1 | /** |
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2 | * @file |
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3 | * |
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4 | * @brief RTEMS File Sysyem Path Eval Support |
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5 | * @ingroup LibIOInternal |
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6 | */ |
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7 | |
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8 | /* |
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9 | * Copyright (c) 2012 embedded brains GmbH. All rights reserved. |
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10 | * |
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11 | * embedded brains GmbH |
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12 | * Obere Lagerstr. 30 |
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13 | * 82178 Puchheim |
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14 | * Germany |
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15 | * <rtems@embedded-brains.de> |
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16 | * |
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17 | * The license and distribution terms for this file may be |
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18 | * found in the file LICENSE in this distribution or at |
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19 | * http://www.rtems.org/license/LICENSE. |
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20 | */ |
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21 | |
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22 | #if HAVE_CONFIG_H |
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23 | #include "config.h" |
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24 | #endif |
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25 | |
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26 | #include <rtems/libio_.h> |
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27 | |
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28 | #include <string.h> |
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29 | |
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30 | static size_t get_parentpathlen(const char *path, size_t pathlen) |
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31 | { |
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32 | while (pathlen > 0) { |
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33 | size_t i = pathlen - 1; |
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34 | |
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35 | if (rtems_filesystem_is_delimiter(path [i])) { |
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36 | return pathlen; |
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37 | } |
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38 | |
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39 | pathlen = i; |
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40 | } |
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41 | |
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42 | return 0; |
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43 | } |
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44 | |
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45 | static void set_startloc( |
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46 | rtems_filesystem_eval_path_context_t *ctx, |
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47 | rtems_filesystem_global_location_t *const *global_root_ptr, |
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48 | rtems_filesystem_global_location_t *const *global_current_ptr |
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49 | ) |
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50 | { |
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51 | if (ctx->pathlen > 0) { |
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52 | char c = ctx->path [0]; |
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53 | |
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54 | ctx->rootloc = rtems_filesystem_global_location_obtain(global_root_ptr); |
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55 | |
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56 | if (rtems_filesystem_is_delimiter(c)) { |
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57 | ++ctx->path; |
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58 | --ctx->pathlen; |
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59 | ctx->startloc = rtems_filesystem_global_location_obtain( |
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60 | &ctx->rootloc |
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61 | ); |
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62 | } else { |
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63 | ctx->startloc = rtems_filesystem_global_location_obtain( |
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64 | global_current_ptr |
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65 | ); |
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66 | } |
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67 | } else { |
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68 | ctx->rootloc = rtems_filesystem_global_location_obtain_null(); |
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69 | ctx->startloc = rtems_filesystem_global_location_obtain_null(); |
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70 | errno = ENOENT; |
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71 | } |
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72 | } |
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73 | |
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74 | static void check_access( |
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75 | rtems_filesystem_eval_path_context_t *ctx, |
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76 | int eval_flags |
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77 | ) |
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78 | { |
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79 | const rtems_filesystem_location_info_t *currentloc = &ctx->currentloc; |
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80 | const rtems_filesystem_mount_table_entry_t *mt_entry = currentloc->mt_entry; |
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81 | |
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82 | if ((eval_flags & RTEMS_FS_PERMS_WRITE) == 0 || mt_entry->writeable) { |
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83 | struct stat st; |
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84 | int rv; |
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85 | |
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86 | st.st_mode = 0; |
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87 | st.st_uid = 0; |
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88 | st.st_gid = 0; |
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89 | rv = (*currentloc->handlers->fstat_h)(currentloc, &st); |
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90 | if (rv == 0) { |
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91 | bool access_ok = rtems_filesystem_check_access( |
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92 | eval_flags, |
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93 | st.st_mode, |
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94 | st.st_uid, |
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95 | st.st_gid |
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96 | ); |
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97 | |
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98 | if (!access_ok) { |
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99 | rtems_filesystem_eval_path_error(ctx, EACCES); |
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100 | } |
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101 | } else { |
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102 | rtems_filesystem_eval_path_error(ctx, 0); |
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103 | } |
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104 | } else { |
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105 | rtems_filesystem_eval_path_error(ctx, EROFS); |
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106 | } |
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107 | } |
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108 | |
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109 | void rtems_filesystem_eval_path_continue( |
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110 | rtems_filesystem_eval_path_context_t *ctx |
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111 | ) |
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112 | { |
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113 | int eval_flags; |
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114 | |
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115 | while (ctx->pathlen > 0) { |
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116 | (*ctx->currentloc.mt_entry->ops->eval_path_h)(ctx); |
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117 | } |
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118 | |
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119 | eval_flags = rtems_filesystem_eval_path_get_flags(ctx); |
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120 | if (rtems_filesystem_eval_path_has_token(ctx)) { |
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121 | bool make = (eval_flags & RTEMS_FS_MAKE) != 0; |
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122 | |
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123 | if (make) { |
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124 | check_access(ctx, RTEMS_FS_PERMS_WRITE); |
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125 | } else { |
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126 | rtems_filesystem_eval_path_error(ctx, ENOENT); |
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127 | } |
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128 | } else { |
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129 | bool exclusive = (eval_flags & RTEMS_FS_EXCLUSIVE) != 0; |
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130 | |
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131 | if (!exclusive) { |
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132 | check_access(ctx, ctx->flags); |
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133 | } else { |
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134 | rtems_filesystem_eval_path_error(ctx, EEXIST); |
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135 | } |
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136 | } |
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137 | } |
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138 | |
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139 | rtems_filesystem_location_info_t * |
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140 | rtems_filesystem_eval_path_start_with_root_and_current( |
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141 | rtems_filesystem_eval_path_context_t *ctx, |
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142 | const char *path, |
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143 | size_t pathlen, |
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144 | int eval_flags, |
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145 | rtems_filesystem_global_location_t *const *global_root_ptr, |
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146 | rtems_filesystem_global_location_t *const *global_current_ptr |
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147 | ) |
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148 | { |
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149 | memset(ctx, 0, sizeof(*ctx)); |
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150 | |
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151 | ctx->path = path; |
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152 | ctx->pathlen = pathlen; |
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153 | ctx->flags = eval_flags; |
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154 | |
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155 | set_startloc(ctx, global_root_ptr, global_current_ptr); |
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156 | |
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157 | rtems_filesystem_instance_lock(&ctx->startloc->location); |
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158 | |
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159 | rtems_filesystem_location_clone( |
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160 | &ctx->currentloc, |
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161 | &ctx->startloc->location |
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162 | ); |
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163 | |
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164 | rtems_filesystem_eval_path_continue(ctx); |
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165 | |
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166 | return &ctx->currentloc; |
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167 | } |
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168 | |
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169 | rtems_filesystem_location_info_t * |
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170 | rtems_filesystem_eval_path_start( |
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171 | rtems_filesystem_eval_path_context_t *ctx, |
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172 | const char *path, |
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173 | int eval_flags |
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174 | ) |
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175 | { |
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176 | return rtems_filesystem_eval_path_start_with_root_and_current( |
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177 | ctx, |
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178 | path, |
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179 | strlen(path), |
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180 | eval_flags, |
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181 | &rtems_filesystem_root, |
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182 | &rtems_filesystem_current |
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183 | ); |
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184 | } |
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185 | |
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186 | rtems_filesystem_location_info_t * |
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187 | rtems_filesystem_eval_path_start_with_parent( |
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188 | rtems_filesystem_eval_path_context_t *ctx, |
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189 | const char *path, |
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190 | int eval_flags, |
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191 | rtems_filesystem_location_info_t *parentloc, |
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192 | int parent_eval_flags |
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193 | ) |
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194 | { |
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195 | size_t pathlen = strlen(path); |
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196 | const char *parentpath = path; |
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197 | size_t parentpathlen = get_parentpathlen(path, pathlen); |
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198 | const char *name = NULL; |
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199 | size_t namelen = 0; |
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200 | const rtems_filesystem_location_info_t *currentloc = NULL; |
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201 | |
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202 | if (pathlen > 0) { |
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203 | if (parentpathlen == 0) { |
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204 | parentpath = "."; |
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205 | parentpathlen = 1; |
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206 | name = path; |
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207 | namelen = pathlen; |
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208 | } else { |
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209 | name = path + parentpathlen; |
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210 | namelen = pathlen - parentpathlen; |
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211 | } |
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212 | } |
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213 | |
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214 | currentloc = rtems_filesystem_eval_path_start_with_root_and_current( |
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215 | ctx, |
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216 | parentpath, |
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217 | parentpathlen, |
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218 | parent_eval_flags, |
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219 | &rtems_filesystem_root, |
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220 | &rtems_filesystem_current |
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221 | ); |
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222 | |
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223 | rtems_filesystem_location_clone(parentloc, currentloc); |
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224 | |
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225 | ctx->path = name; |
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226 | ctx->pathlen = namelen; |
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227 | ctx->flags = eval_flags; |
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228 | |
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229 | rtems_filesystem_eval_path_continue(ctx); |
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230 | |
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231 | return &ctx->currentloc; |
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232 | } |
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233 | |
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234 | void rtems_filesystem_eval_path_recursive( |
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235 | rtems_filesystem_eval_path_context_t *ctx, |
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236 | const char *path, |
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237 | size_t pathlen |
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238 | ) |
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239 | { |
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240 | if (pathlen > 0) { |
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241 | if (ctx->recursionlevel < RTEMS_FILESYSTEM_SYMLOOP_MAX) { |
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242 | const char *saved_path = ctx->path; |
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243 | size_t saved_pathlen = ctx->pathlen; |
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244 | |
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245 | if (rtems_filesystem_is_delimiter(path [0])) { |
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246 | rtems_filesystem_eval_path_restart(ctx, &ctx->rootloc); |
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247 | } |
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248 | |
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249 | ctx->path = path; |
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250 | ctx->pathlen = pathlen; |
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251 | |
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252 | ++ctx->recursionlevel; |
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253 | while (ctx->pathlen > 0) { |
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254 | (*ctx->currentloc.mt_entry->ops->eval_path_h)(ctx); |
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255 | } |
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256 | --ctx->recursionlevel; |
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257 | |
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258 | ctx->path = saved_path; |
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259 | ctx->pathlen = saved_pathlen; |
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260 | } else { |
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261 | rtems_filesystem_eval_path_error(ctx, ELOOP); |
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262 | } |
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263 | } else { |
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264 | rtems_filesystem_eval_path_error(ctx, ENOENT); |
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265 | } |
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266 | } |
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267 | |
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268 | void rtems_filesystem_eval_path_error( |
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269 | rtems_filesystem_eval_path_context_t *ctx, |
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270 | int eno |
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271 | ) |
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272 | { |
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273 | ctx->path = NULL; |
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274 | ctx->pathlen = 0; |
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275 | ctx->token = NULL; |
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276 | ctx->tokenlen = 0; |
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277 | |
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278 | if (!rtems_filesystem_location_is_null(&ctx->currentloc)) { |
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279 | if (eno != 0) { |
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280 | errno = eno; |
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281 | } |
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282 | |
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283 | rtems_filesystem_location_detach(&ctx->currentloc); |
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284 | } |
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285 | } |
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286 | |
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287 | static void free_location(rtems_filesystem_location_info_t *loc) |
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288 | { |
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289 | rtems_filesystem_mt_entry_declare_lock_context(lock_context); |
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290 | |
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291 | (*loc->mt_entry->ops->freenod_h)(loc); |
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292 | |
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293 | rtems_filesystem_mt_entry_lock(lock_context); |
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294 | rtems_chain_extract_unprotected(&loc->mt_entry_node); |
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295 | rtems_filesystem_mt_entry_unlock(lock_context); |
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296 | } |
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297 | |
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298 | void rtems_filesystem_eval_path_cleanup( |
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299 | rtems_filesystem_eval_path_context_t *ctx |
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300 | ) |
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301 | { |
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302 | free_location(&ctx->currentloc); |
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303 | rtems_filesystem_instance_unlock(&ctx->startloc->location); |
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304 | rtems_filesystem_global_location_release(ctx->startloc, false); |
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305 | rtems_filesystem_global_location_release(ctx->rootloc, false); |
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306 | } |
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307 | |
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308 | void rtems_filesystem_eval_path_cleanup_with_parent( |
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309 | rtems_filesystem_eval_path_context_t *ctx, |
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310 | rtems_filesystem_location_info_t *parentloc |
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311 | ) |
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312 | { |
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313 | free_location(parentloc); |
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314 | rtems_filesystem_eval_path_cleanup(ctx); |
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315 | } |
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316 | |
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317 | void rtems_filesystem_eval_path_restart( |
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318 | rtems_filesystem_eval_path_context_t *ctx, |
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319 | rtems_filesystem_global_location_t **newstartloc_ptr |
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320 | ) |
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321 | { |
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322 | free_location(&ctx->currentloc); |
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323 | rtems_filesystem_instance_unlock(&ctx->startloc->location); |
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324 | rtems_filesystem_global_location_assign( |
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325 | &ctx->startloc, |
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326 | rtems_filesystem_global_location_obtain(newstartloc_ptr) |
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327 | ); |
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328 | rtems_filesystem_instance_lock(&ctx->startloc->location); |
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329 | rtems_filesystem_location_clone(&ctx->currentloc, &ctx->startloc->location); |
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330 | } |
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