mdadm: Unify forks behaviour

If mdadm is run by udev or systemd, it gets a pipe as each stream.
Forks in the background may run after an event or service has been
processed when udev is detached from pipe. As a result process
fails quietly if any message is written.
To prevent from it, each fork has to close all parent streams. Leave
stderr and stdout opened only for debug purposes.
Unify it across all forks. Introduce other descriptors detection by
scanning /proc/self/fd directory. Add generic method for
managing systemd services.

Signed-off-by: Mariusz Tkaczyk <mariusz.tkaczyk@intel.com>

1 files changed, 1 insertions, 8 deletions

diff --git a/mdmon.c b/mdmon.c
index ff985d2..c71e62c 100644
--- a/mdmon.c
+++ b/mdmon.c
@@ -546,14 +546,7 @@ static int mdmon(char *devnm, int must_fork, int takeover)
 	}
 
 	setsid();
-	close(0);
-	open("/dev/null", O_RDWR);
-	close(1);
-	ignore = dup(0);
-#ifndef DEBUG
-	close(2);
-	ignore = dup(0);
-#endif
+	manage_fork_fds(0);
 
 	/* This silliness is to stop the compiler complaining
 	 * that we ignore 'ignore'