third_party/socket_wrapper/socket_wrapper.h

   1 /*
   2  * BSD 3-Clause License
   3  *
   4  * Copyright (c) 2005-2008, Jelmer Vernooij <jelmer@samba.org>
   5  * Copyright (c) 2006-2021, Stefan Metzmacher <metze@samba.org>
   6  * Copyright (c) 2013-2021, Andreas Schneider <asn@samba.org>
   7  * Copyright (c) 2014-2017, Michael Adam <obnox@samba.org>
   8  * Copyright (c) 2016-2018, Anoop C S <anoopcs@redhat.com>
   9  * All rights reserved.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  *
  15  * 1. Redistributions of source code must retain the above copyright
  16  *    notice, this list of conditions and the following disclaimer.
  17  *
  18  * 2. Redistributions in binary form must reproduce the above copyright
  19  *    notice, this list of conditions and the following disclaimer in the
  20  *    documentation and/or other materials provided with the distribution.
  21  *
  22  * 3. Neither the name of the author nor the names of its contributors
  23  *    may be used to endorse or promote products derived from this software
  24  *    without specific prior written permission.
  25  *
  26  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  36  * SUCH DAMAGE.
  37  */
  38
  39 #ifndef __SOCKET_WRAPPER_H__
  40 #define __SOCKET_WRAPPER_H__ 1
  41
  42 #include <stdbool.h>
  43
  44 /*
  45    Socket wrapper advanced helpers.
  46
  47    Applications with the need to alter their behaviour when
  48    socket wrapper is active, can link use these functions.
  49
  50    By default it's required for applications to use any of these
  51    functions as libsocket_wrapper.so is injected at runtime via
  52    LD_PRELOAD.
  53
  54    Applications using these functions should link against
  55    libsocket_wrapper_noop.so by using -lsocket_wrapper_noop,
  56    or implement their own noop stubs.
  57 */
  58
  59 /*
  60  * This returns true when socket wrapper is actively in use.
  61  */
  62 bool socket_wrapper_enabled(void);
  63
  64 /*
  65  * This allows socket_wrapper aware applications to
  66  * indicate that the given fd does not belong to
  67  * an inet socket.
  68  *
  69  * socket_wrapper may not be able to intercept the __close_nocancel()
  70  * syscall made from within libc.so. As result it's possible
  71  * that the in memory meta date of socket_wrapper references
  72  * stale file descriptors, which are already reused for unrelated
  73  * kernel objects, e.g. files, directories, ...
  74  *
  75  * Socket wrapper already intercepts a lot of unrelated
  76  * functions like eventfd(), timerfd_create(), ... in order
  77  * to remove stale meta data for the returned fd, but
  78  * it will never be able to handle all possible syscalls.
  79  *
  80  * socket_wrapper_indicate_no_inet_fd() gives applications a way
  81  * to do the same, explicitly without waiting for new syscalls to
  82  * be added to libsocket_wrapper.so.
  83  *
  84  * This is a no-op if socket_wrapper is not in use or
  85  * if the there is no in memory meta data for the given fd.
  86  */
  87 void socket_wrapper_indicate_no_inet_fd(int fd);
  88
  89 #endif /* __SOCKET_WRAPPER_H__ */