1 | /** |
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2 | * @file |
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3 | * |
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4 | * @brief System Generates Signal for process after realtime seconds elapsed |
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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 | * 3.4.1 Schedule Alarm, P1003.1b-1993, p. 79 |
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10 | */ |
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11 | |
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12 | /* COPYRIGHT (c) 1989-2013. |
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13 | * On-Line Applications Research Corporation (OAR). |
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14 | * |
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15 | * The license and distribution terms for this file may be |
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16 | * found in the file LICENSE in this distribution or at |
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17 | * http://www.rtems.org/license/LICENSE. |
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18 | */ |
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19 | |
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20 | #if HAVE_CONFIG_H |
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21 | #include "config.h" |
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22 | #endif |
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23 | |
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24 | #include <unistd.h> |
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25 | #include <signal.h> |
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26 | |
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27 | #include <rtems/score/todimpl.h> |
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28 | #include <rtems/score/watchdogimpl.h> |
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29 | |
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30 | ISR_LOCK_DEFINE( static, _POSIX_signals_Alarm_lock, "POSIX Alarm" ) |
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31 | |
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32 | static void _POSIX_signals_Alarm_TSR( Watchdog_Control *the_watchdog ) |
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33 | { |
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34 | int status; |
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35 | |
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36 | status = kill( getpid(), SIGALRM ); |
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37 | |
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38 | #if defined(RTEMS_DEBUG) |
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39 | /* |
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40 | * There is no reason to think this might fail but we should be |
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41 | * cautious. |
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42 | */ |
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43 | _Assert(status == 0); |
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44 | #else |
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45 | (void) status; |
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46 | #endif |
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47 | } |
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48 | |
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49 | static Watchdog_Control _POSIX_signals_Alarm_watchdog = WATCHDOG_INITIALIZER( |
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50 | _POSIX_signals_Alarm_TSR |
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51 | ); |
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52 | |
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53 | unsigned int alarm( |
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54 | unsigned int seconds |
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55 | ) |
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56 | { |
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57 | unsigned int remaining; |
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58 | Watchdog_Control *the_watchdog; |
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59 | ISR_lock_Context lock_context; |
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60 | ISR_lock_Context lock_context2; |
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61 | Per_CPU_Control *cpu; |
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62 | uint64_t now; |
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63 | uint32_t ticks_per_second; |
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64 | uint32_t ticks; |
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65 | |
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66 | the_watchdog = &_POSIX_signals_Alarm_watchdog; |
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67 | ticks_per_second = TOD_TICKS_PER_SECOND; |
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68 | ticks = seconds * ticks_per_second; |
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69 | |
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70 | _ISR_lock_ISR_disable_and_acquire( |
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71 | &_POSIX_signals_Alarm_lock, |
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72 | &lock_context |
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73 | ); |
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74 | |
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75 | cpu = _Watchdog_Get_CPU( the_watchdog ); |
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76 | _Watchdog_Per_CPU_acquire_critical( cpu, &lock_context2 ); |
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77 | now = cpu->Watchdog.ticks; |
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78 | |
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79 | remaining = (unsigned long) _Watchdog_Cancel( |
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80 | &cpu->Watchdog.Header[ PER_CPU_WATCHDOG_MONOTONIC ], |
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81 | the_watchdog, |
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82 | now |
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83 | ); |
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84 | |
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85 | if ( ticks != 0 ) { |
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86 | _Watchdog_Insert( |
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87 | &cpu->Watchdog.Header[ PER_CPU_WATCHDOG_MONOTONIC ], |
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88 | the_watchdog, |
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89 | now + ticks |
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90 | ); |
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91 | } |
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92 | |
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93 | _Watchdog_Per_CPU_release_critical( cpu, &lock_context2 ); |
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94 | _ISR_lock_Release_and_ISR_enable( |
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95 | &_POSIX_signals_Alarm_lock, |
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96 | &lock_context |
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97 | ); |
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98 | |
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99 | return ( remaining + ticks_per_second - 1 ) / ticks_per_second; |
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100 | } |
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