1/* netconn.c -- is a particular file descriptor a network connection?. */
2
3/* Copyright (C) 2002-2005 Free Software Foundation, Inc.
4
5   This file is part of GNU Bash, the Bourne Again SHell.
6
7   Bash is free software; you can redistribute it and/or modify it
8   under the terms of the GNU General Public License as published by
9   the Free Software Foundation; either version 2, or (at your option)
10   any later version.
11
12   Bash is distributed in the hope that it will be useful, but WITHOUT
13   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
14   or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
15   License for more details.
16
17   You should have received a copy of the GNU General Public License
18   along with Bash; see the file COPYING.  If not, write to the Free
19   Software Foundation, 59 Temple Place, Suite 330, Boston, MA 02111 USA.
20*/
21
22#include <config.h>
23
24#include <bashtypes.h>
25#if ! defined(_MINIX) && defined (HAVE_SYS_FILE_H)
26#  include <sys/file.h>
27#endif
28#include <posixstat.h>
29#include <filecntl.h>
30
31#include <errno.h>
32
33#if defined (HAVE_UNISTD_H)
34#  include <unistd.h>
35#endif
36
37/* The second and subsequent conditions must match those used to decide
38   whether or not to call getpeername() in isnetconn(). */
39#if defined (HAVE_SYS_SOCKET_H) && defined (HAVE_GETPEERNAME) && !defined (SVR4_2)
40#  include <sys/socket.h>
41#endif
42
43/* Is FD a socket or network connection? */
44int
45isnetconn (fd)
46     int fd;
47{
48#if defined (HAVE_GETPEERNAME) && !defined (SVR4_2) && !defined (__BEOS__)
49  int rv;
50  socklen_t l;
51  struct sockaddr sa;
52
53  l = sizeof(sa);
54  rv = getpeername(fd, &sa, &l);
55  /* Posix.2 says getpeername can return these errors. */
56  return ((rv < 0 && (errno == ENOTSOCK || errno == ENOTCONN || errno == EINVAL)) ? 0 : 1);
57#else /* !HAVE_GETPEERNAME || SVR4_2 || __BEOS__ */
58#  if defined (SVR4) || defined (SVR4_2)
59  /* Sockets on SVR4 and SVR4.2 are character special (streams) devices. */
60  struct stat sb;
61
62  if (isatty (fd))
63    return (0);
64  if (fstat (fd, &sb) < 0)
65    return (0);
66#    if defined (S_ISFIFO)
67  if (S_ISFIFO (sb.st_mode))
68    return (0);
69#    endif /* S_ISFIFO */
70  return (S_ISCHR (sb.st_mode));
71#  else /* !SVR4 && !SVR4_2 */
72#    if defined (S_ISSOCK) && !defined (__BEOS__)
73  struct stat sb;
74
75  if (fstat (fd, &sb) < 0)
76    return (0);
77  return (S_ISSOCK (sb.st_mode));
78#    else /* !S_ISSOCK || __BEOS__ */
79  return (0);
80#    endif /* !S_ISSOCK || __BEOS__ */
81#  endif /* !SVR4 && !SVR4_2 */
82#endif /* !HAVE_GETPEERNAME || SVR4_2 || __BEOS__ */
83}
84