302 lines
8.5 KiB
C
302 lines
8.5 KiB
C
/*
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* Server main select() loop
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*
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* Copyright (C) 1998 Alexandre Julliard
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <assert.h>
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#include <errno.h>
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#include <signal.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/poll.h>
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#include <sys/time.h>
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#include <sys/types.h>
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#include <unistd.h>
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#include "object.h"
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#include "thread.h"
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struct timeout_user
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{
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struct timeout_user *next; /* next in sorted timeout list */
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struct timeout_user *prev; /* prev in sorted timeout list */
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struct timeval when; /* timeout expiry (absolute time) */
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timeout_callback callback; /* callback function */
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void *private; /* callback private data */
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};
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static struct object **poll_users; /* users array */
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static struct pollfd *pollfd; /* poll fd array */
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static int nb_users; /* count of array entries actually in use */
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static int active_users; /* current number of active users */
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static int allocated_users; /* count of allocated entries in the array */
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static struct object **freelist; /* list of free entries in the array */
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static struct timeout_user *timeout_head; /* sorted timeouts list head */
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static struct timeout_user *timeout_tail; /* sorted timeouts list tail */
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/* add a user and return an opaque handle to it, or -1 on failure */
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int add_select_user( struct object *obj )
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{
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int ret;
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if (freelist)
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{
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ret = freelist - poll_users;
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freelist = (struct object **)poll_users[ret];
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}
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else
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{
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if (nb_users == allocated_users)
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{
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struct object **newusers;
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struct pollfd *newpoll;
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int new_count = allocated_users ? (allocated_users + allocated_users / 2) : 16;
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if (!(newusers = realloc( poll_users, new_count * sizeof(*poll_users) ))) return -1;
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if (!(newpoll = realloc( pollfd, new_count * sizeof(*pollfd) )))
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{
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if (allocated_users)
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poll_users = newusers;
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else
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free( newusers );
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obj->select = -1;
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return -1;
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}
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poll_users = newusers;
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pollfd = newpoll;
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allocated_users = new_count;
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}
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ret = nb_users++;
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}
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pollfd[ret].fd = obj->fd;
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pollfd[ret].events = 0;
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pollfd[ret].revents = 0;
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poll_users[ret] = obj;
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obj->select = ret;
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active_users++;
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return ret;
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}
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/* remove an object from the select list and close its fd */
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void remove_select_user( struct object *obj )
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{
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int user = obj->select;
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assert( user >= 0 );
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assert( poll_users[user] == obj );
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pollfd[user].fd = -1;
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pollfd[user].events = 0;
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pollfd[user].revents = 0;
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poll_users[user] = (struct object *)freelist;
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freelist = &poll_users[user];
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close( obj->fd );
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obj->fd = -1;
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obj->select = -1;
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active_users--;
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}
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/* change the fd and events of an object */
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void change_select_fd( struct object *obj, int fd, int events )
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{
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int user = obj->select;
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assert( poll_users[user] == obj );
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pollfd[user].fd = fd;
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pollfd[user].events = events;
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obj->fd = fd;
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}
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/* set the events that select waits for on this fd */
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void set_select_events( struct object *obj, int events )
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{
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int user = obj->select;
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assert( poll_users[user] == obj );
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if (events == -1) /* stop waiting on this fd completely */
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{
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pollfd[user].fd = -1;
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pollfd[user].events = 0;
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pollfd[user].revents = 0;
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}
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else if (pollfd[user].fd != -1) pollfd[user].events = events;
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}
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/* check if events are pending */
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int check_select_events( int fd, int events )
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{
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struct pollfd pfd;
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pfd.fd = fd;
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pfd.events = events;
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return poll( &pfd, 1, 0 ) > 0;
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}
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/* add a timeout user */
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struct timeout_user *add_timeout_user( struct timeval *when, timeout_callback func, void *private )
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{
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struct timeout_user *user;
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struct timeout_user *pos;
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if (!(user = mem_alloc( sizeof(*user) ))) return NULL;
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user->when = *when;
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user->callback = func;
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user->private = private;
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/* Now insert it in the linked list */
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for (pos = timeout_head; pos; pos = pos->next)
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if (!time_before( &pos->when, when )) break;
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if (pos) /* insert it before 'pos' */
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{
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if ((user->prev = pos->prev)) user->prev->next = user;
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else timeout_head = user;
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user->next = pos;
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pos->prev = user;
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}
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else /* insert it at the tail */
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{
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user->next = NULL;
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if (timeout_tail) timeout_tail->next = user;
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else timeout_head = user;
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user->prev = timeout_tail;
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timeout_tail = user;
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}
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return user;
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}
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/* remove a timeout user */
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void remove_timeout_user( struct timeout_user *user )
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{
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if (user->next) user->next->prev = user->prev;
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else timeout_tail = user->prev;
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if (user->prev) user->prev->next = user->next;
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else timeout_head = user->next;
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free( user );
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}
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/* add a timeout in milliseconds to an absolute time */
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void add_timeout( struct timeval *when, int timeout )
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{
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if (timeout)
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{
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long sec = timeout / 1000;
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if ((when->tv_usec += (timeout - 1000*sec) * 1000) >= 1000000)
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{
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when->tv_usec -= 1000000;
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when->tv_sec++;
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}
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when->tv_sec += sec;
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}
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}
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/* handle the next expired timeout */
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static void handle_timeout(void)
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{
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struct timeout_user *user = timeout_head;
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timeout_head = user->next;
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if (user->next) user->next->prev = user->prev;
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else timeout_tail = user->prev;
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user->callback( user->private );
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free( user );
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}
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/* SIGHUP handler */
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static void sighup_handler()
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{
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#ifdef DEBUG_OBJECTS
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dump_objects();
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#endif
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}
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/* SIGTERM handler */
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static void sigterm_handler()
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{
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close_registry();
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exit(1);
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}
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/* server main loop */
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void select_loop(void)
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{
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int ret;
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sigset_t sigset;
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struct sigaction action;
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/* block the signals we use */
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sigemptyset( &sigset );
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sigaddset( &sigset, SIGCHLD );
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sigaddset( &sigset, SIGHUP );
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sigaddset( &sigset, SIGINT );
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sigaddset( &sigset, SIGQUIT );
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sigaddset( &sigset, SIGTERM );
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sigprocmask( SIG_BLOCK, &sigset, NULL );
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/* set the handlers */
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action.sa_mask = sigset;
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action.sa_flags = 0;
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action.sa_handler = sigchld_handler;
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sigaction( SIGCHLD, &action, NULL );
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action.sa_handler = sighup_handler;
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sigaction( SIGHUP, &action, NULL );
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action.sa_handler = sigterm_handler;
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sigaction( SIGINT, &action, NULL );
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sigaction( SIGQUIT, &action, NULL );
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sigaction( SIGTERM, &action, NULL );
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while (active_users)
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{
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long diff = -1;
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if (timeout_head)
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{
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struct timeval now;
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gettimeofday( &now, NULL );
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while (timeout_head)
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{
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if (!time_before( &now, &timeout_head->when )) handle_timeout();
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else
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{
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diff = (timeout_head->when.tv_sec - now.tv_sec) * 1000
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+ (timeout_head->when.tv_usec - now.tv_usec) / 1000;
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break;
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}
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}
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}
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sigprocmask( SIG_UNBLOCK, &sigset, NULL );
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/* Note: we assume that the signal handlers do not manipulate the pollfd array
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* or the timeout list, otherwise there is a race here.
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*/
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ret = poll( pollfd, nb_users, diff );
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sigprocmask( SIG_BLOCK, &sigset, NULL );
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if (ret > 0)
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{
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int i;
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for (i = 0; i < nb_users; i++)
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{
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if (pollfd[i].revents)
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{
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poll_users[i]->ops->poll_event( poll_users[i], pollfd[i].revents );
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if (!--ret) break;
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}
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}
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}
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}
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}
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