1 | /* |
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2 | * open() - POSIX 1003.1 5.3.1 - Open a File |
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3 | * |
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4 | * COPYRIGHT (c) 1989-1999. |
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5 | * On-Line Applications Research Corporation (OAR). |
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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 | |
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14 | #if HAVE_CONFIG_H |
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15 | #include "config.h" |
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16 | #endif |
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17 | |
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18 | #include <rtems/libio_.h> |
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19 | |
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20 | #include <unistd.h> |
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21 | |
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22 | /* |
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23 | * Returns file descriptor on success or -1 and errno set to one of the |
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24 | * following: |
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25 | * |
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26 | * EACCESS - Seach permission is denied on a component of the path prefix, |
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27 | * or the file exists and the permissions specified by the |
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28 | * flags are denied, or the file does not exist and write |
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29 | * permission is denied for the parent directory of the file |
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30 | * to be created, or O_TRUNC is specified and write permission |
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31 | * is denied. |
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32 | * EEXIST - O_CREAT and O_EXCL are set and the named file exists. |
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33 | * EINTR - The open( operation was interrupted by a signal. |
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34 | * EINVAL - This implementation does not support synchronized IO for this |
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35 | * file. |
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36 | * EISDIR - The named file is a directory and the flags argument |
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37 | * specified write or read/write access. |
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38 | * EMFILE - Too many file descriptors are in used by this process. |
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39 | * ENAMETOOLONG - |
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40 | * The length of the path exceeds PATH_MAX or a pathname |
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41 | * component is longer than NAME_MAX while POSIX_NO_TRUNC |
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42 | * is in effect. |
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43 | * ENFILE - Too many files are open in the system. |
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44 | * ENOENT - O_CREAT is not set and and the anmed file does not exist, |
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45 | * or O_CREAT is set and eitehr the path prefix does not exist |
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46 | * or the path argument points to an empty string. |
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47 | * ENOSPC - The directory or file system that would contain the new file |
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48 | * cannot be extended. |
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49 | * ENOTDIR - A component of the path prefix is not a directory. |
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50 | * ENXIO - O_NONBLOCK is set, the named file is a FIFO, O_WRONLY is |
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51 | * set, and no process has the file open for reading. |
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52 | * EROFS - The named file resides on a read-only file system and either |
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53 | * O_WRONLY, O_RDWR, O_CREAT (if the file does not exist), or |
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54 | * O_TRUNC is set in the flags argument. |
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55 | */ |
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56 | |
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57 | int open( |
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58 | const char *pathname, |
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59 | int flags, |
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60 | ... |
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61 | ) |
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62 | { |
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63 | va_list ap; |
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64 | int mode; |
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65 | int rc; |
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66 | rtems_libio_t *iop = 0; |
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67 | int status; |
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68 | rtems_filesystem_location_info_t loc; |
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69 | int eval_flags; |
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70 | |
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71 | |
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72 | /* |
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73 | * Set the Evaluation flags |
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74 | */ |
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75 | |
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76 | eval_flags = 0; |
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77 | status = flags + 1; |
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78 | if ( ( status & _FREAD ) == _FREAD ) |
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79 | eval_flags |= RTEMS_LIBIO_PERMS_READ; |
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80 | if ( ( status & _FWRITE ) == _FWRITE ) |
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81 | eval_flags |= RTEMS_LIBIO_PERMS_WRITE; |
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82 | |
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83 | |
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84 | va_start(ap, flags); |
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85 | |
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86 | mode = va_arg( ap, int ); |
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87 | |
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88 | /* |
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89 | * NOTE: This comment is OBSOLETE. The proper way to do this now |
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90 | * would be to support a magic mounted file system. |
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91 | * |
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92 | * Additional external I/O handlers would be supported by adding |
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93 | * code to pick apart the pathname appropriately. The networking |
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94 | * code does not require changes here since network file |
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95 | * descriptors are obtained using socket(), not open(). |
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96 | */ |
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97 | |
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98 | /* allocate a file control block */ |
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99 | iop = rtems_libio_allocate(); |
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100 | if ( iop == 0 ) { |
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101 | rc = ENFILE; |
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102 | goto done; |
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103 | } |
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104 | |
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105 | /* |
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106 | * See if the file exists. |
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107 | */ |
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108 | |
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109 | status = rtems_filesystem_evaluate_path( |
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110 | pathname, eval_flags, &loc, TRUE ); |
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111 | |
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112 | if ( status == -1 ) { |
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113 | if ( errno != ENOENT ) { |
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114 | rc = errno; |
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115 | goto done; |
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116 | } |
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117 | |
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118 | /* If the file does not exist and we are not trying to create it--> error */ |
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119 | if ( !(flags & O_CREAT) ) { |
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120 | rc = ENOENT; |
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121 | goto done; |
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122 | } |
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123 | |
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124 | /* Create the node for the new regular file */ |
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125 | rc = mknod( pathname, S_IFREG | mode, 0LL ); |
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126 | if ( rc ) { |
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127 | rc = errno; |
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128 | goto done; |
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129 | } |
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130 | |
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131 | /* Sanity check to see if the file name exists after the mknod() */ |
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132 | status = rtems_filesystem_evaluate_path( pathname, 0x0, &loc, TRUE ); |
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133 | if ( status != 0 ) { /* The file did not exist */ |
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134 | rc = EACCES; |
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135 | goto done; |
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136 | } |
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137 | |
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138 | } else if ((flags & (O_EXCL|O_CREAT)) == (O_EXCL|O_CREAT)) { |
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139 | /* We were trying to create a file that already exists */ |
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140 | rc = EEXIST; |
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141 | goto done; |
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142 | } |
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143 | |
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144 | /* |
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145 | * Fill in the file control block based on the loc structure |
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146 | * returned by successful path evaluation. |
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147 | */ |
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148 | |
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149 | iop->offset = 0; |
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150 | iop->handlers = loc.handlers; |
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151 | iop->file_info = loc.node_access; |
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152 | iop->flags |= rtems_libio_fcntl_flags( flags ); |
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153 | iop->pathinfo = loc; |
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154 | |
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155 | if ( !iop->handlers->open_h ) { |
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156 | rc = ENOTSUP; |
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157 | goto done; |
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158 | } |
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159 | |
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160 | rc = (*iop->handlers->open_h)( iop, pathname, flags, mode ); |
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161 | if ( rc ) |
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162 | goto done; |
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163 | |
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164 | /* |
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165 | * Optionally truncate the file. |
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166 | */ |
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167 | |
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168 | if ( (flags & O_TRUNC) == O_TRUNC ) { |
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169 | rc = ftruncate( iop - rtems_libio_iops, 0 ); |
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170 | } |
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171 | |
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172 | /* |
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173 | * Single exit and clean up path. |
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174 | */ |
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175 | |
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176 | done: |
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177 | va_end(ap); |
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178 | |
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179 | if ( rc ) { |
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180 | if ( iop ) |
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181 | rtems_libio_free( iop ); |
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182 | set_errno_and_return_minus_one( rc ); |
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183 | } |
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184 | |
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185 | rtems_filesystem_freenode( &loc ); |
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186 | |
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187 | return iop - rtems_libio_iops; |
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188 | } |
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189 | |
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190 | /* |
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191 | * _open_r |
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192 | * |
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193 | * This is the Newlib dependent reentrant version of open(). |
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194 | */ |
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195 | |
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196 | #if defined(RTEMS_NEWLIB) |
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197 | |
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198 | #include <reent.h> |
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199 | |
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200 | int _open_r( |
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201 | struct _reent *ptr, |
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202 | const char *buf, |
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203 | int flags, |
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204 | int mode |
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205 | ) |
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206 | { |
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207 | return open( buf, flags, mode ); |
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208 | } |
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209 | #endif |
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