1 | /* SPDX-License-Identifier: BSD-2-Clause */ |
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2 | |
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3 | /** |
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4 | * @file |
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5 | */ |
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6 | |
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7 | /* |
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8 | * Copyright (c) 2016 Gedare Bloom. |
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9 | * |
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10 | * Redistribution and use in source and binary forms, with or without |
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11 | * modification, are permitted provided that the following conditions |
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12 | * are met: |
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13 | * 1. Redistributions of source code must retain the above copyright |
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14 | * notice, this list of conditions and the following disclaimer. |
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15 | * 2. Redistributions in binary form must reproduce the above copyright |
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16 | * notice, this list of conditions and the following disclaimer in the |
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17 | * documentation and/or other materials provided with the distribution. |
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18 | * |
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19 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
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20 | * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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21 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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22 | * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE |
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23 | * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
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24 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
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25 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
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26 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
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27 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
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28 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
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29 | * POSSIBILITY OF SUCH DAMAGE. |
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30 | */ |
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31 | |
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32 | #ifdef HAVE_CONFIG_H |
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33 | #include "config.h" |
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34 | #endif |
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35 | |
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36 | #include <sys/mman.h> |
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37 | #include <errno.h> |
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38 | #include <unistd.h> |
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39 | #include <fcntl.h> |
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40 | #include <sys/stat.h> |
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41 | |
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42 | #include <rtems/libio_.h> |
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43 | #include <rtems/seterr.h> |
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44 | |
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45 | #include <rtems/posix/shmimpl.h> |
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46 | #include <rtems/score/wkspace.h> |
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47 | #include <rtems/sysinit.h> |
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48 | |
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49 | static const rtems_filesystem_file_handlers_r shm_handlers; |
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50 | |
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51 | static int shm_fstat( |
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52 | const rtems_filesystem_location_info_t *loc, |
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53 | struct stat *buf |
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54 | ) |
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55 | { |
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56 | POSIX_Shm_Control *shm = loc_to_shm( loc ); |
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57 | |
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58 | if ( shm == NULL ) |
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59 | rtems_set_errno_and_return_minus_one( EIO ); |
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60 | |
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61 | /* mandatory for shm objects */ |
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62 | buf->st_uid = shm->uid; |
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63 | buf->st_gid = shm->gid; |
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64 | buf->st_size = shm->shm_object.size; |
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65 | buf->st_mode = shm->mode; |
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66 | |
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67 | /* optional for shm objects */ |
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68 | buf->st_atime = shm->atime; |
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69 | buf->st_mtime = shm->mtime; |
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70 | buf->st_ctime = shm->ctime; |
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71 | |
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72 | return 0; |
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73 | } |
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74 | |
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75 | /* read() is unspecified for shared memory objects */ |
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76 | static ssize_t shm_read( rtems_libio_t *iop, void *buffer, size_t count ) |
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77 | { |
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78 | ssize_t bytes_read; |
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79 | POSIX_Shm_Control *shm = iop_to_shm( iop ); |
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80 | |
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81 | _Objects_Allocator_lock(); |
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82 | bytes_read = (*shm->shm_object.ops->object_read)( |
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83 | &shm->shm_object, |
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84 | buffer, |
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85 | count |
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86 | ); |
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87 | _POSIX_Shm_Update_atime( shm ); |
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88 | |
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89 | _Objects_Allocator_unlock(); |
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90 | return bytes_read; |
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91 | } |
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92 | |
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93 | static int shm_ftruncate( rtems_libio_t *iop, off_t length ) |
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94 | { |
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95 | int err; |
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96 | POSIX_Shm_Control *shm = iop_to_shm( iop ); |
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97 | |
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98 | _Objects_Allocator_lock(); |
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99 | |
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100 | err = (*shm->shm_object.ops->object_resize)( &shm->shm_object, length ); |
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101 | |
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102 | if ( err != 0 ) { |
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103 | _Objects_Allocator_unlock(); |
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104 | rtems_set_errno_and_return_minus_one( err ); |
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105 | } |
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106 | |
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107 | _POSIX_Shm_Update_mtime_ctime( shm ); |
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108 | |
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109 | _Objects_Allocator_unlock(); |
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110 | return 0; |
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111 | } |
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112 | |
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113 | static int shm_close( rtems_libio_t *iop ) |
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114 | { |
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115 | POSIX_Shm_Control *shm = iop_to_shm( iop ); |
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116 | int err; |
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117 | |
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118 | err = 0; |
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119 | |
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120 | POSIX_Shm_Attempt_delete(shm); |
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121 | iop->pathinfo.node_access = NULL; |
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122 | |
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123 | if ( err != 0 ) { |
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124 | rtems_set_errno_and_return_minus_one( err ); |
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125 | } |
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126 | return 0; |
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127 | } |
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128 | |
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129 | static int shm_mmap( |
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130 | rtems_libio_t *iop, |
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131 | void** addr, |
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132 | size_t len, |
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133 | int prot, |
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134 | off_t off |
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135 | ) |
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136 | { |
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137 | POSIX_Shm_Control *shm = iop_to_shm( iop ); |
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138 | |
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139 | _Objects_Allocator_lock(); |
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140 | |
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141 | *addr = (*shm->shm_object.ops->object_mmap)( &shm->shm_object, len, prot, off); |
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142 | if ( *addr != NULL ) { |
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143 | /* Keep a reference in the shared memory to prevent its removal. */ |
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144 | ++shm->reference_count; |
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145 | |
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146 | /* Update atime */ |
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147 | _POSIX_Shm_Update_atime(shm); |
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148 | } else { |
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149 | _Objects_Allocator_unlock(); |
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150 | rtems_set_errno_and_return_minus_one( ENOMEM ); |
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151 | } |
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152 | |
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153 | _Objects_Allocator_unlock(); |
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154 | |
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155 | return 0; |
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156 | } |
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157 | |
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158 | static inline POSIX_Shm_Control *shm_allocate( |
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159 | const char *name_arg, |
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160 | size_t name_len, |
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161 | int oflag, |
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162 | mode_t mode, |
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163 | int *error |
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164 | ) |
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165 | { |
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166 | POSIX_Shm_Control *shm; |
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167 | char *name; |
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168 | struct timeval tv; |
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169 | |
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170 | /* Reject any name without a leading slash. */ |
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171 | if ( name_arg[0] != '/' ) { |
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172 | *error = EINVAL; |
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173 | return NULL; |
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174 | } |
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175 | |
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176 | /* Only create the object if requested. */ |
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177 | if ( ( oflag & O_CREAT ) != O_CREAT ) { |
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178 | *error = ENOENT; |
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179 | return NULL; |
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180 | } |
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181 | |
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182 | name = _Workspace_String_duplicate( name_arg, name_len ); |
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183 | if ( name == NULL ) { |
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184 | *error = ENOSPC; |
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185 | return NULL; |
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186 | } |
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187 | |
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188 | shm = _POSIX_Shm_Allocate_unprotected(); |
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189 | if ( shm == NULL ) { |
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190 | _Workspace_Free( name ); |
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191 | *error = ENFILE; |
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192 | return NULL; |
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193 | } |
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194 | |
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195 | gettimeofday( &tv, 0 ); |
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196 | |
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197 | shm->reference_count = 1; |
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198 | shm->shm_object.handle = NULL; |
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199 | shm->shm_object.size = 0; |
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200 | shm->shm_object.ops = &_POSIX_Shm_Object_operations; |
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201 | shm->mode = mode & ~rtems_filesystem_umask; |
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202 | shm->oflag = oflag; |
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203 | shm->uid = geteuid(); |
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204 | shm->gid = getegid(); |
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205 | shm->atime = (time_t) tv.tv_sec; |
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206 | shm->mtime = (time_t) tv.tv_sec; |
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207 | shm->ctime = (time_t) tv.tv_sec; |
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208 | |
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209 | _Objects_Open_string( &_POSIX_Shm_Information, &shm->Object, name ); |
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210 | |
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211 | return shm; |
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212 | } |
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213 | |
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214 | static inline bool shm_access_ok( POSIX_Shm_Control *shm, int oflag ) |
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215 | { |
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216 | int flags; |
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217 | |
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218 | if ( (oflag & O_ACCMODE) == O_RDONLY ) { |
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219 | flags = RTEMS_FS_PERMS_READ; |
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220 | } else { |
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221 | flags = RTEMS_FS_PERMS_WRITE; |
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222 | } |
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223 | return rtems_filesystem_check_access( flags, shm->mode, shm->uid, shm->gid ); |
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224 | } |
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225 | |
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226 | static inline int shm_check_oflag( int oflag ) |
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227 | { |
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228 | if ( ( oflag & O_ACCMODE ) != O_RDONLY && ( oflag & O_ACCMODE ) != O_RDWR ) { |
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229 | rtems_set_errno_and_return_minus_one( EACCES ); |
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230 | } |
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231 | |
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232 | if ( ( oflag & ~( O_RDONLY | O_RDWR | O_CREAT | O_EXCL | O_TRUNC ) ) != 0 ) { |
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233 | rtems_set_errno_and_return_minus_one( EACCES ); |
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234 | } |
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235 | |
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236 | if ( ( oflag & O_TRUNC ) != 0 && ( oflag & O_ACCMODE ) != O_RDWR ) { |
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237 | rtems_set_errno_and_return_minus_one( EACCES ); |
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238 | } |
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239 | return 0; |
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240 | } |
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241 | |
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242 | int shm_open( const char *name, int oflag, mode_t mode ) |
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243 | { |
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244 | int err = 0; |
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245 | int fd; |
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246 | rtems_libio_t *iop; |
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247 | POSIX_Shm_Control *shm; |
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248 | size_t len; |
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249 | Objects_Get_by_name_error obj_err; |
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250 | unsigned int flags; |
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251 | |
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252 | if ( shm_check_oflag( oflag ) != 0 ) { |
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253 | return -1; |
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254 | } |
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255 | |
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256 | iop = rtems_libio_allocate(); |
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257 | if ( iop == NULL ) { |
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258 | rtems_set_errno_and_return_minus_one( EMFILE ); |
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259 | } |
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260 | |
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261 | _Objects_Allocator_lock(); |
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262 | shm = _POSIX_Shm_Get_by_name( name, &len, &obj_err ); |
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263 | |
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264 | if ( shm == NULL ) { |
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265 | switch ( obj_err ) { |
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266 | case OBJECTS_GET_BY_NAME_INVALID_NAME: |
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267 | err = EINVAL; |
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268 | break; |
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269 | |
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270 | case OBJECTS_GET_BY_NAME_NAME_TOO_LONG: |
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271 | err = ENAMETOOLONG; |
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272 | break; |
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273 | |
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274 | case OBJECTS_GET_BY_NAME_NO_OBJECT: |
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275 | default: |
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276 | shm = shm_allocate(name, len, oflag, mode, &err); |
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277 | break; |
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278 | } |
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279 | } else { /* shm exists */ |
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280 | if ( ( oflag & ( O_EXCL | O_CREAT ) ) == ( O_EXCL | O_CREAT ) ) { |
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281 | /* Request to create failed. */ |
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282 | err = EEXIST; |
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283 | } else if ( !shm_access_ok( shm, oflag ) ) { |
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284 | err = EACCES; |
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285 | } else { |
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286 | ++shm->reference_count; |
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287 | } |
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288 | } |
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289 | _Objects_Allocator_unlock(); |
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290 | if ( err != 0 ) { |
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291 | rtems_libio_free( iop ); |
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292 | rtems_set_errno_and_return_minus_one( err ); |
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293 | } |
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294 | |
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295 | if ( oflag & O_TRUNC ) { |
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296 | err = shm_ftruncate( iop, 0 ); |
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297 | (void) err; /* ignore truncate error */ |
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298 | } |
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299 | |
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300 | fd = rtems_libio_iop_to_descriptor( iop ); |
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301 | iop->data0 = fd; |
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302 | iop->data1 = shm; |
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303 | iop->pathinfo.node_access = shm; |
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304 | iop->pathinfo.handlers = &shm_handlers; |
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305 | iop->pathinfo.mt_entry = &rtems_filesystem_null_mt_entry; |
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306 | rtems_filesystem_location_add_to_mt_entry( &iop->pathinfo ); |
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307 | |
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308 | flags = LIBIO_FLAGS_OPEN | LIBIO_FLAGS_CLOSE_ON_EXEC; |
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309 | if ( (oflag & O_ACCMODE) == O_RDONLY ) { |
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310 | flags |= LIBIO_FLAGS_READ; |
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311 | } else { |
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312 | flags |= LIBIO_FLAGS_READ_WRITE; |
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313 | } |
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314 | |
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315 | rtems_libio_iop_flags_set( iop, flags ); |
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316 | |
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317 | return fd; |
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318 | } |
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319 | |
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320 | static const rtems_filesystem_file_handlers_r shm_handlers = { |
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321 | .open_h = rtems_filesystem_default_open, |
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322 | .close_h = shm_close, |
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323 | .read_h = shm_read, |
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324 | .write_h = rtems_filesystem_default_write, |
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325 | .ioctl_h = rtems_filesystem_default_ioctl, |
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326 | .lseek_h = rtems_filesystem_default_lseek, |
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327 | .fstat_h = shm_fstat, |
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328 | .ftruncate_h = shm_ftruncate, |
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329 | .fsync_h = rtems_filesystem_default_fsync_or_fdatasync, |
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330 | .fdatasync_h = rtems_filesystem_default_fsync_or_fdatasync, |
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331 | .fcntl_h = rtems_filesystem_default_fcntl, |
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332 | .kqfilter_h = rtems_filesystem_default_kqfilter, |
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333 | .mmap_h = shm_mmap, |
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334 | .poll_h = rtems_filesystem_default_poll, |
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335 | .readv_h = rtems_filesystem_default_readv, |
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336 | .writev_h = rtems_filesystem_default_writev |
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337 | }; |
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338 | |
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339 | static void _POSIX_Shm_Manager_initialization( void ) |
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340 | { |
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341 | _Objects_Initialize_information( &_POSIX_Shm_Information ); |
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342 | } |
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343 | |
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344 | RTEMS_SYSINIT_ITEM( |
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345 | _POSIX_Shm_Manager_initialization, |
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346 | RTEMS_SYSINIT_POSIX_SHM, |
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347 | RTEMS_SYSINIT_ORDER_MIDDLE |
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348 | ); |
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