1  /* Copyright (C) 1998-2023 Free Software Foundation, Inc.
       2     This file is part of the GNU C Library.
       3  
       4     The GNU C Library is free software; you can redistribute it and/or
       5     modify it under the terms of the GNU Lesser General Public
       6     License as published by the Free Software Foundation; either
       7     version 2.1 of the License, or (at your option) any later version.
       8  
       9     The GNU C Library is distributed in the hope that it will be useful,
      10     but WITHOUT ANY WARRANTY; without even the implied warranty of
      11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      12     Lesser General Public License for more details.
      13  
      14     You should have received a copy of the GNU Lesser General Public
      15     License along with the GNU C Library; if not, see
      16     <https://www.gnu.org/licenses/>.  */
      17  
      18  #include <paths.h>
      19  #include <stdlib.h>
      20  #include <string.h>
      21  #include <unistd.h>
      22  #include <errno.h>
      23  
      24  
      25  /* Unlock the slave pseudo terminal associated with the master pseudo
      26     terminal specified by FD.  */
      27  int
      28  unlockpt (int fd)
      29  {
      30    char buf[sizeof (_PATH_TTY) + 2];
      31  
      32    /* BSD doesn't have a lock, but it does have `revoke'.  */
      33    if (__ptsname_r (fd, buf, sizeof (buf)))
      34      {
      35        if (errno == ENOTTY)
      36  	__set_errno (EINVAL);
      37        return -1;
      38      }
      39    return __revoke (buf);
      40  }
      41  libc_hidden_def (unlockpt)