VERITAS File System 4.1 Administrator's Guide

File Change Log

File Change Log Programmatic Interface

Chapter 8 135

File Change Log Programmatic Interface

The standard system calls open(2), lseek(2), read(2) and close(2) can be used on the

FCL ﬁle at mount_point/lost+found/changelog. Only one programmatic interface is

exposed through libvxfsutil, the vxfsu_fcl_sync API (see the vxfsu_fcl_sync(3) manual

page). The prototype is available at /opt/VRTSfssdk/4.0/include/vxfsutil.h.

The following sample code fragment reads the FCL superblock, checks that the state of the

FCL is VX_FCLS_ON, issues a call to vxfsu_fcl_sync to obtain a ﬁnishing offset to read to,

determines the ﬁrst valid offset in the FCL ﬁle, then reads the entries in 8K chunks from this

offset. The section process fcl entries is what an application developer must supply to process

the entries in the FCL.

#include <stdint.h>

#include <stdio.h>

#include <stdlib.h>

#include <sys/types.h>

#include <sys/fcntl.h>

#include <errno.h>

#include <fcl.h>

#include <vxfsutil.h>

#define FCL_READSZ 8192

char* fclname = "/mnt/lost+found/changelog";

int

read_fcl(fclname)

char* fclname;

{

struct fcl_sb fclsb;

uint64_t off, lastoff;

size_t size;

char buf[FCL_READSZ], *bufp = buf;

int fd;

int err = 0;