Viewing file:  ex_apprec_rec.c (3.09 KB) -rw-r--r--
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/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 1996-2004
* Sleepycat Software. All rights reserved.
*
* $Id: ex_apprec_rec.c,v 1.4 2004/01/28 03:36:03 bostic Exp $
*/
/*
* This file is based on the template file ex_apprec_template. Note that
* because ex_apprec_mkdir, like most application-specific recovery functions,
* does not make use of DB-private structures, it has actually been simplified
* significantly.
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
#include <db.h>
#include "ex_apprec.h"
/*
* ex_apprec_mkdir_recover --
* Recovery function for mkdir.
*
* PUBLIC: int ex_apprec_mkdir_recover
* PUBLIC: __P((DB_ENV *, DBT *, DB_LSN *, db_recops, void *));
*/
int
ex_apprec_mkdir_recover(dbenv, dbtp, lsnp, op, info)
DB_ENV *dbenv;
DBT *dbtp;
DB_LSN *lsnp;
db_recops op;
void *info;
{
ex_apprec_mkdir_args *argp;
int ret;
argp = NULL;
/*
* Shut up the compiler--"info" is used for the recovery functions
* belonging to transaction meta-operations such as txn_create, and
* need not concern us here either.
*/
info = NULL;
if ((ret = ex_apprec_mkdir_read(dbenv, dbtp->data, &argp)) != 0)
goto out;
switch (op) {
case DB_TXN_ABORT:
case DB_TXN_BACKWARD_ROLL:
/*
* If we're aborting, we need to remove the directory if it
* exists. We log the trailing zero in pathnames, so we can
* simply pass the data part of the DBT into rmdir as a string.
* (Note that we don't have any alignment guarantees, but for
* a char * this doesn't matter.)
*
* Ignore all errors other than ENOENT; DB may attempt to undo
* or redo operations without knowing whether they have already
* been done or undone, so we should never assume in a recovery
* function that the task definitely needs doing or undoing.
*/
ret = rmdir(argp->dirname.data);
if (ret != 0 && errno != ENOENT)
dbenv->err(dbenv, ret, "Error in abort of mkdir");
else
ret = 0;
break;
case DB_TXN_FORWARD_ROLL:
/*
* The forward direction is just the opposite; here, we ignore
* EEXIST, because the directory may already exist.
*/
ret = mkdir(argp->dirname.data, 0755);
if (ret != 0 && errno != EEXIST)
dbenv->err(dbenv,
ret, "Error in roll-forward of mkdir");
else
ret = 0;
break;
default:
/*
* We might want to handle DB_TXN_PRINT or DB_TXN_APPLY here,
* too, but we don't try to print the log records and aren't
* using replication, so there's no need to in this example.
*/
dbenv->errx(dbenv, "Unexpected operation type\n");
return (EINVAL);
}
/*
* The recovery function is responsible for returning the LSN of the
* previous log record in this transaction, so that transaction aborts
* can follow the chain backwards.
*
* (If we'd wanted the LSN of this record earlier, we could have
* read it from lsnp, as well--but because we weren't working with
* pages or other objects that store their LSN and base recovery
* decisions on it, we didn't need to.)
*/
*lsnp = argp->prev_lsn;
out: if (argp != NULL)
free(argp);
return (ret);
}
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