llmnrd: Poll hostname

Poll "/proc/sys/kernel/hostname" and update the hostname when it was
changed. systemd has a similar mechanism.

Note that the hostname is not polled if it has been provided on the
command line, or if "/proc/sys/kernel/hostname" cannot be opened.

Patch contributed by @tbetker

Fixes #23
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>

1 files changed, 5 insertions, 1 deletions

diff --git a/llmnr.c b/llmnr.c
index f5a3f2a..dc4b72a 100644
--- a/llmnr.c
+++ b/llmnr.c
@@ -42,12 +42,16 @@ static bool llmnr_ipv6 = false;
 /* Host name in DNS name format (length octet + name + 0 byte) */
 static char llmnr_hostname[LLMNR_LABEL_MAX_SIZE + 2];
 
-void llmnr_init(const char *hostname, bool ipv6)
+void llmnr_set_hostname(const char *hostname)
 {
 	llmnr_hostname[0] = strlen(hostname);
 	strncpy(&llmnr_hostname[1], hostname, LLMNR_LABEL_MAX_SIZE);
 	llmnr_hostname[LLMNR_LABEL_MAX_SIZE + 1] = '\0';
+}
 
+void llmnr_init(const char *hostname, bool ipv6)
+{
+	llmnr_set_hostname(hostname);
 	llmnr_ipv6 = ipv6;
 }