libseven/select.c

   1 /*
   2  *  ircd-ratbox: A slightly useful ircd.
   3  *  select.c: select() compatible network routines.
   4  *
   5  *  Copyright (C) 1990 Jarkko Oikarinen and University of Oulu, Co Center
   6  *  Copyright (C) 1996-2002 Hybrid Development Team
   7  *  Copyright (C) 2001 Adrian Chadd <adrian@creative.net.au>
   8  *  Copyright (C) 2002-2005 ircd-ratbox development team
   9  *
  10  *  This program is free software; you can redistribute it and/or modify
  11  *  it under the terms of the GNU General Public License as published by
  12  *  the Free Software Foundation; either version 2 of the License, or
  13  *  (at your option) any later version.
  14  *
  15  *  This program is distributed in the hope that it will be useful,
  16  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  *  GNU General Public License for more details.
  19  *
  20  *  You should have received a copy of the GNU General Public License
  21  *  along with this program; if not, write to the Free Software
  22  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
  23  *  USA
  24  *
  25  *  $Id: select.c 181 2006-12-18 02:56:07Z beu $
  26  */
  27
  28 #include "config.h"
  29
  30 #include "libseven.h"
  31
  32 #if HARD_FDLIMIT_ >= FD_SETSIZE
  33 #error HARD_FDLIMIT_ must be less than FD_SETSIZE(try using poll instead of select)
  34 #endif
  35 /*
  36  * Note that this is only a single list - multiple lists is kinda pointless
  37  * under select because the list size is a function of the highest FD :-)
  38  *   -- adrian
  39  */
  40
  41 fd_set select_readfds;
  42 fd_set select_writefds;
  43
  44 /*
  45  * You know, I'd rather have these local to comm_select but for some
  46  * reason my gcc decides that I can't modify them at all..
  47  *   -- adrian
  48  */
  49 fd_set tmpreadfds;
  50 fd_set tmpwritefds;
  51
  52 static void select_update_selectfds(int fd, short event, PF * handler);
  53
  54 /* XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX */
  55 /* Private functions */
  56
  57 /*
  58  * set and clear entries in the select array ..
  59  */
  60 static void
  61 select_update_selectfds(int fd, short event, PF * handler)
  62 {
  63         /* Update the read / write set */
  64         if(event & COMM_SELECT_READ)
  65         {
  66                 if(handler)
  67                         FD_SET(fd, &select_readfds);
  68                 else
  69                         FD_CLR(fd, &select_readfds);
  70         }
  71         if(event & COMM_SELECT_WRITE)
  72         {
  73                 if(handler)
  74                         FD_SET(fd, &select_writefds);
  75                 else
  76                         FD_CLR(fd, &select_writefds);
  77         }
  78 }
  79
  80
  81 /* XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX */
  82 /* Public functions */
  83
  84
  85 /*
  86  * init_netio
  87  *
  88  * This is a needed exported function which will be called to initialise
  89  * the network loop code.
  90  */
  91 void
  92 init_netio(void)
  93 {
  94         FD_ZERO(&select_readfds);
  95         FD_ZERO(&select_writefds);
  96 }
  97
  98 /*
  99  * comm_setselect
 100  *
 101  * This is a needed exported function which will be called to register
 102  * and deregister interest in a pending IO state for a given FD.
 103  */
 104 void
 105 comm_setselect(int fd, fdlist_t list, unsigned int type, PF * handler,
 106                void *client_data, time_t timeout)
 107 {
 108         fde_t *F = &fd_table[fd];
 109         s_assert(fd >= 0);
 110         s_assert(F->flags.open);
 111
 112         if(type & COMM_SELECT_READ)
 113         {
 114                 F->read_handler = handler;
 115                 F->read_data = client_data;
 116                 select_update_selectfds(fd, COMM_SELECT_READ, handler);
 117         }
 118         if(type & COMM_SELECT_WRITE)
 119         {
 120                 F->write_handler = handler;
 121                 F->write_data = client_data;
 122                 select_update_selectfds(fd, COMM_SELECT_WRITE, handler);
 123         }
 124         if(timeout)
 125                 F->timeout = CurrentTime + (timeout / 1000);
 126 }
 127
 128 /*
 129  * Check all connections for new connections and input data that is to be
 130  * processed. Also check for connections with data queued and whether we can
 131  * write it out.
 132  */
 133
 134 /*
 135  * comm_select
 136  *
 137  * Do IO events
 138  */
 139
 140 int
 141 comm_select(unsigned long delay)
 142 {
 143         int num;
 144         int fd;
 145         PF *hdl;
 146         fde_t *F;
 147         struct timeval to;
 148
 149         /* Copy over the read/write sets so we don't have to rebuild em */
 150         memcpy(&tmpreadfds, &select_readfds, sizeof(fd_set));
 151         memcpy(&tmpwritefds, &select_writefds, sizeof(fd_set));
 152
 153         for (;;)
 154         {
 155                 to.tv_sec = 0;
 156                 to.tv_usec = delay * 1000;
 157                 num = select(highest_fd + 1, &tmpreadfds, &tmpwritefds, NULL, &to);
 158                 if(num >= 0)
 159                         break;
 160                 if(ignoreErrno(errno))
 161                         continue;
 162                 set_time();
 163                 /* error! */
 164                 return -1;
 165                 /* NOTREACHED */
 166         }
 167         set_time();
 168
 169         if(num == 0)
 170                 return 0;
 171
 172         /* XXX we *could* optimise by falling out after doing num fds ... */
 173         for (fd = 0; fd < highest_fd + 1; fd++)
 174         {
 175                 F = &fd_table[fd];
 176
 177                 if(FD_ISSET(fd, &tmpreadfds))
 178                 {
 179                         hdl = F->read_handler;
 180                         F->read_handler = NULL;
 181                         if(hdl)
 182                                 hdl(fd, F->read_data);
 183                 }
 184
 185                 if(F->flags.open == 0)
 186                         continue;       /* Read handler closed us..go on */
 187
 188                 if(FD_ISSET(fd, &tmpwritefds))
 189                 {
 190                         hdl = F->write_handler;
 191                         F->write_handler = NULL;
 192                         if(hdl)
 193                                 hdl(fd, F->write_data);
 194                 }
 195
 196                 if(F->read_handler == NULL)
 197                         select_update_selectfds(fd, COMM_SELECT_READ, NULL);
 198                 if(F->write_handler == NULL)
 199                         select_update_selectfds(fd, COMM_SELECT_WRITE, NULL);
 200         }
 201         return 0;
 202 }
 203