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