Merge remote-tracking branch 'origin/mdb.master' into OPENLDAP_REL_ENG_2_4

[openldap] / libraries / liblutil / lockf.c

diff --git a/libraries/liblutil/lockf.c b/libraries/liblutil/lockf.c
index 7307720dd68744af161365b245c2762fb73e092b..6119721a5f161ea74dec96c1bd16175b1f15f99d 100644 (file)
--- a/libraries/liblutil/lockf.c
+++ b/libraries/liblutil/lockf.c
@@ -1,39 +1,118 @@
-/*
- * Copyright 1998,1999 The OpenLDAP Foundation, Redwood City, California, USA
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 1998-2013 The OpenLDAP Foundation.
  * All rights reserved.
  *
- * Redistribution and use in source and binary forms are permitted only
- * as authorized by the OpenLDAP Public License.  A copy of this
- * license is available at http://www.OpenLDAP.org/license.html or
- * in file LICENSE in the top-level directory of the distribution.
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted only as authorized by the OpenLDAP
+ * Public License.
+ *
+ * A copy of this license is available in the file LICENSE in the
+ * top-level directory of the distribution or, alternatively, at
+ * <http://www.OpenLDAP.org/license.html>.
+ */
+
+/*
+ * File Locking Routines
+ *
+ * Implementations (in order of preference)
+ *     - lockf
+ *     - fcntl
+ *  - flock
+ *
+ * Other implementations will be added as needed.
+ *
+ * NOTE: lutil_lockf() MUST block until an exclusive lock is acquired.
  */
-/* File locking methods */
 
 #include "portable.h"
 
 #include <stdio.h>
 #include <ac/unistd.h>
 
-#if defined(NEED_FCNTL_LOCKING)
+#undef LOCK_API
+
+#if defined(HAVE_LOCKF) && defined(F_LOCK)
+#      define USE_LOCKF 1
+#      define LOCK_API "lockf"
+#endif
+
+#if !defined(LOCK_API) && defined(HAVE_FCNTL)
+#      ifdef HAVE_FCNTL_H
+#              include <fcntl.h>
+#      endif
+#      ifdef F_WRLCK
+#              define USE_FCNTL 1
+#              define LOCK_API "fcntl"
+#      endif
+#endif
+
+#if !defined(LOCK_API) && defined(HAVE_FLOCK)
+#      ifdef HAVE_SYS_FILE_H
+#              include <sys/file.h>
+#      endif
+#      define USE_FLOCK 1
+#      define LOCK_API "flock"
+#endif
+
+#if !defined(USE_LOCKF) && !defined(USE_FCNTL) && !defined(USE_FLOCK)
+int lutil_lockf ( int fd ) {
+    fd = fd;
+    return 0;
+}
 
-int lutil_lockf ( FILE *fp ) {
+int lutil_unlockf ( int fd ) {
+    fd = fd;
+    return 0;
+}
+#endif
+
+#ifdef USE_LOCKF
+int lutil_lockf ( int fd ) {
+       /* use F_LOCK instead of F_TLOCK, ie: block */
+       return lockf( fd, F_LOCK, 0 );
+}
+
+int lutil_unlockf ( int fd ) {
+       return lockf( fd, F_ULOCK, 0 );
+}
+#endif
+
+#ifdef USE_FCNTL
+int lutil_lockf ( int fd ) {
        struct flock file_lock;
-       memset( &file_lock, 0, sizeof( file_lock ) );
+
+       memset( &file_lock, '\0', sizeof( file_lock ) );
        file_lock.l_type = F_WRLCK;
        file_lock.l_whence = SEEK_SET;
        file_lock.l_start = 0;
        file_lock.l_len = 0;
-       return( fcntl( fileno(fp), F_SETLKW, &file_lock ) );
+
+       /* use F_SETLKW instead of F_SETLK, ie: block */
+       return( fcntl( fd, F_SETLKW, &file_lock ) );
 }
 
-int lutil_unlockf ( FILE *fp ) {
+int lutil_unlockf ( int fd ) {
        struct flock file_lock;
-       memset( &file_lock, 0, sizeof( file_lock ) );
+
+       memset( &file_lock, '\0', sizeof( file_lock ) );
        file_lock.l_type = F_UNLCK;
        file_lock.l_whence = SEEK_SET;
        file_lock.l_start = 0;
        file_lock.l_len = 0;
-       return ( fcntl( fileno(fp), F_SETLK, &file_lock ) );
+
+       return( fcntl ( fd, F_SETLKW, &file_lock ) );
 }
+#endif
 
-#endif /* !HAVE_FILE_LOCKING */
+#ifdef USE_FLOCK
+int lutil_lockf ( int fd ) {
+       /* use LOCK_EX instead of LOCK_EX|LOCK_NB, ie: block */
+       return flock( fd, LOCK_EX );
+}
+
+int lutil_unlockf ( int fd ) {
+       return flock( fd, LOCK_UN );
+}
+#endif