| 1 | /* dbminit.c - Open the file for dbm operations. This looks like the
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| 2 | DBM interface. */
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| 3 |
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| 4 | /* This file is part of GDBM, the GNU data base manager, by Philip A. Nelson.
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| 5 | Copyright (C) 1990, 1991, 1993 Free Software Foundation, Inc.
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| 6 |
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| 7 | GDBM is free software; you can redistribute it and/or modify
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| 8 | it under the terms of the GNU General Public License as published by
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| 9 | the Free Software Foundation; either version 2, or (at your option)
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| 10 | any later version.
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| 11 |
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| 12 | GDBM is distributed in the hope that it will be useful,
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| 13 | but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 15 | GNU General Public License for more details.
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| 16 |
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| 17 | You should have received a copy of the GNU General Public License
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| 18 | along with GDBM; see the file COPYING. If not, write to
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| 19 | the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
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| 20 |
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| 21 | You may contact the author by:
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| 22 | e-mail: [email protected]
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| 23 | us-mail: Philip A. Nelson
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| 24 | Computer Science Department
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| 25 | Western Washington University
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| 26 | Bellingham, WA 98226
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| 27 |
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| 28 | *************************************************************************/
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| 29 |
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| 30 |
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| 31 | /* include system configuration before all else. */
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| 32 | #include "autoconf.h"
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| 33 |
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| 34 | #include "gdbmdefs.h"
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| 35 | #include "gdbmerrno.h"
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| 36 | #include "extern.h"
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| 37 |
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| 38 | /* Initialize dbm system. FILE is a pointer to the file name. In
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| 39 | standard dbm, the database is found in files called FILE.pag and
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| 40 | FILE.dir. To make gdbm compatable with dbm using the dbminit call,
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| 41 | the same file names are used. Specifically, dbminit will use the file
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| 42 | name FILE.pag in its call to gdbm open. If the file (FILE.pag) has a
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| 43 | size of zero bytes, a file initialization procedure is performed,
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| 44 | setting up the initial structure in the file. Any error detected will
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| 45 | cause a return value of -1. No errors cause the return value of 0.
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| 46 | NOTE: file.dir will be linked to file.pag. */
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| 47 |
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| 48 | int
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| 49 | dbminit (file)
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| 50 | char *file;
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| 51 | {
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| 52 | char* pag_file; /* Used to construct "file.pag". */
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| 53 | char* dir_file; /* Used to construct "file.dir". */
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| 54 | struct stat dir_stat; /* Stat information for "file.dir". */
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| 55 | int ret;
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| 56 |
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| 57 |
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| 58 | ret = 0; /* Default return value. */
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| 59 |
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| 60 | /* Prepare the correct names of "file.pag" and "file.dir". */
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| 61 | pag_file = (char *) malloc (strlen (file)+5);
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| 62 | dir_file = (char *) malloc (strlen (file)+5);
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| 63 | if ((pag_file == NULL) || (dir_file == NULL))
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| 64 | {
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| 65 | gdbm_errno = GDBM_MALLOC_ERROR; /* For the hell of it. */
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| 66 | return -1;
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| 67 | }
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| 68 |
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| 69 | strcpy (pag_file, file);
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| 70 | strcat (pag_file, ".pag");
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| 71 | strcpy (dir_file, file);
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| 72 | strcat (dir_file, ".dir");
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| 73 |
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| 74 | if (_gdbm_file != NULL)
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| 75 | gdbm_close (_gdbm_file);
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| 76 |
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| 77 | /* Try to open the file as a writer. DBM never created a file. */
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| 78 | #ifdef MSDOS
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| 79 | /* Not clear if final argument for Windows should be to obtain a
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| 80 | file lock or not. Play it safe for now and ask for a lock
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| 81 | */
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| 82 | _gdbm_file = gdbm_open (pag_file, 0, GDBM_WRITER, 0, NULL, TRUE);
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| 83 | #else
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| 84 | _gdbm_file = gdbm_open (pag_file, 0, GDBM_WRITER, 0, NULL);
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| 85 | #endif
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| 86 |
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| 87 | /* If it was not opened, try opening it as a reader. */
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| 88 | if (_gdbm_file == NULL)
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| 89 | {
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| 90 | #ifdef MSDOS
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| 91 | _gdbm_file = gdbm_open (pag_file, 0, GDBM_READER, 0, NULL, TRUE);
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| 92 | #else
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| 93 | _gdbm_file = gdbm_open (pag_file, 0, GDBM_READER, 0, NULL);
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| 94 | #endif
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| 95 | /* Did we successfully open the file? */
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| 96 | if (_gdbm_file == NULL)
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| 97 | {
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| 98 | gdbm_errno = GDBM_FILE_OPEN_ERROR;
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| 99 | ret = -1;
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| 100 | goto done;
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| 101 | }
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| 102 | }
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| 103 |
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| 104 | /* If the database is new, link "file.dir" to "file.pag". This is done
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| 105 | so the time stamp on both files is the same. */
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| 106 | if (stat (dir_file, &dir_stat) == 0)
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| 107 | {
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| 108 | if (dir_stat.st_size == 0)
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| 109 | if (unlink (dir_file) != 0 || link (pag_file, dir_file) != 0)
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| 110 | {
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| 111 | gdbm_errno = GDBM_FILE_OPEN_ERROR;
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| 112 | gdbm_close (_gdbm_file);
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| 113 | ret = -1;
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| 114 | goto done;
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| 115 | }
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| 116 | }
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| 117 | else
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| 118 | {
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| 119 | /* Since we can't stat it, we assume it is not there and try
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| 120 | to link the dir_file to the pag_file. */
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| 121 | if (link (pag_file, dir_file) != 0)
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| 122 | {
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| 123 | gdbm_errno = GDBM_FILE_OPEN_ERROR;
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| 124 | gdbm_close (_gdbm_file);
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| 125 | ret = -1;
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| 126 | goto done;
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| 127 | }
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| 128 | }
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| 129 |
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| 130 | ret = 0;
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| 131 |
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| 132 | done:
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| 133 | free (dir_file);
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| 134 | free (pag_file);
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| 135 | return ret;
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| 136 | }
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