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Arquivotheca.Solaris-2.5/uts/common/os/callb.c
seta75D 7c4988eac0 Init
2021-10-11 19:38:01 -03:00

272 lines
6.1 KiB
C
Executable File

/*
* Copyright (c) 1993 by Sun Microsystems, Inc.
*/
#pragma ident "@(#)callb.c 1.6 94/03/31 SMI"
#include <sys/param.h>
#include <sys/t_lock.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/sysmacros.h>
#include <sys/systm.h>
#include <sys/cpuvar.h>
#include <sys/user.h>
#include <sys/proc.h>
#include <sys/callb.h>
#include <sys/kmem.h>
#include <sys/cmn_err.h>
#include <sys/map.h>
#include <sys/swap.h>
#include <sys/vmsystm.h>
#include <sys/class.h>
#include <sys/debug.h>
#define CB_MAXNAME 16
/*
* The callb mechanism provides generic event scheduling/echoing.
* A callb function is registered and called on behalf of the event.
*/
typedef struct callb {
struct callb *c_next; /* next in class or on freelist */
char c_flag; /* info about the callb state */
char c_class; /* this callb's class */
void (*c_func)(); /* function to call */
void *c_arg; /* arg to c_func */
kcondvar_t c_done_cv; /* signal callb completion */
char c_name[CB_MAXNAME]; /* debug:max name len for a callb */
} callb_t;
/*
* callb c_flag bitmap definitions
*/
#define CALLB_FREE 0x0
#define CALLB_TAKEN 0x1
#define CALLB_EXECUTING 0x2
/*
* Basic structure for a callb table.
* All callbs are organized into different class groups described
* by ct_class array.
* The callbs within a class are single-linked and normally run by a
* serial execution.
*/
typedef struct callb_table {
kmutex_t ct_lock; /* protect all callb states */
callb_t *ct_freelist; /* free callb structures */
int ct_ncallb; /* num of callbs allocated */
callb_t *ct_first_cb[NCBCLASS]; /* ptr to 1st callb in a class */
} callb_table_t;
static callb_table_t callb_table; /* system level callback table */
static callb_table_t *ct = &callb_table;
/*
* Init all callb tables in the system.
*/
void
callb_init()
{
mutex_init(&callb_table.ct_lock, "callb lock", MUTEX_DEFAULT, NULL);
}
/*
* callout_add() is called to register func() be called later.
*/
callb_id_t
callb_add(void (*func)(void *arg, int code), void *arg, int class, char *name)
{
callb_t *cp;
ASSERT(class < NCBCLASS);
mutex_enter(&ct->ct_lock);
if ((cp = ct->ct_freelist) == NULL) {
ct->ct_ncallb++;
cp = (callb_t *)kmem_zalloc(sizeof (callb_t), KM_SLEEP);
}
ct->ct_freelist = cp->c_next;
cp->c_func = func;
cp->c_arg = arg;
cp->c_class = class;
cp->c_flag |= CALLB_TAKEN;
ASSERT(strlen(name) <= CB_MAXNAME);
strcpy(cp->c_name, name);
/*
* Insert the new callb at the head of its class list.
*/
cp->c_next = ct->ct_first_cb[class];
ct->ct_first_cb[class] = cp;
mutex_exit(&ct->ct_lock);
return ((callb_id_t)cp);
}
/*
* callout_delete() is called to remove an entry identified by id
* that was originally placed there by a call to callout_add().
* return -1 if fail to delete a callb entry
* otherwsie return 0.
*/
int
callb_delete(callb_id_t id)
{
callb_t **pp;
callb_t *me = (callb_t *)id;
mutex_enter(&ct->ct_lock);
for (;;) {
pp = &ct->ct_first_cb[me->c_class];
while (*pp != NULL && *pp != me)
pp = &(*pp)->c_next;
#ifdef DEBUG
if (*pp != me) {
cmn_err(CE_WARN,
"callb delete bogus entry 0x%x", (int)me);
mutex_exit(&ct->ct_lock);
return (-1);
}
#endif DEBUG
/*
* It is not allowed to delete a callb in the middle of
* executing otherwise, the callb_execute() will be confused.
*/
if (!(me->c_flag & CALLB_EXECUTING))
break;
cv_wait(&me->c_done_cv, &ct->ct_lock);
}
/* relink the class list */
*pp = me->c_next;
/* clean up myself and return the free callb to the head of freelist */
me->c_flag = CALLB_FREE;
me->c_next = ct->ct_freelist;
ct->ct_freelist = me;
mutex_exit(&ct->ct_lock);
return (0);
}
/*
* mep: run callb pointed by mep;
* code: optional argument for the callb functions.
*/
void
callb_execute(callb_id_t id, int code)
{
callb_t *cp;
callb_t *me = (callb_t *)id;
mutex_enter(&ct->ct_lock);
#ifdef DEBUG /* validate the id */
cp = ct->ct_first_cb[me->c_class];
while (cp != NULL && cp != me)
cp = cp->c_next;
if (cp == NULL) {
cmn_err(CE_WARN, "callb executing bogus entry");
mutex_exit(&ct->ct_lock);
return;
}
#endif DEBUG
while (me->c_flag & CALLB_EXECUTING) {
cv_wait(&me->c_done_cv, &ct->ct_lock);
/*
* return if the callb is deleted while we're sleeping
*/
if (me->c_flag == CALLB_FREE) {
mutex_exit(&ct->ct_lock);
return;
}
}
me->c_flag |= CALLB_EXECUTING;
mutex_exit(&ct->ct_lock);
(*me->c_func)(me->c_arg, code);
mutex_enter(&ct->ct_lock);
me->c_flag &= ~CALLB_EXECUTING;
cv_broadcast(&me->c_done_cv);
mutex_exit(&ct->ct_lock);
}
/*
* class: indicates to execute all callbs in the same class;
* code: optional argument for the callb functions.
*/
void
callb_execute_class(int class, int code)
{
callb_t *cp;
ASSERT(class < NCBCLASS);
mutex_enter(&ct->ct_lock);
for (cp = ct->ct_first_cb[class]; cp != NULL; cp = cp->c_next) {
while (cp->c_flag & CALLB_EXECUTING)
cv_wait(&cp->c_done_cv, &ct->ct_lock);
/*
* cont if the callb is deleted while we're sleeping
*/
if (cp->c_flag == CALLB_FREE)
continue;
cp->c_flag |= CALLB_EXECUTING;
#ifdef CALLB_DEBUG
printf("callb_execute: name=%s func=%x arg=%x\n",
cp->c_name, cp->c_func, cp->c_arg);
#endif CALLB_DEBUG
mutex_exit(&ct->ct_lock);
(*cp->c_func)(cp->c_arg, code);
mutex_enter(&ct->ct_lock);
cp->c_flag &= ~CALLB_EXECUTING;
cv_broadcast(&cp->c_done_cv);
}
mutex_exit(&ct->ct_lock);
}
/*
* callers make sure no recursive entries to this func.
* dp->cc_lockp is registered by callb_add to protect callb_cpr_t structure.
*
* Note that this is a generic callback handler for daemon CPR and
* should NOT be changed to accommondate any specific requirement in a daemon.
* Individual daemons that require changes to the handler shall write
* callback routines in their own daemon modules.
*/
void
callb_generic_cpr(void *arg, int code)
{
callb_cpr_t *cp = (callb_cpr_t *)arg;
mutex_enter(cp->cc_lockp);
switch (code) {
case CB_CODE_CPR_CHKPT:
cp->cc_events |= CALLB_CPR_START;
while (!(cp->cc_events & CALLB_CPR_SAFE))
cv_wait(&cp->cc_callb_cv, cp->cc_lockp);
break;
case CB_CODE_CPR_RESUME:
cp->cc_events &= ~CALLB_CPR_START;
cv_signal(&cp->cc_stop_cv);
break;
}
mutex_exit(cp->cc_lockp);
}