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epics-base/src/libCom/fdmgr.c
1992-05-08 19:14:38 +00:00

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/*
*
* F D M G R . C
*
* Author Jeffrey O. Hill
* hill@luke.lanl.gov
* 505 665 1831
*
*
* A manager for use with the UNIX system call select
*
*
*
*
* History
* .01 joh 071890 written - uses lots of memory and could be
* slow with many fds
* .02 joh 110990 Added alarms
* .03 joh 110990 now uses the number of fd the system is
* configured for- a linked list would be faster
* and use less memory
* .04 joh 050291 Now uses a linked list entry for each fd
* .05 rac 062891 get <types> and <time> from <sys/
* .06 joh 050792 ported to V5 vxWorks now that wrs provides
* a fully funtional select()
* .07 joh 050792 allroutines now return status
*
*
*
*/
#if defined(vxWorks)
# include <vxWorks.h>
# include <vxTypes.h>
# include <systime.h>
# include <errno.h>
# include <fast_lock.h>
#if 0
# include <stdioLib.h>
#endif
#elif defined(UNIX)
# include <sys/types.h>
# include <sys/time.h>
# include <errno.h>
#if 0
# include <stdio.h>
#endif
#else
@@@@ Dont compile in this case @@@@
#endif
#ifndef INClstLibh
#include <lstLib.h>
#endif
#ifndef TRUE
#define TRUE 1
#endif
#ifndef FALSE
#define FALSE 0
#endif
#ifndef OK
#define OK 0
#endif
#ifndef ERROR
#define ERROR (-1)
#endif
#ifndef NULL
#define NULL 0
#endif
#ifndef max
#define max(x, y) (((x) < (y)) ? (y) : (x))
#endif
struct fd_handler{
void (*pfunc)();
void *param;
};
typedef struct{
NODE node;
int fd;
struct fd_handler rd;
struct fd_handler wt;
struct fd_handler excp;
int delete_pending;
}fdentry;
typedef struct{
unsigned maxfd;
LIST fdentry_list;
LIST fdentry_in_use_list;
LIST fdentry_free_list;
LIST alarm_list;
LIST expired_alarm_list;
LIST free_alarm_list;
int select_tmo;
# if defined(vxWorks)
FAST_LOCK lock;
FAST_LOCK fdmgr_pend_event_lock;
unsigned clk_rate; /* ticks per sec */
# elif defined(UNIX)
unsigned fdmgr_pend_event_in_use;
# endif
fd_set readch;
fd_set writech;
fd_set excpch;
}fdctx;
typedef struct{
NODE node;
struct timeval t;
void (*func)();
void *param;
}alarm;
#if defined(vxWorks)
# define LOCK(pfdctx)(PFDCTX) FASTLOCK(&(PFDCTX)->lock)
# define UNLOCK(pfdctx)(PFDCTX) FASTUNLOCK(&(PFDCTX)->lock)
# define LOCK_FDMGR_PEND_EVENT(PFDCTX) \
FASTLOCK(&(PFDCTX)->fdmgr_pend_event_lock)
# define UNLOCK_FDMGR_PEND_EVENT(PFDCTX) \
FASTLOCK(&(PFDCTX)->fdmgr_pend_event_lock)
# define printf logMsg
# define fdmgr_gettimeval fdmgr_vxWorks_gettimeval
#elif defined(UNIX)
# define LOCK(PFDCTX)
# define UNLOCK(PFDCTX)
# define LOCK_FDMGR_PEND_EVENT(PFDCTX) \
{ \
if((PFDCTX)->fdmgr_pend_event_in_use){ \
printf("Double invocation of fdmgr_pend_event()\n"); \
abort(); \
} \
(PFDCTX)->fdmgr_pend_event_in_use++; \
}
# define UNLOCK_FDMGR_PEND_EVENT(PFDCTX) \
{(PFDCTX)->fdmgr_pend_event_in_use--;}
# define fdmgr_gettimeval fdmgr_UNIX_gettimeval
#else
@@@@ dont compile in this case @@@@
#endif
#define USEC_PER_SEC 1000000
void select_alarm();
void fdmgr_finish_off_fdentry();
#if defined(vxWorks)
# define abort(A) taskSuspend(taskIdSelf())
#endif
/*
*
* fdmgr_init()
*
*/
fdctx
*fdmgr_init()
{
fdctx *pfdctx;
pfdctx = (fdctx *) calloc(1, sizeof(fdctx));
/*
* returns NULL if unsuccessfull
*/
return pfdctx;
}
/*
*
* fdmgr_add_timeout()
*
*
*/
alarm
*fdmgr_add_timeout(pfdctx, ptimeout, func ,param)
fdctx *pfdctx;
struct timeval *ptimeout;
void (*func)();
void *param;
{
alarm *palarm=NULL;
alarm *pa;
struct timeval t;
int status;
LOCK(pfdctx);
palarm = (alarm *) lstGet(&pfdctx->free_alarm_list);
UNLOCK(pfdctx);
if(!palarm){
palarm = (alarm *) malloc(sizeof(alarm));
if(!palarm){
return NULL;
}
}
if(ptimeout->tv_sec < 0)
return NULL;
if(ptimeout->tv_usec < 0)
return NULL;
ptimeout->tv_sec += ptimeout->tv_usec/USEC_PER_SEC;
ptimeout->tv_usec = ptimeout->tv_usec%USEC_PER_SEC;
palarm->func = func;
palarm->param = param;
status = fdmgr_gettimeval(pfdctx, &t);
if(status < 0)
return NULL;
palarm->t.tv_sec =
t.tv_sec + ptimeout->tv_sec +
(t.tv_usec + ptimeout->tv_usec)/USEC_PER_SEC;
palarm->t.tv_usec = (t.tv_usec + ptimeout->tv_usec)%USEC_PER_SEC;
LOCK(pfdctx);
for( pa=(alarm *)pfdctx->alarm_list.node.next;
pa;
pa=(alarm *)pa->node.next){
if(pa->t.tv_sec > palarm->t.tv_sec){
break;
}
else {
if(pa->t.tv_sec == palarm->t.tv_sec){
if(pa->t.tv_usec > palarm->t.tv_usec){
break;
}
}
}
}
if(pa){
lstInsert(&pfdctx->alarm_list, pa->node.previous, palarm);
}
else{
lstAdd(&pfdctx->alarm_list, palarm);
}
UNLOCK(pfdctx);
return (void *) palarm;
}
/*
*
* fdmgr_clear_timeout()
*
*/
int
fdmgr_clear_timeout(pfdctx, palarm)
fdctx *pfdctx;
alarm *palarm;
{
int status;
LOCK(pfdctx);
status = lstFind(&pfdctx->alarm_list, palarm);
if(status != ERROR){
lstDelete(&pfdctx->alarm_list, palarm);
lstAdd(&pfdctx->free_alarm_list, palarm);
}
UNLOCK(pfdctx);
return status;
}
/*
*
* fdmgr_add_fd()
*
* this rouitine s only supplied for compatibility
* with earlier versions of this software
*/
int
fdmgr_add_fd(pfdctx, fd, func, param)
fdctx *pfdctx;
int fd;
void (*func)();
void *param;
{
int status;
status = fdmgr_add_fd_callback(
pfdctx,
fd,
func,
param,
NULL,
NULL,
NULL,
NULL);
return status;
}
/*
*
* fdmgr_add_fd_callbacks()
*
*/
int
fdmgr_add_fd_callback(pfdctx, fd, rd_func, rd_param,
wt_func, wt_param, excep_func, excep_param)
fdctx *pfdctx;
int fd;
void (*rd_func)();
void *rd_param;
void (*wt_func)();
void *wt_param;
void (*excep_func)();
void *excep_param;
{
fdentry *pfdentry;
LOCK(pfdctx);
pfdentry = (fdentry *) lstGet(&pfdctx->fdentry_free_list);
UNLOCK(pfdctx);
if(!pfdentry){
pfdentry = (fdentry *) calloc(1, sizeof(fdentry));
if(!pfdentry){
return ERROR;
}
}
pfdentry->fd = fd;
pfdentry->rd.pfunc = rd_func;
pfdentry->rd.param = rd_param;
pfdentry->wt.pfunc = wt_func;
pfdentry->wt.param = wt_param;
pfdentry->excp.pfunc = excep_func;
pfdentry->excp.param = excep_param;
pfdctx->maxfd = max(pfdctx->maxfd, fd+1);
LOCK(pfdctx);
lstAdd(&pfdctx->fdentry_list, pfdentry);
UNLOCK(pfdctx);
return OK;
}
/*
*
* fdmgr_clear_fd()
*
*/
int
fdmgr_clear_fd(pfdctx, fd)
fdctx *pfdctx;
int fd;
{
register fdentry *pfdentry;
int status;
status = ERROR;
LOCK(pfdctx);
for( pfdentry = (fdentry *) pfdctx->fdentry_list.node.next;
pfdentry;
pfdentry = (fdentry *) pfdentry->node.next){
if(pfdentry->fd == fd){
lstDelete(&pfdctx->fdentry_list, pfdentry);
fdmgr_finish_off_fdentry(pfdctx, pfdentry);
status = OK;
break;
}
}
/*
* also check entries which are currently in use
* and therefore undeletable until after the
* fdmgr gets thru fdmgr_pend_event
*/
for( pfdentry = (fdentry *) pfdctx->fdentry_in_use_list.node.next;
pfdentry;
pfdentry = (fdentry *) pfdentry->node.next){
if(pfdentry->fd == fd){
pfdentry->delete_pending = TRUE;
status = OK;
break;
}
}
UNLOCK(pfdctx);
/*
* If it is an ukn fd its a bug worth printing out
*/
if(status != OK){
printf("fdmg: delete of ukn fd failed\n");
}
return status;
}
/*
*
* fdmgr_finish_off_fdentry()
*
* !! LOCK(pfdctx) must be applied !!
*
*/
static void
fdmgr_finish_off_fdentry(pfdctx, pfdentry)
fdctx *pfdctx;
register fdentry *pfdentry;
{
FD_CLR(pfdentry->fd, &pfdctx->readch);
FD_CLR(pfdentry->fd, &pfdctx->writech);
FD_CLR(pfdentry->fd, &pfdctx->excpch);
lstAdd(&pfdctx->fdentry_free_list, pfdentry);
}
/*
*
* fdmgr_pend_event()
*
*/
int
fdmgr_pend_event(pfdctx, ptimeout)
fdctx *pfdctx;
struct timeval *ptimeout;
{
int status;
extern errno;
struct timeval t;
alarm *palarm;
/*
* This routine is declared here since is only
* intended for use by this routine. If other
* uses are needed then the locking issues must be
* reinvestigated
*/
void process_alarm_queue();
LOCK_FDMGR_PEND_EVENT(pfdctx);
pfdctx->select_tmo = FALSE;
palarm = fdmgr_add_timeout(pfdctx, ptimeout, select_alarm ,pfdctx);
process_alarm_queue(pfdctx, &t);
while(TRUE){
status = fdmgr_select(pfdctx, &t);
process_alarm_queue(pfdctx, &t);
if(status){
break;
}
if(pfdctx->select_tmo)
break;
}
if(pfdctx->select_tmo==FALSE)
fdmgr_clear_timeout(pfdctx, palarm);
UNLOCK_FDMGR_PEND_EVENT(pfdctx);
return OK;
}
/*
*
* fdmgr_select()
*
* returns TRUE if any labor was performed, otherwise FALSE
*
*/
static int
fdmgr_select(pfdctx, ptimeout)
fdctx *pfdctx;
struct timeval *ptimeout;
{
register fdentry *pfdentry;
int labor_performed;
int status;
labor_performed = FALSE;
LOCK(pfdctx);
for( pfdentry = (fdentry *) pfdctx->fdentry_list.node.next;
pfdentry;
pfdentry = (fdentry *) pfdentry->node.next){
if(pfdentry->rd.pfunc){
FD_SET(pfdentry->fd, &pfdctx->readch);
}
if(pfdentry->wt.pfunc){
FD_SET(pfdentry->fd, &pfdctx->writech);
}
if(pfdentry->excp.pfunc){
FD_SET(pfdentry->fd, &pfdctx->excpch);
}
}
UNLOCK(pfdctx);
status = select(
pfdctx->maxfd,
&pfdctx->readch,
&pfdctx->writech,
&pfdctx->excpch,
ptimeout);
if(status == 0){
return labor_performed;
}
else if(status < 0){
if(errno == EINTR)
;
else if(errno == EINVAL)
printf( "fdmgr: bad select args ? %d %d %d\n",
pfdctx->maxfd,
ptimeout->tv_sec,
ptimeout->tv_usec);
else
printf( "fdmgr: error from select %d\n",
errno);
return labor_performed;
}
pfdentry = (fdentry *) &pfdctx->fdentry_list.node;
while(TRUE){
void *pfunc;
LOCK(pfdctx)
pfdentry = (fdentry *) pfdentry->node.next;
if(pfdentry){
lstDelete(&pfdctx->fdentry_list, pfdentry);
/*
*
* holding place where it can be marked
* pending delete but not deleted
*
*/
lstAdd(&pfdctx->fdentry_in_use_list, pfdentry);
}
UNLOCK(pfdctx)
if(!pfdentry){
break;
}
/*
* check for read active
*/
if(FD_ISSET(pfdentry->fd, &pfdctx->readch)){
FD_CLR(pfdentry->fd, &pfdctx->readch);
(*pfdentry->rd.pfunc)(pfdentry->rd.param);
labor_performed = TRUE;
}
/*
* check for write active
*/
if(FD_ISSET(pfdentry->fd, &pfdctx->writech)){
FD_CLR(pfdentry->fd, &pfdctx->writech);
(*pfdentry->wt.pfunc)(pfdentry->wt.param);
labor_performed = TRUE;
}
/*
* check for excp active
*/
if(FD_ISSET(pfdentry->fd, &pfdctx->excpch)){
FD_CLR(pfdentry->fd, &pfdctx->excpch);
(*pfdentry->excp.pfunc)(pfdentry->excp.param);
labor_performed = TRUE;
}
LOCK(pfdctx)
lstDelete(&pfdctx->fdentry_in_use_list, pfdentry);
/*
* if it is marked pending delete
* reset it and place it on the free list
*/
if(pfdentry->delete_pending){
fdmgr_finish_off_fdentry(pfdctx, pfdentry);
}
else{
lstAdd(&pfdctx->fdentry_list, pfdentry);
}
UNLOCK(pfdctx)
}
return labor_performed;
}
/*
*
* process_alarm_queue()
*
* only to be called by fdmgr_pend_event(). If other uses
* come up then the locking must be revisited
*/
static void
process_alarm_queue(pfdctx, poffset)
fdctx *pfdctx;
struct timeval *poffset;
{
struct timeval t;
int status;
alarm *pa;
alarm *nextpa;
status = fdmgr_gettimeval(pfdctx, &t);
if(status < 0)
abort();
LOCK(pfdctx);
for(pa = (alarm*)pfdctx->alarm_list.node.next; pa; pa = nextpa){
if(pa->t.tv_sec > t.tv_sec)
break;
else if(pa->t.tv_sec == t.tv_sec)
if(pa->t.tv_usec > t.tv_usec)
break;
nextpa = (alarm*)pa->node.next;
lstDelete(&pfdctx->alarm_list, pa);
lstAdd(&pfdctx->expired_alarm_list, pa);
}
UNLOCK(pfdctx);
/*
* Done this way so I am not traversing the alarm que while
* they are in an alarm handler (and potentially modifying
* the alarm queue).
*/
/*
* no need to lock here since this list is only touched
* by this routine, this routine is not exported
* and I am only allowing one thread in fdmgr_pend_event()
* at at time.
*/
pa = (alarm*) pfdctx->expired_alarm_list.node.next;
while(pa){
(*pa->func)(pa->param);
pa = (alarm*)pa->node.next;
}
LOCK(pfdctx);
lstConcat(&pfdctx->free_alarm_list, &pfdctx->expired_alarm_list);
pa = (alarm *)pfdctx->alarm_list.node.next;
if(pa){
if(pa->t.tv_usec >= t.tv_usec){
poffset->tv_sec = pa->t.tv_sec - t.tv_sec;
poffset->tv_usec = pa->t.tv_usec - t.tv_usec;
}else{
/* else borrow */
poffset->tv_sec = pa->t.tv_sec - t.tv_sec - 1;
poffset->tv_usec = pa->t.tv_usec
+ USEC_PER_SEC - t.tv_usec;
}
}else{
poffset->tv_sec = 0;
poffset->tv_usec = 0;
}
UNLOCK(pfdctx);
}
/*
*
* select_alarm()
*
*/
static void
select_alarm(pfdctx)
fdctx *pfdctx;
{
pfdctx->select_tmo = TRUE;
}
/*
*
* fdmgr_gettimeval
*
*
*/
#ifdef UNIX
fdmgr_UNIX_gettimeval(pfdctx, pt)
fdctx *pfdctx;
struct timeval *pt;
{
struct timezone tz;
return gettimeofday(pt, &tz);
}
#endif
/*
*
* fdmgr_vxWorks_gettimeval
*
*
*/
#ifdef vxWorks
fdmgr_vxWorks_gettimeval(pfdctx, pt)
fdctx *pfdctx;
struct timeval *pt;
{
static unsigned long last;
static unsigned long offset;
unsigned current;
current = tickGet();
if(current<last){
offset += (~(unsigned long)0)/pfdctx->clk_rate;
}
last = current;
pt->sec = current/pfdctx->clk_rate;
pt->sec += offset;
pt->usec = ((current%pfdctx->clk_rate)*
USEC_PER_SEC)/pfdctx->clk_rate;
}
#endif