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/* dbminit.c - Open the file for dbm operations. This looks like the
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/* This file is part of GDBM, the GNU data base manager, by Philip A. Nelson.
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Copyright (C) 1990, 1991, 1993 Free Software Foundation, Inc.
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GDBM is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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GDBM is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GDBM; see the file COPYING. If not, write to
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the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
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You may contact the author by:
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e-mail: phil@cs.wwu.edu
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us-mail: Philip A. Nelson
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Computer Science Department
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Western Washington University
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*************************************************************************/
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/* AIX demands this be the very first thing in the file. */
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#if !defined(__GNUC__) && defined(_AIX)
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/* include system configuration before all else. */
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#include "gdbmerrno.h"
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/* Initialize dbm system. FILE is a pointer to the file name. In
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standard dbm, the database is found in files called FILE.pag and
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FILE.dir. To make gdbm compatable with dbm using the dbminit call,
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the same file names are used. Specifically, dbminit will use the file
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name FILE.pag in its call to gdbm open. If the file (FILE.pag) has a
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size of zero bytes, a file initialization procedure is performed,
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setting up the initial structure in the file. Any error detected will
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cause a return value of -1. No errors cause the return value of 0.
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NOTE: file.dir will be linked to file.pag. */
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char* pag_file; /* Used to construct "file.pag". */
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char* dir_file; /* Used to construct "file.dir". */
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struct stat dir_stat; /* Stat information for "file.dir". */
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/* Prepare the correct names of "file.pag" and "file.dir". */
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pag_file = (char *) alloca (strlen (file)+5);
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dir_file = (char *) alloca (strlen (file)+5);
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strcpy (pag_file, file);
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strcat (pag_file, ".pag");
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strcpy (dir_file, file);
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strcat (dir_file, ".dir");
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if (_gdbm_file != NULL)
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gdbm_close (_gdbm_file);
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/* Try to open the file as a writer. DBM never created a file. */
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_gdbm_file = gdbm_open (pag_file, 0, GDBM_WRITER, 0, NULL);
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/* If it was not opened, try opening it as a reader. */
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if (_gdbm_file == NULL)
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_gdbm_file = gdbm_open (pag_file, 0, GDBM_READER, 0, NULL);
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/* Did we successfully open the file? */
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if (_gdbm_file == NULL)
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gdbm_errno = GDBM_FILE_OPEN_ERROR;
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/* If the database is new, link "file.dir" to "file.pag". This is done
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so the time stamp on both files is the same. */
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if (stat (dir_file, &dir_stat) == 0)
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if (dir_stat.st_size == 0)
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if (unlink (dir_file) != 0 || link (pag_file, dir_file) != 0)
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gdbm_errno = GDBM_FILE_OPEN_ERROR;
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gdbm_close (_gdbm_file);
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/* Since we can't stat it, we assume it is not there and try
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to link the dir_file to the pag_file. */
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if (link (pag_file, dir_file) != 0)
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gdbm_errno = GDBM_FILE_OPEN_ERROR;
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gdbm_close (_gdbm_file);
added
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dbminit.c
