socket/opensock.c

   1 /* Create socket with an unspecified address family for use with ioctl.
   2    Copyright (C) 1999-2024 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <sys/socket.h>
  21
  22 /* Return a socket of any type.  The socket can be used in subsequent
  23    ioctl calls to talk to the kernel.  */
  24 int
  25 __opensock (void)
  26 {
  27   /* SOCK_DGRAM is supported by all address families.  */
  28   int type = SOCK_DGRAM | SOCK_CLOEXEC;
  29   int fd;
  30
  31   fd = __socket (AF_UNIX, type, 0);
  32   if (fd >= 0)
  33     return fd;
  34   fd = __socket (AF_INET, type, 0);
  35   if (fd >= 0)
  36     return fd;
  37   fd = __socket (AF_INET6, type, 0);
  38   if (fd >= 0)
  39     return fd;
  40   __set_errno (ENOENT);
  41   return fd;
  42 }