lock serial device

4 files changed, 41 insertions, 6 deletions

diff --git a/Makefile b/Makefile
index 680783b..2c7d106 100644
--- a/Makefile
+++ b/Makefile
@@ -2,7 +2,7 @@ PREFIX=/usr/local
 
 # web.vala (currently disabled)
 barcode-scanner: main.vala device.vala db.vala ui.vala
-	valac-0.16 --output $@ --pkg posix --pkg linux --pkg libsoup-2.4 --pkg sqlite3 --pkg gtk+-3.0 --pkg gee-1.0 --pkg gmodule-2.0 $^
+	valac-0.16 --output $@ --pkg posix --pkg linux --pkg libsoup-2.4 --pkg sqlite3 --pkg gtk+-3.0 --pkg gee-1.0 --pkg gmodule-2.0 --pkg gio-2.0 $^
 
 shop.db: create_db.sql
 	sqlite3 shop.db < create_db.sql
diff --git a/db.vala b/db.vala
index b6218a9..8adf81d 100644
--- a/db.vala
+++ b/db.vala
@@ -41,7 +41,7 @@ public class Database {
 	public Database(string file) {
 		int rc;
 
-		rc = Sqlite.Database.open (file, out db);
+		rc = Sqlite.Database.open(file, out db);
 		if(rc != Sqlite.OK) {
 			error("could not open database!");
 		}
diff --git a/device.vala b/device.vala
index 0bbc806..6355107 100644
--- a/device.vala
+++ b/device.vala
@@ -19,19 +19,37 @@ public class Device {
 	public int fd=-1;
 	private IOChannel io_read;
 	public int byterate;
+	private File lockfile;
 
 	public signal void received_barcode(string barcode);
 
 	public Device(string device, int rate, int bits, int stopbits) {
 		Posix.speed_t baudrate = Posix.B9600;
 
-		fd = Posix.open(device, Posix.O_RDWR /*| Posix.O_NONBLOCK*/);
+		/* check lock file */
+		lockfile = File.new_for_path("/var/lock/LCK.." + device.replace("/dev/", ""));
+		if(lockfile.query_exists()) {
+			error("device is locked!\n");
+			/* TODO: check pid */
+		}
+
+		try {
+			var pid = "%d\n".printf(Posix.getpid());
+			lockfile.replace_contents(pid.data, null, false, FileCreateFlags.NONE, null);
+
+			fd = Posix.open(device, Posix.O_RDWR /*| Posix.O_NONBLOCK*/);
+
+			if(fd < 0) {
+				fd = -1;
+				lockfile.delete();
+				error("Could not open device!\n");
+			}
 
-		if(fd < 0) {
-			fd = -1;
-			error("Could not open device!\n");
+		} catch(Error e) {
+			error("Could not create lock file: %s!\n", e.message);
 		}
 
+
 		Posix.tcflush(fd, Posix.TCIOFLUSH);
 
 		Posix.tcgetattr(fd, out restoretio);
@@ -140,6 +158,18 @@ public class Device {
 			error("IOChannel: %s", e.message);
 		}
 	}
+
+	~Device() {
+		/* restore old tty config */
+		Posix.tcsetattr(fd, Posix.TCSANOW, restoretio);
+
+		/* close file */
+		Posix.close(fd);
+
+		/* remove lock */
+		lockfile.delete();
+	}
+
 	private bool device_read(IOChannel gio, IOCondition cond) {
 		IOStatus ret;
 		string msg;
diff --git a/main.vala b/main.vala
index cd441e3..1f2c404 100644
--- a/main.vala
+++ b/main.vala
@@ -48,6 +48,11 @@ public static int main(string[] args) {
 	write_to_log("KtT Shop System has been started");
 
 	Gtk.main();
+
+	/* call destructors */
+	dev = null;
+	db  = null;
+
 	return 0;
 }