1/* update.c - The routines for updating the file to a consistent state. */ 2 3/* This file is part of GDBM, the GNU data base manager, by Philip A. Nelson. 4 Copyright (C) 1990, 1991, 1993 Free Software Foundation, Inc. 5 6 GDBM is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 2, or (at your option) 9 any later version. 10 11 GDBM is distributed in the hope that it will be useful, 12 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 GNU General Public License for more details. 15 16 You should have received a copy of the GNU General Public License 17 along with GDBM; see the file COPYING. If not, write to 18 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. 19 20 You may contact the author by: 21 e-mail: phil@cs.wwu.edu 22 us-mail: Philip A. Nelson 23 Computer Science Department 24 Western Washington University 25 Bellingham, WA 98226 26 27*************************************************************************/ 28 29 30/* include system configuration before all else. */ 31#include "autoconf.h" 32 33#include "gdbmdefs.h" 34 35static void write_header __P((gdbm_file_info *)); 36 37/* This procedure writes the header back to the file described by DBF. */ 38 39static void 40write_header (dbf) 41 gdbm_file_info *dbf; 42{ 43 int num_bytes; /* Return value for write. */ 44 off_t file_pos; /* Return value for lseek. */ 45 46 file_pos = lseek (dbf->desc, 0L, L_SET); 47 if (file_pos != 0) _gdbm_fatal (dbf, "lseek error"); 48 num_bytes = write (dbf->desc, dbf->header, dbf->header->block_size); 49 if (num_bytes != dbf->header->block_size) 50 _gdbm_fatal (dbf, "write error"); 51 52 /* Wait for all output to be done. */ 53 if (!dbf->fast_write) 54 fsync (dbf->desc); 55} 56 57 58/* After all changes have been made in memory, we now write them 59 all to disk. */ 60void 61_gdbm_end_update (dbf) 62 gdbm_file_info *dbf; 63{ 64 int num_bytes; /* Return value for write. */ 65 off_t file_pos; /* Return value for lseek. */ 66 67 68 /* Write the current bucket. */ 69 if (dbf->bucket_changed && (dbf->cache_entry != NULL)) 70 { 71 _gdbm_write_bucket (dbf, dbf->cache_entry); 72 dbf->bucket_changed = FALSE; 73 } 74 75 /* Write the other changed buckets if there are any. */ 76 if (dbf->second_changed) 77 { 78 if(dbf->bucket_cache != NULL) 79 { 80 register int index; 81 82 for (index = 0; index < dbf->cache_size; index++) 83 { 84 if (dbf->bucket_cache[index].ca_changed) 85 _gdbm_write_bucket (dbf, &dbf->bucket_cache[index]); 86 } 87 } 88 dbf->second_changed = FALSE; 89 } 90 91 /* Write the directory. */ 92 if (dbf->directory_changed) 93 { 94 file_pos = lseek (dbf->desc, dbf->header->dir, L_SET); 95 if (file_pos != dbf->header->dir) _gdbm_fatal (dbf, "lseek error"); 96 num_bytes = write (dbf->desc, dbf->dir, dbf->header->dir_size); 97 if (num_bytes != dbf->header->dir_size) 98 _gdbm_fatal (dbf, "write error"); 99 dbf->directory_changed = FALSE; 100 if (!dbf->header_changed && !dbf->fast_write) 101 fsync (dbf->desc); 102 } 103 104 /* Final write of the header. */ 105 if (dbf->header_changed) 106 { 107 write_header (dbf); 108 dbf->header_changed = FALSE; 109 } 110} 111 112 113/* If a fatal error is detected, come here and exit. VAL tells which fatal 114 error occured. */ 115 116void 117_gdbm_fatal (dbf, val) 118 gdbm_file_info *dbf; 119 char *val; 120{ 121 if ((dbf != NULL) && (dbf->fatal_err != NULL)) 122 (*dbf->fatal_err) (val); 123 else 124 { 125 write (STDERR_FILENO, "gdbm fatal: ", 12); 126 if (val != NULL) 127 write (STDERR_FILENO, val, strlen(val)); 128 write (STDERR_FILENO, "\n", 1); 129 } 130 exit (1); 131 /* NOTREACHED */ 132} 133