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0f00f2c3 LC |
1 | /* Hook for making the close() function extensible. |
2 | Copyright (C) 2009, 2010 Free Software Foundation, Inc. | |
3 | Written by Bruno Haible <bruno@clisp.org>, 2009. | |
4 | ||
5 | This program is free software: you can redistribute it and/or modify it | |
6 | under the terms of the GNU Lesser General Public License as published | |
7 | by the Free Software Foundation; either version 3 of the License, or | |
8 | (at your option) any later version. | |
9 | ||
10 | This program is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | Lesser General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU Lesser General Public License | |
16 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ | |
17 | ||
18 | #include <config.h> | |
19 | ||
20 | /* Specification. */ | |
21 | #include "close-hook.h" | |
22 | ||
23 | #include <stdlib.h> | |
24 | #include <unistd.h> | |
25 | ||
26 | #undef close | |
27 | ||
28 | ||
29 | /* Currently, this entire code is only needed for the handling of sockets | |
30 | on native Windows platforms. */ | |
31 | #if WINDOWS_SOCKETS | |
32 | ||
33 | /* The first and last link in the doubly linked list. | |
34 | Initially the list is empty. */ | |
35 | static struct close_hook anchor = { &anchor, &anchor, NULL }; | |
36 | ||
37 | int | |
38 | execute_close_hooks (int fd, const struct close_hook *remaining_list) | |
39 | { | |
40 | if (remaining_list == &anchor) | |
41 | /* End of list reached. */ | |
42 | return close (fd); | |
43 | else | |
44 | return remaining_list->private_fn (fd, remaining_list->private_next); | |
45 | } | |
46 | ||
47 | int | |
48 | execute_all_close_hooks (int fd) | |
49 | { | |
50 | return execute_close_hooks (fd, anchor.private_next); | |
51 | } | |
52 | ||
53 | void | |
54 | register_close_hook (close_hook_fn hook, struct close_hook *link) | |
55 | { | |
56 | if (link->private_next == NULL && link->private_prev == NULL) | |
57 | { | |
58 | /* Add the link to the doubly linked list. */ | |
59 | link->private_next = anchor.private_next; | |
60 | link->private_prev = &anchor; | |
61 | link->private_fn = hook; | |
62 | anchor.private_next->private_prev = link; | |
63 | anchor.private_next = link; | |
64 | } | |
65 | else | |
66 | { | |
67 | /* The link is already in use. */ | |
68 | if (link->private_fn != hook) | |
69 | abort (); | |
70 | } | |
71 | } | |
72 | ||
73 | void | |
74 | unregister_close_hook (struct close_hook *link) | |
75 | { | |
76 | struct close_hook *next = link->private_next; | |
77 | struct close_hook *prev = link->private_prev; | |
78 | ||
79 | if (next != NULL && prev != NULL) | |
80 | { | |
81 | /* The link is in use. Remove it from the doubly linked list. */ | |
82 | prev->private_next = next; | |
83 | next->private_prev = prev; | |
84 | /* Clear the link, to mark it unused. */ | |
85 | link->private_next = NULL; | |
86 | link->private_prev = NULL; | |
87 | link->private_fn = NULL; | |
88 | } | |
89 | } | |
90 | ||
91 | #endif |