Added source code

osdep/read.sel

@@ -0,0 +1,90 @@
+/*
+ *  Check whether or not a character is ready to be read, or time out.
+ *  This version uses a select call.
+ *
+ *   Args: time_out -- number of seconds before it will time out.
+ *
+ * Result: NO_OP_IDLE:	  timed out before any chars ready, time_out > 25
+ *         NO_OP_COMMAND: timed out before any chars ready, time_out <= 25
+ *         READ_INTR:	  read was interrupted
+ *         READY_TO_READ: input is available
+ *         BAIL_OUT:	  reading input failed, time to bail gracefully
+ *         PANIC_NOW:	  system call error, die now
+ */
+int
+input_ready(time_out)
+     int time_out;
+{
+     struct timeval tmo;
+     fd_set         readfds, errfds;
+     int	    res;
+
+     fflush(stdout);
+
+     if(time_out > 0){
+         /* Check to see if there are bytes to read with a timeout */
+	 FD_ZERO(&readfds);
+	 FD_ZERO(&errfds);
+	 FD_SET(STDIN_FD, &readfds);
+	 FD_SET(STDIN_FD, &errfds);
+	 tmo.tv_sec  = time_out;
+         tmo.tv_usec = 0; 
+         res = select(STDIN_FD+1, &readfds, 0, &errfds, &tmo);
+         if(res < 0){
+             if(errno == EINTR || errno == EAGAIN)
+               return(READ_INTR);
+
+	     return(BAIL_OUT);
+         }
+
+         if(res == 0){ /* the select timed out */
+	     if(getppid() == 1){
+		 /* Parent is init! */
+	         return(BAIL_OUT);
+	     }
+	       
+	     /*
+	      * "15" is the minimum allowed mail check interval.
+	      * Anything less, and we're being told to cycle thru
+	      * the command loop because some task is pending...
+	      */
+             return(time_out < IDLE_TIMEOUT ? NO_OP_COMMAND : NO_OP_IDLE);
+         }
+     }
+
+     time_of_last_input = time((time_t *) 0);
+     return(READY_TO_READ);
+}
+
+
+/*
+ * Read one character from STDIN.
+ *
+ * Result:           -- the single character read
+ *         READ_INTR -- read was interrupted
+ *         BAIL_OUT  -- read error of some sort
+ */
+int
+read_one_char()
+{
+     int	    res;
+     unsigned char  c;
+
+     res = read(STDIN_FD, &c, 1);
+
+     if(res <= 0){
+	 /*
+	  * Error reading from terminal!
+	  * The only acceptable failure is being interrupted.  If so,
+	  * return a value indicating such...
+	  */
+	 if(res < 0 && errno == EINTR)
+	   return(READ_INTR);
+	 else
+	   return(BAIL_OUT);
+     }
+
+     return((int)c);
+}
+
+