sysdeps/mach/hurd/pipe2.c

   1 /* Copyright (C) 1992-2023 Free Software Foundation, Inc.
   2
   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 #include <sys/stat.h>
  22 #include <unistd.h>
  23 #include <fcntl.h>
  24 #include <fcntl-internal.h>
  25 #include <hurd.h>
  26
  27 /* Create a one-way communication channel (pipe).
  28    Actually the channel is two-way on the Hurd.
  29    If successful, two file descriptors are stored in FDS;
  30    bytes written on FDS[1] can be read from FDS[0].
  31    Apply FLAGS to the new file descriptors.
  32    Returns 0 if successful, -1 if not.  */
  33 int
  34 __pipe2 (int fds[2], int flags)
  35 {
  36   int save_errno = errno;
  37   int result;
  38
  39   if (flags & ~(O_CLOEXEC | O_NONBLOCK))
  40     return __hurd_fail (EINVAL);
  41
  42   flags = o_to_sock_flags (flags);
  43
  44   /* The magic S_IFIFO protocol tells the pflocal server to create
  45      sockets which report themselves as FIFOs, as POSIX requires for
  46      pipes.  */
  47   result = __socketpair (PF_LOCAL, SOCK_STREAM | flags, S_IFIFO, fds);
  48   if (result == -1 && errno == EPROTONOSUPPORT)
  49     {
  50       /* We contacted an "old" pflocal server that doesn't support the
  51          magic S_IFIFO protocol.
  52          FIXME: Remove this junk somewhere in the future.  */
  53       __set_errno (save_errno);
  54       return __socketpair (PF_LOCAL, SOCK_STREAM | flags, 0, fds);
  55     }
  56
  57   return result;
  58 }
  59 weak_alias (__pipe2, pipe2)