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)