close_on_fork.c

   1 /*
   2  * Copyright (C) 2005-2006 Andre Noll <maan@systemlinux.org>
   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., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
  17  */
  18
  19 /** \file close_on_fork.c manage a list of fds that should be closed on fork */
  20 #include "para.h"
  21 #include "list.h"
  22 #include "string.h"
  23
  24 static struct list_head close_on_fork_list;
  25 static int initialized;
  26
  27 /**
  28  * describes an element of the close-on-fork list
  29  *
  30  * \sa list.h
  31  */
  32 struct close_on_fork {
  33         /** the file descriptor which should be closed after fork() */
  34         int fd;
  35         /** the position in the close-on-fork list */
  36         struct list_head node;
  37 };
  38
  39 /**
  40  * add one file descriptor to the close-on-fork list
  41  *
  42  * \param fd the file descriptor to add
  43  */
  44 void add_close_on_fork_list(int fd)
  45 {
  46         struct close_on_fork *cof = para_malloc(sizeof(struct close_on_fork));
  47
  48         if (!initialized) {
  49                 INIT_LIST_HEAD(&close_on_fork_list);
  50                 initialized = 1;
  51         }
  52         cof->fd = fd;
  53         para_list_add(&cof->node, &close_on_fork_list);
  54 }
  55
  56
  57 /**
  58  * delete one file descriptor from the close-on-fork list
  59  *
  60  * \param fd the file descriptor to delete
  61  *
  62  * Noop if \a fd does not belong to the close-on-fork list.
  63  */
  64 void del_close_on_fork_list(int fd)
  65 {
  66         struct close_on_fork *cof, *tmp;
  67
  68         if (!initialized)
  69                 return;
  70         list_for_each_entry_safe(cof, tmp, &close_on_fork_list, node) {
  71                 if (fd != cof->fd)
  72                         continue;
  73                 list_del(&cof->node);
  74                 free(cof);
  75         }
  76 }
  77
  78 /**
  79  * call close(3) for each fd in the close-on-fork list
  80  */
  81 void close_listed_fds(void)
  82 {
  83         struct close_on_fork *cof;
  84
  85         if (!initialized)
  86                 return;
  87         list_for_each_entry(cof, &close_on_fork_list, node) {
  88                 PARA_DEBUG_LOG("closing fd %d\n", cof->fd);
  89                 close(cof->fd);
  90         }
  91 }