Teach rdate to timeout in 10 seconds to avoid blocking forever

with odd or broken networking setups

diff --git a/util-linux/rdate.c b/util-linux/rdate.c
index a5699ebf4d1808a593dc33eb729a7f75961f00e3..cb180247e026115fbffae4a2075fde73476adc27 100644 (file)
--- a/util-linux/rdate.c
+++ b/util-linux/rdate.c
@@ -32,11 +32,17 @@
 #include <time.h>
 #include <stdlib.h>
 #include <unistd.h>
+#include <signal.h>
 #include "busybox.h"
 
 
 static const int RFC_868_BIAS = 2208988800UL;
 
+static void socket_timeout()
+{
+       bb_error_msg_and_die("timeout connecting to time server\n");
+}
+
 static time_t askremotedate(const char *host)
 {
        unsigned long int nett, localt;
@@ -46,6 +52,10 @@ static time_t askremotedate(const char *host)
        if (getservbyname("time", "tcp") != NULL)
                port="time";
 
+       /* Add a timeout for dead or non accessable servers */
+       alarm(10);
+       signal(SIGALRM, socket_timeout);
+
        fd = xconnect(host, port);
 
        if (safe_read(fd, (void *)&nett, 4) != 4)    /* read time from server */