Sweden-Number/server/select.c

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/*
* Server main select() loop
*
* Copyright (C) 1998 Alexandre Julliard
*/
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>
#include "server/object.h"
/* select user fd */
struct user
{
struct timeval when; /* timeout expiry (absolute time) */
struct user *next; /* next in sorted timeout list */
struct user *prev; /* prev in sorted timeout list */
const struct select_ops *ops; /* user operations list */
int fd; /* user fd */
void *private; /* user private data */
};
static struct user *users[FD_SETSIZE]; /* users array */
static fd_set read_set, write_set; /* current select sets */
static int nb_users; /* current number of users */
static int max_fd; /* max fd in use */
static struct user *timeout_head; /* sorted timeouts list head */
static struct user *timeout_tail; /* sorted timeouts list tail */
/* add a user */
int add_select_user( int fd, int events, const struct select_ops *ops, void *private )
{
int flags;
struct user *user = malloc( sizeof(*user) );
if (!user) return -1;
assert( !users[fd] );
user->ops = ops;
user->when.tv_sec = 0;
user->when.tv_usec = 0;
user->fd = fd;
user->private = private;
flags = fcntl( fd, F_GETFL, 0 );
fcntl( fd, F_SETFL, flags | O_NONBLOCK );
users[fd] = user;
set_select_events( fd, events );
if (fd > max_fd) max_fd = fd;
nb_users++;
return fd;
}
/* remove a user */
void remove_select_user( int fd )
{
struct user *user = users[fd];
assert( user );
set_select_timeout( fd, 0 );
set_select_events( fd, 0 );
users[fd] = NULL;
if (max_fd == fd) while (max_fd && !users[max_fd]) max_fd--;
nb_users--;
free( user );
}
/* set a user timeout */
void set_select_timeout( int fd, struct timeval *when )
{
struct user *user = users[fd];
struct user *pos;
assert( user );
if (user->when.tv_sec || user->when.tv_usec)
{
/* there is already a timeout */
if (user->next) user->next->prev = user->prev;
else timeout_tail = user->prev;
if (user->prev) user->prev->next = user->next;
else timeout_head = user->next;
user->when.tv_sec = user->when.tv_usec = 0;
}
if (!when) return; /* no timeout */
user->when = *when;
/* Now insert it in the linked list */
for (pos = timeout_head; pos; pos = pos->next)
{
if (pos->when.tv_sec > user->when.tv_sec) break;
if ((pos->when.tv_sec == user->when.tv_sec) &&
(pos->when.tv_usec > user->when.tv_usec)) break;
}
if (pos) /* insert it before 'pos' */
{
if ((user->prev = pos->prev)) user->prev->next = user;
else timeout_head = user;
user->next = pos;
pos->prev = user;
}
else /* insert it at the tail */
{
user->next = NULL;
if (timeout_tail) timeout_tail->next = user;
else timeout_head = user;
user->prev = timeout_tail;
timeout_tail = user;
}
}
/* set the events that select waits for on this fd */
void set_select_events( int fd, int events )
{
if (events & READ_EVENT) FD_SET( fd, &read_set );
else FD_CLR( fd, &read_set );
if (events & WRITE_EVENT) FD_SET( fd, &write_set );
else FD_CLR( fd, &write_set );
}
/* get a user private data, checking the type */
void *get_select_private_data( const struct select_ops *ops, int fd )
{
struct user *user = users[fd];
assert( user );
assert( user->ops == ops );
return user->private;
}
/* server main loop */
void select_loop(void)
{
int i, ret;
setsid();
signal( SIGPIPE, SIG_IGN );
while (nb_users)
{
fd_set read = read_set, write = write_set;
#if 0
printf( "select: " );
for (i = 0; i <= max_fd; i++) printf( "%c", FD_ISSET( i, &read_set ) ? 'r' :
(FD_ISSET( i, &write_set ) ? 'w' : '-') );
printf( "\n" );
#endif
if (timeout_head)
{
struct timeval tv, now;
gettimeofday( &now, NULL );
if ((timeout_head->when.tv_sec < now.tv_sec) ||
((timeout_head->when.tv_sec == now.tv_sec) &&
(timeout_head->when.tv_usec < now.tv_usec)))
{
timeout_head->ops->timeout( timeout_head->fd, timeout_head->private );
continue;
}
tv.tv_sec = timeout_head->when.tv_sec - now.tv_sec;
if ((tv.tv_usec = timeout_head->when.tv_usec - now.tv_usec) < 0)
{
tv.tv_usec += 1000000;
tv.tv_sec--;
}
ret = select( max_fd + 1, &read, &write, NULL, &tv );
}
else /* no timeout */
{
ret = select( max_fd + 1, &read, &write, NULL, NULL );
}
if (!ret) continue;
if (ret == -1) perror("select");
for (i = 0; i <= max_fd; i++)
{
int event = 0;
if (FD_ISSET( i, &write )) event |= WRITE_EVENT;
if (FD_ISSET( i, &read )) event |= READ_EVENT;
if (event) users[i]->ops->event( i, event, users[i]->private );
}
}
}