| [4] | 1 | /* This library provides generic watchdog timer management functionality.
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| 2 | * The functions operate on a timer queue provided by the caller. Note that
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| 3 | * the timers must use absolute time to allow sorting. The library provides:
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| 4 | *
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| 5 | * tmrs_settimer: (re)set a new watchdog timer in the timers queue
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| 6 | * tmrs_clrtimer: remove a timer from both the timers queue
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| 7 | * tmrs_exptimers: check for expired timers and run watchdog functions
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| 8 | *
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| 9 | * Author:
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| 10 | * Jorrit N. Herder <jnherder@cs.vu.nl>
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| 11 | * Adapted from tmr_settimer and tmr_clrtimer in src/kernel/clock.c.
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| 12 | * Last modified: September 30, 2004.
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| 13 | */
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| 14 |
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| 15 | #ifndef _TIMERS_H
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| 16 | #define _TIMERS_H
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| 17 |
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| 18 | #include <limits.h>
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| 19 | #include <sys/types.h>
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| 20 |
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| 21 | struct timer;
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| 22 | typedef void (*tmr_func_t)(struct timer *tp);
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| 23 | typedef union { int ta_int; long ta_long; void *ta_ptr; } tmr_arg_t;
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| 24 |
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| 25 | /* A timer_t variable must be declare for each distinct timer to be used.
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| 26 | * The timers watchdog function and expiration time are automatically set
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| 27 | * by the library function tmrs_settimer, but its argument is not.
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| 28 | */
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| 29 | typedef struct timer
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| 30 | {
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| 31 | struct timer *tmr_next; /* next in a timer chain */
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| 32 | clock_t tmr_exp_time; /* expiration time */
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| 33 | tmr_func_t tmr_func; /* function to call when expired */
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| 34 | tmr_arg_t tmr_arg; /* random argument */
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| 35 | } timer_t;
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| 36 |
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| 37 | /* Used when the timer is not active. */
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| 38 | #define TMR_NEVER ((clock_t) -1 < 0) ? ((clock_t) LONG_MAX) : ((clock_t) -1)
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| 39 | #undef TMR_NEVER
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| 40 | #define TMR_NEVER ((clock_t) LONG_MAX)
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| 41 |
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| 42 | /* These definitions can be used to set or get data from a timer variable. */
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| 43 | #define tmr_arg(tp) (&(tp)->tmr_arg)
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| 44 | #define tmr_exp_time(tp) (&(tp)->tmr_exp_time)
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| 45 |
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| 46 | /* Timers should be initialized once before they are being used. Be careful
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| 47 | * not to reinitialize a timer that is in a list of timers, or the chain
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| 48 | * will be broken.
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| 49 | */
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| 50 | #define tmr_inittimer(tp) (void)((tp)->tmr_exp_time = TMR_NEVER, \
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| 51 | (tp)->tmr_next = NULL)
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| 52 |
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| 53 | /* The following generic timer management functions are available. They
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| 54 | * can be used to operate on the lists of timers. Adding a timer to a list
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| 55 | * automatically takes care of removing it.
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| 56 | */
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| 57 | _PROTOTYPE( clock_t tmrs_clrtimer, (timer_t **tmrs, timer_t *tp, clock_t *new_head) );
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| 58 | _PROTOTYPE( void tmrs_exptimers, (timer_t **tmrs, clock_t now, clock_t *new_head) );
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| 59 | _PROTOTYPE( clock_t tmrs_settimer, (timer_t **tmrs, timer_t *tp,
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| 60 | clock_t exp_time, tmr_func_t watchdog, clock_t *new_head) );
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| 61 |
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| 62 | #endif /* _TIMERS_H */
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| 63 |
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