kc3-lang/gnulib/lib/fd-hook.c

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• Hash : 7b089321
  Author :
  Date : 2025-01-01T09:24:36
  

  maint: run 'make update-copyright'
  

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• lib/fd-hook.c

• /* Hook for making file descriptor functions close(), ioctl() extensible.
     Copyright (C) 2009-2025 Free Software Foundation, Inc.
     Written by Bruno Haible <bruno@clisp.org>, 2009.
  
     This file is free software: you can redistribute it and/or modify
     it under the terms of the GNU Lesser General Public License as
     published by the Free Software Foundation; either version 2.1 of the
     License, or (at your option) any later version.
  
     This file is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     GNU Lesser General Public License for more details.
  
     You should have received a copy of the GNU Lesser General Public License
     along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  
  #include <config.h>
  
  /* Specification.  */
  #include "fd-hook.h"
  
  #include <stdlib.h>
  
  /* Currently, this entire code is only needed for the handling of sockets
     on native Windows platforms.  */
  #if WINDOWS_SOCKETS
  
  /* The first and last link in the doubly linked list.
     Initially the list is empty.  */
  static struct fd_hook anchor = { &anchor, &anchor, NULL, NULL };
  
  int
  execute_close_hooks (const struct fd_hook *remaining_list, gl_close_fn primary,
                       int fd)
  {
    if (remaining_list == &anchor)
      /* End of list reached.  */
      return primary (fd);
    else
      return remaining_list->private_close_fn (remaining_list->private_next,
                                               primary, fd);
  }
  
  int
  execute_all_close_hooks (gl_close_fn primary, int fd)
  {
    return execute_close_hooks (anchor.private_next, primary, fd);
  }
  
  int
  execute_ioctl_hooks (const struct fd_hook *remaining_list, gl_ioctl_fn primary,
                       int fd, int request, void *arg)
  {
    if (remaining_list == &anchor)
      /* End of list reached.  */
      return primary (fd, request, arg);
    else
      return remaining_list->private_ioctl_fn (remaining_list->private_next,
                                               primary, fd, request, arg);
  }
  
  int
  execute_all_ioctl_hooks (gl_ioctl_fn primary,
                           int fd, int request, void *arg)
  {
    return execute_ioctl_hooks (anchor.private_next, primary, fd, request, arg);
  }
  
  void
  register_fd_hook (close_hook_fn close_hook, ioctl_hook_fn ioctl_hook, struct fd_hook *link)
  {
    if (close_hook == NULL)
      close_hook = execute_close_hooks;
    if (ioctl_hook == NULL)
      ioctl_hook = execute_ioctl_hooks;
  
    if (link->private_next == NULL && link->private_prev == NULL)
      {
        /* Add the link to the doubly linked list.  */
        link->private_next = anchor.private_next;
        link->private_prev = &anchor;
        link->private_close_fn = close_hook;
        link->private_ioctl_fn = ioctl_hook;
        anchor.private_next->private_prev = link;
        anchor.private_next = link;
      }
    else
      {
        /* The link is already in use.  */
        if (link->private_close_fn != close_hook
            || link->private_ioctl_fn != ioctl_hook)
          abort ();
      }
  }
  
  void
  unregister_fd_hook (struct fd_hook *link)
  {
    struct fd_hook *next = link->private_next;
    struct fd_hook *prev = link->private_prev;
  
    if (next != NULL && prev != NULL)
      {
        /* The link is in use.  Remove it from the doubly linked list.  */
        prev->private_next = next;
        next->private_prev = prev;
        /* Clear the link, to mark it unused.  */
        link->private_next = NULL;
        link->private_prev = NULL;
        link->private_close_fn = NULL;
        link->private_ioctl_fn = NULL;
      }
  }
  
  #endif
  

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