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