--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/sw/sniff-rx/mainloop.c	Tue Aug 22 06:16:44 2023 +0000
@@ -0,0 +1,61 @@
+/*
+ * This module holds our main loop code, factored out into a separate
+ * function that is called from main() after initialization.
+ */
+
+#include <sys/types.h>
+#include <sys/time.h>
+#include <sys/errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+extern int target_fd;
+extern FILE *main_outf;
+
+struct timeval curtime;
+
+main_loop()
+{
+	fd_set fds;
+	struct timeval tv;
+	u_char buf[512];
+	int cc, i, is_active;
+
+	for (is_active = 0; ; ) {
+		FD_ZERO(&fds);
+		FD_SET(target_fd, &fds);
+		if (is_active) {
+			tv.tv_sec = 1;
+			tv.tv_usec = 0;
+			cc = select(target_fd+1, &fds, 0, 0, &tv);
+		} else
+			cc = select(target_fd+1, &fds, 0, 0, 0);
+		gettimeofday(&curtime, 0);
+		if (cc < 0) {
+			if (errno == EINTR)
+				continue;
+			perror("select");
+			exit(1);
+		}
+		if (cc == 0) {
+			is_active = 0;
+			fflush(main_outf);
+			flush_pending_byte();
+			continue;
+		}
+		cc = read(target_fd, buf, sizeof buf);
+		if (cc < 0) {
+			perror("serial port read");
+			exit(1);
+		}
+		if (cc == 0) {
+			fprintf(stderr, "read EOF from serial port\n");
+			exit(1);
+		}
+		current_date_time();
+		for (i = 0; i < cc; i++)
+			rx_byte_in(buf[i]);
+		is_active = 1;
+	}
+}