1 | /** |
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2 | * @file |
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3 | * |
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4 | * @brief Allocate resources to use the read-write lock and Initialize it |
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5 | * @ingroup POSIXAPI |
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6 | */ |
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7 | |
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8 | /* |
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9 | * POSIX RWLock Manager -- Destroy a RWLock Instance |
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10 | * |
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11 | * COPYRIGHT (c) 1989-2006. |
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12 | * On-Line Applications Research Corporation (OAR). |
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13 | * |
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14 | * The license and distribution terms for this file may be |
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15 | * found in the file LICENSE in this distribution or at |
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16 | * http://www.rtems.org/license/LICENSE. |
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17 | */ |
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18 | |
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19 | #if HAVE_CONFIG_H |
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20 | #include "config.h" |
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21 | #endif |
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22 | |
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23 | #include <pthread.h> |
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24 | #include <errno.h> |
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25 | |
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26 | #include <rtems/posix/rwlockimpl.h> |
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27 | #include <rtems/score/apimutex.h> |
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28 | |
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29 | static bool _POSIX_RWLock_Check_id_and_auto_init( |
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30 | pthread_mutex_t *rwlock, |
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31 | Objects_Locations *location |
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32 | ) |
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33 | { |
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34 | if ( rwlock == NULL ) { |
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35 | *location = OBJECTS_ERROR; |
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36 | |
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37 | return false; |
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38 | } |
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39 | |
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40 | if ( *rwlock == PTHREAD_RWLOCK_INITIALIZER ) { |
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41 | int eno; |
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42 | |
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43 | _Once_Lock(); |
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44 | |
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45 | if ( *rwlock == PTHREAD_RWLOCK_INITIALIZER ) { |
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46 | eno = pthread_rwlock_init( rwlock, NULL ); |
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47 | } else { |
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48 | eno = 0; |
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49 | } |
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50 | |
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51 | _Once_Unlock(); |
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52 | |
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53 | if ( eno != 0 ) { |
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54 | *location = OBJECTS_ERROR; |
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55 | |
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56 | return false; |
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57 | } |
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58 | } |
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59 | |
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60 | return true; |
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61 | } |
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62 | |
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63 | POSIX_RWLock_Control *_POSIX_RWLock_Get( |
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64 | pthread_rwlock_t *rwlock, |
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65 | Objects_Locations *location |
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66 | ) |
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67 | { |
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68 | if ( !_POSIX_RWLock_Check_id_and_auto_init( rwlock, location ) ) { |
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69 | return NULL; |
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70 | } |
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71 | |
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72 | return (POSIX_RWLock_Control *) _Objects_Get( |
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73 | &_POSIX_RWLock_Information, |
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74 | *rwlock, |
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75 | location |
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76 | ); |
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77 | } |
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78 | |
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79 | /* |
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80 | * pthread_rwlock_init |
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81 | * |
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82 | * This directive creates a rwlock. A rwlock id is returned. |
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83 | * |
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84 | * Input parameters: |
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85 | * rwlock - pointer to rwlock id |
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86 | * attr - rwlock attributes |
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87 | * |
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88 | * Output parameters: |
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89 | * rwlock - rwlock id |
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90 | * 0 - if successful |
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91 | * error code - if unsuccessful |
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92 | */ |
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93 | |
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94 | int pthread_rwlock_init( |
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95 | pthread_rwlock_t *rwlock, |
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96 | const pthread_rwlockattr_t *attr |
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97 | ) |
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98 | { |
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99 | POSIX_RWLock_Control *the_rwlock; |
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100 | CORE_RWLock_Attributes the_attributes; |
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101 | pthread_rwlockattr_t default_attr; |
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102 | const pthread_rwlockattr_t *the_attr; |
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103 | |
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104 | /* |
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105 | * Error check parameters |
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106 | */ |
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107 | if ( !rwlock ) |
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108 | return EINVAL; |
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109 | |
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110 | /* |
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111 | * If the user passed in NULL, use the default attributes |
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112 | */ |
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113 | if ( attr ) { |
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114 | the_attr = attr; |
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115 | } else { |
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116 | (void) pthread_rwlockattr_init( &default_attr ); |
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117 | the_attr = &default_attr; |
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118 | } |
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119 | |
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120 | /* |
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121 | * Now start error checking the attributes that we are going to use |
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122 | */ |
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123 | if ( !the_attr->is_initialized ) |
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124 | return EINVAL; |
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125 | |
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126 | switch ( the_attr->process_shared ) { |
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127 | case PTHREAD_PROCESS_PRIVATE: /* only supported values */ |
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128 | break; |
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129 | case PTHREAD_PROCESS_SHARED: |
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130 | default: |
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131 | return EINVAL; |
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132 | } |
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133 | |
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134 | /* |
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135 | * Convert from POSIX attributes to Core RWLock attributes |
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136 | * |
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137 | * NOTE: Currently there are no core rwlock attributes |
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138 | */ |
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139 | _CORE_RWLock_Initialize_attributes( &the_attributes ); |
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140 | |
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141 | the_rwlock = _POSIX_RWLock_Allocate(); |
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142 | |
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143 | if ( !the_rwlock ) { |
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144 | _Objects_Allocator_unlock(); |
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145 | return EAGAIN; |
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146 | } |
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147 | |
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148 | _CORE_RWLock_Initialize( &the_rwlock->RWLock, &the_attributes ); |
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149 | |
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150 | _Objects_Open_u32( |
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151 | &_POSIX_RWLock_Information, |
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152 | &the_rwlock->Object, |
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153 | 0 |
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154 | ); |
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155 | |
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156 | *rwlock = the_rwlock->Object.id; |
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157 | |
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158 | _Objects_Allocator_unlock(); |
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159 | return 0; |
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160 | } |
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