implement LPT pin "reset" function

yasnd.c

@@ -1,5 +1,6 @@
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <sys/io.h>
 #include <sys/wait.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -130,6 +131,30 @@ void check_host(int num,host_decl* host)
 	host->helper_pid=pid;
 }
 
+/*
+	Function, that turn on only one LPT port pin, defined by it argument, wait a second,
+	and turn off all pins. That is enough to reset specified host.
+*/
+void reset_pin(int pin_num)
+{
+	if (pin_num<1 || pin_num>8)
+	{
+		log_event("Error: incorrent LPT pin number");
+		return;
+	}
+	#define LPTPORT 0x378
+	int pins = 2<<(pin_num-1);
+	if (ioperm (LPTPORT, 3, 1))
+	{
+		log_event("Error: LPT port access error");
+		exit(EXIT_FAILURE);
+	}
+	// Reset host
+	outb (pins, LPTPORT);
+	sleep(1);
+	outb (0, LPTPORT);
+}
+
 void loop_function()
 {
 	for (int i=0;i<hosts_count;i++)