1 | /* |
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2 | * Object Handler |
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3 | * |
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4 | * |
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5 | * COPYRIGHT (c) 1989-1999. |
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6 | * On-Line Applications Research Corporation (OAR). |
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7 | * |
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8 | * The license and distribution terms for this file may be |
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9 | * found in the file LICENSE in this distribution or at |
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10 | * http://www.rtems.com/license/LICENSE. |
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11 | */ |
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12 | |
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13 | #if HAVE_CONFIG_H |
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14 | #include "config.h" |
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15 | #endif |
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16 | |
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17 | #include <rtems/system.h> |
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18 | #include <rtems/score/address.h> |
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19 | #include <rtems/score/chain.h> |
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20 | #include <rtems/score/object.h> |
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21 | #if defined(RTEMS_MULTIPROCESSING) |
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22 | #include <rtems/score/objectmp.h> |
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23 | #endif |
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24 | #include <rtems/score/thread.h> |
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25 | #include <rtems/score/wkspace.h> |
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26 | #include <rtems/score/sysstate.h> |
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27 | #include <rtems/score/isr.h> |
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28 | |
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29 | /* |
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30 | * _Objects_Get |
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31 | * |
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32 | * This routine sets the object pointer for the given |
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33 | * object id based on the given object information structure. |
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34 | * |
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35 | * Input parameters: |
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36 | * information - pointer to entry in table for this class |
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37 | * id - object id to search for |
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38 | * location - address of where to store the location |
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39 | * |
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40 | * Output parameters: |
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41 | * returns - address of object if local |
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42 | * location - one of the following: |
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43 | * OBJECTS_ERROR - invalid object ID |
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44 | * OBJECTS_REMOTE - remote object |
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45 | * OBJECTS_LOCAL - local object |
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46 | */ |
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47 | |
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48 | Objects_Control *_Objects_Get( |
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49 | Objects_Information *information, |
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50 | Objects_Id id, |
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51 | Objects_Locations *location |
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52 | ) |
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53 | { |
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54 | Objects_Control *the_object; |
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55 | uint32_t index; |
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56 | |
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57 | /* |
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58 | * Extract the index portion of an Id in a way that produces a valid |
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59 | * index for objects within this class and an invalid value for objects |
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60 | * outside this class. |
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61 | * |
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62 | * If the Id matches the api, class, and node but index portion is 0, |
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63 | * then the subtraction will underflow and the addition of 1 will |
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64 | * result in a 0 index. The zeroth element in the local_table is |
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65 | * always NULL. |
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66 | * |
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67 | * If the Id is valid but the object has not been created yet, then |
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68 | * the local_table entry will be NULL. |
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69 | */ |
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70 | index = id - information->minimum_id + 1; |
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71 | |
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72 | /* |
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73 | * If the index is less than maximum, then it is OK to use it to |
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74 | * index into the local_table array. |
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75 | */ |
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76 | if ( index <= information->maximum ) { |
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77 | _Thread_Disable_dispatch(); |
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78 | if ( (the_object = information->local_table[ index ]) != NULL ) { |
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79 | *location = OBJECTS_LOCAL; |
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80 | return the_object; |
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81 | } |
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82 | |
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83 | /* |
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84 | * Valid Id for this API, Class and Node but the object has not |
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85 | * been allocated yet. |
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86 | */ |
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87 | _Thread_Enable_dispatch(); |
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88 | *location = OBJECTS_ERROR; |
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89 | return NULL; |
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90 | } |
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91 | |
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92 | /* |
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93 | * Object Id is not within this API and Class on this node. So |
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94 | * it may be global in a multiprocessing system. But it is clearly |
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95 | * invalid on a single processor system. |
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96 | */ |
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97 | *location = OBJECTS_ERROR; |
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98 | |
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99 | #if defined(RTEMS_MULTIPROCESSING) |
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100 | _Objects_MP_Is_remote( information, id, location, &the_object ); |
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101 | return the_object; |
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102 | #else |
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103 | return NULL; |
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104 | #endif |
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105 | } |
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