close_on_fork.c

   1 /*
   2  * Copyright (C) 2005-2009 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /** \file close_on_fork.c Manage a list of fds that should be closed on fork. */
   8 #include "para.h"
   9 #include "list.h"
  10 #include "string.h"
  11
  12 static struct list_head close_on_fork_list;
  13 static int initialized;
  14
  15 /**
  16  * Describes an element of the close-on-fork list.
  17  *
  18  * \sa list.h
  19  */
  20 struct close_on_fork {
  21         /** The file descriptor which should be closed after fork(). */
  22         int fd;
  23         /** The position in the close-on-fork list. */
  24         struct list_head node;
  25 };
  26
  27 /**
  28  * Add one file descriptor to the close-on-fork list.
  29  *
  30  * \param fd The file descriptor to add.
  31  */
  32 void add_close_on_fork_list(int fd)
  33 {
  34         struct close_on_fork *cof = para_malloc(sizeof(struct close_on_fork));
  35
  36         if (!initialized) {
  37                 INIT_LIST_HEAD(&close_on_fork_list);
  38                 initialized = 1;
  39         }
  40         cof->fd = fd;
  41         para_list_add(&cof->node, &close_on_fork_list);
  42 }
  43
  44 /**
  45  * Delete one file descriptor from the close-on-fork list.
  46  *
  47  * \param fd The file descriptor to delete.
  48  *
  49  * Noop if \a fd does not belong to the close-on-fork list.
  50  */
  51 void del_close_on_fork_list(int fd)
  52 {
  53         struct close_on_fork *cof, *tmp;
  54
  55         if (!initialized)
  56                 return;
  57         list_for_each_entry_safe(cof, tmp, &close_on_fork_list, node) {
  58                 if (fd != cof->fd)
  59                         continue;
  60                 list_del(&cof->node);
  61                 free(cof);
  62         }
  63 }
  64
  65 /**
  66  * Close all fds in the list and destroy all list entries.
  67  *
  68  * This function calls close(3) for each fd in the close-on-fork list
  69  * and empties the list afterwards.
  70  */
  71 void close_listed_fds(void)
  72 {
  73         struct close_on_fork *cof, *tmp;
  74
  75         if (!initialized)
  76                 return;
  77         list_for_each_entry_safe(cof, tmp, &close_on_fork_list, node) {
  78                 PARA_DEBUG_LOG("closing fd %d\n", cof->fd);
  79                 close(cof->fd);
  80                 list_del(&cof->node);
  81                 free(cof);
  82         }
  83 }