diff --git a/locks.c b/locks.c

index 649ed4a..aa8898c 100644

--- a/locks.c

+++ b/locks.c

@@ -41,6 +41,10 @@

 #define LCK_NODEV    -1

 #define LCK_OPNFAIL  -2

+#endif

+

+#ifdef HAVE_LOCKDEV

+#include <lockdev.h>

 #endif

        char	lock[MAXLINE+1];	/* name of the lockfile */

@@ -58,6 +62,7 @@ static int we_have_lock = FALSE;

 int do_makelock _P0( void )

 {

+#ifndef HAVE_LOCKDEV

 	int fd, pid;

 	char *temp, buf[MAXLINE+1];

 #ifndef HAVE_MKSTEMP

@@ -148,8 +153,26 @@ again:

 		return(FAIL);

 	}

-	lprintf(L_NOISE, "lock made");

 	(void) unlink(temp);

+#else

+        pid_t device_owner;

+

+        device_owner = dev_lock(lock);

+        if (device_owner < 0)

+        {

+                lprintf(L_ERROR, "lock not made: dev_lock(%s) failed", lock);

+                return FAIL;

+        }

+

+        if (device_owner > 0)

+        {

+                lprintf(L_MESG, "lock not made: lock file exists (pid=%d)", device_owner);

+                return FAIL;

+        }

+

+#endif

+

+        lprintf(L_NOISE, "lock made");

 	we_have_lock = TRUE;

 	return(SUCCESS);

 }

@@ -180,8 +203,8 @@ int makelock _P1( (device),

  */

 int steal_lock _P2((device, pid), char * device, int pid )

 {

-    int retcode, is_pid, fd;

-    

+    int retcode = SUCCESS;

+

     lprintf(L_NOISE, "steal_lock(%s) called", device);

     if ( get_lock_name( lock, device ) == NULL )

@@ -190,6 +213,9 @@ int steal_lock _P2((device, pid), char * device, int pid )

 	return FAIL;

     }

+#ifndef HAVE_LOCKDEV

+    int is_pid, fd;

+

     is_pid = readlock(lock);

     if ( is_pid != pid )

@@ -208,6 +234,13 @@ int steal_lock _P2((device, pid), char * device, int pid )

     }

     retcode = lock_write_pid( fd );

+#else

+    if (dev_relock(lock, pid) < 0)

+    {

+            lprintf( L_ERROR, "can't steal lock: dev_relock(%s, %d) failed", device, pid);

+            retcode = FAIL;

+    }

+#endif

     if ( retcode == SUCCESS ) we_have_lock = TRUE;

     return retcode;

@@ -237,7 +270,6 @@ int makelock_file _P1( (file), char * file )

 int checklock _P1( (device), char * device)

 {

     int pid;

-    struct stat st;

     char name[MAXLINE+1];

     if ( get_lock_name( name, device ) == NULL )

@@ -246,6 +278,9 @@ int checklock _P1( (device), char * device)

 	return NO_LOCK;

     }

+#ifndef HAVE_LOCKDEV

+    struct stat st;

+

     if ((stat(name, &st) == FAIL) && errno == ENOENT)

     {

 	lprintf(L_NOISE, "checklock: stat failed, no file");

@@ -270,12 +305,27 @@ int checklock _P1( (device), char * device)

 	(void) unlink(name);

 	return NO_LOCK;

     }

-    

+#else

+    pid = dev_testlock(name);

+

+    if (pid < 0)

+    {

+            lprintf(L_ERROR, "checklock: can't check lockfile, dev_testlock(%s) failed", name);

+            return NO_LOCK;

+    }

+

+    if (pid == 0)

+    {

+            lprintf(L_MESG, "checklock: device not locked");

+            return NO_LOCK;

+    }

+#endif

     lprintf(L_NOISE, "lockfile found, pid=%d", pid );

     return pid;

 }

+#ifndef HAVE_LOCKDEV

 /*

  *	readlock() - read contents of lockfile

  *

@@ -342,6 +392,8 @@ static int lock_write_pid _P1((fd), int fd)

     close(fd);

     return SUCCESS;

 }

+

+#endif

 /*

  *	rmlocks() - remove lockfile

@@ -352,8 +404,13 @@ void rmlocks _P0(void)

     if ( we_have_lock )

     {

 	lprintf( L_NOISE, "removing lock file" );

+#ifndef HAVE_LOCKDEV

 	if ( unlink(lock) == -1 )

 	    lprintf( L_ERROR, "error removing lock file (huh?!)" );

+#else

+        if (dev_unlock(lock, getpid()) < 0)

+             lprintf(L_ERROR, "error removing lock file, dev_unlock(%s) failed", lock);

+#endif

     }

     /* mark lock file as 'not set' */

     we_have_lock = FALSE;

@@ -364,7 +421,21 @@ void rmlocks _P0(void)

  * determine full path + name of the lock file for a given device

  */

-#ifdef SVR4

+#ifdef HAVE_LOCKDEV

+/*

+ * lockdev API provides us with the way to lock device directly, thus lock name

+ * and device name are the same

+ */

+static char *get_lock_name _P2( (lock, device), char *lock, char *device )

+{

+        lprintf(L_NOISE, "get_lock_name(%s) called", device);

+

+        snprintf(lock, MAXLINE, "%s", device);

+        

+        return lock;

+}

+

+#elif SVR4

 /*

  * get_lock_name() - create SVR4 lock file name (Bodo Bauer)

diff --git a/mgetty.h b/mgetty.h

index 64053fd..c6ddd58 100644

--- a/mgetty.h

+++ b/mgetty.h

@@ -277,6 +277,9 @@ int		makelock_file _PROTO(( char * lockname ));

 int		checklock _PROTO((char * device));

 void		rmlocks _PROTO ((void));

 int		steal_lock _PROTO((char * device, int pid ));

+#ifdef HAVE_LOCKDEV

+extern char lockdev_device[MAXLINE + 1];

+#endif

 /* fax stuff */

 void	faxrec _PROTO(( char * spool_dir, unsigned int switchbd,