1 | /** |
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2 | * @file |
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3 | * |
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4 | * @brief Function applies a Write lock to RWLock referenced by rwlock |
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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 -- Attempt to Obtain a Write Lock on a RWLock Instance |
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10 | * |
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11 | * COPYRIGHT (c) 1989-2008. |
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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 <rtems/posix/rwlockimpl.h> |
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24 | #include <rtems/posix/posixapi.h> |
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25 | #include <rtems/score/todimpl.h> |
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26 | |
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27 | int pthread_rwlock_timedwrlock( |
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28 | pthread_rwlock_t *rwlock, |
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29 | const struct timespec *abstime |
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30 | ) |
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31 | { |
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32 | POSIX_RWLock_Control *the_rwlock; |
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33 | Thread_queue_Context queue_context; |
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34 | Watchdog_Interval ticks; |
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35 | bool do_wait; |
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36 | TOD_Absolute_timeout_conversion_results timeout_status; |
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37 | Status_Control status; |
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38 | |
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39 | /* |
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40 | * POSIX requires that blocking calls with timeouts that take |
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41 | * an absolute timeout must ignore issues with the absolute |
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42 | * time provided if the operation would otherwise succeed. |
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43 | * So we check the abstime provided, and hold on to whether it |
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44 | * is valid or not. If it isn't correct and in the future, |
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45 | * then we do a polling operation and convert the STATUS_UNAVAILABLE |
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46 | * status into the appropriate error. |
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47 | * |
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48 | * If the timeout status is TOD_ABSOLUTE_TIMEOUT_INVALID, |
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49 | * TOD_ABSOLUTE_TIMEOUT_IS_IN_PAST, or TOD_ABSOLUTE_TIMEOUT_IS_NOW, |
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50 | * then we should not wait. |
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51 | */ |
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52 | timeout_status = _TOD_Absolute_timeout_to_ticks( abstime, &ticks ); |
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53 | do_wait = ( timeout_status == TOD_ABSOLUTE_TIMEOUT_IS_IN_FUTURE ); |
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54 | |
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55 | the_rwlock = _POSIX_RWLock_Get( rwlock, &queue_context ); |
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56 | |
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57 | if ( the_rwlock == NULL ) { |
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58 | return EINVAL; |
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59 | } |
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60 | |
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61 | _Thread_queue_Context_set_relative_timeout( &queue_context, ticks ); |
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62 | status = _CORE_RWLock_Seize_for_writing( |
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63 | &the_rwlock->RWLock, |
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64 | _Thread_Executing, |
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65 | do_wait, |
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66 | &queue_context |
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67 | ); |
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68 | |
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69 | if ( !do_wait && status == STATUS_UNAVAILABLE ) { |
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70 | if ( timeout_status == TOD_ABSOLUTE_TIMEOUT_INVALID ) { |
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71 | return EINVAL; |
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72 | } |
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73 | |
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74 | if ( |
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75 | timeout_status == TOD_ABSOLUTE_TIMEOUT_IS_IN_PAST |
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76 | || timeout_status == TOD_ABSOLUTE_TIMEOUT_IS_NOW |
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77 | ) { |
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78 | return ETIMEDOUT; |
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79 | } |
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80 | } |
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81 | |
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82 | return _POSIX_Get_error( status ); |
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83 | } |
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