1 | /** |
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2 | * @file |
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3 | * |
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4 | * @brief IMFS Memory File Handlers |
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5 | * @ingroup IMFS |
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6 | */ |
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7 | |
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8 | /* |
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9 | * COPYRIGHT (c) 1989-2010. |
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10 | * On-Line Applications Research Corporation (OAR). |
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11 | * |
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12 | * The license and distribution terms for this file may be |
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13 | * found in the file LICENSE in this distribution or at |
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14 | * http://www.rtems.com/license/LICENSE. |
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15 | */ |
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16 | |
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17 | #if HAVE_CONFIG_H |
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18 | #include "config.h" |
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19 | #endif |
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20 | |
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21 | #include "imfs.h" |
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22 | |
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23 | #include <stdlib.h> |
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24 | #include <string.h> |
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25 | |
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26 | #define MEMFILE_STATIC |
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27 | |
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28 | /* |
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29 | * Prototypes of private routines |
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30 | */ |
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31 | MEMFILE_STATIC int IMFS_memfile_extend( |
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32 | IMFS_jnode_t *the_jnode, |
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33 | bool zero_fill, |
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34 | off_t new_length |
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35 | ); |
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36 | |
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37 | MEMFILE_STATIC int IMFS_memfile_addblock( |
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38 | IMFS_jnode_t *the_jnode, |
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39 | unsigned int block |
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40 | ); |
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41 | |
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42 | MEMFILE_STATIC int IMFS_memfile_remove_block( |
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43 | IMFS_jnode_t *the_jnode, |
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44 | unsigned int block |
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45 | ); |
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46 | |
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47 | MEMFILE_STATIC block_p *IMFS_memfile_get_block_pointer( |
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48 | IMFS_jnode_t *the_jnode, |
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49 | unsigned int block, |
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50 | int malloc_it |
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51 | ); |
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52 | |
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53 | MEMFILE_STATIC ssize_t IMFS_memfile_read( |
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54 | IMFS_jnode_t *the_jnode, |
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55 | off_t start, |
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56 | unsigned char *destination, |
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57 | unsigned int length |
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58 | ); |
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59 | |
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60 | ssize_t IMFS_memfile_write( /* cannot be static as used in imfs_fchmod.c */ |
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61 | IMFS_jnode_t *the_jnode, |
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62 | off_t start, |
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63 | const unsigned char *source, |
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64 | unsigned int length |
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65 | ); |
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66 | |
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67 | void *memfile_alloc_block(void); |
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68 | |
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69 | void memfile_free_block( |
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70 | void *memory |
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71 | ); |
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72 | |
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73 | int memfile_open( |
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74 | rtems_libio_t *iop, |
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75 | const char *pathname, |
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76 | int oflag, |
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77 | mode_t mode |
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78 | ) |
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79 | { |
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80 | IMFS_jnode_t *the_jnode; |
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81 | |
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82 | the_jnode = iop->pathinfo.node_access; |
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83 | |
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84 | /* |
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85 | * Perform 'copy on write' for linear files |
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86 | */ |
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87 | if ((iop->flags & LIBIO_FLAGS_WRITE) |
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88 | && (IMFS_type( the_jnode ) == IMFS_LINEAR_FILE)) { |
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89 | uint32_t count = the_jnode->info.linearfile.size; |
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90 | const unsigned char *buffer = the_jnode->info.linearfile.direct; |
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91 | |
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92 | the_jnode->control = &IMFS_node_control_memfile; |
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93 | the_jnode->info.file.size = 0; |
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94 | the_jnode->info.file.indirect = 0; |
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95 | the_jnode->info.file.doubly_indirect = 0; |
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96 | the_jnode->info.file.triply_indirect = 0; |
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97 | if ((count != 0) |
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98 | && (IMFS_memfile_write(the_jnode, 0, buffer, count) == -1)) |
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99 | return -1; |
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100 | } |
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101 | |
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102 | return 0; |
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103 | } |
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104 | |
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105 | ssize_t memfile_read( |
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106 | rtems_libio_t *iop, |
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107 | void *buffer, |
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108 | size_t count |
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109 | ) |
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110 | { |
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111 | IMFS_jnode_t *the_jnode; |
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112 | ssize_t status; |
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113 | |
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114 | the_jnode = iop->pathinfo.node_access; |
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115 | |
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116 | status = IMFS_memfile_read( the_jnode, iop->offset, buffer, count ); |
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117 | |
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118 | if ( status > 0 ) |
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119 | iop->offset += status; |
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120 | |
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121 | return status; |
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122 | } |
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123 | |
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124 | ssize_t memfile_write( |
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125 | rtems_libio_t *iop, |
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126 | const void *buffer, |
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127 | size_t count |
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128 | ) |
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129 | { |
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130 | IMFS_jnode_t *the_jnode; |
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131 | ssize_t status; |
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132 | |
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133 | the_jnode = iop->pathinfo.node_access; |
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134 | |
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135 | if ((iop->flags & LIBIO_FLAGS_APPEND) != 0) |
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136 | iop->offset = the_jnode->info.file.size; |
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137 | |
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138 | status = IMFS_memfile_write( the_jnode, iop->offset, buffer, count ); |
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139 | |
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140 | if ( status > 0 ) |
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141 | iop->offset += status; |
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142 | |
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143 | return status; |
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144 | } |
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145 | |
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146 | /* |
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147 | * memfile_stat |
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148 | * |
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149 | * This IMFS_stat() can be used. |
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150 | */ |
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151 | |
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152 | int memfile_ftruncate( |
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153 | rtems_libio_t *iop, |
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154 | off_t length |
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155 | ) |
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156 | { |
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157 | IMFS_jnode_t *the_jnode; |
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158 | |
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159 | the_jnode = iop->pathinfo.node_access; |
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160 | |
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161 | /* |
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162 | * POSIX 1003.1b does not specify what happens if you truncate a file |
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163 | * and the new length is greater than the current size. We treat this |
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164 | * as an extend operation. |
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165 | */ |
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166 | |
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167 | if ( length > the_jnode->info.file.size ) |
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168 | return IMFS_memfile_extend( the_jnode, true, length ); |
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169 | |
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170 | /* |
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171 | * The in-memory files do not currently reclaim memory until the file is |
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172 | * deleted. So we leave the previously allocated blocks in place for |
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173 | * future use and just set the length. |
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174 | */ |
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175 | the_jnode->info.file.size = length; |
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176 | |
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177 | IMFS_update_atime( the_jnode ); |
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178 | |
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179 | return 0; |
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180 | } |
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181 | |
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182 | /* |
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183 | * IMFS_memfile_extend |
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184 | * |
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185 | * This routine insures that the in-memory file is of the length |
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186 | * specified. If necessary, it will allocate memory blocks to |
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187 | * extend the file. |
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188 | */ |
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189 | MEMFILE_STATIC int IMFS_memfile_extend( |
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190 | IMFS_jnode_t *the_jnode, |
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191 | bool zero_fill, |
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192 | off_t new_length |
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193 | ) |
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194 | { |
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195 | unsigned int block; |
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196 | unsigned int new_blocks; |
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197 | unsigned int old_blocks; |
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198 | unsigned int offset; |
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199 | |
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200 | /* |
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201 | * Perform internal consistency checks |
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202 | */ |
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203 | IMFS_assert( the_jnode ); |
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204 | IMFS_assert( IMFS_type( the_jnode ) == IMFS_MEMORY_FILE ); |
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205 | |
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206 | /* |
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207 | * Verify new file size is supported |
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208 | */ |
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209 | if ( new_length >= IMFS_MEMFILE_MAXIMUM_SIZE ) |
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210 | rtems_set_errno_and_return_minus_one( EFBIG ); |
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211 | |
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212 | /* |
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213 | * Verify new file size is actually larger than current size |
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214 | */ |
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215 | if ( new_length <= the_jnode->info.file.size ) |
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216 | return 0; |
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217 | |
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218 | /* |
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219 | * Calculate the number of range of blocks to allocate |
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220 | */ |
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221 | new_blocks = new_length / IMFS_MEMFILE_BYTES_PER_BLOCK; |
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222 | old_blocks = the_jnode->info.file.size / IMFS_MEMFILE_BYTES_PER_BLOCK; |
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223 | offset = the_jnode->info.file.size - old_blocks * IMFS_MEMFILE_BYTES_PER_BLOCK; |
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224 | |
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225 | /* |
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226 | * Now allocate each of those blocks. |
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227 | */ |
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228 | for ( block=old_blocks ; block<=new_blocks ; block++ ) { |
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229 | if ( !IMFS_memfile_addblock( the_jnode, block ) ) { |
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230 | if ( zero_fill ) { |
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231 | size_t count = IMFS_MEMFILE_BYTES_PER_BLOCK - offset; |
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232 | block_p *block_ptr = |
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233 | IMFS_memfile_get_block_pointer( the_jnode, block, 0 ); |
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234 | |
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235 | memset( &(*block_ptr) [offset], 0, count); |
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236 | offset = 0; |
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237 | } |
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238 | } else { |
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239 | for ( ; block>=old_blocks ; block-- ) { |
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240 | IMFS_memfile_remove_block( the_jnode, block ); |
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241 | } |
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242 | rtems_set_errno_and_return_minus_one( ENOSPC ); |
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243 | } |
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244 | } |
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245 | |
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246 | /* |
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247 | * Set the new length of the file. |
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248 | */ |
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249 | the_jnode->info.file.size = new_length; |
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250 | |
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251 | IMFS_update_ctime(the_jnode); |
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252 | IMFS_update_mtime(the_jnode); |
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253 | return 0; |
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254 | } |
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255 | |
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256 | /* |
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257 | * IMFS_memfile_addblock |
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258 | * |
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259 | * This routine adds a single block to the specified in-memory file. |
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260 | */ |
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261 | MEMFILE_STATIC int IMFS_memfile_addblock( |
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262 | IMFS_jnode_t *the_jnode, |
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263 | unsigned int block |
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264 | ) |
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265 | { |
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266 | block_p memory; |
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267 | block_p *block_entry_ptr; |
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268 | |
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269 | IMFS_assert( the_jnode ); |
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270 | IMFS_assert( IMFS_type( the_jnode ) == IMFS_MEMORY_FILE ); |
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271 | |
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272 | /* |
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273 | * Obtain the pointer for the specified block number |
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274 | */ |
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275 | block_entry_ptr = IMFS_memfile_get_block_pointer( the_jnode, block, 1 ); |
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276 | if ( *block_entry_ptr ) |
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277 | return 0; |
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278 | |
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279 | /* |
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280 | * There is no memory for this block number so allocate it. |
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281 | */ |
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282 | memory = memfile_alloc_block(); |
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283 | if ( !memory ) |
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284 | return 1; |
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285 | |
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286 | *block_entry_ptr = memory; |
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287 | return 0; |
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288 | } |
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289 | |
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290 | /* |
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291 | * IMFS_memfile_remove_block |
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292 | * |
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293 | * This routine removes the specified block from the in-memory file. |
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294 | * |
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295 | * NOTE: This is a support routine and is called only to remove |
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296 | * the last block or set of blocks in a file. Removing a |
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297 | * block from the middle of a file would be exceptionally |
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298 | * dangerous and the results unpredictable. |
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299 | */ |
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300 | MEMFILE_STATIC int IMFS_memfile_remove_block( |
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301 | IMFS_jnode_t *the_jnode, |
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302 | unsigned int block |
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303 | ) |
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304 | { |
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305 | block_p *block_ptr; |
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306 | block_p ptr; |
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307 | |
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308 | block_ptr = IMFS_memfile_get_block_pointer( the_jnode, block, 0 ); |
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309 | IMFS_assert( block_ptr ); |
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310 | |
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311 | ptr = *block_ptr; |
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312 | *block_ptr = 0; |
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313 | memfile_free_block( ptr ); |
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314 | |
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315 | return 1; |
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316 | } |
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317 | |
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318 | /* |
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319 | * memfile_free_blocks_in_table |
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320 | * |
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321 | * This is a support routine for IMFS_memfile_remove. It frees all the |
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322 | * blocks in one of the indirection tables. |
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323 | */ |
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324 | static void memfile_free_blocks_in_table( |
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325 | block_p **block_table, |
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326 | int entries |
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327 | ) |
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328 | { |
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329 | int i; |
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330 | block_p *b; |
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331 | |
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332 | /* |
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333 | * Perform internal consistency checks |
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334 | */ |
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335 | IMFS_assert( block_table ); |
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336 | |
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337 | /* |
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338 | * Now go through all the slots in the table and free the memory. |
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339 | */ |
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340 | b = *block_table; |
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341 | |
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342 | for ( i=0 ; i<entries ; i++ ) { |
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343 | if ( b[i] ) { |
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344 | memfile_free_block( b[i] ); |
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345 | b[i] = 0; |
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346 | } |
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347 | } |
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348 | |
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349 | /* |
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350 | * Now that all the blocks in the block table are free, we can |
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351 | * free the block table itself. |
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352 | */ |
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353 | memfile_free_block( *block_table ); |
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354 | *block_table = 0; |
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355 | } |
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356 | |
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357 | /* |
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358 | * IMFS_memfile_remove |
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359 | * |
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360 | * This routine frees all memory associated with an in memory file. |
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361 | * |
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362 | * NOTE: This is an exceptionally conservative implementation. |
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363 | * It will check EVERY pointer which is non-NULL and insure |
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364 | * any child non-NULL pointers are freed. Optimistically, all that |
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365 | * is necessary is to scan until a NULL pointer is found. There |
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366 | * should be no allocated data past that point. |
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367 | * |
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368 | * In experimentation on the powerpc simulator, it was noted |
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369 | * that using blocks which held 128 slots versus 16 slots made |
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370 | * a significant difference in the performance of this routine. |
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371 | * |
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372 | * Regardless until the IMFS implementation is proven, it |
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373 | * is better to stick to simple, easy to understand algorithms. |
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374 | */ |
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375 | IMFS_jnode_t *IMFS_memfile_remove( |
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376 | IMFS_jnode_t *the_jnode |
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377 | ) |
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378 | { |
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379 | IMFS_memfile_t *info; |
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380 | int i; |
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381 | int j; |
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382 | unsigned int to_free; |
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383 | block_p *p; |
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384 | |
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385 | /* |
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386 | * Perform internal consistency checks |
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387 | */ |
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388 | IMFS_assert( the_jnode ); |
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389 | IMFS_assert( IMFS_type( the_jnode ) == IMFS_MEMORY_FILE ); |
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390 | |
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391 | /* |
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392 | * Eventually this could be set smarter at each call to |
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393 | * memfile_free_blocks_in_table to greatly speed this up. |
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394 | */ |
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395 | to_free = IMFS_MEMFILE_BLOCK_SLOTS; |
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396 | |
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397 | /* |
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398 | * Now start freeing blocks in this order: |
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399 | * + indirect |
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400 | * + doubly indirect |
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401 | * + triply indirect |
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402 | */ |
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403 | info = &the_jnode->info.file; |
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404 | |
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405 | if ( info->indirect ) { |
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406 | memfile_free_blocks_in_table( &info->indirect, to_free ); |
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407 | } |
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408 | |
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409 | if ( info->doubly_indirect ) { |
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410 | for ( i=0 ; i<IMFS_MEMFILE_BLOCK_SLOTS ; i++ ) { |
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411 | if ( info->doubly_indirect[i] ) { |
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412 | memfile_free_blocks_in_table( |
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413 | (block_p **)&info->doubly_indirect[i], to_free ); |
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414 | } |
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415 | } |
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416 | memfile_free_blocks_in_table( &info->doubly_indirect, to_free ); |
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417 | |
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418 | } |
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419 | |
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420 | if ( info->triply_indirect ) { |
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421 | for ( i=0 ; i<IMFS_MEMFILE_BLOCK_SLOTS ; i++ ) { |
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422 | p = (block_p *) info->triply_indirect[i]; |
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423 | if ( !p ) /* ensure we have a valid pointer */ |
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424 | break; |
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425 | for ( j=0 ; j<IMFS_MEMFILE_BLOCK_SLOTS ; j++ ) { |
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426 | if ( p[j] ) { |
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427 | memfile_free_blocks_in_table( (block_p **)&p[j], to_free); |
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428 | } |
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429 | } |
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430 | memfile_free_blocks_in_table( |
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431 | (block_p **)&info->triply_indirect[i], to_free ); |
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432 | } |
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433 | memfile_free_blocks_in_table( |
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434 | (block_p **)&info->triply_indirect, to_free ); |
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435 | } |
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436 | |
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437 | return the_jnode; |
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438 | } |
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439 | |
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440 | /* |
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441 | * IMFS_memfile_read |
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442 | * |
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443 | * This routine read from memory file pointed to by the_jnode into |
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444 | * the specified data buffer specified by destination. The file |
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445 | * is NOT extended. An offset greater than the length of the file |
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446 | * is considered an error. Read from an offset for more bytes than |
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447 | * are between the offset and the end of the file will result in |
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448 | * reading the data between offset and the end of the file (truncated |
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449 | * read). |
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450 | */ |
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451 | MEMFILE_STATIC ssize_t IMFS_memfile_read( |
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452 | IMFS_jnode_t *the_jnode, |
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453 | off_t start, |
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454 | unsigned char *destination, |
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455 | unsigned int length |
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456 | ) |
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457 | { |
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458 | block_p *block_ptr; |
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459 | unsigned int block; |
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460 | unsigned int my_length; |
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461 | unsigned int to_copy = 0; |
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462 | unsigned int last_byte; |
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463 | unsigned int copied; |
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464 | unsigned int start_offset; |
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465 | unsigned char *dest; |
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466 | |
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467 | dest = destination; |
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468 | |
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469 | /* |
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470 | * Perform internal consistency checks |
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471 | */ |
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472 | IMFS_assert( the_jnode ); |
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473 | IMFS_assert( IMFS_type( the_jnode ) == IMFS_MEMORY_FILE || |
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474 | IMFS_type( the_jnode ) == IMFS_LINEAR_FILE ); |
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475 | IMFS_assert( dest ); |
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476 | |
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477 | /* |
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478 | * Linear files (as created from a tar file are easier to handle |
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479 | * than block files). |
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480 | */ |
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481 | my_length = length; |
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482 | |
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483 | if ( IMFS_type( the_jnode ) == IMFS_LINEAR_FILE ) { |
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484 | unsigned char *file_ptr; |
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485 | |
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486 | file_ptr = (unsigned char *)the_jnode->info.linearfile.direct; |
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487 | |
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488 | if (my_length > (the_jnode->info.linearfile.size - start)) |
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489 | my_length = the_jnode->info.linearfile.size - start; |
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490 | |
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491 | memcpy(dest, &file_ptr[start], my_length); |
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492 | |
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493 | IMFS_update_atime( the_jnode ); |
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494 | |
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495 | return my_length; |
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496 | } |
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497 | |
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498 | /* |
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499 | * If the last byte we are supposed to read is past the end of this |
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500 | * in memory file, then shorten the length to read. |
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501 | */ |
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502 | last_byte = start + length; |
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503 | if ( last_byte > the_jnode->info.file.size ) |
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504 | my_length = the_jnode->info.file.size - start; |
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505 | |
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506 | copied = 0; |
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507 | |
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508 | /* |
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509 | * Three phases to the read: |
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510 | * + possibly the last part of one block |
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511 | * + all of zero of more blocks |
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512 | * + possibly the first part of one block |
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513 | */ |
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514 | |
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515 | /* |
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516 | * Phase 1: possibly the last part of one block |
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517 | */ |
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518 | start_offset = start % IMFS_MEMFILE_BYTES_PER_BLOCK; |
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519 | block = start / IMFS_MEMFILE_BYTES_PER_BLOCK; |
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520 | if ( start_offset ) { |
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521 | to_copy = IMFS_MEMFILE_BYTES_PER_BLOCK - start_offset; |
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522 | if ( to_copy > my_length ) |
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523 | to_copy = my_length; |
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524 | block_ptr = IMFS_memfile_get_block_pointer( the_jnode, block, 0 ); |
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525 | if ( !block_ptr ) |
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526 | return copied; |
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527 | memcpy( dest, &(*block_ptr)[ start_offset ], to_copy ); |
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528 | dest += to_copy; |
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529 | block++; |
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530 | my_length -= to_copy; |
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531 | copied += to_copy; |
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532 | } |
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533 | |
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534 | /* |
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535 | * Phase 2: all of zero of more blocks |
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536 | */ |
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537 | to_copy = IMFS_MEMFILE_BYTES_PER_BLOCK; |
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538 | while ( my_length >= IMFS_MEMFILE_BYTES_PER_BLOCK ) { |
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539 | block_ptr = IMFS_memfile_get_block_pointer( the_jnode, block, 0 ); |
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540 | if ( !block_ptr ) |
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541 | return copied; |
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542 | memcpy( dest, &(*block_ptr)[ 0 ], to_copy ); |
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543 | dest += to_copy; |
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544 | block++; |
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545 | my_length -= to_copy; |
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546 | copied += to_copy; |
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547 | } |
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548 | |
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549 | /* |
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550 | * Phase 3: possibly the first part of one block |
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551 | */ |
---|
552 | IMFS_assert( my_length < IMFS_MEMFILE_BYTES_PER_BLOCK ); |
---|
553 | |
---|
554 | if ( my_length ) { |
---|
555 | block_ptr = IMFS_memfile_get_block_pointer( the_jnode, block, 0 ); |
---|
556 | if ( !block_ptr ) |
---|
557 | return copied; |
---|
558 | memcpy( dest, &(*block_ptr)[ 0 ], my_length ); |
---|
559 | copied += my_length; |
---|
560 | } |
---|
561 | |
---|
562 | IMFS_update_atime( the_jnode ); |
---|
563 | |
---|
564 | return copied; |
---|
565 | } |
---|
566 | |
---|
567 | /* |
---|
568 | * IMFS_memfile_write |
---|
569 | * |
---|
570 | * This routine writes the specified data buffer into the in memory |
---|
571 | * file pointed to by the_jnode. The file is extended as needed. |
---|
572 | */ |
---|
573 | MEMFILE_STATIC ssize_t IMFS_memfile_write( |
---|
574 | IMFS_jnode_t *the_jnode, |
---|
575 | off_t start, |
---|
576 | const unsigned char *source, |
---|
577 | unsigned int length |
---|
578 | ) |
---|
579 | { |
---|
580 | block_p *block_ptr; |
---|
581 | unsigned int block; |
---|
582 | int status; |
---|
583 | unsigned int my_length; |
---|
584 | unsigned int to_copy = 0; |
---|
585 | unsigned int last_byte; |
---|
586 | unsigned int start_offset; |
---|
587 | int copied; |
---|
588 | const unsigned char *src; |
---|
589 | |
---|
590 | src = source; |
---|
591 | |
---|
592 | /* |
---|
593 | * Perform internal consistency checks |
---|
594 | */ |
---|
595 | IMFS_assert( source ); |
---|
596 | IMFS_assert( the_jnode ); |
---|
597 | IMFS_assert( IMFS_type( the_jnode ) == IMFS_MEMORY_FILE ); |
---|
598 | |
---|
599 | my_length = length; |
---|
600 | /* |
---|
601 | * If the last byte we are supposed to write is past the end of this |
---|
602 | * in memory file, then extend the length. |
---|
603 | */ |
---|
604 | |
---|
605 | last_byte = start + my_length; |
---|
606 | if ( last_byte > the_jnode->info.file.size ) { |
---|
607 | bool zero_fill = start > the_jnode->info.file.size; |
---|
608 | |
---|
609 | status = IMFS_memfile_extend( the_jnode, zero_fill, last_byte ); |
---|
610 | if ( status ) |
---|
611 | return status; |
---|
612 | } |
---|
613 | |
---|
614 | copied = 0; |
---|
615 | |
---|
616 | /* |
---|
617 | * Three phases to the write: |
---|
618 | * + possibly the last part of one block |
---|
619 | * + all of zero of more blocks |
---|
620 | * + possibly the first part of one block |
---|
621 | */ |
---|
622 | |
---|
623 | /* |
---|
624 | * Phase 1: possibly the last part of one block |
---|
625 | */ |
---|
626 | start_offset = start % IMFS_MEMFILE_BYTES_PER_BLOCK; |
---|
627 | block = start / IMFS_MEMFILE_BYTES_PER_BLOCK; |
---|
628 | if ( start_offset ) { |
---|
629 | to_copy = IMFS_MEMFILE_BYTES_PER_BLOCK - start_offset; |
---|
630 | if ( to_copy > my_length ) |
---|
631 | to_copy = my_length; |
---|
632 | block_ptr = IMFS_memfile_get_block_pointer( the_jnode, block, 0 ); |
---|
633 | if ( !block_ptr ) |
---|
634 | return copied; |
---|
635 | #if 0 |
---|
636 | fprintf( |
---|
637 | stderr, |
---|
638 | "write %d at %d in %d: %*s\n", |
---|
639 | to_copy, |
---|
640 | start_offset, |
---|
641 | block, |
---|
642 | to_copy, |
---|
643 | src |
---|
644 | ); |
---|
645 | #endif |
---|
646 | memcpy( &(*block_ptr)[ start_offset ], src, to_copy ); |
---|
647 | src += to_copy; |
---|
648 | block++; |
---|
649 | my_length -= to_copy; |
---|
650 | copied += to_copy; |
---|
651 | } |
---|
652 | |
---|
653 | /* |
---|
654 | * Phase 2: all of zero of more blocks |
---|
655 | */ |
---|
656 | |
---|
657 | to_copy = IMFS_MEMFILE_BYTES_PER_BLOCK; |
---|
658 | while ( my_length >= IMFS_MEMFILE_BYTES_PER_BLOCK ) { |
---|
659 | block_ptr = IMFS_memfile_get_block_pointer( the_jnode, block, 0 ); |
---|
660 | if ( !block_ptr ) |
---|
661 | return copied; |
---|
662 | #if 0 |
---|
663 | fprintf(stdout, "write %d in %d: %*s\n", to_copy, block, to_copy, src ); |
---|
664 | #endif |
---|
665 | memcpy( &(*block_ptr)[ 0 ], src, to_copy ); |
---|
666 | src += to_copy; |
---|
667 | block++; |
---|
668 | my_length -= to_copy; |
---|
669 | copied += to_copy; |
---|
670 | } |
---|
671 | |
---|
672 | /* |
---|
673 | * Phase 3: possibly the first part of one block |
---|
674 | */ |
---|
675 | IMFS_assert( my_length < IMFS_MEMFILE_BYTES_PER_BLOCK ); |
---|
676 | |
---|
677 | to_copy = my_length; |
---|
678 | if ( my_length ) { |
---|
679 | block_ptr = IMFS_memfile_get_block_pointer( the_jnode, block, 0 ); |
---|
680 | if ( !block_ptr ) |
---|
681 | return copied; |
---|
682 | #if 0 |
---|
683 | fprintf(stdout, "write %d in %d: %*s\n", to_copy, block, to_copy, src ); |
---|
684 | #endif |
---|
685 | memcpy( &(*block_ptr)[ 0 ], src, my_length ); |
---|
686 | my_length = 0; |
---|
687 | copied += to_copy; |
---|
688 | } |
---|
689 | |
---|
690 | IMFS_mtime_ctime_update( the_jnode ); |
---|
691 | |
---|
692 | return copied; |
---|
693 | } |
---|
694 | |
---|
695 | /* |
---|
696 | * IMFS_memfile_get_block_pointer |
---|
697 | * |
---|
698 | * This routine looks up the block pointer associated with the given block |
---|
699 | * number. If that block has not been allocated and "malloc_it" is |
---|
700 | * TRUE, then the block is allocated. Otherwise, it is an error. |
---|
701 | */ |
---|
702 | #if 0 |
---|
703 | block_p *IMFS_memfile_get_block_pointer_DEBUG( |
---|
704 | IMFS_jnode_t *the_jnode, |
---|
705 | unsigned int block, |
---|
706 | int malloc_it |
---|
707 | ); |
---|
708 | |
---|
709 | block_p *IMFS_memfile_get_block_pointer( |
---|
710 | IMFS_jnode_t *the_jnode, |
---|
711 | unsigned int block, |
---|
712 | int malloc_it |
---|
713 | ) |
---|
714 | { |
---|
715 | block_p *p; |
---|
716 | |
---|
717 | p = IMFS_memfile_get_block_pointer_DEBUG( the_jnode, block, malloc_it ); |
---|
718 | fprintf(stdout, "(%d -> %p) ", block, p ); |
---|
719 | return p; |
---|
720 | } |
---|
721 | |
---|
722 | block_p *IMFS_memfile_get_block_pointer_DEBUG( |
---|
723 | #else |
---|
724 | block_p *IMFS_memfile_get_block_pointer( |
---|
725 | #endif |
---|
726 | IMFS_jnode_t *the_jnode, |
---|
727 | unsigned int block, |
---|
728 | int malloc_it |
---|
729 | ) |
---|
730 | { |
---|
731 | unsigned int my_block; |
---|
732 | IMFS_memfile_t *info; |
---|
733 | unsigned int singly; |
---|
734 | unsigned int doubly; |
---|
735 | unsigned int triply; |
---|
736 | block_p *p; |
---|
737 | block_p *p1; |
---|
738 | block_p *p2; |
---|
739 | |
---|
740 | /* |
---|
741 | * Perform internal consistency checks |
---|
742 | */ |
---|
743 | IMFS_assert( the_jnode ); |
---|
744 | IMFS_assert( IMFS_type( the_jnode ) == IMFS_MEMORY_FILE ); |
---|
745 | |
---|
746 | info = &the_jnode->info.file; |
---|
747 | my_block = block; |
---|
748 | |
---|
749 | /* |
---|
750 | * Is the block number in the simple indirect portion? |
---|
751 | */ |
---|
752 | if ( my_block <= LAST_INDIRECT ) { |
---|
753 | p = info->indirect; |
---|
754 | |
---|
755 | if ( malloc_it ) { |
---|
756 | |
---|
757 | if ( !p ) { |
---|
758 | p = memfile_alloc_block(); |
---|
759 | if ( !p ) |
---|
760 | return 0; |
---|
761 | info->indirect = p; |
---|
762 | } |
---|
763 | return &info->indirect[ my_block ]; |
---|
764 | } |
---|
765 | |
---|
766 | if ( !p ) |
---|
767 | return 0; |
---|
768 | |
---|
769 | return &info->indirect[ my_block ]; |
---|
770 | } |
---|
771 | |
---|
772 | /* |
---|
773 | * Is the block number in the doubly indirect portion? |
---|
774 | */ |
---|
775 | |
---|
776 | if ( my_block <= LAST_DOUBLY_INDIRECT ) { |
---|
777 | my_block -= FIRST_DOUBLY_INDIRECT; |
---|
778 | |
---|
779 | singly = my_block % IMFS_MEMFILE_BLOCK_SLOTS; |
---|
780 | doubly = my_block / IMFS_MEMFILE_BLOCK_SLOTS; |
---|
781 | |
---|
782 | p = info->doubly_indirect; |
---|
783 | if ( malloc_it ) { |
---|
784 | |
---|
785 | if ( !p ) { |
---|
786 | p = memfile_alloc_block(); |
---|
787 | if ( !p ) |
---|
788 | return 0; |
---|
789 | info->doubly_indirect = p; |
---|
790 | } |
---|
791 | |
---|
792 | p1 = (block_p *)p[ doubly ]; |
---|
793 | if ( !p1 ) { |
---|
794 | p1 = memfile_alloc_block(); |
---|
795 | if ( !p1 ) |
---|
796 | return 0; |
---|
797 | p[ doubly ] = (block_p) p1; |
---|
798 | } |
---|
799 | |
---|
800 | return (block_p *)&p1[ singly ]; |
---|
801 | } |
---|
802 | |
---|
803 | if ( !p ) |
---|
804 | return 0; |
---|
805 | |
---|
806 | p = (block_p *)p[ doubly ]; |
---|
807 | if ( !p ) |
---|
808 | return 0; |
---|
809 | |
---|
810 | return (block_p *)&p[ singly ]; |
---|
811 | } |
---|
812 | |
---|
813 | /* |
---|
814 | * Is the block number in the triply indirect portion? |
---|
815 | */ |
---|
816 | if ( my_block <= LAST_TRIPLY_INDIRECT ) { |
---|
817 | my_block -= FIRST_TRIPLY_INDIRECT; |
---|
818 | |
---|
819 | singly = my_block % IMFS_MEMFILE_BLOCK_SLOTS; |
---|
820 | doubly = my_block / IMFS_MEMFILE_BLOCK_SLOTS; |
---|
821 | triply = doubly / IMFS_MEMFILE_BLOCK_SLOTS; |
---|
822 | doubly %= IMFS_MEMFILE_BLOCK_SLOTS; |
---|
823 | |
---|
824 | p = info->triply_indirect; |
---|
825 | |
---|
826 | if ( malloc_it ) { |
---|
827 | if ( !p ) { |
---|
828 | p = memfile_alloc_block(); |
---|
829 | if ( !p ) |
---|
830 | return 0; |
---|
831 | info->triply_indirect = p; |
---|
832 | } |
---|
833 | |
---|
834 | p1 = (block_p *) p[ triply ]; |
---|
835 | if ( !p1 ) { |
---|
836 | p1 = memfile_alloc_block(); |
---|
837 | if ( !p1 ) |
---|
838 | return 0; |
---|
839 | p[ triply ] = (block_p) p1; |
---|
840 | } |
---|
841 | |
---|
842 | p2 = (block_p *)p1[ doubly ]; |
---|
843 | if ( !p2 ) { |
---|
844 | p2 = memfile_alloc_block(); |
---|
845 | if ( !p2 ) |
---|
846 | return 0; |
---|
847 | p1[ doubly ] = (block_p) p2; |
---|
848 | } |
---|
849 | return (block_p *)&p2[ singly ]; |
---|
850 | } |
---|
851 | |
---|
852 | if ( !p ) |
---|
853 | return 0; |
---|
854 | |
---|
855 | p1 = (block_p *) p[ triply ]; |
---|
856 | if ( !p1 ) |
---|
857 | return 0; |
---|
858 | |
---|
859 | p2 = (block_p *)p1[ doubly ]; |
---|
860 | if ( !p2 ) |
---|
861 | return 0; |
---|
862 | |
---|
863 | return (block_p *)&p2[ singly ]; |
---|
864 | } |
---|
865 | |
---|
866 | /* |
---|
867 | * This means the requested block number is out of range. |
---|
868 | */ |
---|
869 | return 0; |
---|
870 | } |
---|
871 | |
---|
872 | /* |
---|
873 | * memfile_alloc_block |
---|
874 | * |
---|
875 | * Allocate a block for an in-memory file. |
---|
876 | */ |
---|
877 | int memfile_blocks_allocated = 0; |
---|
878 | |
---|
879 | void *memfile_alloc_block(void) |
---|
880 | { |
---|
881 | void *memory; |
---|
882 | |
---|
883 | memory = (void *)calloc(1, IMFS_MEMFILE_BYTES_PER_BLOCK); |
---|
884 | if ( memory ) |
---|
885 | memfile_blocks_allocated++; |
---|
886 | |
---|
887 | return memory; |
---|
888 | } |
---|
889 | |
---|
890 | /* |
---|
891 | * memfile_free_block |
---|
892 | * |
---|
893 | * Free a block from an in-memory file. |
---|
894 | */ |
---|
895 | void memfile_free_block( |
---|
896 | void *memory |
---|
897 | ) |
---|
898 | { |
---|
899 | free(memory); |
---|
900 | memfile_blocks_allocated--; |
---|
901 | } |
---|