
                 _cleanup_udev_device_unref_ struct udev_device *t = NULL;
 
-                r = fd_wait_for_event(watch_fd, POLLIN, USEC_INFINITY);
+                r = fd_wait_for_event(watch_fd, POLLIN, EXIT_USEC);
                 if (r == -EINTR)
                         continue;
                 if (r < 0)
                         return log_error_errno(r, "Failed to watch udev monitor: %m");
+                if (r == 0) {
+                        log_error("Timed out wating for udev monitor.");
+                        return -ETIMEDOUT;
+                }
 
                 t = udev_monitor_receive_device(monitor);
                 if (!t)
                         continue;
 
-                if (streq_ptr(udev_device_get_sysname(device), sysname)) {
+                if (streq_ptr(udev_device_get_sysname(t), sysname)) {
                         *ret = udev_device_ref(t);
                         return 0;
                 }