1 | /* |
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2 | * MSDOS directory handlers implementation |
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3 | * |
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4 | * Copyright (C) 2001 OKTET Ltd., St.-Petersburg, Russia |
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5 | * Author: Eugeny S. Mints <Eugeny.Mints@oktet.ru> |
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6 | * |
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7 | * The license and distribution terms for this file may be |
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8 | * found in the file LICENSE in this distribution or at |
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9 | * http://www.OARcorp.com/rtems/license.html. |
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10 | * |
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11 | * @(#) $Id$ |
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12 | */ |
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13 | #if HAVE_CONFIG_H |
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14 | #include "config.h" |
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15 | #endif |
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16 | |
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17 | #include <stdlib.h> |
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18 | #include <unistd.h> |
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19 | #include <assert.h> |
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20 | #include <errno.h> |
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21 | #include <rtems/libio_.h> |
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22 | #include <sys/types.h> |
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23 | #include <sys/stat.h> |
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24 | |
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25 | #include <dirent.h> |
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26 | |
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27 | #include "fat.h" |
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28 | #include "fat_fat_operations.h" |
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29 | #include "fat_file.h" |
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30 | |
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31 | #include "msdos.h" |
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32 | |
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33 | /* msdos_dir_open -- |
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34 | * Open fat-file which correspondes to the directory being opened and |
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35 | * set offset field of file control block to zero. |
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36 | * |
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37 | * PARAMETERS: |
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38 | * iop - file control block |
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39 | * pathname - name |
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40 | * flag - flags |
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41 | * mode - mode |
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42 | * |
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43 | * RETURNS: |
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44 | * RC_OK, if directory opened successfully, or -1 if error occured (errno |
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45 | * set apropriately) |
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46 | */ |
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47 | int |
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48 | msdos_dir_open(rtems_libio_t *iop, const char *pathname, unsigned32 flag, |
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49 | unsigned32 mode) |
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50 | { |
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51 | int rc = RC_OK; |
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52 | rtems_status_code sc = RTEMS_SUCCESSFUL; |
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53 | msdos_fs_info_t *fs_info = iop->pathinfo.mt_entry->fs_info; |
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54 | fat_file_fd_t *fat_fd = iop->file_info; |
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55 | |
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56 | sc = rtems_semaphore_obtain(fs_info->vol_sema, RTEMS_WAIT, |
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57 | MSDOS_VOLUME_SEMAPHORE_TIMEOUT); |
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58 | if (sc != RTEMS_SUCCESSFUL) |
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59 | set_errno_and_return_minus_one( EIO ); |
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60 | |
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61 | rc = fat_file_reopen(fat_fd); |
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62 | if (rc != RC_OK) |
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63 | { |
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64 | rtems_semaphore_release(fs_info->vol_sema); |
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65 | return rc; |
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66 | } |
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67 | |
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68 | iop->offset = 0; |
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69 | rtems_semaphore_release(fs_info->vol_sema); |
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70 | return RC_OK; |
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71 | } |
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72 | |
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73 | /* msdos_dir_close -- |
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74 | * Close fat-file which correspondes to the directory being closed |
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75 | * |
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76 | * PARAMETERS: |
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77 | * iop - file control block |
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78 | * |
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79 | * RETURNS: |
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80 | * RC_OK, if directory closed successfully, or -1 if error occured (errno |
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81 | * set apropriately. |
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82 | */ |
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83 | int |
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84 | msdos_dir_close(rtems_libio_t *iop) |
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85 | { |
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86 | int rc = RC_OK; |
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87 | rtems_status_code sc = RTEMS_SUCCESSFUL; |
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88 | msdos_fs_info_t *fs_info = iop->pathinfo.mt_entry->fs_info; |
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89 | fat_file_fd_t *fat_fd = iop->file_info; |
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90 | |
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91 | sc = rtems_semaphore_obtain(fs_info->vol_sema, RTEMS_WAIT, |
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92 | MSDOS_VOLUME_SEMAPHORE_TIMEOUT); |
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93 | if (sc != RTEMS_SUCCESSFUL) |
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94 | set_errno_and_return_minus_one( EIO ); |
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95 | |
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96 | rc = fat_file_close(iop->pathinfo.mt_entry, fat_fd); |
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97 | if (rc != RC_OK) |
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98 | { |
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99 | rtems_semaphore_release(fs_info->vol_sema); |
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100 | return rc; |
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101 | } |
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102 | |
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103 | rtems_semaphore_release(fs_info->vol_sema); |
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104 | return RC_OK; |
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105 | } |
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106 | |
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107 | /* msdos_dir_read -- |
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108 | * This routine will read the next directory entry based on the directory |
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109 | * offset. The offset should be equal to -n- time the size of an |
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110 | * individual dirent structure. If n is not an integer multiple of the |
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111 | * sizeof a dirent structure, an integer division will be performed to |
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112 | * determine directory entry that will be returned in the buffer. Count |
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113 | * should reflect -m- times the sizeof dirent bytes to be placed in the |
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114 | * buffer. |
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115 | * If there are not -m- dirent elements from the current directory |
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116 | * position to the end of the exisiting file, the remaining entries will |
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117 | * be placed in the buffer and the returned value will be equal to |
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118 | * -m actual- times the size of a directory entry. |
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119 | * |
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120 | * PARAMETERS: |
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121 | * iop - file control block |
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122 | * buffer - buffer provided by user |
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123 | * count - count of bytes to read |
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124 | * |
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125 | * RETURNS: |
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126 | * the number of bytes read on success, or -1 if error occured (errno |
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127 | * set apropriately). |
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128 | */ |
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129 | ssize_t |
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130 | msdos_dir_read(rtems_libio_t *iop, void *buffer, unsigned32 count) |
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131 | { |
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132 | int rc = RC_OK; |
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133 | rtems_status_code sc = RTEMS_SUCCESSFUL; |
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134 | msdos_fs_info_t *fs_info = iop->pathinfo.mt_entry->fs_info; |
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135 | fat_file_fd_t *fat_fd = iop->file_info; |
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136 | fat_file_fd_t *tmp_fat_fd = NULL; |
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137 | struct dirent tmp_dirent; |
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138 | unsigned32 start = 0; |
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139 | ssize_t ret = 0; |
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140 | unsigned32 cmpltd = 0; |
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141 | unsigned32 j = 0, i = 0; |
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142 | unsigned32 bts2rd = 0; |
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143 | unsigned32 cur_cln = 0; |
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144 | |
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145 | /* |
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146 | * cast start and count - protect against using sizes that are not exact |
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147 | * multiples of the -dirent- size. These could result in unexpected |
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148 | * results |
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149 | */ |
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150 | start = iop->offset / sizeof(struct dirent); |
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151 | count = (count / sizeof(struct dirent)) * sizeof(struct dirent); |
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152 | |
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153 | /* |
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154 | * optimization: we know that root directory for FAT12/16 volumes is |
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155 | * sequential set of sectors and any cluster is sequential set of sectors |
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156 | * too, so read such set of sectors is quick operation for low-level IO |
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157 | * layer. |
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158 | */ |
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159 | bts2rd = (FAT_FD_OF_ROOT_DIR(fat_fd) && |
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160 | (fs_info->fat.vol.type & (FAT_FAT12 | FAT_FAT16))) ? |
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161 | fat_fd->fat_file_size : |
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162 | fs_info->fat.vol.bpc; |
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163 | |
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164 | sc = rtems_semaphore_obtain(fs_info->vol_sema, RTEMS_WAIT, |
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165 | MSDOS_VOLUME_SEMAPHORE_TIMEOUT); |
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166 | if (sc != RTEMS_SUCCESSFUL) |
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167 | set_errno_and_return_minus_one(EIO); |
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168 | |
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169 | while (count > 0) |
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170 | { |
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171 | /* |
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172 | * fat-file is already opened by open call, so read it |
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173 | * Always read directory fat-file from the beggining because of MSDOS |
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174 | * directories feature :( - we should count elements currently |
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175 | * present in the directory because there may be holes :) |
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176 | */ |
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177 | ret = fat_file_read(iop->pathinfo.mt_entry, fat_fd, (j * bts2rd), |
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178 | bts2rd, fs_info->cl_buf); |
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179 | if (ret < MSDOS_DIRECTORY_ENTRY_STRUCT_SIZE) |
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180 | { |
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181 | rtems_semaphore_release(fs_info->vol_sema); |
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182 | set_errno_and_return_minus_one(EIO); |
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183 | } |
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184 | |
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185 | for (i = 0; i < ret; i += MSDOS_DIRECTORY_ENTRY_STRUCT_SIZE) |
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186 | { |
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187 | if ((*MSDOS_DIR_NAME(fs_info->cl_buf + i)) == |
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188 | MSDOS_THIS_DIR_ENTRY_AND_REST_EMPTY) |
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189 | { |
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190 | rtems_semaphore_release(fs_info->vol_sema); |
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191 | return cmpltd; |
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192 | } |
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193 | |
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194 | if ((*MSDOS_DIR_NAME(fs_info->cl_buf + i)) == |
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195 | MSDOS_THIS_DIR_ENTRY_EMPTY) |
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196 | continue; |
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197 | |
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198 | /* |
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199 | * skip active entries until get the entry to start from |
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200 | */ |
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201 | if (start) |
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202 | { |
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203 | start--; |
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204 | continue; |
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205 | } |
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206 | |
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207 | /* |
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208 | * Move the entry to the return buffer |
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209 | * |
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210 | * unfortunately there is no method to extract ino except to |
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211 | * open fat-file descriptor :( ... so, open it |
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212 | */ |
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213 | |
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214 | /* get number of cluster we are working with */ |
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215 | rc = fat_file_ioctl(iop->pathinfo.mt_entry, fat_fd, F_CLU_NUM, |
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216 | j * bts2rd, &cur_cln); |
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217 | if (rc != RC_OK) |
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218 | { |
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219 | rtems_semaphore_release(fs_info->vol_sema); |
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220 | return rc; |
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221 | } |
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222 | |
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223 | rc = fat_file_open(iop->pathinfo.mt_entry, cur_cln, i, |
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224 | &tmp_fat_fd); |
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225 | if (rc != RC_OK) |
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226 | { |
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227 | rtems_semaphore_release(fs_info->vol_sema); |
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228 | return rc; |
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229 | } |
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230 | |
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231 | tmp_fat_fd->info_cln = cur_cln; |
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232 | tmp_fat_fd->info_ofs = i; |
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233 | |
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234 | /* fill in dirent structure */ |
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235 | /* XXX: from what and in what d_off should be computed ?! */ |
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236 | tmp_dirent.d_off = start + cmpltd; |
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237 | tmp_dirent.d_reclen = sizeof(struct dirent); |
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238 | tmp_dirent.d_ino = tmp_fat_fd->ino; |
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239 | tmp_dirent.d_namlen = MSDOS_SHORT_NAME_LEN; |
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240 | memcpy(tmp_dirent.d_name, MSDOS_DIR_NAME((fs_info->cl_buf + i)), |
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241 | MSDOS_SHORT_NAME_LEN); |
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242 | |
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243 | /* d_name is null-terminated */ |
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244 | tmp_dirent.d_name[MSDOS_SHORT_NAME_LEN] = 0; |
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245 | memcpy(buffer + cmpltd, &tmp_dirent, sizeof(struct dirent)); |
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246 | |
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247 | iop->offset = iop->offset + sizeof(struct dirent); |
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248 | cmpltd += (sizeof(struct dirent)); |
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249 | count -= (sizeof(struct dirent)); |
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250 | |
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251 | /* inode number extracted, close fat-file */ |
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252 | rc = fat_file_close(iop->pathinfo.mt_entry, tmp_fat_fd); |
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253 | if (rc != RC_OK) |
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254 | { |
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255 | rtems_semaphore_release(fs_info->vol_sema); |
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256 | return rc; |
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257 | } |
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258 | |
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259 | if (count <= 0) |
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260 | break; |
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261 | } |
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262 | j++; |
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263 | } |
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264 | |
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265 | rtems_semaphore_release(fs_info->vol_sema); |
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266 | return cmpltd; |
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267 | } |
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268 | |
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269 | /* msdos_dir_write -- |
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270 | * no write for directory |
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271 | */ |
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272 | |
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273 | /* msdos_dir_lseek -- |
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274 | * |
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275 | * This routine will behave in one of three ways based on the state of |
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276 | * argument whence. Based on the state of its value the offset argument will |
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277 | * be interpreted using one of the following methods: |
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278 | * |
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279 | * SEEK_SET - offset is the absolute byte offset from the start of the |
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280 | * logical start of the dirent sequence that represents the |
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281 | * directory |
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282 | * SEEK_CUR - offset is used as the relative byte offset from the current |
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283 | * directory position index held in the iop structure |
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284 | * SEEK_END - N/A --> This will cause an assert. |
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285 | * |
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286 | * PARAMETERS: |
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287 | * iop - file control block |
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288 | * offset - offset |
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289 | * whence - predefine directive |
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290 | * |
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291 | * RETURNS: |
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292 | * RC_OK on success, or -1 if error occured (errno |
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293 | * set apropriately). |
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294 | */ |
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295 | int |
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296 | msdos_dir_lseek(rtems_libio_t *iop, off_t offset, int whence) |
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297 | { |
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298 | switch (whence) |
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299 | { |
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300 | case SEEK_SET: |
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301 | case SEEK_CUR: |
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302 | break; |
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303 | /* |
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304 | * Movement past the end of the directory via lseek is not a |
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305 | * permitted operation |
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306 | */ |
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307 | case SEEK_END: |
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308 | default: |
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309 | set_errno_and_return_minus_one( EINVAL ); |
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310 | break; |
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311 | } |
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312 | return RC_OK; |
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313 | } |
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314 | |
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315 | /* msdos_dir_stat -- |
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316 | * |
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317 | * This routine will obtain the following information concerning the current |
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318 | * directory: |
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319 | * st_dev device id |
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320 | * st_ino node serial number :) |
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321 | * st_mode mode extracted from the node |
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322 | * st_size total size in bytes |
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323 | * st_blksize blocksize for filesystem I/O |
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324 | * st_blocks number of blocks allocated |
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325 | * stat_mtime time of last modification |
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326 | * |
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327 | * PARAMETERS: |
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328 | * loc - this directory |
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329 | * buf - stat buffer provided by user |
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330 | * |
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331 | * RETURNS: |
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332 | * RC_OK and filled stat buffer on success, or -1 if error occured (errno |
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333 | * set apropriately). |
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334 | */ |
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335 | int |
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336 | msdos_dir_stat( |
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337 | rtems_filesystem_location_info_t *loc, |
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338 | struct stat *buf |
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339 | ) |
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340 | { |
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341 | rtems_status_code sc = RTEMS_SUCCESSFUL; |
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342 | msdos_fs_info_t *fs_info = loc->mt_entry->fs_info; |
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343 | fat_file_fd_t *fat_fd = loc->node_access; |
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344 | |
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345 | sc = rtems_semaphore_obtain(fs_info->vol_sema, RTEMS_WAIT, |
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346 | MSDOS_VOLUME_SEMAPHORE_TIMEOUT); |
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347 | if (sc != RTEMS_SUCCESSFUL) |
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348 | set_errno_and_return_minus_one(EIO); |
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349 | |
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350 | buf->st_dev = fs_info->fat.vol.dev; |
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351 | buf->st_ino = fat_fd->ino; |
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352 | buf->st_mode = S_IFDIR; |
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353 | buf->st_rdev = 0ll; |
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354 | buf->st_size = fat_fd->fat_file_size; |
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355 | buf->st_blocks = fat_fd->fat_file_size >> FAT_SECTOR512_BITS; |
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356 | buf->st_blksize = fs_info->fat.vol.bps; |
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357 | buf->st_mtime = fat_fd->mtime; |
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358 | |
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359 | rtems_semaphore_release(fs_info->vol_sema); |
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360 | return RC_OK; |
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361 | } |
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362 | |
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363 | /* msdos_dir_truncate -- |
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364 | * No truncate for directory. |
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365 | * |
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366 | * PARAMETERS: |
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367 | * |
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368 | * RETURNS: |
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369 | * |
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370 | */ |
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371 | |
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372 | /* msdos_dir_sync -- |
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373 | * The following routine does a syncronization on a MSDOS directory node. |
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374 | * DIR_WrtTime, DIR_WrtDate and DIR_fileSize fields of 32 Bytes Directory |
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375 | * Entry Structure(see M$ White Paper) should not be updated for |
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376 | * directories, so only call to corresponding fat-file routine. |
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377 | * |
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378 | * PARAMETERS: |
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379 | * iop - file control block |
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380 | * |
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381 | * RETURNS: |
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382 | * RC_OK on success, or -1 if error occured (errno set apropriately). |
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383 | */ |
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384 | int |
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385 | msdos_dir_sync(rtems_libio_t *iop) |
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386 | { |
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387 | int rc = RC_OK; |
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388 | rtems_status_code sc = RTEMS_SUCCESSFUL; |
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389 | fat_file_fd_t *fat_fd = iop->file_info; |
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390 | msdos_fs_info_t *fs_info = iop->pathinfo.mt_entry->fs_info; |
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391 | |
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392 | sc = rtems_semaphore_obtain(fs_info->vol_sema, RTEMS_WAIT, |
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393 | MSDOS_VOLUME_SEMAPHORE_TIMEOUT); |
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394 | if (sc != RTEMS_SUCCESSFUL) |
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395 | set_errno_and_return_minus_one(EIO); |
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396 | |
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397 | rc = fat_file_datasync(iop->pathinfo.mt_entry, fat_fd); |
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398 | |
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399 | rtems_semaphore_release(fs_info->vol_sema); |
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400 | return rc; |
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401 | } |
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402 | |
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403 | /* msdos_dir_rmnod -- |
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404 | * Remove directory node. |
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405 | * |
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406 | * Check that this directory node is not opened as fat-file, is empty and |
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407 | * not filesystem root node. If all this conditions met then delete. |
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408 | * |
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409 | * PARAMETERS: |
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410 | * pathloc - node description |
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411 | * |
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412 | * RETURNS: |
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413 | * RC_OK on success, or -1 if error occured (errno set apropriately). |
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414 | */ |
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415 | int |
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416 | msdos_dir_rmnod(rtems_filesystem_location_info_t *pathloc) |
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417 | { |
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418 | int rc = RC_OK; |
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419 | rtems_status_code sc = RTEMS_SUCCESSFUL; |
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420 | msdos_fs_info_t *fs_info = pathloc->mt_entry->fs_info; |
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421 | fat_file_fd_t *fat_fd = pathloc->node_access; |
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422 | rtems_boolean is_empty = FALSE; |
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423 | |
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424 | sc = rtems_semaphore_obtain(fs_info->vol_sema, RTEMS_WAIT, |
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425 | MSDOS_VOLUME_SEMAPHORE_TIMEOUT); |
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426 | if (sc != RTEMS_SUCCESSFUL) |
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427 | set_errno_and_return_minus_one(EIO); |
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428 | |
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429 | /* |
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430 | * We deny attemp to delete open directory (if directory is current |
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431 | * directory we assume it is open one) |
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432 | */ |
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433 | if (fat_fd->links_num > 1) |
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434 | { |
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435 | rtems_semaphore_release(fs_info->vol_sema); |
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436 | set_errno_and_return_minus_one(EBUSY); |
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437 | } |
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438 | |
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439 | /* |
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440 | * You cannot remove a node that still has children |
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441 | */ |
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442 | rc = msdos_dir_is_empty(pathloc->mt_entry, fat_fd, &is_empty); |
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443 | if (rc != RC_OK) |
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444 | { |
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445 | rtems_semaphore_release(fs_info->vol_sema); |
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446 | return rc; |
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447 | } |
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448 | |
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449 | if (!is_empty) |
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450 | { |
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451 | rtems_semaphore_release(fs_info->vol_sema); |
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452 | set_errno_and_return_minus_one(ENOTEMPTY); |
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453 | } |
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454 | |
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455 | /* |
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456 | * You cannot remove the file system root node. |
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457 | */ |
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458 | if (pathloc->mt_entry->mt_fs_root.node_access == pathloc->node_access) |
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459 | { |
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460 | rtems_semaphore_release(fs_info->vol_sema); |
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461 | set_errno_and_return_minus_one(EBUSY); |
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462 | } |
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463 | |
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464 | /* |
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465 | * You cannot remove a mountpoint. |
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466 | * not used - mount() not implemenetd yet. |
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467 | */ |
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468 | |
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469 | /* mark file removed */ |
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470 | rc = msdos_set_first_char4file_name(pathloc->mt_entry, fat_fd->info_cln, |
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471 | fat_fd->info_ofs, |
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472 | MSDOS_THIS_DIR_ENTRY_EMPTY); |
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473 | if (rc != RC_OK) |
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474 | { |
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475 | rtems_semaphore_release(fs_info->vol_sema); |
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476 | return rc; |
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477 | } |
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478 | |
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479 | fat_file_mark_removed(pathloc->mt_entry, fat_fd); |
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480 | |
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481 | rtems_semaphore_release(fs_info->vol_sema); |
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482 | return rc; |
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483 | } |
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