1 files changed, 62 insertions, 0 deletions
diff --git a/src/port/lockf.c b/src/port/lockf.c
new file mode 100644
index 0000000..09c613e
--- /dev/null
+++ b/src/port/lockf.c
@@ -0,0 +1,62 @@
+#include "lockf.h"
+
+#include "string.h"		/* for memset */
+#include "unistd.h"		/* for getpid */
+
+#if !defined HAVE_LOCKF
+
+#include <sys/types.h>		/* for off_t */
+#include <errno.h>		/* for errno */
+
+int lockf( int fd, int cmd, off_t len ) {
+	struct flock fl;
+	
+	memset( (char *)&fl, 0, sizeof( fl ) );
+	/* lockf is always relative to the current file position. */
+	fl.l_whence = SEEK_CUR;
+	fl.l_start = 0;
+	fl.l_len = len;
+	
+	errno = 0;
+	
+	switch( cmd ) {
+		case F_TEST:
+			fl.l_type = F_RDLCK;
+			if( fcntl( fd, F_GETLK, &fl ) < 0 ) {
+				return -1;
+			}
+			if( fl.l_type == F_UNLCK ||
+			    fl.l_pid == getpid( ) ) {
+				return 0;
+			}
+			errno = EACCES;
+			return -1;
+			
+		case F_ULOCK:
+			fl.l_type = F_UNLCK;
+			cmd = F_SETLK;
+			break;
+		
+		case F_LOCK:
+			fl.l_type = F_WRLCK;
+			cmd = F_SETLKW;
+			break;
+		
+		case F_TLOCK:
+			fl.l_type = F_WRLCK;
+			cmd = F_SETLK; 
+			break;
+			
+		default:
+			errno = EINVAL;
+			return -1;
+	}
+	
+	return fcntl( fd, cmd, &fl );
+}
+
+#else
+
+extern int dummy;		/* prevent ISO C forbids an empty source file' warning */
+
+#endif /* !defined HAVE_LOCKF */