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gdbmreorg.c
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C/C++ Source or Header
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1993-11-13
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6KB
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218 lines
/* gdbmreorg.c - Reorganize the database file. */
/* This file is part of GDBM, the GNU data base manager, by Philip A. Nelson.
Copyright (C) 1990, 1991, 1993 Free Software Foundation, Inc.
GDBM is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
GDBM is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with GDBM; see the file COPYING. If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
You may contact the author by:
e-mail: phil@cs.wwu.edu
us-mail: Philip A. Nelson
Computer Science Department
Western Washington University
Bellingham, WA 98226
************************************************************************/
/* AIX demands this be the very first thing in the file. */
#if !defined(__GNUC__) && defined(_AIX)
#pragma alloca
#endif
/* include system configuration before all else. */
#include "autoconf.h"
#include "gdbmdefs.h"
#include "gdbmerrno.h"
#include "extern.h"
#if !HAVE_RENAME
/* Rename takes OLD_NAME and renames it as NEW_NAME. If it can not rename
the file a non-zero value is returned. OLD_NAME is guaranteed to
remain if it can't be renamed. It assumes NEW_NAME always exists (due
to being used in gdbm). */
static int
rename (old_name, new_name)
char* old_name;
char* new_name;
{
if (unlink (new_name) != 0)
return -1;
if (link (old_name, new_name) != 0)
return -1;
unlink (old_name);
return 0;
}
#endif
/* Reorganize the database. This requires creating a new file and inserting
all the elements in the old file DBF into the new file. The new file
is then renamed to the same name as the old file and DBF is updated to
contain all the correct information about the new file. If an error
is detected, the return value is negative. The value zero is returned
after a successful reorganization. */
int
gdbm_reorganize (dbf)
gdbm_file_info *dbf;
{
gdbm_file_info *new_dbf; /* The new file. */
char *new_name; /* A temporary name. */
int len; /* Used in new_name construction. */
datum key, nextkey, data; /* For the sequential sweep. */
struct stat fileinfo; /* Information about the file. */
int index; /* Use in moving the bucket cache. */
/* Readers can not reorganize! */
if (dbf->read_write == GDBM_READER)
{
gdbm_errno = GDBM_READER_CANT_REORGANIZE;
return -1;
}
/* Initialize the gdbm_errno variable. */
gdbm_errno = GDBM_NO_ERROR;
/* Construct new name for temporary file. */
len = strlen (dbf->name);
new_name = (char *) alloca (len + 3);
if (new_name == NULL)
{
gdbm_errno = GDBM_MALLOC_ERROR;
return -1;
}
strcpy (&new_name[0], dbf->name);
new_name[len+2] = 0;
new_name[len+1] = '#';
while ( (len > 0) && new_name[len-1] != '/')
{
new_name[len] = new_name[len-1];
len -= 1;
}
new_name[len] = '#';
/* Get the mode for the old file and open the new database.
The "fast" mode is used because the reorganization will fail
unless we create a complete copy of the database. */
fstat (dbf->desc, &fileinfo);
new_dbf = gdbm_open (new_name, dbf->header->block_size,
GDBM_WRCREAT | GDBM_FAST,
fileinfo.st_mode, dbf->fatal_err);
if (new_dbf == NULL)
{
gdbm_errno = GDBM_REORGANIZE_FAILED;
return -1;
}
/* For each item in the old database, add an entry in the new. */
key = gdbm_firstkey (dbf);
while (key.dptr != NULL)
{
data = gdbm_fetch (dbf, key);
if (data.dptr != NULL)
{
/* Add the data to the new file. */
if (gdbm_store (new_dbf, key, data, GDBM_INSERT) != 0)
{
gdbm_close (new_dbf);
gdbm_errno = GDBM_REORGANIZE_FAILED;
unlink (new_name);
return -1;
};
}
else
{
/* ERROR! Abort and don't finish reorganize. */
gdbm_close (new_dbf);
gdbm_errno = GDBM_REORGANIZE_FAILED;
unlink (new_name);
return -1;
}
nextkey = gdbm_nextkey (dbf, key);
free (key.dptr);
free (data.dptr);
key = nextkey;
}
/* Write everything. */
_gdbm_end_update (new_dbf);
gdbm_sync (new_dbf);
/* Move the new file to old name. */
if (rename (new_name, dbf->name) != 0)
{
gdbm_errno = GDBM_REORGANIZE_FAILED;
gdbm_close (new_dbf);
return -1;
}
/* Fix up DBF to have the correct information for the new file. */
UNLOCK_FILE(dbf);
close (dbf->desc);
free (dbf->header);
free (dbf->dir);
if (dbf->bucket_cache != NULL) {
for (index = 0; index < dbf->cache_size; index++) {
if (dbf->bucket_cache[index].ca_bucket != NULL)
free (dbf->bucket_cache[index].ca_bucket);
if (dbf->bucket_cache[index].ca_data.dptr != NULL)
free (dbf->bucket_cache[index].ca_data.dptr);
}
free (dbf->bucket_cache);
}
dbf->desc = new_dbf->desc;
dbf->header = new_dbf->header;
dbf->dir = new_dbf->dir;
dbf->bucket = new_dbf->bucket;
dbf->bucket_dir = new_dbf->bucket_dir;
dbf->last_read = new_dbf->last_read;
dbf->bucket_cache = new_dbf->bucket_cache;
dbf->cache_size = new_dbf->cache_size;
dbf->header_changed = new_dbf->header_changed;
dbf->directory_changed = new_dbf->directory_changed;
dbf->bucket_changed = new_dbf->bucket_changed;
dbf->second_changed = new_dbf->second_changed;
free (new_dbf);
/* Make sure the new database is all on disk. */
fsync (dbf->desc);
/* Force the right stuff for a correct bucket cache. */
dbf->cache_entry = &dbf->bucket_cache[0];
_gdbm_get_bucket (dbf, 0);
return 0;
}