1 | /** |
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2 | * @file |
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3 | * |
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4 | * @brief Receive Message from Message Queue |
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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 | * NOTE: The structure of the routines is identical to that of POSIX |
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10 | * Message_queues to leave the option of having unnamed message |
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11 | * queues at a future date. They are currently not part of the |
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12 | * POSIX standard but unnamed message_queues are. This is also |
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13 | * the reason for the apparently unnecessary tracking of |
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14 | * the process_shared attribute. [In addition to the fact that |
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15 | * it would be trivial to add pshared to the mq_attr structure |
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16 | * and have process private message queues.] |
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17 | * |
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18 | * This code ignores the O_RDONLY/O_WRONLY/O_RDWR flag at open |
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19 | * time. |
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20 | */ |
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21 | |
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22 | /* |
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23 | * COPYRIGHT (c) 1989-2008. |
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24 | * On-Line Applications Research Corporation (OAR). |
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25 | * |
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26 | * The license and distribution terms for this file may be |
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27 | * found in the file LICENSE in this distribution or at |
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28 | * http://www.rtems.org/license/LICENSE. |
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29 | */ |
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30 | |
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31 | #if HAVE_CONFIG_H |
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32 | #include "config.h" |
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33 | #endif |
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34 | |
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35 | #include <stdarg.h> |
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36 | |
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37 | #include <pthread.h> |
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38 | #include <limits.h> |
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39 | #include <errno.h> |
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40 | #include <fcntl.h> |
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41 | #include <mqueue.h> |
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42 | |
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43 | #include <rtems/system.h> |
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44 | #include <rtems/score/watchdog.h> |
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45 | #include <rtems/seterr.h> |
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46 | #include <rtems/posix/mqueueimpl.h> |
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47 | #include <rtems/posix/time.h> |
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48 | |
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49 | /* |
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50 | * 15.2.5 Receive a Message From a Message Queue, P1003.1b-1993, p. 279 |
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51 | * |
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52 | * NOTE: P1003.4b/D8, p. 45 adds mq_timedreceive(). |
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53 | */ |
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54 | |
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55 | ssize_t mq_timedreceive( |
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56 | mqd_t mqdes, |
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57 | char *__restrict msg_ptr, |
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58 | size_t msg_len, |
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59 | unsigned int *__restrict msg_prio, |
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60 | const struct timespec *__restrict abstime |
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61 | ) |
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62 | { |
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63 | Watchdog_Interval ticks; |
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64 | bool do_wait = true; |
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65 | POSIX_Absolute_timeout_conversion_results_t status; |
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66 | |
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67 | /* |
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68 | * POSIX requires that blocking calls with timeouts that take |
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69 | * an absolute timeout must ignore issues with the absolute |
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70 | * time provided if the operation would otherwise succeed. |
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71 | * So we check the abstime provided, and hold on to whether it |
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72 | * is valid or not. If it isn't correct and in the future, |
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73 | * then we do a polling operation and convert the UNSATISFIED |
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74 | * status into the appropriate error. |
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75 | * |
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76 | * If the status is POSIX_ABSOLUTE_TIMEOUT_INVALID, |
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77 | * POSIX_ABSOLUTE_TIMEOUT_IS_IN_PAST, or POSIX_ABSOLUTE_TIMEOUT_IS_NOW, |
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78 | * then we should not wait. |
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79 | */ |
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80 | status = _POSIX_Absolute_timeout_to_ticks( abstime, &ticks ); |
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81 | if ( status != POSIX_ABSOLUTE_TIMEOUT_IS_IN_FUTURE ) |
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82 | do_wait = false; |
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83 | |
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84 | return _POSIX_Message_queue_Receive_support( |
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85 | mqdes, |
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86 | msg_ptr, |
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87 | msg_len, |
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88 | msg_prio, |
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89 | do_wait, |
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90 | ticks |
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91 | ); |
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92 | } |
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