connection.c

   1 /*
   2    Copyright (C) Andrew Tridgell 1998
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 2 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, write to the Free Software
  16    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  17 */
  18
  19 /* support the max connections option */
  20 #include "rsync.h"
  21
  22
  23 /****************************************************************************
  24 simple routine to do connection counting
  25 ****************************************************************************/
  26 int claim_connection(char *fname,int max_connections)
  27 {
  28         int fd, i;
  29
  30         if (max_connections <= 0)
  31                 return 1;
  32
  33         fd = open(fname,O_RDWR|O_CREAT, 0600);
  34
  35         if (fd == -1) {
  36                 return 0;
  37         }
  38
  39         /* find a free spot */
  40         for (i=0;i<max_connections;i++) {
  41                 if (lock_range(fd, i*4, 4)) return 1;
  42         }
  43
  44         /* only interested in open failures */
  45         errno = 0;
  46
  47         close(fd);
  48         return 0;
  49 }